.S 433 e.

THE

ANNALS

OF

PHILOSOPHY.

NEW SERIES.

JANUARY TO JUNE, 1824-.

VOL. VII.

AN'D TWEVTY-THIRD FHOM THE COMMEXTEMEXT.

Xcn&on :

Printed by C. Baldwin, fine Bridgc-strtUi

FOR BALDWIN, CRADOCK, AND JOY,

PATERNOSTER-ROW.
1S2-L

TABLE OF CONTENTS

NUMBER I.— JANUARY.

P.gc

Observations on the Rock« of Mount Sorrel, and of the Neighbourhood of
Grooby, in Leicestershire. By W. Phillips, FLS. and S. L. Kent,

MGS. (With a Plate.) , 1

On the Crystalline Forms of Artificial Salts. By H. J. Brooke, Esq.

FRS. (continued) 20

On a new Phenomenon of Electro-magnetism. By Sir H. Davy, Bart. . 22
A Reply to some Observations in the Review of An Essay upon the Con-
stitution of the Atmosphere. By J. F. Daniell, FRS 26

Astronomical Observations. By Col. Beaufoy, FRS . 29

OnLupulin, as a Medicine. By N. Mill, Esq .... 29

On the Methods of employing the various Tests proposed for detecting the

Presence ef Arsenic. By R. Phillips, FRS. L. and E 30

Corrections in Right Ascension of 37 Principal Stars. By J. South, FRS. 37
Description of a New Thermoelectric Instrument. By the Rev. J. Cum-
uli ng, MA. FRS 46

On Organic Salifiable Bases. By MM. Dumas and Pelletier 47

On Felspar, Albile, Labrador, and Anorthite. By M. Gustavus Rose.

(With a Plate.) 49

Observations on the preceding Paper, with an Account of a new Mineral.

ByM. Levy, MA 59

Analytical Account of the Philosophical Transactions for J823, Part II.. 62

Proceedings of the Royal Society 65

Supposed Origin of the Art of Smelting Iron 72

Composition of Ancient Bronze • 73

Parhelia, &c 75

Effect of Heat in lessening the Cohesive Force of Iron 75

Correctness of Greenwich Observations 76

British Museum and Edinburgh Review 76

New Scientific Books 77

New Patents 78

Mr. Howard's Meteorological Journal 79

NUMBER II.— FEBRUARY.

Experiments on the Stability of Floating Bodies. By Col. Beaufoy, FRS.
(With a Plate) 81

IV CONTENTS.

Page

On the Liquefaction of Chlorine and other Gases. By Mr. Faraday 89

New Locality of the Skorodite. By W. Phillips, FLS 97

On Fluorine. By J. Smithson, FRS 100

On the Composition of the Ancient Ruby Glass. By Mr. Cooper 105

On the ensuing Opposition of Mars. By F. Baily, Esq. FRS. VPAS. . . 107

Table of the Salt Springs in Germany. By C. Keferstein 109

An Examination of some Egyptian Colours. By J. Smithson, FRS.... 115
On the Crystalline Forms of Artificial Salts. By H. J. Brooke, Esq. FRS.

(continued) 117

On the Occurrence of Cleavelandite in the older Rocks. By W. Phillips,

FLS. MGS 118

Astronomical Observations. By Col. Beaufoy, FRS 121

Improved Clinometer. By M. P. Moyle, Esq 122

Reply to the Editor. By Mr. Gray 1 23

Remarks upon the preceding Answer. By R. Phillips, FRS. &c 128

On the Detection of small Quantities of Arsenic. By Dr. Traill 131

Expansion of Gases. By Mr. Biggs 133

Account of a New Mineral. By M. Levy, MA 134

Corrections in Right Ascension of 37 Principal Stars. By James South,

FRS. (concluded) 136

Analytical Account of the Philosophical Transactions, for 1823, Part II.

(continued) '43

Proceedings of the Royal Society , 147

. . Linnean Society - 150

. . Astronomical Society -. 152

. Geological Society 153

, — • Meteorological Society of London 154

Dark and bright Lines traversing the Spectrum 154

Analysis of Cleavelandite 1 55

Copper Pyrites of Orijarva 1 55

Scapolite from Pargas 155

Manufacture of Pianoforte Wire 156

New Scientific Books 156

New Patents ,6 7

Mr. Howard's Meteorological Journal 158

NUMBER III.— MARCH.
On the Crystalline Forms of Artificial Salts. By H. J. Brooke, Esq.

FRS. (continued) l6t

On the Daily Variation of the Horizontal and Dipping Needles under a

reduced directive Power. By Peter Barlow, Esq. FRS 163

On an Improved Apparatus for the Analysis of Organic Products. By

Mr.Cooper. (With a Plate) 170

On the Ancient Tin Trade 175

On Fossil Shells. By L. W. Dillwyn, Esq. FRS 177

CONTKNTS. T

Page

On the Active Power of Dilatation of the Heart. By D. Williams, MD. 181

A Table of Equivalent Numbers 1S5

Astronomical Observations. By Col. Beaufoy, FRS 197

On Animal Remains found in Caves. By G. Cumberland, Esq 198

Comparative Temperature ofPisa and Penzance. By Mr. E. Giddy 200

An Account of the Volcanos at present in Activity. By M. Arago 201

On certain Instruments formerly used for the Purpose of Blasting in Lead

Mines. By Mr. Crawhall 214

On the Eclipses of Jupiter's Third and Fourth Satellites. By J. South,

Esq. FRS 217

Analytical Account of the Philosophical Transactions, for 1823, Part II.

(continued) 227

Proceedings of the Royal Society 229

Primary Forms of Sulphur 234

Uranite of Autun £35

Phosphorescence of Acetate of Lime 235

Chemical Examination of a Fragment of a Meteor 236

New Scientific Books 237

New Patents 238

Mr. Howard's Meteorological Journal 239

NUMBER IV.— APRIL.

On Expansions. By Mr. Crichton 241

On the Atomic Weight of Boracic and Tartaric Acids. By Dr. Thomson 245
Corrections in Right Asceusion of 37 Stars of the Greenwich Catalogue.

By J. South, FRS. (continued) 247

On Uranium. ByM. Arfwedson 253

Examination of the Oxidum Manganoso-Manganicum. By M. Arf-
wedson 267

On a New Mineral Substance. By M. Levy, MA 275

Examination of Babingtonite by the Blowpipe. By J. G. Children, Esq. 277

Astronomical Observations. By Col. Beaufoy, FRS 278

Meteorologxal Registers for 1 823 279

On the Transmission of Electricity through Fluids. By Mr. Woodward 283

Hints to an Edinburgh Reviewer. By W. Phillips, FLS 285

On the Crystalline Forms of Artificial Salts. By H. J. Brooke, Esq. FRS.

(continued) 287

Analysis of the Nitrates of Strontia, described in the preceding Paper. By

Mr. Cooper • 289

On a Submarine Forest in the Frith of Tay. By J. Fleming, DD. FUSE. 2g0
Analytical Account of the Philosophical Transactions, for 1823, Part II.

(concluded) ■ 298

Proceedings of the Royal Society 305

■ Astronomical Society 308

Geological Society 309

Meteorological Society 311

— — Medico-Botanical Society of London 31C*

Yl CONTENTS.

Page

On the Mountain Barometer 3 13

Vegetable Alkalies 314

Dcebereiner's Eudiometer 3 16

New Minerals 316

Death of Mr. Bowdich, in Africa 317

New Scientific Books 317

New Patents 318

Mr. Howard's Meteorological Journal 3 1 9

NUMBER V.— MAY.

Remarks on Solar Light and Heat. By Baden Powell, MA 321

Astronomical Observations. By Col. Beaufoy, FRS. . .' 328

On the Decomposition of the Metallic Sulphates by Hydrogen Gas. By

M. Arfwedson 329

Analysis of some Minerals. By M. Arfwedson 343

On the Theory of Evaporation. By J. Herapath, Esq 349

Chemical Examination of Analcime, Copper Pyrites, and Sulphuret of

Bismuth. By M. Rose 353

Memoir on some Geometrical Principles connected with the Trisection

of an Arc. By John Walker, Esq. (With a Plate) '356

On the Crystalline Forms of Artificial Salts. By H. J.Brooke, Esq. FRS.

and FLS. (continued) 364

Apparatus for producing Instantaneous Light. By the Rev. J. Gum-
ming, MA. FRS. and Professor of Chemistry in the University of

Cambridge 36 .">

On Nuttallite, a new Mineral. By H. J. Brooke, Esq. FRS. &c 366

Reply to Mr. Henslow. By Dr. Berger 367

Analytical Account of De la Beche's Selection of Geological Memoirs. . . 371

Proceedings of the Royal Society 383

• Linnean Society 386

Zoological Club 388

■ Astronomical Society 389

— Geological Society 89 1

•— *» Medico-Botanical Society of London 391

The Logan Stone in Cornwall overturned 392

The Rate of a Chronometer 392

Cheltenham Water 393

Detonating Silver and Mercury , 394

Absorption of Air by Mercury 394

Connexion of Phosphorescence with Electricity 395

Preparation of Oxide of Nickel 395

Prussian Blue 396

New Scientific Books 396

New Patents 307

Mr. Howard's Meteorological Journal 399

CONTENTS. T U

NUMBER VI.— JUNE.

Page

Remarks on Solar Lightand Heat. By Baden Powell, MA. (continued) . 401

Astronomical Observations. By Col. Beaufoy, FRS 406

Remarks upon Dr. Berger's Reply. By Prof. Henslow 407

An Account of the Logan Rock 410

Analysis of the Fulminate of Silver. By MM. Liebig and Gay-Lussac.

(With a Plate) 413

Analyses of the Chrysoberyls from Haddam and Brazil. By Mr. Henry

Seybert 427

Of Poisons, Chemically, Physiologically, and Pathologically considered.. 432
Speculations and Inquiries respecting the Action and Nature of certain

Compounds of Sulphur 444

On the Coliseum at Rome. By T. R. Underwood, Esq. MGS . . 448

Analysis of the Argillaceous Iron Ore. By R. Phillips, FRS. &c 448

Analytical Account of the Pharmacopoeia Collegii Regalis Medicorum

Londinensis, 1824 * 450

Proceedings of the Royal Society 458

' Geological Society 460

Meteorological Society 464

— — — — Medical Society 467

Hydriodate of Potash 468

Action of Hydrocyanic Acid on Vegetable Life ; 468

Diurnal Variation of the Barometer 46*8

On the Cause of Rotatory Motion 46y

On the Transmission if Electricity through other Fluids 469

Volatility of Salts of Strychnia 47O

Crystallization of the Subcarbonate of Potash 470

New Scientific Books , , 470

New Patents 47 1

Mr. Howard's Meteorological Journal 473

Index » 475

PLATES IN VOL. VII. (New Series.)

Plates. Page

XXIV.— Rocks ofMountSorrel 1

XXV. — On Felspar, Albite, Labrador, and Anorthite 49

XXVI.— On the Stability of Floating Bodies 81

XXVII. — Apparatus for the Analysis of Organic Products 170

XXVIII. — On some Geometrical Principles connected with the Trisec-

tion of an Arc 35G

XXIX.— On Fulminate of Silver 415

ERRATA.

Page 29, line \8,for Lapulin, read Lupnlin.
83, line 10, for Ther. read Thus.
325, line 19,/ur infringe, read impinge.
327, line 2, for assent, read agent.
3S4, line 4 from bottom, for L. Italioa, read L. Italica.
388, line 4, for Harleston, read Starston.
b,for Clarton, read Clacton.

■ «r*M*.»**** ■'■'"""'

ANNALS

or

PHILOSOPHY.

JANUARY, 1824.

Article I.

Observations on the Rocks of Mount Sorrel, of Charnwood Forest,
and of the Neighbourhood of Grooby, in Leicestershire. By
William Phillips, FLS. &c. and Samuel Luck Kent, MGS.
(With a Plate.)

The tract to which the following observations are confined,
may, in general terms, be said to be comprehended within a
triangle, of which the angles are Mount Sorrel, Grooby, and
Thrinkston. (See the annexed Map*, Plate XXIV.) Two sides
of this triangle are about nine miles in length, namely, from
Mount Sorrel to Thrinkston, and from Thrinkston to Grooby;
the third side, namely, from Mount Sorrel to Grooby, is
between five and six miles long. This triangle comprehends
rocks remarkably differing from those of the vast plain of new
red sandstone which they overtop, though not to any considera-
ble elevation, the highest point of the whole being Bardon Hill,
situated nearly midway between Grooby and Thrinkston, and
which attains the height of 853 feet above the level of the sea.
On the south-west of this tract, however, rocks of the same
nature as those near Grooby, are, according to Mr. Greenough's
map, to be found for some little distance ; but the extent of
these we did not visit.

The rocks of the. area we have mentioned vary greatly in their
external characters ; but before we proceed to describe them, it

* The accompanying map is not given as an accurate representation of the lornis of
the hills, but chiefly to assist the reader, or the traveller, in forming some idea of their
relative position.

Vew Series, vol. vn. b

2 Messrs. W. Phillips and Kent on [Jan.

may not be amiss to give a general outline of the principal fea-
ture of the district in question.

From the height which has already been mentioned, it will at
once be decided that it cannot be considered as mountainous,
but only hilly. The whole tract, however, may be divided into
three parts, when viewed in relation to its surface, and its geolo-
gical features. As regards the latter, it is divided only into two
parts in Mr. Greenough's map ; the green colour correctly
denoting the existence of trap rocks on the south-eastern parts
of the district, being incorrectly carried up to the north-eastern,
where an essentially different rock prevails, to the exclusion of
all others, and which is coloured red in the annexed map.
These two extremes are less elevated than the central and
western parts, which consist of another rock perfectly dissimilar
to either of the former.

The extreme extent of this tract on the east, is formed by the
cliffs above the town of Mount Sorrel : from near the summit of
these cliffs, which may be assumed scarcely to exceed at their
highest part the height of 150 feet above the river Soar, the
country descends gently on the west and south-west for about
two miles, if we except two or three well wooded hills, termed
Buddon's Wood, and attains its greatest depression along a line
extending by Swithland, Ttushfield, and Woodhouse, to Lough-
borough Park; and here the country is at least as low as the
general level of the red sandstone surrounding the tract of which
we are treating. The small patch forming the south-east angle
of our tract, which is coloured green in the annexed map, on the
north and north-west of Grooby, is generally of inconsiderable
height, the highest point being the knowl on which the windmill
stands close to Markfield. The remainder of our district
(coloured yellow in the map) may be considered as one large
hill, rising into frequent eminences, of which one of the most
lofty near the centre, Beacon Hill, is but little lower than Bar-
don Hill, the highest point of the whole. The short and nume-
rous valleys dividing these eminences, though much above the
general level of the new red sandstone, are nevertheless covered
by it in several instances ; and it is manifest that its beds repose
on the western side of Beacon Hill.

The numerous eminences already adverted to have received
each its own designation as a separate hill, and it is chiefly on
the summits of these that the nature of the rocks constituting
them is to be perceived, being frequently crowned by rugged and
bare masses, which, particularly as viewed from near Grace
Dieu, have a serrated outline. This district for some miles east
of Thrinkston, where the hills are numerous and very rugged, is
little or not at all cultivated, the depressions between and
among them being covered by a long and very coarse grass,
beneath which, in some instances, as near Pedler Hill, the
ground is extremely soft, and even swampy. The other parts
of the district, however, differ greatly from this in their general

1824.] the Rocks of Mount Sorrel, #&7 3

aspect, being often highly cultivated, even to near the summits
of the hills, as in the instance of the south-western side of
Beacon Hill, while the lower parts, in some few instances, are
well wooded, and even some of the loftier summits are crowned
with woods, as is the case with those termed the Outwoods,
NW of Beacon Hill, and the hill in which are situated those
slate quarries near Swithland, which are the most distant from
that place on the SE, and Bardon Hill to its very summit.
Everywhere, however, except where the eminences are crowned
by bare rocks, a herbage forms the surface, covering a more or
less deep alluvium of fawn-coloured, or reddish and loose earth,
as was frequently manifested by the labours of the mole, even
on some of the most elevated ridges ; and that this alluvium is
at least occasionally of considerable depth, is proved on the side
of Whittle Hill, in which are situated many little quarries of five
to fifteen feet deep, wrought in search of fragments and loose
pieces of that peculiar variety of the rock of the forest, so greatly
used in different parts of the kingdom for setting penknives,
and which is termed the Charnwood or Charley Forest hone.

This very slight sketch of the external characters of this tract,
will evince that the opportunities of judging of the nature of its
rocks is far more limited than could be wished, but suffices at
least to furnish such information as may serve, if not to deter-
mine, at least to afford some probable notion of the relative seras
o which they belong, even though some points must necessarily
oe left undecided.

These difficulties are, first, that having found it impossible to
discover the actual connexion of any two of the three rocks
constituting this tract, and which differ greatly in aspect and
composition, we are deprived of any direct means of ascer-
taining their relative periods of formation ; and, secondly,
that neither the one nor the other is seen reposing upon any
other rock which, in that case, might be assumed to be anterior,
and might therefore serve, in some degree, perhaps, to assist in
deciding their relative age. It is indeed true that we are justi-
fied in considering them older than the surrounding new red
sandstone, since its beds actually repose upon these rocks,
which pass away gradually beneath them. This circumstance,
which is visible in a quarry at the eastern end of the cliffs
above the town of Mount Sorrel, and to a still greater extent at
both extremes of an old and deserted slate quarry near Swith-
land, would seem to prove, that in the section annexed by the
llev. W. D. Conybeare to the " OuLliues of the Geology of
England and Wales," the rocks of Charnwood would have been
represented with somewhat greater accuracy, if instead of deli-
neating; the beds of the new red sandstone as abutting- against
them, their extremes had been shown reposing on them, and
the rocks of this district passing gradually, but at a considerable
angle, beneath them. As represented in that section, the rocks

b2

4 Messrs. W. Phillips and Kent on [Jan.

of the Forest may possibly serve to convey a notion that they
have been thrust up by some subterranean force — a notion
which we conceive would be erroneous, arguing from the
remarkable regularity with which the sandstone beds repose on
the rocks, dipping wherever they are visible at an angle not less
than six nor greater than eight degrees.

The regularity of the sandstone beds seems also to come in
proof of another fact ; namely, that the rocks of the Forest have
not suffered by convulsion — a conclusion strengthened by the
observation that the direction of the slaty cleavage of these
rocks, which is mostly apparent, or becomes so by the assist-
ance of the hammer, is everywhere either NW by W, and SE by
E, or differs but very slightly from it towards the W and E.

For the reasons which have already been given, we shall treat
separately of the rocks of the three parts into which this district
is divided, as the Mount Sorrel, the Charnwood, and the Grooby
tracts ; and first of the former.

Of the Rocks of Mount Sorrel.

The rocks of Mount Sorrel are admirably laid open to view by
means of a line of quarries overhanging the town, and giving to
these rocks the appearance of cliffs, perhaps one-third of a mile
in length, and of the average height of nearly 100 feet, but not
absolutely continuous. Other small and detached quarries are
wrought on the eastern side, the whole being chiefly for the
purposes of road-making. The rock when sound is broken into
the proper form for paving stones, which are shipped on the Soar
for various parts of the kingdom, when less so, for mending
roads in lieu of the gravel employed in the neighbourhood of
London, for which purpose the Mount Sorrel rock is far supe-
rior.* Immediately on quitting the town on the W, the rocks
sink beneath a comparatively low and verdant covering, for
some little distance, and then again swell into trifling elevations
a little south of the road passing from Mount Sorrel to Quorn-
den, or Quorn, as it is commonly termed by the inhabitants of
both places. In Buddon's Wood, which occupies the greater
part of these little eminences, and within half a mile of Quorn-
den, are situated two or three inconsiderable quarries, one of
which, however, is remarkable, as will presently be noted, for
the veins or dykes traversing the rock.

The openings abovementioned, together with a small one situ-
ated about a mile nearly SVV of Mount Sorrel, and called Simp-
son's Pit, remarkable also for its exhibiting the appearance of a
vary determinate dyke, form the whole catalogue of the
quarries observable in this rock, and which offer the principal

* We request thus to express our obligations to Jackson, Esq. residing at

Mount Sorrel, and the present proprietor of the quarries, for his polite attention in
directing our observation to every point which he considered the most likely to inte-
rest us.

1824,] the Rocks of Mount Sorrel, far, 5

opportunity for studying its nature. Some rocks, however,
appear in situ on an eminence between the town and Buddon's
Wood ; while some also overtop the surface of Rothley Plain,
of which the gradual descent begins at the abovementioned
quarry, called Simpson's Pit ; and in the earlier part of the
descent of this plain, rocks perfectly resembling those of Mount
Sorrel occasionally overtop the general surface, sinking, as has
already been observed, ultimately beneath it, and so completely
that it is impossible to discover their connexion with those of
the Forest.

The aspect of the Mount Sorrel rock is granitic, and hand
specimens may, perhaps, be found, of which the ingredients
appear to be confined to those commonly considered as being
essential to granite ; namely, quartz, felspar, and mica; for the
hornblende which generally is sufficiently apparent, and which
often abounds, is occasionally so nearly wanting, or so minute
in small specimens, that it may easily be overlooked. In reality,
however, much of that which appears to be felspar, is not that
mineral, but cleavelandjte. Epidote occasionally enters into its
composition, but is more generally found in small nests or veins,
with semi-transparent quartz, when it is sometimes associated
with magnesian carbonate of lime, which cleaves into rhom-
boids, and slowly effervesces, in diluted muriatic acid ; silvery
talc appears sometimes on the quartz found in veins or nests in
the rock, and the same substance of various colours enters into
the composition of some of those which overtop the grassy slope
of Rothley Plain. Chlorite also in small quantity is sometimes
diffused through the mass, and occasionally appears traversing
it in thin irregular veins.

The quartz entering into the composition of this rock is
transparent or semitransparent, the mica in thin hexagonal
plates, and the surfaces produced by dividing them parallel to
the terminal plane are very splendent and of a colour nearly
approaching to black, but by transmitted light the laminse appear
of a dingy-brown. The hornblende is of a dark bottle-green,
approaching to black. The felspar and cleavelandite, which are
almost constantly the prevailing substances, vary greatly in
colour, are intermingled in the mass, and cannot always be dis-
tinguished from each other by their external characters. Both
are commonly red or reddish, and this colour is sometimes so
powerful in the cleavelandite as to impart to it the aspect of red
jasper, particularly whenever it assumes in any degree the
appearance of a vein ; the planes produced by fracture are then
generally curvilinear, and without lustre. Sometimes, however,
the felspar and cleavelandite are intermixed, either simply, or in
such a manner as to impart to the rock a porphyritic character ;
the felspar is generally translucent, and the imbedded cleave-
landite white and nearly opaque, and the other ingredients of
the rock then form a small grained paste. We were not in the

6 Messrs. W. Phillips and Kent on [Jan.

first instance aware of the intermixture of these two minerals in
this rock, and considering the whole as felspar, we should have
contented ourselves with the observation that a part of it yields
to the pressure of the edge of the hard mineralogical knife,
which felspar does not, but for the discovery of M. Levy, that
much which has been considered as felspar is cleavelandite ; the
announcement of this in the Annals for November last, induced
us to examine all the varieties of this rock with great attention,
and we have been convinced of the intermixture of the two
minerals by procuring fragments from the same specimen ;
which, submitted to the reflective goniometer, afforded us sepa-
rately the angles of the two substances; felspar cleaves with
ease only in that direction which affords an angle of 90° ; while
cleavelandite yields with nearly equal ease parallel to all the
planes of its primary crystal, and we have consequently obtained
the measurement of all its angles.

The Mount Sorrel rock thus constituted* will be judged by
some to be a syenite ; while others will consider it to be a gra-
nite of the compound kind described by Dr. Mac Culloch, in his
excellent Treatise on Rocks, under the Third Division, relating
to that rock (p. 238), and it is to be regretted that no sufficient
means of determining its actual geological position (which alone
might settle the question) is afforded, since it is not seen in
connexion with any other rock, save the beds of the new red
sandstone, which, as has already been stated, repose on it.

But there are still some circumstances regard in<r this rock
which merit attention. It not unfrequently includes either
irregular or somewhat spherical masses, varying in size from
about an inch in diameter to nearly a foot, and possessing a totally
different aspect to the rock itself; some of these have at first
sight the appearance of fragments, but not even a close inspec-
tion with a glass can discover the precise line of junction with
the rock. Their aspect is fine-grained, and their composition
appears to be, minute quartz, felspar, hornblende, and chlorite,
apparently imbedded in a substance of a hair-brown colour,
which yields to the knife readily, and resembles steatite. The
mass partakes of a brown colour with a tinge of green, espe-
cially when moistened : in one instance, specks of yellow copper
ore and whitish pyrites were apparent ; in another, the same
ingredients are visible, and as effervescence is produced by the
application of diluted muriatic acid, it may be assumed also to
include calcareous spar.

This rock also contains veins or dykes : the substances of

* M r e must not make any particular exception of this rock, on account of its contain-
ing cleavelandite abundantly. This mineral has since been found entering into the com-
position of a porphyritic granite from Cornwall ; in the granite of Shap in Westmore-
land, and in a porphyry from Glen Tilt in Scotland, as announced in the slnnals for
December ; and still more recently in the porphyritic rocks of Charnwood Forest ; and
probably also in the neighbouring trap rocks of Grooby, in Leicestershire ; in each of
thet-e it is accompanied by felspar.

1824.] the Rocks of Mount Sorrel, %c. 7

these differ greatly in aspect and composition. In some
instances they are scarcely discernible from the rock itself which
incloses them ; in others, they appear to consist chiefly of
steatite ; and in others, of a substance which occasionlly has
much resemblance to the inclosed masses just adverted to, and
which, in one instance at least, is not to be distinguished by
the eye from fine-grained basalt.

The dykes of which the substance greatly resembles the rock
of Mount Sorrel, though in a somewhat disintegrated state, and
containing some reddish steatite, are situated not far from the
eastern extremity of the line of quarries at the back of the town :
they are two in number, both run E and W, have pretty determi-
nate walls, and are visible for about 12 feet ; that is, to the depth
at which the rock has been quarried where they occur. One
is about 20 inches wide at top, and after narrowing a little,
divides into two narrow branches ; the other is about two feet
wide, and underlies a little towards the north.

The veins or dykes which consist primarily of steatite, traverse
a rock perfectly resembling the reddest variety of Mount Sorrel,
in Beaumont's quarry, which is situated on the edge of Buddon's
Wood, beside a road leading from Quornden to Rothley, and
about half a mile from the former place. Three veins are here
visible which are parallel, run nearly due E and W, and each
may be traced on an average about 30 feet, the walls being
mostly very determinate : the two southern veins are about four
feet apart, and the third is about 22 feet on the north of the
nearest to it : they vary from 18 inches to two feet in thickness.
The substance of the southernmost vein, which underlies a little
to the south, is a greenish steatite, which is translucent,
yields to the pressure of the nail, and incloses a few specks of
hornblende and talc. Externally it is, however, in a state of
disintegration probably from exposure, and readily crumbles
down into a greyish-white, and somewhat unctuous powder ;
and in places it is associated with a harder substance which is
granular, and which has the aspect of steatite of a mixed red
and green colour, and incloses quartz and hornblende. The
steatite of the middle and northernmost veins, which are nearly
or quite vertical, is not quite so soft ; it incloses specks of horn-
blende and chlorite, together with small masses composed of a
reddish substance resembling hornstone, or compact felspar,
associated with decomposing hornblende. It is observed by
Dr. Mac Culloch, in treating of some of the more compound
varieties of granite described by him, that it is doubtful whether
the apparent steatite of some varieties may not be decomposed
talc or chlorite, an observation that may, perhaps, have some
bearing on the steatite of these veins.

On the face of the rock S of these veins, we observed a mass
of a bluish cast, about 20 feet wide, and 6 feet high, greatly re-
sembling the substance of the dykes, presently to be noticed, and

8 Messrs. W '. Phillips and Kent on [Jan.

reposing on the rock of the quarry, and bounded by it on each
side ; we could not, however, perceive the actual junction.

There are two dykes of which the substances much resemble
each other, except that in one part of one of them the rock has

freatly the external characters and appearance of a fine-grained
asalt. Just beside the road that divides the line of quarries
which overhang Mount Sorrel, we perceived among other stones
broken up for the repair of the roads, many fragments of a bluish
hue ; and on inquiries respecting the place from which they
were taken, a vein running nearly N and S, and about a foot
in thickness, was described to us as existing beneath the rubbish
just where the road turns to the left round the house inhabited
by a clergyman whose name we did not learn, but on the oppo-
site side of the road. We, therefore, did not see the dyke in
question. The rock has, in no inconsiderable degree, the aspect
of agranular basalt, and .though considerably hard, it yields to
pressure with the knife a grey powder pretty readily. The only
discernible substances in it are extremely minute and slender
crystals of transparent felspar, and sometimes cubic, sometimes
octohedral crystals of magnetic iron pyrites, together with occa-
sional specks of a yellowish-white substance which appears to
be laminated, but does not effervesce on the application of
diluted muriatic acid. The base or imbedding substance is not
sufficiently characterized to enable us to decide upon its nature;
it is, however, considerably soft, and when reduced to thin frag-
ments is translucent, of a slightly brownish hue, and contains
extremely minute specks of a dark-green colour. It seems, how-
ever, intimately connected with that of the mass constituting apart
of the dyke about to be described. This dyke is situated in the
small quarry called Simpson's Pit, in a rock perfectly resembling
that of Mount Sorrel, and about a mile SW of the town, at the
head of Rothley Plain. It appears to run through the mound in
which the quarry is situated nearly due N and S, is visible for
about 20 feet in height, is six feet wide at the lowest visible
place, and somewhat narrower at the surface, is nearly perpen-
dicular to the horizon, has very determinate walls, and reappears
about one-fourth of a mile SW in a field occupied by the landlord
of the Crown Inn at Mount Sorrel. The substance of this dyke
as it appears in the quarry, is of a bluish cast, yields readily to
the knife a grey powder, but is translucent in thin pieces, exhi-
biting, by the assistance of the glass, a multitude of dark specks
which appear occasionally to tinge the mass of a green colour ;
it scratches glass feebly (a circumstance not anticipated from
the use of the knife, and which may be owing to the presence
here and there of minute and slender crystals of felspar, or of
quartz too finely intermixed for observation), but its substance is
left on the glass. The mass itself has somewhat the aspect of
steatite, an aspect which is not to be observed where the dyke
reappears below : here it very greatly resembles a granular

1824.] the Rocks of Mount Sorrel, S)C 9

basalt, and is sufficiently hard to admit of a flat conchoidal
fracture ; it yields to the knife, though not without considerable
pressure ; is of a dark colour, owing to the thorough intermix-
ture of specks of a dark-green substance, and the slender crystals
of felspar are innumerable ; but neither quartz nor any other
mineral is to be detected even by the help of a highly magnify-
ing glass. The rock in immediate contact with this dyke did not
appear to have suffered any alteration.

The rocks of Mount Sorrel are occasionally also traversed by
small veins which more decidedly belong to the rock itself.
These veins sometimes resemble granular felspar, sometimes
granular quartz : they are always of a red hue : when of felspar,
they appear to include minute specks of quartz, hornblende, and
chlorite ; while those of quartz inclose crystals of quartz, felspar,
hornblende, and iron pyrites. The veins of white or translucent
quartz usually contain chlorite, and sometimes epidote.

No appearances of regular stratification are to be observed in
any of the quarries of this rock ; at the western termination of
their line at the back of the town, however, slabs of considera-
ble dimension are procured, owing to the presence of nearly
parallel fissures in two opposite directions, both being nearly
vertical, and those producing the largest plane, running nearly
due E and W. In the quarry at the other side of the hill, and
due E of the windmill on its summit, are to be seen some natu-<
ral cleavages in various directions, which, without sufficient
caution, might be mistaken for dykes.

Of the Rocks of Charnwood Forest,

The rocks of the district of Charnwood Forest, coloured
yellow in the accompanying sketch, differ greatly in respect of
aspect and composition, and vary so greatly in their external
characters, that although, from the circumstances attending
them, it is impossible to doubt their common origin, there are
varieties which, if taken separately, would, without previous
acquaintance with them, be judged to be of very different ages,
since even some of the proximate rocks appear to possess as
little mineralogical affinity as chalk and flint.

The greater part of these rocks are certainly schistose, but in
degrees varying from a fissility approaching that of common slate
to that of the rudest kind in which this seeming consequence of
structure is to be perceived; even the most completely schistose
varieties differ greatly in composition and external character ;
while those that are Least so often contain fragments of other
substances which, perhaps, tend to characterise the whole (since
all the varieties occur interstratified without any order), as belong-
ing to that class of rocks which are denominated by Dr.
Mac Culloch primitive slates ; by others grey wacke. And here
it may be pertinent to remark, that in no instance was any trace
of organic exuviee observed.

10 Messrs. W. Phillips aud Kent on [Jan.

The slate which most nearly approaches that of Wales in
colour and general characters is found in a small quarry at the
eastern extremity of Woodhouse Eaves, but it is not so fine, and
is less fissile. The still coarser varieties of the several quarries
near Swithland are preferred as roofing slates, though rarely less
than one-fourth of an inch in thickness, and frequently varying
to half an inch, being of unequal thickness throughout, with a
surface often undulating, though ' at odd times,' as the quarry-
men expressed it, they are reduced to one-eighth of an inch.
These slates are split by the workman while in a standing posi-
tion, the slafe being supported by one band covered by leather,
and also by the arm ; while it is struck on the upper end by the
other hand, with the edge of a sharp instrument, in form resem-
bling a cooper's adze. The general hue of these slatf.s is green-
ish, and they readily yield to the knife a greyish powder, a cir-
cumstance inducing the conclusion of their softness ; while, on
the other hand, their edges cut window glass freely, showing
them to be compounded of at least two substances differing
greatly in respect of hardness. The reapplication of the point
of the knife along the surface gently, and with the knife loosely
held by the hand, indicates the passing of the point from one
hard substance to another through a softer, the line of section
becoming consequently irregular. The thin edges of the slate
are translucent, when very thin approaching to transparent in
spots ; and by transmitted light it becomes evident, that the
greenish hue of the slate is derived from the presence of a mul-
titude of specks of a blackish-green colour, which we consider
to be chlorite, because veins of that substance are frequently seen
traversing the slates in connexion with opaque quartz. The
muriatic acid has no perceptible action on these slates ; and we
conceive them to consist of a granular quartz, and of chlorite,
imbedded in another mineral which is considerably soft : this
we believe to consist of silex and alumine, in a schistose form,
thus imparting its slaty character to the rock. On examining
these slates with a very powerful glass on 'the fractured edges at
right angles to the plane of cleavage, minute and brilliant sur-
faces are perceived which have the aspect of transparent quartz.
A vein of yellowish talc inclosing grains of quartz traverses the
quarry at the extremity of Woodhouse Eaves.

We have been the more particular in describing this slate,
which is the prevailing one of the country, from the belief that
all the varieties assumed by the rjcks of this tract, are consti-
tuted of the same materials, differing in their several proportions
and state of aggregation ; of course we do not include the foreign
substances imbedded in some of the varieties, and which occa-
sionally have the appearance of fragments, though we cannot
doubt from the composition and character, that some of the
included masses are of contemporaneous formation with the
rock itself. Hence it becomes requisite to give some account of

1824.] the Rocks of Mount Sorrel, fa. 1 1

the various forms in which these substances appear. In some
instances, the chlorite, instead of being disseminated throu°h-
out the mass, is arranged in irregular layers, thus imparting a
schistose character to it(Windgate Hill, Great Bucks Hill, &c.)

Near Swithland are several quarries of the slate just described,
one of which is estimated at 150 feet in length, and as much in
breadth and depth. In all the quarries the run of the ed°-e of
the slaty cleavage is, as before related, NW by W, and SEbyE,
the broad surface of the slate dipping about 72° towards the NE,
and it is to be remarked, that in each quarry, and particularly in
the largest, there is a run of the best slate, about 15 feet wide,
forming a kind of vein parallel with the direction of the cleavage,
and flanked on each side by an inferior kind of slate ; parallel
also to this vein of superior slates, is another vein (if so it may
be called) of a substance which is of a grey or greenish-grey
colour, of a granular appearance, and consisting apparently of
the imbedding substance or paste of the rocks of this district, in
which chlorite is abundantly disseminated in particles and nests,
and occasional specks of talc ; quartz, from its hardness, may
be concluded to be ah ingredient of the mass, but is too small
to be detected by the glass, and there is no appearance of
texture.

Other instances in which this substance assumes a granular
appearance occur, and without any perceptible mineral imbedded
in it (Hangingstones, Beacon Hill, &c.) : sometimes it forms a
paste of a dull-green colour, which appears nearly or altogether
homogeneous, possessing a splintery fracture, and varying greatly
in hardness (above Whittle Hill quarry, High Swanmore, Short
Cliff Hill) ; sometimes it is so soft as to yield readily to the
knife ; and the quartz is so sparingly disseminated through it,
that although it slightly scratches window glass, the substance
itself is left upon it as a grey powder (Hone-stone of Whittle
Hill) ; in other instances, it is much harder, owing most proba-
bly to the presence of a greater proportion of quartz, but still so
minute as to escape the eye (Bird Hill, Beacon Hill, and other
places) ; these varieties are generally fissile ; as well as others
in which chlorite is perceptible as giving the greenish tint to the
slate; in others, the green colour is totally wanting; the sub-
stance has then a yellowish tinge with every appearance of
homogeneity, is frequently hard, sometimes so hard, owing to
the abundant dissemination of siliceous particles throughout the
mass, as to resist the knife, and it then assumes the aspect of
compact felspar, or of hornstone (Bird Hill, base of Windgate
Hill, 8cc.) ; but a substance of the same nature and degree of
hardness also occurs, which is considerably schistose, greatly
resembles flinty slate, is greenish, arising, as is visible by trans-
mitted light through thin fragments, from the presence of chlo-
rite often disposed in irregular lines (Morley Hill quarry). All
these varieties are more or less slaty, and the laminae have the

12 Messrs. W.Phillips and Kent on [Jan.

same direction and dip as the more perfect slates of the quarries ;
but although they occur in layers varying from one-eighth of an
inch to two inches in thickness, these layers have not the same
direction as that of the cleavage ; but this we shall presently
describe.

The preceding may be said to constitute the principal varie-
ties of the imbedding substance or paste in what may be termed
its purer state ; in which, however, it is sometimes rendered
irregularly slaty, by the intervention of layers of chlorite ; the
substance then, as well as in some of the purer varieties, some-
what resembles potstone-

The quartz which forms so important a feature of the slates,
and which doubtless is more finely disseminated throughout the
harder varieties of the rock in the state of a mechanical mixture,
occurs in two instances at least under very different circum-
stances ; in one as a bed or vein of considerable dimension and
extent, of granular quartz, having the aspect of quartz rock, and
consisting apparently of grains of pure and nearly transparent
quartz closely and strongly aggregated without any intervening
cement ; this bed or vein occurs in Grooby Park, and appeared
to us to run in the direction of the slaty cleavage observable in
the quarries and elsewhere, and with the same dip. Slates were
observable on each side, though not in close contact with it.
In the other instance, compact quartz of a green colour, and
which but for the translucency of the edges might be mistaken
for green jasper, exists in layers in a large mass in a field behind
the last house of Newton Linford, which is most distant from
Grooby. It lies immediately between layers of the granular
looking varieties of the coarse slates before described, and with-
out any precise line of demarcation. But this rock will be more
fully described in adverting to the subject of the stratification of
the rocks of this district.

Hitherto we have not mentioned these rocks in their more
ordinary state of porphyries ; the aspect of these differs greatly
in different places ; but whatsoever their nature may be, they
are usually found connected with those we have already described,
and generally in layers alternating with them without any regu-
lar order of succession. Sometimes, however, they appear to
form almost exclusively the rocky eminences, already described
as receiving each its own individual name, and especially those
of the western part of the forest, near to Thrinkston.

The imbedded substances of the porphyritic rocks are various;
these consist of transparent crystals of quartz, which generally
are small, or of translucent crystals of felspar, often very minute,
and which frequently are macles, or hemitrope crystals, and also
of cleavelandite ; these substances occur either separately
(Broad Hill, Bardon Hill, &c.) or together in the same mass
(High Swanmore, High Sharpless, &c.) and they are rarely
abundant. Not unfrequently, however, instead of regular

1824.] the Rocks of Mount Sorrel, 8$c. 13

crystals, we find small angular fragments of quartz (base of
High Swanmore, &c.) which, when the surface of the imbedding
substance is somewhat decomposed into a white or greyish-
white and granular mass, of which the particles possess but little
cohesion, are left protruding. In other instances the fragments
of quartz are intermixed with the regular crystals of quarts* and fel-
spar (High Swanmore, &c). But the imbedded fragments gome-
times possess all the characters of the slate already described
as including irregular lines of chlorite, and as forming layers
between the other varieties of the rock (Morley Hill quarry), or
they resemble a reddish jasper which mostly is very hard, some-
times brittle (ridge of Bardon Hill), and occasionally other an-
gular fragments appear of less decided character. It is, how-
ever, manifest to us, that the imbedded substance occasionally
differs greatly from any of the preceding, in possessing altoge-
ther the appearance of some of the more- homogeneous and
greyish varieties of the rock itself, but much harder, and inclos-
ing transparent crystals of quartz, and occasionally of felspar ;
these occur in nodules, varying from the size of a nut to several
inches in diameter (Chamber Hill, Pedler Hill, ridge of Bardon
Hill) ; and though they may be separated from the rock from
which they project owing to the progress of its decomposition,
yet there does not appear to be any precise line of separation
between them; these, therefore, we consider to be of contem-
poraneous formation with the rock itself, as also may those
numerous specks and patches be, which at first sight appear like
imbedded fragments, but in reality present no line of separation
from the rock itself, and are generally harder ; they are of various
colours, grey, brown, or red (S W foot of Beacon Hill, Hi°-h
Sharpless, Little Gun Hill, &c.)

The paste of these porphyries consists of all the varieties of
the slaty rocks already described; but occasionally is much
harder than any of them, since it resists the knife completely,
owing, as we assume, to the mechanical diffusion of silex abun-
dantly throughout the mass, which then partakes little or not at
all of the schistose character (base of Windgate Hill, Pedler
Hill, 8cc.) and resembles hornstone or compact felspar.

In regard to the actual stratification of the rocks of Cham-
wood Forest, two opposite appearances claim attention.

It has been mentioned that the direction of the cleavage of
the slates and slaty rocks is everywhere nearly the same ; that
the edges of the slates uniformly run within a point or two of
N W by \V, and SE by E ; and that the only difference is
apparent in their more nearly approaching N W and SE. It has
also been mentioned, that in the largest quarry near Swithland,
a seam of the best slates runs in this direction, and parallel with
it a seam or vein of rock, quite different from the slate ; that in
the quarry close to Woodhouse Eaves, a seam or vein of talc

14 Messrs. W. Phillips and Kent on [Jan.

inclosing grains of quartz, takes the same course, and we may
add that on Old John Hill, in Grooby Park, and in other places,
some of the varieties of the slaty rocks obviously succeed each
other under the same circumstances. In Hind's new quarry
near Swithland, and in the quarry near Woodhouse Eaves, the
course of the best slates, which, in both cases, is about 12 feet
wide, is not parallel to the cleavage, but crosses it in both cases
at about the same angle, which, however, we did not ascertain.

We have also mentioned that the rocks of particular parts of
this district are banded of various colours, dependant, as we
assume, on examination, upon the quantity of chlorite, which
we have no doubt is the colouring substance of these rocks
generally, whenever, as is mostly the case, the hue is green or
greenish. These differently coloured bands or layers are disposed
with the utmost regularity parallel to each other, and vary from
the 16th of an inch, or even less, to some inches in thickness,
and the slaty rocks thus disposed comprehend almost every
variety found in the district. This appearance is particularly
obvious on Morley Hill, in the northern part of the district, on
the hill called Hanging Rocks on the eastern, on Old John Hill,
on the south-eastern ; while on the western side, as for some dist-
ance on the north of Whitwick, the rocks possess this character
in a less degree, and there is more confusion apparent among
them from the operation of external causes having left large
blocks piled in the rudest manner on each other.

Although these bands or layers are visible in the rocks of
several other hills besides those just mentioned, we select them
because, though there is a perfect uniformity on each hill, in
the dip and direction of the bands, each differs from the other in
these respects. On Morley Hill, the dip is 45° to the N ; on
the Hanging Rocks it is 45° to the E, and on Old John Hill 32°
to the S, but that of the rocks at the foot of it are 45°. It is
worthy of note, therefore, that as these several hills are situated
on the extremes or outer edges of the tract, the bands of each
dip away from the centre ; and if these regular layers be
taken as the order of deposit, and, therefore, as regular stratifi-
cation, they tend to show it to have taken place in the mantle-
shaped form.

But in whatever direction these lavers may dip, it is remarka-
ble that the dip and direction of the more slaty parts of the rock
is invariably as above quoted, and it is impossible to exhibit a
more striking instance of this fact, than is manifest in a rock
situated in a field at the south-western foot of Old John Hill,
and immediately behind the last house in Newton Linford.

1824.]

the Rocks of Mount Sorrel, fyc.

15

This rock, represented by the above sketch, is about 12 feet
high, and is constituted of alternate layers of green or greenish
rocks more or less slaty (SR), and of blue slates (S) ; the central
band consists, as do certain of the others, of some of the more
granular looking varieties of rock, alternating with that which has
already been described as greatly resembling a green jasper ;
there is no precise line of demarcation between them, nor does
there appear to be any schistose structure parallel with these
bands, except what is produced by long exposure to the atmo-
sphere, which acts of course differently on substances appa-
rently composed of very different materials, or, more accurately
speaking perhaps, of the same materials in very different propor-
tion, and consequent state of aggregation. The bands here, as
near the summit of the hill, dip to the S, but the angle differs ;
above it is 32°, here it is 45° ; the cleavage of the slates, how-
ever, which are interstratified with the rock, is in another direc-
tion, being perfectly consistent with that of the actual slates in
all other parts of the tract; namely, 72° to the NE; and it is
remarkable that the weathering of the rocks lying between the
slates has a tendency to separate them chiefly in the same
direction.

The weathering of these rocks, however, when composed of
more uniform materials, is too striking in one or two cases to be
passed over in silence. The masses chiefly seen on the hill
termed the Hanging Rocks, have almost altogether the form of
tetrahedrons, from two to six or eight feet high resting on the
base, and having one plane constantly dipping towards the E at
an angle of 45 , and this plane is parallel to the variously
coloured bands of which the whole mass is constituted, and
which in some cases have separated by the action of the atmo-
sphere upon them. The other instance is on the summit of
Beacon Hill : here the action has been carried still further : a

16 Messrs. W. Phillips and Kent on [Jan.

single rock about eight feet high stands in the form of a doubly
oblique prism, of which only the base is beneath the surface.

^Qx

This prism is traversed by crevices, or by indications of them
marked by imperfect lines parallel to all its planes ; and so com-
plete has been the action of the elements in some parts of this
rock, that we succeeded in extricating from it some natural
fragments in the form of the rock itself. This rock consists of
bands of somewhat different colours lying parallel to the upper
plane, and dipping towards the E at an angle of 45° ; these
bands differ but little in character, being mostly of the more gra-
nular-looking varieties, and considerably hard. Close to this
rock are several others of less dimension, but of the same form,
and whose upper planes dip at the same angle. It remains to
be added that we fotnd the only cleavage practicable by mecha-
nical force, though somewhat obscure, is in this rock parallel to
the ordinary cleavage of the slaty rocks of the country, and,
therefore, parallel to one of the sides of the prism, visible in the
preceding sketch. This, however, is one among a multitude of
proofs visible in various parts of the forest, that although no
other cleavage is attainable by mechanical means than that
which has so often been alluded to, yet a long exposure to the
elements produces similar effects in another direction ; and
hence are to be observed in various places, rhombic prisms of
this rock, but the angles at which the planes meet, are by no
means constant, and where the rock is not banded, as it is in
the above instance, the upper plane is altogether wanting.

In conclusion it may be observed, that although in several
instances (some of which have been quoted) these rocks
appeared to be stratified parallel to the cleavage plane — that is
to say, some of its varieties succeed each other in that direc-
tion, yet we are disposed to believe from examination, that the
stratification, which may be termed the order in which these rocks
were deposited, is in fact parallel to the variously coloured bands,

1824.] the Rocks of Mount Sorrel, fyc. 17

which always are in a direction different to that of the cleavage
plane of the slates — never at right angles to it.

It is impossible to view the rocks of Charnwood Forest either
in situ, or in hand specimens, without being forcibly struck with
their resemblance to several of those in many parts of North
Wales. The less perfect slates lying between the granular-
looking and imperfectly slaty rocks above Nantfrancon quarry,
almost perfectly resemble the coarse slates of the Swithlancl
quarries ; while in several of the granular varieties of the rocks
of the two tracts, the resemblance is absolutely perfect. Chlo-
rite is abundant, and appears to be the colouring matter of both ;
and both include small crystals of transparent quartz and of
felspar, when the rock is very coarsely slaty. In Charnwood
Forest, however, we perceived in many places layers containing
angular fragments of quartz, and which are left adhering to the
surface, owing to the decomposition of the rocks, which in that
state, like those of Wales, are of a greyish-white colour. In Wales,
however, the included fragments, which alone may suffice to
characterize the whole series of Charnwood as belonging to grey-
wacke, have not yet been describedas occurring, though from the
very great similarity of its rocks and coarser slates to of those the
Forest, they may probably hereafter be discovered ; for in
Wales the fragments hitherto observed in its rocks appear to be
chiefly confined to a slaty substance, not unlike flinty slate, and
which is actually found in situ between layers of the rock itself;
the same substance, as well as the nodules which appear to be
contemporaneous with the rock, is likewise found in Charnwood
Forest.

If, however, the characters of the rocks of some parts of
North Wales should hereafter decide them to be greywacke,
there are others in which the characters seem so absolutely
talcose, that it may be found difficult to assign the whole to one
common origin, and equally so to separate them, on account of
the close connexion of the whole as regards position and the
constant direction of the slaty cleavage through all the varieties.
In Wales this direction is about NE and SW, the slates being
either vertical, or dip at an angle of about 72° to the NW or
SE ; while in Charnwood Forest the upper edge of the slate
always runs about NW by W, and SE by E, dipping uniformly
about 72° a little to the east of N.

Assuming the direction of the variously coloured layers so
obvious in many parts of Charnwood Forest, to be that of the
stratification, which, perhaps, will scarcely be doubted, and
which, as has already been said, differs in different parts of the
tract, it may be remarked that this has not been observed in the
same degree in North Wales, although it is sufficiently visible
near the summit of the Cleweth, a point but little inferior in
elevation to that of Snowdon itself.

New Series, vol. mi. c

18 Messrs. W. Phillips mid Kent on [Jan.

Rocks of Grooby and its Neighbourhood.

Considering the nature of these rocks, which appear to belong
to the trap family, it would have been especially desirable to
have perceived their connexion either with those of the forest,
or of Mount Sorrel, to neither of which do they seem to possess
any affinity ; but although we anxiously sought the junction,
there did not appear any opportunity of perceiving it. Owing
to the causes before mentioned, we did not observe any place
where their approach appears on the surface nearer than about
one-fourth of a mile, as on the north of Markfield Knowl, which
consists of trap. It is remarkable that when this knowl is
viewed from the road from Grooby to Markfield, and just before
it turns southwards to that place, five ridges of the trap rock are
perceived running down its side in the direction of the slaty
cleavage of the rocks of Charnwood. We mention this fact as
it exists, without any suspicion of its cause, or that these rocks
have any connexion with slates of any kind, and especially with
those of the forest ; the spaces between the ridges are covered
by a thick herbage.

About one-fourth of a mile on the north of the lower extre-
mity of these ridges is a quarry beside the road from Grooby to
Thrinkston, and called Round Cliff Pit, in which the rocks of
Charnwood are broken for the purposes of the road, and which
here are traversed by veins of a yellowish-green substance,
which, from its hardness, and from the forms of some minute
crystals observed in crevices of the rock, we consider to be
epidote. The space between this quarry and the termination of
the ridges of trap at the foot of Markfield Knowl, is, however,
covered by grass, or by cultivated soil, except the small part
occupied by the road.

We observed this rock but partially ; namely, on the N in
Bradgate Park ; thence by Grooby Pool to Grooby, and from
the latter place by Markfield to Markfield Knowl ; but these
rocks extend, according to Mr. Greenough's map, S and SW of
the latter place, above two miles.

This rock consists primarily of hornblende often distinctly
laminated, intermixed with small masses, never exceeding the
size of a pea, of a reddish substance, often greatly possessing
the aspect of compact felspar, the fractured surfaces being com-
monly without lustre ; these two ingredients constitute the rock
in about equal proportions ; in other instances the red felspar (if
so it may be termed) has a distinct though not brilliant cleavage,
but only in one direction. With the reddish substance is often
associated another, either of a light or bottle-green colour, of
which the surfaces are more brilliant than those of the former,
and we succeeded in detaching several fragments, having cleav-
ages at least in two directions, but scarcely bright enough for
the use of the reflective goniometer : one of them, however,

1824.] the Rocks of Mount Sorrel, fyc. 19

afforded, by several trials, an angle so very near to one belong-
ing to cleavelandite, and which of course does not belong to
felspar, that we have scarcely a doubt of the existence of the
former mineral in this rock also ; the green crystals are some-
times obviously included in those of a red colour : and we con-
ceive it to be not improbable, that the close intermixture of these
two minerals in that which is termed compact felspar, will
account for the presence of soda and potash, both of which, it is
observed by Dr. Mac Culloch, are constant ingredients of that
substance. Both the red and green varieties yield to pressure
with a hard mineralogical knife, the green being somewhat the
softer of the two, and therefore appear to be less hard than
felspar usually is : sometimes this rock contains minute, slender,
and transparent crystals, which, from their superior hardness,
we consider to be felspar, and specks of green or of yellowish
steatite, and oxidulous iron in minute regular octohedrons ;
quartz is a frequent ingredient ; mica and epidote occur more
rarely ; in the quarry W of Grooby, we observed the rock
traversed by veins, in one instance two inches thick, of a hard
flesh-coloured substance, which may be cleaved into curvilinear
rhomboids, in the cavities of which were minute crystals in that
form ; and as these crystals, and the substance including them,
effervesce slightly, and dissolve slowly in diluted muriatic acid,
and as the crystals afforded angles of about 106° 30' by the
reflective goniometer, we conclude them to be magnesian car-
bonate of lime. The sides of the veins are coated with chlorite,
which also is included in the vein itself.

In the quarry on the E of Grooby, we perceived a vein of
quartz and chlorite, and some appearance of the rock being
traversed by a dyke in a N and S direction, but io too rude a
manner for us to ascertain the fact, the walls, or what we con-
ceived to be such, being very irregular and indeterminate, and
the substance of the supposed dyke being composed of the same
materials as the rock inclosing it, but much finer grained.

Although the connexion of these rocks with those of Cham-
wood Forest was not perceived, we consider it to be worthy of
note, that after descending the south-western slope of Beacon
Hill, and traversing a field at its base, we found, beside a small
brook, some rocks of very considerable dimension, aud which
we fully believed to be in situ, so perfectly resembling those of
Grooby, that it was impossible to doubt their identity of compo-
sition ; and it may be remarked that fragments of the same rock
almost constitute the walls of the neighbouring fields. Whether
this rock be a dyke, or in what manner it is connected with the
forest rocks of the surrounding elevations, we had no means of
ascertaining, since it is the only one which overtops the herbage
in this comparatively low situation.

c'J

20

Mr. Brooke on the

[Jan.

Article II.

On the Crystalline Forms of Artificial Salts.
By H.J.Brooke, Esq. FRS.

{Continued from vol. vi. p. 439.)

It has been suggested to me that these descriptions of the
crystalline forms of the salts ought to be accompanied by an
exact analysis of each, in order to avoid the chance of misnomer,
and to render the description of each complete. It certainly
would be more satisfactory to know the composition of the salts
described. This cannot, however, be conveniently given with
the figures, but I have stated generally the authority upon
which they have been severally named, and they may at any
time be compared with the forms of ascertained compounds.

Sulphate of Potash.

The primary form of this salt was, I believe, first determined
by Mr. Levy to be a right rhombic prism, and described in
ISo. 30 of the Royal Institution Journal; but probably from not
possessing sufficiently explanatory crystals, Mr. L. has not
pointed out the relation of its primary form to the bi-pyramidal
figure under which it generally occurs.

I have been enabled to do this in a
very satisfactory manner by means of a
compound crystal which 1 have obtained Fig. I.

from the solution of a portion of this salt
in distilled water.

Fig 1. is a single modified crystal.

M on M' 120° 30'

MonA 120 45

M on e 146 22

Aon c 146 10

tone' 131 12

Fig. 2 is the compound crystal, which
consists of three single crystals, so united
that their upper edges meet at angles of
120°, and consequently their planes of
junction incline to each other at the same
angle. Hence

MonM" 119° 30'

eone" 130 24

Fig. 2.

Fig. 3.

1824.] Crystalline Forms of Artificial Salts. 21

Fig. 3 is one of the common bi-pyramidal
crystals, whose relation to the preceding
figures may be perceived from the corres-
ponding letters on the planes.

The union of these three crystals at an
angle of 120° is a fact which requires some
little explanation.

It has been hitherto supposed, that when
crystals mutually intersect or penetrate each
other, the planes of intersection are parallel
to (he primary planes, or to secondary planes
resulting from some simple law of decre-
ment. And the theoretic order of arrange-
ment of the molecules of crystals seems to require this mode of
combination in intersecting crystals. But the union of the three
crystals which compose fig. 2 is probably the result of simple
accretion, in the same manner as crystals of different substances
are found adhering strongly together by the close apposition of
their surfaces ; with this distinction however between the two
cases, that the union of the crystals in fig. 2 is the result of some
law which does not govern the accidental union of heterogene-
ous crystals, nor always even of homogeneous ones.

I have been led to this conclusion relative to the structure of
these by-pyramidal crystals, from having observed an apparently
intersected crystal of chrysoberil, separate easily into six seg-
ments, the planes of section being sufficiently bright for measure-
ment with the reflective goniometer, and inclining to each other
at an angle of b'0°.

Sulphate of Soda.

I do not find any distinct cleavage in the
crystals of this salt, whose primary form is
an oblique rhombic prism.

PonM,or M' 101° 20'

P one, ore' 133 18

Pon/t 107 44

Pone' 130 45

MonM' 80 24

M on/* 130 12

Mon/ 162 38

Mon/f 139 48

Nitrate of Lead. — Nitrate of Barytes.

The primary form of these salts is a regular octahedron, but
the crystals are commonly so much flattened in one direction
that their relation to the primary form is not very apparent.

sa

Sir H. Davy on a

Fig. I. Fig. 5.

[Jan.

/x*--

^

P

.' "V

a, i

r

./.

•i

\

3f \

W/ 1 '

\.

Fig. 1 is the regular primary crystal resting on one of its
planes, and having its solid angles truncated.

P on P' 109° 28'

P on« 125 16

Fig. 2 is the more common shape of the secondary crystals,
resulting from a disproportionate extension of some of their
planes.

Article III.

On a new Phenomenon of Electromagnetism, By Sir Humphry
Davy, Bart. Pres. RS.*

O* a subject so obscure as electromagnetism, and connected
by analogies more or less distinct with the doctrines of heat,
light, electricity, and chemical attraction, it is not difficult to
frame hypotheses ; but the science is in a state too near its
infancy to expect the developewent of any satisfactory theory ;
and its progress can only be ensured by new facts and experi-
ments, which may prepare the way for extensive and general
reasonings upon its principles. Influenced by this opinion, I
am induced to lay before the Society an account of an electro-
magnetic phenomenon I observed about fifteen months ago in
the laboratory of the Royal Institution, and which I have lately
had an occasion of witnessing in a more perfect manner, through
the kindness of Mr. Pepys, by the use of a large battery, con-
structed under his directions for the London Institution, and
containing a pair of plates of about 200 square feet. In describ-
ing this phenomenon, I shall not enter into very minute details,
because the experiments, which led to the discovery of it, are
very simple, and, (hough more distinct with a large apparatus,
vet it may be observed by the use of a pair of plates containing
from ton to fifteen square feet.

Immediately after Mr. Faraday had published his ingenious

♦ From the Philosophical Transactions for 1823, Part II,

1824.] new Phenomenon of Electromagnet ism. 23

experiments on electromagnetic rotation, I was induced to try
the action of a magnet on mercury connected in the electrical
circuit, hoping that, in this case, as there Avas no mechanical
suspension of the conductor, the appearances would be exhibited
in their most simple form; and I found that when two wires were
placed in a basin of mercury perpendicular to the surface, and
in the voltaic circuit of a battery Avith large plates ; and the pole
of a powerful magnet held either above or below the wires, the
mercury immediately began to revolve round the Avire as an axis,
according to the common circumstances of electromagnetic
rotation, and Avith a velocity exceedingly increased when the
opposite poles of two magnets Avere used, one above, the other
below.

Masses of mercury of several inches in diameter were set in
motion, and made to revolve in this manner, whenever the pole
of the magnet Avas held near the perpendicular of the wire ; but
when the pole was held above the mercury between the two
wires, the circular motion ceased ; and currents took place in
the mercury in opposite directions, one to the right, and the
other to the left of the magnet. These circumstances, and
various others Avhich it would be tedious to detail, induced me
to believe that the passage of the electricity through the mer-
cury produced motions independent of the action of the magnet ;
and that the appearances Avhich I have described were owin°-to
a composition of forces.

I endeavoured to ascertain the existence of these motions in
the mercury, by covering its surface Avith weak acids ; and dif-
fusing over it finely divided matter, such as the seeds of lycopo-
diuiu, Avhite oxide of mercury, &c. but Avithout any distinct
result. It then occurred to me, that from the position of the
Avires, currents, if they existed, must occur chiefly in the lower,
and not the upper surface of the mercury; and I consequently
inverted the form of the experiment. I had two copper wires,
of about one-sixth of an inch in diameter, the extremities of
which Avere flat and carefully polished, passed through two
holes three inches apart in the bottom of a glass basin, and per-
pendicular to it ; they were cemented into the basin, and made
non-conductors by sealing-wax, except at their polished ends ;
the basin Avas then filled with mercury, which stood about a
tenth or twelfth of an inch above the wires. The Avires were
now placed in a powerful voltaic circuit. The moment the con-
tacts Avere made, the phenomenon, which is the principal object
of this paper, occurred : the mercury was immediately seen in
violent agitation ; its surface became elevated into a small cone
above each of the wires ; Avaves flowed off' in all directions from
these cones ; and the only point of rest Avas apparently Avhere
they met in the centre of the mercury between the two wins.
On holding the pole of a powerful bar magnet at a considerable
distance (some inches) above one of the cones, its apex Avas

24 Sir H. Davy on a [Jan.

diminished and its base extended : by lowering the pole further,
these effects were still further increased, and the undulations
were feebler. At a smaller distance the surface of the mercury
became plane ; and rotation slowly began round the wire. As
the magnet approached, the rotation became more rapid, and
when it was about half an inch above the mercury, a great
depression of it was observed above the wire, and a vortex,
which reached almost to the surface of the wire.

In the first experiments which I made, the conical elevations
or fountains of mercury were about the tenth or twelfth of an
inch high, and the vortices apparently as low; but in the expe-
riments made at the London Institution, the mercury being
much higher above the wire, the elevations and depressions were
much more considerable, amounting to the fifth or sixth of an
inch. Of course, the rotation took place with either pole of a
magnet or either wire, or both together, according to the well-
known circumstances which determine these effects.

To ascertain whether the communication of heat diminishing
the specific gravity of the mercury, had any share in these phe-
nomena, I placed a delicate thermometer above one of the
wires in the mercury, but there was no immediate elevation of
temperature ; the heat of the mercury gradually increased, as
did that of the wires ; but this increase was similar in every
part of the circuit. 1 proved the same thing more distinctly,
by making the whole apparatus a thermometer terminating in a
fine tube filled with mercury. At the first instant that the mer-
cury became electromagnetic, there was no increase of its
volume.

This phenomenon cannot be attributed to common electrical
repulsion ; for in the electromagnetic circuit, similar electrified
conductors do not repel, but attract each other ; and it is in the
case in which conductors in opposite states are brought near each
other on surfaces of mercury, that repulsion takes place.

Nor can the effect be referred to that kind of action which
occurs when electricity passes from good into bad conductors,
as in the phenomena of points electrified in air, as the follow-
ing facts seem to prove. Steel wires were substituted for copper
wires, and the appearances were the same in kind, and only less
in degree ; without doubt, in consequence of a smaller quantity
of electricity passing through the steel wires: and by comparing
the conducting powers of equal cylinders of mercury and steel
in glass tubes, by ascertaining the quantity of iron filings they
attracted, it was found that the conducting powers of mercury
were higher than those of steel; the first metal taking up
fifty-eight grains of iron filings, and the second only thirty-
seven.

Again ; fused tin was substituted for mercury in a porcelain
vessel into which wires of copper and steel were alternately
ground and fixed : the elevations were produced as in the mer-

1824.] new Phenomenon of Electromagnetism. 25

cury, and the phenomena of rotation by the magnet ; and it was
found by direct experiment, that the conducting powers of the
tin, at and just before its point of fusion, did not perceptibly
differ, and that they were much higher than those of mercury.
Lastly, the communication was made from the battery by two
tubes having nearly the same diameter as the wires filled with
mercury, so that the electricity, for some inches before it entered
the basin, passed through mercury ; and still the appearances
continued the same.

From the rapidity of the undulations round the points of the
cones, I thought they would put in motion any light bodies
placed above the mercury ; but I could not produce the slightest
motion in a very light wheel hung on an axle ; and when fine
powders of any kind were strewed upon the surface, they merely
underwent undulations, without any other change of place; and
fine iron filings strewed on the top of the cone, arranged them-
selves in right lines at right angles to the line joining the two
wires, and remained stationary, even on the centre of the cone.
The effect, therefore, is of a novel kind, and in one respect
seems analogous to that of the tides. It would appear as if the
passage of the electricity diminished the action of gravity on
the mercury. And that there is no change of volume of the
whole mass of the mercury appears from the experiment, p. 24 ;
and this was shown likewise by inclosing the apparatus in a kind
of manometer, terminating in a fine tube containing air inclosed
by oil ; and which, by its expansion or contraction, would have
shown the slightest change of volume in the mercury : none
however took place when the contacts were alternately made
and broken, unless the circuit was uninterrupted for a sufficient
time to communicate sensible heat to the mercury.

This phenomenon, in which the same effects are produced at
the two opposite poles, seems strongly opposed to the idea of
the electromagnetic results being produced by the transition
currents or motions of a single imponderable fluid.

On the conjectural part of the subject I shall not however
enter, for the reasons stated in the beginning of this paper; but
I cannot with propriety conclude, without mentioning a circum-
stance in the history of the progress of electromagnetism,
which, though well known to many Fellows of this Society, has,
I believe, never been made public, namely, that we owe to the
sagacity of Dr. Wollaston, the first idea of the possibility of the
rotations of the electromagnetic wire round its axis, by the
approach of a magnet; and 1 witnessed, early in 1821, an
unsuccessful experiment which he made to produce the effect
in the laboratory of the Royal Institution.

56 Mr. DanieWs Reply to %. [Jan.

Article IV.

A Reply to some Observations in the Revieiv of An Essay upon
the Constitution of the Atmosphere. By J. F. Daniell, FRS.

(To the Editor of the Annals of Philosophy.)

MY DEAR SIR, Goxecr.street, Dec. 10, 1823.

In the review of my Essay upon the Constitution of the
Atmosphere contained in the last number of the Annals, your
correspondent Z appears to me to have fallen into some miscon-
ceptions which I should be sorry to leave uncorrected in a work
of so much authority. I therefore trust that you will do me the
favour to spare me room for a short reply.

In the first place, it is objected to my theory, that " it
rests upon the sandy foundation of assumed partial changes of
temperature in the higher regions of the atmosphere, of the ex-
istence of which we have very insufficient evidence." This
assertion, I must own, greatly astonishes me : for I certainly
conceived that no meteorological fact rested upon better autho-
rity. I thought it indeed to be so generally admitted, that I did
not refer in my Essay to the particular observations upon which
it is founded, but merely illustrated it by the observation of
De Luc, of the sudden rise of temperature accompanying the
formation of cloud at a great elevation. I might now appeal, I
believe, to every ascent of every mountain, and every aerostatic
voyage, during which the thermometer has been consulted ; for
they all appear to me to agree in the same result. Among the
latter, more particularly, there are abundant instances in which,
not only the temperature of the atmosphere has not followed
the regular progression due to the density, but warm strata have
been found interposed between cold, and cold between warm.
I shall content myself, however, at present, with referring Z to
the simultaneous registers kept at the summit of St. Bernard
and at Geneva, and which are published every month in the
Bibliotheque Universelle. He will there find that the difference
of temperature between the two stations is perpetually varying,
and that, although the changes oscillate round the point of equi-
librium, the general law of the decrease for the altitude is only
developed from a mean of many observations.

The second objection is, " that to evolve so much heat as
would raise the temperature of a considerable mass of air, and
cause it to diffuse itself rapidly into distant regions, would
require the condensation of a greater quantity of aqueous vapour
than is likely to be present in any given space, and also that
this condensation should not be gradual, but should take place

1824.] Mr. Daniell's Reply to Z. 27

suddenly to a very great amount." From this extract I am
almost tempted to believe that Z has not done me the honour to
read my Essay, but only to review it. I have taken much pains
to show at p. 31, et seq. that such a sudden condensation of a
large quantity of vapour is not by any means requisite to pro-
duce an effect upon the barometer, but on the contrary, that a
gradual partial increase of temperature in the strata of an atmo-
spheric column of only two degrees is sufficient to depress the
mercury 063 in. If this part of my illustration should not have
been overlooked, I can only at present join issue upon the
opinion ; pledging myself to examine impartially and thankfully
any argument which Z may hereafter bring against my con-
clusions.

My reviewer objects in the third place to an error into which
not only myself but Mr. Leslie has fallen, viz. that the particles
of air in passing over the surface of the globe do not for a
moment cease to gravitate, and that no horizontal movement of
them will produce the slighest derangement in a perpendicular
direction. He observes, " Now it is well known that any
body, to which a projectile motion of five miles per second has
been imparted, would revolve around the earth like a planet, and
would cease to exert any pressure on its surface. Any less
velocity must produce a proportional decrease of weight in the
particles of air, which is known to move at the rate of from 60 to
100 miles per hour."

As this argument, if correct, is indeed decisively subversive
of my theory, I trust that I may be allowed to illustrate it some-
what particularly. According to the proposition set forth by Z,
a loaded waggon presses less upon the earth when at rest than
when in motion upon the road ! A steam boat must rise out of
the water in proportion to the velocity communicated to it by its
engine ! ! And many vessels must doubtless have been upon the
point of upsetting from this ill-understood cause ! ! ! To these
bodies, it is true, we cannot communicate a projectile motion of
five miles per second, but the former will move about five miles
per hour, and the latter probably ten, and " these lesser degrees
of velocity must produce a proportional decrease of weight."
Why a cannon ball indeed when projected from a gun does not
'mount in the air like a soap-bubble, is not quite obvious ; for such
a result one might undoubtedly expect from the theory of Z.
But to be serious : — With a laudable desire of correcting my
blunders, it is clear that the reviewer has fallen himself into an
error of no trivial importance. It is not true that any body to
which a projectile force of five miles per second has been
imparted, would revolve around the earth like a planet, unless
litis motion were to take place in vacuo, and were unopposed by any
pressure whatever: and no body that ever pressed at all upon the
burface of the earth would cease to exert such pressure in con-

28 Mr. Darnell's Reply to Z. [Jan.

sequence of any degree of projectile motion that might be com-
municated to it. It is not for me to surmise in what way it can
have been possible for your correspondent to confound together
pressure and gravitation, but certain it is that the planets do
not press upon the sun, nor the moon upon the earth. It is no
less certain that all the particles of the atmosphere do press upon
the earth, and, like the waggon upon the road, the vessel upon
the water, or the cannon ball in the air, their weight is in no
degree dependant upon their motion or rest.

These are the only objections brought forward by Z against
my theory of the Constitution of the Atmosphere ; but he
" suggests that the third table in Part I. is founded-upon an
erroneous principle." In reply to this, I must observe that the
tables in this part of my work were not meant to be accurate
representations of the different states of the atmospheric columns,
but mere rough approximations ; and their use is to assist the
mind in following the train of reasoning in the same way that
rudely-sketched diagrams assist the mathematician in solving a
problem of Euclid. The principle upon which they were con-
structed is this : I assumed the mean temperature of the latitude
for which I wished to calculate the atmospheric column as the
temperature of an homogeneous atmosphere ; and I thence
derived the pressures at different altitudes from the surface, and
from these the regular decrease of temperature for the density.
It is clear that for accurate purposes, both the pressures and
temperatures so obtained require correction, and that the tables
include an error which should be divided between the two, and
does not fall wholly upon the pressure as suggested by Z. The
labour of applying these corrections would have been very con-
siderable; and the tables, which, even in their present state,
cost me much pains, would not have better answered the pur-
poses of illustration.

In conclusion, I cannot but express my acknowledgments to
Z for the general courtesy of his review, but am still inclined to
appeal from his tribunal ; for I must own that my ambition
cannot yet content itself with the somewhat meagre consolation
which has been offered to me, that " there can be no discredit
to any one who fails to unfold the causes of phenomena which
have been acknowledged by one of the first philosophers of
the present times to have hitherto baffled all attempts to reduce
them to fixed principles."

I remain, dear Sir, yours most faithfully,

J. F. Daniell.

1824.] Col. Beaufoy's Astronomical Observations. 29

Article V.

Astronomical Observations, 1823.
By Col. Beaufoy, FRS.

Bushei/ Heath, near Stanmore.

Latitude 51° 37' 44-3" North. Longitude West in time 1' 20-93".

24'

41"

Mean Time at Bushey.

26

02

Mean Time at Greenwich.

21

19

Mean Time at Bushey.

22

40

Mean Time at Greenwich,

17

04

Mean Time at Bushey.

18

25

Mean Time at Greenwich,

Dec 7. Immersion of Jupiter's third < 9h

satellite j 9

Dec, 12. Immersion of .Jupiter's first C 12

satellite } 12

Dec. 12. Immersion of Jupiter's second ( 14

satellite { 14

A grievous error must exist in the time set down for the emersion of Jupiter's third
satellite, Dec. 7.

According to the Nautical Ephemeris, it should have taken place at 12 h 27' 01";
but after fruitlessly watching at the telescope until 14 h 29', that is for more than two
hours after the time specified, clouds relieved me from further attendance.

Article VI.

On Lapulin, as a Medicine. By Nicholas Mill, Esq.
(To the Editor of the Annals of Philosophy.)

SIR, Bridge Cottage, Camber-well, Nov. 20, 1823.

Having noticed in an American journal the experiments of
Dr. Ives at New York on the annon hop, and which appeared to
me of considerable importance in medicine, I was induced to
extend those inquiries, and apply the result, if beneficial, to prac-
tice among my own particular friends.

Preparations of the hop have been occasionally used in medi-
cine in this country. The whole of the plant has usually been
employed to form a tincture, but from the extraneous matter
introduced by this means, it has doubtless rendered this medi-
cine inert, if not prejudicial. Dr. Ives discovered that the true
aromatic bitter of the hop resided solely in a pulverulent matter,
which he called lupulin, for the collection, preparation, and
administration of which 1 am about to give specific directions.

Take any quantity of the best hops, and rub them strongly
between the hands, or put them in a bag, and beat them for
some time ; when the beating is completed, throw them on a
coarse wire sieve, which will only suffer the dust, &c. to pass
it; let them be well rubbed on the sieve till every thing has
gone through, except the leaves and steins of the plant ; reject
the leaves and stems altogether, and sift what has already passed

30 Mr. Mill on Lupulin, [Jan.

the wire through a lawn sieve ; nothing will now pass but a
very fine powder resembling red sand : this is the lupulin in
which the whole virtue of the hop resides.

The preparations of this substance which I have found to be
most efficacious are the decoction and tincture.

The decoction may be made by putting a sufficient quantity
of lupulin into a Florence flask, in a sand heat, and filling it three
parts full with distilled water ; boil the whole for half an hour,
and strain through cotton cloth. The solution thus obtained
will be feculent, and does not become clear by repose ; therefore
add, while hot, a small quantity of solution of gelatine in hot
water; shake the whole together, and let it remain till cold,
then filter through paper, and a clear yellow liquid will be
obtained. It is intensely, but not unpleasantly bitter ; and when
administered in doses of a tea-spoonful at a time in a table
spoonful of cold water, is a true stomachic. It is tonic, narcotic,
and aromatic. It does not produce constipation of the bowels,
as almost all other tonics do. It appears to act entirely on the
nervous system, and may be prescribed with manifest advantage
in all cases of debility and inaction of the digestive organs
where powerful tonics would be injurious.

The tincture may be prepared by digesting the lupulin in
strong and warm alcohol, till saturated, when it must be filtered
through paper, and a deep-red solution will be obtained.

From 40 to 60 minims of this tincture act as an anodyne, and
have a powerful effect in allaying great nervous irritation ; and
that stupidity which often accompanies the use of opium, is never
induced by this medicine.

I am, Sir, your obedient servant,

Nicholas Mill.

Article VII.

On the Methods of employing the various Tests proposed for
detecting the Presence of Arsenic. By R. Phillips, FRS. &c.

So much has at various times been offered to the public on
the subject of ascertaining the presence of arsenic, whether
taken from the stomachs, or mixed with the food of those who
have fallen victims to its poisonous agency, that some apology
may seem requisite for resuming the subject, more especially as
it has lately been treated of in so able a manner by Dr. Paris, in
his work on Medical Jurisprudence. My object on the present
occasion is not to offer any new test for arsenic : what I propose
is, to modify some of the methods of using the means already
known, and to simplify their application. I shall not enter into
any history of the various means which have been proposed, but

1824.] 1'ests for detecting the Presence of Arsenic. 31

confine myself to treating of the mode of employing the follow-
ing tests ; viz. the reduction of the arsenious acid to its metallic
state ; the use of sulphuretted hydrogen ; sulphate of copper ;
and nitrate of silver; and I hope to be able to describe
the little apparatus required in such a manner as to remove
some ambiguity and difficulty.

Jt is justly observed by Dr. Paris (Jurisprudence, vol. ii. p.
252), that " the detection of the presence of arsenic amidst a
complicated mass of alimentary matter has long been a problem
of interest and difficulty," because " coloured fluids are capable
of obscuring and changing, and even altogether preventing the
arsenical indications." Dr. Paris then adverts to the proposal
of M. Orfilato destroy or modify the colouring matter by means
of chlorine; this method is justly stated to be liable to great
difficulties in its application, and from sources too obvious to
require notice. Dr. Paris, therefore, advises that a solution of
ammoniuret of silver should be added to the fluid to precipitate
indiscriminately all bodies which it may be capable of so affect-
ing ; and then subjecting the precipitate to the action of black
flux in a glass tube for the purpose of subliming the arsenic
in its metallic state.

On considering this part of the subject, it appeared to me that
animal charcoal (ivory-black) might be advantageously employed
for the purpose of destroying the colouring matter. I there-
fore, mixed some of it with a coloured solution of arsenious
acid, viz. the liquor arsenicalis of the London Pharmacopoeia.
I found that the colouring matter was so completely destroyed
in a few minutes, that the test of nitrate of silver, or any other,
might be readily applied. I repeated this experiment with port
wine, gravy soup, and a strong infusion of onions *, and suc-
ceeded in these cases in procuring a solution sufficiently co-
lourless for the application of the most delicate tests. It might
be supposed that the phosphoric acid which the animal charcoal
contains might have some share in the production of the yellow
precipitate with silver ; I found, however, that water or wine
which was merely digested on the animal charcoal, produced
no effect with the nitrate of silver, excepting a slight precipitate
of chloride ; and to prevent this, the ivory-black should be
washed on a Alter with boiling distilled water, till the fluid run-
ning through ceases to be aflected by nitrate of silver. If, how-
ever, the ivory-black is of good quality, this precaution is un-
necessary.

Of Sulphuretted Hydrogen.

Supposing the substance suspected to contain arsenious acid,
to have been boiled in distilled water without any alkali, and
deprived of its colouring matter as now described, the test to

• I particularly mention infusion of onions, because much stress has been laid uprft
the ambiguity which its yellow colour may occasion. It immediately becomes colourless
(Urn: Paris and i'onblanqne's Med. Jurisprudence, vol. iii. p. I'J'J.')

32 Mr. R. Phillips on the [Jan.

which it may at first be subjected is a solution of sulphuretted
hydrogen gas in water. This is to be preferred to any coloured
fluid containing sulphuretted hydrogen, such as the hydrosul-
phuret, or, perhaps more properly, hydroguretted sulphuret of
ammonia ; for this fluid possesses the colour when diluted,
which we expect to produce by the action of sulphuretted
hydrogen upon arsenious acid. The method of preparing this
solution of the gas is perfectly simple. Put into an oil flask
about two ounces of muriatic acid undiluted with water, and an
ounce and a half of powdered sulphuret of antimony ; fit a cork
to the flask, and pass through it the shorter leg of a small hollow
glass tube twice bent at right angles ; pass the longer leg of the
tube into a vial containing distilled water, and then by the heat
of a spirit-lamp applied to the flask, sulphuretted hydrogen gas
will be readily procured, and though much of it will escape, yet
a sufficient quantity will be dissolved by the water. If distilled
water cannot be procured, then rain water may be used, or if
that be not at the moment obtainable, water, which has been
boiled and become clear, must be substituted. The annexed cut
will sufficiently explain this apparatus.

A\

d_o

X

If a glass tube is not at hand , one may be readily formed of
tin plate soldered. I have employed one for the purpose of
trying the experiment, which was made in about an hour; the
shorter leg may be about two inches and a half to three inches
long ; the intermediate space, and the longer leg, each six inches
in length ; the diameter may be about one-fourth of an inch ;
this passed through the cork, and used instead of the glass one,
answers the purpose perfectly, notwithstanding the tin is
slightly acted upon by the gas during its passage, and by the
solution in which it is immersed.

To this solution, clear and colourless, add, in a wine glass, or
a vial, some of the suspected fluid ; if it contain arsenious acid,
a yellow-coloured fluid will be produced, and, after the lapse of
£ome hours, a yellow precipitate will fall down. It has been
objected to this test, that antimony produces a similar appear-

1824.] Tests for detecting the Presence of Arsenic. 33

ance; while, however, there exists some resemblance in the co-
lours, there are these differences in the effects ; antimony fur-
nishes a precipitate immediately, and with more of an orange tint.

Sulphate of Copper.

Arsenious acid produces no effect upon a solution of sulphate
of copper ; but with the assistance of an alkali, a green precipi-
tate of arsenite of copper is readily produced. It has been
objected to this test, that a fallacious appearance is produced if
the suspected solution be of a yellow colour ; but for this case I
have already provided. If the sulphate of copper be impure,
owing to the presence of peroxide of iron, a greenish precipitate
may also be obtained by simply adding potash to the solution.
This test may be employed in two ways ; first, add a few drops of
an alkaline solution, as potash or its s«6-carbonate to the suspect-
ed solution, and when mixed pour them into the sulphate of cop-
per. If arsenious acid be present, a green precipitate will be form-
ed ; and there is a mode of removing any ambiguity which, if it
does not escape my recollection, has not been previously noticed.
To be certain that the sulphate of copper contains no peroxide
of iron, add first to the solution some potash ; if pure, a fine blue
precipitate will be obtained ; to this add the suspected solution ;
and if arsenious acid be present, then it will convert the blue
precipitate to a green one.

Nitrate of Silver.

To confirm the results obtained by sulphuretted hydrogen and
sulphate of copper, nitrate of silver is a test which may be very
usefully employed. The first method is simply to add the sus-
pected solution to one of nitrate of silver, which should be pre-
pared either from the crystallized or fused nitrate (lunar caustic),
in order that all excess of acid may be avoided. After the
suspected solution has been mixed with that of silver, drop in
a solution of ammonia or of potash, liquor ammoniae, or liquor
potassae of the London Pharmacopoeia ; if arsenious acid be
present, a bright-yellow precipitate of arsenite of silver will be
formed, which is readily dissolved by excess either of ammonia
or nitric acid ; so that supposing too much ammonia to have
been employed, nitric acid will restore the precipitate. Potash
does not possess the inconvenience of ammonia in redissolving
the arsenite of silver formed : but there is one inconvenience
attending the use of silver ; the animal fluids all contain mu-
riatic "salts ; and, therefore, the fluid contents of the stomach
will probably give a white precipitate of chloride of silver when
mixed with the nitrate. If, however, the presence of arsenic
has been determined by the use of the preceding tests, then
the chloride and arsenite of silver must be precipitated together,
Netu Series, vol. vii. j>

34 Mr. R. Phillips on the [Jan.

and the mixture, after being dried, must be subjected to the
metallizing process, to be described presently.

Nitrate of silver is liable to ambiguity, and on this subject I
cannot do better than quote what Dr. Paris has stated in the
work already alluded to, vol. ii. p. 241.

" The alkaline phosphates are found to produce precipitates
with silver, analogous in colour and appearance to the arsenite
of silver. This constituted one of the principal points in the
evidence for the defence, on the trial of Donnall for the murder
of Mrs. Downing; and it must be admitted as a valid objection,
if the experiment be performed in the manner just stated ; but
there are other reagents which will immediately distinguish these
bodies, as we shall presently have occasion to state, under the
history of the ammoniuret of silver, as a test for arsenic. The
author has also shown, that there is a mode of so modifying the
application of the present test, that no error or doubt can arise
in the use of it, from the presence of any phosphoric salt. This
method consists in conducting the trial on writing paper, instead
of in glasses ; thus — drop the suspected fluid on apiece of white
paper, making with it a broad line ; along this line a stick of
lunar caustic is to be slowly drawn several times successively,
when a streak is produced of a colour resembling that known by
the name of Indian yellow ; and this is equally produced by the
presence of arsenic, and that of an alkaline phosphate, but the
one from the former is rough, curdy, and flocculent, as if effect-
ed by a crayon, that from the latter is homogeneous and uniform,
resembling a water-colour laid smoothly on with a brush ; but a
more important and distinctive peculiarity soon succeeds, for in
less than two minutes the phosphoric yellow fades into a sad
green, and becomes gradually darker, and ultimately quite
black ; while, on the other hand, the arsenical yellow remains

fermanent, or nearly so, for some time, when it becomes brown,
n performing this experiment, the sunshine should be avoided,
or the transitions of colour will take place too rapidly. It would
be also prudent for the inexperienced operator to perform a simi-
lar experiment on a fluid known to contain arsenic, and on
another with a phosphoric salt, as a standard of comparison."

The ambiguity arising from the use of nitrate of silver has
also been most satisfactorily obviated by Mr. Smithson (Annals
of Philosophy, Aug. 1822). This method consists in converting
the arsenious into arsenic acid, or rather into arseniate of
potash; and Mr. S. observes, " that a drop of a solution of
oxide of arsenic in water, which at a heat of54 , 5° of Fahr. con-
tains not above l-80th of oxide of arsenic, put to nitrate of
potash in the platina spoon and fused, affords a considerable
quantity of arseniate of silver. Hence when no solid particle of
oxide of arsenic can be obtained, the presence of it may be
established by infusing in water the matters contained in it."

1824.] Tests for detecting the Presence of Arsenic. 35

Instead of using a platina spoon, a glass tube, or the bottom of an
oil flask, may be employed ; into either of these, put a little of
the suspected solution, and which has exhibited indications of the
presence of arsenic by other tests ; then drop in a small crystal
of nitre, evaporate the solution to dryness by means of a spirit-
lamp, and afterwards heat it strongly in the same way. Add a
little distilled water to the residuum, dissolve it, and then add
nitrate of silver ; if the solution before heating contained arse-
nious acid, it will now contain arseniate of potash, which will
o-ive a brick red precipitate with the nitrate of silver, and with-
out the intervention of any alkali. From repeated trials, I con-
sider the confirmatory evidence afforded by this experiment as
amounting almost to demonstration. This experiment is ren-
dered shorter, and not less conclusive, by employing the arse-
nious acid and nitre both in the state of powder ; but as the
former is not always procurable after fatal effects have been
produced by it, I have mentioned the solution as affording very
satisfactory results.

I shall now mention the method of confirming the previous
experiments by reducing the arsenious acid to its metallic state.
If the quantity of arsenious acid procurable be very small, then
it is proper to dissolve the whole of it in distilled water, and the
precipitates which are obtained by the action of the various
reagents should be collected and submitted to the metallizing
process ; but if the quantity of arsenious acid be so large that a
few grains, or not less than one grain, can be spared for metalli-
zation, then the precipitates may be rejected, and much trouble
will be spared.

This process is thus recommended to be performed by Dr.
Paris, in his work before alluded to, vol. ii. p. 233 : —

" Mix a portion of the suspected substance in powder, with
three times its weight of black flux ;* put the mixture into a thin
glass tube, about eight inches in length, and a quarter of an inch
in diameter, and which is hermetically sealed at one end. Should
any of the powder adhere to the sides of the tube, it must be
carefully brushed off' with a feather, so that the inner surface of
its upper part may be perfectly clean and dry. The closed end
of the tube, by way of security, may be thinly coated with a mix-
ture of pipe-clay and sand ; but this operation is not absolutely
necessary. The open extremity of the tube is to be loosely
plugged with a piece of paper. The coated end must now be
submitted to the action of heat, by placing it in a chaffing dish
of red-hot coals, for ten minutes, or a quarter of an hour ; when,
if our supposition respecting the nature of the substance has
been correct, metallic arsenic will sublime, and be found lining;
the upper part of the tube with a brilliant metallic crust. The

■ This substance may be said to consist of charcoal in a state of cMrcmcly minute
division, and the subcarbonatc of potash. It is prepared by deflagrating, in a crucible,
two parts of supertartrate of potash with one part of nitrate of potash.

1)2

36 Tests for detecting the Presence of Arsenic, [Jan.

glass tube, when cold, may be separated from its sealed end by
the action of a file, which will enable us to collect and examine
the metallic sublimate. If a portion of this brilliant matter be
laid on heated iron, it will indicate its nature by exhaling in
dense fumes, having a powerful smell of garlic. Another por-
tion should be reserved for future experiments.

" This method of detecting the presence of arsenious acid has
been considered the most decisive, and indeed the only unex-
ceptionable one, but of this we shall speak hereafter ; at present
we have only to observe, that it is very far from being a minute
test ; for Dr. Bostock confesses that where less than three-
fourths of a grain were used, he could not say that the metallic
crust was clearly perceptible ; and Dr. Black appears to have
considered that one grain was the smallest quantity which could
be distinctly recognised by such a process."

This method is unquestionably excellent, but I have found
that the metallization may be very conveniently effected by
means of a spirit-lamp. Indeed it may possibly happen that a
glass tube, such as is requisite for the above process, cannot
be procured at the moment in which it may be wanted ; a
spirit-lamp may also be wanting. I have adopted the fol-
lowing plan : let a piece of tin plate, about an inch long, be
coiled up into a cylinder of about 3-8ths of an inch in diameter,
and if the edges be well hammered, it is not necessary to use
solder. Perforate a cork previously fitted to a vial, and put a
cotton wick through the short tin tube, and the tube through
the cork, the lamp is now complete, and will afford a strong
flame, taking care of course not to prevent the rise of the spirit
by fitting the cork too closely. Instead of a test tube about six
inches in length, which however is certainly much to be prefer-
red, I have employed, with the precautions copied from Dr.
Paris, a common draught vial ; those best adapted for the pur-
pose are called ten drachm vials, for they are long in proportion
to their diameter. In using these vials, the suspected powder
and black flux must not reach the bottom of the vial, for, on
account of its thickness, it will readily break on the application
of heat. The vial, therefore, must be heated laterally, the
arsenic will readily sublime, and will, after the vial has been
divided by a file, if heated in the spirit-lamp, give out the well-
known alliaceous smell. Indeed if the quantity of arsenious
acid be large, the smell which the volatilized metal affords may
be resorted to in confirmation of other evidence ; but it is to be
observed, that it must be mixed with charcoal, or some sub-
stance which reduces it to the metallic state, for arsenious acid,
though volatilized by heat, and exhibiting white fumes, does not
give any smell.

I have now concluded the sketch which I proposed giving,
and, if I mistake not, the use of animal charcoal in the mode
described, will afford some facilities. I hope also that I have,
in some degree, strengthened the evidence which is afforded by

1 824.] Corrections in Right Ascension. 37

using sulphate of copper, and rendered the process of metalliza-
tion less difficult by using common instruments, and such as are
within the reach of every practitioner, or readily procurable by
him. In concluding, I beg to refer the reader to the work on
Medical Jurisprudence, to which I have been so largely indebted,
as one which will afford him much and minute information on a
subject of some difficulty, and of great importance.

Article VIII.

Corrections in Right Ascension of 37 Stars of the Greenwich
Catalogue, together with an Inquiry how far it would he advi-
sable that the Daily Corrections in li.A and North Polar Dist-
ance of the 46 Zero Stars should be computed Annually at the
Public Expence. By James South, FRS.

(To the Editor of the Annals of Philosophy.)

DEAR SIR, Blackman-ttreet, Dec. 18, 1823.

Ha vi ng for some years principally devoted myself to the pur-
suit of practical astronomy, 1 have seen with much regret the
various difficulties which the private observer has to contend
with ; having also severely felt some of them, I have endeavoured
occasionally to diminish them for others : knowing also that
some of these auxiliaries have been used in the most important
observatories in the country, and that to some private indivi-
duals they have proved welcome, in the absence of others hav-
ing stronger claims to confidence, I am induced to publish the
corrections in right ascension of the 37 stars of the Greenwich
catalogue, for every day of the year 1824.

I had indulged a hope (as a reference to this journal two
years ago will prove) that the daily corrections not only in Right
Ascension, but also in North Polar distance, not only of the 37,
but of the 46 Zero stars, would long since have made their
appearance, under the sanction of a Society instituted expressly
for the purpose of promoting astronomical science. As, how
ever, these hopes are not realised, owing probably to the little
want which most of its leading members have of such a publica-
tion, it may be worth while to see whether a case cannot be
made out sufficiently strong, to justify government in having
such corrections computed, at the public expence.

Our inquiry will then be divided into three parts ; first, what
will be the probable benefits resulting from such a publication ;
secondly, what the expence of procuring it ; and lastly, how far
the former is equivalent to the tatter. In doing this it will be
necessary to enter somewhat minutely into the matter, as there
are many individuals, although perfectly conversant with the
principles of astronomy, who have little idea of the routine of
observatory business.

38 Corrections in Right Ascension of [Jan.

The province of the practical astronomer is to determine the
apparent place of all sidereal bodies which come within the
reach of his instruments, and to observe such phenomena as
from time to time present themselves ; in the present instance,
we shall confine ourselves to the former. It is scarcely neces-
sary to mention, that by the place of anybody in the sidereal
heavens is understood its right ascension and north polar dist-
ance ; each is determined generally at the moment in which the
object passes the meridian of the observer, by the aid of instru-
ments fixed in its plane ; the transit instrument (with its
appendage, the clock) giving the former, while the quadrant or
circle indicate the latter.

But by the successive labours of Bradley, Maskelyne, and
Pond, the places of 48 stars have been determined with extreme
accuracy, these we consider as Zero points when we would
assign to any celestial body, its right ascension or north polar
distance. Accordingly the business of the practical astronomer
among us, as far as right ascensions are concerned, is to secure
the meridian passage of each of these stars, or as many of them
as possible, and also of as many other stars, planets, or comets,
as opportunity will allow ; he then finds the error of his clock
by each Zero star, at the time of observation, thence deduces its
mean error at a corresponding time ; he next determines the
clock's daily rate by comparisons with previous observations of
the same stars ; and hence obtains a mean rate. With these
materials he is now prepared, by the aid of a little calculation, to
apply the clock's error to each observed transit, and is thus fur-
nished with the observed right ascension of each sidereal object
at the time of its passing the meridian of his observatory.

Of all these calculations, however, that whereby he arrives at
the error of his clock is by far the most troublesome ; for before
he can find its error by a single star, he must apply corrections
to the star's mean right ascension, brought up to the 1st of Jan.
of the current year; and these he must seek by reference to the
17th and 18th tables of Dr. Maskelyne's ; the first of which
gives him the sum of the corrections for aberration, precession,
and solar inequality of precession. Nine times out often, how-
ever, he has to find the equation by proportional calculation,
and when gotten, it is sometimes positive, sometimes negative.
Having proceeded thus far, he refers to the Nautical Almanac
for the place of the moon's node, and consults Table 18, which
affords him, rarely without calculation, the correction for lunar
nutation; again sometimes a positive, sometimes a negative quan-
tity : he now applies one correction to the other, and procures a
result which, added to or subtracted from the star s mean right
ascension, affords him the star's apparent right ascension at the
time required; and which compared with the observed transit,
presents him with the clock's error, by that particular star.
Thus has he to hunt out corrections for every one of the 36 stars
before lie can convert its observation to any useful purpose; and

1824.] Thirty-Seven Principal Stars. 39

I know by experience, that less than three minutes will not suf-
fice to procure with care, the correction in right ascension for
each star : and he must have little experience, or less candour,
who will not acknowledge that, with all his circumspection, he
has not occasionally taken out a false quantity from a wrono-
column, or applied one correction to the other with a wrong

sign

But it may be said, a reference to preceding observations will
immediately detect the error : not so perhaps ; many days may
have elapsed since a transit of the same star may have been
observed ; or it may be urged, that the amount of error, should
it escape unnoticed, will be such as not materially to invalidate
the result. Now as far as small instruments, such as are usually
stuck out of a window, are concerned, I will concede the point,
for with these, an erroneous computation, amounting to two or
three-tenths of a second, may really do no harm ; but where an
instrument is used, adequate under favourable circumstances, to
assign to any star south of our zenith, its right ascension by a
single observation, accurate to the largest of these quantities, an
error in the calculation of the correction becomes extremely
injurious ; for it may so far vitiate others, as to require many
additional observations to invalidate its force. We shall then,
perhaps, be told, reject it when reduced to the 1st day of the
year ; this may certainly be done, but I hold it a bad principle
to discard any observation, unless posted as bad at the time of
entering it in the rough journal; it leads to temptation which
ought in limine to be checked. Observations, be it never for-
gotten, are not less entitled to our confidence because they are
not always uniform ; and were I asked why the observations
made at our Royal Observatory have acquired the influence they
have over Europe, I should reply, not only because its instru-
ments are superior, but because every observation, good, bad,
and indifferent, which has been entered in the Observatory
Journal, has been honestly recorded in the printed copies.

The remaining process of computing is extremely simple.
When, however, 50 or 60 stars are observed daily, its irksomeness
is quite sufficient ; a circumstance which induced me some time
since to remove as much of the drudgery as could be removed,
by computing a table, in which the clock's daily rate and error
at a particular time of the day being known, its corresponding
error at any given time might be found by inspection.

( To he concluded in our next.)

The accompanying Corrections are computed from Dr. Maske-
lyne's tables, except those of the pole star, which are derived
from its apparent right ascension, given in the Nautical Alma-
nac for 1824. For the mean right ascensions, 1 am indebted to
the kindness of the Astronomer Royal.

Note.— It being generally admitted that something in the shape of an Astronomical
Ephemeris in much needed, I shall publish in the Journal of Science and the Arts for
January next, a list of astronomical phenomena arranged in order of succession for the
first three months of the year l»'i4.

40

Corrections in Right Ascension of

[Jan.

t Pegasi 1

Polaris

a Arictis

a Ceti L

\ldebaran

Capella

Hiccel

£Tauri L Orionis

Mf-in AK7
JH24. i

l. m. s. '

i. m. s. 1

i.in. s.

i. m. s.

1. 1)1. s.

i. m. s.

1. m. s.

i. m. s. |h. m. s.

) 4 11-171

u ss sj-flfl

1 57 16 42

L' S3 5 44 •

I 25 50-01

5 3 4221 j

5 6 511

i 13 1052

) 45 38113

Jan. 1

+ 0-82"

+ 1-09"

+ 1-57"

+ 1-80"

+ 2-32"

+ 3-21"

+ 2-24"

+ 2-69"

+ 2-41"

g

81

0-39

56

79

32

21

24

69

41

3

80

- 031

55

79

32

21

24

69

42

4

79

101

53

78

31

21

24

69

42

5

78

1-70

52

77

31

21

24

69

43

6

77

2-38

51

76

31

21

24

69

43

3

75

3-06

50

76

30

21

23

69

44

8

74

3-74

49

75

30

20

23

70

45

9

73

442

47

75

29

20

23

70

45

10

71

511

45

74

29

20

23

70

46

11

70

582

44

73

28

19

23

70

46

12

69

6-52

43

72

28

19

22

69

46

13

68

7-23

41

71

27

18

22

69

46

14

67

7-93

40

70

26

17

21

69

46

15

66

8-64

39

69

25

16

21

63

46

16

65

9-34

38

6?

25

16

20

68

46

17

64

1005

37

66

24

15

20

68

45

18

64

10-75

35

65

23

14

19

67

45

19

63

11-46

34

64

23

14

19

67

45

20

62

1216

33

63

22

13

18

67

45

21

61

12-83

32

62

21

12

17

66

45

22

60

13-50

30

61

20

11

17

66

• 44

23

59

1417

29

59

19

10

16

65

44

24

58

14-84

28

58

18

09

15

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43

25

57

15-50

27

57

17

08

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64

43

20

56

1617

25

56

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06

14

63

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27

56

16-84

24

54

16

05

13

62

42

28

55

17-51

23

53

15

04

12

62

42

29

54

1818

21

52

14

03

12

61

41

30

53

18-83

20

51

13

02

11

60

41

31

52

19-49

19

50

12

01

10

59

40

Feb. 1

55

2006

17

47

09

2-98

09

58

38

2

54

20-68

16

46

08

97

08

57

37

3

52

21-30

14

44

07

95

07

55

36

4

51

21-92

13

43

05

94

06

54

35

5

50

2251

11

42

04

92

05

53

34

6

48

23-15

10

40

03

91

04

52

34

7

47

23-77

09

39

02

89

03

51

33

8

46

24-39

07

38

01

88

02

49

32

9

45

25-00

06

37

1-99

86

00

48

31

10

45

2555

05

30

98

84

1-98

47

30

11

44

26-10

03

34

96

82

97

45

29

12

44

26-64

02

33

95

80

95

44

27

13

44

2719

01

31

93

78

94

43

26

14

43

27-73

1-00

30

92

76

92

41

25

15

43

28-28

0-98

29

91

74

91

40

24

1(5

42

28-83

97

27

90

72

89

38

23

17

42

29-37

96

26

88

70

87

37

21

18

41

2991

94

25

86

68

85

36

20

19

41

30-46

93

23

85

66

84

34

19

20

41

30-91

92

22

83

64

83

33

18

21

40

3136

91

20

82

62

81

31

16

22

40

31-81

90

19

80

60

80

30

15

23

40

32-26

89

17

78

58

78

28

14

24

40

32-71

88

16

77

56

77

27

13

2.5

39

331G

S7

15

75

55

75

25

11

26

39

33-01

SO

13

74

53

74

24

10

27

39

34-00

85

12

72

51

72

22

09

28

39

3451

84

11

71

49

71

21

07

29

38

34 96

83

09

70

47

69

19

06

1824.]

Thirty-Seven Principal Stars.

41

Sirius

Castor

Procyon

Pollux 1

» Hydra Regulus

3 Leonis \$ Virginis SpicaVirg.

McanAK) 1

. m. s. 1

. m. s. 1

. in. f. 1

. 111. s. 1

i. in. s. li. m. s. 1

. m. s. !li. in. s. 1

i. m. s.

1H24. J 1

:ir 28-49 ?

23 21-46

7 30 532 ',

34 32-18 9 18 56449 ft8 WH^l 40 4/3 11 41 31-86 13 1556-07

Jan. 1

+ 2'32"

¥ 2-91"

f 2-41"

+ 2-80"

4- 2-01" + 203"

f 1-50"

+ 1-41"

-!- 0-84"

2

33

93

42

82

06

06

53

44

87

3

33

94

44

83

08

09

56

48

91

4

34

96

45

85

11

11

60

51

94

5

35

97

47

86

13

14

63

55

98

6

35

99

48

88

15

17

66

58

101

7

36

301

50

90

17

20

69

62

04

8

37

02

52

91

19

23

73

65

08

9

37

04

53

93

22

25

76

68

12

10

38

06

55

95

24

28

79

71

15

11

38

07

56

96

26

30

82

74

18

12

38

08

57

97

28

33

85

77

22

13

39

09

57

98

30

35

88

79

25

14

39

10

58

99

32

37

91

82

28

15

39

11

59

300

34

40

94

85

32

16

39

11

59

01

36

42

96

87

35

17

39

12

60

02

37

44

99

90

38

18

40

13

61

03

39

46

2-02

93

42

19

40

14

62

04

41

49

05

96

45

20

40

15

63

05

43

51

08

99

48

21

40

15

63

06

44

53

11

2-02

51

22

40

16

64

06

46

55

13

o4

54

23

40

16

f»4

07

47

57

16

07

58

24

39

17

65

07

49

59

18

10

61

25

39

17

C5

08

50

61

20

12

64

26

39

18

66

09

51

63

23

15

67

27

39

18

66

09

53

64

25

18

70

28

38

19

67

09

54

66

28

20

74

29

38

19

67

10

55

68

31

23

77

30

38

20

68

11

57

70

34

26

80

31

37

20

68

11

58

71

36

28

83

Feb. 1

35

20

67

11

58

72

39

28

89

2

34

20

67

11

59

73

41

30

91

3

33

20

67

11

60

75

44

33

94

4

33

19

67

11

61

76

46

35

96

32

19

67

11

62

77

49

37

2-00

6

31

19

67

11

62

79

51

40

02

7

31

19

66

11

63

80

54

42

04

8

30

18

66

11

64

81

56

44

or

9

29

18

66

11

65

83

57

47

09

1G

28

17

65

10

65

84

59

49

11

11

27

17

65

10

66

85

61

51

14

12

26

16

64

09

66

86

63

53

16

13

25

15

63

09

67

87

65

55

19

14

24

15

63

08

67

88

67

57

21

IS

23

14

62

08

67

88

68

59

24

16

22

13

61

07

68

89

70

60

26

17

21

13

61

06

68

90

72

62

29

u

20

12

60

06

68

91

74

64

31

11

1 19

11

59

05

69

92

76

66

34

2(

1 18

10

58

04

69

92

77

67

36

21

16

09

57

03

69

93

78

69

38

25

! 15

08

56

02

69

93

80

70

40

2:

1 13

07

56

01

69

94

81

71

42

2'

1 12

06

55

00

69

94

S2

7S

44

2.

> 11

05

54

00

69

94

83

73

46

21

J 09

04

53

2-99

69

95

84

75

49

2'

1 07

03

52

98

69

95

85

76

51

2

i 06

02

52

97

69

96

87

77

53

2

» 05

01

51

96

69

96

88

79

55

42

Corrections in Right Ascension of

Arcturus

2Libr«e i

«Cor.Bor.

a Serpent

An tares

aHerculis

aOpliiuclii

a Lyra

y Aquilx

Mean AR 1

im. i

i. in. s.

h. m. s. 'h. m. s.

h. m. ».

ll. 111. s.

h. in. s.

li. m. s.

li. m. s.

h. in. 5.

14 7 38-33

14 41 963

152714-45

1535 3647

16 IS 27-91

17 6 37-72

17 2646-24

1830 5S-y9

1937 53 68

Jan. 1

+ 0-55"

+ 0-42"

- 0-04"

+ Oil''

+ 0-03"

- 0-29"

-0-31"

- 1-01"

_ 0-33"

2

58

45

01

14

06

27

29

00

32

3

61

49

+ 02

17

09

25

27

099

31

4

64

52

05

20

12

22

'25

98

31

5

67

55

08

23

15

20

23

97

30

6

70

59

11

25

18

18

21

96

29

7

73

62

15

28

21

16

19

94

28

S

76

65

18

31

24

14

17

93

28

9

79

69

21

34

27

11

15

92

27

10

82

72

24

37

30

09

13

91

26

11

85

75

27

40

33

07

11

89

25

12

89

78

30

43

36

04

09

88

24

13

92

82

33

46

39

02

06

86

23

14

95

85

36

49

42

+ 01

04

85

22

15

99

88

39

52

45

03

02

83

21

16

1-02

91

43

55

48

05

00

82

20

11

06

94

46

58

52

08

-1- 02

80

18

18

09

98

49

61

55

10

05

79

17

19

12

101

52

64

58

12

07

77

16

20

15

04

55

67

61

15

09

75

15

21

18

07

58

70

64

If

11

73

14

22

21

11

61

73

68

20

14

71

12

23

24

14

64

76

71

23

16

69

11

24

27

18

68

79

75

26

19

67

09

25

30

21

71

82

78

28

21

65

08

26

34

25

74

85

82

31

24

62

06

27

37

28

77

89

85

33

26

60

05

28

40

32

81

92

88

36

29

58

03

29

43

35

84

95

92

3!)

31

56

02

30

46

39

87

98

95

42

34

54

00

31

49

42

90

101

98

45

37

52

+ 02

Feb. 1

52

44

94

04

1-02

48

40

49

03

o

55

47

97

07

05

51

43

47

05

3

58

51

101

10

09

54

46

44

07

4

61

54

04

13

12

56

48

42

08

5

64

58

07

16

16

59

51

39

10

6

67

61

10

19

19

62

54

36

12

7

71

64

14

23

23

61

56

34

13

8

74

68

17

26

26

67

59

31

15

9

. 77

71

20

29

29

70

62

29

17

10

80

74

23

32

32

73

85

26

19

11

83

77

26

35

36

76

68

24

21

12

86

80

29

38

39

79

70

21

23

13

89

83

32

41

43

82

73

18

25

14

92

86

35

44

46

85

76

16

27

15

95

89

39

47

50

88

78

13

28

16

97

93

42

50

53

90

81

11

30

17

00

96

45

53

57

93

84

08

32

18

03

99

48

56

61

96

87

05

34

19

06

2-02

51

59

64

99

90

02

36

20

08

05

54

62

67

1-02

93

+ 01

38

21

211

07

56

64

70

04

95

03

40

2*

13

10

59

67

74

07

98

06

42

23

15

12

62

69

77

09

100

09

45

24

18

15

64

72

80

12

03

II

47

25

20

17

67

74

83

14

06

14

49

26

22

20

70

77

86

17

08

17

51

27

24

22

73

79

89

20

11

19

53

28

26

25

75

82

93

22

13

22

56

29

29

28

78

85

96

25

16

25

58

* Mean AR of 1 « Libra 14* 40' 58-21".

1824.]

Thirty' Seven Principal Stars.

43

x Aquilae

S Aquilae '.

* aCapric.

a C'ygni

> Aquarii

■'omalliaiit

■ Pegasi :

■Androui.

Mean AH 1 1

i. m. s. t

. n>. s. 1

1. m. s.

1. 111. 9-

i. m. 9.

1. 111. s.

1. 111. 9. II. III. 9.

18-24. • 1

9 4211-881

9 46 40-231

■0 8 17-02:

>035 26-21

!1 56 44 67

22 47 5434 22 56 017:

"3 59 18-67

Jan. )

- 0'30''

- 0-27"

- 0-09"

- 103"

+ 0-22"

+ 055"

+ 0-39"

+ 0-70"

2

29

26

08

04

21

54

38

68

3

29

26

08

04

21

53

37

67

4

28

25

07

05

20

52

36

65

h

28

24

06

05

20

51

35

64

6

27

24

06

06

19

50

34

62

7

27

23

05

06

19

49

34

61

S

26

23

05

07

18

48

33

59

9

26

22

04

07

IS

47

32

58

10

25

21

03

08

17

46

31

57

11

24

20

02

08

17

45

30

56

12

23

19

01

08

17

44

30

55

13

21

18

00

08

17

44

29

54

14

20

17

+ 0-01

07

17

43

29

53

15

19

16

02

07

17

42

28

52

16

18

15

02

07

17

41

28

51

n

17

13

03

07

17

40

27

49

18

16

12

04

06

16

39

27

48

19

14

11

05

06

16

39

26

47

20

13

10

06

06

16

38

25

46

21

12

09

07

06

16

38

25

45

22

10

07

09

05

16

37

24

44

23

09

06

10

05

17

37

24

43

24

07

04

11

04

17

36

23

42

25

06

03

13

04

17

36

23

41

26

05

02

14

03

17

36

22

40

27

03

00

15

03

17

35

22

38

28

02

+ 01

16

02

17

35

31

37

29

01

03

18

02

18

34

21

36

30

+ 01

04

19

02

18

34

20

35

31

03

06

20

01

18

34

20

34

Feb. 1

04

06

22

00

19

34

20

33

2

06

08

24

0-99

19

34

20

32

3

08

10

25

98

19

34

20

32

4

10

11

27

97

20

33

19

31

5

11

13

28

95

20

33

19

31

6

13

15

30

94

20

33

19

30

7

14

16

32

93

20

33

19

30

8

16

18

34

92

21

32

13

29

9

18

20

35

90

21

32

18

28

10

20

22

37

88

22

32

18

27

11

22

24

39

87

23

32

18

27

12

24

25

41

85

24

32

18

26

13

26

28

43

84

25

33

18

26

14

2S

30

45

82

.26

33

18

25

15

30

32

47

81

27

33

18

25

If

33

34

48

79

27

33

19

24

17

35

S3

50

77

28

33

19

23

li

37

37

52

75

29

34

19

23

If

39

39

54

74

30

34

19

22

2t

41

41

56

72

31

34

19

22

21

43

43

58

71

32

35

20

21

Of

45

46

60

69

33

35

20

21

2J

47

47

62

67

34

36

81

81

24

49

49

64

66

35

86

21

21

2£

50

51

66

64

36

37

81

20

2)

52

53

67

62

36

37

88

20

21

54

55

69

CO

37

38

22

20

2f

56

58

71

59

38

88

23

19

2£

58

60

73

57

39

89

23

19

♦ iMean Alt of 1 « Capricor. 20h T 53-23".

44

Corrections in Right Ascension of

[Jan.

r Pegasi

Polaris

x Arielis

a Cetl Aldebaran

Capella

Rigel

(JTaurl a Orionis

Mean AR 1 h
1824. )

. m. s. 1
4 11-170

. m. e. 1

58 266 1

-35-41"
3574
3607
36-40

. ill. s. 1
57 1642:

. m. s. h. m. s. 1
53 5-44 4 25 50-01 {

i. m. s.
3 42-21 1

+ 2-45"
43
41
39

i. m. s. 1
6 5-11!

l. m. s. h. m. s.
. 15 1052 5 45 3893

March 1 -
2
3
4

• 0-38" -
38
38
38

+ 0-82"
81
80
79

+ 1.08"
07
05
04

+ 1-69"
67
66
64

+ 1-68"
66
64
63

+ 2-1"
16
14
13

+ 2-05"

03

01

1-99

98

5

38

36-73

78

02

63

36

61

11

6

38

37-06

77

01

61

34

59

09

97
95
94

7
8

38

37-39

76

0-99

60

32

57

07

38

37-72

75

98

58

30

55

06

9

38

38-05

74

97

55

28

54

04

92
91

10

38

38-38

73

96

54

25

52

02

1]

38

38-71

72

95

53

23

50

00

89

12

39

38-92

71

94

52

21

48

1-98

87

13

39

39- 12

71

93

50

18

47

96

86
84

14

40

3933

70

92

49

16

45

95

15

40

39-53

70

91

47

14

43

93

83

16

41

3974

69

90

46

12

41

91

81

17

41

39-95

69

89

44

09

40

89

79

18

42

40-15

68

88

43

07

38

88

78

19

42

40-36

67

87

41

05

36

86

76

20

43

40-56

67

86

40

02

35

84

74

21

43

40-77

66

85

38

200

33

82

72

22

44

40-85

66

84

37

1-98

31

80

70

23

45

40-93

65

83

35

96

30

79

69

24

45

4101

65

83

34

94

28

77

67

25

46

41-09

64

82

33

92

27

75

66

26

47

4117

64

81

31

90

25

74

64

27

48

41-25

64

80

30

88

24

72

63

28

4!)

41-33

63

80

28

86

22

70

61

29

50

41-41

63

79

27

83

21

68

60

30

51

41-49

62

78

25

81

19

67

58

31

51

41-56

62

77

24

79

17

65

57

— *

Sirius

Castor

Procyon

Pollux

a Hydrse

Kcgulus

(3 Leonis

(3 Virginis SpicaVirg.

Mean AR 1
1824. |

h. in. s.
6 37 23-49

b. «i. s.
7 23 21-46

li. m. s. 1
7 30 S-32

h. m. 8.
7 34 32-18

h. m. s.
9 18 56-44

h. m. s.
9 58 5957

h. in. s.
11 40 4-73

li. in. s.
114131-86

ll, 111. 8.

1315 56-07

March 1

+ 2-04"

+ 300"

+ 2-50"

+ 2-95"

+ 2-69"

+ 2-96"

+ 2-89"

+ 2-80"

+ 2-57 "

2

02

2-99

49

94

69

96

90

81

59

3

01

97

48

92

68

96

91

82

61

4

1-99

96

47

91

68

96

92

83

63

5

97

94

46

90

67

96

93

84

64

6

96

93

45

89

67

97

94

85

66

7

94

91

43

87

66

97

95

86

68

8

92

89

42

86

66

97

96

87

70

g

91

88

41

85

65

97

97

88

72

10

89

87

40

83

65

97

98

89

74

11

87

86

39

82

64

97

99

90

76

is

85

84

38

80

63

96

3-00

91

78

IS

1 83

83

36

79

62

96

00

91

79

14

I 82

81

35

77

62

95

01

92

81

u

i 80

80

34

76

61

95

01

93

82

K

i 78

78

3.3

74

60

94

02

93

84

1'

r 76

77

31

72

59

94

02

94

85

It

I 75

75

30

71

58

93

03

95

87

1!

1 73

73

29

70

58

93

03

95

88

2(

) 71

71

27

68

57

92

04

96

90

2

69

69

26

66

56

92

05

97

92

2'

) 67

67

24

64

55

91

05

97

93

2

I 65

66

23

63

54

91

05

97

94

2

I 63

64

21

61

53

90

05

97

95

2

3 61

62

20

60

52

89

05

98

96

2

6 59

61

18

58

51

89

05

98

98

2

7 57

59

16

56

50

88

06

98

99

2

8 55

58

15

55

49

87

06

98

300

2

9 53

56

13

53

48

87

06

99

01

3

51

54

11

52

47

86

06

99

02

3

1 49

52

09

50

46

85

06

99

03

1824.]

Thirty-Seven Principal Stars.

45

Mean AR )
1824. )

March 1

2

3

4

6

6

7

8

9

JO

11

IS

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

Arcturus

2 a Libra;

oCor.Bor.

a Serpent

h. m. s.

ll. 111. s.

Ii. in. s.

h. m. s.

14 7 38-33 14 41 9'63

1ft 27 14 45

1ft 35 3647:

+ 2-31"

+ 2-31"

+ 1-81"

+ 1 -88" i

33

34

84

91

36

36

87

93

38

39

90

96

40

41

93

99

43

44

96

2-01

45

46

98

04

47

49

201

07

49

52

04

10

52

55

07

12

54

57

10

15

56

59

12

18

58

62

15

20

60

64

17

23

62

66

20

25

64

68

22

28

66

71

25

30

67

73

27

33

69

75

30

36

71

78

32

39

73

80

35

41

75

82

37

43

76

84

40

46

78

86

42

48

80

88

44

50

81

90

46

52

83

92

49

55

85

9)

51

58

86

97

53

60

88

99

56

62

90

3-01

58

64

Antares |aHerculis aOphiuchij a Lyra

li. m. p. H m. s. ill. m. s. Ii. m. s.
1ft 35 3047:16 18 37-91 17 6 3772 1 7 26 46-24 18 3058-99

1-99'
2-02
05
09
12
16
19
22
26
29
32
35
38
41
44
47
50
54
57
60
63
66
69
72
75
78
81
84
87
90
93

+ 1-28"
31
33
36
38
41
43
46
49
52
54
57
61
64
67
70
74
77
80
84
87
90
92
95
98
200
03
06
08
11
14

+ 1

19
22
25
28
31
34
37
40
43
46
49
52
55
58
61
64
67
69
72
75
78
81
84
87
90
93
95
98
201
04
07

• 0-28"
31
34
37
41
44
47
50
54
57
60
63
67
70
74
77
SO
83
87
91
94
97

101
04
07
10
13
17
20
24
27

y Aquilae

li. m. s.
193753-68

0-60"
63
65
68
70
73
75
78
81
84
86
88
91
93
96
98
101
03
06
08
11
14
16
19
22
24
S7
29
32
35
38

a A.ju chi-

Aquilae

2 aCapricor

a Cygni

a Aquarii

1'oni, i! haul

a Pegasi

aAndiom.

Mean AR)

li m. s.

li. in. s.

h. m. s.

ll. 111. s.

ll. m. s.

h. Dl. s.

h. in. s.

111. m. s.

1824. i

19 4211-88

19 46 40-23

20 8 17-02

203ft 26-21

21 56 44-67

22 47 54-34

22 50 o-i;

23 59 18 67

March I

+ 0-60"

+ 0-62"

+ 0-75"

- 0-55"

+ 0-40"

+ 0-39"

+ 0-23"

+ 0-19"

2

62

64

77

53

41

40

24

19

3

65

67

80

50

43

41

25

19

4

67

69

82

48

44

42

25

19

5

70

72

85

45

45

43

26

19

6

72

74

87

43

46

44

27

19

7

75

76

90

40

48

45

28

19

8

77

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92

38

49

46

29

19

9

80

81

95

35

50

47

29

19

10

82

83

97

32

52

48

30

19

11

85

86

1-00

30

53

49

31

19

12

88

88

02

27

55

50

32

19

13

90

91

05

24

56

52

33

20

14

93

93

07

22

58

53

34

20

15

95

96

10

19

60

54

35

21

16

98

98

12

16

61

56

36

21

17

1-00

101

15

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63

57

37

22

18

03

03

17

11

64

58

39

22

19

05

06

20

08

66

60

40

23

20

08

08

22

05

68

01

41

23

21

11

11

25

02

70

63

42

24

22

14

14

28

+ 01

72

65

43

25

83

17

17

31

04

74

66

45

26

24

19

19

38

08

76

68

46

27

25

22

22

36

11

78

69

48

28

26

25

25

39

14

80

71

49

29

27

28

28

42

17

82

73

51

30

28

31

31

44

20

84

75

52

31

29

33

33

47

23

86

76

54

32

30

36

36

50

27

88

78

55

32

31

39

39

53

30

90

79

57

34

■

46 Prof, dimming on a new Thermoelectric Instrument. [Jan.

Article IX.

Description of a New Thermoelectric Instrument. By the Rev.
J. Gumming, Professor of Chemistry in the University of
Cambridge.

(To the Editor of the Annals of Philosophy.)
MY DEAR SIR, Cambridge, Dec. 20, 1823.

Whatever contributes to confirm the close analogy which
subsists between the electricity excited by heat and that by
galvanic action, will, I conceive, be acceptable to those who
take an interest in this subject. For this purpose, I have con-
structed an instrument, the description of which you will oblige
me by inserting in the next number of the Annals of Philosophy.
It exhibits the rotation of a wire round a magnet, and its deli-
cacy is such that when excited by the thermoelectricity of a
silver and platina wire, each of l-22d inch diameter, it revolves
between 30 and 40 times in a minute ; if, instead of these wires,
a pair of galvanic plates of half an inch in diameter be used, the
rotation is rather more rapid.

1 am, my dear Sir, very truly yours,

J. CUMMING.

A B, a cylindrical magnet.

abed,* glass tube containing mercury, cemented on the top

of the magnet.

CDEF, a brass wire poised by a needle point passing
through I, and resting upon an agate cemented upon the
magnet.

1824.] MM. Dumas and Pelletier on Organic Salifiable Bases. 47

C G, F H, platina points soldered to the wire C D E F.

K L, a cylindrical piece of wood, having a perforation to admit
the magnet, and a circular groove containing mercury, in which
the points G and H revolve.

ef, a copper wire passing through the bottom of K L, and
communicating with the mercury in the groove.

M O, cups filled with mercury.

P N, wires passing from the positive and negative ends of the
exciting apparatus.

The current from the positive pole P ascends through the
magnet to I, descends down D G, EH, into the mercury in the
circular groove, and from thence through the copper wire e /',
into the cup M, connected with the negative pole by the wire N.

Article X.

On Organic Salijiable Bases. By MM. Dumas and Pelletier.*

The following is the analysis of these compounds given by
these chemists :

Carbon.

Azote.

Hydrogen.

6-66
6-22
6-52
6-54
8-54
7-77
7-01
5-91
4-81

Oxygen.

75-00
76-97
75-04
78-22
66-75
64-57
72-02
68-88
46-51

8-45
9-02
7-22
8-92
5-04
4-30
5-53
7-21
21-54

10-43

7-79

11-21

6-38

19-60

22-95

14-84

18-00

27-14

MM. Dumas and Pelletier calculate that quinina is consti-
tuted of

Atoms.

Carbon 60 or in 100 parts nearly 75*38

Azote 3 8-72

Hydrogen 30 6-15

Oxygen 3 9'85

96

100-00

If, however, we calculate the weights of the atoms as given
by Dr. Thomson, Dr. Henry, and Mr. Brande, it will be found
that the number of atoms which enter into the constitution of

• From the Annalcs de Chimie et de Physique, vol. xxiv. p. 191.

48 MM. Dumas and Pelletier on Organic Salifiable Bases. [J A n .

this, and probably the other substances, are much fewer, and
the calculated result is rather nearer that obtained by experiment.

Carbon. .. 20 atoms 6 x 20 = 120 or in 100 parts 75-00

Azote 1 = 14 8-75

Hydrogen. 10 =10 6-25

Oxygen.. 2 8 x 2 = 16 10-00

"33" 160 100-00

In concluding, the authors observe, that the results of the
analyses of the substances in question are equivalent to

Carbonic acid. Azote.

Quinina 100 6-1

Cinchonia 100 5-0

Strychnia 100 4-9

Narcotin 100 4-5

Brucia 120 5-0

Morphia 100 3-2

Veratria 100 3-2

Emetin 100 3-1

Cafein 100 20-0

With respect to the last mentioned substance, MM. Dumas
and Pelletier observe, that no particular memoir has as yet
appeared upon it. It was discovered in 1821 by M. Robiquet,
in his researches to discover quinina in coffee. The authors of
this paper obtained the same principle about the same time, but
the priority is due to M. Robiquet. The properties of cafein are
stated to be, that it is white, crystalline, volatile, and but slightly
soluble.

The method of analysis adopted was that suggested by Gay-
Lussac ; the peroxide of copper employed was prepared by cal-
cining the nitrate at a dull red heat; it was then carefully
washed, and again heated at the same temperature to expel the
moisture ; and before use it was moderately heated in a platina
crucible, and weighed while still warm.

MM. Dumas and Pelletier adopt the specific gravity of
gases as determined by Dulong and Berzelius, and their calcu-
lations are founded on the weights of atoms given by the same
chemists.

1824.] M, Rose on Felspar, Albite, Labrador, fyc. 49

Article XI.

On Felspar, Albite, Labrador, and Anorthite.
By M. Gustavus Rose.*

Some differences I had found in the angles of crystals
described hitherto as felspar, induced me to examine them with
greater accuracy. From my observations, it results that four
different species, which differ as much in their form as in their
chemical composition, had been united under the common name
of felspar ; it is true that there is a great analogy in their crys-
talline forms.

Among these species, that which will retain the name of
felspar, KS J + 3AS 3 , is the one met with most frequently.
Under that name must be classed the adularia from St. Gothard,
vitreous felspar from Vesuvius and from Siebengebirge, the
amazon-stone, the felspar from Friedrichwarn, in Norway, which
had been taken for labrador, the felspar from Baveno, from
Carlsbad, from Fichtelgebirge, and in general the greater part
of what Werner has called common felspar.

The second species called albite (cleavelanditef) N S 3 + 3 A S*
is not so common as felspar. We are indebted to M. Eggerts
for the first notice of this substance; he examined a radiated
variety of it from Finbo and from Broddbo, near Fahlun.
Since, MM. Hausmann and Stromeyer have also found it in a
rock from Chesterfield in North America, and M. Hausmann
named it Kieselspath. M. Nordenskiold found the same sub-
stance in a granite from Kimito, near Pargas, in Finland ; and
lastly, M. Ficinus in a granite from Penig, in Saxony ; but all
these varieties were not regularly crystallized. The crystals of
the same substance which 1 have had an opportunity of seeing, are
the crystals from Dauphiny, which Rome de LTsle had described
under the name of schorls blancs, and which afterwards Haiiy
took for felspar ; the crystals from Salzbourg and the Tyrol, de-
scribed as adularia; the crystals from Kerabinsk in Siberia,
from Arendal in Norway, from Prudelberg near Stirschberg in
Silesia; as well as many other crystals from different localities.
The third species is the labrador (labrador-felspar) which
Klaproth had already analyzed and separated from felspar ; the
external characters of this substance had, however, prevented
mineralogists from making a distinct species of it. From the

• Translated (with some omission*) from the Annales tie Chimie et de Physique,
tome xxiv. p. 5.

UMIIC AtlVi p. J.

* This name (cleavelandite) was proposed for albite by 3Jr. Brooke, but the origi-
nal term has been preserved in this translation.

New Series, vol. vn. e

50 M. Rose on Felspar, [Jan.

analysis of Klaproth, M. Berzelius has found that the formula
was N S 3 + 3 C S 3 + 12 A S.

The fourth species is the scarcest of all ; I have only met with
it in small groups of crystals in blocks of carbonate of lime, which
are found near Vesuvius. I have found that their chemical
formula was MS + 2CS + 8AS, and I have given them
the name of anorthite.

I shall now describe the principal properties of these four
species. In the description of the crystals I have only given
the primitive form, the signs of the secondary planes, and the
principal angles. I have thought it useless to describe more
minutely the secondary crystals.* The figures I have given,
especially when compared with their signs, are perfectly suffi-
cient to form an exact idea of the relative situation of these
planes, and of the parallelism of the edges. The signs of the
secondary planes are given according to the method of Haiiy,
and I have calculated them from the angles of the primitive
form, which I have measured with as much exactness as possi-
ble, by means of spherical trigonometry, and by the parallelisms
of the edges. But the primitive forms of these species beina;
doubly oblique prisms, the theory of which is not yet perfectly
known, their determination depends on five measurements, while
the determination of oblique rhombic prisms depends only on
two : it is for that reason that I can only consider the angles I
have given as approximations not very far from the truth.

The specific gravity has been determined with care. When I
had only small crystals to examine, I weighed some of them in
a small flask of glass, the weight of which both in water and in
air was subtracted from the weight of the flask containing the
small crystals, and weighed under the same circumstances. I
have given the temperature of the water I used in my experiments.
I have not reduced my results to the same temperature, because
they would be but very little altered by that reduction.

The hardness of all the species described is less than that of
quartz, and differs but little from that of felspar. Albite has in
general appeared to me to be the hardest, and labrador the
softest.

First Species. — Felspar.

The system of crystallization is, according to M. Weiss, bino-
singulaire. The primitive form is an oblique rhombic prism, in
which the ratio of the three dimensions which are perpendicular
to each other, and equal to the diagonals of the section perpen-
dicular to the lateral edges, and to the length of one of these

edges is — */ 13 : \f 3-13 : V 3.

The chemical formula is, according to Berzelius, KS J +

• The figures of crystals are not all given in the translation.— Edit,

ANORTBITM.

Fagt 51.

Engraved for the Annalj of Fhilewrhy. rbrJiaMivm.u-adockkfoy. Jan.i$24

1824.] Albite, Labrador, and Anorthite. 51

3 A S s . If we calculate from this formula the proportion of the
constituent parts, we find that 100 parts of felspar contain

Silex 65-94

Alumina ] 7-75

Potash 16-31

Observations. — Although felspar is common, yet it is rarely-
met with in such perfectly brilliant crystals as are necessary
for measurement by the reflecting goniometer The collection
of minerals in the University of Berlin, which is extremely rich
in crystals of felspar, does not contain a specimen the crystals of
which could have been measured by that instrument. The best
for that purpose with which I am acquainted are the cry stals of
glassy felspar from Vesuvius, and I have measured the angles of
some which differ a little from those given by M. Weiss. I have
found for instance the obtuse incidence of the lateral planes of
the primitive to be 119° 18', and that of the base of the primitive
upon one of the lateral planes 1 12° 14^*. These measurements,
however, I did not consider as sufficiently exact to ground my
calculations upon.

I was rather surprised by what I found to be the specific gravity
of the felspar of Baveno. I had weighed it several times, and
1 had chosen not only the hemitrope crystals which are so fre-
quently met there, but also simple crystals which are perfectly
pure, and did not appear to contain any foreign substance. The
results I obtained were always the same, and I was induced to
think that the composition of the crystals of Baveno differed from
that of felspar, and that since the crystallisation was perfectly
the same in both, some isomorphous principle was replaced by
another. I, therefore, analyzed a crystal from Baveno. In
fusing it with carbonate of potash, and in treating it in the
usual manner, I found the proportion between the silex and
the alumina exactly the same as that which exists in common
felspar; so that though I had not separated the potash, I
thought I had no reason to suppose the composition different
from other felspars.

Second Species.— 'Albite.

The primitive form of albite is a doubly oblique prism (Plate
XXV), figs. 1,2. The planes M and T of which are inclined

_- _ 1 /»_■_—»—_—_--_ . 1 - — _ _• --_ - - ______

. perpendicular to the planes M and T is an oblique-
angled parallelogram, fig. 2, the obtuse angle of which is divided
by a plane / produced by a decrement of two rows along the

• Mr. W. Phillips gives fur the same angles 119° 20' and 11 2° 5'.

E2

52 M. Rose on Felspar, [JAN.

edge G, into two angles of 60° 8' and 57° 45", the first of which
has one of its sides situated in the plane M, and the second, one
of its sides in the plane T. The section perpendicular to the
planes M and P is an oblique-angle parallelogram, the obtuse
angle of which is divided by the plane n, produced by a decre-
ment by one row on the edge B, iuto two angles of 46° 5' and
47° 31'; the first of which corresponds to the edge of the paral-
lelogram situated in the plane P ; the other to the edge of the
parallelogram situated in the plane M.
The planes I have observed are

PMT G* G 4 a HAAB C C (see figs. 3, 4).

I x f y x n o g

Incidences.*

TonM' 117° 53'

Ton/ 122 15*

Moa/ 119 52*

Monz 149 12

lonz 150 40

M'on/ 148 30

T on/ 149 23

PonT 115 5*

Pon/ 110 51*

Pono' 122 23*

Mono' 112 11

P on g 150 5

Mong 100 52

PonM 86 24

Pon« 133 55

P on y 97 37

T on y 134 32

Ton*' 110 29

Pons' 127 23

Plane Angles of the Primitive Form.

Those of plane P 119° 12' and 60° 8'
M 116 35 63 25

T 99 45 80 15

The crystals of albite are frequently or almost always met
under the form of hemi tropes. t These hemitropes are formed

• I have marked* the angles from which the others are calculated.

+ I found, however, afterwards, that the crystals of St. Gothard, the prisms of
which are so short that the planes of one of the summits meet those of the Other, are
very likely albite : they are met commonly in simple crystals, and seldom in hemi-
tropes. Their planes were not sufficiently brilliant to be measured ; but it is likely that
they were albite, since, when digested in hydrochloric acid, they were not decomposed.

1824.] Albite, Labrador, and Anorthite. 53

when two crystals are so joined to each other that the upper plane
of the one is applied upon the inferior plane P' of the other, in
the manner exhibited by fig. 3. The two crystals have Gene-
rally the same size -however all the differences which are known
to occur in the hemitropes are also met with in this substance ;
frequently one of the crystals is only visible by a narrow line on
the plane P of the other. A third crystal is often applied on the
second; and a fourth upon the third, &c. The hemitropes
attached to the matrix present always the same end upwards,
and that corresponds to the upper part of fig. o.

This substance can be cleaved parallel to every plane of the
primitive ; the cleavage parallel to P is the most brilliant. The
colour of the crystals is white or reddish-white ; the crystals are
translucent or transparent, either wholly or in part as in those of
Kerabinsk.

The specific gravity will be found in the following table :

Locality.

Weight gram. Sp. gr. Tern, water.

Hemitrope crystals
Hemitrope crystals

Kerabinsk
Kerabinsk

4-808 2-608 20° R.
12-711 2-6175 21i

Id. reddish-white

Arendal

3-692 J 2-619 17
3t92 \2-614 174-

The specific gravity has been found before by

Eggertz, that of Finbo 2*612

Eggertz, that of Broddbo 2-619

Nordenskiold, that of the red albite

from Kimito 2-609

Ficinus, that of the albite of Penig. . . 2-50

The result of an analysis of crystallized albite from Arendal,
decomposed by means of carbonate of potash, is

Silica 68-46 which contains oxygen 34-43^ 12

Alumina 19-30 9-01 3

Lime 0-68

Oxide of iron 0-28

Magnesia

Loss 1 1-27 taken as soda 2-88

Another analysis in which I had precipitated the alumina with
carbonate of potash, gave the following result:

Silex G8-60

Alumina, with a little oxide of iron. . . 19-25

An analysis with carbonate off barytes, gave

54 M. Rose on Felspar, [Jan.

Silex. 68-84

Alumina, with a little oxide of iron and

lime 20-53

Soda 9-12

98-49

If the composition of albite is calculated from the formula
NS 5 + 3 A S 3 , the following proportion of the constituent
parts is found

Silex 69-78

Alumina 18-79

Soda 11-43

Crystallized albite is found at Arendal in Norway, where it is
almost always accompanied with epidote, according to what I
have seen at the place itself, as well as in private collections. It
is found also in the Schmirnerthal, in the Tyrol, with carbonate
of lime in veins of carbonate of lime; at Rohrberg, near
Zell, in veins with quartz, or in gneiss very rich in quartz,
accompanied by rock crystal and carbonate of iron : it is found
in the same circumstances at Gastein, in the country of Salz-
bourg ; at Bareges in the Pyrenees, and at Auris in Dauphiny,
in veins with axinite, anatase, adularia, epidote, asbestus,
with which the albite is sometimes perfectly mixed. As to
the albite of Kerabinsk, in Siberia, the collection of minerals
in the University of Berlin, contains only isolated hemitrope
crystals, which are of a much larger size than the others. Some-
times the plane M is one inch long, while the other hemitrope
crystals are never more than a few lines. At Prudelberg, at
Stonsdorf, near Hirschberg, in Silesia, albite is found with fel-
spar in veins of granite ; the crystals of felspar are flesh-co-
loured, and sometimes covered with crystals perfectly white, or
of the same colour as those of albite. The crystals of felspar of
Baveno are also frequently accompanied by some small whitish
crystals, which commonly are not felspar, but albite.*

Observations. — The crystals of albite are easily distinguished
by their hemitropes, and the re-entering angles formed by the
planes P. If the crystals of felspar were grouped in the same
way, the similar planes of the two crystals would be parallel,
since in felspar the planes M and P are at right angle to each
other, and could never form re-entering angles ; the analogous
hemitrope crystals of felspar, such as those of Carlsbad, can
only be formed as it has been demonstrated by M. Weiss, when
two crystals are grouped, either with their right planes M, or
with their left planes M. So that the faces P of cleavage are
situated on opposite sides in the two crystals, while in albite
the planes P of the two crystals are situated on the same side.

* If the abovt-mentioned crystals of St. Gothard are albite.

1824.] Albite, Labrador, and Anorthite. 55

Albite offers, however, sometimes crystals which are grouped in
a manner analogous to the hemitrope crystals of felspar. They
are joined to each other by their planes M, and consequently
have their planes P on different sides ; but in this case the two
crystals are attached by their other faces to other crystals in the
common way ; so that the whole is only an hemitrope formed
by two different hemitropes which are grouped in the same
manner as the two simple crystals which form the hemitrope
crystals of felspar of Carlsbad.

Although albite is found massive, it is always radiated, never
in laminae, and that distinguishes it essentially from felspar.
It may always be admitted, therefore, that the felspar which is
met in this state is not felspar, but albite. The palmed felspar
of Johann Georgenstadt in Saxony, distinguished by Werner, is
among those of this kind the most known in Germany : how-
ever, some doubts may be entertained concerning several speci-
mens of various localities contained in the collection of minerals
at Berlin.

Besides the albite of Arendal, I have analyzed thatofSalz-
bourg. Some circumstances have prevented me terminating the
analysis of it ; however, I have obtained soda, and the same
quantity of silex, as in the analysis of the albite of Arendal.

The sulphate I had obtained, and which I had crystallized
with a great deal of care, gave me crystals perfectly similar to
those of sulphate of soda. When exposed to the atmosphere,
they fall to powder, and treated by the solution of platina, by
tartaric acid, and by sulphate of alumina, they exhibited the
same properties as sulphate of soda. Having mixed a solution
of these crystals with a solution of chloride of platinum in alco-
hol, it remained perfectly limpid, and evaporated to dryness, and
left a mass perfectly soluble in alcohol. A solution of these
crystals into which I had put tartaric acid, retained its
limpidity. In mixing this with sulphate of alumina and alcohol,
I obtained regular octohedrons perfectly well crystallized, which
I consider as sulphate of alumina and soda ; because when
opposed to the atmosphere, they were reduced to a fine powder,
and are thus sufficiently distinguished of sulphate of alumina and
potash, which mixed with alcohol was immediately precipitated
in a state of powder.

In analyzing albite with carbonate of barytes, I have found a
loss of 2-}r per cent. It is undoubtedly soda which suffers this loss ;
this appears to me so much the more likely, for I obtained silex
and alumina in the same proportions as in analyzing albite with
carbonate of potash, and the result was the same in calcu-
lating the proportion of these two bodies from the same chemical
formula. I could not repeat the analysis, because 1 had used
all 1 had of the substance to determine the nature of the alkali
contained in albite, and for the analysis with the carbonate of
potash.

56 M. Rose on Felspar, [Jan.

Third Species. — Labrador.

This substance is very seldom met in regular crystals. There
is only one specimen in the collection of minerals at the Univer-
sity of Berlin ; and although it is possible to determine the form
of it, which shows great analogy with felspar, the angles can-
not be measured. The modifications appear to be the same as
those of felspar. It cleaves easily in two directions, in one of
which the face obtained by cleavage is perfectly brilliant ; the
difference between the degree of brilliancy ©f these two cleav-
ages denotes a difference between labrador and felspar.
Moreover those two cleavages are not obviously at right angles
to each other. I have found their inclination to be 93^° and 864°.
I could not measure more exactly the incidence of these two
cleavages on account of the dulness of one of them. There is a
third cleavage still more imperfect, and which corresponds with
one of anorthite, but not with any of albite.

Thin lamina* of labrador are of a whitish-grey; the fine reflec-
tion of light which distinguishes this substance is given by one
of the cleavages.

The specific gravity of a fragment of labrador (from Labrador,
in America) weighing 10*576 grs. was found, using water at the
temperature of 18° R. = 2-7025.

The specific gravity of a fragment weighing 12-068 gr. from
the same locality, using water at the temperature of 17|° R. =
2-695.

According to Brisson, = 2-692.

According to Klaproth, = 2-690.

Specific gravity of the labrador from Ingremanie, according
to Klaproth, = 2-750.

One hundred parts of labrador from Labrador, and an equal
quantity of labrador from Ingremanie, contain, according to
Klaproth,

Labrador from Labrador. Labrador from Ingremanie.

Silex 55-75 55-00

Alumina 26-50 24-00

Lime 11-00 10-25

Oxide of iron. 1-25 5-25

Soda 4-00 3-50

Water 0-fi0 0-50

99-00 98-50

Berzelius has calculated from these analyses the mineralogical
formula

N S- 1 + 3 C S 3 + 12 A S.

Observations. — Labrador and felspar present similar charac-
ters with the blowpipe ; and for this reason Berzelius was induced
to suppose that the mineral analyzed by Klaproth, under the
name of labrador, was iridescent pareathine, with which it has

1824.] Albite, Labrador, and Anorthite. 57

great analogy of composition. However, an analysis undertaken
by my brother, gave, excepting a greater quantity of alumina,
almost the same results as that of Klaproth. This chemist has
already demonstrated that the iridescent felspar from Friedrich-
warn, in Norway, cannot be ranked in this class ; it is also dis-
tinguished from it by the incidence of the two faces of cleavage
which is equal to 90°. The acids act upon this mineral in a
different manner than upon felspar and albite ; for concentrated
hydrochloric acid, according to Fuchs, entirely decomposes
labrador, and has no action upon felspar or albite.

Fourth Species. — Anorthite.
The primitive form of anorthite is a doubly oblique prism,
fig. 5, 6, in which the planes M and T are inclined at an angle
of 117° 28' ; the planes M and P at an angle of 94° 12', and the
planes T and P at an angle of 1 11° 57'. The section perpendi-
cular to the planes M and T is an oblique angled parallelogram,
the obtuse angle of which of 117° 28' is divided by the plane
produced by two rows in breadth on the edge G into two angles,
the one of 59 o 30' and the other of 57° 58' ; the first of which
has one of its sides in the plane T, and the other one of its sides
in the plane M. The section perpendicular to the planes M and
P is an oblique angled parallelogram, the obtuse angle of which
equal to 94° 12' is divided by a plane produced by a decrement
by one row on the edge B of the primitive into two angles, the
one of 46° 47', and the other of 47° 25' ; the first of which has
one of its sides in the plane P, and the other one of its sides in
the plane M. The planes I have observed are :

PMT *G-.GH 2 TBCAA AOA*A ,0 4AE 2 (figs.7 8 9).

I ft t n i> y x <j t o u m Tv> > i J

Incidences.

TonM 117° 28'

Ton/ 120 30

M' on I 122 2

M on z 14' 1

Ton; \6

M'on/ 15,

P on y' 98 29

P on x' 128 27

Ponr/ 145 12

Pon* 138 46

Pono' 121 50

P on »' 94 53

P on m 134 46

/on/ J51 28

P on M 85 48*

P on n 133 13*

58 Mr. Rose on Felspar, Albite, Labrador, #c. [Jan.

Pone 137° 22'

PonT 110 57

Ponj/ 125 38

Mono' 115 20

Monu' 122 45

M'onm 116 12

Pone' 91 56

M on v' 141 54

Pona/ 98 37

M'onw' 141 22

Plane Angles of the Primitive Form.

Those of plane P 121° 33' and 58° 27'
M 116 15 63 45

T 106 42 73 18

Anorthite, as well as albite, although not quite so frequently,
presents also hemitrope crystals, I have not given drawings of
them, because they are formed exactly according to the same
laws. This substance can be cleaved parallel to the planes P
and M with equal facility. I have not been able to obtain a
cleavage parallel to the plane T, and I have chosen it for one of
the primitive planes in preference to the plane /, because it is
generally much more brilliant. The fracture in other directions
is conchoidal. The lustre of the cleavages is pearly, and that
of the conchoidal fracture vitreous.

Anorthite is found sometimes crystallized in small masses.
The crystals are perfectly clear and transparent, but very small.

The specific gravity of several fragments weighing 1*463 gr.
bv using water at the temperature of 14° R. has been found
equal to 2-763.

That of small crystals weighing 0*316 gr. mixed with a small
quantity of pyroxene, by using water at 17° R. was found equal
to 2*656.

Concentrated hydrochloric acid entirely decomposes anorthite.
I have found 100 parts of anorthite, the specimens of which, as
well as those of albite, I had obtained through the kindness of
Mr. Weiss, from the collection of minerals in the University of
Berlin, composed of

Silex 44*49 which contains oxygen 22*38 ""111

Alumina 34*46 16*096^ , R Qofi Q

Oxide of iron 0*74 0*23 j ltr,i ~ b > 6

Lime 15*68 4*40 2

Magnesia 5*26 2*04 J 1

Another analysis in which 1 had only 0*6 gr. to examine gave,
however, similar results, and consequently the mineralogical
formula is

MS+2CS+8AS

1824.] M. Levy's Observations on the preceding Paper, 69
when one part of 8 A S is replaced by F S. Anorthite has only
been found hitherto in masses of carbonate of lime at Mount
Somma, near Vesuvius, where it is accompanied only by green
translucent pyroxene. , . v , ,

Observations. — The mineralogical formula indicated above,
appears to be the result of the analyses : I cannot, however,
warrant its exactness, because I could only operate upon very
small quantities ; the first time with 0-628 gr. ; the second time
with 1-482 gr. : it is the result of this last analysis I have given.
The formula would be analogous to other formulae already known,
if there was 9 A S, instead of 8 A S. Then it would be the
same as that of meionite and paranthine, the formula of which is
C S + 3 A S, with this difference, however, that one-third of
C S in anorthite would be replaced by M S. Anorthite would
then be referred to meionite, in the same manner as idocrase is
to garnet, or, according to my brother's analysis, pyroxene to
wollastonite.

I have provisionally given the name of anorthite to this mine-
ral, derived from aoopfos, which signifies without right angles ;
because its crystalline form is principally distinguished from
felspar, in not being at right angles to each other. Haiiy, to
whom the name of felspar did not seem proper, had suggested
for this mineral the name of or those, from two of its cleavages
being at right angles to each other.

Article XII.

Observations on the preceding Paper, with an Account of a new
Mineral. By M. Levy, MA. of the Academy of Pans.

(To the Editor of the Annals of Philosophy.)

SIR Dec. 20, 1823.

Since the notice you inserted in one of the preceding numbers
of the Annals of Philosophy of the division I had made of the
specimens commonly ranked under the name of felspar, into two
distinct species, viz. felspar and cleavelandite, I have seen in the
last number of the Aimales de Chimie a paper by M. Rose, of
Berlin, upon the same subject. An abstract of this paper is
inserted in the present number of the Atmals, and contains, in
addition to the essential part of what I intended to publish, not
only new analyses of both felspar and cleavelandite, and then-
specific gravities, but also the complete determination of two
new species, viz. labrador and anorthite. In consequence oi
this, I shall limit what 1 proposed to send you, to a very few
observations, which M. Rose's paper does not render useless.

60 M. Levy's Observations on the preceding Paper. [Jan.

M. Rose has adopted, as appears from a determination of Weiss,
an oblique rhombic prism for the primitive of felspar. I had
assumed the same form, from the observation of the crystals of
that substance 1 had an opportunity of examining in Mr. Tur-
ner's collection, as well as from the very figures given by Haiiy,
and the measurements given both by him and Mr. W. Phillips.
M. Rose has not stated the reasons which induced Weiss to alter
the determination of Haiiy ; and as I believe they are not
generally known, since Mr. Brooke and Mr. W. Phillips, in their
late publications, have adopted the primitive form of Haiiy, I
shall briefly explain by what considerations I was led to the
same result as Weiss.*

On looking at the figures given by Haiiy in the last edition of
his treatise on mineralogy, as well as on looking at any crystal
of felspar, it will easily be seen that every one of them may be
derived from an oblique rhombic prism, the lateral planes of
which would be, for instance, the plane he has marked I, and
the face opposite and parallel to T, and the base the plane P. If
the primitive were not such an oblique rhombic prism as I have
just described, one would expect to meet with a crystal contain-
ing the face T without the face /, or the modification z without
the modification z', or s without s', or n without «', but the con-
stant simultaneous occurrence of these groups of modifications
perfectly symmetrical relative to the planes P, /, T, both in their
positions and incidences, is certainly decisive. Moreover, in
the form I have adopted, if a cleavage be found parallel to M, it
must be at right angles to the base P, because M is equally
inclined upon / and T, or because it is parallel to a plane through
the oblique diagonals of the bases. This cleavage, as it is well
known, exists in felspar, and is found perpendicular to P. This
angle of 90° would again be a very singular occurrence if the
primitive were a doubly oblique prism, fhe only argument in
favour of Haviy's determination is, his assertion that there is a
cleavage parallel to T, and none parallel to /, as should be
the case, if/, as I have assumed, was one of the lateral primitive
planes symmetrical to T. To this may be answered that even
the cleavage parallel to T is in most cases very difficult to obtain,
that this is not the only example of an oblique rhombic prism,
in which one of the lateral planes is more easily obtained by
cleavage than the other.f It is the case, for instance, in chro-
mate of lead. Moreover, in some of the flesh-coloured speci-
mens, I have succeeded in obtaining a cleavage parallel to /, by
detaching first a thin lamina parallel to P. Finally, Haiiy men-
tions the primitive he has adopted as one of the forms offered
by nature : this form I have never seen ; and I doubt very much
its existence, because it could not be derived from an oblique
rhombic prism froi:;vhich all the others are so obvioirsly deduced.

* See Annals of Vhilosopliy for November.

f See Brooke's Familiar Introduction to Crystallography, p. 189.

1824.] Mr. Levy's Description of a new Mineral. 61

The form M. Rose has taken for the primitive of cleavelandite
differs only in its angles from that T had assumed. He gives for
the incidence of T on M 117° 53'. I have constantly found it
upon brilliant cleavage planes 119° 30', or between 119° 30' and
120°, which makes a difference of 2° between our measure-
ments; mine agrees with that obtained by Mr. Brooke, and I
believe also by Mr. W. Phillips. This difference will of course
change most of the angles calculated by M. Rose, but not so
materially as to make it necessary to trouble you with the result
of my own calculations.

The flat crystals from St. Gothard are, as M.Rose had suspected,
cleavelandite. It was indeed the observation of specimens of
that locality which are not hemitrope, as most crystals of that
substance are, that led me to the distinction of the two substances,
and which gave me the best data for the determination of the
primitive form. Mr. Turner's collection contains a great variety
of forms of that locality ; one of the most complicated I have
represented in tig. 10. In some of the crystals, the planes I

3

have marked d~-' and d? are wanting, and then the crystal has
precisely the same form as some of the varieties of felspar. In
the same collection are found crystals which are not hemitrope,
from the Tyrol and from Siberia. Those from this last locality

are very large, and contain only the modifications p m t and o a
or o 2 , and the figure of the plane m is triangular. However, most
of the crystals are hemitrope, but their form is generally much
more complicated than those M. Rose has figured. He says in
his paper this substance is never found laminar, but from North
America, and from Silesia. I have seen specimens in large
laminae, each of which is formed by the juxta-position of two
laminae parallel to the face T of the primitive, so as to present,
when cleaved parallel to P, the same re-entering angles offered
by the hemitrope crystals of that substance.

I shall feel obliged if you can spare room for a short descrip-
tion of, I believe, a very scarce and new mineral from Vesuvius.
I have observed it upon a specimen Mr. Heuland purchased at
the sale of Mr. Desse, to add to his private collection. This
substance occurs in small brilliant colourless and translucent
crystals. They are sufficiently hard to scratch rock crystal.
Mr. Children, who kindly undertook to examine a small quan-
tity of it, found it to be mostly composed of silex and mag-
nesia. The only form I have observed is represented by fig. 12,
and the crystals cleave easily in the direction of the plane p.
The angles I have measured with the reflecting goniometer led
me to adopt for the primitive form of this substance, a right
rhombic prism, fig. 11, the lateral planes of which corre-
spond to the planes marked m in fig. 12, and the base to the
cleavage. The incidence of the two lateral planes of the primi-

62 Analyses of Books. [Jan.

tive is 128° 54', and the ratio of one side of the base to the
height nearly that of 4 to 7. The other incidences are :

(&', p) = 126° 6'

(&',gO=no 23.

This substance is accompanied by pleonast and olive-green
pyroxene.

I have chosen for it the name otforsterite, in honour of the
late Mr. Forster, who has so much contributed to the advance-
ment of mineralogy by his extensive connections in that branch
of science in every part of the world, and by having laid the
foundation of one of the finest private collections, now in the
possession of Mr. Heuland.

Article XIII.

Analyses of Books.

Philosophical Transactions of the Royal Society of London, for

1823. Part II.

The following are the papers contained in this unusually volu-
minous part of the Philosophical Transactions.

XIII. On a new Phenomenon of Electromagnetism. By Sir
Humphry Davy, Bart. Pres. RS.

We have reprinted this communication in the present number
of the Annals.

XIV. On Fluid Chlorine. By M. Faraday, Chemical Assist-
ant in the Royal Institution. Communicated by Sir H. Davy.

In the next number of the Annals, we intend giving a full
account of the contents of this paper, as well as of another, by
the same chemist, on the Liquefaction of other Gases.

XIV. On the Motions of the Eye, in Illustration of the Uses of
the Muscles and Nerves of the Orbit. By Charles Bell, Esq.
Communicated by Sir H. Davy.

A brief abstract of this valuable paper will be found in the
report of the proceedings of the Royal Society in the Annals
for May, 1823 ; but we extract the section " On the two condi-
tions of the eye, its state of rest, and of activity," on account of
the peculiarly important nature of its contents.

" The eye is subject to two conditions : a state of rest with
entire oblivion of sensation, and a state of watchfulness, during
which both the optic nerve and the nerve of voluntary motion are
in activity. When the eye is at rest, as in sleep, or even when
the eye-lids are shut, the sensation on the retina being then
neglected, the voluntary muscles resign their office, and the

1824.] Philoiophical Transaction for 1823, Part II. 63

involuntary muscles draw the pupil under the upper eye-lid.
This is the condition of the organ during perfect repose.

" On the other hand, there is an inseparable connexion be-
tween the exercise of the sense of vision and the exercise of the
voluntary muscles of the eye. When an object is seen, we
enjoy two senses : there is an impression upon the retina ; but
we receive also the idea of position or relation which it is not the
office of the retina to give. It is by the consciousness of the
degree of effort put upon the voluntary muscles, that we know
the relative position of an object to ourselves. The relation
existing between the office of the retina and of the voluntary
muscles, may be illustrated in this manner.

" Let the eyes be fixed upon an illuminated object until the
retina be fatigued, and in some measure exhausted by the
image, then closing the eyes, the figure of the object will con-
tinue present to them : and it is quite clear that nothing can
change the place of this impression on the retina. But notwith-
standing that the impression on the retina cannot be changed,
the idea thence arising may. For by an exertion of the volun-
tary muscles of the eye-bail, the body seen will appear to change
its place, and it will, to our feeling, assume different positions
according to the muscle which is exercised. If we raise the
pupil, we shall see the body elevated, or if we depress the pupil,
we shall see the body placed below us ; and all this takes place
while the eye-lids are shut, and when no new impression is con-
veyed to the retina. The state of the retina is here associated
with a consciousness of muscular exertion ; and it shows that
vision in its extended sense is a compound operation, the idea
of position of an object having relation to the activity of the
muscles.

" We may also show, by varying this experiment, that an
agitated state of the muscles, or a state of action where the
muscles are at variance or confused, affects the idea of the
image. If we look on the luminous body so as to make this
impression on the retina, and then cover the face so as to exclude
the light, keeping the eye-lids open, and if we now squint, or
distort the eyes, the image which was vividly impressed upon
the retina instantly disappears as if it were wiped out. Does
not this circumstance take place, because the condition of the
muscles thus unnaturally produced, being incongruous with the
exercise of the retina, disturbs its operation?

" If we move the eye by the voluntary muscles, while this
impression continues on the retina, we shall have the notion of
place or relation raised in the mind ; but if the motion of the
eye-ball be produced by any other cause, by the involuntary
muscles, or by pressure from without, we shall have no corre-
sponding change of sensation.

"If we make the impression on the retina in the manner
described, and shut the eyes, the image will not be elevated,

64 Analyses x>f Books. [Jan.

although the pupils be actually raised, as it is their condition to
be when the eyes are shut, because there is here no sense of
voluntary exertion. If we sit at some distance from a lamp
which has a cover of ground glass, and fix the eye on the centre
of it, and then shut the eye and contemplate the phantom in the
eye ; and if, while the image continues to be present of a tine
blue colour, we press the eye aside with the finger, we shall not
move that phantom or image, although the circle of light pro-
duced by the pressure of the finger against the eye-ball moves
with the motion of the finger.

" May not this be accounted for in this manner : the motion
produced in the eye-ball not being performed by the appropriate
'organs, the voluntary muscles, it conveys no sensation of change
to the sensorium, and is not associated with the impression on
the retina, so as to affect the idea excited in the mind ? It is
owing to the same cause that, when looking on the lamp, by
pressing one eye, we can make two images, and we can make the
one move over the other. But, if we have received the impression
on the retina so as to leave the phantom visible when the eye-lids
are shut, we cannot, by pressing one eye, produce any such
effect. We cannot, by any degree of pressure, make that image
appear to move, but the instant that the eye moves by its volun-
tary muscles, the image changes its place ; that is, we produce
the two sensations necessary to raise this idea in the mind ; we
have the sensation on the retina combined with the conscious-
ness or sensation of muscular activity.

" These experiments and this explanation of the effect of the
associated action of the voluntary muscles of the eye-ball, appear
to me to remove an obscurity in which this subject has been left
by the latest writers. In a most scientific account of the eye
and of optics, lately published, it is said on this question, ' we
know nothing more than that the mind residing, as it were, in
every point of the retina, refers the impression made upon it, at
each point, to a direction coinciding with the last portion of the
ray which conveys the impression.' The same author says,
' Kepler justly ascribed erect vision from an inverted image to
an operation of the mind, by which it traces the rays back to the
pupil, and thus refers the lower part of the image to the upper
side of the eye.' What can be here meant by the mind follow-
ing back the ray through the humours of the eye ? It might as
well follow the ray out of the eye, and, like the spider, feel along
the line. A much greater authority says we puzzle ourselves
without necessity. ' We call that the lower end of an object
which is next the ground.' No one can doubt that the obscu-
rity here is because the author has not given himself room to
illustrate the subject by his known ingenuity and profoundness.
But it appears to me, that the utmost ingenuity will be at a loss
to devise an explanation of that power by which the eye becomes
acquainted with the position and relation of objects, if the seuse

1824.] Proceedings 6f Philosophical Societies. 65

of muscular activity be excluded, which accompanies the motion
of the eye-ball.

" Let us consider how minute and delicate the sense of mus-
cular motion is by which we balance the body, and by which
we judge of the position of the limbs, whether during activity
or rest. Let us consider how imperfect the sense of touch
would be, and how little of what is actually known through the
double office of muscles and nerves, would be attained by the
nerve of touch alone, and we shall be prepared to give more
importance to the recti muscles of the eye, in aid of the
sense of vision : to the offices performed by the frame around
the eye-ball in aid of the instrument itself."

A plate accompanies this communication, showing the mus-
cles of the eye as seen in front, and in profile.

(To be continued.)

Article XIV.

Proceedings of Philosophical Societies.

ROYAL SOCIETY. .

The first meeting of this Society for the present session took
place on the 20th of November last, when Major Gen. Sir G.
Murray and John Renuie, Esq. were admitted Fellows ; and the
Croonian Lecture was read,

On the Anatomy of the Human Brain as compared with that
of Fishes, Insects, and Worms; by Sir E. Home, Bart.
V.P.R. S.

This lecture was very short, and consisted, principally, of
remarks illustrative of the microscopical drawings by Mr. Bauer,
with which it was accompanied, some more particular observa-
tions being reserved for the explanation of them. Occasion
was taken to award a high and just tribute to the microscopical
investigations of Swammerdam, which were unequalled, by any,
it was remarked, except those of Mr. Bauer. The ability of
both observers was of such and so rare a nature, that, with
respect to each, it had been ascribed to some particular con-
struction of the microscope ; and it had even been suspected
that Swammerdam had a peculiar method of using the in-
strument, which had died with him.

A portion of very recent human brain, merely steeped in
distilled water, was examined by Mr. Bauer, who perceived in
it rows of globules proceding in straight lines from the cortical
into the medullary part. A comparison was instituted of the
human brain with the same organ in fishes, insects, and worms.
In the tench, the brain has a central cavity, and its basis is
nodulated. In the bee, that organ is larger in proportion than
New Series, vol. vn. f

66 Proceedings of Philosophical Societies. [Jan.

in the other insects which have been examined ; it is also large
in the moth and in the caterpillar.

The reading was commenced, likewise, of Some Observations
on the Migration of Birds; by the late Dr. Edward Jenner,
F. R. S. ; communicated by his Nephew, Mr. H. C. Jenner.

Nov. 27. — Dr. D. Cresswell and Prof. Barlow were admitted
Fellows of the Society ; and the reading of Dr. Jenner's paper
was concluded.

Dr. Jenner had intended to present this paper to the Royal
Society himself, but was prevented from fully completing it, as
to arrangement, by his extensive correspondence on the subject
of vaccination. It commences with some general observations
on the Migration of Birds, and particularly with respect to their
capability of taking such great flights as migration must require,
and which some writers have questioned. Dr. Jenner brings
forward various facts, to show that there are no grounds for
such doubt ; among which are the following : a hobby-hawk
was seen in a vessel near Newfoundland ; and an owi, seemingly
the common brown owl, flying above the Atlantic wave, with as
much agility as if pursuing a mouse in the fields ; cuckoos,
snipes, and other birds, have likewise been seen in the Atlantic ;
a flock of birds resembling linnets settled on the rigging of a ship,
remained awhile chirrupping in concert, and then flew away ;
geese have been caught in Newfoundland with their crops full
of maize, a species of corn which is not grown but at an im-
mense distance from that island. The discussion of this branch
of the subject is succeeded by some remarks on the faculties of
discrimination and guidance which must be exercised by birds,
in the long flights thus taken, and which, Dr. J. conceives, must
be of some peculiar and unknown nature ; pigeons, it is ob-
served, which have been taken several hundred miles, completely
secluded from the light, by being shut up in a box, will, when
set at liberty, immediately return to the place whence they were
taken. The periodical disappearance and return of birds has
been ascribed to hybernation, but of this Dr. Jenner never wit-
nessed an instance ; nor could he ever obtain any satisfactory
evidence of it. When birds appear for the season, they are
never in the emaciated and weakened state attended with, loss
of fat, seen in hybernating quadrupeds when they quit their
retreats ; but, on the contrary, they are quite vigorous, and as
active as at any period. With regard to the supposed immersion
of birds in ponds and rivers for the winter, Dr. J. remarks, that
their respiratory organs are very similar in structure to those of
quadrupeds, and are no better adapted for performing their
functions under water. He took a swift, about the 10th of
August, or on the eve of its departure, and held it under water,
when it died in two minutes. It has been conjectured, that
repeated alternate immersions and emersions might have the
effect of altering the corresponding action of the heart and

1824.] Royal Society. 67

lungs ; but though swifts and martins, it is observed, in reply
to this conjecture, frequently splash in the water over which
they are skimming, yet they never immerge themselves in it, and
indeed if they were to do so, their wings would become so wet
as to prevent their flying. The common duck, when pursued
and forced to dive repeatedly, by a water-dog, arrives at the
surface again much exhausted ; as is likewise the case with
grebes and auks, after repeated diving. Dr. Jenner had been
in the habit of receiving Newfoundland dogs from that country,
and had ascertained that they never continued under water for
more than thirty seconds, and even then seemed confused when
they came up. It had been asserted that negro and other
divers remained under water several minutes ; but Dr. J. con-
ceives this assertion to be grounded only on a vague guess,
and that the time was not measured by a stop-watch.

The next division of the paper relates to the remarkable
effect of instinct in birds, of their returning to build on the
same spot for many successive seasons. The author took twelve
swifts from their nests in a barn, indelibly marked them all, by
taking off two claws from one foot of each, and then set them
at liberty. Some of them were caught again on the same spot,
at the expiration of a year, and others after two years had
elapsed ; they were not attended to afterwards, but at the expi-
ration of seven years from their original capture, one of these
marked swifts was brought in by a cat.

Dr. Jenner next proceeds to state, as the cause of the migration
of birds, that the tumid and enlarged state of the testes in the
male, and of the ovariain the female, at the season of their depar-
ture, prompt the animals to seek those countries where they can
obtain proper succours for their offspring; — that, in fact, the
nestlings are the objects of this provision. The parent birds
leave the countries they migrate from at a time when their own
wants are completely supplied ; and they remain in those to which
they migrate, no longer than suffices for the rearing - of theiryoung.
Thus the swifts arrive in this country about the 5th or o'th of
April, and depart hence about the 10th of August. — Dr. Jenner
here observes, as a remarkable circumstance, that Ray, who
attributed the migration of fishes to its true cause, that of
seeking proper situations for spawning, overlooked the cor-
responding impulse as actuating birds. — The martins leave
this country successively, some continuing to rear a brood
,h li ter than others : many of these birds roost in the walls
of Berkeley Castle ; and Dr. Jenner found, by dissecting a num-
taken at the same time, that the ovaria of the females were
iu a variety oi slates ; in some the eggs being no bigger than
hemp seed, while in others they were as large as peas ; the
testes of the males exhibited analogous degrees of tumidity.

Swallows are seen flying over pools and waters iu spring,
in search of the gnats on which they are then obliged to

f2

68 Proceedings of Philosophical Societies. [Jan.

feed ; and not because they have arisen from the waters. Their
usual food, like that of swifts and martins, is a species of sca-
rabseus, as the author ascertained by dissection.

Birds that rear several broods in the season, frequently leave
the last brood to perish; thus a pair of swifts that had brought
up three broods in one nest left the fourth to perish ; and the
mother came back in the following year, threw outthe skeletons,
and laid in the nest again. Many nests of late birds, of various
species, are deserted in this manner by the parent animals ; but
the latter thus leave the country when it abounds with their own
food.

The young birds, it is remarked, cannot be directed in their
migratory flights by the parents, but must be guided by some
unknown principle : if it be admitted in the case of swifts,
martins, and other birds associating together in flocks, that the
young may be directed by the motions of their fellows, yet this
cannot be the case with the nightingales ; nor with the cuckoos,
who, though reared in the nests of many different birds, are re-
gular migrators. The parent cuckoo has left the country before
its young are reared, always departing early in July.

Dr. Jenner next gives some particulars relative to the enlarge-
ment of the testes and ovaria in birds, supplementary to those
which have been pointed out by Mr. John Hunter. In those birds
who pair but for a short time the testes are small, while in those
with whom the connubial compact is of long continuance, they
are large. In the cuckoo, a polygamist, and who continues
with the female but for a very short time, the testes are of the
size of a vetch only ; but in the wren, whose attachment to his
mate extends from spring to autumn, they are equal to a pea in
magnitude ; thus much larger in the latter than in the former, in
proportion to the size of the bird. A continued supply of gene-
rative power is required in birds who pair for a long time, in
case the brood should be destroyed — but in those like the cuckoo
this provision is unnecessary.

The whiter birds of passage leave this country for precisely
the same reason that impels the spring migrators to come hither;
some of them, as the wild-duck and the wood-pigeon, which
occasionally build here, are irregular in their migration; the
most regular are the red-wing and the field-fare, of whose
building in this country Dr. Jenner never met with an instance.
The food of the former, he observes, is not haws, or the fruit of
the white thorn, as has been stated, but worms and insects,
which they gather from the ground, feeding in flocks ; Dr. J.
had seen them dying of famine when haws were abundant. A
gentleman saw a flock of field-fares on the day before the thaw-
ing of the great frost of 1794, and they seemed as wild and vi-
gorous as if in season ; he shot one, which Dr. Jenner examined,
and found to be in excellent condition, but there was no food in
the stomach, and the last which the animal had eaten was di-

1824.] Royal Society. 69

gested : now as the ground was covered with snow, and as the
long frost had destroyed everything they could feed on, these
field-fares must have returned here for a short time, in conse-
quence of the inclemency of the weather abroad. Red-wings
and field-fares always leave this country when they are in the
best condition. The approach of severe frost is indicated by
the arrival of water-birds, as that of thaw is by the coming of
the spring migrators. Birds often outstrip in their migrations
the progress of the frost itself.

Dr. Jenner considers that Dr. Darwin must be mistaken in
what he says respecting cuckoos seen feeding their young. The
birds in question must have been goat-suckers, which are very
easily confounded with cuckoos by those who are not fully con-
versant with the characters of their plumage, Sec.

This very interesting paper concludes with a recapitulation of
the principal facts contained in it, and of the author's views
respecting them.

Dec. 1. — The anniversary meeting took place this day (St.
Andrew's Day falling on a Sunday), and was numerously attended.

After stating the names of those Fellows whom the Society
has had the misfortune to lose since the last anniversary, the
President, Sir H. Davy, delivered a discourse, in which he no-
ticed such of them as had by their communications to the
Society, or by their philosophical labours, advanced the progress
of science. In presenting the following sketch of the Presi-
dent's address, we wish it to be distinctly understood that we
pretend to offer a mere outline ; it is quite impossible, in the
space to which we are necessarily confined, to impart to the
reader an idea of the high and eloquent eulogium which the
President bestowed upon the memory and labours of some of the
deceased Fellows. — Beginning withDr.Hutton,he observed, that
his labours of more than half a century had established his re-
putation as one of the most able mathematicians of his country
and age ; after alluding to the papers which had been published
in the Transactions of the Society, he observed, that during the
long period that he was Professor at Woolwich, he might be
regarded as having eminently contributed to awaken and keep
alive that spirit of improvement among the military students,
which has so much contributed to the character of the British
officer, and which has been attended with such beneficial results
to the country. The merits of Dr. Hutton as an experimental
philosopher, the President observed, were of no mean kind ;
they were displayed in his paper on Gunnery, for which he re-
ceived the Copleyan medal, in 1778 : this paper contained an
account of some difficult and delicate experiments on the force
of gunpowder, from which conclusions were drawn connected
with important practical results. Sir Humphry then observed,
that Dr. Hutton's greatest work was, perhaps, his calculation of
the Density of the Earth, founded upou Dr. Maskelyne's expe-

70 Proceedings of Philosophical Societies. [Jan.

riments on the effects of Schehallien on the Plumb-line. This
labour, comprehending the most complicated arithmetical pro-
cesses, the President observed, would for ever associate his name
with one of the grandest and most important physical problems
solved in the last century, and transmit it with honour to
posterity.

To speak of Dr. Edward .Tenner as a man of science of our
own particular school, the President observed, would be saying
little, for he had a higher claim to our deep regret and profound
admiration as a benefactor to mankind in general. — After ad-
verting to the invention and effects of vaccination, Sir Hum-
phry Davy remarked, that the originality of Dr. Jenner's mind
and the accuracy of his observation are shown in his first
communication to the Society, on the Natural History of the
Cuckoo; and in the pursuit of his great object, he met with
obstacles which required no ordinary degree of perseverance,
and of confidence in his own powers to overcome ; the fairway
of judging of the merits of an inventor, said Sir Humphry, is
by the operation of his discovery on civilized and social life ; —
and in this respect Dr. Jenner stands almost alone.

Of Dr. Baillie, the President observed, that whether consi-
dered as a physician or as a man, his talents and his virtues
were alike distinguished, — his works show the accuracy and
coolness of his judgment; his minuteness in observation ; and
his acuteness in referring effects to their true causes, amidst
the complicated phenomena offered by diseased organs. No
man was ever more free from any taint of vanity or affectation ;
he encouraged and admired every kind of talent, and rejoiced
in the success of his contemporaries ; and he maintained, even
at court, the simplicity and dignity of his character.

Col. Win. Lambton, the President observed, was a veteran in
the army of India : two papers of his are published in the Trans-
actions of the Society, on the Admeasurement of an Arc of the
Meridian in Hindostan — a work of great labour, displaying
minute accuracy and extraordinary perseverance, and carried on in
a climate unfavourable to bodily exertion or intellectual pursuit.
This arc extends in amplitude very nearly ten degrees ; and
Col. Lambton had the honour of having laid down the largest
Single arc ever measured upon the surface of the globe.

The President, whennoticing Archdeacon Wollaston, observed
that the little which ho had contributed to the Society's Trans-
actions occasioned regret that he had not been a more frequent
contributor. — His papers, said Sir Humphry, on the Measure-
ment of Heights, and on the Alteration of the Boiling Tempe-
rature, offer a valuable resource in ascertaining the altitudes of
mountains, and are remarkable for accuracy of method and
distinctness of detail.

After making respectful mention of Dr. Cartwright and Mr.
Jordan, the President proceeded to make some observations on

1824.] Royal Society. 71

the award of the Copleyan medal, to John Pond, Esq. Astronomer
Royal, for his various observations and communications pub-
lished by the Royal Society ; we can give a still fainter idea of
this discourse, than of the tributes of praise to the deceased
members : it was received by the Society in a manner which
evinced their strong desire that it should be made a permanent
record by the press.

Having given au historical sketch of the labours of the
Astronomer Royal, and stated his merits as an accurate and
indefatigable observer; the President observed, that it is very
difficult to point out the specific merits of astronomical obser-
vations : they are not, he said, like philosophical or chemical
experiments, which produce an immediate result ; their delicacy
and exactness, he observed, could only be judged of by those
who have witnessed the manner in which they are made, and
who are accustomed to the same kind of labour ; and as they
often relate to long periods of time, their correctness and value
perhaps can only be fairly estimated by posterity.

The President then took a rapid but luminous historical view
of the labours of Flamstead, Bradley, and Maskelyne, and he
alluded to the discussion still pending between the Astronomer
Royal and Dr. Brinkley on the subject of parallax.

Sir Humphry then adverted to the principal points of discussion
in the papers of the Astronomer Royal, viz. the grand and long
agitated question of the parallax of the fixed stars, and an
apparent declination or change of position in a number of the
stars, not to be accounted for by any known laws. He said the
Council did not mean by this token of their respect for Mr.
Pond, to give any opinion on the subject of parallax, which,
however, it was satisfactory to find, was now brought into veiy
narrow limits ; nor did they enter at all into the subject of the
apparent declination, for on a matter of such great importance,
new observations, and the researches of years, were required to
fix the judgment of scientific men.

Having mentioned the advantages which navigation has ac-
quired from astronomical observations, and which to this coun-
try were peculiarly necessary, on account of its maritime and
colonial empire, the President observed, that astronomy had
exerted a powerful effect in the general improvement of the
human mind, by developing the true system of the universe. In
consequence of the discoveries made in it, all the superstitious
notions — all the prejudices respecting the heavenly bodies,
which had such an effect upon the destinies of individuals and
of kingdoms in ancient times, have disappeared : and the science
as it now exists is the noblest monument ever raised by man to
the glory of his Maker; for its ultimate and refined deyelope-
paents demonstrate combinations which could only be the result
of infinite wisdom, intelligence, and power.

72 Scientific Intelligence* [Jan.

On presenting the medal to the Astronomer Royal, the Presi-
dent addressed him nearly as follows : — I now present you this
medal. — Consider it as a token of the respect of the Society, and
of the confidence of the Council in the great accuracy of your
observations: receive it likewise as a memorial that future
important labours in the same department of science are hoped
for, nay, are expected from you. I am well aware that some
of the greatest and most important objects of discovery, and
those, perhaps, most obvious, have been attained by the labours
of your predecessors. Yet Nature is inexhaustible; and the
powers and resources of the human mind, and the refinements
of art, have not as yet attained their limits. Who would have
anticipated, half a century ago, the discoveries of Herschel and
Piazzi ?

Though pursuing a science that may be considered as in
its maturity, you have advantages of a peculiar kind ; more per-
fect instruments than were ever yet employed ; more extensive
assistance than any of your predecessors ; and upon these points
the liberality and promptitude with which Government have
entered into all the views of the Council of the Royal Society for
the improvement of the Royal Observatory, cannot be too much
admired. Continue to pursue your honourable career, and
endeavour to be worthy of having your name transmitted to
future generations with those of your illustrious predecessors.
Of all the branches of science, astronomy is that from which this
Society has gained most glory, and it never has lost, and I feel
convinced never will lose, any opportunity of advancing its pro-
gress, and honouring its successful and zealous cultivators.

Article XV.

SCIENTIFIC INTELLIGENCE, AND NOTICES OF SUBJECTS
CONNECTED WITH SCIENCE.

I. Supposed Origin of the Art of Smelting Iron.

The following remarks explanatory of a passage in the Rev. J.
Hodgson's " General Conclusions of an Inquiry into the Era when
Brass was used for Purposes to which Iron is now applied" inserted in
the last number of the Annals, at p. 407, were precluded from appear-
ing in their proper place as a note to the paper, by circumstances
attending their passage through the press.

It would appear, from a paragraph in the former part of his paper
(Arch. M\. vol. i. p. 40), that Mr. Hodgson conjectures the idea of
producing metallic iron by the artificial application of fire to its ores,
to have been suggested to mankind by the observation, that the stones
containing malleable iron, or meteorites, descended upon the earth in

1824.] Scietitijic hitelligence. 73

an ignited state, or from fiery bodies in the atmosphere ; though the
application of the terms aerolite and meteoric stone to meteoric iron and
stones indiscriminately, render his remarks somewhat ambiguous.
There really exists, however, an indeterminate kind of transition, from
the masses of meteoric iron entirely free from earthy or stony matter,
to the meteoric stones in which that metal is merely disseminated in
grains. Thus, placing the Brazilian or Cape iron, and the Benares or
L'Aigle stones at the extremities of the scale, the intermediate degrees
will be formed by the Siberian iron, with its globules of (so called)
meteoric olivine, the Elbogen iron in which globules of a similar sub-
stance are imbedded, and the stones which fell near Tabor, in Bohemia,
in 1753, containing nearly one-fourth of their weight of iron. A suf-
ficient quantity of the metal to impart a knowledge of its usefulness
might have been separated from such stones as the latter, without
much difficulty; and thus (allowing the validity of Mr. Hodgson's con-
jecture), mankind might have been led to the smelting of iron from its
ores. It seems, indeed, that the Esquimaux inhabiting the western
coast of Greenland, visited by Capt. Ross, actually edge their bone
knives with small pieces of iron extracted from a meteoric stone, and
flattened for the purpose. Mr. Hodgson is not the only writer who
has attributed the first knowledge of metallic iron to the observation
of native meteoric masses of that metal, for this idea has also been
expressed by Mr. D. Mushet, in his article on Iron-making, in the
Supplement to the Encyclopaedia Britannica. The circumstance is
somewhat remarkable, that the same extraordinary masses of iron,
which, when first discovered, and even for a considerable subsequent
period, were supposed by various writers to have resulted from ancient
smelting operations, should now be considerec" as having pointed out
to mankind the means of obtaining that metal by smelting.

Mr. Hodgson appears to have been misinformed with regard to the
balls of iron-stone found in Sicily, which he alludes to: they certainly
have no similarity in substance "to the true aerolites;" aerolites
have no peculiar shape, but are extremely various and irregular in that
respect ; and the balls of iron-stone have no doubt received the appel-
lation of thunderbolts for the same reasons, indirectly derived from a
knowledge of meteorites, which induced different nations of antiquity
to confer it on various other minerals, and even on certain organic
remains. E. W. B.

II. Composition of Ancient Bronze.

The following particulars respecting ancient bronze are derived from
two papers by the late Dr. E. D. Clarke, read before the Society of An-
tiquaries a few years since, and published in their Archaeologia ; but
not hitherto transferred to any more general medium of scientific
information.

In Dr. Clarke's ** Observations upon some Celtic Remains discovered
near Saxvslon, seven miles from Cambridge" Arch. vol. xviii. p. 340 —
343, he describes certain antiquities which had been found on the
3d of August, 1816, accompanying a human skeleton, about three feet
below the surface of the ground, on the top of a small eminence called
Huckeridge Hill. They consisted of two vessels of bronze, some
fragments of the coarsest black terracotta, an iron sword entirely con-
verted into oxide, a massy bronze ring which had been the foot of the
larger vessel, the iron umbo of a shield, a bronze broach or buckle,

74 Scientific Intelligence. [Jan.

and a small iron fibula. There was nothing Roman in their character;
the form of the sword, in the Rev. Mr. Kerrich's opinion, was not
Roman ; the fragments of terra cotta resembled those found with Celtic
remains ; and these circumstances, notwithstanding their being disco-
vered near the Roman station upon the Gog Magog Hills, tended
to show that they were not of Roman origin. The vessels' consisting
of an alloy of copper and tin seemed likewise, in Dr. Clarke's opinion,
to refer these remains to an earlier period than the time of the Romans
in Britain.

Dr. Clarke found that the bronze of which the vessels were made,
was composed of 88 parts of copper, and 12 of tin : he ascertained,
also, that the bronze coins of Antoninus Pius and of Marcus Aurelius
consisted of the same alloy.

In his " Account of 'some Antiquities found at Fulbourn in Cambridge-
shire," Arch xix. 56 — 61, Dr. C. describes two swords, a spear-head,
and two ferrules supposed to have been the feet of spears, which were
found on Fulbourn Common early in ] SIT. They were all of bronze,
the spear and swords formed on the Grecian model; a bronze sword
resembling the latter had been taken out of the river Cam many years
before, and swords of the same kind had been found in Ireland. The
alloy was hard and brittle ; its fracture, earthy, white, and destitute of
metallic lustre, but upon filing showed the splendour and colour of
gold; its specific gravity was 9-200; it consisted, like the bronze of
the other relics, of 88 copper and 12 tin.

Dr. Clarke adverts, in the conclusion of this paper, to the "uniform-
ity characterising all the results which different chemists have obtained
in the analysis of ancient bronze ; a degree of uniformity," he conti-
nues, " hardly to be explained without supposing that there may have
existed a "native compound of the two metals thus united. In almost
every instance the proportion of the copper to the tin has been 88 to 12.
This was the result of the analysis made by Mr. Hatchctt, of the bronze
nails brought by Sir Win. Gell from the tomb of Agamemnon at
Mycence ; the same result was also obtained in the analysis by Dr.
Wollaston, of some arrow-heads of bronze found in the South of Russia;
and I have found the same constituents similarly combined in various
specimens of bronze from Grecian and from Celtic sepulchres ; in the
bronze lamps of ancient Egypt, and in the lares, weapons, and other
bronzes of the same country. That in the analysis of bronze, found in
countries widely separated, there should not be a more perceptible
difference in the proportion of their chemical constituents, is a remark-
able circumstance. The Gaulish axe found in France, by M. Dupont
de Nemours, and which cut wood like a steel axe, might be considered
as an exception ; because it contained, according to the analysis of
Vauquelin, 87 parts of copper combined with 9 parts of tin ; but in
this axe there were also present 3 parts of iron; perhaps an impurity
of the tin ; which is rarely free from an admixture of other metals.
The tin of the Fulbourn swords, when exposed to a violent heat,
yielded an alliaceous smell denoting the presence of arsenic ; and a
very small portion of a black insoluble powder remained in the nitric
acid after the solution of the copper.

" To conclude, therefore, if we may be permitted to consider these
bronze reliques as so many characteristical vestiges of a peculiar peo-
ple, to whom the art was known of giving a maximum of density to

1824.] Scientific Intelligence. 75

copper and tin, by a chemical operation, we shall be at a loss, either to
ascertain their origin, or to account for their wide dispersion. Such
reliques, as it has been proved, are found alike in Egypt and in Greece,
in Great Britain, and in Ireland. To this it may be added, that the
most ancient bronze coins of India (of which I have lately analyzed
some that were found near the Byzantium of Larice, upon the Baryga-
zenus Sinus), consist of a similar alloy ; and I have reason to suspect
that the bronze idols of Tahtary, and of China, will, upon a chemical
examination, be found to contain the same ingredients."

III. Parhelia, 8$c.

The following is an account of parhelia and other phenomena
observed at Darlington, in the county of Durham, oa the 30th of Oct.
1823.

The writer saw it first at ten minutes past twelve.

In a line with the sun, and equidistant from it, were two bright
spots coloured like the rainbow, from one of which came a stream of
light in a horizontal direction. These spots appeared to be the ter-
mination of a bright semicircle, having the sun for its centre, and
arching upwards. The most surprising part of the sight was another
arc diverging contrarywise, having the same or a larger radius, and
joining the other at the back, or outer side. The most beautiful part
of the sight was another double arc, just like the one I have described,
in or near the zenith ; very bright, and having all the colours of the
rainbow. The phenomenon, varying only in the degree of brightness,
continued for three-quarters of an hour, and one of the spots remained
ten minutes longer.

The sky was nearly or quite cloudless, and very misty ; the wind
due north. Light clouds soon made their appearance after the arcs
disappeared.

A letter from the same observer, dated Nov. 17, 1823, gives further
particulars, viz.

The two parhelia appeared on the external margin of the prismatic
semicircle, at the two extremities of its horizontal diameter. The
brighter one lasted the longest. The colours were not very well
defined; yellow predominated. The arcs nearest the sun had the
least of colour in them, being scarcely more than bright or luminous
appearances ; the more distant ones had a good deal of colour.

I also observed, which I think I did not before mention, about 90°
from the sun, and about its altitude, a large faintly bright spot, and a
light streak from it in a horizontal direction, both quite colourless :
this was visible nearly as long as the rest of the phenomenon.

It would be interesting to know over what extent of country the
phenomenon presented the same appearance. In some parts it might,
perhaps, appear more perfect.

IV. Fffect of Heat in lessening the Cohesive Force of Iron.

A bar of malleable iron, three feet in length, and one inch square,
was heated to 212°, and the machine for measuring its flexure being in
readiness, so that a weight of ;>00 lbs. could be instantly let down upon
the bar; while at the same time the observer adjusted the index to
zero. These operations having been effected in a close and warm

76 Scientific Intelligence. [Jan.

room, with as little loss of heat as possible, the windows were thrown
open, the heating bath removed, and the effect of cooling observed.

The flexure decreased as the bar cooled, and after it had remained
two hours in order to be cooled down to the temperature of the room,
which was 60°, the flexure had decreased three-fourths of one of the
divisions of the scale ; and when the weight was raised from the bar, it
returned through 14 divisions. Hence we may conclude that by an
elevation of temperature equal to 212° — 60° = 152 degrees, iron
loses about a twentieth part of its cohesive force, or will bend one-
twentieth more by the same load. This is equal to about a 3000th
part for each degree.— (Tredgold on Cast Iron, 2d Edit. p. 104.)

V. Correctness of Greenwich Observations.
(To the Editor of the Annals of Philosophy.)
DEAR SIR, Blackman»rircct, Dec. 20, 1824.

In the October number of the Annals, a notice was inserted by me,
wherein it was stated, " a communication has, we understand, been
received from Mr. Bessel, acknowledging that his catalogue of princi-
pal stars requires a correction for instrumental flexure, thereby admit-
ting the superiority of the Greenwich one." It seems, however, that
the accuracy of the report is by Messrs. Tilloch and Taylor contra-
dicted ; * upon what grounds, it is immaterial to inquire : but as a
charge of misrepresentation is insinuated, I shall merely state, that a
letter was sent by Dr. Tiarks (a German astronomer in the pay of the
British Government), containing an extract of a letter (translated into
English) which he had received from Mr. Bessel, couched in such a
manner as to induce the gentleman to whom it was addressed, to trans-
mit to Mr. Troughton a note, informing him of Mr. Bessel's
concession ; and which note was shown to me, as well as to many
others, interested in these matters. Not, however, content with
having done thus much, Dr. Tiarks subsequently called upon Mr.
Troughton, and with much apparent satisfaction, personally communi-
cated to him the same concession on the part of his friend ; and among
other things said, " Bessel had acknowledged that had he used Pond's
mode of observing sooner, he should have gotten his latitude cor-
rectli/." And at this time there can be no doubt but that Dr. Tiarks
considered himself justified in promulgating Mr. Bessel's acknowledg-
ment of the superior accuracy of the Greenwich catalogue. What new
light may have since broken in upon this gentleman, 1 do not pretend
to know ; it is right, however, the readers of the Annals should be
apprised, that the communication was not made to them upon slight
grounds. Mr. Bessel also should be informed, that whatever " idle
reports " (if such they at present be) have gone abroad, are of German,
not of British origin ; and that they have been circulated by the indus-
try of his own friend, and from a letter of his own writing.

James Soeth.

VI. British Museum and Edinburgh Revieiv.
The author of an article in the Edinburgh Review, on the British

♦ Philosophical Magaxine for November la«t.

1824.] New Scientific Books. 77

Museum, would feel much obliged to the Editor of the Annals of Phi-
losophy, if he would permit him, through the medium of the Annals,
to correct a few errors which have crept into the above article, and
which might be considered as instances of bad faith or ignorance were
they not acknowledged to proceed from the hurry of the moment, and
the want of an opportunity of correcting the proof sheet.

Page 382.— The price of the Elgin marbles is stated at 8000/. ; but
it should have been 6000/.

Page 885. — Murex Carinatus is misprinted M.carincelus.
Page 389.— The paragraph beginning " The purchases made two or
three years ago by Dr. Leach," should have run thus: — " The pur-
chases made several years ago for the Museum included some extremely
rare and splendid trochili, or humming birds, some of which would
bring three or four guineas a piece."

Page 390, line 18. — " This immense herbarum," should have been,
M His immense, &c."

Page 390. — The trustees are said to be 41 ; but they are now 43.
Page 391.— They should have been stated at 21 official trustees^
including the three principal Secretaries of State; 7 family trustees, of
which 1 represents the family of Sloane, 2 that of Cotton, 2 that of
Harley, 1 that of Townley, and 1 Lord Elgin. The elected trustees
are 15, making in all 43.

There are a few minor errors of trifling importance, because they
do not affect the accuracy of the statements : but the author has the
satisfaction of knowing that his strictures have produced a sensation in
the quarter where he most desired it ; and the next opening of the
Museum will convince the public that his animadversions have pro-
duced beneficial effects. He has been the cause of the destruction of
numberless moths ; and some of the insect treasures of the Museum
have been recently brought to light. He had but one object — to call
public attention to a great abuse ; and if his zeal for the cultivation of
a favourite study has betrayed him into warmth of expression, he hopes
that he has indulged in no unbecoming personalities.

An Old Cokrespondent.

Article XVI.
NEW SCIENTIFIC BOOKS.

PREPARING TOR PUBLICATION.

M. de la Beche will shortly publish a Selection of the Geological
Memoirs contained in the Annales des Mines, together with a Synop-
tical Table of Equivalent Formations, and M. Brongniart's Table of
the Classification of Mixed Rocks : in 1 vol.8vo.

Mr. C. Chatfield has in the press a Compendious View of the History
of the Darker Ages, with Genealogical Tables ; to form 1 vol. 8vo.

A Guide to the Mount's Bay and the Land's End, comprehending
the Topograohy, Botany, Agriculture, Fisheries, Antiquities, Mining,
Mineralogy, and Geology, of Western Cornwall : Second Edition.
Illustrated by Engravings on Copper and Wood. By a Phybictuu.
To form 1 pocket volume.

78 New Patents. [Jan.

Article XVII.

NEW PATENTS.

Sir W. Congreve, of Cecil-street, bart. Strand, for various improve-
ments in fire-works. — Oct. 16.

A. Buchanan, of Cathrine Cotton Works, Glasgow, merchant, for
his improvement in the construction of weaving looms impelled by
machinery. — Oct. 16.

J. Ranking, Esq. New Bond-street, Westminster, for his newly
invented means of securing valuable property in mail and other stage
coages, travelling carriages, waggons, caravans, and other similar
public and private vehicles, from robbery. — Nov. 1.

G. Hawkes, Lucas-place, Commercial-road, Stepney Old Town,
Middlesex, ship-builder, for his improvement in the construction of
ship anchors. — Nov. 1.

G. Hawkes, Lucas-place, Commercial-road, Stepney Old Town,
Middlesex, ship-builder, for certain improvements on capstans. —
Nov. 1.

W. Burdy, Fulham, mathematical-instrument maker, for his anti-
evaporating cooler to facilitate and regulate the refrigerating of worts,
or wash, in all seasons of the year, from any degree of heat between
boiling and the temperature required for fermenting. — Nov. 1.

T F. Gimson, Tiverton, Devonshire, Gent, for various improvements
in addition to machinery now in use for doubling and twisting cotton,
silk, and other fibrous substances. — Nov. 6.

T. Gowan, Fleet-street", London, truss-manufacturer, for certain
improvements on trusses. — Nov. 11.

J. Day, Esq. of Barnstaple, Devonshire, for certain improvements in
percussion gun-locks applicable to various descriptions of fire-arms. —
Nov. 18.

J. Ward, Grove-road, Mile-End-road, Middlesex, iron-founder, for
certain improvements in the construction of locks and other fastenings.
—Nov. 13.

S. Servill, of Brower's Hill, Bisley, Gloucestershire, clothier, for his
new mode or improvement for dressing of woollen or other cloths. —
Nov. 18.

R. Green, Lisle-street, St. Anne, Middlesex, sadlers' ironmonger,
for certain improvements in constructing gambadoes or mud-boots,
and attaching spurs thereto, and part of which said improvements are
also applicable to other boots. — Nov. 13.

It. Stein, Tower Brewery, Tower-hill, brewer, for his . : .n-

struction of a blast-furnace, and certain apparai
therewith, which is adapted to burn or consume fuelin .. more ecoud-
mi cal and useful manner than has been hitherto practised. — Nov. 13.

J. Gillman, Newgate-street, silk warehouseman, and J. H. Wilson,
Manchester, silk and cotton manufacturer, for certain improvements
in the manufacture of hats and bonnets. — Nov. 18.

J. Heathcoat, Tiverton, Devonshire, lace-manufacturer, for a ma-
chine for the manufacture of a platted substance composed either of
silk, cotton, or other thread or yarn. — Nov. 20.

1824.] Mr. Howard's Meteorological Journal.

79

Article XVIII.

METEOROLOGICAL TABLE.

Barometer.

Thermometer.

Daniell's hyg.
at noon.

1823.

Wind.

Max.

Min.

Max.

Min.

Evap.

Rain.

llthMon.

Nov. 1

NT W

3022

2986

45

27

_

2

N W

30-23

30-16

46

25

—

3

N W

30-16

29-S3

45

32

—

4

s w

29-83

29-74

49

44

—

21

5

E

30-03

2974

50

44

—

IS

6

E

30-05

30-03

5S

48

—

44

7

N W

30-27

30-05

55

50

—

27

8

N W

30-50

30-27

56

38

—

9

N E

30-61

30-50

46

32

— .

10

E

30-68

30-61

46

29

—

11

E

30-68

30-57

42

23

—

12

E

30-57

30-54

40

21

—

13

S

30-54

30-44

43

23

—

M

s w

30-44

3035

44

32

—

15

N w

30-49

30-36

50

'36

—

16

N

30-50

30-49

51

33

'51

,

17

N w

30-52

30-50

42

37

—

—

18

N E

3051

30-33

48

42

—

19

E

3033

30-18

40

40

— i

20

S W

30-28

30-17

51

40

—

21

w

30-28

50-12

48

45

—

22

s w

30-12

30*07

47

39

—

23

s w

30-17

30-12

48

43

—

24

s w

30-31

30-12

50

45

—

2.5

S V\'

30-34

30-31

50

41

—

26

N W

30-33

30-30

48

44

■ —

27

s w

30-30

30-15

48

45

—

28

s w

30-15

29' 85

49

45

—

35

29

s

29S5

29-60

52

44

—

13

30

s w

29 79
30-68

29*59

2959

57

50

•35

13

58

21 !

0-86

1-72!

The observations in each line of the table apply to a period of twenty-four hours,
beginning at 9 A. M. on the day indicated in the first column. A dash denotes that
the result is included in the next following observation.

80 Mr. Howard's Meteorological Journal. [Jan. 1824.

REMARKS.

Eleventh Month,— 1. Cloudy. 2. Fine: white frost in the morning. 3. White
frost: foggy. 4. Cloudy. 5. Rainy. 6. Fine. 7. Rainy. 8. Cloudy. 9. Fine.
10. Very fine. 11. Fine. 12. Fine: hoar frost. 13. Ditto. 14. Hoar frost:
foggy: overcast. 15. Overcast. 16. Very fine. 17. Overcast: a little rain in the
morning. 18, 19. Overcast. 20. Fine. 21— 24. Overcast. 25. Foggy rntraing :
overcast. 26,27. Overcast. 28. Cloudy. 29. Rainy. 30. Cloudy.

RESULTS.

Winds : NE, 2 ; E, 6 ; S, 1 ; SW, 12 ; W, 1 ; NW, 8.

Barometer : Mean height

For die month 30-233 inches.

For the lunar period, ending the 25th 30-183

For 15 days, ending the I3th (moon south) 30*145

For 12 days, ending the 25th (moon north) . ........ 30-308

Thermometer: Mean height

For the month 43-115°

For the lunar period 42-550

For 30 days, die sun in Scorpio 42*483

Evaporation . 0-86 in.

Rain 1-72

Laboratory, Stratford, Twelfth Month, 22, 1823. R. HOWARD.

';,,„■ 81

y.s.vi.xm

Fig. z.

Fig. ■>.

Tig. 3.

Tig. I.

Tig. 5.

Fiii. 6.

Fig. 7.

Fig. 8.

Fig. 9.

Tig. 10.

Engraved fbrduJnnals of Philosophy fbrBaldwin. Cradoak fcJoy. Fei.2 /*-'/.

ANNALS

OF

PHILOSOPHY.

FEBRUARY, 1824.

Article I.

Experiments on the Stability of Floating Bodies.
By Col. Beaufoy, FRS. (With a Plate.)

(To the Editor of the Annals of Philosophy .)

DEAR SIR, Bushey Heath, Jan. 1, 1824.

In the year 1798 a disquisition on the stability of ships by
that celebrated and eminent mathematician the late Mr. Atwood,
was read before the Royal Society, and published in the Trans-
actions. As this work is allowed to be superior to any other on
the same subject in the English language, it may not be unac-
ceptable to those concerned in the planning or building of ves-
sels, to have this gentleman's theoretical deductions submitted
to the test of experiment ; for however satisfactory mathematical
reasoning may be to the scientific, the generality of readers are
more fully convinced by experimental proof.

I remain, dear Sir, yours very truly,

Mark Beaufoy

The apparatus with which these experiments were made is
similar to the one described and illustrated by a plate in the
Annals of Philosophy for March, 1816, and to which I request
your readers will refer. Improvements, however, were made on
the present occasion, by fixing two pieces of wood in a diagonal
direction, one on each side of the mast, to prevent its bending
by the inclining weight : and for greater security, their lower
extremities were firmly tied to the transverse piece that con-
ceit; Series, vol. vii. g

82 Col Beaufoy on the [Feb.

nected the sides of the model, and through which the mast was
inserted. A second alteration consisted in a more accurate
adjustment of the centre of gravity at any given point of the
figure when loaded. Raising the ballast (bars of lead) at first
nearly produced this effect, which was afterwards determined
with greater nicety by pouring shot into a cup fixed upon the
top of the mast. This contrivance so well answered the intended
purpose, that the results of several trials were found not to vary
from each other more than five-hundreths of an inch.

Different formed bodies were used, measuring in breadth ten
inches, and in length fourteen inches, or within a few hundredths
of an inch of fourteen. The immersion in water, with the
exception of the three last, was four inches, or two-fifths of the
width. The total depths were various, those bodies whose sides
projected outwards requiring greater depth than those with sides
inclining inwards; and for this reason, the edge of the former
when inclined becomes sooner level with the surface of the
water.

Fig. 1 has the sides parallel to the plane of the mast both
above and beneath the water line.

Fig. 2 has the sides projecting 15 degrees oitticard above the
water line, and parallel to the masts under.

Fig. 3 has the sides inclining inwards 15 degrees above the
water line, and parallel to the plane of the masts under.

Fig. 4 has the sides projecting outwards, and at equal incli-
nations (15 degrees both above and beneath the water line).

Fig. 5 has the sides inclining inwards and at equal inclina-
tions (15 degrees) to the plane of the masts above and below the
water line.

Fig. 6 has the sides coincident with the surface of a cylinder,
the vertical sections being equal circles.

Fig. 7 has the vertical sections terminated by the arcs of a
parabola.

Figs. 8, 9, 10, refer to the experiments made on the greatest
vertical section (or midship bend) of an 18 gun brig, the Leopard
of 50 guns, and the Howe of 120 guns.

In fig. 1 (Plate XXVI), B A is the surface of the water when
the vessels float upright. C H the water line when they incline
30 degrees. E refers equally to the centres of gravity of the
displaced fluid when the figure floats horizontally, and to the
models in the first set of experiments. G is the centre of gravity
of the model in the second set of experiments ; the distance EG
being 1 "3 inches, or -±g^ of the breadth BA; E R, and G r, are
the lever on which the water acts to re-establish the vessel in a
vertical position. M is the meta centre, or point below which
the vessel's centre of gravity ought always to be situated to
prevent its oversetting.

The displaced water, as well as the weights applied to incline

1824.] Stability of Floating Bodies. 83

the vessel, were calculated in ounces, drachms, and scruples,
and afterwards reduced to the decimal parts of an ounce, three
scruples in this case being equal to one drachm.

Example 1. — Model 1. — Experiment 1. — The total depth of
the model being 7*1 inches, the height of the centre of gravity-
is subtracted in each experiment, and the length of the mast
(measuring from the centre of gravity of the model to the apex),
20*96 inches being afterwards added, gives the length of lever
at which the weights are applied to produce the various inclina-
tions of 5° 10°, 15°, 20°, 25°, and 30°, Ther. The centre of
gravity in Exper. 1 being situated two inches above the bottom
of the model, and coinciding with the centre of gravity of the
displaced fluid, the weight 2*2239 oz. being applied to the mast
will incline it 5°. It is obvious that to restore the vessel to its
original vertical position, the momentum of the water must be
equal to that of the inclining power. If, therefore, the momen-
tum of the effort to incline the vessel (that is to say, the weight
applied, multiplied by the length of the mast) be divided by the
weight of the displaced water, the quotient will be the length of
lever E R on which the water acts.

Experiment 1. — Model 1, inclined 5°. — The inclining weight
is 2*2239 ounces, the length of lever 26-06 inches, and weight

of the displaced water 324*52 ounces, then = *18

or E R. By proceeding in a similar manner, the length of lever
is obtained for 10°, 15°, 20°, 25°, and 30°. It should be men-
tioned, that after the vessel had been inclined on one side, it
was turned and inclined on the other, by which means if the
mast was not perpendicular, or there was any inaccuracy in the
form of the model or manner of placing the ballast, it was imme-
diately perceived, and the error corrected in taking the mean of
the two experiments. The difference, however, seldom amounted
to two drachms, and in general was much less.

The result of the second set of experiments proved the accu-
racy of the first, the altitude of the point M being nearly the
same in both cases, as may be seen on reference to the annexed
tables.

Column 1 shows the angles of inclination. Columns 2 and 6,
the weights that produced that inclination. Columns 3 and 7,
the length of lever E R and G r. Columns 4 and 8, the lever
E R and G r, calculated by Mr. Atwood's theorem. Columns
5 and 9, the height of the point, M above the point E, and
found in the following manner : — As the sine of the inclination
: E R or G r : : radius : EM or G M. When the centres of
gravity of figs. I and 7 coincide with the centres of gravity of
the displaced fluid, their stability, allowing for the attendant
inaccuracy of experiments, will be the same as shown by the
subjoined calculations.

g2

10

0-36

X

324-52

15

0-55

X

324-52

20

0-75

X

324-52

25

0-97

X

324-52

30

1-22

X

324-52

0-26

X

215-97

-s

56

0-53

X

215-97

—

115

0-81

X

215-97

ss

175

Ml

X

215-97

^—.

240

1-45

X

215-97

—

313

1-83

X

215-97

=

395

84 Col. Beanfoy on the [Feb.

5 0-18 x 324-52 = 58

117
178
243
315
396

Figs. 8, 9, 10, are the greatest vertical sections of three men
of war.

The object in making these experiments was to determine
how much the meta centres of these parts of the ships are
elevated above the load water line. Each figure was submitted
to two experiments, for determining the height of the meta
centre above the centre of gravity of the displaced fluid. These
two were then added together, and the draught of water sub-
tracted. For instance, the 18 gun brig 3-22 inches, the mean
height of the meta centre (see Table VIII and Exper. 1) above
the point E, being added to 2*24 inches. The centre of gravity
gives 5*46 inches, from which deduct 3*60 the draught of water,
and the remainder 1*86 will be the quantity sought. The beam
of a man of war of this size is 30 feet, and -fe%%- °f 30 is 5*58
feet, which is the height of the brig's meta centre above the
water when inclined between 15° and 20°. (See Table VIII.)

The mean height of the Leopard's meta centre above the
centre of gravity of the water is 2-38, to which add 2-38, and
from the total subtract 4-13, the remainder y %\ is the distance
of the meta centre above the line of floatation, or T gg-^ parts of
the breadth. The beam or greater breadth of this 50 gun ship
is 39^ feet, T ^ s - of 39^-, is 2-49 feet, the meta centre's height,
which point may be considered as stationary.

The mean height of the meta centre of the Howe above the
centre of gravity of the displaced water is 2-26 inches, to which
add 2-43, and deduct 4'27 (the draught of water). The remainder
-^y- parts of an inch is the meta centre's altitude above the
water, or -^-5- of the width. The greatest breadth of the 120 gun
ship is 54 feet 5 inches, or 54-417 ; T f^ of 54-417 is 2-27 feet,
the Howe's meta centre above the load water line. The meta
centre being stationary, proves that the midship bends of the
Howard and Leopard are in great measure circular.

The centre of gravity of the displaced water of the men of
war was determined mechanically, and the columns in the tables
headed Theor. are not filled up, it being impossible to give any
o-eneral rule for finding the centre of gravity of bodies formed
by different curves or mixed lines.

Although the theory of stability is perfect, yet the calculations
are attended with considerable trouble, especially in complex
forms, such as the hulls of ships, which require the labour of
months. Under these circumstances is not the mechanical

1824.] Stability of Floating Bodies. 85

method adopted in these experiments of finding the meta centre
by first suspending the model on pivots, and then inclining it
in water by weight, the preferable mode of proceeding ? I have
reason to believe that with proper attention, and provided the
pivots turn on friction rollers, the centre of gravity could be
ascertained within the hundredth part of an inch.

A most essential point in ship building is the framing and
putting together of the materials. This is now so well performed
through the eminent skill and superior abilities of Sir Robert
Seppings, as to render it doubtful whether this branch of naval
mechanism admits of further extension. These observations,
however, will not apply to another subject of naval science.
Indeed it seems scarcely credible that in the first maritime
nation in the world, one whose very existence depends upon its
shipping, and upon the building of whose men of war millions
and hundreds of millions have been expended from the time of
Henry VIII. to the present day, no series of experiments on the
resistance of fluids should have been undertaken by authority.
Should this unaccountable neglect be palliated by the trite
remark, that that which is found to answer in smooth water is
inapplicable to rough, it may be answered, that Emerson in his
octavo book of Mechanics, p. 113, speaking of a watch keeping-
time at sea, declares that " to suppose any regular motion can
subsist among ten thousand irregular motions, and in ten thou-
sand different directions, is a most glaring absurdity," yet not-
withstanding the prediction of this celebrated writer, chronome-
ters are found to be of most essential use, and as such taken on
board most ships of value. Vessels propelled by steam how
cross from Falmouth to Spain and back, yet not many years
have elapsed since this mode of navigation was declared utterly
impracticable.

The expence of making a complete set of experiments proba-
bly would not exceed the value of the main mast of a single line
of battle ship ; and a more convenient and eligible situation for
conducting such experiments cannot be found than the King's
Dock Yard at Woolwich. Such an undertaking is absolutely
necessarv for discovering the solid of the least resistance, and
for the improvement of the hulls of vessels ; and when the
immense importance is considered of so easy and indispensable
an elucidation of this interesting but ill understood branch of
physics, it is hoped that the naval administration of my Lord
Melville, which has already done so much for the promotion of
science, will not consider the resistance of fluids as unworthy of
notice. Every member of the community must participate in a
wish that his Lordship may be pleased to issue directions for
prosecuting an inquiry, of which the success cannot be doubted,
if the investigation be committed to the skill, science, and .teal,
wltich at present distinguish the Navy Office.

86

Col. Beaufoy on the
Table I.

[Feb.

Model 1.
Weight of water displaced 324-52 ounces.

Exp. 1.

Lever 26*06 inches.

Centre of gravity 2 inches.

Exp. 2.

Lever 24*76 inches.

Centre of gravity 33 inches.

Deg.

Oz. | ER

Theor.

M C

Oz.

Gr.

Theor.

M C

5
10
15

20
25
30

2-2239 | 0-18
4 4635 0-36
6-8437 j 0-55
9-2942 0-75
12 089 0-97
15156 1-22

0-18
0-37
0-56
076
0-97
1-22

205
2-06
2-12
2-18
2-30
2-43

0.8333
1-7569
2-7777
3-9583
5-4202
7-2464

0-06
013
021
0-30
041
0-55

0-07
014
0-22
0-31
0-42
0-56

203
2-07
2-12
218
2-28
2-41

1

2 1 3

4

1 5

6

7

8

9

Table II.

Model 2.
Weight of water displaced 324-52 ounces.

Exp. 1.

Exp. S

Lever 26-66 inches.

Lever 25-36 inches.

Centre of gravity

I inches.

Centre of gravity 3-3 inches.

Deg.

Oz.

ER

Theor.

MC

Oz.

Gr.

Theor.

MC

5

2-2135

0-18

018

2-09

0-8137

006

0-07

2-06

10

4-5000

0-37

0-41

212

1-8437

0-18

0-18

2-13

15

7 0208

0-58

0-59

2-23

3-0156

0-23

0-25

2-21

20

97187

0-80

0-82

2-3:1

4-5156

0-35

0-37

2-33

25

12-932

1-06

1-08

2-51

64219

0*50

0-53

2-49

30

16-661

1-37
3

1-38

2-74

90625

0-71

0-73

2-72

1

2

4

5

6

7

8

9

Table III.

Model 3.
Weight of water displaced 324-52 ounces.

Exp. 1.

Exp. 2.

Lever 26-10 inches.

Lever 24-80 inches.

Centre of gravity

2 inchet.

Centre of gravity 3-3 inches.

Deg.

Oz. ER

Theor.

31 C

Oz.

Gr.

Theor.

MC

5

2-1929 1 01 8

0-18

2-02

0-8177

006

0-06

202

10

4-3073

0-35

0-35

1-99

1-5677

012

013

1-99

15

6-4062

0-52

0-53

1-99

2-3335

0-18

0-20

1-99

20

85312

0-67

0-71

2-01

3- 1667

0-24

0-26

2-01

25

10-797

0-87

0-89

2-05

4-1198

0-31

0-34

2-04

30

13-203

1-06

1-08

2 12

5-2604

0-40

0-43

2-10

1

2

3

4

5

6

7

8 9

1824.]

Stability of Floating Bodies.
Table IV.

87

Model 4.
Weight of water displaced 359-14 ounces.

Exp. 1.

Exp.

2.

Lever 26-71 inches.

Lever 25*41 inches.

Centre of gravity

1-93 inch.

Centre of gravity

3-23 inches.

Deg.

Oz.

ER

Theor.

MC

Oz.

Gr.

Theor.

M C

5

2-1937

0-16

017

380

0-6094

0-04

0-06

3-73

10

4-56?5

0-34

0-35

3-88

1*5260

Oil

01 2

3-85

15

73229

054

0-56

4-03

2-8177

0-20

0-23

400

20

10-458

0-78

0-77

4-20

46469

0-32

0-33

417

25

14-427

1-07

109

4-47

7-0104

0-50

0-54

4-40

30

19-260

1-43

1-43

4-79

10417

0-74

0-78

4-70

1

2

3

4

5

6

7

8

9

Table V.

Model 5.
Weight of water displaced 289-96 ounces.

Exp. 1.

Lever 26-03 inches.

Centre of gravity 2-06 inches

Exp. 2.

Lever 24-73 inches.
Centre of gravity 3-36 inches.

Deg.

Oz.

ER

Theor. | M C

Oz.

Gr.

Theor.

M C

5
10
15
20
25
30

2- 1302
4-1823
6-0937
80104
9-9583
11-875

0-19
0-37
055
0-72
0-89
1-07

0-20
0-37
57
074
0-91
109

2-19
2-16
2-11
2-10
211
213

0-9375
1-7448

2-4896
3-2083
3-9896
4-7812

0-08
15
021
0-27
034
0-41

0-08
0-14
0-23
0-29
036
0-44

2-22
2-16
2-12
210
210
212

1

2

4

4

5

6

7

8

9

Table VI.

Model 6.
Weight of water displaced 240-74 ounces.

Exp. 1.

Exp.

2.

Lever 25-73 inches.

Lever 24-33 inches.

Centre of gravity 2-33 inches

Centre of gravity 3'63 inches.

Deg.

Oz.

21719

E R

Theor.

MC

Oz.

Gr.

Theor.

M C

5

0-23

0-24

2-66

1-1667

0-12

0-l.t

2-65

10

4-3177

0-46

048

2-66

2-3229

0-23

0-26

2-65

15

6-4271

0-69

0-72

2-65

3-4114

0-34

0-37

2-66

20

8-4687

0-90

096

2-65

4-4896

0-45

0-51

2-63

25

10-547

112

1-18

2-66

5-5808

0-56

0-63

B-04

30

12583
2

1-34

1-40

2-69

6-5417

0-66

75

2-62

1

3

4

5

6

7

M

9

Col. Beaufoy on the
Table VII.

[Feb.

Model 7.
Weight of water displaced 215*97 ounces.

Exp. 1.

Exp. 2.

Lever 27*08 inches.

Lever 25*78 inches.

Centre of gravity

2*4 inches.

Centr

e of gravity 3*7 inches.

Deg.

Oz.

ER

Theor.

M C

Oz.

Gr.

Theor.

M C

5

2*1021

0-26

0-27

3*02

1 -2708

0*21

016

304

10

4*2375

0-53

0-55

306

2*5835

0*31

0*32

3 07

15

6-4666

0*81

0-84

313

3-9687

0-47

0*50

3-13

20

8-8646

111

1-14

3*25

5*5469

0*66

0*69

3*24

25

11-588

1*45

1-46

3-44

7*4427

0*89

0*91

3*40

30

14-568

1*82

1-83

3-65
5

9*7864

117

117

3*64

1

2

3

4

6

7

8

9

Table VIII.

18 Gun Brig.

Weight of water displaced 1 86*96 ounces.

Exp. 1.

Exp. 2.

Lever 25-35 inches.

Lever 24*05 inches.

Centre of gravity 2*24 inches

Centre of gravity 3*54 inches.

Deg.

Oz.

ER

Theor.

MC

Oz.

Gr.

Theor.

MC

5

2-1146

0*29

3-29

1*3626

0-19

3*31

10

4-1979

57

3-28

2-6667

0-34

3-27

15

6-1823

0-84

3-24

3-9271

0*50

325

20

80521

1*09

319

5-0417

0-65

3*20

25

9-8958

1*34

3-17

6*0989

0-78

3*17

30

11-635

1*58

Mean

3-15

71146

0-91

Mean

313

1

2

3

3-22

6

7

3-22

4

5

8

9

Table IX.

Leopard of 50 guns.
Weight of water displaced 271-71 ounces.

Exp. 1.

Exp.

2.

Lever 26-15 inches.

Lever 24-85 inches.

Centre of gravity 2-38 inches

Centre of gravity 3-68 inches.

Deg.

Oz.

ER

Theor.

MC

Oz.

Gr.

Theor. | M C

5

2-1562

0-21

2*38

1-0260

09

2*38

10

4*2500

041

2*36

2-0000

0-18

2-35

15

6*3750

0-61

2-37

3-0417

0*28

2-37

20

8*4583

0*81

2*38

4-0573

0-37

2-38

25

10-536

1*01

2*40

5*0573

0*46

2*39

30

12-510

1-20

Mean

2-41

5-9375

0-54

Mean

2-39

1

2

3

2-38

6

7

2*38

4

5

8

9

1824.]

Stability of Floating Bodies.
Table X.

89

Howe of 120 guns.
Weight of water displaced 285-97 ounces.

Exp. 1.

Lever 26-13 inches.

Centre of gravity 2-43 inches

Exp. 2.

Lever 24-83 Inches.

Centre of gravity 3-73 inches.

Deg.

Oz.

ER

Theor.

M C

Oz.

Gr.

Theor.

MC

5
10
15
20
25
30

2-1458
4-2760
6-3802
8-4062
10-495
12-500

0.20
0-39
0-58
0-77
0-96
1-15

Mean

2-25
2-25
2-25
2-24
2-27
2-29

0-9635
1-9062
2-8281
3-7552
4-6458
5-5669

0-08
016
0-24
0-33
0-40
0-48

Mean

2-26
2-25
2-25
2-25
2-25
2-27

1

2

3

2-26

6

7

2-26

4 5

8

9

Article II.

On the Liquefaction of Chlorine and other Gases. By M. Fara-
day, Chemical Assistant in the Royal Institution.*

I took advantage of the late cold weather (Feb. and March,
1823), to procure crystals of hydrate of chlorine for the purpose
of analysis. The results are contained in a short paper in the
Quarterly Journal of Science, vol. xv. Its composition is very
nearly 27*7 chlorine, 72*3 water, or 1 proportional of chlorine,
and 10 of water.

The President of the Royal Society having honoured me by
looking at these conclusions, suggested, that an exposure of the
substance to heat under pressure, would probably lead to inte-
resting results : the following experiments were commenced at
his request. Some hydrate of chlorine was prepared, and being
dried as well as could be by pressure in bibulous paper, was
introduced into a sealed glass tube, the upper end of which was
then hermetically closed. Being placed in water at 60°, it
underwent no change ; but when put into water at 100°, the
substance fused, the tube became filled with a bright yellow
atmosphere, and, on examination, was found to contain two fluid
substances : the one, about three-fourths of the whole, was of a

» Abstracted from two papers in the Phil. Trans, for 1823, Part II.

90 Mr. Faraday on the [Feb.

faint yellow colour, having very much the appearance of water ;
the remaining fourth was a heavy bright yellow fluid, lying at
the bottom of the former, without any apparent tendency to mix
with it. As the tube cooled, the yellow atmosphere condensed
into more of the yellow fluid, which floated in a film on the pale
fluid, looking very like chloride of nitrogen ; and at 70° the pale
portion congealed, although even at 32° the yellow portion did
not solidify. Heated up to 100° the yellow fluid appeared to
boil, and again produced the bright coloured atmosphere.

By putting the hydrate into a bent tube, afterwards hermeti-
cally sealed, I found it easy, after decomposing it by a heat of
100°, to distil the yellow fluid to one end of the tube, and so
separate it from the remaining portion. In this way a more
complete decomposition of the hydrate was effected, and when
the whole was allowed to cool, neither of the fluids solidified at
temperatures above 34°, and the yellow portion not even at 0°.
When the two were mixed together, they gradually combined at
temperatures below 60°, and formed the same solid substances
as that first introduced. If, when the fluids were separated, the
tube was cut in the middle, the parts flew asunder as if with an
explosion, the whole of the yellow portion disappeared, and
there was a powerful atmosphere of chlorine produced ; the pale
portion on the contrary remained, and when examined, proved
to be a weak solution of chlorine in water, with a little muriatic
acid, probably from the impurity of the hydrate used. When
that end of the tube in which the yellow fluid lay was broken
under a jar of water, there was an immediate production of
chlorine gas.

I at first thought that muriatic acid and euchlorine had been
formed ; then, that two new hydrates of chlorine had been pro-
duced ; but at last I suspected that the chlorine had been
entirely separated from the water by the heat, and condensed
into a dry fluid by the mere pressure of its own abundant vapour.
If that were true, it followed, that chlorine gas, when com-
pressed, should be condensed into the same fluid, and, as the
atmosphere in the tube in which the fluid lay was not very yel-
low at 50° or 60°, it seemed probable that the pressure required
was not beyond what could readily be obtained by a condensing
syringe. A long tube was therefore furnished with a cap and
stop-cock, then exhausted of air and filled with chlorine, and
being held vertically with the syringe upwards, air was forced
in, which thrust the chlorine to the bottom of the tube, and gave
a pressure of about four atmospheres. Being now cooled, there
was an immediate deposit in films, which appeared to be hydrate,
formed by water contained in the gas and vessels, but some of
the yellow fluid was also produced. As this however might
also contain a portion of the water present, a perfectly dry tube
and apparatus were taken, and the chlorine left for some time

1824.] Liquefaction of Chlorine and other Gases. 91

over a bath of sulphuric acid before it was introduced. Upon
throwing in air and giving pressure, there was now no solid film
formed, but the clear yellow fluid was deposited, aud more
abundantly still upon cooling. After remaining some time it
disappeared, having gradually mixed with the atmosphere above
it, but every repetition of the experiment produced the same
results.

Presuming that I had now a right to consider the yellow fluid
as pure chlorine in the liquid state, I proceeded to examine its
properties, as well as I could when obtained by heat from the
hydrate. However obtained, it always appears very limpid and
fluid, and excessively volatile at common pressure. A portion
was cooled in its tube to 0° : it remained fluid. The tube was
then opened, when a part immediately flew off, leaving the rest
so cooled by the evaporation as to remain a fluid under the atmo-
spheric pressure. The temperature could not have been higher
than — 40° in this case ; as Sir Humphry Davy has shown that
dry chlorine does not condense at that temperature under com-
mon pressure. Another tube was opened at a temperature of
50° ; a part of the chlorine volatilised, and cooled the tube so
much as to condense the atmospheric vapour on it as ice.

A tube having the water at one end and the chlorine at the
other was weighed, and then cut in two ; the chlorine imme-
diately flew oft", and the loss being ascertained was found to be
1*6 grain : the water left was examined and found to contain
some chlorine : its weight was ascertained to be 5*4 grains.
These proportions, however, must not be considered as indica-
tive of the true composition of hydrate of chlorine ; for, from
the mildness of the weather during the time when these experi-
ments were made, it was impossible to collect the crystals of
hydrate, press, and transfer them, without losing much chlorine ;
and it is also impossible to separate the chlorine and water in
the tube perfectly, or keep them separate, as the atmosphere
within will combine with the water, and gradually reform the
hydrate.

Before cutting the tube, another tube had been prepared
exactly like it in form and size, and a portion of water introduced
into it, as near as the eye could judge, of the same bulk as the
fluid chlorine : this water was found to weigh 1*2 grain ; a result,
which, if it may be trusted, would give the specific gravity of
fluid chlorine as 1*33 ; and from its appearance in, and on water,
this cannot be far wrong.

The refractive power of fluid chlorine is rather less than that
of water. The pressure of its vapour at GO is nearly equal to
four atmospheres.

92 Mr. Faraday on the [Feb.

[Note on the Condensation of Muriatic Acid Gas into the liquid
Form. By Sir H. Davy, Bart. Pres. RS.

In desiring Mr. Faraday to expose the hydrate of chlorine to
heat in a closed glass tube, it occurred to me, that one of three
things would happen ; that it would become fluid as a hydrate ;
or that a decomposition of water would occur, and euchlorine and
muriatic acid be formed ; or that the chlorine would separate in
a condensed state. This last result having been obtained, it
evidently led to other researches of the same kind. I shall hope,
on a future occasion, to detail some general views on the subject
of these researches. I shall now merely mention, that by seal-
ing muriate of ammonia and sulphuric acid in a strong glass tube,
and causing them to act upon each other, I have procured liquid
muriatic acid: and by substituting carbonate for muriate of
ammonia, I have no doubt that carbonic acid may be obtained,
though in the only trial I have made the tube burst. I have
requested Mr. Faraday to pursue these experiments, and to
extend them to all the gases which are of considerable density,
or to any extent soluble in water ; and I hope soon to be able to
lay an account of his results, with some applications of them that
I propose to make, before the Society.

I cannot conclude this note without observing, that the gene-
ration of elastic substances in close vessels, either with or with-
out heat, offers much more powerful means of approximating
their molecules than those dependent upon the application of
cold, whether natural or artificial : for, as gases diminish only
about 1-480 in volume for every — degree of Fahrenheit's scale,
beginning at ordinary temperatures, a very slight condensation
only can be produced by the most powerful freezing mixtures,
not half as much as would result from the application of a strong
flame to one part of a glass tube, the other part being of ordi-
nary temperature : and when attempts are made to condense
gases into fluids by sudden mechanical compression, the heat,
instantly generated, presents a formidable obstacle to the success
of the experiment ; whereas, in the compression resulting from
their slow generation in close vessels, if the process be conducted
with common precautions, there is no source of difficulty or dan-
ger ; and it may be easily assisted by artificial cold in cases
when gases approach near to that point of compression and tem-
perature at which they become vapours.]

The refractive power of liquid muriatic acid is greater than
that of nitrous oxide, but less than that of water; it is nearly
equal to that of carbonic acid. The pressure of its vapour at the
temperature of 50° is equal to about 40 atmospheres.

1824.] Liquefaction of Chlorine and other Gases. 93

Sulphurous Acid.

Mercury and concentrated sulphuric acid were sealed up in a
bent tube, and, being brought to one end, heat was carefully
applied, while the other end was preserved cool by wet bibulous
paper. Sulphurous acid gas was produced where the heat acted,
and was condensed by the sulphuric acid above ; but, when the
latter had become saturated, the sulphurous acid passed to the
cold end of the tube, and was condensed into a liquid. When
the whole tube was cold, if the sulphurous acid were returned
on to the mixture of sulphuric acid and sulphate of mercury, a
portion was re-absorbed, but the rest remained on it without
mixing.

Liquid sulphurous acid is very limpid and colourless, and
highly fluid. Its refractive power, obtained by comparing it in
water and other media, with water contained in a similar tube,
appeared to be nearly equal to that of water. It does not soli-
dify or become adhesive at a temperature of 0° F. When a tube
containing it was opened, the contents did not rush out as with
explosion, but a portion of the liquid evaporated rapidly, cooling
another portion so much as to leave it in the fluid state at com-
mon barometric pressure. It was however rapidly dissipated,
not producing visible fumes, but producing the odour of pure
sulphurous acid, and leaving the tube quite dry. A portion of
the vapour of the fluid received over a mercurial bath, and exa-
mined, proved to be sulphurous acid gas. A piece of ice drop-
ped into the fluid instantly made it boil, from the heat communi-
cated by it.

To prove in an unexceptionable manner that the fluid was pure
sulphurous acid, some sulphurous acid gas was carefully pre-
pared over mercury, and a long tube perfectly dry, and closed at
one end, being exhausted, was filled with it ; more sulphurous
acid was then thrown in by a condensing syringe, till there were
three or four atmospheres ; the tube remained perfectly clear and
dry, but on cooling one end to 0°, the fluid sulphurous acid con-
densed, and in all its characters was like that prepared by the
former process.

A small gage was attached to a tube in which sulphurous acid
was afterwards formed, and at a temperature of 45° F. the pres-
sure within the tube was equal to three atmospheres, there being
a portion of liquid sulphurous acid present : but as the common
air had not been excluded when the tube was sealed, nearly one
atmosphere must be due to its presence, so that sulphurous acid
vapour exerts a pressure of about two atmospheres at 45° F. Its
specific gravity was nearly 1*42. # ,

• I am indebted to Mr. Davics Gilbert, who examined with much attention the
results of these experiments, for the suggestion of the means adopted to obtain the spe-
cific gravity of some of these fluids. A number of small glass bulbs were blown and
hermetically scaled ; they were then thrown into alcohol, water, sulphuric acid, or mix-

94 Mr. Faraday on the [Feb.

Sulphuretted Hydrogen.

A tube being bent, and sealed at the shorter end, strong
muriatic acid was poured in through a small funnel, so as nearly
to fill the short leg without soiling the long one. A piece of
platinum foil was then crumpled up and pushed in, and upon
that were put fragments of sulphuret of iron, until the tube was
nearly full. In this way action was prevented until the tube
was sealed. If it once commences, it is almost impossible to
close the tube in a manner sufficiently strong, because of the
pressing out of the gas. When closed, the muriatic acid was
made to run on to the sulphuret of iron, and then left for a day
or two. At the end of that time, much protomuriate of iron had
formed, and on placing the clean end of the tube in a mixture of
ice and salt, warming the other end if necessary by a little water,
sulphuretted hydrogen in the liquid state distilled over.

The liquid sulphuretted hydrogen was colourless, limpid, and
excessively fluid. Ether, when compared with it in similar
tubes, appeared tenacious and oily. It did not mix with the
rest of the fluid in the tube, which was no doubt saturated, but
remained standing on it. When a tube containing it was opened,
the liquid immediately rushed into vapour ; and this being done
under water, and the vapour collected and examined, it proved
to be sulphuretted hydrogen gas. As the temperature of a tube
containing some of it rose from 0° to 45°, part of the fluid rose
in vapour, and its bulk, diminished ; but there was no other
change : it did not seem more adhesive at 0° than at 45°. Its
refractive power appeared to be rather greater than that of
water ; it decidedly surpassed that of sulphurous acid. A small
gage being introduced into a tube in which liquid sulphuretted
hydrogen was afterwards produced, it was found that the pres-
sure of its vapour was nearly equal to 17 atmospheres at the
temperature of 50°.

The gages used were made by drawing out some tubes at the
blowpipe table until they were capillary, and of a trumpet form ;
they were graduated by bringing a small portion of mercury
successively into their different parts ; they were then sealed at
the fine end, and a portion of mercury placed in the broad end ;
and in this state they were placed in the tubes, so that none of
the substances used, or produced, could get to the mercury, or

tuies of these, and when any one was found of the same specific gravity as the fluid in
which it was immersed, the specific gravity of the fluid was taken : thus a number of
hydrometrical bulbs were obtained ; these were introduced into the tubes in which the
substances were to be liberated ; and ultimately, the dry liquids obtained, in contact
with them. It was then observed whether they floated or not, and a second set of expe-
riments were made with bulbs lighter or heavier as required, until a near approximation
was obtained. Many of the tubes burst in the experiments, and in others difficulties
occurred from the accidental fouling of the bulb by the contents of the tube. One source
of error may be mentioned in addition to those which are obvious, namely, the alteration
of the bulk of the bulb by its submission to the pressure required to keep the substance
in the fluid state.

1824.] Liquefaction of Chlorine and other Gases. 85

pass by it to the inside of the gage. In estimating the number
of atmospheres, one has always been subtracted for the air left
in the tube.

The specific gravity of sulphuretted hydrogen appeared to
be 0-9.

Carbonic Acid.

The materials used in the production of carbonic acid, were
carbonate of ammonia and concentrated sulphuric acid ; the
manipulation was like that described for sulphuretted hydrogen.
Much stronger tubes are however required for carbonic acid than
for anv of the former substances, and there is none which has
produced so many or more powerful explosions. Tubes which
have held fluid carbonic acid well for two or three weeks toge-
ther, have, upon some increase in the warmth of the weather,
spontaneously exploded with great violence; and the precau-
tions of glass masks, goggles, &c. which are at all times neces-
sary in pursuing these experiments, are particularly so with car-
bonic acid.

Carbonic acid is a limpid colourless body, extremely fluid,
and floating upon the other contents of the tube. It distils
readily and rapidly at the difference of temperature between 32°
and 0°. Its refractive power is much less than that of water.
No diminution of temperature to which I have been able to sub-
mit it, has altered its appearance. In endeavouring to open the
tubes atone end, they have uniformly burst into fragments, with
powerful explosions. By inclosing a gage in a tube in which
fluid carbonic acid was afterwards produced, it was found that
its vapour exerted a pressure of 36 atmospheres at a temperature
of 32°.

Euchlorine.

Fluid euchlorine was obtained by inclosing chlorate of potash
and sulphuric acid in a tube, and leaving them to act on each
other for 24 hours. In that time there had been much action,
the mixture was of a dark reddish brown, and the atmosphere of
a bright yellow colour. The mixture was then heated up to
100°, and the unoccupied end of the tube cooled to 0°; by degrees
the mixture lost its dark colour, and a very fluid ethereal looking
substance condensed. It was not miscible with a small portion
of the sulphuric acid which lay beneath it ; but when returned
on to the mass of salt and acid, it was gradually absorbed,
rendering the mixture of a much deeper colour even than itself.

Euchlorine thus obtained is a very fluid transparent sub-
stance, of a deep yellow colour. A tube containing a portion of
it in the clean end, was opened at the opposite extremity ; there
was a rush of euchlorine vapour, but the salt plugged up the
aperture : while clearing this away, the whole tube burst with a
violent explosion, except the small end in a cloth in my hand,

96 Mr. Faraday on the [Feb.

where the euchlorine previously lay, but the fluid had all disap-
peared.

Nitrous Oxide.

Some nitrate of ammonia, previously made as dry as could be
by partial decomposition, by heat in the air, was sealed up in a
bent tube, and then heated in one end, the other being preserved
cool. By repeating the distillation once or twice in this way, it
was found, on after-examination, that very little of the salt
remained undecomposed. The process requires care. I have
had many explosions occur with very strong tubes, and at consi-
derable risk.

When the tube is cooled, it is found to contain two fluids, and
a very compressed atmosphere. The heavier fluid on examina-
tion proved to be water, with a little acid and nitrous oxide in
solution ; the other was nitrous oxide. It appears in a very
liquid, limpid, colourless state ; and so volatile that the warmth
of the hand generally makes it disappear in vapour. The appli-
cation of ice and salt condenses abundance of it into the liquid
state again. It boils readily by the difference of temperature
between 50° and 0°. It does not appear to have any tendency
to solidify at — 10°. Its refractive power is very much less
than that of water, and less than any fluid that has yet been
obtained in these experiments, or than any known fluid. A
tube being opened in the air, the nitrous oxide immediately burst
into vapour. Another tube opened under water, and the vapour
collected and examined, it proved to be nitrous oxide gas. A
gage being introduced into a tube, in which liquid nitrous oxide
was afterwards produced, gave the pressure of its vapour as equal
to above 50 atmospheres at 45°.

Cyanogen.

Some pure cyanuret of mercury was heated until perfectly
dry. A portion was then inclosed in a green glass tube, in the
same manner as in former instances, and being collected to one
end, was decomposed by heat, while the other end was cooled.
The cyanogen soon appeared as a liquid : it was limpid, colour-
less, and very fluid ; not altering its state at the temperature of
0°. Its refractive power is rather less, perhaps, than that of
water. A tube containing it being opened in the air, the expan-
sion within did not appear to be very great ; and the liquid
passed with comparative slowness into the state of vapour, pro-
ducing great cold. The vapour, being collected over mercury,
proved to be pure cyanogen.

A tube was sealed up with cyanuret of mercury at one end,
and a drop of water at the other ; the fluid cyanogen was then
produced in contact with the water. It did not mix, at least in
any considerable quantity, with that fluid, but floated on it,
being lighter, though apparently not so much so as ether would

1824.] Liquefaction of Chlorine and other Gases. 97

be. In the course of some days, action had taken place, the
water had become black, and changes, probably such as are
known to take place in an aqueous solution of cyanogen,
occurred. The pressure of the vapour of cyanogen appeared by
the gage to be 3-6 or 3*7 atmospheres at 45°. Its specific
gravity was nearly 0*9.

Ammonia.

In searching after liquid ammonia, it became necessary,
though difficult, to find some dry source of that substance; and
I at last resorted to a compound of it, which I had occasion to
notice some years since with chloride of silver.* When dry
chloride of silver is put into ammoniacal gas, as dry as it can be
made, it absorbs a large quantity of it : 100 grains condensing
above 130 cubical inches of the gas ; but the compound thus
formed is decomposed by a temperature of 100° F. or upwards.
A portion of this compound was sealed up in a bent tube and
heated in one leg, while the other was cooled by ice or water.
The compound thus heated under pressure fused at a compara-
tively low temperature, and boiled up, giving off ammoniacal gas,
which condensed at the opposite end into a liquid.

Liquid ammonia thus obtained was colourless, transparent,
and very fluid. Its refractive power surpassed that of any other
of the fluids described, and that also of water itself. From the
way in which it was obtained, it was evidently as free from water
as ammonia in any state could be. When the chloride of silver
is allowed to cool, the ammonia immediately returns to it, com-
bining with it, and producing the original compound. During
this action a curious combination of effects takes place : as the
chloride absorbs the ammonia, heat is produced, the tempera-
ture rising up nearly to 100° ; while a few inches off, at the
opposite end of the tube, considerable cold is produced by the
evaporation of the fluid. When the whole is retained at the
temperature of 60°, the ammonia boils till it is dissipated and
re-combined. The pressure of the vapour of ammonia is equal
to about 6*5 atmospheres at 50°. Its specific gravity was 0*76.

Attempts have been made to obtain hydrogen, oxygen,
fluoboracic, fluosilicic, and phosphu retted hydrogen gases
in the liquid state ; but though all of them have been sub-
jected to great pressure, they have as yet resisted conden-
sation.

Article III.

New Locality of the Skorodite. By W. Phillips, FLS. MGS.&c.

Tut: crystals forming the subject of this notice were lately
received in a letter addressed to me from " Calenick, near
Truro," and signed "J. Michell," us having been "obtained

• Quarterly Journal of Science, vol. v.\>- 71.

New Series, vol. vii. h

98 Mr. W. Phillips on Skorodite. [Feb.

from a mine in the neighbourhood of St. Austell," in Cornwall.
By the gentleman who transmitted them, they are imagined to
be a variety of the arseniate of iron ; but he laments that their
scarcity had prevented his ascertaining their composition, and
requests the insertion of a notice respecting them in the Annals
of Philosophy.

The largest of these crystals does not exceed in size the head
of an ordinary pin, but many of them are so complete as to leave
it a matter of doubt whether they ever were attached to a
matrix ; a few, however, are deposited on some small fragments
of quartz. In form they very closely resemble that of the skoro-
dite, given in the third edition of my Elementary Introduction
to Mineralogy ; the planes rfe and d>' , are, however, wanting in
the second of the following figures, which represents the form of
the crystals lately received from Cornwall ; while almost every
one of them exhibits the planes c c, which are not observable in
the crystals of the skorodite, or in those of the martial arseniate
of copper.

Externally these crystals are of the dark
bottle-green colour, very common to some of
the prismatic varieties of the arseniate of cop-
per ; but this is not in fact the true colour of the
substance itself, which, on holding the crystals,
or thin fragments of them between the eye and
the light, is found by the assistance of a glass
to be of the pale blue, so common to the mar-
tial arseniate of copper. The dark-green
colour arises from the mechanical intermixture
of a multitude of very minute specks, of that
colour, visible on the surface, and also by
transmitted light.

M on M 120°

MonA 119

Mondi 141

d\ on dv 103

d\ ondi" 112

c on h 154

The first figure represents a right rhombic prism, the primary form of the martial
arseniate of copper, the skorodite, and also of the crystals which form the subject of this
notice : the planes d\ , d\ , of the latter, generally present several reflections less than one
degree apart, indicating each to be a series of planes.

The foregoing measurements by the reflective goniometer, as
well as the form of these crystals, tend to show that they are only
a variety of the martial arseniate of copper, which commonly is
prismatic, the planes of the prism being the primary planes
M M', sometimes associated with the planes^/' and h, and the
prism is commonly terminated by one quadrangular pyramid
formed by the planes dd' ; but in these crystals, and also in the
skorodite, the planes M M' are reduced to small triangles,
owing to the presence of both pyramids.

The martial aiseniate of copper, and its variety the skorodite,

2'
55

45
36
20

1824.] Mr. R. Phillips's Chemical Examination of Skorodite. 99

yield to mechanical division parallel to the planes M M', and
also to the plane h of the preceding figure ; the latter being
parallel to the lesser diagonal of the prism ; a fragment found
among the crystals received from Cornwall, exhibits the latter
cleavage with a tolerably brilliant surface ; the former I have not
succeeded in obtaining, owing, perhaps, to the minuteness of the
crystals rendering it difficult to operate upon them, and to the
intermixture of the green particles.

On subjecting these crystals to the action of the blowpipe,
copious arsenical fumes are given off, without altering the exter-
nal form, which, however, is rendered of an ochreous colour.

Chemical Examination of the Skorodite. By R. Phillips, FRS.

A few crystals of the skorodite were dissolved in nitric acid,
the solution was decomposed by potash, and after having satu-
rated the alkali with acetic acid, nitrate of silver was added,
which immediately gave the well-known red precipitate indicat-
ing the presence of arsenic acid.

The precipitate separated by potash from solution in nitric
acid appeared to consist of peroxide of iron ; but in order to
ascertain whether it contained oxide of copper, it was put into
ammonia; this however exhibited, no appearance of having dis-
solved any of the oxide in question. I subsequently dissolved
some of the skorodite in nitric acid, and tried whether polished
iron would detect the presence of copper, but the attempt was
equally unsuccessful as the first. In order to be perfectly satis-
fied that the substance contained no copper, I requested Mr.
Children to submit it to examination ; the results of his experi-
ments confirmed those which I had obtained, and proved that
no copper was present.

Through the kindness of Mr. Heuland, I was enabled to sub-
mit some crystals of foreign skorodite to examination, and these,
as well as some with which my brother supplied me', were totally
destitute of copper, and appeared to consist entirely of arsenic
acid and oxide of iron.

On account of the similarity of crystalline form and measure-
ments in the skorodite and the martial arseniate of copper, analyzed
by M. Chenevix, 1 was desirous of subjecting the latter to a fresh
examination ; in so doing I had very satisfactory evidence that.
it contained a considerable portion of oxide of copper. The
analysis of M. Chenevix gives:

Arsenic acid 33*5

Oxide of iron 27 # .'j

Oxide of copper 22-:')

Water 120

Silica 3-0

98-5
h 2

100 Mr. Smithson on [Feb.

Supposing that the iron and copper exist in the mineral in the
state of peroxide, and that the weights of their atoms are to each
other respectively as 40 to 80, it will be impossible to reduce the
martial arseniate of copper to a probable definite compound ; for
it will appear by calculation that the nearest approximation is
5 atoms of oxide of iron and 2 atoms of oxide of copper ; it
seems, therefore, more likely that the skorodite is a peculiar
arseniate of iron, differing not only in form, but in composition,
from the cubic arseniate of iron; and it will follow, if this be
admitted, that the martial arseniate of copper is a mixture and
not a compound of arseniate of iron and arseniate of copper :
this supposition will, perhaps, be considered the more probable
when it is remembered that the cubic arseniate of iron contains
9 per cent, of oxide of copper. It is also to be observed, that
M. Chenevix inclines to the opinion that it is a mixture of the
two arseniates ; and lastly, there appears to be no reason why
there should not exist several varieties of arseniate of iron, which
is well known to be the case with arseniate of copper.

Article IV.

On some Compounds of Fluorine. By J. Smithson, Esq. FRS.
(To the Editor of the Annals of Philosophy .)

SIR, Jan. 2, 1824.

When numberless persons are seen, in every direction, pur-
suing a subject with the utmost ardour, it is natural to conclude
that their labours have accomplished all that was within their
reach to perform.

It must, therefore, in mineralogy be supposed, that those sub-
stances whose abundance has placed them in every hand, have
been fully scrutinized, and are thoroughly understood ; and that
if now to extend the boundaries of the science it is not indis-
pensable to explore new regions of the earth, and procure mat-
ters hitherto unpossessed, it is yet only to objects the most rare,
the most difficult of acquisition, that inquiry can be applied with
any hope of new results.

A want of due conviction that the materials of the globe and
the products of the laboratory are the same, that what nature
affords spontaneously to men, and what the art of the chemist
prepares, differ no ways but in the sources from whence they are
derived, has given to the industry of the collector of mineral
bodies an erroneous direction.

What is essential to a knowledge of chemical beings has been
lsft in neglect ; accidents of small import, often of none, have

1824.] some Compounds of Fluorine. 101

fixed attention — have engrossed it ; and a fertile field of disco-
very has thus remained where otherwise it would have been
exhausted.

Fluor spar has decorated mineral cabinets from probably the
earliest period of their existence ; every tint with which chance
can paint it; each casual diversity of form and appearance under
which it may present itself have been long familiar, and its true
nature continues a problem ; and its decomposition by fire was
yet to be learned.

Fluor Spar.

If a very minute fragment of fluor spar is fastened by means
of clay* to the end of a platina wire nearly as fine as a hair,
which is the size I now employ even with fluxes, it will be per-
ceived on the first contact of the fire tc melt with great facility.
As the fusion is prolonged, the fusibility will decrease ; protube-
rances will rise over the surface of the ball ; it will put on what
is designated by the term of the cauliflower form ; and finally
become entirely refractory. On detaching it from the wire, it
will prove hollow. This little capsula being taken up again by
its side, and its edge presented to the flame, thin and porous as
this edge is, it will withstand its utmost violence.

Such an alteration of qualities proclaims an equal one of
nature. I had no doubt that the calcium had absorbed oxygen,
and parted with fluorine ; that the mass had ceased to be fluor
spar, and was become quicklime. On placing it in a drop of
water my conjecture was confirmed ; a solution took place by
which test papers were altered ; a cremor calcis soon appeared ;
and on allowing the mixture to become spontaneously dry, a
white powder remained, which acids dissolved with effervescence.

That the fluoric element was gone admitted not of doubt. To
pursue it in its escape ; to coerce it, and render it palpable to the
senses, could not be required to establish the fact. It may,
however, be done.

The open tube described by M. Berzelius in his valuable work
on the blowpipe, is adapted to the purpose by an addition to it.
A small plate of platina foil, on a curved plate of baked clay, is
introduced a little way into one of its ends ; and secured by

X-_jJ

bringing with the point of the flame the glass into contact with
it. The body to be tried is fixed to this plate by means of moist
clay ; and may then be subjected for any time to any degree of
heat.

Thus tried, fluor spar quickly obscured the glass by a thick
crust of siliceous matter ; and coloured yellow a bit of paper
tinged with logwood.

* AnnaU for December.

Mr. Smithson on

[Feb.

102

M. Berzelius assigns fernambuc wood for the test of fluoric
acid. Bergman says that this wood affords a red infusion
which alkalies turn blue.* None such could be procured, but it
was found that logwood might be substituted for it. The paper
tinged with this, like that mentioned by M. Berzelius, is made
yellow by fluoric acid and oxalic acid; but it did not seem to be
so by sulphuric or muriatic acids, nor by phosphoric acid.

Topaz.

In extremely minute particles, topaz subjected to the fire at
the end of a very slender wire soon becomes opaque and white ;
but I perceived no marks of fusion.

This change is undoubtedly occasioned by the loss of its
fluoric part. One of the times I was at Berlin, M. Klaproth gave
me, as his reason for not publishing the analysis of topaz, that
in the porcelain furnace it sustained a great loss of weight, the
cause of which he had not then been able to ascertain.

Topaz ground to impalpable powder, and blended with car-
bonate of lime, melted with ease. Some of this mixture fused
on the platina plate at the mouth of the tube, made an abundant
deposit of silica over its interior surface ; and the bit of logwood
paper at the end of it had its blue colour altered to yellow.

In the trial in this way of substances of difficult fusion, an
apparatus of the following construction is more favourable than
the one above described.

a. A bottle coik.

It. A slice of the same fixed with three pins.

c. A wire.

* Analysis of Mineral Waters.

1824.] some Compounds of Fluorine. 103

d. A cylinder of platina foil introduced into the mouth of the
glass tube, to prevent its being softened and closed by the
flame.

e. A platina wire, at the end of which is cemented with clay
the subject of trial.

I formerly suggested that topaz might be a compound of sili
cate of alumina, and of fluate of alumina.* I am now con-
vinced that no oxygen exists in it ; but that it is a combination
of the fluorides of silicium and aluminum.

This system produces a considerable alteration in the propor-
tions of its elements.

The mean of the six analyses quoted by M. Haiiy, in the
second edition of his Mineralogy, is

Silica 36*0

Alumina 52'3

Fluoric acid 9"7

98-0

Deducting the oxygen from the metals, we have

Silicium 18*0

Aluminium 27'7

Fluorine 52-3

S8-U
Kri/olite.

It has been observed to diminish in fusibility during fusion,f
and it was in every respect probable, from what had been seen
with the foregoing bodies, that it would be decomposed in the
fire. After being kept some time melted, it afforded an alkaline
solution, which, by exposure to the air, became carbonate of
soda, effloresced, effervesced with nitric acid, and produced
crystals of nitrate of soda.

Fused on the platina plate at the mouth of the tube, a copious
deposit of silex collected in the tube ; and the bit of logwood
paper became very yellow.

Kryolite heated in sulphuric acid on glass destroyed its
polish.

1. These experiments render it highly probable that fluorine
will be expelled from every compound of it by the agency of fire ;
and consequently that we are now in possession of a general
method of discovering its presence in bodies. In cases where
a matter is infusible, and parts with it with great difficulty, as in

* Philosophical Transactions for 1811.
t Hatty's Mineralogy.

104 Mr. Smithson on [Feb.

that of topaz, it may be required to reduce it to fine powder, or
to act upon it by some admixture with which it melts, for the
sake of promoting division, and multiplying surfaces.

Hereby is supplied what may have seemed to be an omission
in the paper on acids.* Although it was not such, siuce fluorine
is not an acid ; and fluoric acid may never occur in a mineral
substance ; as it can probably exist in combination only with
ammonia ; all its other supposed compounds being doubtless
fluorides.

2. The theory of these decompositions may be acquired by
experiment; and light obtained on the nature of the compounds.

If fluor spar, for instance, is a combination of oxide of calcium
and fluoric acid, and this is expelled from the oxide merely by
the force of fire, the decomposition of it will take place in closed
vessels without the presence of oxygen or of water ; fluoric acid
will be obtained ; and the weight of this acid and the lime will
be equal together to that of the original spar.

If the spar is metallic calcium and fluorine, and when heated
in oxygen absorbs this, and parts with fluorine, it is fluorine
which will be collected in the vessels, and its weight and that of
the lime will together exceed that of the spar by the oxygen of
the lime.

If it is water which is the agent of decomposition, fluoric acid
will be collected ; but here the excess of weight will not only
equal the oxygen absorbed by the lime, but also the hydrogen
which has acidified the fluorine ; and this increased weight of
the fluoric acid will prove that hydrogen is an element of it.

It appears to have been fluoric acid which in the above related
experiments passed into the tubes ; but the inflammable matter
of the flame would probably have rendered emitted fluorine such.
It becomes of high importance to ascertain whether ignited fluor
spar is decomposed by passing water over it, and if so what are
the products. It is not convenient to myself at present to make
the experiment : I therefore resign it to others.

How far the difficulty which the action of fluorine on the ves-
sels in which it is contained, as opposed to its examination,
would be obviated by employing vessels of its compounds, as of
fluor spar, or of chloride of silver ; or whether it acts on all
oxides as it does on silica, experiments have not informed me.

3. The vegetation of matters before the blowpipe is attributed
by a great chemist to " a new state of equilibrium induced by
heat between the constituent parts of bodies,"f but the pheno-
mena do not accord with the explanation.

Was such the cause of the acquired infusibility, it would ma-
nifest itself through the whole mass as soon as fusion had
enabled the new arrangement. It is, on the contrary, confined
to the surface ; the interior portion continues fluid ; but where-

• jlnnah for May.

•f De l'Emploi du Chalumeau, p. 94.

1824.] some Compounds of Fluorine. 105

ever any of this bursts the shell, and issues forth, it is instantly
fixed in immovable solidity ; and when the process has attained
its final state, a hollow globule remains.

Why is the change of quality limited to the surface ; how has
been produced the central cavity; what has forced away the
matter which occupied it ? A new element has been received
from without, one which existed in the matter has been parted
with in a state of vapour. This double action may probably be
inferred wherever a matter presents this species of vegetation.

Some metallic bodies, as tin, lead, sulphuretted tin, arsenic-
ated nickel, 8cc. present another species of vegetation, caused by
the absorption of oxygen, and the production over their surface
of a matter more bulky than the metal from which it is produced,
and infusible at the heat to which it is exposed. Here no inter-
nal void forms.

The mode of fusion of epidote had led me to suspect the
existence of fluorine in it ; but on trial with the second appara-
tus, represented above, I could not perceive a trace of it. A
more accurate observation of its fusion has shown me that it
does not, as generally supposed, form the cauliflower. It
appears to do so only where so large a mass is exposed to the fire
that but points of its surface are fused in succession. If a very
minute bit is employed, it is clearly seen to puff up like borax,
stilbite, &c. ; and then, like them, become less fusible; from the
separation, doubtless, of a vapourized element on which its
greater fusibility had depended. The smallest particle of fluor
spar shows no such inflation.

We see here three several cases of intumescence in the fire :
one where a gas is absorbed ; one where a gas, or vapour, is
disengaged ; one where the two effects are concomitant.

There may be persons who, measuring the importance of the
subject by the magnitude of the objects, will cast a supercilious
look on this discussion ; but the particle and the planet are sub-
ject to the same laws ; and what is learned upon the one will be
known of the other.

Article V.

On the Composition of the Ancient Ruby Glass,
By Mr. J. T. Cooper.

(To the Editor of the Annals of Philosophy.)

SIR, Jan. 11, 1824.

The chief difference between the ancient and modern ruby
glass, I have understood from those who are in the habit of using
the latter in large quantities, consists in the hardness, or infusi-

106 On the Composition of the Ancient Ruby Glass. [Feb.

bility of the basis on which it is flashed, that which is now manu-
factured being of flint, while the former is of the hardest crown
glass; also the difficulty of obtaining it of any size, and free from
cloudiness or opacity : to ascertain the composition of the
ancient glass, I made the following experiments.

A quantity of the glass was sent me by Mr. Charles Muss, and
such pieces were selected for examination as were free from
decomposition, and of the deepest colour: these were powdered
in a stone mortar, and afterwards mixed with four times
their weight of carbonate of potash ; the mixture was heated to
fusion in a hessian crucible, and the fusedmass poured out while
fluid. This was afterwards powdered and digested in muriatic
acid, which dissolved nearly the whole, what remained appear-
ing to be mostly silex. The acid solution was slowly evaporated
nearly to dryness, and distilled water poured on the mass,
to wash it. To the filtered solution ammonia was added
in excess, which threw down an abundant precipitate of
oxide of iron, the supernatant fluid acquiring a deep blue tinge,
which, upon examination, proved to contain only copper.
The filter that contained the silex stood for some hours near a
window, and the surface of the silex gradually assumed a deeper
colour, approximating at last to a deep brown. Suspecting it to
contain muriate of silver, I washed it with a solution of ammonia.
On adding muriatic acid to the filtered solution, a copious preci-
pitate of chloride of silver ensued.

The precipitate of iron, and the ammoniacal solution containing
the copper, were carefully examined for other substances, and
particularly for manganese, which I know has been suspected to
enter into the composition of this coloured glass, but 1 was not
able to detect the smallest portion. The only substance I found,
except those I have mentioned, was a slight trace of lime.
From the above, it is evident the composition of this glass may
be stated to be

Silex,

Oxide of copper,

Oxide of iron,

Oxide of silver,

Lime.

It is difficult to decide whether the oxide of iron enters into
the composition of the coloured portion of the glass, or into
the bases or substance of it, or both. I detached some small
fragments of the uncoloured portion, and made a separate exa-
mination of them, and they proved to contain abundance of iron.
It is also difficult to determine what alkali has been used as
a flux for the siliceous matter. The quantity of lime I obtained
was certainly much too small to produce the effect, but I have
some reason to suspect the alkah to be soda.

To endeavour to determine the exact proportions of the above

1824.] Mr. Baily on the ensuing Opposition of Mars. 107

colouring ingredients, which I consider to be the oxide of cop-
per and the oxide of silver, would be useless. The colouring
matter which forms only a film of at most l-200th of an inch in
thickness upon a substance of glass varying from l-30th to l-10th
of an inch, is quite sufficient reason for desisting. I attempted some
time since to grind the uncoloured portion away ; and in another
instance, to detach it by fluoric acid, but in each of these
attempts I was unsuccessful. That class of your readers to
whom this communication may be of any service, if not fully
aware of the proportions of the colouring oxides, may easily
obtain them by a few experiments.

Article VI.

On the ensuing Opposition of Mars. By F. Baily, Esq. FRS.
VP. Ast. !Soc. (Read before the Astronomical Society of
London, Jan. 9, 1824.)*

At a time when we have two new and excellent observatories
established in the southern hemisphere, where the celestial phe-
nomena are watched and observed with the greatest diligence
and zeal, it becomes the more important and necessary that
corresponding observations of a certain class of those pheno-
mena, of not very frequent occurrence, should also be made in
the northern hemisphere, by such persons as are fortunately pos-
sessed of the requisite means for this purpose. Without this
co-operation, -the labours of those industrious observers will lose
much of their value, and the advantageous opportunity of eluci-
dating an important branch of physical astronomy will be
wholly lost to the public.

The ensuing opposition of Mars, on the 24th of March, is one
of this class : a phenomenon which occurs once only in a period
of about 780 days. It is well known that corresponding obser-
vations of this planet, in the two hemispheres, as compared with
stars situated near its path, about the period of its opposition,
will serve to determine its parallax. And the parallax of Mars
being known, that of the sun may thence be deduced. This was
the plan adopted by Lacaille, when he was at the Cape of Good
Hope, in the year 1751 ; since which period, the method has
fallen into disuse for want of an observatory in the southern
hemisphere, with instruments fit to be compared with those in
Europe.

The present period seems extremely favourable (for the reasons
above mentioned) for the revival of this method. At the time of

• See our report of the proceedings of this Society in the present Number. — EdU.

108 Mr. Baity on the ensuing Opposition of Mars. [Feb.

the last opposition in 1822, I ventured to draw the public atten-
tion to the subject, by pointing out certain stars, near which the
planet would pass ; and with the positions of which it might be
compared. Several valuable observations were made both in the
southern and in the northern hemisphere, which are published
in various periodical works ; and which being thus recorded,
may be referred to with advantage, by those who devote them-
selves to this branch of physical astronomy.

At the present opposition, there are but few stars, and those of
inferior magnitude, with which Mars can be advantageously
compared. For ten days preceding and subsequent to the date
of its opposition, Mars will not approach near to any star given
in the large catalogues of Bradley or Piazzi. There are, however,
five stars given in the catalogues of Lalande, inserted in the
Connaissance des Terns for the years VIII. and XIII. with which
the comparisons may be made. The mean places of these stars,
on Jan. 1 of the present year, are given in the following little
table ; together with the dates when Mars will be in conjunction
with them.

Con. des tems.

Mag.

7~~8

8

8

7
6, 7

AR.

D.

Mars.

An. XIII.

XII.

XIII.

VIII.

XIII.

12" 10™ s
14 29
17 16
20 8
29 56

2° 18' 44" N
1 52 2
1 29 47
1 8 37
6 44

April 1

March 29

27

25

19

When Mars approaches either of these stars, the observer
should, with a micrometer, measure their distance, in a direct
line, or take the differences, in right ascension and declination,
between the planet and the star ; the place and the correct time
of observation being noted down.

Accurate observations of this kind are of great importance in
astronomy ; and as nothing tends so much to further such objects
as a previous announcement of the phenomena about to take
place, I trust I need not make any apology for drawing the atten-
tion of the members of this Society to so interesting a subject.

The diameter of Mars, on the day of opposition, will
be 13-91".

1824.] M. Keferstein's Table of the Salt Springs in Germany. 109

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] 824.] M. Keferstein's Table of the Salt Springs in Germany. 1 13

The different formations yield the following proportions of salt :

1. Granite and slate formation :

Lasts of salt at Bex 425

Moutiers 400

825

2. Porphyry and coal formation.

Lasts of salt at Munster on the Stein . . 270
Theodorshall 880

1150

3. " Rothe sandstein formation" (red dead lier).

Lasts of salt at Mossbach 100

Weissbach 75

Deirkbeck ^ —

175

4. Zechstein, or alpenkalkstein formation {new magnesian
limestone).

Lasts of salt at Frankenhausen 2000

Fried richshall 3750

Offenau . —

Hall, in Wurtemberg . . 2450
Sulz on the Necker . . . 200

Ludvvigshall 3750

Durrheim —

Reichenhall 15,500

Luneberg 7200

34,850

5. Bunter sandstein formation (new red sandstone).

Lasts of salt at Durrenberg 6500

Artern 1450

Stassurth 1500

Teuditz and Kotsehau. . 480

Koesen 1340

Salzgitter . . . . , 350

Salzdettfurth 170

Salzderhelden 350

Sulbeck 425

Bodenfelde 300

Schoningen 280

Salzdahlum 209

Neio Series, vol. vn. i

1 14 M. Keferstein's Table of the Salt Springs in Germany. [Feb.

Lasts of salt at Carlshaven 300

Allendorf 4100

Schmalkalden 300

Nauheim 3200

Salzhausen 112

Weissenheim 85

Budingen 75

Homburg 100

Soden 100?

Kissingen 500

Orb 600

Phillipsthal 500

Salzungen 3000

Glucksbrunn 250

26,567

5. Jungere kalk, between the bunter sandslein and the ter-
tiary formations.

(a.) From the muschelkalk.

Lasts of salt at Halle, in Saxony .... 6300

Schonebeck 15000

Sulze 800

Lindenau 25

Julius Hall 14

22,139

b. Gryphiten kalk in Germany.

Lasts of salt at Rolching 33

Reine 330

Rehme 700

Rothenfelde 1200

Hegersen 120

Grossen Reiden 180

Munder 45

Salzhemmendorf 1400

Salz Uffeln 500

4508

c. Gryphiten kalk in Alsace.

Lasts of salt at Dieuze and Mojensie. 10,000

Chateau Salins 2870

Lons le Saunier 720

Salins 3030

Vic —

16,620

1824.] Mr. Smithson on some Egyptian Colours. 115

d. Green sand and chalk.

Lasts of salt at Kotiigsborn near Unna. 3027

• Werl 900

Sassendorf, near Soest. 640

Westerkatten 500

Salzkatten 600

6. Tertiary formations.

a. Sand formation (London clay).

5667
48,934

Lasts of salt at Colberg 1500

Greifsvvalde 300

Oldesloe 1200

Sulz, in Mecklenburg. . 440
Sulz, in Hanover ...... 100

3540

b. Mergel sandstein (gres a lignites according to Hum-
boldt), from which arise the salt springs in Hungary,
Gallicia, and the territory of Siebenburg, which yield,

in lasts of salt, above 225 000

Lasts of salt from the granite and slate formation *828

Lasts from the porphyry and coal formation \ \ 150

Lasts from the great older sandstone formation ; — viz'.

the red sandstone (roth todt liegendes), and that which

lies between the hunter sandstein and the zechstein. . 01 592

Lasts from the newer limestones, viz. the muschelkalk

(lias), the gryphiten kalk and Jura kalk (oolite series),

and the chalk , 40 q~a

Lasts from the tertiary formations, viz. the plastic clay

(bra unkoh leu format.) and London clay (sand format.) 228,540

Article VIII.

An Examination of some Egyptian Colours.
By James Smithson, Esq. FRS.

(To the Editor of the Annals of Philosophy.)

SIR ' Jan. 2, 182-J.

More than commonly incurious must he be who would not
hnd delight in stemming the stream of ages ; returning to times
long past, and beholding the then state of things and men.

In the arts of an ancient people much may be seen concei njng
them : the progress they had made in knowledge of various kinds-

i2

116 Mr. Smithson on some Egyptian Colours. [Feb.

their habits ; their ideas on many subjects. And products of
skill may likewise occur, either wholly unknown to us, or supe-
rior to those which now supply them.

I received from Mr. Curtin, who travelled in Egypt with Mr.
Belzoni, a small fragment of the tomb of King Psammis. It was
sculptured in basso relievo which were painted.

The colours were white, red, black, and blue.

I have heard the white of Egyptian paintings extolled for its
brilliancy and preservation. I found the present to be neither
lead nor gypsum ; but carbonate of lime. Chlorides of barium
caused no turbidness in its solution. An entire sarcophagus of
arragonite proves that the ancient Egyptians were in possession
of an abundant store of this matter, remarkable often for its
perfect whiteness. Was it the material of their white paint ?

The red was oxide of iron. By heating, it became black, and
returned on cooling to its original hue. In a case where so much
foreign admixture was present, since the layer of red was much
too thin to allow of its being isolated, I considered this as a bet-
ter proof of red oxide of iron than obtaining prussian blue.

The black was pounded wood charcoal. After the carbonate
of lime with which it was mixed had been removed by an acid,
the texture of the larger particles was perfectly discernible with
a strong lens ; and in the fire it burned entirely away.

The blue is what most deserves attention. Jt was a smalt, or
glass powder, so like our own, though a little paler, as to be
mistaken for it by judges to whom I showed it; but its tinging
matter was not cobalt, but copper. Melted with borax and tin,
the red oxide of copper immediately appeared.

Many years ago I examined the blue glass with which was
painted a small figure of Isis, brought to me from Egypt by a
relation of mine, and found its colouring matter to be copper.

I am informed that a fine blue glass cannot at present be
obtained by means of copper. What its advantages would be
above that from cobalt, it is for artists to decide.

Intent upon the blue smalt, it unfortunately did not occur to
me to examine, till I had washed nearly the whole of it away to
waste, what was the glutinous matter which had been so true to
its office for no less a period than 3,500 years ; for the colours
were as firm on the stone as they can ever have been.

A small quantity of it recovered from the water did not seem
to form a jelly on concentrating its solution ; or to produce a
precipitate with galls. I imagined its vegetable nature ascer-
tained by its ashes restoring the colour of reddened turnsol
paper, till I found those of glue do the same.

The employment of powder of charcoal for a black would seem
to imply an unacquaintance with lamp-black, and, perhaps, with
bone black, and that of copper to colour glass blue, a deficiency
of cobalt. And if the glutinous matter should prove, on a future
examination, to be vegetable, our glue being then possessed may,
perhaps, be deemed questionable.

1 824.] On the Crystalline Forms of Artificial Salts. 117

Article IX.

On the Crystalline Forms of Artificial Salts.
By H. J. Brooke, Esq. FRS.

(Continued from p. 22.)

Sulphate of Nickel and Copper.

The primary form of this salt is an oblique rhombic prism, with
an imperfect cleavage parallel to its lateral planes.

PonM,orM' 100° 15'

Pone' 117 30

M on M' 83 30

I received these crystals from Mr. R.
Phillips, and having dissolved some of
them in distilled water for the purpose of
obtaining others with more perfect planes,
I found that the first crystals deposited
from the solution were sulphate of' cop-
per ; the next, sulphate of nickel and
copper similar to those which had been

dissolved : these were removed, and were succeeded by a crop
of the same crystals intermingled with a few others of the
rhombic sulphate of nickel; and crystals of both these salts con-
tinued to be deposited together until the fluid was nearly all eva-
porated.

There were not any crystals of sulphate of copper deposited
from this solution after the double salt began to crystallize, but
the solution at Mr. P.'s, from which the crystals I received had
been obtained, had subsequently produced crystals of sulphate
of copper. It would appear from these circumstances that the
double salt would only be produced in uncombined portions of
both of the single ones.

Sulphate of Ammonia and Magnesia.

The primary form of this salt is an oblique rhombic prism.

P on M, or M' 104° 45'

Pone, ore' 154 40

Pong 135 40

Pone' 115 30

MonM' 109 30

M on k 125 15

The crystals of this and the following I
have received from Mr, R. Phillips.

118 Mr. W. Phillips on Cleavelandite. [Feb.

Sulphate of Copper and Potash.

The primary form is an oblique rhombic prism, and differing so
little from the preceding in measurement, that the same figure
may be used for both. The crystals do not appear to possess
any distinct cleavage.

P on M, or M' 104° 30'

P on e, or e' 154 20

Pone' 116 20

MonM' 107 35

Monk 126 12

Article X.

On the Occurrence of Cleavelandite in the older Rocks generally.
By W. Phillips, FLS. &c.

The discovery of cleavelandite as an ingredient in several
rocks of various and distant parts of England and Scotland, as
detailed in the Annals of November last, induced me to pursue
the subject further, from the notion that if this mineral should be
found only in particular descriptions of rocks, its presence, or
the contrary, might tend to throw some light on the difficult and
intricate inquiries connected with the comparatively relative ages
of the older rocks in general.

With this view I have examined rocks of different countries,
and although the examination has been limited to two or three
hours each evening for three or four weeks, it appears to me that
sufficient evidence has been obtained to evince the probability
that the presence of this mineral is almost universal in the older
rocks, and that it will frequently be found accompanying felspar
in them.

Of the rocks of Cornwall, the only one noticed in my former com-
munication was a porphyritic granite from Carnbrae ; I have since
found it intermingled with felspar, quartz, and mica, as the paste
of a porphyritic granite from Huel Gotland Mine, near St. Die, and
also in another from near the Land'? End ; in both the cleave-
landite is white and opaque, and the felspar translucent or trans-
parent. In a granite from Dartmoor, in Devonshire, consisting
chiefly of nearly opaque red felspar intermingled with hornblende
and quartz, the cleavelandite is translucent and slightly reddish,
and it bears but a small proportion to the felspar. It occurs
sparingly intermingled with felspar in the sienite of the Malvern
Hills. I have not succeeded in finding this substance as an
ingredient of any one of the numerous specimens in my posses-

1824.] Mr. W. Phillips on Cleavelandite. 119

sion from the porphyry or el van dykes of Cornwall ; the imbed-
ded crystals being all felspar.

This mineral appears to be the only substance connected with
hypersthene, in the hypersthene rock of Sky, for I have not been
able to detect any felspar in the several specimens of that rock
presented to me by L)r. Mac Culloch. I have detected it in
contact with felspar in some fragments of granites from Tiree,
presented to me for the purpose of examination by Capt. Vetch,
as were also others from the Shetland Isles, Fula and Faira, in
which also the cleavelandite occurs. To the same gentleman 1
am likewise indebted for a mass consisting of nearly white
lamellar felspar and green cleavelandite in about equal propor-
tions, simply adhering, not intermixed; as well as for an isolated
fragment about an inch and a half square, of the latter mineral Of
a dark colour, having greatly the aspect of felspar, its cleavage
planes being more than usually bright. Both these specimens
are from Tiree.

The presentation to me of a box of rock specimens from
Mont Blanc and its neighbourhood, by Charles Hampden Tur-
ner, Esq. with a catalogue " fourni par Joseph Marie Des-
champs, a Servoz, Canton de Chamouni," afforded a favourable
opportunity for their examination, especially as a large part of
them, indeed all in which I found the cleavelandite, are noted
in the catalogue as the " protogine granites of Jurine." In the
specimen of the very summit rock of Mont Blanc, cleavelandite
forms a considerable proportion, in connexion with steatite, talc,
quartz, chlorite, and felspar ; the cleavelandite being white,
nearly opaque, and often considerably granular : it occurs even
still more largely in the beautiful porphyritic granite ofPormenaz
about two miles W or NVV of Servoz, and in which the imbedded
substance is a felspar of a delicate rose colour ; the paste con-
sists of cleavelandite, quartz, felspar, hornblende, and chlorite,
and the aggregate is of a green colour. The rock of Vosa con-
sists of dark lamellar felspar, imbedded chiefly in yellow and
white cleavelandite including yellow mica. That of La Filla
consists of nearly white and opaque cleavelandite, mica, chlo-
rite, quartz, and felspar, and that of Brevent of the same sub-
stances. The rock of Des Trapettes consists chiefly of white
cleavelandite and white mica (it is elastic), containing spots of
yellow mica ; neither quartz nor chlorite is perceptible in it ;
and much of the cleavelandite has a granular aspect when
viewed in a direction contrary to that of the cleavage planes ;
two surfaces of this specimen are, however, coated by chlorite.

The only specimen of a rock in my possession from North
America, is one consisting chiefly of black mica, with which
transparent cleavelandite is intermixed ; garnets are imbedded
in it : this rock is from the banks of the Schuylkill, five miles W
of Philadelphia.

120 Mr. W. Phillips on Cleavelandite. [Feb.

In all the instances above enumerated, and in many more in
which I have failed to discover the cleavelandite, it will b^
understood that the means relied on for its detection were sim-
ply those of cleaving from the rock minute fragments, and sub-
mitting them to the reflective goniometer — a test it may be
assumed, sufficiently satisfactory, to render it needless to
have recourse to the labours of the chemist, where the
planes produced by cleavage are sufficiently bright, especially
since the angles at which the planes of the cleavelandite meet
each other are perfectly well ascertained, and essentially differ
from those of felspar, with which this mineral was always con-
founded, until the error was lately detected by the nearly simul-
taneous labours of Levy and Rose, and thereby furnishing
evidence (if indeed any were wanting) to the real value of the
mineralogical niceties belonging to cleavage and measurement,
and their essential importance to every one who would become
acquainted with the older rocks, which it may be said it is now
the fashion to neglect for the more inviting and less laborious
investigations requisite for the easier comprehension of the
newer.

It is scarcely needful to say, that whenever felspar is men-
tioned as an ingredient of the before mentioned rocks, its pre-
sence was always ascertained by the goniometer.

In several of the rocks of Mont Blanc and the neighbouring
mountains, it is however extremely difficult, if not impossible, to
decide whether one of their ingredients be felspar or cleavelan-
dite, without the assistance of the chemist, since the substance
in question is often either considerably granular, or approaches
the compact : sometimes, however, when that is the case, it
becomes manifest by a studious search that this appearance only
belongs to the cross fracture of the mineral, and that it does pos-
sess cleavages sufficiently distinct for the use of the goniometer ;
and in all cases where this has happened to me, the mineral has
proved to be cleavelandite, not felspar : in the specimen from the
Aiguille du Tour, which consists of a white granular substance
having some appearance of cleavage, and which is rendered
somewhat schistose by irregular layers of green chlorite, it is
impossible to decide on the nature of the white substance,
because the indications of cleavage are not sufficiently decisive
for the goniometer, but the examination of many rocks from the
neighbourhood leads to the conclusion that this substance is in
reality cleavelandite.

If we regard the elements of the several substances constitut-
ing the rocks in which both felspar and cleavelandite occur, as
having been in a state either of aqueous solution or of igneous
fusion ; that is to say, in a state in which the two alkalies enter-
ing separately into the composition of these two minerals, were
at liberty to exert their affinities for other bodies, it seems very

1824.] Col. Beaufoy's Astronomical Observations. 121

remarkable that they should each constitute separate minerals
in connexion with very nearly equal proportions of the same
earths — and as it occurred to me as being within the verge of
probability that these two alkalies might, by coalescing and
uniting themselves to the same or other earths, form another
compound body which would probably in that case have for its
primary form, one in which the planes would meet at angles
different to those either of felspar or cleavelandite, I have been
anxious to detect any such difference if it exists, but without
success ; for in every instance the angle obtained belonged to
the primary form either of the one or the other of the above-
mentioned mineral.

It may be added that although these minerals are sometimes
sufficiently distinct in the same specimen, there is no one cha-
racter belonging to either which adequately distinguishes it from
the other at first sight ; the most important feature is, that in
general the cleavage planes of felspar are more brilliant than
those of cleavelandite ; and hence it will be difficult hereafter to
describe a rock in which one of these minerals appears to be an
ingredient, without first having recourse either to the chemist or
the goniometer, in order to prove that it is not the other.

Article XI.

Astronomical Observations, 1823.
By Col. Beaufoy, FRS.

Basket/ Heath, near Stanmore.

Latitude 51° 37' 44'3" North. Longitude West in time 1' 20*93".

Dec. 30. Emersion of Jupiter's second J llh 33' 34" Mean Time at Bushey.

satellite ( 11 34 55 Mean Time at Greenwich.

Jan. 6. Emersion of Jupiter's first ^ 9 12 47 Mean Time at Bushey.

satellite < 9 14 08 Mean Time at Greenwich.

Jan. 1 1 . Emersion of Jupiter's first j 16 38 37 Mean Time at Bushey.

satellite ( 16 39 58 Mean Time at Greenwich.

Jan. 12. Occultation of a small star by < $ 5

the moon. Immersion (

Jan. 12. Emersion of Jupiter's third J 8 24 20 Mean Time at Bushey.

satellite } 8 25 41 Mean Time at Greenwich.

Jan. 13. Emersion of Jupiter's first? 11 08 14 Mean Time at Bushey.

satellite ( 11 09 34 Mean Time at Greenwich.

N. B. Jupiter's Limb was tremulous and ill defined.

122 Mr. Moyle on an Improvement in the Clinometer. [Feb.

Article XII.

On an Improvement of the Clinometer. By M. P. Moyle, Esq.
(To the Editor of the Annals of Philosophy.)

SIR, Helslon, Jan. I, 1824.

I have made an addition to the clinometer now generally in
use, which I flatter myself is an improvement; at least its utility
is more particularly felt in this neighbourhood by the superintend-
ants of mines in calculating the dip or underlie of a lode. Its
former construction pointed out only the angle from the horizon,
of any stratum, &c. I have now added another quadrant, on
which is delineated the number of feet and inches a lode will
underlie at certain angles in a fathom, perpendicular depth. The
following is an outline of the instrument.

I find the underlie of a lode of one foot in a fathom will be
indicated by an angle of 80^° from the horizon, six feet in a
fathom at the angle of 45°, and so on.

I am, Sir, your humble servant,

M. P. Moyle.

1824.] Mr. Grafs Reply to the Editor. 123

Article XIII.

Reply to the Review of Mr. Gray's Elements of Pharmacy.
By Mr. S. F. Gray.

(To the Editor of the Annals of Philosophy.)

SIR, 18, Burton-street, Burton Crescent, Dec. 23, 1823.

1 beg leave to thank you for the commendation you have
given to my Elements of Pharmacy, in saying that it is calcu-
lated to convey a considerable portion of information ; but I
must at the same time desire your attention to a few points in
the sequel of your review.

The arrangement is partly taken from Stahl, partly from Biot;
and is such as best suited my purpose of training the student to
scepticism, or, at least, indifference in theoretical points.

The definition to which you object is that of Black, with the
addition of the last clause, which I was induced to add, because
chemists, from the analogy of electricity to galvanism, attempt
to explain the phenomena of the former power, although it is not
produced by alteration of temperature, or mixture of bodies, but
by mere mechanical means, and therefore will not come within
the limits of the original definition of Dr. Black. Heat and cold
are used in the definition in their popular sense, as two contrary
powers, not only because the philosophical ideas of temperature
and caloric had not yet been mentioned ; but also because the
existence of a frigorific principle having been started, and its
partisans not yet extinct, the popular expression, which involves
no theory, best suited the cautious character of a sceptic.

The first error which you say you shall notice occurs in p. 95,
and after quoting the passage, you say, " it proves incontestably
that Mr. Gray is ignorant of the composition of sulphuric acid,
for he has once in words, and three times by symbols, misstated
its nature." But I believe you will upon reflection agree with
my statement, that sulphuric acid consists of a charge of sulphur
united with three of oxygen. I acknowledge that I have cer-
tainly erred in respect to oil of vitriol ; but having written ten for
one in the first instance, the subsequent repetitions were mere
slips of the pen. How easily these occur your own use of the
words sulphuric acid for oil of vitriol in this passage shows,
and we shall see more proofs hereafter. As it was only intended
in this place to explain the mode of using the symbols, the slip
is here of no consequence, and indeed it turns out better adapted
for that purpose than the truth would have done, as introducing
an example of a coefficient sign. In the history of oil of vitriol,
p. 138, the composition is stated right.

In commenting on my exposition of Berzelius's laws of com-

124 Mr. Gray's Reply to the Editor. [Feb.

bination, you object to my mentioning the speculations of that
chemist on the existence of oxygen in ammonia, in an element-
ary treatise. This is mere matter of opinion. Mr. Brande indeed
does not make any mention of the supposed compound nature
of nitrogen ; but both Mr. Henry (8th edit. vol. i. p. 243) and
Dr. Thomas Thomson (6th edit. vol. i. p. 214) not only notice
the suspicion of azotic gas, and ammoniacal gas containing oxy-
gen, but the one notices the ammonium of Sir H. Davy, and the
other the nitricum of Berzelius. So that I have just cause to be
astonished at your saying, " If the student after reading this
passage were to look into the chemical works of Thomson,
Henry, or Brande, he would find no mention either of oxygen

or nitricum existing in ammonia.

My idea of the composition of the liquor plumbi acetatis
agrees with the statements of Dr. Thomas Thomson, Mr. Henry,
Mr. Brande, and Mr. Anthony Todd Thomson. I am again
astonished at your saying, that " in p. 81 no rules are given for
describing those salts that contain an excess of base." I know
not how to account for this, unless by supposing a whole para-
graph has dropped out of your copy at press, as single letters
sometimes do ; for the third paragraph in that page, consisting
of no less than 14 lines, expressly relates to the mode of naming
(not indeed describing, as you have by another slip worded it)
salts when an acid combines in different proportions with the
same base, and five modes of nomenclature are related ; and
in the last paragraph of p. 94, the subject is resumed.

You then proceed to say (for I must now quote your words at
length), " On the same ground we object to the following state-
ment : Moist iodine added to phosphorus yields a sour colour-
less gas, which is rapidly absorbed by water, and must be
collected in a quicksilver apparatus ; a gallon of this gas weighs
about 311 grains. Here the changes are either I s + P into I 8
+ P 1 ; or I + P + H 1 into I H + P 1 , and the new acid is
called the iodic or hydroiodic." " The pupil would naturally
suppose that Mr. Gray considers the iodic or hydroiodic acids
(properly hydriodic) as similar ; but he ought to have known
that iodic acid consists of oxygen and iodine, and the hydriodic
acid of hydrogen and iodine ; it is the latter only which is
formed, excepting a quantity of phosphorous acid, of which no
notice is taken, nor is the decomposition of the water even hinted
at, although the formation of the hydriodic acid depends upon
it. (P. 166.)"

These are your precise words. I pass over any inquiry as to
the ground upon which you object to what I have said ; although
I am not able to discover any connexion between this passage
and that immediately preceding it, respecting the subsalts ; but
proceed to your assertion, that I have taken no notice of the
phosphorous acid which is formed. This shows how easily slips
of the pen may be made, and may abate your astonishment at a

1824.] Mr. Grafs Reply to the Editor. 125

slip of my own ; for here after you had twice copied from my
book the symbol for phosphorous acid, P l , as being a product
of this experiment, you assert, within the compass of only six
lines, that I have taken no notice of its production. Nor is this
all, for you go on to say I have not even hinted at the decompo-
sition of the water. Is it possible that the Editor of the Annals
of' Philosophy can be unable to read a chemical theorem
expressed in symbols 1 Upon no other ground can this censure,
and the one hitherto passed of my not knowing the difference
between iodic and hydroiodic (for so I shall continue to spell it)
acids, be explained. The two formulae I have given in symbols
express two theories of this experiment. The first I 3 , P chang-
ing into I' 2 , P 1 expressing that of Berzelius, in which iodine, I s ,
is considered as a superoxide of iodinum containing three
charges of oxygen, which, being acted upon by phosphorus, P,
a simple body transfers one charge of its oxygen to the phos-
phorus, forming phosphorous acid, P 1 , while the iodine having
of course only two charges of oxygen left united with it, is
changed into the iodic acid, P, of Berzelius, not of Gay-Lussac :
in this theory, the water is passive. The other formula I, P, H 1 ,
changing into I H, P 1 expresses the theory of Gay-Lussac.
Here iodine, I, and phosphorus, P, are both considered as sim-
ple bodies, and the water, H 1 , is active in the experiment, and is
indeed decomposed, its hydrogen, H, uniting with the iodine
and forming hydroiodic acid, I H, while its oxygen J- being thus
set free unites with the phosphorus and forms phosphorous acid,
P l . By this developement of the symbolic formulae, how little
cause there was for your censure is evident. As these experi-
ments on iodine are of no use in pharmacy, I should not have
mentioned them at all, leaving them to the pure chemists to
detail ; but that there existed a wide difference between the
views which Berzelius and Gay-Lussac have taken of the subject.
It was this slight connexion between them and the professed
object of my work, which caused me to express these incidental
matters in symbols, partly as an exercise to the student, and
partly because Berzelius's opinions on iodine, as detailed in the
Annals of Philosophy, have not been noticed in any of our ele-
mentary treatises on chemistry, and I was anxious that they
might be brought forward.

As to the use of the term hydroiodic acid, instead of hydrio-
dic, it may surely be justified by this single observation. The
union of hydrogen with chlorine produces, according to Gay-
Lussac's nomenclature, the hydrochloric acid ; with sulphur, the
hydrosulphuric acid ; — with tellurium, the hydrotelluric acid ; —
with cyanogen, the hydrocyanic acid ; — with phthore, the hydro-

Imthoric acid ; so strict analogy requires that the union of
lydrogen and iodine should produce the hydroiodic acid, and
our own language is not so rich in vowels that we can afford to

126 Mr. Gray's Reply to the Editor. [Feb.

reject those which are offered to our enjoyment. I have indeed
little doubt but that the term hydriodic was an accidental error
of Gay-Lussac, or of his printer, and has been perpetuated like
the etiolation of Fourcroy in his Systeme, instead of etoilation ;
or the laplysia of Linnaeus in his Systema Naturae, 12th edition,
instead of aplysia; which have been so often repeated, that they
are become standard errors, and bid fair to supplant the true
orthography, and disconcert the etymologists.

Your observations respecting arsenious acid are partly just;
the directions respecting testing for arsenic are, I confess,
imperfect and incorrect ; but it was not my intention to enter
upon the subject of forensic medicine ; and 1 have always taught
my own pupils that nothing short of the production of true
metallic arsenic will justify a medical practitioner to condemn a
supposed poisoner in cases which are in any way dubious.
Fortunately as arsenic is cheap, and almost always used by igno-
rant persons, they administer it in such quantities that dubious
cases seldom occur. I cannot, however, possibly conceive how
you could make the following assertion : — " Nor is the direct
evidence by metallization in any way alluded to," unless by again
supposing that another whole paragraph has, by some strange
fatality, dropped out at press from your copy ; for the very next
paragraph, in p. 151, to the one you quote, treats of the metalli-
zation of white arsenic by the addition of a subcarbonate of
potasse and charcoal dust.

Again passing over for a moment one of your observations, I
proceed to the concluding paragraph, which is indeed the cause
of my troubling you with this notice of your review. Man is
always subject to error, and therefore the mention of a few
errors in my Elements, which I am conscious must, like every
work hitherto published, or that ever will be published, contain
a few, and I hope but a few, would not have been any other way
noticed by me, but by silently amending them in any future
work. But I am charged with dividing chemists into rational
and irrational, and placing Sir Humphry Davy among the irra-
tional chemists. Now I think I may fairly challenge you to
produce the word irrational from any part of the book. A cau-
tious habit of distinction, that I have acquired, and of the want
of which in the generality of publishing chemists I have several
times complained, has led me to distinguish between pure che-
mists, pharmaceutical chemists, and I believe technical chemists,
not as words of reproach, but of distinction. So I have men-
tioned publishing chemists to distinguish them from mere
amateurs, or those who either labour only for themselves, or
thpse who are too modest to appear before the tribunal of the
public. And again in point of theory, every professor, and
indeed almost every chemist, has some peculiar doctrines of his
own ; but they may, and accordingly have been by me, divided

1824.] Mr. Gray's Reply to the Editor. 127

into two classes, according to the greater or less use they make
of analogical reasoning in their theories. Formerly from the
want of a sufficient number of facts, analogical reasoning was
the sole basis of chemical theory as may be seen in Beccher ;
by degrees direct evidence has been obtained on certain points,
but not yet on all. Berzelius and some others, among which,
did not my habitual indifferentism hinder me, I should rank, are
of opinion, that the analogical reasoning of our forefathers
should be retained so long as the facts which come to light can
possibly be explained by their hypotheses, and even in case this
can no longer be done, we should make as little change as possi-
ble. These are the chemists I have denominated rationals, not
from any superiority in understanding which they may claim,
but from their greater use of analogical reasoning than is
allowed by the opposite class ; analogical and rational being
constantly used in science as synonymous ; and the latter word
being best adapted to be used as a substantive. The peculiar
dogma of the other school is to reject all analogical reasoning,
and consider every body which has not yet been separated into
others as simple. To these chemists, which include the generality
of modern professors and authors, 1 have given not the name of
irrationals as you state, and which 1 expressly avoided lest I
should unintentionally offend, but that of Epicureans ; because
Rouelle, who may be considered as the father of the sect, is said
to have inscribed on the walls of his lecture room, a saying
ascribed to Epicurus ; That we can know only what we perceive
by our senses.

No man has a higher respect for Sir Humphry Davy, as a
chemist, than myself. Of his two precursors in the same path,
Homberg and Scheele, it is only the latter that can enter into
any competition with him; and if the Pomeranian exceeds in the
number of new substances he has discovered, the Englishman
has by far the advantage in the greater practical advantages to
be derived from his labours.

As to my opinion, however, of Lavoisier, which I have defer-
red to this place, it is unaltered by your remarks. He indeed
turned chemistry upside down, and he has shown us that the
phenomena of chemistry may be explained by thus reversing its
former theory, but theories are such tottering things that I do
not consider this as any great feat. I still deny that chemistry
is deeply indebted to him, in any other way than that the total
change he proposed, coinciding with the political circumstances
of the times, was brought into more notice than it would other-
wise have obtained, and thus it became necessary for the culti-
vators of chemistry either to defend the old doctrines, or
advocate the new : and in this manner indeed he has indirectly
been of the greatest service to it. How often are his experi-
ments referred to? Seldom: — I might say never. Are they
considered as examples of the most scrupulous accuracy like

128 Mr. JR. Phillips's Remarks [Feb.

those of Cavendish ? Far from it. That you may not suppose
this is only my own prejudiced opinion, I refer you to the
opinion expressed by Dr. Thomas Thomson in his catalogue of
Lavoisier's writings, in the second volume of the Annals of
Philosophy. I remain, Sir, yours respectfully,

Samuel F. Gray.

Article XIV.
Remarks upon the preceding Answer. By R. Phillips, FRS. &c.

(To Mr. Gray.)

SIR,

In the observations which I shall offer on your reply, I shall
confine myself as much as possible to matters of fact. I must,
however, confess, that I was completely in error respecting your
motive for adopting the arrangement which I criticised. Had I
known that you were assembling gum arabic, horns, henbane
leaves and eggs, as " farinaceous bodies," for the purpose of
exhibiting an absurdity, I should have congratulated you on the
success of your exertions ; but I think you should have ren-
dered your motive evident ; for the reader may imagine that you
are so unhappily circumstanced as really to suppose that eggs
are farinaceous, and oyster shells combustible.

I know not from whence you have copied the definition of
chemistry which you attribute to Dr. Black ; there are two defi-
nitions given in his lectures, and both so unlike that which you
ascribe to him, that neither contains the word " cold."

You admit that you have four times misstated the composition
of sulphuric acid, by assigning it ten atoms of water instead of
one atom ; but you say, that in p. 138 it is stated right. On
referring, I find that it " is supposed to consist of S* + water."
Now, according to the theory of " slips," of which you have
made so much use, I would ask, whether the pupil having four
times learned that oil of vitriol contains 10 atoms of water, he
would not be likely to conclude that at p. 138 the coefficient had
slipped out, rather than thatithad three times previously slippedinl
According, however, to Berzelius S 3 ■+• water, would express a
compound of three atoms of sulphur •+• one atom of water ; so
that I deny you having rightly stated the composition of sul-
phuric acid.

I again assert that neither Thomson, Henry, nor Brande, men-
tions the existence of oxygen or nitricum in ammonia. It is not
necessary to quote at length : Dr. Thomson (System, vol. i. p.
225) says, it is " a compound of three atoms of hydrogen and
one atom of azote." Dr. Henry (Elements, vol. i. p. 401) also

1824.] upon the preceding Answer. 129

represents it as " constituted of three atoms of hydrogen = 3 + 1
atom of nitrogen = 14 ;" and Mr. Brande, of " 13 of nitrogen and
3 of hydrogen." (Manual, vol. i. p. 364.) That Goulard's extract of
lead is a sub-binacetate and not a subtritacetate is an assertion
which I again repeat. You will observe that three authors out
of four whom you quote in support of your opinion, infer the
composition of this acetate of lead, not from analysis, but from
an experiment of Berzelius ; the fourth authority, Mr. A. T.
Thomson, is so far from asserting this compound to be a subtrit-
acetate, that he quotes the very analysis upon which I founded
my conclusion of its nature. Mr. Thomson says (London Dis-
pensatory, p. 693), "According to the experiments of Dr. Bos-
tock, the constituents of ] 00 parts of the saturated solution are
23*1 of oxide, 5 acetic acid, and 71*9 of water, which," he adds,
" agree with the statement of Thenard, who found that the salt,
when crystallized, consists of 17 parts of acid, 78 of oxide of
lead, and 5 of water, in 100 parts." Now it will appear, that
the quantities of acid and oxide by Dr. B.'s analysis, are to each
other in the proportion of 50 acid and 231 oxide; and in The-
nard's analysis as 50 to 230, very nearly. According to Dr.
Thomson, Dr. Henry, and Mr. Brande, acetate of lead is com-
posed of 50 acid +112 oxide ; and you will, perhaps, admit that,
supposing Goulard's extract to be a sub-binacetate, it must consist
of 50 acid + 224 oxide ; but if a subtritacetate of 50 acid + 336
oxide; the question, therefore, depends upon whether 231 or
336 are nearer to 224, and I think I may safely leave it to you to
decide.

I must again insist that at p. 81 of your Elements, no rules are
given for describing those salts that contain an excess of base.
The 14 lines to which you allude have not slipped out of my
copy ; but if these 14 lines ever contained a syllable respecting
sub-bisalts or sub-trisalts, such syllable has indeed disappeared.
In p. 94, to which you refer me for a continuation of the subject,
all that is contained respecting it is, that to express the number
of charges, the terms employed are, " subsesquiphosphate, sub-
bisulphate, for salts with excess of base." Not a word occurs
respecting subtrisalts, those which occasioned the remark that I
made. I admit that in p. 151 of the Elements of Pharmacy,
there is a paragraph which treats of the metallization of white
arsenic by the addition of " astibcarbonateofpotasse and charcoal
dust ;" but I deny that it has any connexion whatever with the
subject of detecting arsenic. It is stated without reference to
it, and just as you would mention the reduction of any other
oxide : indeed totally imperfect as the method which you had
previously stated is, it is given without any reservation, and as
possessing such a degree of certainty as would render all addi-
tional proceedings useless.

When I asserted that you had not noticed the decomposition
of water, and the formation of phosphorous acid, which occur

Neiv Series, vol. vii. k

130 Remarks on the preceding Answer. [Feb.

during the action of moist iodine upon phosphorus, I alluded
merely to your verbal statements ; and I will readily confess to
you that I did not understand a chemical theorem expressed in
such symbols as you employ.

In the first place, in giving your symbolic statement of Berze-
lius's theory, you represent his superoxidum iodicum by I 3 , but

he by I ; your symbol means 3 atoms of iodicum, not iodicum

combined with 3 atoms of oxygen ; P is Berzelius's representa-
tive of phosphorous acid, consisting of phosphorus + 3 atoms of
oxygen; your symbol of P 1 , if it have any meaning, is that of

1 atom of phosphorus. Again, you represent the " iodic acid
ofBerzelius" by P, which, according to him, means 2 atoms of

iodicum ; his symbol is I.

I observe also, that you suppose the phosphorous acid ofBer-
zelius to contain only 1 atom of oxygen, whereas he states it to
contain 3 atoms. On this subject 1 may remark, that you have
performed a feat on paper which Berzelius himself would be glad
to see reduced to experiment ; if you find that his phosphorous
acid is formed without the decomposition of the water, you
are of course able to present him with his imaginary iodicum in
an isolated state ; for it must have surrendered its 3 atoms of
oxygen to the phosphorus.

The hydriodic acid of Gay-Lussac, which you allow to be
formed in this experiment, is not the iodic acid of Berzelius ; he

terms it iodas hydricus,* and represents it by Aq I, and not

by I, as he would do if it were mere iodic acid, and still less by
I 9 , as you have done, which, as I have already observed, means

2 atoms of iodicum.

In explaining Gay-Lussac's theory, you have employed H 1 to
express an atom of water ; whereas in your "right " statement of
the composition of sulphuric acid, you employ the word at full
length, thus; " S 1 -f water;" Berzelius, however, adopts Aq,
and if H' have any meaning at all, it designates one atom of
hydrogen. In order to represent the oxygen of the atom of
water, you separate the coefficient thus, J- ; while Berzelius
represents it by O, and 2 atoms of oxygen by O', but -i- s would
be rather an odd expression for the same meaning.

I have now done with your symbols, and nearly with my
remarks. If the errors you have committed have produced any
effect upon me, it is that of confirming my utter dislike of symbolic
notation. When explaining the motives that induced you to adopt
an arrangement which to me appeared of a most extraordinary
description, you have attributed to it the advantage of train-
ing the student to scepticism or indifference in theoretical points ;

* Essai sur la Theorie des Proportions Chimiques, Table, p. I IS. ■

1824.] Dr. Traill on the Detection of Arsenic. 131

and you almost congratulate yourself upon the errors committed
with respect to sulphuric acid, as better adapted for your pur-
pose than the truth would have been ; what happy advantage
you may discover in the utter confusion in which you have in-
volved the Berzelian symbols, I cannot imagine ; and although
your student may, in the commencement of his career, acquire
scepticism or iudifforence in theoretical points, he must, I think,
terminate it in the belief that you do not possess " that cautious
habit of distinction " which it is your boast to have attained.

Yours, &.c. R. Phillips.

Article XV.

Ou the Detection of small Quantities of Arsenic.
By T. S. Traill, MB. &c.

(To the Editor of the Annals of Philosophy.)

DEAR SIR, Liverpool Royal Institution, Jan. 16, 1824.

Youu very interesting paper in the last number of the Annals,
on the tests of arsenic, followed by an application to examine the
contents of a stomach in which I discovered that deleterious
substance, has drawn my thoughts to a subject which has often
engaged my attention, from having been repeatedly called on to
determine the nature of substances found in the alimentary canal
of persons who have died under suspicious circumstances.

Your remarks on the application of the usual liquid tests are
extremely just, and, in my opinion, leave nothing further to be
desired on the subject ; but 1 have long been aware of the erro-
neous opinion entertained by authors of reputation, respecting
the inutility of attempting to reduce to the metallic state, portions
of white arsenic considerably less than a grain. Even by the
common process, 1 have often succeeded in reducing to a per-
fect metallic film much less than half a grain of the arsenious
acid ; although it was the opinion of the celebrated Black, that
one grain", and of Dr. Bostock that three-quarters of a grain, are
the smallest quantities from which we can hope distinct results
by this process. 1 may here notice the importance of attempt-
ing the reduction in all cases of suspected poison; for it has
several times happened, that I have been able to show the pre-
sence of arsenic in cases where it has been supposed absent,
because the white powder gave no alliaceous smell when thrown
on a live coal. This method of operating should be abandoned ;
because the carbonic acid and sulphureous vapour from the coal
disguise the peculiar odour of the arsenic; and much of the
powder is probably raised in vapour without reduction, and con-
sequently without giving out the alliaceous smell.

k2

132 Dr. Traitt on the Detection of Arsenic. [Feb.

The trouble and delay of preparing a coated tube induced me
long ago to attempt the reduction in a thin glass tube, with the
naked fire, or with the blowpipe ; and the facility thus obtained
made the reduction much less irksome. But your happy sug-
gestion of the spirit-lamp has rendered the process still more
easy — even elegant ; and has euabled me to produce unequivocal
metallization of arsenic from portions of the white powder far
more minute than what has been mentioned — a circumstance of
no small moment, as it affords the most unexceptionable test of
what may affect the life of a human being.

The following simple apparatus is all that is requisite ; and
after many trials, I give the process about to be described the
preference.

Take a thin glass tube 2i inches long, and about 0*4 inch
wide, closed at one end, with a slightly dilated mouth ; like the
common test tubes of the blowpipe apparatus. A piece of cop-
per wire, loosely twisted round its upper end, serves to attach it
to any convenient support, at an angle of about 30° or 40° ; while
the flame of a spirit-lamp is applied to the closed end of the tube
containing the mixture to be reduced.

I employ either the black flux, or a little subcarbonate of soda
or potash mixed with charcoal powder. Either of these should
be at least equal to thrice the weight of the substance to be
ascertained ; but a small excess of them is safer than the oppo-
site extreme. Where the quantity is not very minute, it is
unnecessary to grind the whole ingredients together, but mixing
them on a piece of glass, or of writing paper, with the point of a
knife, before they are introduced into the tube, will be sufficient.
The tube should be dry and clean ; and its orifice may be
slightly stopped with paper. Where the quantities are very
minute, 1 usually grind them in an agate mortar; but as every
such manual operation, however simple, is embarrassing to those
little habituated to experiment, I consider it very useful to sim-
plify the whole process by omitting this operation, and substitut-
ing an addition of charcoal powder, after the mixture is intro-
duced into the tube. The flame of a spirit-lamp will speedily
raise the closed end of the tube to a dull red heat ; and in less
than two minutes, a shining metallic crust will invest the upper
side of the inclined tube, about half an inch from the flame.
When the tube is cold, 1 shake out the loose materials from
the bottom, and then scrape off the metallic crust from its sides
with a knife. This saves the tube for further use, a matter of
some consequence in the country. By this process I have
reduced less than one-eighth, and even than one-tenth of a grain
of arsenious acid, or, as it is sometimes called, the white oxide,
to the metallic state. The metallic crust afforded by one-tenth
of a grain, was perfectly distinct to the naked eye, and very con-
spicuous when a lens was employed. The scrapings of the tube
in this case glistened strongly, with a metallic lustre, on the

1824.] Mr. Biggs on the Expansion of Gases. 133

clean blade of the knife ; and when six different portions of this
substance were projected on a poker, heated to a dull red, each
gave a distinctly visible white smoke, and decided alliaceous
odour; although each portion could only have contained about
l-78th of a grain of the metal.

I may add, that if a clean knife be held in the fumes, a portion
of a white powder will be condensed on the blade, even from the
most minute portions of arsenic which I have thus volatilized.
I am, dear Sir, very truly yours,

Thomas Stewart Traill.

Article XVI.

On the Expansion of Gases. By Mr. Matthew Bi°-o- s .
(To the Editor of the Annals of Philosophy.)

DEAR SIR, j an . | 5 , 1824.

A gentleman signing himself X. has, in the Philosophical
Magazine for December, given some algebraic formula? for cal-
culating the expansion of gaseous fluids under increasing tem-
perature, which, he says, prove the accuracy of certain rules for
the same purpose, which I referred to in a paper you were o- od
enough to insert for me in the Annals of Philosophy for Decem-
ber, and the inaccuracy of some which I proposed to substitute
for them. It is so evident that he is wrong, that I had not
intended to take any notice of what he says, but having been
told that some answer ought to be made, I may just observe, that
any person who will take the trouble of working the same sum
by his method, at one operation and at several, may satisfy him-
self that no dependance whatever is to be placed upon it ; thus,
let 100 volumes of gas at 32° be raised to 212°,

100(480 + 180) 10 „ ,

— So =137-5,

This is correct according to Gay-Lussac and others.

Now let 100 volumes of gas at 32° be raised to 212° by four
several additions of 45°,

,00(480 + 45 l = 109-375,

480
109-375(480 + 45)

4s0
119-6289(480 + 45)

= 119-6289,

= 130-8441,
= 143-1107,

480
1.10 8441 (480 4 45)

upwards of 5| volumes more than the truth ; and if the elevation

134 Mr. Levy on a neto Mineral Substance [Feb.

of temperature be supposed to take place by additions of sing le
degrees, it is clear that the error must be immense.

The gentleman is pleased to observe at the close of his paper,
that he has shown the failure of my attempt to correct the rules
which have been given for making the above calculation, and
that the one which I have proposed is not perfectly accurate.
How he has proved this, I am at a loss to discover ; but I ima-
gine that whether my results are accurate or not, his will form
no standard by which to judge of them.

I am, Sir, yours respectfully,

Matthew Biggs.

Article XVII.

Account of a new Mineral Substance. By M. Levy, Esq. MA.
in the University of Paris.

(To the Editor of the Annals of Philosophy.)

DEAR SIR, Jan.20, 1824.

At the suggestion of Mr. Heuland, I propose to give the name
of Bucklandite (in honour of the celebrated Professor of Oxford),
to a mineral substance, the crystallographical characters of
which I find to differ from any hitherto described.

I have observed this new mineral upon a specimen belonging
to Mr. Turner's collection ; it was placed with the pyroxenes, to
which substance it has a great resemblance of form and external

Fig. l.

Fig.

Fig. 3.

V *,-

7

VI

,v -

^

/

a '-3

characters. It occurs in small crystals represented by figs. 2
and 3 ; their colour is brown, nearly black, and they are opaque.
They easily scratch glass, and appear to me to be much harder
than pyroxene. I could not find any cleavage parallel to the
natural planes of the crystals, nor in any other direction. The

1824.] Mr. Levy on a new Mineral Substance. 135

specific gravity and analysis I cannot give without spoiling the
specimen, because a sufficient quantity of the substance could
not be detached for the purpose of experiment.

From figs. 2 and 3, it is obvious that the forms of the crystals
which they represent may be derived from an oblique rhombic
prism, and that by assuming the faces I have marked m as the
lateral planes of the primitive, and that marked P as the base,
all the others will be the result of simple laws of decrements. An
oblique rhombic prism may, therefore, be assumed as the primi-
tive form of this substance; but to the same class of prisms
belongs also the primitive form of pyroxene ; it remains, there-
fore, to examine whether those two primitive forms are connected
by any simple mode of derivation ; and first, in order to give
greater weight to the result of this investigation, it is necessary to
mention that although most of the crystals have their faces covered
with a greyish earthy substance, which render them unfit to be
measured by the reflecting goniometer, it is, however, possible
to measure some of the incidences by that means, by rubbing off
previously the earthy matter which covers the planes.

If the crystal represented by fig. 2, is derived from the primi-
tive of pyroxene, the faces marked p and A 1 must be either the
results of decrements upon the angles a and o of the primitive,
or the one being the result of such a decrement, the other must
be the base of the primitive, or the face which replaces the edge
h, and is the result of a decrement by one row upon that edge.
Now let n be the law of decrements, which would produce upon
the angle a of the primitive of pyroxene a face corresponding to
one of the two faces p and h\ fig. 2, and n x the law which would
produce the other upon the angle o, let h be the lateral edge of
the primitive of pyroxene 1, being the oblique diagonal of the
base. Let a represent the angle of the base of the primitive of
pyroxene with the edge h, and let /3 equal the angle of the two
facesp and h\ fig. 2 ; that is to say, equal to (a n , o"'). Then the
following formula will easily be found :

rp , , „, , „ h sin. a(n + n 1 )

Tang, (a", o nl ) = tang. |S = -

+ (n — n 1 ) cos. « — 1

Now, if in this formula the numerical values of h, a, /3, corre-
sponding to the particular case we are considering, are substi-
tuted, it will be found that no simple values of n and n l can
satisfy the equation, nor could any simple value be obtained for
the one if the other was supposed to be equal to nothing, or
infinity ; that is to say, if one of the faces p or h\ fig. 2, was
supposed to be parallel to the edge h of the primitive of pyrox-
ene, or to the base of the same form. It appears, therefore, that
this substance does not belong to pyroxene ; the only other mi-
neral to which it bears some analogy is amphibole, but this last
substance cleaves always very easily parallel to the lateral planes
of the primitive, and besides it might be proved that their forms
are incompatible in the same way as it has been done for pyroxene.

136 Corrections in Right Ascension of [Feb.

From the measurements I have taken, which very nearly agree
with those Mr. W. Phillips was so kind as to take upon a small
crystal I gave him of this substance, I am led to take for the pri-
mitive form, an oblique rhombic prism in which the two lateral
planes are inclined to each other at an angle of 70° 40', the base
upon either of the lateral planes at an angle of 103°56 / , and in
which the ratio of one side of the base to the lateral edge is
nearly 100 to 97.

The other incidences are,

(m,fc) = 125° 20) (p, c") = 121° 30' (p, ft 3 ) = 95° 40'
(p, A 1 ) = 114° 55) (p, a*) = 99° 41' (m, b 5 ) = 160° 24'

These crystals are accompanied by large green opaque crystals
of scapolite, lamellary black hornblend, and flesh-coloured lami-
nary carbonate of lime. The specimen comes from the mine
Neskiel, near Arendal, in Norway.

Article XVIII.

Corrections in Right Ascension of 37 Stars of the Greenwich
Catalogue, together with an Inquiry hoic far it would he advi-
sable that the Daily Corrections in R.A. and North Polar Dist-
ance of the 46 Zero Stai-s should be computed Annually at the
Public Expence. By James South, FRS.

(Concluded from p. 45.)

Having in the former part of this paper asserted, that the
corrections in right ascension of the principal fixed stars, can-
not be obtained piece-meal without considerable trouble, and
occasional error, we will now see how far the procuring correc-
tions in polar distance, is subject to similar inconveniences ; in
doing this, we will accompany the practical astronomer, first
into the observatory, secondly into the computing room.

The instrument commonly employed for determining polar
distances, is a telescope attached firmly to a graduated circle,
and by means of micrometer microscopes placed opposite various
parts of its divided limb, the errors of eccentricity, division, and
partial expansion, are either destroyed, or rendered almost insen-
sible. The observations are generally conducted in the meri-
dian, and are extremely simple, consisting only in the accurate
bisection of the star, by the horizontal wire, situate in the focus
of the object glass ; this done, the different microscopes are read
off, and the mean gives the observed polar distance of the
star.

To this, however, corrections must be applied ; generally for

1824.] Thirty-Seven Principal Stars. 137

refraction, and always for aberration, lunar nutation, solar nuta-
tion, and variation, ere the index error of the instrument can be
found, by a single zero star ; and in proportion as many, or few
of these stars are observed, will the index error be well, or ill
determined ; and the importance of its being accurately ascer-
tained cannot, perhaps, be rendered more evident than by stat-
ing, that index error is to observations with the circle, what the
clock's error is, to observations with the transit instrument. But
lest I should be suspected of exaggerating the difficulties of pro-
curing, either the corrections in right ascension, or those of
polar distance, I will here present the reader with a specimen of
each.

Greenwich Observations for 1821, Nov. 27.

a Lyrse.

Observed right ascension 18 h 30' 46*33"

Observed polar distance 51° 21' 33*9"

Barometer 29-54 inches.

Thermometer 46°

Correct ion for Right Ascension.

Equation for aberration, precession, and solar inequality of
precession.

By Maskelyne's Table 17, column « Lyras, Nov. 26 = -f-0-38"

Dec. 6 = + 0-30

Therefore diff. for 10 days = -O08"

And diff. for 1 day = -0-008

The equation, therefore, for Nov. 27 will be + 0-38" — 0-008"
= + 0-372".

Equation for Nutation.

By reference to the Nautical Almanac, and by the help of a
little calculation, the place of the moon's node on Nov. 27, is
10' 29 d 35'.

By Maskelyne's Table 18, column a Lyra; 10 s 20 d = +0-41"

11 = +0-30

Therefore diff. for 10 degrees . . . . = —0-11"

And diff. for 25 minutes = —0-005

Now - 0-11" - 0-005" = - 0-105".

Equation, therefore, for 10 s 9 d 35' = + 0-41" - 0-105" =
+ 0-305" ; and + 0-372" + 0-305" = + 0-677" = the cor-
rection required.

138 Corrections in Right Ascension of [Feb.

Mean RA of a Lyra Jan. 1821 = 18 h 30' 52-92"

Correction for Nov. 27 = + 0-68

Apparent right ascension =18 30 53-60

Observed right ascension =18 30 46-33

Clock's error = - 7-27

Correction for North Polar Distance.
Equation for refraction.

Greenwich observ. 1812, p. 251, log. mean refraction. = 1-1 1261
1811, p. VI. + log. of bar. 29-54,
and therm. 46° = 000347

Log. of true refraction = 1-11608

True refraction = 13 - 05".

Equation for Aberration.

Sun's longitude by Nautical Almanac for Nov. 27 a* 8 s 4° 58'
Gr. obs. 1813, p. 260, column a Lyra to be added 6

Sun's long, at the time of the transit of a Lyra. = 8 5 4
Annual number for aberration obs. 1812, p. 251 =6 5 26

Diff. taken so that it may be less than 6 signs . . = 1 29 38

Log. cosine = 9-7037

Gr. obs. 1812, p. 251 + log. max. of aberration. = 1-2523

Los:, of aberration = 0-9560

Aberration = — 9-04". The sign is negative, because the
difference between the sun's longitude and the annual number for
aberration is less than 3 signs. This sign is to be applied to
reduce the mean N. P. D. to the apparent.

Equation for Lunar Nutation.

Right ascension of a Lyra in space = 9 s 7° 44'

Longitude of the moon's node = 10 29 35

Right ascension — long, moon's node = 10 8 9

Right ascension + long, moon's node = 8 7 19

Greenw. obs. /8-34 // sin. (AR - long. ) s node) = — 6-56"
1812, p. 340. "t 1-20 sin. (AR + long, y node) = - 1-10

Lunar nutation = — 7-66". This sign is to be applied to
reduce the apparent to the mean N. P. D.

Equation for Solar Nutation.

Gr. obs. 1813, p. 260, col. a Lyra equation for Nov. 26= -0-22"

Dec. 6= -0-37

/

1824.] Thirty-Seven Principal Stars. 139

Hence diff. for 10 days = + (Ho"

And diff. for 1 day = + 0-015

The equation, therefore, for Nov. 27 = — 0-235'". The sign
is to reduce mean to apparent N. P. D.

Equation for Variation.

Gr. obs. 1813, p. 260, equation for Nov. 26 = +2-71

Dec. 6 = + 2-78

Hence diff. for 10 days = + 0-07"

And diff. for 1 day = 0-007

The equation, therefore, for Nov. 27 = + 2-717". This sign
is to reduce the observed N. P. D. to the mean.

Hence the correction for N. P. D. is + 13.05" + 9-04"
- 7-66" + 0-235" + 2-717" = + 17-382".

Observed N. P. D = 51°

21' 33-9"
+ 17-382

Apparent N.P.D = 51

Mean N. P. D. Jan. 1 = 51

21 51-282

22 37-2

- 45-918

On inspecting these calculations, remembering that they alone
refer to observations of a single star on a particular day, and
aware that similar are needed for every zero star, as often as it is
observed, few I apprehend will be found to dispute the point,
that corrections in right ascension, and north polar distance,
cannot be procured at the time ofivantingthem, without frequent
error, and disgusting labour.

Proceed we now to investigate the nature, and extent of the
advantages, which would result, were we but supplied annually
with a publication containing the daily corrections of the 46 zero
stars. These would be comprised, in the equality upon which
it would place the British, with the foreign observer — in the
inducements which it would hold out, to the study of practical
astronomy — in the comparative ease with which it would enable
astronomers employed on scientific missions, to obtain accurate
astronomical observations — in the facilities which it would afford
us in the examination of published observations — in the superior
accuracy with which our most important observations would be
reduced; and lastly, in the immense labour which would be
saved. We will consider them in order.

1 . As to the equality to which it would raise the British with the
foreign observer. — On the continent by the industry of a Danish
astronomer, and by the aid of the Danish government, the appa-
rent places of the 46 zero stars for every tenth day of the year, have
been published annually some time past ; but as the mean places

140 Corrections in Right Ascension of [Feb.

employed at our Royal Observatory, are not therein used ; and
as the corrections themselves do not exactly accord with those
obtained from Maskelyne's, or Pond's tables, the work to us is
rendered comparatively of little value; added to this also, it has
never found its way into this country, till many months of its
year have elapsed. When, however, it has arrived, I believe it
has been empluyed by some, on the principle that any assistance
was better than none. But let it come as it may, sooner or
later, it ill accords with the general scientific spirit of the British
government, to allow its astronomers to feel indebted for any
standard tables, to the labour of any j'oreign individual, or to the
generosity of any nation upon earth.

As to the inducements which it would hold out to the study
of practical astronomy ; — that practical astronomy labours under
more disadvantages, than any other pursuit, few I believe will
deny ; the expence of procuring instruments, the trouble in
using them, the uncertainty through capricious weather, of being
able to use them when we wish j the time (namely the night)
when alone they can be employed to the greatest advantage ; the
sacrifices of the amusements, either of fancy, or of fashion,
which a close attention to their use naturally entails upon us ;
the recollection, that while the labourers in other departments
of science are frequently rewarded by some brilliant discovery,
we " cast our bread upon the waters, expecting not to see it for
many days," are powerful preventives to the general cultivation
of practical astronomy ; but when in addition to these, it is felt,
that the pleasures of observing are only preparatory to the
labours of computing ; known that more observations can be
procured in one night, than can be reduced during the succeed-
ing day ; remembered that unreduced observations are of no use ;*
then I say it is astonishing, not that we have so few, but that we
have any private observers at all ; and well do I know, that many
good instruments are now lying idle, which if the auxiliary
alluded to were afforded, would be immediately employed. But,
perhaps, some will say, private observers are unworthy of consi-
deration.f If any such there be, I would remind them, that a
private observer at Wanstead, discovered the aberration of light;
and but for the labours of a private observer at Westbury, the
Greenwich mural quadrant would probably, at the present
moment, be distributing its inaccuracies to the astronomers of
Europe, and the world.

• Instances have occurred in which such a mass of unreduced observations has accu-
mulated, that the observer has been induced to abandon further observations; knowing
that he had by him already, more than he could expect to reduce during his life ; and
on a recent occasion, a distinguished astronomer was, under such a feeling, impelled to
part with his instrument. Thus has practical astronomy lost one of its most indus-
trious cultivators in the retirement of Mr. Groombridge. It will, however, be some
satisfaction to know, that his observations, from 20,000 to 30,000 in number, are at the
present time being reduced at the public expence !

•}• That Government think differently, is obvious from the preceding note.

1824.] Thirty-Seven Principal Stars. 141

As to the comparative ease with which it would enable astro-
nomers employed on scientific missions, to obtain accurate
astronomical observations ; — greatly to the credit of the British
government, it has of late years transmitted to distant parts of
the globe, several distinguished men, for various scientific pur-
poses ; the period which from some cause or other, they can
remain at the same station being generally short, any thing
which would enable them to multiply observations, or to confer
accuracy on those made, would prove highly valuable. At home,
surrounded by all the paraphernalia for reducing observations,
we have shown that the drudgery is hardly tolerable ; how much
more severely then must it be felt by the travelling astronomer,
whose situation denies him these advantages : his observations
are purely differential, having the Greenwich stars as points of
departure : grant him, therefore, the daily corrections of them,
and his labours, instead of being protracted, would terminate,
almost as soon, as the observations are completed.

As to the facilities which it would afford to the examination
of published observations ; — on this head I would dilate a little ;
and much as I respect the Greenwich observations, I would with
becoming deference suggest, that some alterations be made in
the printed copies ; whereby the invaluable data which they
furnish, may more readily be converted to immediate use. For
the right ascension observations, I would propose the insertion
of a column immediately after that which contains the mean
transit, in which should be presented the clock's error by each
observed zero star; so would the position of the instrument, with
regard to the meridian, be instantly seen, although superior and
inferior transits, of the same circumpolar stars, through unpro-
pitious weather, may not have been procured. Were also the
clock's daily rate computed from consecutive clock's errors, by
the same stars in lieu of consecutive transits of the same stars,
increased accuracy would be the result. For the observations
of polar distance, two additional columns would be desirable;
one appropriated to the correction for barometer and thermome-
ter, the other wherein the index error, as found by each star,
might be entered in the same manner as was hinted at for the
clock's error; and at the end of each day's work, the mean
index error should be inserted, so that a person, wanting the
polar distance of any comet, or planet, might easily arrive at it
by applying to its observed place corrected for refraction, the
necessary equation for index error. If also the apparent diame-
ter of the planet, as observed with the micrometer were sub-
joined, it would, I think, be an improvement. Observations
thus published woidd, with the assistance of the daily corrections,
be readily examined, and occasional errors, however trivial,
would promptly be discovered ; but without such an arrange-
ment, or such an aid, the labour of wading through a mass of
observations of zero stars alone, is such that few individuals

142 Corrections in Right Ascension. [Feb.

would think of undertaking it. I have dwelt upon this subject,
from an opinion (perhaps a foolish one) I entertain, that much of
the differences between Dr. Brinkley's and Mr. Pond's cata-
logues, may originate not in the observations themselves, but in
the manner in which those observations may be reduced.

As to the superior accuracy with which our most important
observations would be reduced ; — corrections computed at the time
must alway be liable to error ; but if taken from tables, the accu-
racy of which is well established, this source of mischief must be
excluded.

Lastly, as to the labour which the published corrections
would save ; — this, perhaps, it would be difficult precisely to
ascertain. In a former part of this paper, it has been said, that
three minutes would be required for obtaining the corrections of
a single star, in right ascension only; and I think those of north
polar distance cannot be procured in less than twelve; so that
fifteen minutes will be spent in getting both corrections. Now
it is not too much to say, that 20 zero stars may be observed
daily, in good observing weather ; and supposing 90 such days
to occur in the year, 450 hours will be consumed in obtaining
corrections, which were they published annually, might be
appropriated to some useful purpose. This, however, would be
the labour saved at one observatory only, say at Greenwich ; but
there are other observatories, where as well as at Greenwich, the
advantages would be felt ; some dependent upon Government ;
some belonging to public bodies ; and others, the property of
private individuals ; that we may form something like an esti-
mate, of the aggregate benefit, let us enumerate the principal
ones. Connected with Government, we have the observatories
at the Cape, at Kevv, at Portsmouth, and at Bagshot. Belong-
ing to public bodies, we have the observatories at Madras, at
Dublin, and at Oxford. As property of private individuals, the
observatories of Col. Beaufoy, and Sir Thomas Brisbane; of the
Rev. Mr. Catton, and Mr. Cooper ; of the Rev. Mr. Evans, and
Major Kater; of the Rev. Dr. Pearson and Mr. Sheepshanks.
He, therefore, who can doubt that an immensity of labour would
be saved by published corrections may be supposed able to
doubt almost his own existence.

Now as to the expence of procuring the publication in ques-
tion. At present the apparent places* of 34 of the Greenwich
stars for eveiy 10th day of the year, are published by the Board of
Longitude ; so that the corrections for only 20,f remain to be pur-
chased. What the. Commissioners may pay for those of the 24, 1
know not; but I well know that daily corrections in right ascen-
sion and north polar distance of the 46 stars for one year may be

* The corrections are preferable to the apparent places, as they enable the observer
to use the mean places from the latest determinations.

■f The two stars of a Librae, and the two of a Capricorni, require only that the cor-
rections for one itar of each should be computed.

1824.] Analyses of Books. 143

calculated by one computer for forty pounds : it is not likely,
therefore, to be far from correct, if we say that for forty pounds
more than are at present expended, the daily corrections might
be procured, done by two separate computers, and consequently
entitled to every possible confidence.

Having shown what would be the benefits which would result
from such a publication ; having pretty well ascertained what
would be the expence of procuring it ; it only remains to see,
how far the former are equivalent to the latter : — the task is easy.
To place the British observer on an equal footing with the
foreign, is worth something; — to induce individuals to the study
of practical astronomy, is surely worth something; — to enable
travelling astronomers to multiply observations, and to prove the
accuracy of those they make, is certainly worth something ; — to
afford facilities to the examination of published observations, is
doubtless worth something; — to entail accuracy in the reduction of
the most important observations, is unquestionably worth some-
thing; — and to save an immensity of labour is indisputably worth
something. What may be the individual value of the advantages
just enumerated, it is needless to inquire ; but taken collectively,
I hesitate not to say, that it is equivalent at least to ten times the
sum which need be spent in procuring it.

Hence I can come to the conclusion, " That the daily correc-
tions in right ascension and north polar distance of the 46 zero
stars, should be published annually at the public expence."

Bkckman.strcct, Jan. 29, 1824. JAMES SOUTH.

Article XIX.
Analyses of Books.

Philosophical Transactions of the Royal Society of London, for

1823. Part II.

(Continued from p. 63.)

XVI. An Account of an Apparatus on a peculiar Construction
for performing Electromagnetic Experiments. By W. H. Pepys,
Esq. FRS.— (See Annals, N. S. v. 392.)

XVII. On the Condensation of several Gases into Liquids. By
M. Faraday, Chemical Assistant in the Royal Institution.
Communicated by Sir H.Davy. (See the present number, p. 89.)

XVIII. On the Application of Liquids funned bu the Conden-
sation of Gases as mechanical Agents. By Sir Humphry Davy,
Bart. Pres. RS.

" The elasticity of vapours in contact with the liquids from
which they are produced under high pressures by high tempera-
tures, such as those of alcohol and water," observes the Presi-

144 Analyses of Books. [Feb.

dent, after some prefatory remarks, " is known to increase in a
much higher ratio than the arithmetical one of the temperature ;
but the exact law is not yet, determined ; and the result is
a complicated one, and depends upon circumstances which
require to be ascertained by experiment. Thus the ratio of the
elastic force, dependent upon pressure, is to be combined with
that of the expansive force dependent upon temperature ; and
the greater loss of radiant heat at high temperatures, and the
developement of latent heat in compression, and the necessity
for its reabsorption in expansion (as the rationale of the subject
is at present understood) must awaken some doubts as to the
economical results to be obtained by employing the steam of
water under very great pressures, and at very elevated temper-
atures.

" No such doubts, however, can arise with respect to the use
of such liquids, as require for their existence even a compression
equal to that of the weight of 30 or 40 atmospheres : and where
common temperatures, or slight elevations of them, are sufficient
to produce an immense elastic force ; and when the principal
question to be discussed is whether the effect of mechanical
motion is to be most easily produced by an increase or diminu-
tion of heat by artificial means.

" With the assistance of Mr. Faraday I have made some
experiments on this subject, and the results have answered my
most sanguine expectations. Sulphuretted hydrogen, which
condenses readily at 3° Fahr. under a pressure equal to that
which balances the elastic force of an atmosphere compressed
to T ' T , had its elastic force increased so as to equal that of an
atmosphere compressed to T ' T by an increase of 47° of temper-
ature. Liquid muriatic acid at 3° exerted an elastic force equi-
valent to that of an atmosphere compressed to -^ ; by an
increase of 22°, it gained an elastic force equivalent to that of
an atmosphere compressed to ? ' T ; and by a further addition
of 26°, an elastic force equivalent to that of air condensed to
■^t, of its primitive volume. These experiments were made in
thick glass tubes hermetically sealed. The degree of pressure
was estimated by the change of volume of air confined by mer-
cury in a small graduated gage, and placed in a part of the tube
exposed to the atmosphere, and the temperatures were dimi-
nished from the degree at which the gage was introduced, i. e.
the atmospheric temperature by freezing mixtures ; so that the
temperature of the air within the gage could not be considerably
altered ; and as the elastic fluid surrounding the gage must have
had a higher temperature than the condensed fluid, the diminu-
tion of the elastic force of the vapour from the fluids cannot be
considered as overrated.

" From the immense differences between the increase of elastic
force in gases under high and low pressures, by similar incre-

1824.] Philosophical Transactions for 1823, Part II. 145

ments of temperature, there can be no doubt that the denser the
vapour, or the more difficult of condensation the gas, the greater
will be its power under changes of temperature as a mechanical
agent: thus carbonic acid will be much more powerful than
muriatic acid. In the only experiment which has been tried
upon it, its force was found to be nearly equal to that of air
compressed to -}-$ at 12° F. and of air compressed to -^ at
32°, making an increase equal to the weight of 13 atmospheres
by an increase of 20 of temperature ; and this immense elastic
force of 36 atmospheres being exerted at the freezing point of
water.*

" In applying the condensed gases as mechanical agents there
will be some difficulty ; the materials of the apparatus must be
at least as strong and as perfectly joined as those used by Mr.
Perkins in his high pressure steam engine : but the small differ-
ences of temperature required to produce an elastic force equal
to the pressure of many atmospheres, will render the risk of
explosion extremely small ; and if future experiments should
realise the views here developed, the mere difference of temper-
ature between sunshine and shade, and air and water, or the
effects of evaporation from a moist surface, will be sufficient to
produce results, which have hitherto been obtained only by a
great expenditure of fuel.

" I shall conclude this communication by a few general ob-
servations arising out of this inquiry.

" There is a simple mode of liquifying the gases, which at
first view appears paradoxical, namely, b\j the application of heat ;
it consists in placing them in one lea; of a bent sealed tube con-
fined by mercury, and applying heat to ether, or alcohol, or
water, in the other end. In this manner, by the pressure of the
vapour of ether I have liquified prussic gas and sulphurous acid
gas, the only two on which I have made experiments; and these
gases in being reproduced occasioned cold.

" There can be little doubt that these general facts of the
condensation of the gases will have many practical applications.
They offer easy methods of impregnating liquids with carbonic
acid and other gases, without the necessity of common mecha-
nical pressure.

" They afford means of producing great diminutions of tem-
perature, by the rapidity with which large quantities of liquids
may be rendered aeriform ; and as compression occasions similar
effects to cold, in preventing the formation of elastic substances,

• " Since this paper was read, Mr. Faraday has ascertained that the vapour of am-
monia at 32° everts an elastic force equal to that of an atmosphere compressed to

1 . 10

— ; and at 50° to that of an atmosphere compressed to — : and that the vapour of ni-

trous oxide at 32° has an elastic force equal to that of an atmosphere compressed to
tj-; and at 45° to an atmosphere compressed to — - nearly."

New Series, VOL. VI I. k

146 Analyses of Books. [Feb.

there is great reason to believe that it may be successfully-
employed for the preservation of animal and vegetable substances
for the purposes of food."

An appendix to this paper gives the following statement : —

** In investigating the laws of the elastic forces exerted by
vapours or gases raised from liquids by increase of temperature
under compression, one of the most important circumstances to
be considered is the rate of the expansion, or what is equiva-
lent, of the elastic force, in atmospheres in different states of
density.

" It has been shown by the experiments of MM. Dalton and
Gay-Lussac, that elastic fluids of very different specific gravities
expand equally by equal increments of -temperature, or, as it
may be more correctly expressed, according to the elucidations
of MM. Dulong and Petit, that mercury and air, or gases, are
equivalent in their expansions for any number of degrees in the
thermometrical scale between the freezing and boiling points of
water ; and the early researches of M. Amontons seemed to show
that the increase of the spring or elastic force of air by increase
of temperature, was in the direct ratio of its density. I am not
however acquainted with any direct researches upon the changes
of volume produced in gases in very different states of conden-
sation and rarefaction by changes of temperature, and the
importance of the inquiry, in relation to the subject of my last
communication to the Society, induced me to undertake the
following experiments.

" Dry atmospherical air was included in a tube by mercury,
and its temperature raised from 32° Fahr. to 212°, and its expan-
sion accurately marked. The same volumes of air, but of double
and of more than triple the density under a pressure of 30 and
65 inches of mercury, were treated in the same manner, and in
the same tubes ; and when the necessary corrections were made
for the difference of pressure of the removed column of mercury,
it was found that the expansions were exactly the same.

" An apparatus was constructed, in which the expansions of
rare air confined by columns of mercury were examined and
compared with the expansions of equal volumes of air under
common pressure ; when it appeared, that for an equal number
of degrees of Fahrenheit's scale, and between 32° and 212° they
were precisely equal, whether the air was ^, i, or -^ of its natural
density.

" Similar experiments were made, but they were necessarily
less precise, with air condensed six and expanded fifteen times,
with similar results."

XIX. On the Temperature at considerable Depths of the Carib-
bean Sea. By Capt. Edward Sabine, FRS. : in a Letter
addressed to Sir H. Davy.— (See Annals, N. S. v. 462.)

XX. Letter from Capt. Basil Hall, RN. to Capt. Kater, com-
municating the Details of Experiments made by him and Mr.

1824.] Proceedings of Philosophical Societies. 147

Henry Foster, with an Invariable Pendulum ; in London ; at the
Galapagos Islands in the Pacific Ocean, near the Equator; at
San Blasde California on the NW Coast of Mexico ; and at Rio
de Janeiro in Brazil. With an Appendix, containing the Second
Series of Experiments in London, on the Return.

" Abstract of the most exact Results at each Station."

Stations.

[Diminution of Gravity
from Pole to Equator.

Galapagos 0°32' 0"N
San Bias.. 21 30 25 N
Rio 22 55 22 S

Ellipticity.

•0051412
•0054611
•0053431

!8 4'?8

_ 1 _
3 1 5" 5 o

1

." o e ■ .j 7

Length of Equat.
Pend.

39-017196

39-00904

39-01206

{To be continued.)

Article XX.

Proceedings of Philosophical Societies.

ROYAL SOCIETY.

Dec. 1 {continued). — When the President had concluded his
address to the Astronomer Royal, the Society proceeded to the
election of a Council and Officers ; and the following were de-
clared duly elected: —

Of the Old Council.— The Right Hon. Sir H. Davy, Bart.;
Samuel Goodenough, Lord Bishop of Carlisle ; W. T. Brande,
Esq. ; Taylor Combe, Esq. ; J. W. Croker, Esq. ; Davies
Gilbert, Esq. ; Charles Hatchett, Esq. ; Sir Everard Home,
Bart. ; John Pond, Esq. ; W. H. Wollaston, MD. ; Thomas
Young, MD. For. Sec.

Of the New Council. — Bernard Edward, Duke of Norfolk ; Sir
James Mac Gregor, Bart. ; William Allen, Esq. ; Major Thomas
Colby ; James Ivory, Esq. ; William Marsden, Esq. ; W. G.
Maton, MD.; Edward Rudge, Esq.; William Sotheby, Esq.;
Henry Warburton, Esq.

President.— The Right Hon. Sir H. Davy, Bart.

Treasurer. — Davies Gilbert, Esq.

Secretaries. — W. T. Brande, Esq. and Taylor Combe, Esq.

Dec. 11. — John Bayley, Esq. and George Townley, Esq.
were admitted Fellows of the Society; and MM. Fourier and
Vauquelin were elected Foreign Members.

A paper was communicated, " On the Nature of the Acid and
Saline Matters usually existing in the Stomachs of Animals ;" by
William Prout, MD.FRS.

The object of this paper was to prove, that the acid usually
found to exist in the stomach of animals during the digestive

l2

148 Proceedings of Philosophical Societies, [Feb.

process is the muriatic acid, and that the saline matters consist
chiefly of the alkaline muriates.

The method adopted by the author to prove this, was to digest
the contents of the stomach of a rabbit, or other animal, in dis-
tilled water as long as they imparted any thing to that fluid.
The solution was then divided into four equal portions. The
first of these was evaporated to dryness in its natural state, and
the residuum burnt, by which means the muriatic acid in union
with z. fixed alkali was ascertained. Another portion was super-
saturated with potash, evaporated to dryness, and burnt as before,
and thus the total quantity of muriatic acid present determined.
A third portion was exactly neutralized with a solution of potash
of known strength, which gave the proportion of free acid pre-
sent. A fourth portion was reserved for miscellaneous ex-
periments. From the results thus obtained, checked by others,
the author was enabled to ascertain the proportion of muriatic
acid present, whether in union with a fixed or volatile alkali,
or in an unsaturated state ; and the quantity in the latter state
was always found to be considerable, and in some instances
greater than the quantity in combination. Dr. Prout obtained
similar results in different animals, as well as in the human sub-
ject, and in one instance, from 20 ounces of fluid ejected from
the human stomach, in a severe derangement of that organ, he
found upwards of half a dram of muriatic acid of specific gravity
1-160.

The reading was also commenced of a paper, entitled, " An
Inquiry respecting the supposed Heating Effect beyond the Red
End of the Spectrum; by Baden Powell, MA. of Oriel College,
Oxford: " communicated by J. G. Children, Esq. FRS.

Dec. 18. — The reading of Mr. Powell's Inquiry was con-
cluded.

The primary object was to ascertain whether the explanation
of the invisible heating rays suggested by Prof. Leslie, viz. that
the effect was owing to a concentration of secondary light
reflected from the clouds, refracted to a position just without the
red rays, was correct or not. — (Inquiry into the Nature and Pro-
pagation of Heat, p. 457, and note 45.)

The experiment was tried with a differential thermometer, having
the sentient bulb blackened with Indian ink. The prism was
placed in situations most favourable to such an effect, and in
various inclinations ; but the effect exterior to the red rays was
never more than 3°, while in the extreme visible red, it was often
from 16° to 25°.

The effect of altering the coating was next tried; and on
covering the bulb with thin yellowish-brown silk, it stood in the
extreme red rays at 7° ; half an inch beyond, at 7° ; while, when
merely blackened, it stood in the red at 12°; half an inch
beyond, at 2°.

It appears then that the exterior heating effect is not produced

1824.] Royal Society. 149

in proportion to the darkness of colour in the bulb, but is more
developed by a thicker and rougher coating, not so sensible
to light, but more so to simple radiant heat.

A variety of different coatings were then tried, with many of
which an exterior effect was produced nearly equal to that in the
red rays.

These coatings being described and arranged in the order of
the greatest exterior effect relatively to the interior, the general
result was, that the magnitude of exterior effect, though doubt-
less caused in some degree by secondary light refracted to that
position, is chiefly attributable to a peculiar heating power
which differs in nature from that acting within the visible spec-
trum, in the circumstance of its being more developed by such
surfaces as are known to be most sensible to the absorption of
common non-luminous radiant heat, without reference to darkness
of colour, or absorptive power for light.

Coatings equally described as black may be very different in
their power of absorbing simple heat, and to some slight differ-
ence of this sort in the coatings of the thermometers employed,
it is highly probable that much of the discrepancy between
different celebrated observers may be attributed.

The exterior effect being shown to be analogous in its proper-
ties to simple heat, an attempt was made to ascertain whether it
radiated in any specific direction ; for this purpose a plate of
glass, which stops common radiant heat, was interposed a little
below the prism, but produced no diminution of this effect.
When it was placed parallel to the red rays, and forming a sort
of boundary to them, so as to intercept any effect coming out-
wards from them, the heating effect was greatly diminished.

From all these experiments, the conclusion seems to be, that
the red rays acquire a power of radiating heat outwards from
their own particles.

In a supplement, the author describes a heating effeet exterior
to the cone of light formed by a lens, affected like the former by
the nature of the surface on which it acts. He also states,
that he has investigated other phenomena connected with these,
which may probably tend to afford an explanation of many of
the relations of light to heat.

A communication was also read, " On the North Polar Dist-
ances of the principal Fixed Stars, by J. Brinkley, DD. FRS."

In this paper Dr. Brinkley controverts the statements of Mr.
Pond respecting the southern motion of the fixed stars, as given
in the Philosophical Transactions for 1823 ; and altogether
denies the validity of that astronomer's conclusions on the sub-
ject. He shows that the Greenwich and Dublin Catalogues of
1813 dirler merely a few tenths of a second, and those of 1823
still less ; and he ascribes the appearance of a southern motion
to a slight error in the Greenwich Catalogue of 1813. In endea-
vouring to prove this, Dr. B. adduces the observations of Brad-
ley in 1728, of'Cassini in France in 1740, of Dr. Maskelyue at

150 Proceedings of Philosophical Societies. [Feb.

Schehallien, of Piazzi at Palermo, of Mudge in England in 1802,
and of Lambton in Hindostan in 1805. The Westbury obser-
vations, he remarks, differ too much from the Greenwich to be
available in this question ; and those of Mechain are opposed by
others made with better instruments. Mr. Pond has diminished
the quantities in Dr. Brinkley's Catalogue, by applying Brad-
ley's refraction, while he leaves M. Bessel's in their original
form ; and is thus enabled to place his own as means between
them : to which mode of correction, however, Dr. Brinkley
strongly objects. The question of Parallax, Dr. B. considers,
is still quite open for discussion ; but its consideration he defers
for the present. Various tables are annexed to the paper, in
illustration of the statements it contains.

A paper was likewise communicated, " On the Figure requi-
site to maintain the Equilibrium of a homogeneous fluid Mass
that revolves upon an Axis ; " by James Ivory, Esq. MA.
FRS.

The Society then adjourned over the Christmas vacation, to
meet again on Thursday the 8th of January.

Jan. 8. — At this meeting, Anthony M. R. Story, Esq. was
admitted a Fellow ; and the reading was commenced of a paper,
entitled, " Observations on the Positions and Distances of
Three Hundred and Eighty Double and Triple Fixed Stars, made
in the Years 1821, 1822, and 1823;" by J. F. W. Herschel,
Esq. FRS. and J. South, Esq. FRS.

LINNEAN SOCIETY.

The meetings of this Society were resumed on the 4th of
November. Among the presents then on the table were speci-
mens of eighty-five species of birds sent from India, by Major-
Gen. T. Hardwicke, FRS. and FLS., comprising many rare and
several new species ; and with them was a curious species of
musk rat ; and also the head of Antilope Quadricornis, the Chi-
kara of Bengal, a notice of Gen. Hardwicke's description of
which, read before the Society on the 17th of June last, will be
found in the Annals for the succeeding August.

The following communications were read :

" A Description of the Swallow-tailed Falcon, Falcofurcatus,
Linn, taken near Havves, in Wensley Dale, Yorkshire, in 1805 ;"
and, " A Description of a Bird, supposed to be the Rallus
pusillus of Latham, shot at the same place in 1807 ;" by W. Fo-
thergill, Esq. communicated by Dr. Sims, FLS.

Observations on the Genus Onchidium of Buchanan, with a
Description of a new Species ; by the Rev. Lansdown Guilding,
FLS.

In this paper Mr. Guilding gives an improved generic charac-
ter of Onchidium ; class Mollusca: ord. Cephala; div. Ga$tero~
poda : " Corpus oblongum, repens, subtus planum. Penula car-
nosa pedem totum tegens. Os anticum, longitudinale. Anus pos-
ticus, infra, Tentacula duo retractilia. Oculi terminales." He

1824.] Linnean Society. l&l

enumerates six species, including a new one thus characterized :
" O. occidentale, durso fusco, atomis brunneis elevatis sparsis,
ventre pallido, lateribus livido-maculatis, brachiis apice divisis."
Found in moist places of the mountainous parts of St. Vincent's.

Nov. 18. — The reading was commenced of a paper, entitled,
" Experiments and Observations on the Light and Luminous
Matter of the Lampi/ris noctiluca, or Glow-worm;" by John
Murray, FLS.

Dec. 2. — The reading of Mr. Murray's paper was continued ;
and the following communication was also read :

" Descriptions of nine new Species of the Genus Carex,.
Natives of the Himalaya Alps in Upper Nepal; " by Mr. David
Don, Librarian to the Linnean Society.

These Carices were sent to A. B. Lambert, Esq. VPLS. by
Dr. Wallich ; they bear a greater resemblance to the European
than to the American species. Mr. Don, in describing them,
has taken for his model the Bishop of Carlisle's Monograph of
the British species, in vol. xi. of the Linnean Transactions ; their
specific characters are as follows :

1. C. nubigena, digyna; spiculis subnovenis ovatis confertis,
arillis ovatis striatis rostratis bifidis margine denticulato-scabris,
glumis ovatis acuminatis, culmo striato nudo inferne tereti, foliis
involutis. — 2. C. foliosa, digyna ; spica elongata, spiculis
ovato-oblongis adpressis ; inferioribus subremotis, arillis ellip-
ticis rostratis bifidis margine laevibus, glumis ovatis aristatis,
culmo acute triquetro scabro, foliis planis. — 3. Cflexilis, digyna ;
vaginis elongatis pedunculo brevioribus, spicis filiformibus cer-
nuis apice masculis, glumis ellipticis acutis, arillis ovatis striatis
pilosis rostratis. — 4. C. macrolepis, digyna; vaginis elongatis
pedunculo brevioribus, spicis strictis cylindraceis apice masculis,
glumis lanceolatis longicuspidatis, arillis ovatis rostratis scaber-
rimis costatis apice bipartitis. — 5. C. longipes, digyna; vaginis
elongatis pedunculo 4-plo brevioribus, spicis cylindraceis erectis
apice masculis, glumis ellipticis aristatis, arillis ovatis costatis
glabris rostratis. — 6. C. aristata, trigyna; vaginis elongatis sul-
catis, spicis cylindraceis strictis apice masculis ; terminalibus
omnino masculis, glumis late ellipticis aristatis, arillis ovalibus
triquetris rostratis scabris. — 7. C. chlorostachya, trigyna; vaginis
nullis, spicis fcemineis cylindraceis erectis pedunculatis ; mascu-
lis solitariis, glumis ovato-lanceolatis acuminatis apice scabris,
arillis ventricosis costatis apice rostratis bifurcis gluma longiori-
bus. — 8. C. lenticularis, digyna; vaginis nullis, spicis fcemineis
filiformibus pedunculis patuiis ; masculis solitariis pedunculatis,
glumis cuneatis : acumine longo spinuloso, arillis cuneato-orbi-
culatis papilloso-micantibus compressis marginatis. — 9. C. «/<>-
pecuroides, trigyna ; vaginis nullis, spicis fcemineis erectis cylin-
draceis subsessilibus ; masculis solitariis, glumis ellipticis acumi-
natis superne scabris, arillis lanceolatis compressis hevibus apice
truncatis emarginatis.

152 Proceedings of Philosophical Societies. [Feb.

ASTRONOMICAL SOCIETY.

Nov. 14, 1823. — This Society held its first meeting after the
late recess this evening, when a paper by G. Dollond, Esq. was
read, descriptive of a new instrument of his invention for mea-
suring vertical and horizontal angles in practical astronomy.
The instrument was- exhibited in the room, and consists of two
telescopes, two vertical divided circles, and an artificial horizon,
by means of which the object is seen by direct and reflected
vision ; and no less than 32 distinct readings may be obtained
of each observation, without the usual attention to levelling the
instrument.

An elegant inkstand was presented for the Society's table, and
many other valuable presents were received.

The honorary medals we before alluded to (Annals, N. S. vi.)
were officially announced from the chair this evening; viz.
the Society's gold medals, to Charles Babbage, Esq. for his
valuable invention of applying machinery to the purposes of cal-
culation, and to Prof. Encke for his investigations relative to the
comet which bears his name. The silver medals of the Society,
to Mr. Rumker for the re-discovery of M.Encke's comet in 1 822 ;
and to M. Pons for the discovery of two comets in the same
year, as well as for his great zeal and perseverance in cometary
astronomy. These medals are to be presented at the ensuing
anniversary of the Society in the present February.

Dec. 12. — The papers read this evening consisted of a very
able and elaborate preface which had been prepared by J. F. W.
Herschel, Esq. the Foreign Secretary, at the request of the
Council, to a series of tables for calculating the places of the
principal fixed stars, which have been computed by order of the
Society ; and will be printed in the forthcoming volume of its
memoirs, and a supplement to a paper before read on the theory
of astronomical instruments, bv Benj. Gompertz, Esq. FRS.and
MAS.

Jan. 9. — The papers read at the meeting of this evening were
as follows :

Observations on the Comet of 1811 taken at the Havannah,
by Don Joseph Joachim de Ferror of Cadiz, deceased, commu-
nicated by the President.

These observations were accompanied by computations of the
comet in an elliptic orbit, and the elements are very nearly the
same as those brought out by M. Argelander.

On the Constants of Deviation occurring in the Reduction of
Astronomical Observations, by Benj. Gompertz, Esq. FRS. and
MAS.

This paper examines the causes of deviation, and proposes
formulae for their more easy reduction ; it is, however, so purely
mathematical as not to admit of abridgment within our limits.

On the Opposition of the Planet Mars, which will take place

1824.] Geological Society. 153

on the 24th of March next ; by Francis Baily, Esq. FRS. and
VP. Ast. Soc.

This paper we have obtained permission to print at full length ;
see p. 107 of our present number.

GEOLOGICAL SOCIETY.

Nov. 7. — A letter was read, dated May 10, 3 823, from George
Cumberland, Esq. Hon. Mem. GS. " On a Fossil of the Chalk,"
accompanied by a drawing.

A letter was read, dated July 14, 1823, from George Cumber-
land, Esq. Hon. Mem. GS. " On a new Species of Encrinus
found in the Mountain Limestone, near Bristol."

A notice was read, containing an Analysis of the Aluminiteof
St. Helena, by Dr. Wilkinson, of Bath : communicated by Col.
Wilks, MGS.

On this analysis Col. Wilks observes, that there is a remarka-
ble difference between the component parts of the aluminite of
St. Helena, and the sub-sulphate of alumine found at Newhaven
and Halle, as given by Phillips, p. 111.

A paper was read on the Geology of Parts of the Islands of
Madeira, Porto Santo and Baxo, by T. E. Bowdich, Esq.

From the investigations of Mr. Bowdich, it appears that such
parts of these islands as he examined consist principally of hori-
zontal strata of limestone and sandstone containing fossils, inter-
sected, and sometimes capped by basalt.

Nov. 21 . — An extract of a letter was read from the Rev. Lans-
down Guilding, MGS. containing an Account of a Fossil found
in the Blue Lias at the Berkeley Canal, near Gloucester, accom-
panied by the Fossil.

A paper was read, " On the Lias of the Coast in the Vicinity
of Lvme Regis, Dorset," by H. T. de la Beche, Esq. FRS. FLS,
and MGS.

In a former communication in the first part of vol. i. second
series, of the Society's Transactions, the author had presented an
outline of the geological features of the coast near Lyme Regis.
The present paper is intended as supplementary, and the sections
before published are referred to. Mr. de la Beche now enters
into a detailed description, illustrated by a drawing, of the various
strata composing the lias formation.

This formation consists of about 110 feet of lias, composed of
more than 72 beds of limestones alternating with the same num-
ber of marl beds, surmounted by about 500 feet of lias marls.
An account is subjoined of the various fossil shells and other
organic remains luund in the lias, accompanied with several
descriptive drawings.

Dec. 5. — A paper was read, entitled " Remarks on the Geo-
logy of Siam and Cochin China, and certain Islands in the
Indian Archipelago, and Parts of the adjacent Continent," by
John Crawford, Esq. MGS.

154 Scientific Intelligence. [Feb.

METEOROLOGICAL SOCIETY.

The second general meeting of this new and promising asso-
ciation was held on Wednesday, Nov. 12, 1823, in pursuance
of the resolutions agreed to at its establishment, as given in
the Annals for Nov. and was very numerously and respectably
attended.

Dr. Birkbeck having been called to the chair, the business of
the evening commenced by the admission of a number of new
members, among whom were W. Allen, Esq. FRS.; W. H. Pepys,
Esq. FRS. ; B. C. Brodie, Esq. FRS.; H. T. Dela Beche,Esq.
FRS.; G. M. Paterson, MD. M. Asiat. Soc. Calcutta, Sec.

The Society then proceeded to the election of a Council and
Officers ; when the following gentlemen were appointed : —

Council.— John Bostock, MD. FRS.; Thomas Forster, MB.
FLS. ; William Shearman, MD. ; C. J. Roberts, MD. ; Luke
Howard, Esq. FRS. ; J. F. Daniell, Esq. FRS. ; Richard Tay-
lor, Esq. FLS. ; E. W. Brayley, Jun. Esq.

President.— George Birkbeck, MD. M. Ast. Soc. MGS. &c.

Treasurer. — Henry Clutterbuck, MD.

A provisional draught of regulations for the government of the
Society having been read, it was referred to a committee for
revision, and the Society then adjourned.

On the 14th of Jan. 1824, a third general meeting took place,
at which the Code of Regulations, as revised by the committee,
was adopted by the Society; and the meeting being then
resolved into an ordinary one, a Report from a Committee
was read, on the objects to which the attention of the
Society should primarily be directed ; together with a paper on
the Vernal Winds, by John Gough, Esq. of Kendal, and several
other communications ; all which we hope to notice more parti-
cularly in our next.

Article XXI.

SCIENTIFIC INTELLIGENCE, AND NOTICES OF SUBJECTS
CONNECTED WITH SCIENCE.

I. Dark and bright Lines traversing the Spectrum.

(To the Editor of the Annals of Philosoji/iy.)
SIR, Jan. 14, 1824.

In your number for August, 1822, a short notice appears respecting
the prismatic experiments of M. Frauenhofer, a full account of which
is given in the Edinburgh Philosophical Journal, No. 18, p. 288, and
continued in the subsequent number. You will, perhaps, allow me to
trespass upon a small space in the next number of the Annals in order
to make a remark relative to the subject of the papers alluded to,

1824.] Scientific Intelligence. 155

which I am induced to do from not finding it done from higher quar-
ters. The observation I wish to make is this, that although we must
allow M. Frauenhofer full credit for having first minutely described the
position of various dark and bright lines traversing the spectrum, and
having employed them as definite points for measuring the dispersion,
yet the fact of the existence of such lines has been for some years known,
though not, perhaps, so generally as it deserves to be. 1 beg to refer
such of your readers as may not be acquainted with it, to a paper by
Dr. Wollaston in the Phil. Trans, for 1802, p. 378, in which the exist-
ence of such lines under particular circumstances is described as
observed by the author. Another observation connected with the
same phenomena will be found in p. 380 of the same paper ; and in the
same volume, p. 395, in a paper by Dr. Young, an important observa-
tion is made, bearing on the theory of the phenomena.

I am, yours, &c. B. P.

II. Analysis of Cleavelanditefrom Finland.
M. F. Tengstrom finds this substance to be composed of

Silica 67-99

Alumina 19*61

Soda 11-12

Lime 0-66

Oxide of manganese 0-4-7

Oxide of iron 0-23

100-08

III. Copper Pyrites of Orijarva.

M. V. Hartwall. of Abo, has analyzed the copper pyrites of Orijarva,
with the following results :

Sulphur 36-33

Copper 32-20

Iron 30-03

Silica 0-93

Oxide of mang. and earthy matter. 1-30

10079
The author of this analysis remarks, that its results nearly agree with
those given of the copper pyrites of Cornwall, given in the Annals,
vol. iii. N. S.p. 300.

IV. Scapolite from Pargas.

The last named chemist has also given an analysis of a new species of
scapolite from Pargas : it consists of

Silica 4942

Alumina 25-4-1

Lime 1 5'59

Soda 6-05

Oxide of iron 1 40

Magnesia 0'68

Oxide of manganese 007

Loss by heat MS

100-07

156 New Scientific Books. [Feb.

VII. Manufacture of Pianoforte Wire.
(To the Editor of the Annals of Philosophy.)

SIR, London, Oct. 8, 1823.

I should feel much obliged to you, or any of your correspondents,
for the communication of any particulars respecting the manufacture
of pianoforte wire, and the cause of the very decided superiority of
what is called Berlin steel wire over all that is made in England. Have
any of the new alloys of steel and silver, &c. or has Mr. Brookedon's
method of drawing through conical holes made in diamonds, rubies,
sapphires, or other hard stones, been tried, to make pianoforte wire ?
Considering the great quantity and value of the wire used in musical
instruments, made in the greatest perfection in this country, it is to be
lamented that our wire-drawers suffer themselves to be excelled by
foreigners.

What mode of whitening brass wire will best preserve it from oxi-
dizement, and least injure its elasticity?

I am, Sir, your constant reader, M. A.

Article XXII.
NEW SCIENTIFIC BOOKS.

PRF.IUH.IVO FOR PUBLICATION.

Dr. Uwins will shortly publish a Compendium of Medical Theory
and Practice, founded on Cullen's Nosology. ]2mo.

Thomas Sandwich, Esq. has in the press an Introduction to Anatomy
and Physiology; in a duodecimo volume.

James Buckingham, Esq. Author of ' Travels in Palestine,' will
shortly publish ' Travels among the Arab Tribes inhabiting the Coun-
tries East of Syria.'

An Account of the Life and Writings of the late Thomas Brown,
MD. Professor of Moral Philosophy, Edinburgh; by the Rev. David
Welsh.

JUST PUBLISHED.

The Westminster Review, No. I. 6s.

A second edition of Mr. Tredgold's Essay on the Strength of Cast
Iron and other Metals, much augmented, particularly in the Experi-
mental Parts, and the Illustration of the Application by popular
Examples.

Pathological Observations ; Part I. — On Dropsy, Purpura, and the
Influenza of the latter end of the year 1822, and beginning of 1823,
&c. By W. Stoker, MD. Senior Physician to the Fever Hospital,
Dublin. Svo. 85.

Edinburgh Medical and Surgical Journal. No. 1. New Series.
8vo. 6s.

An Essay on the Invention* and Customs of Ancient and Modern
Nations in the Use of Wine and other Liquors ; with an Historical
View of the Practice of Distillation. By Sam. Morewood. Svo. 12*.

1824.] New Patents, 157

The Encyclopaedia Metropolitana, Part XI. containing Magnetism
and Electro-Magnetism, &c. ll. Is.

A Toar through the Upper Provinces of Hindostan, between the
years 1804 and 1814; with Remarks and authentic Anecdotes; to
which is annexed a Guide up the River Ganges: with a Map of the
Ganges. 8\o. 9s.

A new Edition of Prof. Buckland's Reliquiae Diluvianae, attesting
the Action of a Universal Deluge: with 27 Plates. 4to. 1/. lis. 6d.

Article XXIII.
NEW PATENTS.

T. Hopper, Esq. Reading, Berkshire, for certain improvements in
the manufacture of silk hats. — Nov. 20.

C. A. Deane, Charles-street, Deptford, Kent, ship-caulker, for his
apparatus or machine to be worn by persons entering rooms or other
places filled with smoke or other vapour, for the purpose of extinguish-
ing fire, or extricating persons or property therein. — Nov. 20.

J. Perkins, Hill-street, London, and J. Martineau the younger, City
Road, Middlesex, engineers, for their improvement in the construction
of the furnace of steam-boilers and other vessels, by which fuel is eco-
nomized, and the smoke is consumed. — Nov. 20.

J. Bourne, Denby, Derbyshire, stone-bottle manufacturer, for cer-
tain improvements in the burning of stone and brown ware in kilns or
ovens, by carrying up the heat and flame from the furnace or fire below
to the middle and upper parts of the kiln or oven, either by means of
flues or chimneys in the sides thereof, or by moveable pipes or conduc-
tors to be placed within such kilns or ovens; also by conveying the
flame of one kiln more into others by means of chimneys, and thus per-
mitting the draft and smoke of several kilns or ovens to escape, where-
by the heat is increased, and the smoke diminished. — Nov. 22.

J. Slater, Saddleworth, Yorkshire, clothier, for improvements in the
machinery to facilitate the operation of cutting or grinding wool or
cotton from off the surfaces of woollen cloths, kerseymeres, cotton
cloths, or mixtures of the said substances, and for taking or removing
hair or fur from skins. — Nov - . 22.

T. Todd, Swansea, South Wales, organ-builder, for his improve-
ment in producing tone upon musical instruments of various descrip-
tions. — Nov. 22.

S. Brown, Gent. Windmill-street, Lambeth, Surry, for his engine or
instrument for effecting a vacuum, and thus producing powers by which
water may be raised and machinery put in motion. — Dec. 4.

A. Buchanan, Catrinc Cotton Works, for a certain improvement in
machinery heretofore employed in spinning-mills in the carding of cot-
ton and other wool, whereby the top cards are regularly stripped and
kept clean by the operation of the machinery without the agency of
hard labour. — Dec. 4.

J. Parkes, Manchester, civil engineer, for a certain method o«f manu-
facturing salt. — Dec. 4.

158

Mr. Hoioard's Meteorological Journal.

[Feb.

Article XXIV.

METEOROLOGICAL TABLE.

Barometer.)

Thermometer.

Daniell's hyg.

1823.

Wind.

Max.

Min.

Max.

Min.

Evap.

Rain.

at noon.

12thMon.

Dec. 1

w

2990

29-69

52

39

—

—

2

s w

29-69

29-69

52

36

—

28

3

s w

29'69

29-45

54

39

—

10

4

w

2993

2950

47

30

—

5

w

2993

29-62

46

32

—

41

6

N E

30-59

29-93

42

28

—

04

7

w

30-59

30-55

36

31

—

8

w

30-55

30-46

44

34

•32

9

N \V

30-51

30-44

44

27

—

10

s w

3051

30-28

44

29

—

11

s w

30-28

29 97

4S

40

—

12

w

30*03

29-91

43

33

—

13

N W

30-34

30-03

40

26

—

14

N W

30-33

50-29

41

31

—

15

N W

30-33

30-31

44

31

—

16

s w

30-31

29-82

47

39

—

—

17

S £

2982

29- 10

48

32

—

38

18

w

2975

29-60

40

30

—

19

N W

2975

29-53

36

26

•45

20

S E

29'53

29-36

45

32

—

10

21

N W

29-76

29-36

50

36

—

—

22

N W

2993

2976

45

30

—

—

23

s w

30-07

29-93

45

36

—

26

M

s w

30-10

30-07

48

42

—

20

25

s w

30-10

29-97

49

39

—

07

26

s w

2997

2939

46

39

—

10

27

s w

29-62

29-39

45

35

—

2S

s w

2962

2937

52

39

—

06

29

s w

29-37

29-27

46

39

—

06

30

s w

29-58

29-27

45

38

—

02

31

w

29-65
3059

29-46
29-10

49

3S

■35

25

54

26

1-12

233

The observations in each line of the table apply to a period of twenty-four hours,
beginning at 9 A. M. on the day indicated in the first column. A dash denotes that
the result is included in the next following observation.

1824.] Mr. Howard's Meteorological Journal, 159

REMARKS.

Twelfth Month.— 1. Cloudy. 2. Rainy. 3. Cloudy and fine : a furious gale from
the W all night. 4. Fine : wind still very high. 5. Foggy morning : cloudy.
6. Rainy morning: cloudy. 7. Foggy. 8. Foggy morning: fine. 9. Fine.
10. Cloudy. II, 12. Fine. 13. Fine: bleak. 14. Fine clear morning: day very
fine: evening foggy. 15. Very fine. 16. Overcast. 17. Rainy: a strong gale of
wind in the evening, accompanied by an uncommonly rapid depression of the barometer.
18. Fine. 19. Foggy: gloomy. 20. Overcast: drizzling. 21. Foggy morning
afternoon fine. 22. Gloomy. 23, 24. Rainy: gloomy. 25. Drizzling. 26. Gloomy]
27. Fine. 28. Drizzling : night stormy. 29. Fine : some rain at night. 30. Cloudy
and fine. 31. Fine day: night windy, with rain.

RESULTS.

Winds : NE, 1 ; SE, 2 ; SW, 13 ; \V,8; NW, 7.

Barometer : Mean height

For the month 29-885 inches.

For the lunar period, ending the 24th

For 1 5 days, ending the 10th (moon south)

For 13 days, ending the 23d (moon north)

Thermometer : Mean height

For the month .39"822

For the lunar period

For 30 days, the sun in Sagittarius

Evaporation j.12 i n .

Rain , _ 2*33

Laboratory, Stratford, First Month, 22, 1824. R. HOWARD^

160 Mr. Howard's Meteorological Journal, [Feb. 1824.

Note— Some doubt having arisen as to the accuracy of the high main lately assigned
to the barometrical observations in this Register, we have thought it needful to verify the
actual height of the barometer employed, by comparison with a good standard.

On the 1 6th inst. at three, p. m. I suspended by the side of the barometer in question,
the one belonging to my friend J. F. Daniell, described in page 338 of his " Meteoro-
logical Essays," and which he considers (with due allowance for the depression of the
column, caused by the smaller diameter of the tube) to agree with the excellent standard
barometer, lately constructed under his direction for the Royal Society. The result was
very satisfactory : the mountain barometer, and that employed for this Register, stood
respectively at 30-66 in. ; nor could a difference of 1-1 00th of an inch be found between
them, by either of two observers, who examined them at intervals during a full hour.
The temperature of each was 55° : the inner diameter of the mountain barometer (the
quicksilver of which has been boiled in the tube), is - 1 5 in. : the inner diameter of the
wheel barometer, as nearly as could be ascertained, 0-23 in. The quicksilver has not
been boiled in this instrument. The barometer was very nearly stationary on the 16th,
from noon to midnight. '

In a comparison made this day, for an hour before noon, in the lower part of the scale,
the instruments at the conclusion stood thus, at temp. 58°.

The siphon barometer '28*94

The mountain ditto 28'895

Difference -045

The correction for the capacity of the cistern in the mountain barometer being applied
reduces the difference in the present case to -014, and creates a difference in the former
of - 01 1 in. both in excess on the part of the siphon barometer. The corrections for tem-
perature and capillary depression cannot here be so accurately applied, on account of the
different construction of the two instalments. On the whole, there appears no ground
to disturb the adjustment of our own barometer.

Tottenham, FlMt'Mmth, 23, 1824. L. HOWARD.

ANNALS

OF

PHILOSOPHY.

MARCH, 1324.

Article I.

On the Crystalline. Forms of' Artificial Salts.
By H.J. Brooke, Esq. FRS.
(Continued from p. 117.)
Tartrate of Potash.
The primary form is a right oblique
angled prism, with cleavages parallel to
the lateral planes.

M on T 89° 30'

M one 142 13

M on b 107 30

Tone 127 17

Ton V 103 40

Bitartrate of' Potash.
It has been already observed by Dr. Wollaston, that the
cleavages of the crystals of this salt are parallel to the lateral
planes and diagonals of either a rectangular or a rhombic prism.
From the figures and measurement of seve-
ral crystals, I am indncedto adopt the right
rhombic prism as the primary form. The
annexed figure represents the planes which
occur on many of the crystals placed symme-
trically in relation to the primary planes.

MonM' 107° 30'

M on h 126 15

M on 6 117 2

conh 125 30

cone' 109

b on V" 77

New Series, vol. vii. m

162 On the Crystalline Forms of Artificial Sails. [March,

There is a bright cleavage parallel to the edge between M and
M' and perpendicular to A, and consequently parallel to the great
diagonals of the primary terminal planes. The crystals may be
also cleaved parallel to A, and to M and M'. The figure, it has
been observed, is symmetrically drawn, but the crystals are
frequently much distorted by the disproportionate extension of
some planes and the disappearance of others ; so that it is not
always easy to compare them with any general type of the
whole. We may, however, be much assisted in this comparison
by the character of the plane //, which, in all the crystals I have
seen, is striated, as shown in the figure. By the assistance of
this plane, and the bright cleavage plane perpendicular to it, and
by measurement, we may be enabled to compare the crystals
with the enoraved figure, however irregularly formed they may
be. On very many of them the planes b and b'" are so much
enlarged as nearly, if not entirely, to exclude the other four
plane> which appear in front of the figure; while at the back,
the planes parallel to b' and b" are similarly enlarged. If these
four planes were so much extended as to exclude all the others
which appear on the figure, an irregular tetrahedron would
result.

On some crystals there is one and sometimes two planes
replacing the edge between A and M, one of them measuring
with A about 156°, and the other about 145^°.

titrate of Silver.
Primary form a right rhombic prism.

Pond 116° 36'

Mond 148

MonM' 129 31

d on d' 126 48

On some crystals received from Mr.
Tesch^macher the planes d were barely
visible ; while on others from Mr. Cooper,
those planes encroached so much on M
and M' as to leave only minute portions
of these visible.

1824.] Variation of the Horizontal and Dipping Needles . J 63

Article II.

Observations and Experiments on the daily Variation of the
Horizontal and Dipping Needles under a reduced directive
Power. By Peter Barlow, Esq. FRS. of the Royal Military
Academy.*

It is now just a century since Mr. Graham discovered the
daily change in the variation of the horizontal needle, subsequent
to which time numerous observations have been made on the
same subject by Wargentin, Canton, Gilpin, Col. Beaufoy, and
others, which have all confirmed, with certain shades of variety,
the general fact as first described by the ingenious philosopher
above named.

The actual daily change, however, is so small, even in the
horizontal needle, that it can only be detected with the most
careful observations and with the most delicate instruments ;
and in the dipping needle that change, if any, is so extremely
minute, as hitherto to have escaped observation ; for it was only
in the year 1820, that the Royal Academy of Sciences of Copen-
hagen proposed the determination of this motion, on satisfactory
experiments, as the prize subject for that year ; but the prize, I
understand, has never been adjudged, no satisfactory communi-
cation having been received.

Under this difficulty of observation, it occurred to me, that it
would be possible to increase this deviation on both needles, so
as to render it distinctly observable, by reducing the directive
power of the needle by means of one or two magnets, properly
disposed to mask, at least in part, the terrestrial influence ; a
method which has been long practised by mineralogists and
others, when the object has been to detect minute attractions
I expected by this means that the cause, whatever it might be,
that produces the daily variation, would exhibit itself in an
increased degree, and thereby render the results more perspicu-
ous, and fix with more precision than has hitherto been done, the
time of change and moment of maximum effect.

Suppose, for example, that a finely suspended horizontal
needle, under the natural influence of the earth, makes one
vibration in 2", and that by masking the terrestrial influence by
magnets properly adjusted, that time of vibration is increased to
8" ; then it would follow that the directive power was reduced to
one-sixteenth of the former, and consequently, that any lateral
magnetic force acting upon the needle would produce an effect
sixteen times greater than before ; so that if the former were
12', the new effect or deviation might be expected to amount to

« Abstracted from the Phil. Trans, for 1823, Tart II.

m2

164 Mr. Barlow on the daily Variation of the [March,

between three and four degrees, and therefore be such as to
admit of distinct and satisfactory observation.

A course of experiments carried on for a few days, convinced
me that my ideas were correct, and that we might, while the
needle was kept in its natural meridian, or rather adjusted to that
direction, produce a daily variation to almost any amount. I
obtained, for instance, the first day, a maximum deviation of
3° 40' ; the second, I increased it by bringing up my magnets
to 7° ; the third day I reduced it to 2°, and so on. I found also
that a very considerable daily change would exhibit itself with
the north end held to the south, to the east, west, and, in short,
in any position at pleasure, at least within certain limits, which
will be pointed out as we proceed.

For this it is only necessary, first, to deflect (he needle by
repulsion into any required position, and then, by means of
another magnet, to modify its directive power, in the same way
as when in its natural meridian. Or the same may be done by
bringing two magnets with their contrary poles pointing inwards,
and each opposite to the pole of the same name of the needle
placed between them, and by a slight adjustment of the former
to produce the deviation in question ; or, which is perhaps still
better, the opposing magnets may be brought into the actual
direction of the dip, and then adjusted to produce the deflection
required.

Having mentioned my ideas and first experiments to my
colleague, Mr. Christie, and having expressed a wish that he
would repeat them for the sake of verification, he very readily
agreed to undertake a complete set, with the needle in its natu-
ral meridian, by means of a very delicate compass, and an appa-
ratus he had employed for other experiments, and which admitted
of his bringing his neutralizing magnets very exactly into the
line of the dip. In the mean time I proposed to undertake the
observations on the dipping needle, and on the horizontal needle
in different directions ; viz. with its north end pointing to the
south, east, west, Sec. Having, however, met with some embar-
rassment in the commencement, and having employed, in con-
sequence, a longer time in the observations than I had antici-
pated, Mr. Christie, after having finished his observation in the
meridian, continued them at other points, and has thereby
detected several curious and minute peculiarities, which, with his
other experiments, will, I hope, accompany this memoir.*

Account of' the Observations made on the daily Variation of the
Horizontal Needle in various Directio)is.

My first experiments, as I have already stated, were only
matters of trial, from which 1 had merely ascertained that the

• Mr. Christie has detailed his experiments in an extended paper, whieh succeeds
Mr. Barlow's present communication in the Phil. Trans.

1824.] Horizontal and Dipping Needles. 165

idea I had formed was practicable, and that in certain situations
the needle had certain directions of motion, but I had obtained
no numerical results. Having', however, provided myself with a
needle proper for the purpose, very delicate and light, and eight
inches and a half in length, I began, towards the end of March,
to register the amount of the daily change at every hour, or half
hour, from morning to night ; my son taking the observations
during my occasional absence.

My first observation in the new series was made with the
north end of the needle pointing to the west, balanced in that
position with two magnets placed to the southward attracting
each extremity ; the directive power was considerably reduced,
and I obtained a maximum deviation of 3° 15'; which happened
at about eleven o'clock in the forenoon, and from which time the
variation decreased to a late hour in the evening. The needle
was kept in this position for three days, with some change of
directive power, but the character of the results, as to the direc-
tion of motion, the times of commencement and maximum, Sec.
were of precisely the same nature, but the amount was more or
less, according to the directive power left upon the needle.

Having, however, after a few days, removed my apparatus from
the room in which the experiments had hitherto been made, into
a bower in my garden, and having detected a remarkable differ-
ence in the results obtained in these two situations, I determined
to commence the experiments de novo in this latter spot, which
was at least thirty yards distant from any building ; and after-
wards to examine the cause of the difference in question. This
examination is reported in the conclusion of this article.

[Mr. Barlow here gives a series of tables of observed daily
variations, with the north end of the needle directed to the fol-
lowing points of the compass respectively : — north, south,
north-east, south-we&t, east, west, south east, north-west, north
north-east, south-south-west, east-north-east, west-south-west,
east-south-east, west-north-west, snuth-suuth-east ^ south, (ex-
act bearing N. 10° W. and S. 16° E.) and north-north-west.]

From the above results, although the experiments were not made
under such favourable circumstances as 1 could wish, we may
draw some very curious, if not important conclusions; such, for in-
stance, as the following. That while the north end of the needle
is directed to any point from the south to NNW, its motion during
the forenoon is towards the left hand (the spectator facing the
north end of the needle) ; advancing therefore to some point be-
tween the NNW and north ; and while it is directed towards any
point between the north and SSE it passes to the right hand, that is
still to some point between the north and NNW ; the south end of
the needle at the same time passing of course to some point be-
tween the south and SSE ; so that it would seem that there ought
to be some direction between those limits, viz. between the N and
NNW, and the S and SSE, in which the daily motion is zero, or

166 Mr. Barlow on the daily Variation of the [March,

at least a minimum ; but whether this is a fixed direction during
the year, or whether it has any vibratory motion as the sun
changes its declination, or even during his daily course, is a
question which cannot be decided without a much longer course
of experiments than those I have here the honour to present.

It is also questionable, whether the direction of this line of
no daily variation is the same in different parts of the world ; a
point on which I hope to obtain some information in the course
of the present year. Mr. Forster,* of H. M. S. Griper, having
very obligingly undertaken to repeat my experiments at Spitzber-
gen, during the stay of the vessel at that place for the pendulum
experiments ; and from which we may hope to derive some inte-
resting deductions, particularly in reference to the influence of
the direction of the solar rays ; for it is clear from the experi-
ments reported in the preceding table, that the amount of the
deviation does not entirely depend upon the moment when the
heat of the sun is the greatest, as has been generally imagined ;
for the time of the maximum deviation varies from eleven
o'clock in the morning to four o'clock in the afternoon, accord-
ing to the direction in which the needle is pointed, and to other
circumstances that will be mentioned in the conclusion of this
article. Mr. Christie's observations are also of a kind to throw
great light on this subject.

Another conclusion, which I think we are justified in drawing
from the above experiments, is, that the daily change is not
produced by a general deflection of the directive power of the
earth, but by an increase and decrease of attraction of some
point situated between the north and NN vV, or between the south
and SSE ; for 1 cannot conceive any other hypotheses that will
account for two needles, situated as in these experiments, both
approaching and both receding at the same time to and from the
line of no daily variation ; nor for the total suspension or equi-
vocal vibratory motion of a needle when placed towards this
direction.

I am sorry, that not foreseeing at the commencement of my
experiments, the length to which I should carry them, I did not,
from the first, register the temperature and state of the atmo-
sphere ; for from certain notes of this kind made lately, it
appears to me that the quantity of daily change depends in a
greater degree on the intensity of the solar light, than on the
mere temperature of the day ; although it is certain, from some
recent experiments by Mr. Christie, that the change of tempera-

* I am already highly indebted to this gentleman for the accurate and satisfactory
observations he made during the recent voyage of H. M. S. Conway, under the com-
mand of Capt. Basil Hall, on the method I had the honour to propose for correcting the
local attraction of vessels ; and it is with great pleasure that I find he has been directed
by the Admiralty to continue his attention to them in the present voyage of the Griper.
My best thanks are also due to Capt. Hall, for the facilities he afforded in the instance
abovementioned, and for the judgment with which he selected the most appropriate
situations for submitting that method to the test of actual experiment.

1824.] Horizontal and Dipping Needles. 167

ture of the air, during the day, has a much greater effect upon
the intensity of action in the opposing magnets, than I could
possibly have imagined.

On the daily Variation of the Dipping Needle.

Notwithstanding my observations on the daily change of this
instrument have not been so successful as those on the horizon-
tal needle, yet it will be proper to say a few words on the sub-
ject of the experiments, although I do not intend, in the present
instance, to give any numerical results ; those I have obtained
not being so uniform as I could wish, nor such as to justify their
publication.

The instrument I employed was made by Messrs. W. and T.
Gilbert : it was remarkably free and accurate, and certainly gave
results with greater uniformity than any dipping needle I ever
used. The needle was only six inches in length, a quarter of an
inch broad, and very thin ; it performed in the meridian forty-
one vibrations in one hundred seconds, when under the usual
terrestrial influence ; and when masked and adjusted by two
magnets placed in the line of the dip, it made only fifteen vibra-
tions and a half in the same time; the power was therefore
reduced about eight times.

It is not necessary to explain here the means that I employed,
and the precautions I took to ensure stability ; it will be suffi-
cient to observe, that 1 paid the utmost attention to this essen-
tial condition, and that 1 believe my want of success did not
arise from any defect in this part of the process, but from the
extreme delicacy of this instrument, and the consequent diffi-
culty in adjusting it when under the influence of the neutralizing
magnets. I tried its action for three weeks in the house, but
the jarring of doors and other circumstances prevented me from
drawing any conclusions. I then removed it to the garden, to
a spot well protected by trees and shrubs, and fixed the entire
apparatus to my garden wall, which is exactly in the magnetic
meridian ; and further sheltered the whole in the best way I
could from the effects of the wind and weather. Indeed the
only inconvenience was that I could not leave the needle out in
the night, and could therefore only notice what took place in the
day time, and this, as I have said above, was not so uniform as I
could have desired.

In general a motion commenced soon after the instrument
was adjusted in the morning; but it was not of that gradual and
progressive kind which indicated an uniformly increasing or
decreasing power, as in the other instrument; it passed, for
instance, suddenly from one half or quarter degree, to another
more or less, and which sometimes in the course of the day
would give a difference in the dip to the amount of a degree ami
a half, or even more, but 1 seldom saw in it a tendency to

168 Mr. Barlow on the daily Variation of the [March,

return ; although when I vibrated it towards night, it commonly
took up its morning position. I made these observations with
the needle in various directions, viz. with the face of the instru-
ment to the east, west, north, south, Sec. but in every case I
obtained the same sort of daily motion. The question, there-
fore, respecting the law of variation of this instrument, still
remains to be submitted to fixed principles, although there can
be no longer any doubt that it is subject to a daily change.

On a curious Anomaly observed between the daily Variations in-
doors and in the open Air.

I have already mentioned that I was, at the commencement
of my experiments, a good deal embarrassed and delayed by
certain anomalies which I noticed between the daily changes of
the needle made in the house and in the garden. These maybe
stated shortly as follows. That in certain positions of the needle
towards the east and west, the daily motion, although it pro-
ceeded with the same determinate uniformity in both cases, yet
it took place in different directions ; passing in the one instance
from the east, or west, towards the south, and in the other
towards the north, at the same corresponding hours of the day,
the motion in both instances being equally distinct, regular, and
progressive.

After carefully examining every circumstance that might be
supposed to be the cause of this singular change, I could only
imagine three, that seemed in any way likely to account for it.

1. Were the two magnets and the compass needle in the two
cases in precisely the same relative situation ; and if not, might
not the cause lie in this discrepancy ?

2. The window of the room was to the northward ; was it
possible that the light, arriving at the needle in this direction,
was the cause of the change ?

3. There was an iron stove in the room ; could it be that this
was subject to a periodic increase and decrease of magnetic
power ?

In order to examine the first of these cases, I measured very
carefully the distance, direction, Sec. of the compass and mag-
nets while in the garden, and placed them in precisely the same
relative situation in the parlour ; still the motion in the two cases
was reversed.

To examine the second, it occurred to me that if the direction
of the motion depended upon that of the light, the needle ought
to be wholly stationary in the dark, or when excluded from the
solar rays. I therefore kept my room shut for two days, and
only examined the needle by the light of a wax taper ; but
although there was certainly less motion on those days than
usual, yet I could come to no satisfactory conclusion ; but I
still think that further observations will show that the solar

1824.] Horizontal and Dipping Needles. 169

light,* and not the solar heat, is the principal operative agent in
producing the daily variation. It remained, however, to examine
the third query, which I attempted to do as follows. Having
placed the compass in its former situation in the garden, I fixed
on one side of it a ten inch howitzer shell, in the same direction
with respect to the compass as the stove had in the parlour, and
at such a distance that it might produce a sensible deviation in
the needle, and which I afterwards adjusted to zero by a slight
change in the position of the magnets, thus placing the needle,
as I imagined, under similar circumstances in both cases, with
respect to local attraction ; but, notwithstanding I did in this
way actually produce an alteration in the daily motion, changing
its maximum from eleven o'clock in the morning to about four
o'clock in the afternoon, yet the direction of the motion was the
reverse of what it was constantly found to be in-doors ; the
cause therefore of this perplexing anomaly still remains to be
discovered.

It is proper to observe that Mr. Christie, having made some
of his observations in-doors, and some in his garden, on two
compasses at the same time, found the same reversion of motion
in the two cases. His house is a mile distant from mine ; he
has no stove in the room in which the in-door experiments were
made ; and the only resemblance of situation is, that his window,
like mine, is towards the north. It should be further added,
that this confirmation of the singular anomaly in question did
not arise from his simply repeating my experiment, but grew
naturally out of the particular mode he had adopted to prose-
cute the inquiry ; our experiments, with the exception of the
first suggestion, are independent, and, therefore, where they
both lead to the same result, they may be considered as con-
firming the accuracy of each; and where there is any difference,
they will at least point out those circumstances which require
further investigation.

P. S. The experiments to which I have alluded in p. 16G — 167,
made since this article was written, seem to indicate that this
anomaly, as well as the circumstance there mentioned, may be
occasioned by the daily varying intensity of the opposing magnets.

* I am sorry I have not the necessary apparatus for repeating Morichini's experi-
ment on the violet ray ; but I would suggest to those who have, that the finest test to
which this experiment could be submitted, would be to make use of a needle neutralized
as above desciibed, by which the magnetic property of the ray, if it possessed any,
could not fail of showing itself.

170 Mr. Cooper on an Improved Apparatus for [March,

Article III.

On an Improved Apparatus for the Analysis of Organic Products.
By Mr. J. T. Cooper .* (With a Plate.)

An easy and accurate method of determining the ultimate
elements of bodies composed of carbon, hydrogen, oxygen, and
azote, has been of late years a great desideratum among chemists,
as such a variety of contrivances have been suggested by scien-
tific individuals, all of which have their peculiar merits and
defects. It is presumed the instrument and method of operat-
ing now presented to the Society and the public, if not entirely,
may be considered as nearly free from those objections which, in
my opinion, may be fairly urged against those heretofore in use.
It might, however, be considered ungenerous, was I to take upon
me the task of pointing out those defects, I shall therefore con-
tent myself by briefly stating in this communication, the class
of substances to which it is applicable with a view to determin-
ing the proportions of their elements, and a description of the
method of operating upon each of them.

As this apparatus seems more particularly calculated than any
other for operating on volatile matter, such as the essential oils,
camphor, benzoic acid, and a variety of similar substances, I
shall in the first place describe the method I have adopted in the
analysis of this class of bodies ; and when it is considered that
I write not for those who are accustomed to the more minute and
delicate operations of chemical analysis, but for those who are
or may be considered as unacquainted for the most part with
this subject, I hope I may not be considered as tedious should I
venture to give those directions which to the more matured in
science may seem to be unnecessary.

The oxide of copper used in the experiments is best procured
from the residuum of verdigris (binacetate of copper), which is
or was used to be distilled in glass retorts for the preparation of
strong acetic acid. The reason I prefer the oxide of copper
prepared by this process over any other is, that it is more likely
to be free from impurity than that which is prepared by precipi-
tation from acid solutions. Every one who is in the habit of
preparing precipitates knows the difficulty there generally is in
freeing considerable quantities of precipitated matter from adher-
ing neutral salts ; and as the smallest impurity would in some
measure contaminate the result of the analysis, it is a very
necessary precaution that the oxide, which is by far the greatest
in quantity of any substance that is employed in the operation,
should be perfectly pure. Should it however happen that at any

* From the Transactions of the Society for the Encouragement of Arts, Manu-
factures, &c. Vol. 41.

<4!

^n^^f^^^g^^

CT 1 M | IMI |IIHiMII|lll ^

1 8'24.] the Analysis of Organic Products. 1 J i

time such an oxide is not readily to be procured, the oxide that
is obtained by heating copper plate and quenching it in water
may be substituted ; although I give the decided preference to
the former on account of its mechanical texture being much
more porous, and consequently exposing a larger surface to the
action of substances in vapour passing through it ; neither is it
so likely to choak up the tube and endanger its bursting, and of
course a failure in the experiment. Supposing the residuum
above mentioned to be employed, it is requisite to expose it to a
red heat for twenty minutes or half an hour to destroy the carbo-
naceous matter that invariably accompanies it ; it should then
be pulverised and sifted through a fine wire sieve; that portion
which has passed the sieve being again sifted through a fine
Cyprus or lawn sieve, the finer dust is got rid of, and each of
these portions may be separately kept, and is applicable to dif-
ferent purposes.

A tube of hard glass, either of crown or green bottle glass,
being selected about 14 or 15 inches long, and from one to two-
tenths of an inch internal diameter, clean the inside from dust
by passing through it a piece of cotton, then make it as hot
from end to end as the fingers can conveniently bear, and draw
air through it into the mouth (but not blow through it) while it
is still hot, to ensure its perfect freedom from adhering moisture
on its inside, and while still warm seal up one end with the
blowpipe ; the tube may be now balanced, but it is necessary
in this, as in all other operations of analysis where very small
quantities are concerned, that the beam should be affected by
1-200 or 1-300 of a grain, even when loaded with 400 or 500
grains at each end.* The substance intended for analysis is
now to be introduced into the tube ; if it be solid, as for instance
camphor or a like substance, it may be broken into small frag-
ments and shaken down to the bottom ; if it be a fluid, as a
volatile or fixed oil, it may be introduced by means of a small
funnel, as is shown in fig. 7 (Plate XXVII), which funnel is pre-
pared, on the instant, from a piece of flint glass tube of conve-
nient size and substance by heating it near one of its extremities,
and suddenly drawing it out ; it is evident the semifluid glass will
be thus elongated, and a funnel with nearly a capillary tube and
of any required length, may be thus obtained ; a very little prac-
tice will render this part of the business very easy to be accom-
plished ; the funnel is to be put into the tube, reaching very
near its bottom or sealed end, and the fluid matter introduced
without soiling the upper part of it ; care must also be taken on
withdrawing the funnel, that no portion of the fluid is attached
to its lower extremity, or otherwise this will happen. The vola-
tile substance, or that which is capable of being rendered so by

* The balance I have been in the habit of using was made for me by Mr. Robinson,
anil is sensibly affected by l-400th of a grain when loaded with 1000 grains at each
end.

172 Mr. Cooper on an Improved Apparatus J br [March,

a red heat, being now introduced into the tube, its weight is to
be very carefully taken, which, when done, the oxide of copper
previously freed from its fine dust by the lawn or Cyprus sieve,*
and recently heated red hot, is to be poured into the tube while
warm, to the length of eight or ten inches, having previously put
into the tube as much only of perfectly cold oxide as will absorb
the fluid portion of matter, and about a quarter of an inch above
it, or to stand about the same height above the solid substance.
Why I recommend the present proceeding is, that a small quan-
tity of the cold oxide only is used to prevent the hot oxide from
coming in contact with the volatile matter which might other-
wise endanger the escape of a small portion from the tube, and
of course would give erroneous results; and that portion of cold
oxide, even if it be fully saturated with moisture, can contain
such a very minute quantity of water as not to sensibly affect
the accuracy of the analysis. Having proceeded thus far, a
quantity of recently ignited asbestos, or spun glass (the former
is best), is put into the tube, so as to occupy an inch or two, de-
pending on the quantity of water that is expected to be formed;
this must not be crammed, but put rather lightly into the tube.
The tube is now to be bent as represented in fig. 1, and its
weight may be again taken, but this is not absolutely requisite ;
it is, however, well to do it. The tube is then to be covered
with thin sheet copper, and placed between the forceps, as
represented in the same figure, with its open extremity inserted
under a jar in the ordinary mercurial pneumatic trough, or it
may be connected with a gasometer of Mr. Pepys's construction,
which, when ten or twenty grains of a substance are employed,
and the quantity of either carbon or azote it contains is consi-
derable, is convenient. Small mercurial graduated jars may be
used, even if very large quantities of gas are obtained, as the
process of decomposition may at any time be stopped almost instan-
taneously^ and the quantity contained in them being registered,
they may be alternately filled with mercury and displaced by the
gaseous products, as long as any comes over, reserving only the
last portions for examination, of which a few cubic inches alone
are requisite.

The lamps being trimmed with very short wicks are now to be
lighted, lighting those first that are nearest the gasometer, and
when the tube is red hot, the remaining ones may be set fire to
in succession, until the whole length of tube that is filled with
the oxide is red hot. One set of lamps for a tube, of the size I
nave mentioned above, is generally sufficient, but should tubes
be used of larger size, such as half an inch in diameter, both sets
will then be required. In coating the tube with sheet copper

• The finer portion is taken from the oxide to allow more freedom of passage for the
vapour through it ; in some cases the rush of gas is so sudden, was it not for this precau-
tion, it would be likely to burst the tube.

+ I consider this as one of the advantages of this apparatus.

1824.] the Analysis of Organic Products. 173

care must be taken not to cover that part of it which contains
the asbestos, otherwise the heat will be conducted by it to that
portion of tube, and prevent the condensation of the vapour of
water, which is very essential ; and in placing the tube between
the forceps, it will be convenient to allow that part of it which
contains the volatile matter to project beyond the forceps ; the
heat that is conducted by the copper coating is generally enough
to volatilize most substances. In the analysis of substances
containing much hydrogen, and especially when ten or twelve
grains of them are taken, it will be found convenient to attach
to the tube a small bulb to contain the water that is generated :
this is represented by fig. 6. I believe I have stated the whole
that is necessary as respects the management and use of this
apparatus as far as regards the decomposition of volatile sub-
stances ; in the next place, I shall speak of its application to the
decomposition of fixed substances, which after what has been
said will require but very few words.

If the substance be a vegetable salt, it must be freed from all
extraneous moisture; this is best effected by suffering it to
remain over an hygrometric substance in vacuo for some time.

Those who have not the convenience of an air-pump, may
content themselves by operating in this way, which, although
not quite so elegant, answers the purpose extremely well. A
wide-mouthed phial provided with an accurately-ground stopper
being procured, select another and much smaller phial that will
easily go into it, and allow the stopper of the larger one to close
accurately ; it is as well to apply a little tallow to the stopper to
ensure its more perfect fitting ; strew on the bottom of the
larger phial a quantity of chloride of calcium (dry muriate of
lime), put into the smaller phial the substance in fine powder
intended to be dried, and place this in the larger phial standing
on the chloride ; moisten a small piece of bibulous paper with
alcohol, and put it into the larger phial, but not inside of the
smaller one ; when thus arranged set fire to the moistened paper,
and when it has burned a second or two put the stopper in its
place; a very good vacuum is by this means formed, and the
process of dessication goes on rapidly. I have repeatedly used
this method, and found it succeed very well ; I think equally so
with that usually adopted by means of the air-pump ; although
by some it may be ridiculed in these days of elegance and refine-
ment.

The substance in this state is to be mixed with a portion of
the oxide recently ignited, but in this case suffered to cool, then
as quickly as possible introduced into the tube. As much of
the oxide may be used as would occupy an extent of tube equal
in proportion to that shown in fig. 5 ; a quantity of oxide is then
to be put upon the mixture, and over this it is sometimes well to
put a small quantity of copper filings or scrapings ; upon these
the asbestos is to be used as above, and the operation of igni-

174 Apparatus for the Analysis of Organic Products. [March,

tion is to be conducted in a somewhat different manner to that
last-mentioned.

The lamps in this case are to be lighted at the extremity next
the o-asometer, and as soon as the gas ceases to be liberated, the
next in succession may be employed, and so on to the end ; but
instead of suffering the whole of them to continue in flame, it is
as well to extinguish a portion, and to sutler only about three or
four to remain in operation at once, but taking care to ignite
the whole extent of tube at the close of the process. The
gaseous products being collected, and their bulk noticed, their
analysis is to be conducted in the usual manner, taking care,
however, in all instances, to observe the precise temperature of
the gases, that their bulk, as also the quantity of aqueous vapour
they contain, may be estimated,* and either to equalize the
internal and external surfaces of the mercury, or to calculate the
volume of gas by the difference of mercurial levels.

Description of the Plate.

Fi°\ 1, a a and b b, two long spirit lamps, each having ten
burners and wicks, the burners of each lamp sloping towards
those of the other, as seen in the end view, fig. 2 ; they are
placed in a tin tray, r c, mounted on four feet ; this tray is per-
forated in the middle the whole length of the lamps, and as wide
as e e, fi°\ 2 ; the object in making the burners sloping is, that
they may clear the lamps and approach each other as near as
requisite, and yet leave a clear current of air to the flames, and
the tray is perforated and mounted on feet to admit this current.

d d, are springing wires placed at each end of the tray to
receive the tubeff, which contains the substance to be analyzed,
and to hold it over or between the two rows of flames; by press-
ing the finger and thumb on the two shoulders, g g, fig. 2, the
wires open to receive the tube, and close on letting go ; and
should the tube be shorter than the lamps, an additional support
on a leaden foot, fig. 3, is placed through the opening e e of the
tray to rise between the flames, and hold the end of the tube ;
the tubes are hermetically sealed at one end, and the materials
then put in while the tube is straight ; it is then bent at the
other end to suit the mercurial trough.

The tubes are coated with copper foil, wrapped spirally round
them ; if each succeeding fold lie on half the other there will be
a double coat of copper all the way ; if it lie on two-thirds, there
will be three layers of copper, and so on ; by which the glass
tube is supported from bending when hot, and becomes very
uniformly heated. The spirals are continued beyond the end of
the tube, to reach the support, and leave the end within the
flames. The dotted lines at h, fig. 4, show the end of the tube,

« For which very convenient formulae will be found in the ninth edition of Dr.
Henry's Elements of Chemistry.

1824.] On (he Ancient Tin Trade. 175

short of the support ; the foil is secured at the last coil by bind-
ing wire, as at I.

Fig. 5 shows the foil in act of being wrapped on, also the pro-
portion of the space occupied by the materials ; first, the mixture
of oxide of copper with the material to be analyzed, next pure
oxide of copper, or copper filings ; and lastly, asbestos. When
the quantity of water formed is considerable, the tube is either
blown into a bulb, as at k, fig. 6, or melted on to one ready pre-
pared, as at /.

Fig. 7 is a long funnel, made by drawing out the end of a tube
of a suitable thickness at m, till it is long and small enough
through n n to reach to the bottom of the tube, and then cutting
it off at in, by which liquids maybe introduced to the bottom of
the tube without wetting the sides.

As the wicks nearest the trough are to be lit first, and the
remainder in succession, as the former finish their action, there
are upright supports of tin, o o, fixed on the lamps, one for each
space between the burners, against which to rest a slip of tin p p,
to prevent the lighted wicks from kindling those next, and it
also enables the experimenter to blow out those that have done
their duty. In fig. 2, the tin slip, p p, is shown by dotted lines,
reaching from lamp to lamp: little flat caps are put on each
burner when done with, to prevent the waste of spirit. Fig. 8
shows one of these caps, q, on its place ; rr, fig. 1, a shelf fixed
to the mercurial trough, to hold the lamps ; s s the graduated
jar. Tin pipes with corks, w w, as shown in fig. 2, are the
apertures to pour the spirit into the lamps ; their places only are
marked at w to, fig. 1.

Article IV.

On the Ancient Tin Trade, as described by the Rev. J. Hodgson.
(To the Editor of the Annals of Philosophy.)

SIR, IIucl For, Cor ii mi 11, Jan. 1, 1824.

One of the adventurers in our mine very obligingly lends me
the Annals of Philosophy, with which I am much amused in the
winter evenings. In No. 36, for December, 1823, there is a
paper " On the Era when Brass was used in Purposes to which
iron is now applied," by the Rev. J. Hodgson; and I find it
mentioned there, " that it is probable that the Egyptians or
Phoenicians had made mercantile voyages to this country " (the
land of the Britons) " more than lb centuries before that time"

ii. e. the time of Julius C*sar). " That it was known to the
Phoenicians in the time of Homer, his accounts of amber and
tin are unquestionable evidence." " And there can be no doubt

176 On the Ancient Tin Trade. [March,

but that the Greeks and Romans frequented it commonly ever
after the destruction of Carthage, if not sooner."

Now, Mr. Editor, this account of the tin trade induced me to
make some inquiries of the vicar of my parish, who gave me
permission to look at the books in his library ; so after my day's
work in the mine (of which, Mr. Editor, I am a captain), I had a
peep into Dr. Borlase's Natural History, and a few other works,
out in none of them can i find that the Egyptians or Phoeni-
cians were such great navigators at the period above mentioned,
i. e. about 1700 years before Christ.

In the 31st chapter of Numbers, verse 22, we are told that the
Israelites in their wars against the Midianites are directed to
keep for their own use the gold, the silver, the brass, the iron,
the tin, and the lead. If this country were then known, we
should feel much obliged to Mr. Hodgson, if he would tell us his
authority. Had this country been the only one in which tin was
ever found, it would certainly have been a strong ground for pre-
suming that the Phoenicians had traded here at the time of the
Trojan war. Tin was generally known in Spain,* and amber +
has been found in other places besides the Baltic. Therefore I
do not think that there is " unquestionable evidence" that it
was known to the Phoenicians in the time of Homer, about eight
centuries before Christ. Carthage, we know, was founded by a
colony from the Phoenicians nearly 900 years before Christ; and
other colonies were planted by them at Tangier, Malaga, Gades,
&c. Now, Sir, as I know very few of the old books, 1 should be
glad to be informed where I shall find any account of people
before that period venturing into the Atlantic. Where we are
left in darkness we may be allowed to reason from analogy.
When the Portuguese became acquainted with the use of the
compass about three centuries ago, what sort of voyages, and
what discoveries, did they make, on the coast of Africa, and how
easily were they deterred from prosecuting them by a storm.
Cape Non was for some time the extreme point to which they
ventured. Will it then be believed that the Phoenicians or
Egyptians were in the habit of trading to this country without
the aid of the needle 16-^- centuries before Christ. It may be in
the recollection of those who have read Robertson's America,
that a Portuguese in sailing for the Cape of Good Hope was
driven by the currents and winds out of his course, and unex-
pectedly discovered a part of South America. In the same way
do I believe that this country was first found ; for in those
days what navigator, however adventurous, would have quitted
the coast of Spain to explore unknown seas 1 If the trade in
tin by sea had been known for so many centuries, how does it
happen that Herodotus^ should have been perfectly ignorant of
the matter, and in his mention of tin points to the Eridanus,

• Pliny, lib. 34, c. 16. f Pliny, lib. 37, c. 3. i Thalia, Sect 115.

1824.] Mr. Dillwyn on Fossil Shells. 117

which he says has a Greek derivation. How comes it that we
have no accounts recorded of any voyages made to a great dist-
ance beyond the Straits of Gades much earlier than 600 years
before Christ. Then with respect to the Greeks trading here,
Camden says, that they came here 160 years before Csesar, and
Bochart fixes the period more than a century lower, 117 years
before Christ. These Greeks were adventurers whohad quitted
Samos with the intention of forming a colony on the coast of
Egypt, and were driven by a storm through the Straits, near
which place they settled. These were the only people of that
nation who traded with us. Nor after the destruction of Car-
thage do I believe that the Romans frequented this country, for
if they had done it, the spring tides would certainly have been
well known to Ceesar.*

I am not unacquainted with the account in Strabo, lib. 3, of
the Phoenician vessel being run on shore by the crew when pur-
sued by a "Roman. That could not possibly have taken place
until the conclusion of the first Punic war, and by that time, and
long before the trade in tin had been established across France
by the Marseiilois, a Greek colony, who had quitted Phoctea,
before Christ 539, and had carried on the trade in tin and amber
with the Romans, to which Herodotus points, and which is sub-
sequently detailed by Diodorus Siculus.

I trust, Sir, that you will allow these few observations to be
inserted in the Annals, solely with the view of drawing Mr.
Hodgson's attention to the subject, and with the hope that he
will kindly favour us with a paper " On the Tin Trade," in one
of your future numbers.

I am, Sir, your obedient servant,

A Tinner.

Article V.

On Fossil Shells. By Lewis Weston Dillwyn, Esq. FRS.f In a
Letter addressed to Sir Humphry Davy, Bart. Pres. RS.

As fossil shells are more numerous, and generally occur in a
better state of preservation than any other of the organic remains,
they have become one of the most interesting objects for geolo-
gical research, and there is such an exact conformity in the
structure ot'raanv of these fossils with the living genera, as to
render it in the highest degree probable, that the habits of their
animals were also similar. By availing ourselves of these ana-
logies, some circumstances attending the distribution of fossil

* hih. iv. sect. 9. + From the Philosophical Transactions for 182.J, Part II.

New Series, vol. vii. n

178 Mr. Dillwyn on Fossil Shells. [March,

shells may be observed which have hitherto escaped notice, and
if you should find them to be sufficiently interesting, or likely to
open a new door for inquiry, I beg that you will submit to the
Royal Society the following observations on the fossil remains of
the Molluscae.

Pliny, in describing the shell fish which was supposed to
yield the Tyrian die, has observed, ' lingua purpurae longitudine
digitali, qua pascitur perforando reliqua conchylia ; ' and
Lamarck says, that all those molluscse whose shells have a notch
or canal at the base of their apertures, are furnished with similar
powers, by means of a retractile proboscis ; and in his arrange-
ment of invertebral animals they form a section of the Tracheli-
podes, with the name of ' Zoophages.' Whether all these
Trachelipodes are possessed of the same predaceous powers of
boring into hard substances, and whether some of them may not
subsist chiefly on dead animals, my own observations have led
me greatly to doubt ; but this notch or canal is made for the
protrusion of a trunk, which is formed to answer the same pur-
poses as the respiratory organs of a Gastrobranchus,* and may
serve at once to distinguish a carnivorous species. The follow-
ing fossil genera belong to this section of the Trachelipodes —
Conus, Oliva, Ancilla, Terebellum, Seraphs, Cypnea, Ovula,
Volvaria, Marginella, Voluta, Mitra, Terebra, Buccinum, Harpa,
Monocerus, Purpura, Cassis, Cassidaria, Strombus, Rostellaria,
Triton, Murex, Ranella, Pyrula, Fusus, Cancellaria, Potamides,
and Cerithium.

In all the other genera of turbinated univalves, the lower mar-
gin of the aperture, instead of being either notched or chan-
nelled, is entire ; and Adanson, in his History of Senegal, so fin-
back as 1757, has shown that the Molluscee of these shells have
jaws which are formed for feeding on vegetable substances ; and
they have been proved, by subsequent observations, to be
entirely herbivorous, i. e. the marine genera feed on algae, and
the fresh water and land <;enera on the leaves of vegetables.
These together constitute the other section of the Trachelipo-
des, which Lamarck has called ' Phyti phages,' and it comprises
the following genera of fossils — Turritella, Turbo, Cirrus, Euom-
phalus, Trochus, Solarium, Delphinula, Scalaria, Natica, jVerita,
Ampullaria, Vivipara,+ Paludina, Melania, Planorbis, Cyclos-
toma, Auricula, Tornatella, Bulimus, Helicina, and Helix.

Every turbinated univalve of the older beds from transition
lime to the lias, which I have been able to procure, or of which
I can find any record, belongs to these herbivorous genera, and
the family has been handed down through all the successive

• See Sir E. Home's observations on this animal under the name of Myxine, in the
Philosophical Transactions for 1815, p. 261.

■f I am unable to distinguish this genus from Paludina ; and the name of Vivipar* is
calculated to mislead, for none of the specie* are more than ovi- viviparous.

1824.] Mr. Dillwyn on Fossil Shells. 179

strata, and still inhabits our land and waters. On the other
hand, all the carnivorous genera abound in the strata above the
chalk, but are comparatively extremely rare in the secondary
strata, and not a single shell has been detected in any older bed
than the lower oolite. As a proof of this rarity it may be
remarked, in the list of British fossils which Mr. Parkinson has
given in his Introduction to the Study of Organic Remains, that
not one single species of either of the carnivorous genera has
been referred to any stratum below the London clay, and only
the few following species appear in any of the numerous lists of
the secondary strata which are given in Conybeare and Phillips's
Outlines of Geology, viz. a Murex* and Pleurotoma rostrata in
the green sand, Ceritldum melanoides in chalk marie, and a few
species of Rostellaria in various strata from chalk marie to the
lower oolite. For the Pleurotoma and the Cerithium, a refer-
ence to the Mineral Conchology is given ; and Mr. Sowerby
there only says that he has seen an imperfect cast, very like the
former, from the canal at Devizes ; and of the latter, that it was
found in, the London clay, and in the clay above the chalk at
Newhaven. It is also worthy of remark, that all the above-
mentioned Rostellariae which have been found in secondary
strata are nearly allied to the Linncean Strornbus Pes Pelecani ;
and it may be observed that this species, when fully grown, has
not any open canal at its base ; and that in the figure which
Muller has given of the animal there is no appearance, nor in
Montagu's description is any mention made, of that retractile
proboscis or respiratory trunk, which are the distinguishing cha-
racters of a carnivorous Trachelipode. I therefore propose to
remove these Rostellariae of the secondary strata, which are
readily distinguished by the remarkable expansion of their outer
lips, to form a separate genus with Petiver's name of Aporrhais
and the other fossil Rostellariae which have the recent Strornbus
Jissus, for their type are only to be found in strata above the
chalk.

Small circular holes, which have been bored by the predaceous
Trachelipodes, are frequently found in recent shells, and I have
seen exactly similar holes in many fossils, but they have all been
taken from the London clay or crag ; nor have 1 been able to
find any such appearance in any fossil of the older formations.
If this observation should be confirmed by a more extended
examination of other cabinets, it will prove that neither the
Aporrhaides, or any of those few undoubtedly carnivorous species
which have been found in the secondary formations, were fur-
nished with any such predaceous powers as Pliny has described,
and that they belong to a subdivision of the Trachelipoda zoo-

" Mr. George Sowerby has sent uiethis shell with the name of Murrx calcar, anil if
I am not much mistaken, I have seen another species of Murex from the grccu band in
the extensive collection of Mr. J. S. Miller.

N 2

180 Mr. Dilhn/n on Fossil Shells. [March,

phaga, which feed only on dead animals. Without attempting
to distinguish the more predaceous from these other genera, I
shall however at present content myself with proving, and for
this I have adduced sufficient evidence, that the whole family of
the carnivorous Trachelipodes are extremely rare in all those
strata where the Ammonites and other Nautilida? abound.

In describing the Ammonites, De Montfort, in his Conchologie
Systematique, observes, that they are found of all sizes, " depuis
la grandeur d'une Lentille jusqu'a celle de 8 pieds de diametre;"
and, as a proof of their great abundance, Lamarck says, " La
route d'Auxerre a Avalon, en Bourgogne, est fence avec des
Comes d' Amnion." These Ammonites, as well as most of the
other principal multilocular genera, appear to have become
extinct in our northern latitudes when the chalk formation was
completed ; but a few of the Nautilidte still inhabit the southern
ocean, and their niolluscae belong to the carnivorous order
which Lamarck has described under the name of Cephalopodes.
From the occurrence in such great numbers of the carnivorous
Trachelipodes in the formation above the chalk, it therefore
appears, that the vast and sudden decrease of one predaceous
tribe has been provided for by the new creation of many genera,
and a myriad of species possessed of similar appetencies, and
yet formed for obtaining their prey by habits entirely different
from those of the Cephalopodes.

It may be further observed, that all the marine genera of the
herbivorous Trachelipodes to which either of the fossil species
belongs, are furnished with an operculum, and that the few car-
nivorous species which have been found in the secondary strata,
agree with them in this particular, although the unoperculated
genera are very abundant in the London clay. Lamarck, of the
fresh water Trachelipodes says, that those which are not fur-
nished with an operculum are formed for the occasional respira-
tion of air; but i believe that this observation is not applicable
to the marine genera; and it was Adanson's opinion, that the
operculum is intended for the protection of the animal; nor can
I imagine any thing against which such a shield would be more
necessary than the long and pliable fingers of the Cephalopodes,
when they abounded in the seas, as they must formerly have
done. It is, therefore, at least a curious coincidence, that ail the
marine Trachelipodes of the transition and secondary strata, of
which I can find any record, belong to genera which are
furnished with an operculum, and that none of the numerous
unoperculated genera should have been found in any other than
the tertiary formations where the Ammonites disappear. For
the protection of the testaceous Gasteropodes no such shield
would be wanting, and including this order it may be generally
observed, that none of the marine unoperculated Molluscs,
except the Cephalopodes, are to be found in the lias, or in any of

1824.] Active Potter of Dilatation of the Heart. 181

its older strata ; and it appears to me that a much greater
approach towards the same variety of testaceous animals which
now inhabits our seas is to be found in the adjoining bed of
lower oolite.

The foregoing observations are confined chiefly to British
fossils ; for as a few of the testaceous Cephalopodes still live in
the warmer climates, it is possible that the Ammonites, as well
as some others of the extinct genera, may have existed longer,
and that their remains may be found in the tertiary formations
of the more southern latitudes. Although fossil Nautilidae are
common in the secondary strata of the United States, they are
said not to have been found in South America; and it may,
therefore, be queried whether the Cephalopodes were not con-
fined to the more northern latitudes when the chalk formation
was completed, and whether a decrease in the earth's tempera-
ture at that period may not have occasioned the entire destruc-
tion of some genera, and a migration of others to the southward.

It is highly probable, when a more perfect knowledge of the
testaceous animals has been obtained, that the line of inquiry
which I have now suggested may be greatly extended, and the
collected tendency of such analogies between the habits of living
animals and the organic remains of the different strata, may
serve to throw some light on the nature of the changes which
the surface of our planet has undergone.

Article VI.

On the active Power of Dilatation of the Heart*
By David Williams, M.D.

(To the Editor of the Annah of Philosophy.)

DEAR .SIR, Liverpool, Feb. 7, 1824.

The following observations were made during my experiments
on the practicability of an operation for phthisis pulmonalis/|-
and also while inquiring into the cause and the effects of an
obstruction of the blood in the lungs.'!' By securing the trachea
of an animal at the acme of inspiration, the heart continues its
action for some time. To ascertain the strength of the active
power of dilatation attributed to the right auricle and ventricle,

* Extracted from An Essay on the Motive Powers of the Circulation of the Blooil,
read before the Literary and Philosophical Society of Liverpool, Jan. 182 1.
■f Annul* for June.
\ Anmih for September.

182 Dr. Williams on the active Power [March,

the cavsfe were compressed, the inferior as near the diaphragm
as possible, and the superior, a little above its entrance into the
auricle. As the auricle was thus suddenly limited to the small
quantity of blood, that the vena azygos and the coronary veins
poured into it, it was expected that the blood, which remained
in the inferior cava between the compressed part and the auricle
would have been pumped out ; but no effect indicating a sudden
extraction of blood from the isolated portion of the inferior cava
could be perceived. Had the auricle or ventricle exercised the
function of active dilatation, it must have been discovered, for
the lungs were quiescent, and no muscular action, save that of
the heart itself, perplexed the observation. After the last systole
of the left ventricle has occurred, irregular and hurried, or flut-
tering contractions of the muscular fibres of the right ventricle take
place. When they have ceased, the right ventricle feels full and
soft, and the left feels contracted or collapsed. If now we open
one of the pulmonary veins near their termination in the auricle,
no expansion of the latter chamber or of the ventricle will take
place ; but as the residue of the blood in the pulmonary veins
drains into the ventricle, it imperceptibly fills, and its walls feel
softer to the touch.

We shall now take into consideration the influence ascribed
to the active power of dilatation of the heart in the economy of
the circulation. In the first place, we shall inquire into the
nature of the power ; then compare its characteristic qualities
with the above phenomena ; afterwards we shall be able to
judge whether we have arrived at any facts capable of furthering
our acquaintance with the moving powers of the circulation. As
Dr. Wdson Philip is the last author on our subject whose writ-
ings I have perused, I shall take the liberty of quoting the fol-
lowing periods from his valuable essay,* so as to give my
leaders a correct statement of the ideas entertained by Dr.
Philip, as to the nature and the influence exercised by the inhe-
rent dilating power of the heart, and also the resilience of the
lungs. " What purpose then/' says Dr. Philip, " is served by
the dilating power of the ventricles increased by the tendency of
the lungs to collapse ? It favours the entrance of the blood sud-
denly propelled into it by the contraction of the auricle ; and
the degree of dilating power is well proportioned to this office.
Without this dilating power, the tendency of the ventricle would
be to remain in a state of collapse after the systole, and part of
the power of the auricle would be expended in dilating the ven-
tricle. Here, as in many other instances, both in man and the
inferior animals, we see nature saving the muscular by the sub-
stitution of the elastic power." In the last sentence we perceive
Dr. Philip recognizing elasticity to be the nature of the inherent

" Some Observation* relating to the Powers of Circulation, &c. Medico-Chir. Trans.
Vol. xii. Part. II.

1 824.] of Dilatation of the Heart. 1 83

power which enables the ventricles to dilate themselves. Pray
what is the nature of the action of an elastic body ? Mr. John
Hunter thus defines it : " The action of elasticity is continual,
and its immediate effects are produced whenever the resistance
is removed ; by which it may be distinguished from other
powers." * From our definition, we learn that the action of an
elastic body is permanent, and that as soon as the resisting
power which retains it in a forced position is removed, that it
immediately regains its natural state of rest. In order to the
elucidation of our problem, we shall admit the body of the left
ventricle of the heart to be possessed of an elastic property. As
the systole of the ventricle throws the elastic property into a
forced position, and as the ventricle remains for some time after
its last systole in a comparative state of collapse, we have only
to do away with the influence of the power which retains it
during that period in that state, and the elastic property will
instantly restore itself to its natural position. Before we set
about releasing it from its constrained situation, we shall inquire
into the nature of the power which we have to contend with.
Asa state of relaxation in a muscular fibre succeeds the state of
contraction, it follows that the action of the muscular fibres of
the walls of the ventricle cannot be the cause of the confinement
of the elastic property in its unnatural position, for we admit
contraction to be the last motion of the ventricle. The resisting
power then must arise from the propulsion of a portion of the
blood into the aorta from the cavity of the ventricle by its sys-
tole, without its being able (by its elasticity or active power of
dilatation) to draw its wonted supply in return from the auricle,
on account of the latter being itself deprived of its usual supply.
Therefore, as the elastic property endeavours by its reaction to
regain its natural state of rest, a tendency to form a vacuum in
the cavity of the ventricle must be the result, which effectually
retains the elastic property in its constrained position. Now if
we can establish a communication between the cavity of the
ventricle and the exterior air, it is evident that we shall do
away with the tendency to a vacuum, and consequently with the
resistance offered to the reaction of the elastic property. Such
a communication is easily established without, doing any injury
to the walls of the ventricle, by opening one of the pulmonary
veins, near their junction with the auricle. In the narration of
our experimental investigation, we are informed that after such
an expedient was had recourse to, that no such phenomenon as
dilatation of the ventricle was remarked. Therefore if we can
depend on the correctness of the observations during the above
experiments, and if observations under such circumstances can
be relied on, we must conclude the active power of dilatation, or

* On the Blood.

184 Active Power of Dilatation of the Heart. [March,

the action of the elastic property of the auricles and ventricles,
to be either ideal, or to be so extremely feeble, as to be capable
of evading our senses under the most favourable situation in
which we can place the organs for inspection. For I can
scarcely conceive it possible to devise more decisive modes of
ascertaining the existence of such a power, though ever so
trifling, than those had recourse to.

Further, as the action of an elastic substance is as perfect
after the extinction of life, until the process of putrefaction
destroys its texture, as during the existence of the animal ; by
examining a heart detached, after its absolute death, or after
its utmost contraction by the vis mortua, we can readily
satisfy ourselves, whether the walls of the ventricles have
any elastic property that can be appreciated. If we find a heart
contracted, and on pressing its body so as to flatten it, that it
does not present to our senses a disposition to recover its natural
shape similar to what we witness in the truly elastic arteries
whose roots are attached to its base, what inference are we to
draw? Why certainly we must need infer that it possesses no
greater elastic property than muscles in common. The condition
of the heart greatly depends on the state of the animal when
killed. Fat beasts (more particularly sheep), from their un-
wieldiness, and from the action of their diaphragms being
restrained by their obesity, are easily overdriven, and sometimes
on their way to the slaughter-house, to prevent their suffocating,
they are obliged to be " stuck; " or from urgency, they are killed
while yet breathless and ready to faint. The right ventricle of
the heart of an animal killed in such a plight is found to be
gorged, and the reason appears to me to be obvious. As the
blood is more or less obstructed in its passage through the
lungs, previous to the sticking of the animal, the pulmonary
artery and the cavities of the right side of the heart are necessa-
rily more or less gorged, and the ventricle and pulmonary artery
must remain so ; for during the time the animal is bleeding to
death, a small portion only of the blood which they contain at
the time the animal is stabbed, can pass into the system of the
pulmonary veins, for want of pure air in the air cells of the lungs
to enable it to undergo the mysterious change in the rete Mal-
pighii. Thus the right ventricle will be large and flabby, or
with its muscular fibres relaxed after the pluck is extracted ; for
in consequence of its being retained in a state of extension, the
action of the vis mortua is prevented from affecting its muscular
fibres. When an animal is killed by dividing the blood-vessels
of the neck without any previous obstruction in the lungs, then
no engorgement can take place in the right ventricle, for the
blood rushes with unusual impetuosity towards the point where
there is the least resistance, and in a few minutes nearly the
whole of the blood in the body escapes through the artificial out-

1824.] Table of Equivalent Numbers. 185

lets. I think the. gorged state of the right ventricle of the heart
of an. animal when killed, while breathless and. faint, to be
another evidence in support of my opinion, that prostration of
strength, arising from short continuance of anxious exertion, is
the immediate effect of an obstruction of blood in the luno - s. #

Article VII.

-4 Table of Equivalent Numbers.

[Since the publication of any table of equivalents in the Annals,
various important additions have been made to this department
of chemistry ; new editions of Dr. Thomson's and of Dr. Henry's
treatises on chemistry have appeared, and Mr. Brande has pub-
lished a table in the Institution Journal. In the present table, I
have inserted corrections obtained from various sources, and
a few as the results of my own experiments. — Edit.]

ACID, acetic

crystallized ( 1 water)
arsenic
arsenious
benzoic
boracic ? • .

crystallized (2 water)
carbonic . ,

chloric

chloriodic .
chlorocarbonic ' .
chlorocyanic
chromic . ' .

citric

crystallized (2 water)
columhic ?
fenocyanic. .
fluoboric ?
fluoric
formic
fluosilicic
gallic ?
hydriodic
hydrocyanic .
hydrofluoric .
hyposulphurous .
hyposulphuric

TABLE I.

Acid, iodic
malic
molybdie
molybdous
muriatic

50
.59
62
54

120
22
40
22
76

161
50
62
52
58
76

152
?
22
17
37
24
63

126
27
17
24
36

nitric (dry) .
liquid (sp. gr. 1-50 2 water)

nitrous

oxalic

crystallized (4 water)

perchloric

phosphoric .

phosphorous .

suclactic

succinic (anhydrous crystal:

sulphuric (dry)

liquid (sp. gr. 1*483S)

sulphurous .

tartaric

crystallized (I water)

tungstic

uric
Alum (dry) .

(crystallized 25 water)
Alumina . . .

sulphate .

subsulphate (2 acid, 3 base)

165
70
72
64
37
54
72
46
36
72
92
28
20

105
50
40
49
32
67
7C

120

45?

262

487
27
67

116

• Medical and Surgical Journal for Oct. 1823, p. 535.

186

Table of Equh

ahnt Numbers. [Ma

Aluminum .

19

benzoate . .

Ammonia •

n

borate

acetate

67

carbonate . .

bicarbonate (5

I water) . 79

chlorate . • i

borate ? (dry)

39

eliminate

crystallia

ed (2 water) . 57

citrate

carbonate

39

hydrate . . .

sesquicarbona

te (2 water) . 118

iodate . . .

citrate .

75

nitrate

fluoborate

39

muriate (cryst. 1 water)

hydriodate .

. 143

oxalate

iodate

. 182

phosphate .

molybdate .

89

phosphite

muriate •

54

succinate . .

nitrate .

71

sulphate . . .

oxalate .

53

sulphite

(cryst.

1 water) . 62

tartrate . , .

phosphate

45

tungstate . . .

phosphite

37

Benzoic acid . . .

succinate

67

Bicarburetted hydrogen .

sulphate .

57

Bismuth

sulphite

49

acetate

tartrate

84

arseniate . . .

potassa-tartra

te . . 208

benzoate

Antimony

44

chloride

chloride

80

citrate

iodide

. 1G9

iodate . , .

deutoxide

56

icdide . .

peroxide

GO

nitrate . .

protoxide

52

oxalate . .

sulphuret

60

oxide

potassa-tartra

te . . ?

phosphate

Arseniate of aram

ania . • 79

phosphuret . .

potash

. 110

sulphate

soda

94

sulphuret . . .

Arsenic .

38

tartrate

acid

63

Boracic acid

chloride

?

acid crystallized (2 water)

iodide

?

Borax (8 water) .

Arsenious acid

54

Boron .

Azote . .

14

Cadmium

Barium .

70

carbonate . . .

chloride

.106

chloride . . .

iodide

195

iodide

peroxide

86

nitrate .

phosphuret

82

oxide

sulphuret

86

phosphate

Barytes

78

phosphuret . . .

acetate

. 128

sulphate

arseniate

. 140

sulphuret . . .

arsenite

. 132

Calcium . . .

1824.} Table of Equivalent Numbers.

187

chloride

56

binacetate

. 180

fluoride

36

cryst. (3 water, dist. verdigris) 207

iodide

. 145

subacetate ( 1 acid 2 base)

. 210

oxide (lime)

28

carbonate (unhydrous) .

. 102

phosphuret .

32

(2 water, malachite)

. Ill

sulphuret

36

iodide

189

Calomel .

. 236

perchloride ,

. 136

Camphoric acid . ,

?

pernitrate

. 188

Carbon .

6

persulphate .

. 160

perchloride

. 120

crystallized (10 water)

. 250

protochloride. .

42

perphosphate

136

subchloride

48

phosphuret .

76

hydrochloride

50

protochloride

. 100

oxide

14

protoxide

72

phosphuret .

18

peroxide

SO

sulphuret

38

sulphuret

80

Carbonic acid

22

Corrosive sublimate

. 272

oxide

14

Cyanogen

26

Carburet of azote.

26

Fluorine .

16

sulphur . .

38

Glucina

26

phosphorus .

IS

Gluciuura

18

Carburetted hydrogen

8

Gold

. 200

Cerium ....

46?

chloride

. 236

Chloric acid . .

76

iodide

. 325

Chlorine

36

protoxide . . 1 +

1=208

Chromium

28

peroxide . . 1 +

3 = 224

deutoxide

44

sulphuret . . 1+3 = 248

oxide . .

36

chloride of, & sodium (dry)

296

Cobalt .

26

crystallized, 8 water

368

acetate

84

Hydrogen

I

arseniate

96

Iodine .

125

benzoate

154

Iron ....

28

borate . . ,

56

protochloride

64

carbonate . . ,

56

perchloride

82

chloride . .

62

peroxide

40

citrate . . .

92

protoxide

36

iodide

151

sulphate (dry)

76

nitrate . .

SS

crystallized (7 water)

139

oxalate . . .

70

persulphuret

60

peroxide

?

protosulphuret

44

phosphate

68

Lead ....

104

phosphuret .

38

acetate

162

protoxide

34

crystallized (3 water)

189

sulphate (dry) . .

74

sub-binacetate . .

274

crystallized (7 water)

137

sub-tritacetate

386

sulphuret

42

arseniate . . .

174

tartrate .

101

benzoate . .

232

Columbium

144?

borate . .

134

Copper ....

64

carbonate

134

acetate ...

130

chlorate

188

cryst.(C water. Com veriligr

s) 184

chloride

140

188 Table of Equivalent Numbers.

[Ma

chiomate

164

Magnesia . . .

citrate . . •

no

ammonia-phosphate .

deutoxide

116

borate ? .

iodate . . .

277

carbonate

iodide . . .

229

hydrate

malate

182

muriate . .

molybdate

1S4

nitrate . .

nitrate . .

166

phosphate

oxalate ...

148

sulphate (dry)

peroxide . .

120

crystallized (7 wat<

*)

phosphate . . .

140

tartrate

phosphite . . .

132

Magnesium

phosphuret . . .

116

chloride .

protoxide

112

iodide .

succinate

162

phosphuret . .

sulphate

152

sulphuret . .

sulphite

144

Manganese

sulphuret . . .

120

acetate

tartrate . . •

179

benzoate

Lime ....

28

carbonate

acetate

78

chlorate

arseniate

90

chloride

benzoate

148

citrate . ,

biphosphate .

84

deutoxide

borate . . •

50?

oxalate

carbonate

50

peroxide

chlorate

104

phosphate

chloride

64

phosphuret .

citrate . .

86

protoxide .

chromate

80

succinate

hydrate

37

sulphate

iodate

193

tartrate

muriate cryst. (5 water)

. 110

Mercury

oxalate . .

64

hipersulphate

phosphate . .

56

bisulphuret .

phosphite . .

48

bicyanuret .

succinate

78

pcrchloride .

sulphate

68

periodide . •

crystallized (2 water)

86

pcrnitrate

sulphite

60

peroxide

tartrate

95

perphosphate

tungstate

. 148

persulphate ,

Lithia

IS

protochloride.

carbonate

40

protonitrate .

nitrate . ,

72

protosulphate

phosphate

46

protoxide

sulphate

58

Molybdenum

Lithium

10

protoxide

chloride

46

Nickel .

iodide . ,

. 135

acetate

sulphuiet .

26

arseniate

1824.]

Table of Equivalent Numbers.

189

benzoate

. 157

borate

70?

borate .

59

carbonate

70

carbonate

59

chlorate

124

chloride

65

chromate . .-. ■

100

citrate .

95

citrate . . ,

106

iodide

. 154

hydrate

57

nitrate .

91

iodatc

213

oxalate

73

molybdate .

120

peroxide . .

, J>

nitrate . .

102

phosphate

65

oxalate

84

phosphuret

41

phosphate

76

protoxide

37

quadroxalate.

. 192

sulphate (dry

) . . 77

succinate

98

crystallizer

1 (7 water) . 140

sulphate

88

sulphuret

45

sulphite .

80

tartrate ,

. 104

tartrate

115

Nitric oxide

30

tungstate

16S

Nitrogen

14

Potassium

40

Nitrous oxide

22

chloride

76

Olefiant gas

7

iodide

165

Osmium

?

peroxide

64

oxide

?

phosphuret .

52

Oxygen .

8

protoxide (dry)

48

Palladium

?

sulphuret .

56

oxide ,

y

Rhodium

44?

Phosphorus

12

peroxide . .

60

carburet

IS

protoxide

52?

chloride

48

Selenium ? . .

41

perchloride

84

Silica

16

sulphuret

28

Silicium .

8

Platinum

96

Silver

. 110

ammonia-mu

riate . .196

acetate . .

168

perchloride

. 142

arseniate

. 180

peroxide

. 1)2

arsenite

. 172

bi-phosphure

t .120

benzoate

. 238

bi-sulphuret

. 128

borate ?

140

Potash (dry)

48

carbonate

. 140

acetate

98

chlorate

. 194

arseniate

. 110

chloride

. 146

arsenite

102

chromate

. 170

benzoate

. 168

citrate

176

bicarbonate

92

iodate

. 283

crystallizct

1(1 water) . 101

iodide . .

. 235

bichromate

152

molybdate .

. 190

binarseniate

172

nitrate

172

binoxalate

120

oxalate

. 154

biphesphate

. 104

oxide . .

118

bisulphate

. 128

phosphate

146

crystallize<

1(1 water) . 137

sulphate

158

bitartrate

. 182

sulphite

. 150

crystullizti

1 (1 water) . 191

sulphuret .

. 120

190

Table of Equivalent Numbers, [March,

tartrate

. 185

Sulphur .

16

tungstate

. 238

carburet . . .

38

Soda

32

chloride

52

acetate .

82

iodide

141

crystallized

(6 water) . 136

phosphuret .

28

arseniate

94

Sulphuretted hydrogen

17

arsenite .

86

Tannin? . . .

71

benzoate

152

Tellurium . . ,

38

bicarbonate .

76

chloride

74

borate ?

. 54

oxide

46

carbonate (dr

Y) •" • 54

Tin

58

crystallized

(11 water) . 153

bisulphuret . .

90

chlorate

. 10S

iodide

183

cbromate

84

peroxide . .

74

citrate

90

protoxide . . •

66

hydrate

41

perchloride . . .

130

iodate

. 197

protochloride

94

vnolybdate .

. 104

sulphuret . . ,

74

nitrate

86

phosphuret .

70

oxalate .

68

Titanium .

f

succinate

82

Tungsten . . .

96

sulphate (dry

) . .72

Tungstic acid

120

crystallizec

(10 water) . 162

Uranium

?

sulphite

64

oxide

y

tartrate

99

Uric acid • . «

45?

and potash

. 214

Water .

9

Sodium .

24

Yttria

40

chloride

60

Yttrium ?

32

iodide .

. 149

Zinc

34

phosphuret .

36

acetate

92

peroxide

36

arseniate . .

. 101

protoxide

32

benzoate

16S

sulphuret

40

borate

64

Starch ?

. 142

carbonate .

64

Strontia

52

chlorate

. us

acetate

102

chloride

7C

borate ?

74

citrate

. 10(

carbonate

74

iodate

. 201

citrate

110

iodide

, 15£

hydrate

61

nitrate .

9(

muriate (crys

t. 5 water) . 134

oxalate

7*

oxalate

88

oxide . .

48

phosphate

80

phosphate . .

W

sulphate

92

phosphuret . .

4(

tartrate

. 119

succinate . .

95

Strontium

44

sulphate (dry)

Si

chloride

80

crystallized (6 water)

. 13<

iodide

. 169

sulphite . .

7-

phosphuret

56

tartrate

. IK

sulphuret

60

Zirconia .

. 45

Sugar

. ?

Zirconium . .

. 37

1824.]

Table of Equivalent Numbers.

191

Hydrogen

Carbon

Boron ?

Bicarburetted hydrogen

Oxygen

Silicium .

Carburetted hydrogen

Water

Lithium

Magnesium

Phosphorus

Phosphuretted hydrogen

Nitrogen

Carbonic oxide .

Bihydroguret of phosphorus

Sulphur .
2 Oxygen.
Silica
Fluorine .

Ammonia

Sulphuretted hydrogen

Hydrofluoric acid

Alumium

Lithia

Phosphuret of carbon

Glucinum

2 Water
Aluminum

Phosphorous acid.

Magnesia

Calcium

Carbonic acid

Nitrous oxide

Horacic acid ?

Fluoboric acid ? .

Sodium .

Phosphuret of magnesium.

3 Oxygen

Hyposulphurous acid
Fluosilicic acid

Glucina .
Alumina .

Cyanogen

Sulphuret of lithium
Cobalt •

TABLE I

1

9
10

12

13

14
16
17

> 18

19

20

22

21

26

Hydrocyanic acid.

3 Water .

Sulphuret of magnesium
Alumica

Lime

Phosphoric acid .

Phosphuret of sulphur

Iron

Manganese

Chromium

Hydrate of magnesia
Nickel .

Nitric oxide

Sulphurous acid .

Soda

Phosphuret of calcium

Yttrium ?

4 Oxygen

Protoxide of cobalt
Zinc

Chlorine

Hyposulphuric acid
Protoxide of iron ,

— — manganese

chromium

Peroxide of sodium
Phosphuret of sodium
Sulphuret of calcium
Fluoride of calcium
Oxalic acid (dry)
Water .

Muriatic acid
Phosphite of ammonia
Protoxide of nickel
Hydrate of lime .
Zirconium ?
Formic acid

Sulphuret of carbon
Arsenic .
Tellurium

Borate of ammonia ? (dry)
Fluoboratc of ammonia ? .

27

> 28

29

30

> 32

31

> 36

!- 37

■ iss

39

192

Boracic acid (crystallized

Sulphuric acid

Potassium

Yttria ?

Sulphuret of sodium

Carbonate of lithia

Deutoxide of manganese

Peroxide of iron .

Phosphuret of manganese

Phosphuret of iron

5 Oxygen

Hydrate of soda .
Phosphuret of nickel
Selenium ?

Protochloride of carbon
Oxide of zinc
Carbonate of magnesia
Borate of magnesia ?
Sulphuret of cobalt

Protoxide of chlorine

Strontium

Peroxide of manganese

Deutoxide of Chromium

Rhodium ?

Protosulphuret of iron

Antimony

Phosphate of ammonia
Zirconia ?
Sulphuret of nickel
Uric acid ?

5 Water

Nitrous acid
Chloride of lithium
Phosphate of lithia
Phosphuret of zinc
Oxide of tellurium
Cerium ?

Protochloride of phosphor
Potash (dry)
Phosphate of magnesia
Subchloride of carbon
Molybdenum ? .
Chloride, of magnesium
Phosphite of lime ?

6 Oxygen

1

Sulphite of ammonia

Liquid sulphuric acid (I water)

} 40

}

41

V. 4*

Table of Equivalent Numbers.

Hydrochloride of carbon
Carbonate of lime
Borate of lime
Acetic acid
Sulphuret of zinc.
Succinic acid?
Chlorecarbonic acid
Chloride of sulphur
Protoxide of rhodium
Phosphuret of potassium
Protoxide of antimony
Strontia .
Chromic acid
Oxalate of ammonia
Dry nitric acid .
Muriate of ammonia
Carbonate of soda
Protoxide of cerium
Arsenious acid .

6 Water .

Sulphuret of potassium
Deutoxide of antimony
Chloride of calcium
Phosphate of lime
Phosphuret of strontium
Protoxide of molybdenum
Carbonate of cobalt
Borate of cobalt ?
Cadmium

7 Oxygen

Sulphate of ammonia

Hydrate of pctash

Borate of ammonia (2 water)

Muriate of magnesia

Tin

Cabonate of manganese

Sulphate of lithia

Citric acid (dry) .

Borate of nickel ?

Acetic acid crystallized

Carbonate of nickel

Chloride of sodium
Persulphuret of iron
Peroxide of rhodium
Phosphate of soda
Sulphate of lime
Sulphate of magnesia (dry)
Sulphuret of antimony
Peroxide of antimony

[March,

y 4i

1

45

> 46

>■ 48

49

1824.]

Hydrate of strorjtia
Phosphate of cobalt
Chloride of cobalt
Arsenic acid .
Chlorocyanic acid
Oxalate of ammonia ( 1 water)

Gallic acid .

7 Water .

Peroxide of potassium
Sulphite of soda .
Chloride of manganese
Protochloride of iron
Oxide of cadmium
Copper .
Molybdous acid .
Sulphuret of molybdenum
Phosphate of manganese
Chloride of lime .

8 Oxygen
Carbonate of zinc
Borate of zinc ? .
Oxalate of lime .

Chloride of nickel
Phosphate of nickel

Protoxide of tin
Sulphate of alumina

Sulphate of alumina
Tartaric acid (dry)
Acetate of ammonia
Succinate of ammonia
Ferrocyanic acid

Peroxide of chlorine
Sulphate of lime
Phosphuret of cadmium ?
Oxalate of soda .

Carbonate of potash
Borate of potash ?
Oxalate of cobalt
Chloride of zinc .
Phosphate of zinc
Barium .
Acetate of magnesia
Phosphuret of tin
Malic acid

Nitrate of ammonia
Tannin ?

New Series, vol. vii.

Table of Equivalent Numbers.

193

61

62

63

y 64

65

66

72

73

>• 74

Liquid nitric acid (2 water)

Crystallized oxalic acid (4 water)

8 Water .

Sulphate of soda (dry)

Nitrate of lithia

Protoxide of copper

Oxalate of manganese

Bismuth

Molybdic acid

Sulphuret of cadmium

Carbonate of strontia

Borate of strontia ?

9 Oxygen

Oxalate of nickel

Nitrate of magnesia
Sulphuret of tin .
Peroxide of tin .
Sulphite of zinc .
Sulphate of cobalt (dry)
Chloride of tellurium

Citrate of ammonia . . 75

Chloric acid

Crystallized citric acid (2 water)
Crystallized tartaric acid ( I water)
Chloride of potassium
Phosphate of potash
Phosphuret of copper
Bi-carbonate of soda (dry)
J> 67 Protosulphate of manganese
iron (dry)

Sulphate of nickel (dry) .

Baryta . . .

68 Acetate of lime . .

Succinate of lime .

: Arseniate of ammonia
j Bi-carbonate of ammonia (2 water)
Oxalate of zinc .

70

71

Sulphite of potash
Oxide of bismuth
10 Oxygen # .

Peroxide of copper
Protosulphuret of copper
Chromate of lime.
Phosphate of strontia
Chloride of strontium

> 76

J

77

78

79

> 80

O

194

Chloride of antimony
Sugar ? . .

Nitrate of lime
Phosphuret of barium
Perchloride of iron
Sulphate of zinc (dry)
Acetate of soda .
Succinate of soda .

Bi-chloride of phosphorus
Phosphuret of bismuth
Bi-phosphate of lime
Chromate of soda .
Acetate of cobalt .
Oxalate of potash
Tartrate of ammonia

Arsenite of soda .

Sulphate of lime cryst. (2 water)

Carbonate of cadmium

Acetate of manganese

Succinate of manganese

Peroxide of barium

Sulphuret of barium

Nitrate of soda

Citrate of lime

Acetate of iron .

Hydrated baryta .

Acetate of nickel .

Tartrate of magnesia

Sulphate of potash

Sulphuret of bismuth

Nitrate of cobalt .

Oxalate of strontia

1 1 Oxygen

Molybdate of ammonia

Arseniate of lime.

10 Water.

Nitrate of manganese

Bi-sulphuret cf tin

Protonitrate of iron

Citrate of soda '.

Nitrate of nickel •

Perchloric acid .
Bi-cv.rbonate of potash (dry)
Chloride of cadmium
Citrate of cobalt .
Phosphate of cadmium
Sulphate of strontia
Acetate of zinc .
Succinate of zing •

Table of Equivalent Numbers. [M

Chlorate of ammonia

1

\

81

82

64

" 86

87

88

89

). 90

91

> 92

Ammonia-phosphate of magnesia

Citrate of manganese
Protochloride of tin
Arseniate of soda .

Tartrate of lime .
Citrate of nickel .

Arseniate of nickel
Platinum
Nitrate of zinc .
Tungsten ?
12 Oxygen

Succinate of potash
Acetate of potash .
Phosphite of baryta

Tartrate of soda .
Arseniate of nickel
11 Water

Carbonate of barytcs
Borate of barytes ?
Persulphate of iron
Citrate of zinc
Protochloride of copper
Chromate of potash

Bi-carbonateof potash cryst. (1 w

Tartrate of cobalt
Nitrate of potash .
Acetate of strontia
Arsenite of potash
Carbonate of copper .

Prototartrate of manganese
— iron .

Bi-phosphate of potash .
Chlorate of lime .

Arseniate of zinc . .

Molybdate of soda .

Tartrate of nickel .
Sulphate of cadmium
Lead ...

Ammonia-phosphate of soda
Saclactic acid ? . •

Chloride of barium
Phosphate of barytes
Citrate of potash « ,

ARCH,
I 93

S. 96

I

► 100

I

J

1

- 104

1824.]

Chlorate of soda .
Phosphate of bismuth
Chloride of bismuth
1 2 Water

Cryst. nitrate of lime (3 water)
Nitrate of strontia.

Table of Equivalent Numbers.

Bi-sulphate of potash
Protoxide of rhodium ?
Succinate of barytes
Acetate of barytes

Acetate of bismuth
■ of copper .

108

109

Silver . . .

Muriate of lime cryst. (5 water)
Arseniate of potash .

Tartrate of zinc .
Citrate of strontia
Sulphite of barytes .

Protoxide of lead . .

Chlorate of manganese .

Oxalate of barytes .

Tartrate of potash .

Phosphuret of lead .

Oxalate of bismuth .

Deutoxide of lead .

Crystallized carbonate of soda (7

water) . . .

13 Water.

Hydrated carbonate of ammonia
Sulphate of barytes
Nitrate of cadmium .

Chlorate of zinc . .

Oxide of silver . ,

Tartrate of strontia

Peroxide of lead .
Sulphate of bismuth
Sulphuret of lead .
Tungstic acid
Molybdate of potash
Binoxalate of potash
Benzoic acid
Perchloride of carbon
Rhodium ? . .

Crystallized sulphate of magnesia j
(7 water)

Chlorate of potash

Muriate of barytes (5 water)

Iodine ...

Jlydriodic acid . ,

Sulphuret of silver .

14 Water.

I- 110

112

114
115

116

117

118

119

( 120

123

124

125

126

Chromate of barytes .
Perchloride of tin .

Nitrate of barytes .

Arsenite of barytes
Phosphite of lead . . .

Nitrate of bismuth ■ .
Carbonate of lead
Borate of lead ? . .

Prototartrate of tin

Iodide of lithium . ' .
15 Water . .

Perchloride of copper .
Acetate of soda cryst. (6 water)
Citrate of barytes .
Sulphate of zinc cryst. ( water)
Perphosphate of copper .

Bi-sulphate of potash crystallized
(6 water) . .

Iodide of phosphorus

— — — - magnesium .

Sulphate of cobalt (crystallized
water) . . .

Citrate of bismuth .

Cryst. sulphate of iron (7 water)

Oxychlorate of potash
Chloride of lead . .

Phosphate of lead
Sulphate of nickel (crystallized 7

water) . . .

Arseniate of barytes
Carbonate of silver .

Borate of silver? . ,

Iodide of sulphur .
Arseniate of bismuth .

Starch? .

Ilydriodate of ammonia .

Sulphite of lead . .
Columbium ?

Peroxide of rhodium ? .

1 6 Water. . .

195

12S

130

132

134

135

136

13T

138
139

140

141
142

143

144

O?

196

Tartrate of barytes
Iodide of calcium
Chloride of silver .
Phosphate of silver
Tartrate of bismuth

Ben zo ate of lime .
Tungstate of lime
Oxalate of lead .

Iodide of sodium .
Cryst. nitrate of barytes (2
Sulphite of silver .
Iodide of cobalt .
Sulphate of lead .
Benzoate of soda .
Bichromate of potash
Columbic acid
Carbonate of soda (crys,

17 Water
Chlorate of barytes
Benzoate of cobalt
Iodide of nickel .
Oxalate of silver .
Benzoate of manganese
Sulphate of silver .
Benzoate of nickel
Borax (8 water) .

Iodide of zinc
Persulphate of copper (dry)
Chloriodic acid
Crystallized sulphate of

water) .
Succinate of lead .
Benzoate of zinc .
Acetate of lead .'

18 Water

Chromate of lead .
Iodic acid . .

Iodide of potassium

Nitrate of lead
Acetate of silver .
Tungstate of potash
Benzoate of potash

Iodide of antimony
Iodide of strontium

Chromate of silver
Citrate of lead ' ,

Table of Equivalent Numbers. [March,

19 Water . . .171

water)

water

soda (I0^>

}

145

146
147

148

149
150

151

J. 152

)

I 153

\

\ 154

)
156

157

158
159
160
161

162

164

165

166

}

168

169

170

Nitrate of silver .
Binarseniate of potash
Arsenite of silver •

Arseniate of lead .
Citrate of silver .
Tartrate of lead .
Binacetate of copper
Arseniate of silver
20 Water.

Iodide of cadmium

Bi-tartrate of potash

Iodate of ammonia

Malate of lead

Iodide of tin

Acetate of copper (crys. 6 water)

Tartrate of lithia and soda

Molybdate of lead

Tartrate of silver .

Pernitrate of copper (dry)

Chlorate of lead .

Protoxide of platinum ?

Acetate of lead (cryst. 3 water)
Iodide of copper .

Molybdate of silver
Bitartrate of potash (cryst.
Quadroxalate of potash
Iodate Of lime
Chlorate of silver .
Iodide of barium .

Iodide of bismuth
Iodate of soda

Tungstate of barytes
Benzoate of barytes
Benzoate of bismuth
Mercury .
Gold .

Binacetate of copper (cryst

Iodate of zinc
Protoxide of mercury

gold .

Potash.tartrate of ammonia

Subacejate of Mpper
Phosphuret of mercury
Iodate of pot ash .
Tartrate of sodfe and potash

water)

3 water)

172

174
176
179

180

181

182
183
184

185
188

189

190
191
192
193
194
195

197
198

200
207

> 208

210
212
213
214

1824.] Col. Beaufoy

Peroxide of mercury •

Protosulphuret of mercury

Prototartrate of iron and potash
Peroxide of gold ?
Iodide of lead

Benzoate of lead .
Bi-sulphuret of mercury

Iodide of silver

Protochloride of mercury
gold

Tungstate of silver
Benzoate of silver.

Iodate of baryta .
Iodate of bismuth.

Sulphuret of gold ?
Protosulphate of mercury

Crystallized persulphate of coppe
(10 water)

By-cyanuret of mercury
Persulphate of mercury

t Astronomical Observations.

| 216

}

218
224
229

232

235

236

238

243
245

248

250

252
256

Alum (dry)

Periodide of phosphorus

Protonitrate of mercury

Perchloride of mercury
Perphosphate of mercury .

Sub-binacetate of lead
Iodate of lead . .

Iodate of silver .

Bi-persulphate of mercury
Chloride of gold and sodium

Pemitrate of mercury .

Protiodide of mercury .
— — — — gold . .

Crystallized chloride of gold
sodium (8 water)

Subtriatacetate of lead
Periodide of mercury .
Alum (crystallized 25 water)

and

}

197

26-2

272

274
277
283

296

324
325

36S

386
459

487

Article VIII.

Astronomical Observations, 1824.
By Col. Beaufoy, FRS.

Bushei/ Heath, near Stanmore.

Latitude 51° 37' 44-3" North. Longitude West in time 1' 20-93".

Jan. 17. Emersion of Jupiter's second < 6 h 07' 47" Mean Time at Bushey.

satellite \ 6 09 08 Mean Time at Greenwich.

fin contact with the) ^ h j ./ *►« |
Jan. 26.* Jupiter's third satellite .{ planet's limb. .. J J-M.T.Bushey.

t Immersion 10 25 10 )

Jan. 29. Emersion of Jupiter's first ( 9 25 33 Mean Time at Bushey.

satellite \ 9 26 54 Mean Time at Greenwich.

Jan. 31. Emersion of Jupiter's second ( 1 1 21 S6 Mean Time at Bushey.

satellite ( ' • 22 57 Mean Time at Greenwich.

Feb. I. Jupiter's fourth Ylmmer. 7M8' 35" M.T.Bushey T- 49' 56" M.T.Gr.

satellite.... } Emer. 9 59 36 10 57

Feb. II. Immersion of 2 a Gemini by? 9 g , 47 . 6 siderial Tmie .

the moon )

Feb. 14. Emersion of Jupiter's first ( 7 43 56 Mean Time at Bushey.

satellite ( 7 45 17 Mean Time at Greenwich.

• According to the Nautical Ephemeris, the eclipse of this satellite took place at
13h 18' 35"; but the satellite immerged behind the planet, at 10 h 26' 31' Greenwich
time, making a difference of 2 h 52' 04".

198 Mr. Cumberland on [March,

Article IX.

On Animal Remains found in Caves. By G. Cumberland, Esq.

(To the Editor of the Annals of Philosophy.)

SIR, Bristol, Dec. 29, 1824.

When, in the Annals for February last, you did me the
favour to publish my remarks on the enigmatical cave at Picker-
ing, which has given rise to so many unsatisfactory conjectures,
I confess I was carried away with the then prevailing opinion,
that the remains of the animals found there had been localized to
the spot, and their assembling there for safety was in that case
not improbable at the rising of waters of the general flood. But
I have since felt, that the objection founded on climate is insur-
mountable, and that they could not have been dragged there by
the hyaenas is now, I believe, the most general belief; for not to
insist on what Dr. Knox asserted at the Wernerian Lectures,
reported in the Physical Journal, No. 16, viz. that the hyamas of
southern Africa are not in the habit of conveying their prey
away into dens, it seems impossible to reconcile to reason that
they should have found such various animals near together, as
the elephant, rhinoceros, ox, horse, hippopotamus, tiger, bear, and
wolf; or, if they had, that they should have been able to effect
such a labour, so much beyond their united strength, or to have
destroyed all the skulls by even their forcep jaws ; neither can
any one be made to believe, could all this be proved, that such
animals as these antediluvian hyaenas are described to be in point
of magnitude, would have left even the smallest remains of such
small bones as those belonging to the rat, mouse, raven, pigeon,
and lark. Ducks and partridges would have been but a mouth-
ful to them, and it is not very easy to imagine by what means
they could be able to catch them any more than rabbits and
hares.

Let us suppose the gnawed marks on the bones to be esta-
blished by comparison ; it proves nothing of their having been
gnawed where they were found ; and as to the polish acquired by
their feet and hair passing over them, that really must always
be considered as conjectural, and proves nothing as to locality.

Admit even that a considerable portion of original gelatinous
matter (as has been asserted) remained, it could only show that
the period since the destruction of these auimals had not been
very extended, not that they died there. Again, if no skull was
left entire, but only chips found, and solid parts of bones, or
angular fragments projecting through the stalagmite above, we
should be a little cautious in naming so many species, and varie-
ties of species, of small animals : — even Messrs. Cuvier and

1824.] Animal Remains found in Caves. 199

Clift might startle at this difficulty one would think. But as
this is a subject on which so few are competent to decide, and
so much has been advanced on the continent by supposed infal-
lible judges, that we must be silent on that head; only it does
seem strange, that if some are so evidently gnawed, more are
not so ; and I do not find one in that supposed state among the
immense mass that Mr. Cottle has collected from Oreston ; and
as some one must have been left if this was their den of slaugh-
ter, why have not their skulls been found — at any rate that of the
last survivor? Stress has been laid on these bones not having been
rolled, but I think that could not have been, or pebbles found
with them, in the places where they are found ; for if granite
rocks have been proved to have been removed by water hundreds
of miles, surely bones floating in masses might have been con-
ducted by currents from very distant parts from those where we
find them, and being lighter they would not have mixed with
gravel or beach stones at the retreat of the waters, but probably
washed up with mud, and entangled in each other, they fell into
these cavities on the retreat of the waters, or were carried in by
whirlpools, so as, after receiving many fractures, to be deposited
at length in a level bed such as they were discovered in, resting
on the original stalagmite, and when all was dry, receiving in the
course of ages an additional covering of a similar deposition.
This conjecture accounts also for their intermixture, as well as
fractured state ; for rolled bone, and wood, or ivory, are only
invariably found among ancient beaches of gravel such as now
lies below the land at Shorehampton, near Bristol, and which
has produced many specimens whenever the mine is opened to
gravel Lord de Clifford's park there, a deposit undoubtedly left
there on the borders of the Severn channel at the retreat of the
waters of the flood.

To come at the truth will be difficult, and therefore we are
obliged to Prof. Bnckland for the great pains he has taken in
bringing forward all that has hitherto been known On a subject
that seems so strongly to corroborate the Scripture history of the
Deluge ; but we must not in the history of natural events look
to any authority but that which is founded on circumstances
applicable to the event under discussion.

Yours, &c. G.Cumberland.

200 Mr. Giddt/' s Comparative Thermometrical Table. [March,

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« The above tables clearly show, that in severe winters the temperature
at Pisa (which is a place of great resort for invalids) and at Penzance
is as near as possible the same. The Thermometrical Register at Pisa
was kept at the Observatory, 6 miles E.S.E. from the city.

1824.] On the Volcanos at present in Activity. 201

Article XI.

An Account of the Volcanos at present in Activity.
By M. Arago.*

Some persons having appeared desirous of seeing in the
" Annuaire " an account of the volcanos now in activity, I
engaged to write it, but without having sufficiently reflected, as
I afterwards discovered, on the difficulty of this work. The
details with which most travellers have furnished us on these great
phenomena are incomplete, and extremely vague. In the esti-
mation of one, those parts of the earth from which a little smoke
arises, or upon which a few sparks are perceived, are volcanos ;
another gives this name only to mountains which incessantly
cast forth torrents of lava, burning matter, and ashes. The
first will insert in his catalogue the trifling flames of Pietra-Mala,
Barigazzo, Yelleia, of Persia, and Caramania ; the second
will place Santorini itself in the class of solfaterras. To this diffi-
culty must be added the still greater one of determining what
distance should separate two craters, that they may be considered
as two distinct volcanos. At TenerifFe the eruption of 1706
broke out at an opening two leagues distant from the Peak ;
that which destroyed Garachico burst out at an opposite side,
and at a point a league and a half distant from the Peak ; there
were then three leagues and a half between the two openings
without their being considered as belonging to two distinct vol-
canos. But, shall we consider the isle of Palma, where there
was an eruption of lava in 1699, as containing a volcano separate
from that of TenerifFe? Ought the destruction of a third of the
isle of Lancerote in 1730 to be considered as the effect of a
lateral eruption of the volcano of the Peak, or of a separate
volcano ? Analogous questions present themselves at every step,
and the means are wanting to answer them. I should, therefore,
have omitted printing this notice in the Annuaire, from which it
is desirable to exclude every thing that does not possess a cer-
tain degree of precision, if I had not had the advantage of con-
sulting the two persons to whom the physical history of the
globe is best known, MM. de Humboldt, and Leopold de Buch.

Volcanos of Europe and the adjacent Islands.

Vesuvius ; kingdom of Naples.

Etna; Sicily.

Stromboli ; Eolian islands.

Hecla; Iceland.

Krabla ; northern part of Iceland.

Katlagiaa-Jokul ; Iceland.

" From L'Annuair* pourl'an 1824.

202 M. Arago on the [March,

Eyafialla-Jokul ; Iceland, south-east of Hecla.

Eyrefa-Jokul ; ditto.

Skaptaa-Jokul ; ditto.

Skaptaa-Syssel ; ditto.

Wester-Jokul ; ditto.

Esk ; island of Jean Mayen.

Vesuvius, the only volcano now in activity upon the conti-
nent of Europe, has been repeatedly extinguished, and in com-
bustion. Before the reign of Titus, this mountain was much
visited, and is mentioned only on account of its extraordinary
fertility. Vitruvius and Diodorus Siculus, who lived in the time
of Augustus, do indeed state, upon historical authority, that
Vesuvius had formerly vomited fire like Etna ; but these state-
ments refer to remote and nearly forgotten periods.

It was on the 24 th of August in the 79th year of the Christian
era, that Vesuvius was rekindled. This eruption buried the
cities of Herculaneum, Pompeii, and Stabiaea ; and it will be
recollected that Pliny, the naturalist, perished, as the victim of
the ardent curiosity with which he was inspired by this interest-
ing phsenomenon.

After the eruption of the year 79, the volcano remained in
combustion for 1000 years ; still later it appeared to be totally
extinct; so that in 1611, the mountain was inhabited almost to
the summit, and there were a copse and small lakes in the inte-
rior of the crater.

Etna. — Pindar, who lived in the year 449 before the Christian
era, mentions Etna as being in a state of combustion. Thucy-
dides has preserved some details of the eruption which occurred
476 years before Christ. As to Homer, he does not even men-
tion the mountain, although in the Odvssey he disembarks
Ulysses in Sicily. The silence of a poet who has always been
admired for the extent and universality of his knowledge, has led
to the probable supposition, that long before the time of Homer
the volcano was extinct. The Roman historians, both of the
middle ages and of modern times, have described so great a
number of eruptions of Etna, that it probably would not be diffi-
cult to prove that during a period of 2000 years it was never
extinct for a whole century.

Seneca has observed that volcanic mountains do not supply
the combustible matter of the fire, but that they merely give it
vent. Father Kircher seems to have commented on these words
of the Roman philosopher, when in the fourth book of his Sub-
terranean World, he has advanced the opinion that the matter
ejected from Etna, would, if formed into one mass, form a moun-
tain 20 times larger than Etna itself. The work of Father
Kircher appeared in 1660. Nine years afterwards a single
eruption of the volcano, covered with lava a space of six leagues
long, two and a half in width, and of a mean depth of at least

1824.] Vokanos at present in Activity. 203

100 feet. According to Doloinieu the eruption of 1755 produced
a current of lava four leagues in length, half a league wide, and of
at least 200 feet mean depth. In reflecting on the immense void,
that eruptions so considerable must have produced in the moun-
tain and at its base, is there not yet cause for wonder that erup-
tions, like that of 1787 for instance, should still occur at the
summit, the height of which is 10,600 feet above the level of
the sea.

Stromholi. — M. de Humboldt has remarked that the activity
of volcanos appears to be in the inverse ratio of their mag-
nitude. Stromboli is a striking confirmation of this principle ;
it is perpetually sending forth flames ; but with this peculiarity,
that for 2000 years it has not, strictly speaking, made any erup-
tions, although the nature of the surrounding country shows, that
it was formerly subject to them. Mount Epomea, in the island
of Ischia, ought not to be considered as a volcano, but it would
probably become one if Stromboli were extinct.

Santorini was the site of a great eruption in 1707. As this
phsenomenon has not been repeated, and as the island exhibits
no crater, of the true chimney of a volcano, 1 have not inserted
it in the catalogue.

Volcanos in Iceland. — The last eruption of Hecla occurred in
1766. The eruptions of this volcano, according to Sir George
Mackenzie, are not in general so extensive as they have been
represented. The most recent eruption of Krabla occurred in
1724. In 1750, between January and September, there were
five eruptions of Kattlagiaa ; since which period this volcano
remained perfectly tranquil, until the 26th of July, 1823, when
strong eruptions occurred accompanied with earthquakes.

Eyajialta-Jokid, which appeared to be extinct for more than
a century, emitted torrents of flames from its summit on the 20th
of Dec. 1821. Eye-witnesses report, that the column of fire was
still visible on the 1st of Feb. 1822, and that it projected stones
weighing from 50 to 80 pounds, with so much force as to cause
them to fall at a distance of two leagues from the mountain. The
mountain burst at its base on the 26th June, 1822, and a great
quantity of lava issued from it.

Eyrefa-Jokul. — The last eruption occurred in 1720

Skaptua-J oknl and Skaptaa-Syssel. — The eruptions of these
two volcanos, which occurred in 178 , occupy the first rank in
phenomena of this nature ; they ravaged an immense extent of
country. During a whole year after the eruptions, the atmo-
sphere of Iceland was mixed with clouds of dust, which the sun's
rays scarcely penetrated.

Wester-Jokul. — An eruption of ashes and stones happened in
January, 1823.

Esk. — This volcano was discovered and visited in 1817 by
Mr. Scoresby. It made an eruption at the end of April, 1818 ;

204 M. Arago on the [March,

columns of smoke arose every three or four minutes to the height
of 4 or 5,000 feet.

Islands near the Continent of Africa.

No volcano, strictly so called, is with certainty known to exist
in Africa ; but the islands which geographers consider as the
dependancies of that continent, contain several volcanos.

El Pico. — Island of El Pico, Azores.

Peak of Teneriffe. — Island of Teneriffe.

Fuego. — Island of Fuego, Archipelago of Cape Verd.

Les Trois Salasses. — Isle of Bourbon.

Zibbel-Teir. — Island of this name, Red Sea.

Ascension Island.

El Pico. — This mountain is the only one of the Azores which
rises in the form of a cone ; the only one entirely composed of
trachyte, and the only one in which there is a vent always open.
Geologists are agreed in the opinion, that the great currents of lava
which flowed in 1812 in the Isle of St. George were the results
of a lateral eruption of the volcano of El Pico. They explain in
the same way the sudden formation of an isle in the neighbour-
hood of St. Michael in 1811. This isle was taken possession of
in the name ef the King of England, by the Captain of the
Sabrina, who witnessed the event ; it has since totally disap-
peared. The part of the sea in which this isle arose is not less
than 80 fathoms deep.

Peak of Teneriffe. — This volcano appears to be much more
agitated on its sides than at its summit. Neither flames
nor lava have issued from it from time immemorial, nor any
smoke which could be seen at a distance. The last erup-
tion, that of 1798, took place laterally in the mountain of Cha-
horra. It continued for more than three months. Various
fragments of rocks, of very considerable size, which the volcano
projected from time to time into the air, occupied, according to
the observations of M. Cologuan, from 12 to 15 seconds in fall-
ing. Teneriffe had suffered no eruption for 92 years, until that
of 1798, which began suddenly on the 9th of June.

Immense torrents of lava flowed upon the island of Palma,
25 leagues distant from the Peak, through new volcanic open-
ings which were formed in 1558, 1646, and 1677. The isle of
Lancerote was also destroyed by an eruption in 1 730.

Fuego. — Scarcely any details are known respecting the isle of
Fuego. It would appear, in opposition to an opinion formerly
adopted, that no other active volcanos exist in all the Archipe-
lago of Cape Verd.

Volcano of Bourbon. — There are few volcanos which are in a
state of greater activity than that of Bourbon. Its last eruption
occurred on the 27th of Feb. 1821. It formed three currents of
lava, which opened a passage in the summit of the mountain, a

1824.] Volcanos at present in Activity. 205

little below the true crater. One of these currents did not
reach the sea till the 9th of March. Some time after the
explosion, there fell in many parts of the island, a shower
composed of black ashes, and long flexible threads of glass,
resembling golden-coloured hair. This phenomenon, which was
chiefly noticed in 1766, has been considered as peculiar to the
volcano of Bourbon ; but Hamilton states, that he found similar
glassy filaments mixed with the ashes by which the atmosphere
of Naples was obscured during the eruption of Vesuvius in
1779.

Those persons who have not particularly studied volcanic
phenomena will probably be surprised to learn, that in 1821 the
ignited lava of the volcano of Bourbon should be six whole days
in traversing, upon inclined ground, the short distance from the
crater to the sea. But it ought to be observed that lavas are not
perfect fluids, and that in proportion as they cool, their progress
must slacken. In 1805, M. de Buch observed a torrent of lava
issue from the summit of Vesuvius, and reach the sea shore in
three hours ; but the history of volcanos offers few instances of
similar rapidity.

In general the motion of lavas is slow ; those of Etna are
whole days in flowing a few feet in the flat lands of Sicily. The
external part is sometimes fixed and stationary ; while the cen-
tral mass, still fluid and incandescent, continues to flow. The
great viscidity of the lavas, when slightly cooled, occasions them
to be extremely thick on the edges even when they flow in a
level country.

Zibbel-Tier, accordingto Bruce, is in 15 T V degrees north latitude.
The summit of the mountain has four openings, through which
there issue thick columns of smoke.

Few details are known respecting the volcano of Ascension
Island. As to that of Madagascar, which is stated to project
immense columns of aqueous vapour visible at a distance of 10
leagues, its existence has not appeared to me sufficiently proved
to induce me to insert it in the catalogue.

Volcanos of America.

NortJi-west Coast.

Mount Saint-Elia.
Mount del Buen Tiempo.
Volcan de las Virgenes ?

Mexico.

Orizaba or Citlaltepetl.

Popocatepetl or volcan de la Puebla.

Tuxtla.

Xorullo.

Colima.

206 M. Arago on the [March,

Guatimala and Nicaragua.

Volcano of Soconusco.
Sacatepeque.
Hauiilpas.
Atitlan.

Fuegos de Guatimala.
Acatinango.
Sunil.
Toliman.
Isalco.

Sacatecoluca, near the Rio del Empa.
San- Vicente
Traapa.
Besotlen.

Cocivina, near the gulf of Conchagua.
Viego, near the port of Rialexo.
Momotombo.

Talica, near San-Leon de "Nicaragua.
Granada.
Bombacho.
Papagallo.
Barua, south of the gulf of Nicoya.

Volcano of Sotara.' 1 ^ c n

Purace./ Grou P° fP( W an -

Pasto.

Rio Fragua.

Volcano of Cumbal.*\ _ c ., . , ,

Chiles C Gr ° u P of tne P rovmce de los
Azufral.

ral. J

Group of Quito.
Volcano of Antisana.

Rucupichincha.
Cotopaxi.
Tunguragua.
Sangay.

Volcano of Arequipa (Peru).

Group of Chi/i.

Volcano of Copiapo.

Coquimbo.
Choapa or Lisnari.
Aconcagua.
Santiago.
Petoroa.

1824.] Volcano* at present in Activity. 207

Chilian.

Tucapel.

Callaqui.

Chinal.

Villa-Rica.

Votuco.

Huaunauca.

Huaiteca.

San-Clemente.

Antilles.

Volcano of Saint- Vincent.
Saint-Lucia.
Guadaloupe.

It is unknown whether the volcanos of the north-west coast
have recently made any eruption.

Orizaba is 17,300 feet high ; the streams of lava observed on
the sides of the mountain remove every doubt as to its volcanic
nature ; but no recent eruptions are known of.

Popocatepetl has smoked ever since the conquest of Mexico.
Cortes relates indeed, that he ordered ten of his most courageous
companions to reach the summit, and to discover the secret of its
smoking, which he wished to communicate to Charles V. This
volcano is always burning, but it has projected lava from time
immemorial. Its height measured by M. de Humboldt is 17,600
feet.

The volcano of Tuxtht is situate to the south-west of Veracruze.
Its last very considerable eruption occurred in 1793. The
ejected ashes were then carried as far as Perote, a distance, in a
straight line, of 57 leagues.

Xorul/o. — M. de Humboldt remarks, that the catastrophe
which gave rise to the volcano of Xorullo, is, perhaps, one of the
most extraordinary physical revolutions which the annals of
our planet contain. In the middle of a continent, at 36 leagues
distance from any active volcano, the earth rose to the extent of
three or four square miles in the form of a bladder, on the night
of the 28th and on the 29th of September, 1759. In the centre
of a thousand inflamed cones, six mountains from 1,300 to 1,700
feet high above the original level of the surrounding country, sud-
denly arose. The principal of them is Xorullo, the height of
which is 1 ,700 feet. Its eruptions continued without cessation
until the month of February, 1 760. The subterranean fire is now
very active.

The volcano of Colima, the most western of those in New
Spain, ejects now hardly any thing but ashes and smoke. Its
height is about 1,000 feet.

M. de Humboldt has made the important observation, that the
Peak of Orizaba, Popocatepetl, Colima, and other extinct vol-

208 M. Arago on the [March,

canos, are in a line, as if they proceeded from one fissure or vein,
in a direction perpendicular to that of the great chain of moun-
tains which traverses Mexico from the north-west to the south-
east.

The volcano of Xorullo just mentioned interposed itself in
1759 in the line of the ancient volcanos. This curious arrange-
ment, which we shall observe in other places, exists also, accord-
ing to M. Daubuisson, in the extinct volcanos of Puy-de-D6me.

The volcanos of Gnatimala which have most lately erupted,
are Los Fuegos of Guatimala, Isalco, Momotombo, Talica, and
Bombacho. These active volcanos, and the sixteen others
whose names have been mentioned, are contained between the
10° and 15° of north latitude, and in a line corresponding with
the general direction of the Cordilleras.

The connexion of the volcano of Pasto with those of the pro-
vince of Quito was shown in a striking manner in 1796. A thick
column of smoke had existed from the month of November,
1796, from the volcano of Pasto ; but to the great surprise of all
the inhabitants of the city of that name, the smoke suddenly dis-
appeared on the 4th of February, 1797. This was precisely the
moment at which, at 65 leagues further south, the city of Rio-
bamba, near Tunguragua, was destroyed by a tremendous earth-
quake.

Antisana is 20,000 feet high. No eruption of this volcano is
known to have happened since the year 1590.

The last eruption of Rucupichincha occurred in the year 1660.

Cotopaxi made an eruption in 1742, while the French acade-
micians were measuring a degree of the meridian in its neigh-
bourhood. The column of flames and of burning substances
rose 500 toises above the mountain. The snows which had been
heaped up during two centuries, from the summit of the mountain
to 500 toises below it, were melted en masse ; the torrent which
it occasioned rushed into the plain with impetuosity, forming
waves from 60 to 100 feet in height. At a distance of three or
four leagues from the mountain, the rapidity of the water, in the
opinion of Bouguer, was from 40 to 50 feet in a second. Six
hundred houses were destroyed, and 700 or 800 persons were
drowned in the torrent. The eruptions of 1743 and 1744 were
still more disastrous.

Bouguer and La Condamine, having examined the remaining
traces of the great eruption of 1533, the memory of which is
preserved from generation to generation among the inhabitants,
they found that the volcano had ejected to a distance of more
than three leagues, stones containing from 70 to nearly 100
cubic feet, or to use the expression of La Condamine, larger than
the cabin of an Indian. The origin of these stones was unques-
tionable ; they formed lines in every direction towards the
volcano. It does not appear that Vesuvius has ever ejected
stones to more than 4,000 feet high.

1824.] Volcanos at present in Activity. 209

Twtguragua made an explosion in 1641.

Sangay has remained constantly burning ever since the year
1728.

Chimborazo does not appear in the list; for although no one
disputes its volcanic nature, no account of its eruption has been
preserved. The case is the same with Carguairazo. The inun-
dation of mud which in 1698 covered 18 square leagues of land
was not the effect of an eruption, properly so called. When
Carguairazo fell, the waters which it concealed in its bosom were
precipitated impetuously into the plain, and occasioned the dis-
asters mentioned by the historians of America.

There are in some maps of Chili more volcanos marked than I
have placed in the catalogue; but I felt it proper to confine
myself to what appeared to me to be most certain ; and I ought
further to add, that of the sixteen volcanos of this country whose
names have been given, several are now probably extinct.
Peteroa made an eruption in 1762 ; Villa-Rica in 1640, &c.

In looking at the coast of America, it will undoubtedly have
occasioned surprise to find no volcano, either between the 2d
and 16th degree of south latitude, or between the 17th and 27th
degree. If the volcano of Arequipa did not exist, the range of
Guatimala and Nicaragua, the groups of Popayan and los Pastos
would be separated from the long track of Chili, by a space of
25° of latitude, totally without volcanos. Although Peru con-
tains only one volcano, there are i'ew countries in the world
where earthquakes are more severely felt, and where they make
greater devastation. They frequently occasion the formation of
immense fissures, over which bridges are built to preserve com-
munication between different provinces. One of these fissures,
after the earthquake of 1 746, was a league in length, and nearly
seven feet wide.

The volcano of the island of St. Vincent ejected lavas in 1718
and 1812. The ashes of the latter eruption were carried by the
upper counter current of the trade winds, to the island of Barba-
does, 30 leagues to the west.

At St. Lucia, there is a continual formation of sulphur, occa-
sioned by the condensation of the vapouis, which rise from the
crater called Oua/ibou, at a height of 1200 to 1800 feet. Jets of
hot water are also observed there.

The volcano of Guadaloupe, at a height of about 4,800 feet,
made its last eruption in 1797. It then ejected pumice, ashes,
and clouds of sulphureous vapours.

I shall conclude these notices relative to the volcanos of
America, by remarking, that no active volcanos occur either at
Buenos Ayres, at Brazil, Guyana, or on the coast of Venezuela,
or in the United States ; that is to say, at any point of the coast
to the east of this great continent. '1 here exist to the east of the
Andes only three small volcanos situate near the sources of the

\ew Series, vol. vn. p

210 M. Arago on the [March,

Caqueta, the Napo, and the Morona, and which, according to
M. Humboldt, probably result from the lateral action of the vol-
canos of Popayan and Pasto.

Volcanos of Asia.

Elburs, in Persia.

Tour fan, central region of Asia ; latitude 43° 30' ; longitude
87° IT.

Bisch-Balikh.— Ibid. Latitude 46° 0' ; longitude 76° 11'.

Avatscha. — Kamtschatka.

Tolbatchick. — Ibid. ; and three other volcanos more consider-
able than the two last.

Kourile Islands.
Nine active volcanos, according to Kracheninnikou.

Aleutian Islands.

Four volcanos atOuminga, Ounalaska, Omnak, andOurimack.
The last made a great eruption in 1820.

Islands of Japan.

Ten volcanos. The island of Niphon, which is the most
extensive, contains three. According to the evidence of
Kcempfer, several of the volcanos of Japan are subject to very
violent eruptions.

Islands of Lieou-Kievu.

The Sulphur Island emitted a thick sulphureous smoke, when
the Lvra, commanded by Capt. Basil Hall, passed near it on the
13th of Sept. 1816.

Elburs has been mentioned by several travellers as a volcano
in activity ; but the fact is doubtful, and at any rate there is no
evidence to prove that it has recently made any eruption.

The mountains of Tout fan and Bisch-Balikh are represented
as continually emitting flames and smoke. It is stated that the
Kalmucks collect sal ammoniac there, which they export to
the different countries of Asia.

Avatscha made an eruption in 1779, while Capt. Clerke was
iu the harbour of St. Peter and St. Paul. In 1787 La Peyrouse
aud his companions saw flames and smoke continually at the
summit of the same mountain.

An eruption of Tolbatchink occurred in 1739. A third volcano,
and more considerable than the two others, but of which Capt.
Clerke does not give the name, ejected a permanent column of
smoke from its summit. Since this, two new volcanos have
made eruptions at Kamtschatka.

1624.] Volcano* at present in Activity. 211

Oceania.

Philippine Islands.

Five active volcanos. Travellers have hitherto given only
vague accounts of the volcanos of the Philippines. Albay is the
name of that in the island of Luconia ; Taal is situate to the
south of Manilla ; Fuego to the south of Luconia ; Mindanao
also contains a volcano.

Borneo.

Geographers agree in assigning volcanos to Borneo, but with-
out stating either their number or situation with precision.

Barren Island.

Barren Island contains a very active volcano of nearly 4000
feet high, which frequently ejects immense columns of smoke,
and red-hot stones, of the weight of three or four tons. Its lati-
tude is 12° 15'. Its distance from the most eastern of the
Andaman Islands is 15 leagues ; the island is not more than six
leagues in circumference.

Sumatra.

Four volcanos are marked by Marsden in his map of Sumatra ;
but as the interior of the island is very little known, there proba-
bly exist a greater number.

Java.

The island of Java contains a great number of volcanos
arranged in right lines ; their names and the dates of their erup-
tion are the following :

Salak, 1761 ; eruption.

Tankuban, 1804 ; sulphureous vapours.

Guntur, 1807 ; eruption.

Gagak, ; partial combustion.

Chermai, 1805; eruption.

Lawn, 1806 ; sulphureous vapours.

Arjuna, ; permanent column of smoke,

Dasar, 1804 ; eruption.
Lamongan, 1806 ; eruption.
Tasher, 1706 ; eruption.
Klut, 1785 ; eruption.

Arjuna is 10,614 feet high; this mountain is not, however,
the most lofty in the island.

Mount Papandayang was one of the principal volcanos of
the island; but it is no longer in existence. Between the 11th
and 12th of August, 1772, after the formation of a great lumi*
nous cloud, the mountain totally disappeared in the bowels of
the earth. It has been estimated that the land thus ingulphed
was 14 miles long and 6 miles broad.

p2

212 M.Aragoonthe [March,

Sumbawa.

Tomboro, in Sumbawa, made a violent eruption in 1815. The
detonations were heard in Sumatra at places 300 leagues distant
from the volcano in a right line.

F/ores.
The volcano of this island was seen by Bligh.

Daumer.
Daumer contains a volcano.

Dampier, in 1699, saw a volcano constantly in combustion
on a small island between Timor and Ceram.

Island of Banda.

Goouour/g-Api, in Banda, made a violent eruption on the 11th
of June, 1820, during which it ejected red-hot stones as large as
the habitations of the natives. Several of these stones rose to a
height double that of the mountain.

Moluccas.

In the island of Ternate, there is a burning volcano. Tidore
is the name of one of these islands, and of an active volcano
which it contains.

According to geographers, Celebes contains several active
volcanos ; they do not mention their situations.

Sanguir. — Between Mindanao and Celebes, is one of the
greatest volcanos of the globe.

New Gttinea.

Two volcanos were burning, in 1700, in the island of New
Guinea, when Dampier explored the coast of it.

New Britain.

There are three volcanos in the Archipelago of New Britain.
D'Entrecasteaux saw an eruption of that which is situated in
latitude 5° 32', and 145° 44' of east longitude, the 29th of June,
1793. A torrent of lava Mowed into the sea, and formed differ-
ent cascades. Lemaire and Schouten formerly saw an eruption
of the same volcano.

The Archipelago of FEs-piritu Santo. — The island of Amhrym,
in this Archipelago, which Bougainville called the Great Cyclades,
and Cook the New Hebrides, contains an active volcano. That
of Tanna is also volcanic. ]n Aug. 1774, Cook witnessed one
of its eruptions. The volcano cast forth flames, ashes, and
stones of a size at least equal to that of the great boat
belonging to his ship. In April, 1793, d'Entrecasteaux and his
companions saw a thick column of smoke on the top of the
mountain.

1824.] Volcanos at present in Activity. 213

Archipelago of the Ladrones.
There are nine volcanos in this Archipelago ; but I do not
know if they are all to be placed in the class of those which are

still burning.

Sandwich Islands.

The Mouna-Roa, in Owhyhee, appears to be, or at least to
have been a volcano ; but is it the same as the mountain of
Mowee, which Vancouver has called the Volcanic Mountain.

The Island of Amsterdam.
The island of Amsterdam was burning when D'Entrecasteaux
saw it in the month of March, 1792. Some attribute this phe-
nomenon to the effect simply of a great fire ; others have con-
cluded that the island contains a volcano.

The Islands of the Marquis de Traverse.
The islands lately discovered by the Russian navigators,
between New t Georgia and Sandwich Land, contain an active
volcano. There exists one equally so in Sandwich Land.

General Summary.
Number of active volcanos.
On the Continent. In the Isles. Total.

Europe 1 11 12

Africa 6 6

America ... 58 3 61

Asia. 8 24 32

Oceania .... 52 £>2

"67 ~96 163

Before I finish this account, I shall remark, that if the two
volcanos in the central part of Asia are excepted, the existence
of which may appear doubtful, not one will be found in the pre-
ceding list which is more than 50 leagues from the sea. It
seeimTdifficult not to draw the conclusion from this curious fact,
that water acts an important part in volcanic eruptions.

A phenomenon equally worthy the attention of observers, is
the propagation of sound which precedes or accompanies erup-
tions. It has been previously shown, that in 1815 the explosions
at Tomboro, in Sombrero, were heard at Sumatra, distant in a
right line 300 leagues from the mountain. M. de Humboldt
states in his excellent work a circumstance nearly as surprising.
The explosions which announced the first eruption of ashes from
St. Vincent, did not appear louder to the inhabitants of the
island than the report of a large cannon. These explosions not-
withstanding were heard perfectly upon the Rio-Apure, at the
confluence of Rio Nula, 200 leagues from the volcano, which is

214 On certain Instruments formerly used for [March,

equal to the distance of Vesuvius from Paris. The report seemed
so well transmitted by the air, that it was mistaken for the dis-
charge of artillery, and was the cause of several military move-
ments in various parts of the American continent.

Article XII.

An Account of certain Instruments formerly used for the Purpose
of Blasting in the Lead Mines of Colonel and Mrs. Beaumont,
at Allenheads. Communicated by Mr. Thomas Crawhall, gf
Newcastle-upon-Tyne .*

These sketches represent an iron instrument found in Allen-
heads lead mines, supposed to have been formerly used in blast-
ino-, the length of which was 2| or 3 feet ; the upper part having
since been cut off, there only now remain 6 inches above the
bended part, which is 1^ inch square to the elbow, forming an
angle of about 10°; is of a cylindrical shape, slightly tapering
to the other end, which is one inch in diameter. On the out-
ward side of the angle, along the circular part, is a groove six
inches in length, of one-quarter inch broad, and of similar depth,
projected (it is supposed) to receive the train of gunpowder, per-

• From the Archseologia iEliana, vol. i.

1824.] the Purpose of Blasting in Lead Mines. 215

taining to the charge : the application of which has been to
drive it tightly into the hole bored in the rock above the powder,
and the upper part fixed by strong timbers placed across the
top for the purpose of preventing it being thrown out, without
the desired effect.

Another instrument of iron, found in the same
lead mines, differs from the above, in wanting the
square bar at top, and in place of the hollow on one
side, is cylindrical, and has a tube, one inch diameter,
to nearly the upper end, where it is flattened, and
has a shoulder projecting half an inch on each side,
resembling the head of a spear, and apparently
intended for fixing across it bars of iron or timbers,
to oppose the violence of the ignited gunpowder.

At the round end of the cylinder is a perforation
a, communicating through the hollow tube, with
another at b, placed for a touch hole on one side, l-£-
inch below the shoulder, and 8 inches distant
from the other end.

A tradition exists among the miners, that formerly
strong timbers and wedges were used for fixing down
the charges in blasting, to hinder explosion without
effect ; but no further explanation, as to the mode
in which this was achieved, is to be obtained, neither
in regard to the process of charging, nor of the tools
used. It is highly probable, however, that such
application might have been, and was adopted, for securing the
two instruments above described.

A series of five more of these instruments have been found in
the same mine, of the respective lengths of 84, 10, 10^-, and 12
inches.

There was also discovered, in opening some old workings at
the west end of Allenheads lead mines, about a month since
(Jan. 1820), a tool, formerly used, it is conjectured, for the pur-
pose of blasting with gunpowder, or rather, in forming a commu-
nication with it in the rock to be exploded. The spot where it
was found is in the Great Limestone there, about 40 feet from
the surface. The latest record of this place having been wrought,
was in the year 1716, since which period this part of it has been
entirely rilled up with rubbish and fallings in of the vein, and
only recently re-opened ; when the following (see next page),
with some other instruments, were discovered in one of the flatts
in the limestone. The oldest workmen of the present day do
not recollect their use, nor did they ever hear of such tools
employed for the purpose ; they seem, however, to have been
meant for it, and their application as follows: — After having
drilled a hole in the rock to be blasted, with a chisel or jumper
sufficiently deep, the gunpowder is put into the bottom of it, say
to the depth of three or four inches ; next the tool sketched

a'

216

On certain Instruments formerly used for [March,

llu -

3

5*

OS

\a

which is round at one end, one inch in diameter, with a hole in
the centre about one-eighth of an inch, which communicates
with another of the same dimensions, about one and one-fourth
inches from the other end on the cylindrical side, the opposite
being flattened from within one inch of the bottom, or circular
end, to one-third of an inch thick at the other extremity ; this
hollow cavity appears to have been filled with powder, which,
when the instrument was placed in the hole, would immediately
communicate with the charge. In this situation, it is presumed,
wedges (of wood) were driven against the flat side of the iron
tube, to resist the force of the gunpowder,
when fired through the touch-hole marked a,
by a train or match laid for that purpose. How
long this has been in disuse is altogether uncer-
tain, even the name is forgotten : it Is probable
a century might since have passed away.

Nearly in the same spot with the above, to
which I annex a sketch, a tool of more recent use
was found, called by the miners the stock and
feathers ; and remembered by some to have
been occasionally used about fifty years ago, par-
ticularly in wet situations, where gunpowder
could not, without great difficulty, be applied.
A perforation was made in the stratum, say four
to six inches deep ; placing two thin pieces of
iron, called the feathers, which are rounded on

1824.] the Purpose of Blasting in Lead Mines. 2Y1

one side and flat on the other, in this hole, the former being
next to the rock, the wedge or stake was driven between until a
portion of it split asunder.

This wedge also was found near the same place
with the preceding, of six inches in length, and one
and one-fourth inches square, tapering to a point,
having a hole one-fourth inch square, through it, at
one and a half inches from the top ; this, according to
the reports of very old miners, was intended to receive
a small rod of iron, by which, one man held, whilst
another drove the wedge ; but not used during the
life of any present workman.

At what period the present method of blasting was
introduced into these mines cannot be ascertained. A person
now residing there, recollects to have heard his father (who died
thirty-nine years ago at the age of sixty-seven) say, although it
took place before his time, that prior to the pricker and drive-all
being used, it was so hazardous an experiment, that two men
were specially appointed, whose province it was to visit the dif-
ferent workings, for the express purpose of charging and blast-
ing, after the holes had been prepared. Another, who, as well
as his father and grandfather before him, has been a pickman
for sixty years past, has a faint remembrance of hearing very old
men say, that formerly stemples were employed, but has no
knowledge as to the process, nor ever saw any other mode prac-
tised than the present ; but that the stock and feathers had been
in use during both the lifetimes of his father and grandfather.

Article XIII.

Inquiry how far the Opinions generally entertained of the Inuti-
lity of Observations of the Eclipses of Jupiter's Third and
Fourth Satellites, are well or ill founded. By J. South, FRS.

(To the Editor of the Annals of Philosophy.)

DEAR SIR, niackman-ntreet, Feb. 23, 1824.

To the advancement of natural knowledge there is probably
no one thing so inimical as prejudice, and perhaps there is no
science, which has suffered so much from this common enemy to
all, as has astronomy. To enumerate the various mischiefs
which this busy fiend has inflicted upon this peculiar science
would be foreign to the present purpose. Suffice it to say, its
baneful effects have been not only felt by physical, but also by
practical astronomy.

After the discovery of telescopes (as might be expected), we find
them employed upon Jupiter and his satellites, more than wpon any

218 Mr. South on the Eclipses of [March,

other object. The phenomena offour moons were naturally interest-
ing, nor was the inquiry unattended with important consequences.
The velocity of light repaid the labours of Roemer, and the eclipses
of the satellites opened a new, easy, and at that time a compa-
rative accurate mode of determining the differences of longitude
of distant stations. Hence astronomers were taught to look out
for these phenomena, and their observations became recorded :
in proportion, therefore, as the opportunities of observing these
eclipses were more or less frequent, were they supplied with
means of improving their tables ; ,till at length something like
accuracy was arrived at, as far as relates to those of the first and
second satellites ; to this also we must add another cause which
will be found in the nature of the instruments at this time em-
ployed ; for the rapid motion of these two satellites is such, that
the intervening period between their first entrance into the
shadow, and their complete obscuration by it, is short; hence
telescopes were able to give something like uniformity to the
observations of various observers — in short, theory and practice
assisted each other.

But not so with the outer satellites ; eclipses of them were
comparatively of very rare occurrence, and the time of their
entering the shadow till their complete obscuration being many
times greater than in the case of the two first satellites, the
observations became more difficult ; and the instruments were
inadequate to the purposes for which they were now wanted:
observations, therefore, of different observers differed considera-
bly with each other, and theory and practice were everlastingly
at variance. Hence observations of these satellites came into
disrepute, and almost into disuse.

At length, however, in the preface to a work entitled " Tables
Ecliptiques des Satellites de Jupiter," the monstrous discordan-
cies between the existing observations of the eclipses of the
third and fourth satellites were dwelt upon, with considerable
energy, by the celebrated Delambre ; and, perhaps, to the senti-
ments expressed by this great man, may we trace the principal
cause why at the present moment, observations of the eclipses
of these two satellites are almost generally neglected. When,
however, prejudice seems distributed by one whose name, like
that of Delambre, is never mentioned but with respect, does it
become dangerous; and more and more imperative is it, upon the
humblest labourer in science, to point out the errors which it
leads to — this must plead my excuse for the present communi-
cation.

As the work to which I allude, may not be in the library of
every practical astronomer, I shall quote from it some of the
passages calculated in my mind to prejudice observers.

Page 51. — Having alluded to some trifling equation which
might be applied as a correction to his tables of the third satel-
lite. He says, " Je n'ai pousse l'examen plus loin ; mais il
parait en resulter que cette equation ne s'accorde pas plus avec

1824.] Jupiter's Third and Fourth Satellites. 219

l'observation qu'avec la theorie ; et si la theorie est imparfaite,
s'il reste a decouvrir quelqu' inegalite sensible, elle depend du-
moins d'un argument tout-ti-fait different. Ce n'est pas d'ail-
leurs sur quelques observations isolees qu'il faut cbercher a recti-
fier des tables fondees sur 140 ans d'observations. A la veritc-j
toutes ces observations sont incertaines ; mais celles qu'on leur
opposerait ne sauraient etre beaucoup plus sures ; etl'on encon-
viendra sans doute, quand on verra Messier et Mechain, dans la
raeme ville et presque dans le meme quartier, tous deux munis
d'excellens instrumens et d'une vue excellente, ne s'accorder
cependant qu'a. quelques minutes pres sur la meme eclipse. II
est evident, de meme, que pour les differences des meridiens, on
ne peut se fier qu'au premier satellite ; les autres ne sont guere
bons qu'a eclaircir quelque point de physique celeste ; le pre-
mier satellite est le seul qui puisse etre vraiment utile aux astro-
nomes et aux geographes. Mais ce satellite lui-meme peut-il
s'observer avec une precision bien parfaite ? Quel astronome
osera repondre de 10'' sur l'observation qui lui paraitra faite dans
les circonstances les plus favorables ? En rassemblant les obser-
vations faites pendant cent ans a Paris et a Greenwich, on n'a
pu trouver qu'a 10"pres la difference entre les deux meridiens."

Page 55. — He says, " D'apres ces remarques, le calculateur
ajoutera s'il juge a. propos, 18 a 19" a toutes nos epoques du
troisieme satellite ; mais nous sommes loin de lui garantir l'ex-
actitude de cette correction ; et que font en eftet 18" pour des
observations qui ne sont presque jamais sures a 2 ou 3 minutes?"

Page 49. — We have observations of immersion and emersion
of the fourth satellite recorded,* and thus spoken of : "Pour
cette derniere eclipse, les astronomes de Paris different entre
eux de 3^ sur chaque phase." .

Page 55.— Speaking of eclipses of the fourth satellite, he
says, " Je trouve entre les observations d'une meme eclipse des
differences qui vont a 7, 8, 10, 12, et 14'; et ce qu'il y a d'eton-
nant, c'est que ces discordances enormes ne sont pas toutes vers
les limites. J'en trouve une qui est de 29' 15", mais la demi-
duree calculee n'etaitque de 16"."

1 . We are not told what instruments Messier and Mechain
employed, whether immersions or emersions were observed ; nor
do we know any more, than that their observations on the same
eclipse differed some minutes ; hence therefore the statement
only proves, that differences of longitude could not be gotten by
reference to the computed tables.

The assertions that differences of meridians can only be pro-
cured by the first satellite ; that it alone can be truly useful to
astronomers and geographers : the confident tone in which our
illustrious author asks, What astronomer will dare to answer to
10 seconds for the accuracy of an observation, which he shall

• Im. observes lh 37' 41" Em. observes. .. . 5l> 7' 7"

1 41 15 5 8 60

1 41 17 . 5 II 22

220 Mr. South on the Eclipses of [March,

deem made under the most favourable circumstances, cannot be
read without making a deep impression on the mind of the
reader. We must, however, remember, that these sentiments
were founded upon comparison of all the observations of eclipses,
which had been made from the year 1662 to the year 1802 ; and
there will be little difficulty in believing that the chaotic mass
would fully justify the assertion ; for among the earlier obser-
vations immense discordancies would naturally be found ; but I
feel little hesitation in saying, that the observations which have
been made since the year 1802 would be far more than sufficient
to entitle the accuracy of the assertions, as far as they relate to
modern observations, not only to be disputed, but even to be
disproved. Observations made during 100 years at Greenwich
and Paris, did not determine the difference of the two meridians
nearer than 10 seconds. But observations made during seven
months in Blackman-street and at Bushey, gave the difference of
longitude to 17 hundredths of a second.

2. In a table which will be given presently, there are three
observations of the third satellite, each coming far within two or
three minutes of the truth ; we shall also produce observations
of eclipses of the fourth, liable to infinitely less error; hence
I cannot coincide with our author, in the justice of his remarks.

3. From the recorded observations of immersions and emer-
sions of the- fourth satellite, it is evident enough that the incon-
gruities are considerable ; and if examined, as our own will
hereafter be, they are found irreconcilable ; hence supposing the
same observers, the same instruments, and the same weather,
at each station, both at the immersion and emersion, we may
safely infer, that the telescopes were long and unmanageable ;*
and consequently would afford results inconsistent not only with
each other, but with themselves.

4. As to the immense discordancies between the observations
of the same eclipse related in the last paragraph ; they do indeed
place the observers and their instruments in the back ground ;
for it would be difficult to account why the observed periods of
immersion or emersion should differ more than the time which
the satellite requires to travel through a portion of space, equal
to its own diameter.

On consideration of these passages then, I am induced to
apply the sentiments they convey, more to the earlier observa-
tions, than to those of modern date ; still there can be no doubt
but that an immense quantity of the latter will be necessary, to
invalidate the monstrous inaccuracies of the former. An obser-
ver, however, of the present day, will, 1 think, let his respect for
the name of Delambre be great as it may, have some difficulty
in supposing, that similar incongruities would attend observa-
tions of similar phenomena, now that telescopes are better made,
and what is almost of as much importance, better mounted.

• When it is known that they were from 1 5 to 20 feet in focal length, there will be
some difficulty in arriving at any other conclusion.

1824.] Jupiter's Third and Fourth Satellites. 221

That observations of eclipses of the fourth satellite, are the
most incongruous it would be silly to doubt, and unless the
immersion and emersion can be procured, they cannot without
much difficulty be brought to bear, upon any useful point. The
difference of the telescopes employed will alway need a correc-
tion ; this may indeed be found by previous comparisons at the
same stations ; but as the dissimilarity of the weather at the
places of observation will materially influence the results, when
only the immersion or emersion be observed, an equation is
wanting, not so easily to be found. Fortunately, however, the
immersions and emersions of this, and the third satellite, are occa-
sionally observable within a space of time little more than two
hours ; let us, therefore, inquire a little into this matter.

We have already noticed that the fourth satellite having
entered the shadow, is a very considerable time before it becomes
lost in it ; hence its disappearance will be extremely gradual ;
let us suppose that during this time it passes through three dis-
tinct gradations of lustre ; that at the first, it resembles the small
star of { Ursse Majoris ; at the second, the small star of Polaris ;
and at the third, the small star of a Lyra. Let us then have three
telescopes ; the one able only to show the small star of £; the
second only that of Polaris ; the third adequate to show the
small star of a. Lyra. On a fine night, all the telescopes show
their respective objects very well — say at 10 o'clock ; provided
the stars have considerable altitude, and the weather be equally
good, why should they not show them equally as well at 12
o'clock ? it would puzzle most persons, I think, to determine 5 if
so, provided the analogy hold good, why may not the evanes-
cence, and re-appearance of the fourth satellite be observed,
within reasonable limits? I confess I see no reason. I know it
is said, an observer will have an impression left on his mind, that
the satellite continues visible when it really is not so ; but this
is not distinctly proved ; and again on the emersion, knowing
the point at which he is to look for it, he thinks he sees it ear-
lier than he actually does ; this again is not proved : we will,
however, allow them both, and we shall be as if they were not
allowed at all. The only difference between the three telescopes
would be, that A would give the immersion earlier than B ; and
B sooner than C. And at the emersion, A would show the satel-
lite Inter than B, and B later than C ; circumstances, as we shall
hereafter see, not of the least importance.

Entertaining then sentiments such as these, I determined on
the first favourable opportunity, to observe the immersion and
emersion of the fourth satellite, with every possible care ; and the
first day of the present month enabled me to do so. Jupiter's
meridian altitude was about 62° ; the immersion occurred when
the planet was l 1 ' 34' east of the meridian ; the emersion when
it was 34 minutes west of it. The memoranda relative to the
observations, as entered in the Journal at the time are as follow :

222 Mr. South on the Eclipses of [March,

" Prior to taking the transit of Aldebaran, the five feet equa-
torial was placed upon Jupiter, and immediately after the transit
had been secured, I went to see how matters were going on ; the
fourth satellite was at this time about the splendour of a star of
the ninth magnitude, and of a light blue colour. The night was
remarkably clear ; I determined to remain at the instrument as
long as the satellite continued visible, which, according to the
Nautical, would be at least a quarter of an hour. To make my-
self comfortable, therefore, I placed some blocks of wood upon
the double steps, and took my seat very quietly : the lights,
except that at the clock, were all put out ; it continued diminish-
ing in lustre till 4 h 34' 57" per clock, at which time I could see it
no more. I observed it of the brightness of the small star near
a. Lyrae for more than a minute.

" Emersion of the fourth satellite (observatory darkened as
before) at 6" 43' 5" per clock.

" At 6 h 45' about as bright as the pole star.

" At 6 h 52' had not half the splendour of the dullest of the
other three which were visible. Unable to spare more time,
further observation was given up."

Greatly satisfied with my own observations, I was in hopes
that the extraordinary fineness of the night would have rendered
correspondent ones, at various stations, almost certain ; but in
this I have had the mortification to find myself disappointed.
The only observer who, as far as I have ascertained (and I have
made very extensive inquiry), was similarly engaged with myself,
is to be found in Col. Beaufoy : it is however indeed fortunate
that it was he. My opinion of his observations of the eclipses
of Jupiter's satellites, has long been before the public ; so that
I cannot now be suspected of commending his accuracy, merely
to suit my present purpose.

My observations made with the five feet equatorial, the object
glass of its telescope has 64 inches focus, and 3f inches clear
aperture; power 133.

Gol. Beaufoy's telescope has an object glass, precisely of the
same diameter, but of 56*5 inches focal length : it is mounted
on a very steady stand, but not equatorially. Magnifying power
used = 86.

Prior to observation, he excluded all light from his observatory,
except what was sufficient to enable him to distinguish the hands
of his clock.

Longitude of Blackman-street observatory . . . = 0' 21-76" W.

Bushey = 1 20-93 W.

Diff. of long. Bushey to the W = 59-17

Blackman-street Observations. Bushey Observations.

Immersion 4" 35' 3-89" Immersion 4 h 32' 27-09"

Emersion 6 43 11-89 Emersion 6 43 50-46

(Sidereal time at each station.)

1824.] Jupiter's Third and Fourth Satellites. 223

Now if we add the difference of longitude to the Bushey obser-
vation of immersion, we shall have in Blackman-street time, the
instant at which the phenomenon was observed at Bushey ; and
the difference, if any, between this and the Blackman-street
observation, will show the time by which the satellite was seen
longer, at one station than at the other.

4 h 32' 27-09" = Immersion at Bushey.
+ 59*17 = Difference of longitude.

4 33 26*26 = Blackman-street time when the immersion

was observed at Bushey.
4 35 3*89 = Immersion at Blackmaa-street.

-f-1 37*63 = the time that the satellite was seen longer at
Blackman-street than at Bushey.

A mere inspection of the times shows, that the differences are
totisiderable : let us see if they are reconcileable. As the tele-
scopes at the two stations are nearly similar ; as the same pre-
caution of excluding adventitious light was employed at both ;
we must seek for the cause of the discrepancy, either in a dearer
atmosphere atone observatory than at the other — in a greater sen-
sibility to minute pai tides of light, which one observer has than
the other — or in the superior steadiness of the one instrument
over the other. As to difference of atmosphere, we have no
proof that there was any ; indeed the probability is in favour of
Bushey ; it being situated far from any frequented neighbour-
hood ; while the Blackman-street observatory is surrounded by
buildings in every direction. As to increased sensibility to small
particles of light, we have no good grounds to suspect that one
observer possesses this, more than the other. Hence we are left
to the only remaining source of discrepancy, namely, the greater
steadiness which one instrument has than the other; and this
there can be no doubt the Blackman-street instrument possesses :
itcanbe moved in right ascension by the finger and thumb ; astar
may be kept bisected by one of its micrometer wires any reason-
able time ; nor will any tremulous motion be communicated to
the star, although a power of 500 or 600 be employed. Hence
the experience of daily observation would authorize us to declare,
cateris paribus, that in Blackman-street the immersion ought to
be seen later than at Bushey : perhaps also the trifling difference
of focal length and magnifying power of the Blackman-street
instrument may contribute some little to the result ; which is,
that the immersion was seen later in Blackman-street than at
Bushey by 1' 37*63."

But if our reasoning be correct, the emersion should be seen
earlier in Blackman-street ; and if the weather at the emersion
be the same at each station, as it was at the time of immersion,
by as much as the immersion was seen later in Blackman-street,

224 Mr. South on the Eclipses of [March,

should the emersion be seen earlier ; a little allowance being
made for error of observation : let us see if it were so.

6 h 43' 50-46" = Emersion at Bushey.
+ 59*17 = Difference of longitude.

6 44 49*63 = Blackman-street time when the emersion was

observed at Bushey.
6 43 11*89 = Emersion at Blackman-street.

— 1 37*74 = the time that the satellite was seen earlier at
Blackman-street than at Bushey.

Hence it appears that the emersion was seen earlier in Black-
man-street than at Bushey ; and by an interval of time agreeing
with that by which the immersion was observed later, to 1 1 hun-
dredths of a second.

Let us now see how far the results can be converted to prac-
tical utility — to what degree of accuracy then, will they enable
us to determine the difference between the meridians of the two
observatories.

Im. at Blackman-street = 4 h 35' 3-89"
Bushey = 4 32 27*09

Hence diff. of longitude = 2 36*80 Bushey to the W.

Em. at Blackman-street = 6 h 43' 11-89"
Bushev = 6 43 50-46

Hence diff. of longitude = 38*57 Bushey to the E.

Now + 2' 36*80" or W.
- 38-57 or E.

2)+ 1 58-23 W.

Difference of longitude =0 59*11 Bushey being to W.

But known difference =0 59- 1 7

Error of observation = 0-06 at the two Stations.

Consequently the difference of longitude, between the two
observatories of Blackman-street and Bushey, is ascertained to
six-hit ndredt lis of a second ; a quantity therefore which we must
consider, as the error of observation at the two stations.

But some time since, the difference of the two meridians was
found by the same observers, with the same instruments, and the
results will be shown in the following table : —

18Q4.] Jupiter's Third and Fourth Satellites. 225

Difference of Longitude of my Observatory and Col. Beaufoy's,
by Observations of\4 Eclipses of Jupiter's Satellites, made at
our respective Stations.

My Observations.

Col. Beaufoy's
Observations.

Difference of
Longitude.

1821.

Aug. 4

Irani. 2 Sat.

ll h

5' 26- 80"

ll h

4' 31"

0' 55 80"W

18

Irani. 1

12

8-09

11

58 53

1 15-09

Oct. 24

Em. 3

10

35 8-40

10

34 22

46-40

28

Imm. 1

9

10 40-76

9

9 51

49-76

Nov. 4

Em. 1

11

6 40-83

11

5 19

1 21-83

20

Em. 1

9

25 26-26

9

24 34

52-26

27

Em. 1

11

21 4-56

11

20 19

45-56

29

Em. 1

5

49 53-60

5

49 13

40-60

29

Em. 3

6

42 49-03

6

42 8

41-03

Dec. 6

Em. 1

7

45 55-10

7

45 20

35-10

1822.

Jan. 14

Em. 1

6

23 40-48

22 27

1 13-48

29

Em. 2

6

55 45-30

6

54 15

1 30-30

Feb. 23

Em. 3

7

8 26-90

7

7 13

1 13-90

March 1

Em. 1

6

57 36-60

6

56 27

1 9-60

Mean differ, of long, of the two Observatories . . = 59-34
Known difference of the two Observatories . . . . = 69' 17
Error of observation at the two Stations =0 0*1 7

Thus it seems that 14 observations, nine of the first satellite,
two of the second, and three of the third, gave the difference of
longitude to seventeen-hundredths of a second, and that it was
the work of seven months ; while in the observation before nar-
rated, the accuracy is three times as great, and is obtained in a
few minutes more than two hours. Some perhaps will contend,
that this accuracy is the offspring of accident ; it is however at
least as probable, that accident has had nothing at all to do with
it ; on the same supposition, and with equal plausibility, might it
be urged that accident has prevented accuracy in each of the
14 observations, principally of the favourite satellite; the two
nearest of which to accuracy, are 50 or 100 times more remote
from it, than are the results of those observations, which are the
immediate objects of this communication.

From this however let it not be supposed, that I imagine
equal accuracy will always be procured ; an observer may and
occasionally does obtain the right ascension of a star by one
wire of his transit instrument just as correctly as if he employ
the five or the seven; yet he must not suppose he will .always do
it; just so with the observations of immersion and emersion I
have alluded to; all I contend for is, provided the same care —
the same instrument — the same magnifying power— the same

New Series, vol. vn. Q

226 Ellipses of the Third and Fourth Satellites. [Mahch,

precaution — the same observer — the same weather — be used,
found, or employed, at the various stations both at the immer-
sion, and subsequent emersion, that the results so far from
meriting obloquy, will probably be far more accurate than
any two eclipses of either the first or second satellites — and if
what be stated prove true of the fourth satellite, it cannot be
otherwise of the third.

But in the instance we have dwelt upon, only two observers
were concerned ; further observations therefore should be re-
curred to — those then whose stations relatively to Green-
wich are well settled — whose instruments are well mounted, and
whose time is well known, will do an essential service to prac-
tical astronomy, by observing the immersions and subsequent
emersions of the third and fourth satellites whenever they are
visible — they should be at their telescopes some eight or ten
minutes before the phenomena are expected ; should take every
possible care that the immersion and emersion be observed
under similar circumstances — and should note at the time, how
far the weather at the emersion coincided with that in which
the immersion was observed ; nor will the relative splendour of
such other satellites, as may be visible at the two periods, allow
an accustomed eye much difficulty in deciding.

I have dwelt upon this subject perhaps longer than some will
say, its importance warrants — two marked instances of the
injurious effects of the opinions generally entertained against
observations of the fourth satellite have however recently presented
themselves — One individual many years an accurate and assiduous
observer assures me, that in consequence of prejudice, he never
looked out for an eclipse of the fourth satellite in his life. — And
another astronomer did not observe the very eclipse here so
often referred to, "because of sentiments he entertained founded
on Delambre's statements." — Nor are the individuals referred to
of any mean importance — the latter is well known as the author
of many useful astronomical publications ; whilst to the former,
practical astronomy owes greater obligations, than to any person
in existence.

To remind observers a table is subjoined giving in sidereal
and mean time the predicted immersions and emersions of the
third and fourth satellites during the next two months, and should
the weather prove favourable, I have little doubt the result
will show; that the opinions generally entertained of the inutility
of observations of eclipses of the Third and Fourth satellites,
originate in PREJUDICE, and terminate in ERROR.

Sidereal Time. Mean Time.

March 2. Immersion third satellite . . 8 h

Emersion 11

April 8. Immersion fourth satellite . . 9

Emersion 12

It is almost needless to say that where the satellite is lost at
the immersion, it may be looked for at the emersion.

James South.

0'

9 h

18'

13

12

30

13

8

4

6

10

58

1824.] Analyses of Books. 227

Article XIV.

Analyses of Books.

Philosophical Transactions of the Royal Society of London, for

1823. Part II.

(Continued from p. 147.)

XXI. Second Part of the paper on the Nerves of the Orbit. By-
Charles Bell, Esq. Communicated by Sir Humphry Davy, Bart.
Pres. RS.

The following extract from the concluding pages of this paper,
gives the general results of Mr. Bell's investigation of the nerves
of the head.

" I hope I have now unravelled the intricacy of the nerves of
the head, and have correctly assigned to each nerve its proper
office. In our books of Anatomy, the nerves are numbered
according to the method of Willis, an arrangement which was
made in ignorance of the distinct functions of the nerves, and
merely in correspondence with the order of succession in which
they appear on dissection.

" The first nerve is provided with a sensibility to effluvia,
and is properly called olfactory nerve.

" The second is the optic nerve, and all impressions upon it
excite only sensations of light.

" The third nerve goes to the muscles of the eye solely, and
is a voluntary nerve by which the eye is directed to objects.

" The fourth nerve performs the insensible traversing motions
of the eyeball. It combines the motions of the eyeball and
eyelids, and connects the eye with the respiratory system.

" The fifth is the universal nerve of sensation to the head and
face, to the skin, to the surfaces of the eye, the cavities of the
nose, the mouth and tongue.*

" The sixth nerve is a muscular and voluntary nerve of the

e y e -

" The seventh is the auditory nerve, and the division of it,
called portio dura, is the motor nerve of the face and eyelids,
and the respiratory nerve, and that on which the expression of
the face depends.

* " In this view of the fifth nerve, I have not touched upon its resemblance to the
spinal nerves. But if we had ascended from the consideration of the spinal nerves to
the nerves of the head, we should then have seen that the fifth was the spinal nerve of
the head ; that it had a ganglion at its root, a double origin, and from its power over
the muscles of the jaws and mastication, that it was a double nerve in function, being
that nerve which bestows sensibility, at the same time that it sends branches to the
original muscles ; that is to say, to that class of muscles which are common to animals
in every gradation. In all these respects it resembles the spinal nerve*."

q2

228 Analyses of Books. [March,

" The eighth, and the Accessory nerve, are respiratory nerves.

" The ninth nerve is the motor of the tongue.

" The tenth is the first of the spinal nerves ; it has a double
root and a double office ; it is both a muscular and a sensitive
nerve.

" Had I taken the nerves of any other complex organ rather
than of the eye, I should have had an easier task. If I had
taken the nerves of the tongue, I should have been able to prove
by experiment, and in a manner the most direct, that the three
nerves belong to three distinct functions, and stand related to
three different classes of parts. I could have shown that taste
and sensibility belong to the office of the fifth nerve, voluntary
motion to the ninth, and deglutition to the glossopharyngeal
nerve of the tongue."

XXII. An Account of Experiments made with an Invariable
Pendulum at New South Wales by Major-General Sir Thomas
Brisbane, KCB. FRS. Communicated by Capt. Henry Kater,
FRS. in a Letter to Sir Humphry Davy.

The following are the results of these experiments, as given by
Capt. Kater: —

" If the number of vibrations resulting from Sir Thomas Bris-
bane's experiments at Paramatta be compared with the mean
number of vibrations made by the pendulum at London, we shall
have 39*07696 inches for the length of the pendulum vibrating
seconds at Paramatta; •0052704 for the diminution of gravity

from the pole to the equator ; and ■■ for the resulting com-

pression ; the length of the pendulum vibrating seconds at Lon-
don being taken at 39*13929 inches.

" The experiments at Paramatta being compared with those
made by me at Unst, in latitude 60° 45' 28" north, give -0053605
for the diminution of gravity from the pole to the equator, and

- ■ for the resulting compression.

" If Mr. Dunlop's experiments at Paramatta be compared
with those made at London, we obtain 39-07751 for the length of
the seconds' pendulum at Paramatta, -0052238 for the diminution

of gravity from the pole to the equator, and ^^ for the com-
pression. Or, comparing Mr. Dunlop's experiments with those
made at Unst, we have -0053292 for the diminution of gravity

from the pole to the equator, and ^-^- for the resulting com-
pression.

" The compressions here deduced must not as yet be deemed
conclusive ; for it is well known that a very small alteration in
the number of vibrations made by the pendulum would occasion
a considerable difference in the fraction indicating the compres-
sion. The indefatigable zeal of Sir Thomas Brisbane will, how-
ever, no doubt soon furnish additional data."

1824.] Proceedings of Philosophical Societies. 229

" P. S. I may here take the opportunity of correcting an
error in the " Account of Experiments for determining the
Variation in the Length of the Pendulum vibrating Seconds at
the principal Stations of the Trigonometrical Survey of Great
Britain."

" In the first series of observations made with the repeating
circle for the latitude of Clifton, 1' 41'6" has been applied as the
correction for the level instead of 141*6" = 2" 21-6". The
resulting latitude, when the proper correction is made, is
53° 27' 44-94" instead of 53° 27' 4094", and the greatest differ-
ence between the five independent latitudes of Clifton 3-48"
instead of 5-24"."

XXIII. On the Daily Variation of the Horizontal and Dipping
Needles. By Peter Barlow, Esq. FRS.

An abstract of this paper will be found in the present number
of the Annals, at p. 163.

XXIV. On the Diurnal Deviations of the Horizontal Needle
whenunder the Influence of Magnets. By Samuel Hunter Chris-
tie, Esq. MA. Fellow of the Cambridge Philosophical Society:
of the Royal Military Academy. Communicated by Sir Hum-
phry Davy.

Our present limits will not permit us to give any account of
this extended paper, occupying 50 pages ; but we shall probably
devote a separate article to that purpose.

XXV. On Fossil Shells. By Lewis Weston Dillwyn, Esq.
FRS. In a Letter to Sir H. Davy.

This paper we have reprinted entire at p. 177

(To be continued.)

Article XV.

Proceedings of Philosophical Societies.

KOYAL SOCIETY.

Jan. 15. — Messrs. J. H. Vivian, and Michael Faraday, were
respectively admitted Fellows of the Society; and the reading
of Messrs. Herschel and South's " Observations on the Posi-
tions and Distances of Three Hundred and Eighty Double and
Triple Fixed Stars," was resumed and concluded.

Jan. 22. — Dr. C. Scudamore was admitted a Fellow of the
Society ; and the following paper was read :

" On a Mode of preventing the Corrosion of Copper-Sheath-
ing, by Sea-Water, in Ships of War, and other Ships." By Sir
Humphry Davy, Bart. PES.

The attention of the President having been drawn to this sub-
ject by the Commissioners of the Navy Board, he instituted a

230 Proceedings of Philosoph ical Societies. [March,

series of experiments upon it, and has discovered a simple and
effectual mode of remedying the evil. Copper, when immersed
in sea-water, however pure and malleable it may be, becomes
covered with a coat of a green submuriate, a sort of rust, which,
when washed off, is succeeded by a similar one, and the process
continues until the metal is completely destroyed.

It was evident that no alteration which could be effected in the
copper would prevent its corrosion ; the effect on different kinds
of copper might be somewhat different, but the principal diver-
sities must be owing to the variations in the saltness and tem-
perature of the sea-water.

Sir Humphry was led to the discovery, by the same principle
which led him to that of the decomposition of the alkalies ;
namely, that chemical affinities might be balanced or destroyed,
by changing the electrical states of the substances : it thence
appeared that the corrosion of the copper might be prevented by
its being brought, by contact with another metal, into a nega-
tively electric state ; and he had accordingly found that by the
contact of tin, forming part of an electrical circuit, of T ^th part
the surface of the copper, the desired effect was completely
obtained. Other metals, positive in respect to copper, may be
employed, as lead and zinc, but tin is preferable, on account of
its capability of being brought into complete contact with the
copper, by means of solder, and also because its submuriate is
easily detached from the metal.

The experiments were made with ribbands of tin, and it was
found that such a ribband, equal in substance to only -5-g-oth part
of the copper, effectually prevented the corrosion of the latter.
They were so entirely satisfactory, that not the smallest doubt
can be entertained of the perfect success of the method in prac-
tice ; and the Lords Commissioners of the Admiralty have made
arrangements for enabling the President to repeat them on the
largest scale, on ships of war.

It is probable, Sir Humphry observes, that this method, besides
preventing oxidation, will also prevent the adherence of vegeta-
bles and marine animals to the sheathing.

This interesting communication terminated with some allusions
to the great importance of the discovery it announced, in a
national point of view, with respect to our maritime and commer-
cial interests.

The reading was likewise commenced of a paper, " On the
Development of Magnetical Properties in Iron and Steel by
Percussion, Part II." By W. Sc.oresby, Jun. FUSE. Commu-
nicated by Sir H. Davy.

Jan. 29. — Thomas Amyot, Esq. VPSA. was admitted aFellow
of the Society, and the reading of Mr. Scoresby's paper was ter-
minated.

This communication was a continuation of a former paper by
Mr. Scoresby, under the same title, which appeared in the Phil.

1824.] Royal Society. 231

Trans, for 1822. (See Annals,^. S. v.) In the first part, Mr. S. de-
•cribes his new process for the development of magnetism, and

fives the result of a number of experiments made with different
inds of iron, and under different modes of treatment. The only
experiments at all analogous to these were performed by Dr.
Gilbert about two centuries back, in which Dr. G., hammering
a piece of iron in the direction of the magnetic meridian, and
drawing it out while red-hot, gave it such a degree of magnetism
as to cause it, when floated by a piece of cork on water, to
adjust itself in a north and south direction. But Dr. Gilbert
went no further. Mr. Scoresby, however, considering, that as
magnetism in steel is more readily developed by the contact of
magnetizable substances, and particularly if these substances be
already magnetic, imagined, " that the magnetizing effects of
percussion might be greatly increased by hammering a steel bar
with its lower end resting upon the upper end of a large rod of
iron or soft steel, both the masses being held in a vertical posi-
tion ; and that if the rod were first rendered magnetic by ham-
mering, the effect on the steel bar would probably be augmented."
The experiments instituted to ascertain the effect of such treat-
ment fully proved that these opinions were correct. A small bar
of soft steel being hammered while resting upon a surface of
stone or metal, not ferruginous, was rendered capable of lifting
64 grains of iron, which was the extreme effect ; but on
being hammered while held vertically upon a parlour poker, also
held erect, it lifted a nail of 88 grains weight after 22 blows.

The paper now communicated to the Royal Society described
a new arrangement and process, by which a much higher degree
of magnetic energy was developed. In the former experiments
of Mr. Scoresby, a single rod of iron only was used, and the
steel bars or wires were hammered upon it, while both were
held in a vertical position ; in which case the magnetism of the
iron, after hammering, was employed in aid of the power of per-
cussion for the development of the magnetism of the steel bars.
But the iron acted only on the lower end of the steel wires ; the
magnetism of the upper end being spontaneous, or what is by
magneticians called consequential. Hence, Mr. S. attempted to
supply an additional force for the development of the magne-
tism of the steel, to act upon the upper end of the wire as well
as on the lower, and this ne accomplished by hammering the
wire or bar of steel between two bars of iron. The bars of iron
he used were three feet and one foot in length, both made of
common iron. The steel consisted of wires of about one-eighth
of an inch in diameter. The lifting power produced in the wires
was estimated by the heaviest of a series of nails, polished at
the points, which the wire was capable of lifting.

We cannot follow Mr. Scoresby through the details of his
experiments ; but we may state a few particulars of the results
which he obtained from his investigations.

232 Proceedings of Philosophical Societies. [March,

1. By Mr. Scoresby's first process (which he denominates the
simple process, to distinguish it from the second, or compound
process), he obtained a maximum magnetical effect on a steel
wire of about six inches long, capable of lifting a nail of 186 grs.
which effect the compound process raised up to 326 grs. In
other cases, an equal and sometimes a superior effect was pro-
duced.

2. In respect of temper or degree of hardness of the wires, it
was found that the softest wires obtained generally the highest
power, and were most easily magnetized, but the effect °soon
went off".

3. By using a larger bar of iron (about eight feet in length), a
great increase of magnetical power was obtained, a wire of only
six inches long being made to lift, by hammering by the com-
pound process on this bar, a weight of 669 grains, or four times
the weight of the wire.

4. The limit to the magnetism given to the wires, Mr. Scoresby
considers to be determined by the magnetism of the iron bars
employed. The bars being simply placed vertically, become
slightly magnetic by position from the earth. This polarity is
increased by hammering them while they remain in a perpendi-
cular position. An increase of magnetism continues to obtain
by repeated hammering the bars up to the extent that Mr.
Scoresby developed. But the maximum required the bars and
wires to be very often hammered, and the process to be conti-
nued at intervals for a few minutes at a time, during several
days. For a wire, however, to be made to lift its own weight
required only a few minutes hammering, and when the bars had
become magnetic by use, a single blow with a hammer was
sometimes found sufficient to enable the wire to lift its own
weight. To produce the best effect, it is important to have the y
steel wires polished at the end, and always to use the same end
downward, which obtains north polarity; for by this means, Mr.
S. found that an increase of capacity for magnetism in the wires
took place after almost any operation.

Mr. S. conceives that the high effect obtained by percussion
depends on the disposition that percussion gives to the ferrugi-
nous particles, for assuming that condition to which we apply
the name magnetic. The particles of ferruginous substances,
especially steel, resist this condition to a certain extent, which
resistance percussion tends to overcome. The general law Mr.
S. resolves into this ; that percussion on magnetizable substances
in mutual contact inclines them to an equality of condition. And
this effect he illustrates, by the tendency of bodies unequally
heated, to assume, when placed together, the same temperature.
And from the tendency of the cooler bodies to acquire tempera-
ture, and the hotter to lose temperature, he explains the appa-
rently opposite proposition, that magnetism is both developed
and destroyed by percussion. The power of strong magnets J6

1824.] Royal Society. 233

diminished by hammering, if held in the air unsupported, or
rested upon any body not equally magnetic ; and the power of
very weak magnets, or bars with little or no magnetism, is
increased, if held upon any substance that is magnetic. In all
cases and circumstances, the hammering tends to bring the sub-
stances in contact into a similar state, the weaker being
strengthened, and the stronger weakened.

A paper was also read, entitled " Observations on the Iguana
tuberculata, the common Guana." By the Rev. Lansdown
Guilding, BA. FLS. Communicated by Sir E. Home, Bart.
VPRS.

This paper was very short : it commenced with some general
remarks on the necessity, in zoology, of describing animals from
living specimens, and on the errors which had been committed by
naturalists in stating the characters of certain lizards, in conse-
quence of inattention to that circumstance ; thus the gular pro-
cess of the lizards alluded to, had been erroneously described as a
pouch capable of dilatation. Mr. Guilding then proceeded to
describe briefly an organ on the parietal bones of the head of the
guana, to which he gave the name of foramen Homiamim, in
honour of Sir E. Home.

Feb. 5. — A paper was communicated, entitled, " A finite and
exact Expression for the Refraction of an Atmosphere nearly
resembling that of the Earth." By Thomas Young;, MD. For.
Sec.RS. J

The reading was commenced of the Bakerian Lecture, by
J. F. W. Herschel, Esq. FRS.

Feb. 12. — The Bakerian Lecture was concluded.

The subject of this Lecture is the phenomena exhibited by
mercury, and other fluid metals, when placed within the in-
fluence of an electric current transmitted through conducting
liquids.

If a quantity of mercury be placed in a dish and covered
with a conducting liquid, through which an electric current is
transmitted from a voltaic pile of moderate energy, by wires not
in contact with the mercury, this metal will be thrown into a
state of circulation, the force and direction of which varies
with the nature of the liquid, the intensity of the electric
power used, and other adventitious circumstances. If the liquid
be sulphuric, phosphoric, or any of the more concentrated acids,
the circulation is excessively violent, even with weak electric
powers, and takes place in a directiony)w» the negative to the
positive wire. On the other hand, under alkaline solutions,
pure mercury remains at perfect rest in like circumstances ;
but if the least atom of potassium, sodium, zinc, or any metal
more electro-positive than mercury, be added to it, a violent
rotation is immediately produced, in the opposite direction,
or from the positive wire. From some trials, Mr. Herschel is led

234 Scientific Intelligence. [March,

to conclude, that much less than a millionth part of potassium,
or a 100,000th of zinc, is sufficient to impart this singular
property to mercury. Lead and tin act with much less energy.
Bismuth, copper, silver, and gold, not at all. A number of
singular phenomena in the electrization of mercury and other
metals are described ; and some calculations added respecting
the intensity of the forces acting on the molecules of the
electrified body, which Mr. H. concludes, in his experiments,
to have been not less than 50,000 times their gravity.

In the sequel, Mr. Herschel notices the curious gyratory
motions, observed by M. Serrulas, in fragments of alloy of
potassium and bismuth, when floated on mercury under water;
the cause of which he shows to have been misunderstood by
Mr. S. and which admit of easy explanation on the principles
of this Lecture.

For the sake of such of our readers as may wish to repeat
these experiments, we may mention, that it is absolutely neces-
sary to use mercury recently distilled and purified, by washing
with dilute nitric acid, and that all the vessels employed must
be scrupulously clean, and the surface of the metal free from
any adhering film. A small battery of eight or ten pairs of
single plates is sufficient to exhibit all the phenomena.

Article XVI.

SCIENTIFIC INTELLIGENCE, AND NOTICES OF SUBJECTS
CONNECTED WITH SCIENCE.

I. Primary Forms of Sulphur.

Our readers may have remarked in the present volume of the Annals,
a description by Mr. Brooke, of two primary forms of sulphate of
nickel. A paper appears in the Annales de Chimie, for Nov. 1823, by
Mr. Mitscherlich, announcing the discovery of two primary forms
of sulphur. The one, that which occurs in nature, an octahedron
tvith a rhombic base ; the other, an oblique rhombic prison, P. on M.
measuring 9*° 5' and M. on M. 90° 32', produced by fusing sulphur
in a vessel, in which it may very gradually cool ; when a crust is
formed round the mass, it is to be broken, and the sulphur which
remains fluid to be poured out ; the crystals will appear lining the
cavity.

Mr. M. appears to consider that all substances which produce
crystals, may likewise assume two primary forms.

This gentleman has crystallized phosphorus from a solution of
phosphuret of sulphur, the form of which is the rhombic dodecahe-
dron.

1824.] Scientific Intelligence. 235

II. Uranite of Autun.

M. Laugier has submitted the uranite of Autun to a fresh examina-
tion ; the results are :

Water 21-0

Oxide of uranium 550

Phosphoric acid 14v5

Lime 4?"6

Oxide of iron and silica 3'0

Traces of manganese and tin.

98-1

From this analysis M. Laugier draws the following conclusions :

1st, That the uranite of Autun, hitherto considered either as an
oxide of uranium, or as a compound of the oxide of lime, is a true
phosphate of uranium.

2dly, That the lime in this mineral, is for the most part, in an un-
combined state.

3dly, That phosphate of uranium is entirely soluble in carbonate of
ammonia, from which it is totally precipitated by ebullition. —
(Annales de Chimie et de Physique, vol. xxiv. p. 247. Nov. 1823.)

The existence of phosphoric acid in the ore of uranium was an-
nounced by me, in the Annals for December 1822. I then supposed,
though erroneously, that the fact was new, but it had been entirely
overlooked. In the Annals for January 1823 (p. 61), I stated, precisely
the same opinion of the real nature of the uranite of Autun, as
M. Laugier has announced, that it is " essentially composed of phos-
phate of uranium."

M. Laugier fairly acknowledges that he had heard of the fact of
the phosphoric acid having been noticed in England, but only since
the reading of this paper on the 15th of September last. — Edit.

III. Phosphorescence of Acetate of Lime.

(To the Editor of the Annals of Philosophy.)
SIR, Jan. 14, 1824.

Not being aware that the phosphorescence of this salt has been
noticed by any chemical writer, I have taken the liberty to forward
you the observations I have made on its peculiar properties in this
respect. Dissolve any quantity of acetate of lime in water, and
place it on a sand heat, in a wedgwood ware dish, evaporate to dry-
ness without disturbing it. When quite dry, let the bulb of a ther-
mometer be rested on the bottom of the dish, and when the tempera-
ture has attained the 250th of Faht. the lime will be found to adhere
very firmly. If light be now excluded, and the acetate strongly
rubbed with a stiff spatula, it will become highly luminous. The high
temperature required for producing this appearance is peculiar to this
substance and filiate of lime. 1 am, Sir,

Your obedient servant, Nicholas Mjlls.

236 Scientific Intelligence. [March,

IV. Chemical Examination of a Fragment of a Meteor Xvhich fell in
Maine, August^ 1S23. By J. W. Webster, MD. MGS. Lond. &c.

This aerolite fell at Nobleborough in the State of Maine, on the
7th of August, 1S23, between four and five o'clock p.m. The only
information which I have been able to obtain of the attending pheno-
mena is from the papers of the day, and from a communication of
Professor Cleaveland, which is published in the American Journal of
Science, vol. vii. p. 170; this account he informs me was obtained
at his request by a gentleman of intelligence in a personal interview
with Mr. A. Dinsmore, who was at work near the place where the
aerolite struck. " Mr. Dinsmore's attention was excited by hearing
a noise which at first resembled the discharges of platoons of soldiers,
but became more rapid in succession. The air was perfectly calm ;
and the sky was clear, with the exception of a small whitish cloud,
apparently about forty feet square, nearly in his zenith, from which
the noise seemed to proceed. After the explosion, this little cloud
appeared to be in rapid spiral motion downwards, as if about to fall on
him, and made a noise like a whirlwind among leaves. At this
moment, the stone fell among some sheep, which were thereby much
frightened, jumped, and ran into the woods. This circumstance
assisted Mr. D. in finding the spot where the stone struck, which was
about forty paces in front of the place where he was standing. The
aerolite penetrated the earth about six inches, and there meeting
another stone, was broken into fragments. When first taken up, which
was about one hour after its fall, it exhaled a strong sulphureous
odour. The whole mass previous to its fracture probably weighed
between four and six pounds ; other fragments of the same meteoric
stone are said to have been found several miles distant from Noble-
borough." — Amer. Jour.

To the politeness of Dr. George Hayward I am indebted for a
fragment of this meteor.

Externally the specimen was in part covered with a thin semi-
vitrified crust or enamel of a black colour, the surface of which was
irregular and marked with numerous depressions, presenting every
appearance of having been subjected to intense heat. The crust was
hard, yielding with difficulty to the kuife. The quantity of this crust
which the small fragment I obtained afforded, was not sufficient to
allow of any separate analysis of it.

The mass of the specimen had a light gray colour interspersed
with oblong spots of white, having the aspect of decomposed leucite,
and giving it a porphyritic aspect. Throughout the stone minute
points of a yellow substance, resembling olivine, were distributed,
with microscopic points of a yellow colour, which I imagine were
sulphuretted iron. The cement by which these substances were
united was of an earthy aspect, and soft texture, readily broken down
by the fingers. The general appearance of the mass was precisely
like that of some of the volcanic tuffas.

The specific gravity was remarkably low, being but 2*05.

Before the blow-pipe it exhaled a sulphureous odour, but was not
fused.

The specimen was reduced to powder and submitted to the action
of a magnet of considerable power, but no attractable particles were
separated. A portion was heated to redness on a platina spoon ; it

1824.] New Scientific Books. 237

emitted the sulphureous odoHr, and its weight was diminished rather
more than 21 per cent.; the residue acquired a brown colour ; it wai
again presented to the magnet, but nothing was attracted.
The composition of this meteoric mass I found to be :

Sulphur 18-3

Silex 29-5

Alumina -t'7

Lime a trace

Magnesia 2-t-8

Chrome 4-0

Iron H.9

Nickel 2-3

98-5

Loss .... I'D

100-0
(Phil. Mag. Ixiii. 16—19.)

Article XVII.
NEW SCIENTIFIC BOOKS.

PREPARING FOR PUBLICATION .

C. Tennant, Esq. has in the press, in 2 vols. 8vo. a Narrative of a
Tour through Parts of the Netherlands, Holland, Germany, Switzer-
land, Savoy, and France, in the Years 1821, 1822, including a De-
scription of the Rhine Voyage in the middle of Autumn, and the Stu-
pendous Scenery of the Alps in the depth of Winter.
■ Shortly will be published, by Mr. Benecke, of Lloyd's, a Treatise on
the Principles of Indemnity in Marine Insurance, Bottomry, and
Respondentia, containing practical Rules for effecting Insurances, and
for the Adjustment of all Kinds of Losses and Averages.

Capt. Parry's Second Voyage of Discovery is nearly ready for pub-
lication.

Thomas Hewson, AB. is about to publish Observations on the His-
tory and Treatment of the Ophthalmia accompanying the Secondary
Forms of Lues Venerea.

Moscologia Britannica, containing the Mosses of Great Britain and
Ireland, systematically arranged and described; by W.J. Hooker, and
Thomas Taylor, MP. is in the press.

Mr. George Dyer is preparing " The Privileges of the University of
Cambridge."

JUST PUBLISHED.

A Selection of the Geological Memoirs contained in the Annates des
Mines, with a Synoptical Table of Equivalent Formations, in English,
French, and German, &c. With 11 Plates. 8vo. 18s.

238 New Patents. [March,

A Grammar of Infinite Forms ; or the Mathematical Elements of
Ancient Philosophy and Mythology ; by W. Howison. Post 8vo. 5s.

A Compendious View of the History of the Darker Ages ; by C.
Chatfield, Esq. 8vo. 7*. 6rf.

Prodromus Systematis Universalis Regni Vegetabilis, auctore Aug.
P. de Candolle. Part I. Thick 8vo. 1/. 5s.

Article XVIII.
NEW PATENTS.

G. M. Glascot, Great Garden-street, Whitechapel, brass-founder,
and T. Michell, Upper Thames-street, gent, for their improvements in
the construction or form of nails to be used in or for the securing of
copper and other sheathing on ships, and for other purposes. — Dec. 9.

T. Home, the younger, Birmingham, brass-founder, for improve-
ments in the manufacture of rack pullies in brass or other metals. —
Dec. 9.

W. Furnival, Droitwich, salt-manufacturer, and A. Smith, Glasgow,
master-mariner, for their improved boiler for steam-engines and other
purposes. — Dec. 9.

Sir H. Heathcote, Surry-street, Strand, for his improvement of the
stay-sails generally in use for the purpose of intercepting wind between
the square sails of ships and other square-rigged vessels. — Dec. 13.

J. Boot, Nottingham, lace-manufacturer, for his improved apparatus
to be used in the process of singing lace and other purposes. — Dec. 16.

P. J. B. V. Gosset, Queen-street, Haymarket, merchant, for produc-
ing various shapes, patterns, and sizes from metals, or other materials,
capable of receiving an oval, round, or other form. — Dec. 18.

T. Greenwood, Gildersoun, near Leeds, machine-maker, and J.
Thackrah, surgical mechanist, Leeds, for their improvements in pat-
terns and clocks. — Dec. 27.

J. Vallance, Esq. Brighton, for his improved methods of freezing
water. — Jan. 1.

F. Devereux, merchant, Cheapside, for certain improvements on the
mill or machine for grinding wheat and other articles, commonly
known by the name of the French Military Mill. — Jan. 8.

J. Foot, Charles-street, Spitalfields, silk-manufacturer, for his im-
proved umbrella. — Jan. 15.

J. White, New-road, Marylebone, architect, for his floating break-
water. — Jan. 15.

J. Finlayson, Muirkirk, Ayrshire, farmer, for certain improvements
on ploughs and harrows. — Jan. 15.

Jean le Grand, Leman-street, Goodman's-fields, vinegar-manufactu-
rer, for certain improvements in fermented liquors, and the various
products to be obtained therefrom. — Jan. 15.

W. Gutteridge, Dean-street, St. Fin Barrs, Cork, musician and land-
surveyor, for certain improvements on the clarionet.— Jan. 19.

1824.]

Mr. Howard's Meteorological Journal.

239

Article XIX.

METEOROLOGICAL TABLE.

Barometer.

Thermometer.

|

1884. Wind.

Max.

Min.

Max.

Min.

Evap.

Rain.

1st Mem.

Jan. 1 W

29 49

2946

48

36

2N W

30-31

29'49

47

32

3N W

30-60

30-31

45

28

4S W

30-62

30-39

40

28

n a<

5-S W

30-45

30-35

40

28

6' Var.

3045

30-35

40

28

7N W

3045

304+

38

30

MM

8 Var.

30-44

30-37

40

32

9S W

30-37

30-29

45

34

10S W

30-39

30-21

45

38

^^^

23

111 N

30-58

30-39

43

23

12S W

30-60

30-58

33

19

13 S W

30-60

30-53

31

23

mm —-

14JN W

30-53

30-48

31

26

15N W

30-67

30-45

36

26

16) N

30-68

30-66

36

24

17,'N W

3070

30-56"

38

24

18 N W

30-56

3038

40

31

19

W

3038

30-2S

42

36

20

N W

30-28

29-90

42

38

, ,

06

21

s w

29-90

29-43

44

38

MM

31

22

s w

2943

28-98

51

42

,

15

23

N W

29'85

2S93

48

34

24

N W

3010

29*85

50

34

., ,

25

W

3024

30-10

54

49

, „

■26

w

30-24

2999

54

41

,

27

s w

2999

29-71

54

36

__

OP

03

28

s w

29-97

2968

46

35

29

N W

30-26

29-97

42

24

30

w

30-26

30-16

38

26

31

s

3016

30-11

43

24

•87

— -. ...

3070

28-93

54

19

0-87 |

0-87

The observations in each line of the table apply to a period of twentv-four hour*,
beginning at 9 A. M. on the day indicated in the first column. A dash denotes that
tin result is included in the next following observation.

240 Mr. Howard's MeteorologicalJournal. [March.,

REMARKS.

First Month. — I. Cloudy and fine: boisterous night. 2. Fine: much wind, but
calm at sunset : the Cirrotwnulus has prevailed these two days. 3. Very fine day.
4. Little wind : a dense fog came on suddenly in the forenoon, and the day was misty
after. 5 — 9. Fine days. 10. Fair: some rain in the night. 11. Fine: cloudy.
12, 13, 14. Hoar frost, with foggy nights: a great quantity of rime gradually accumu-
lated on the trees, chiefly on the south side of the branches, presenting a magnificent
spectacle. 15. Overcast, p.m. with a little snow : the wind having risen a little, the
rime has fallen from the trees unmelted. 17. It is now winter under the trees, with a
spring-like appearance every where el*e : the afternoon actually presented the rudi-
ments of a thunder-cloud, succeeded by beautiful Cirrocumuli in bars ; amidst which
the moon rose with the calm lustre of a summer's evening. 19. Cirrocumulus above
Cirrostratus in light beds over the whole sky. 20. Cumuloslratut : after which Nimbi
and an overcast sky : wind, with some rain in the night. 2 1 . A hollow wind ; with
rain, mostly in the night. 22. Overcast : showers : in the night the wind rose, and it
blew hard towards morning. 23. Fine morning : Cirrostratus, with Cirrus aloft :
windy. 24 — 27. Overcast and cloudy. 28. Showery. 29. Fine : Cumulus, with
Cirrocumulu-s. 30. Hoarfrost: very clear at night. 31. Hoarfrost: little wind, but
with a hollow sound in the trees : very fine day.

RESULTS.

Winds : N, 2 j S, 1 ; SW, 10 ; W, 5 ; NW, 1 1 ; Var. 2.

Barometer : Mean height J

For the month 30-199 inches.

For the lunar period, ending the22d 30*119

For 14 days, ending the 6th (moon south) 29-874

For 13 days, ending the 19th (moon north) 30«483

Thermometers Mean height

For the month 36-955°

For the lunar period 37-172

For 30 dayi, the sun in Capricorn 37-150

Evaporation 0-87 in.

Rain 0-87

Results omitted by an oversight last Month.

Barometer : Mean height

For the lunar period, ending the 24th 29*979 inches

For 1 5 days, ending the 10th (moon south) 30-047

For 13 days, ending the 28d (moon north) 29-892

Theromometer :

For 30 days, the sun in Sagittarius 4 1*1 50°

Laboratory, Stratford, Second Month, 21, 1824. L.HOWARD.

ANNALS

OF

PHILOSOPHY.

APRIL, 1824.

Article I.

On Expansions, particularly on those of Glass and Mercury.
By Mr. Crichton.

(To the Editor of the Annals of Philosophy.)

SIR, Glasgow, March 10, 1824.

A thorough acquaintance with the various laws which
regulate the expansive powers of different bodies, is of such
acknowledged importance in all experimental researches, that
the most eminent scientific men of this and other countries have
their names identified with some correction, or new determina-
tion, in this branch of knowledge.

So late, however, as 1818, when MM. Dulong and Petit insti-
tuted the experiments detailed in their well-known prize memoir,
published in the 7th volume of the Annales de Chimie et de
Physique, those gentlemen, though in possession of determina-
tions by Roy, Smeaton, Deluc, Lavoisier, Laplace, and many
others, nevertheless deemed it expedient to try anew what the
expansions were of glass and mercury, as these were to form the
basis of all their after investigations.

They begin with finding the absolute dilatation of mercury.
Their method of doing this is so ingenious, that very general

reliance seems to be placed on the number they assign, — • for

the dilatation of mercury in thermic unit from the temperature
of freezing, to that of boiling water.

MM. Dulong and Petit next proceed to ascertain the appa-
New Series, vol. vii. r

242 Mr. Crichton on Expansions. [April,

rent dilatation of mercury in glass, which they effect in the usual
way, by subjecting a known weight of that fluid, contained in a
glass vessel carefully deprived of air and humidity, to the
increase of temperature in the same thermic unit ; then dividing
the weight of the quantity contained in the vessel at freezing, by
the weight of the quantity expelled by boiling, they obtain the

quotient 64*8, and thence infer, that -rr^ is the apparent dilata-
tion of mercury in glass.

These very able experimenters justly insist on the great pre-
cision of which this method is susceptible. In trials I have
made, with vessels holding from 200 to 500 grains, the capillary
opening was so small, that a quantity, corresponding to less than

— of a degree could be detached when expelled ; yet minute as

this portion is, it was very palpably noted by the balance, which

turned with y— of a grain.

Every one who knows the difficulty of obtaining tolerably
uniform results from pyrometrical measurements, will readily
admit the advantages of the method adopted by MM. Dulong
and Petit, when with them we recollect, that " dans les mesures
directes de dilatation des solides, l'incertitude se trouve triplee
en passant de l'expansion lineaire a Pexpansion en volume."
An error, however, of considerable importance has entered into
all computations from the data thus obtained, which unac-
countably remains hitherto undetected ; for, though that portion
of a fluid, detached by increase of temperature, from a glass
vessel of known volume, is indeed the fraction expelled, yet this

fraction (taking: the case of MM. Dulono; and Petit — — as " le

v ° f 64'8,

poids du mercure qui en sortait," does by no means denote the
dilatation of mercury in glass ; consequently the dilatation they
deduce as that of glass itself must be erroneous.

To illustrate this, let us suppose that a vessel, containing
64*8 parts by weight of a fluid, throws out one of those parts by
increase of temperature ; it is evident that the dilatation of that
one part has not been taken into account, for were it put into
another vessel just holding it at 32°, then would another dilata-
tion take place of - ,,„ - , of the original volume, and still with

r 419904 a

this last portion must the operation be repeated, and so on to
infinity ; the successive expansions resolving themselves into a

series, the sum of which is — -, or real dilatation. Or, to take

another view of the matter, the vessel havingbeen heated to 212°,
there will remain within 63-8 parts ; these cooled to 32° leave at
top an empty space = 1, which heating to 212° will fill up; this

one part, therefore, or 7^ of the volume of the mercury, will be

1824.] Mr. Crichton on Expansions. 243

alternately occupied by it, or vacant, as the temperature is 32°
or 212° ; so that weighing in this experiment, serves merely to
determine what parts the vessel contains at boiling.

MM. Dulong and Petit having fixed the absolute dilatation of

mercury at -rr^r, and its apparent dilatation in glass at — — , pro-
ceed to determine that of their vessel. But here an error has
been committed not less important than the other ; for in order
to obtain the dilatation in question, they adopt a common but
false assumption ; that if the absolute dilatation of a fluid, and
its apparent dilatation in a vessel be known, the difference
between these must represent that of the vessel itself, and of

course give ( — r — jr-gj gj= as the number ; the result here is

far from the truth, and would still have been so, though the

proper number — - had been used instead of — — ; the difference,

in neither case, giving the real dilatation which the vessel must
have undergone, in the interval of temperature between 32° and
212°.

To learn the true dilatation in this instance, we have only to
recollect, that whatever quantity is expelled from a vessel, by a
given increase of temperature, something more would be expelled
if the vessel itself did not expand ; and that this supposed por-
tion must be added to the quantity expelled at the higher tem-
perature (as found by experiment), and deducted from that then
remaining in the vessel, that each may represent what it would
be, if the vessel were not liable to expansion : the following
illustration will furnish a concise general formula, for all similar
dilatations of vessels.

To find this correcting quantity, we may take the coefficient
of the dilatation of the vessel to express its capacity at any given
temperature, as 32°, consequently the same coefficient, plus
unity, will express its increased capacity at the higher tempera-
ture, 212°.

Now, in the case of MM. Dulong and Petit, if g be that coef-
ficient, g and g + 1 will respectively represent the capacities at
the given extremes of temperature ; and from what is said above,

63 # 8 — — ; must be the corrected contents, as 1 H — — ; is the

true expelled quantity at 212°, then, making the former of these
divided by the latter = the coefficient of the absolute dilatation

of mercury, that is, — ^ = 55*5, we obtain g = 433*301, or
for the absolute dilatation of the vessel used by MM. Du

433-301

long and Petit, and not „— as in the table, Annates, p. 138

r2

244 Mr. Crichton on Expansions. [April,

giving, besides, for elongation of a glass rod taken as 1 at freez-
ing, — : at boiling water, instead of t-^j.

If the above reasoning be conclusive, it necessarily follows,
that the corrections for the expansion of glass, as applied to the
air and mercurial thermometers, in their after detailed experi-
ments on capacity for caloric, and the relative times of cooling,
must, to this extent, have been defective.

The fallacies which MM. Dulong and Petit have inadvert-
ently overlooked, affect not only all calculations where expan-
sion of glass should be attended to, but must have led to false
results as to the dilatations of the metals in table 4, p. 141, §ven
though the premises in the preceding page were true, viz. that
H le volume sorti represente evidemment la somme des dilata-
tions du mercure et du metal diminuee de la dilatation du verre."
Now this formula is manifestly wrong, since the volume driven
out does not represent the dilatation of the mercury, and that of
the vessel we have shown to be overrated.

By the above corrected method, the absolute dilatation of
water, from its state of maximum density at 42-3° to 212°, was

found to be ^rr. This number is greater than that generally

received ; but as 39° has sometimes been assumed as the point
of greatest density, instead of 42-3°, this circumstance, which
is in effect the same as if 45*6° had been adopted, will, to a cer-
tain extent, account for the variation.

The same method gave for the dilatation of air by the increase

of temperature from 32° to 212°, ^^ & , M. Lussac found -^^

though by means which few will think capable of minute preci-
sion. The vessel used in my trial was hermetically sealed at
the extremes of temperature ; this sealing was performed at an
opening through a capillary fibre, and to ensure complete dry-
ness, the vessel had been long heated fully to redness just before
making the experiment.

In the Memoir, MM. Dulong and Petit particularly mention,
that they found all the varieties of glass which they used, to have
the same expansive power ; this appears surprising, for 1 can
truly afhrm, that every specimen of crystal differs more or less

from another ; trials by mercury give from — - to ^r^, as the

fractions expelled, in the range from freezing, to boiling water,

even while the mercury has undergone the same rigorous and

repeated boilings, these fractions indicating elongations of glass

ii
rods, by that increase of temperature, from -^^ to y^.

That crystal which is the most colourless is commonly the
most ductile and least expansible ; but neither from its specific
gravity, nor from its tint, as seen through the axis of a tube, can

1824.] Atomic Weight of Boracic and Tartaric Acids. 245

we estimate its expansive power ; besides, it is commonly known
that tubes of every description, in course of time, become less
ductile ; hence it is not improbable, that a change takes place in
their rates of expansion.

Having been at first induced by the highly sanctioned cele-
brity of the Memoir to peruse it with a view to establish a
proper graduation of the higher part of the thermometric scale,
I may, on some future occasion, show, what that graduation
ought to be, for the degrees above 212°, and for those below
32° ; beyond which two unalterable points, no scale hitherto
laid down, gives indications corresponding to those of the
degrees within the limits of the primary thermic unit.

Besides, as it must be granted that an error exists in the
lower part of the mercurial thermometer, so must it likewise in
that filled with spirit of wine, and probably to a greater extent ;
as perhaps it has never been proved, that the expansive powers
of alcohol are, for equal increments of heat, similar to those of
mercury, particularly at the low temperatures reported by recent
navigators, as having been observed in the polar seas.

Indeed it would be no easy matter, except in climates where
very low temperatures prevail, to determine the rates of the
spirit thermometer, with reference to the mercurial one ; but to
attempt doing this by comparing the two instruments as at pre-
sent constructed, would lead only from one erroneous system of
graduation to another.

It will have been perceived that some of the expansions stated
above, are greatly less than those given by the best authors.
But as the deductions are founded on the supposition that the

absolute dilatation of mercury is really — -'; either the legitimacy

of these deductions, as now made, or the number itself, may be
called in question, if any credit be due to former determinations,
by experimenters of very high reputation.

James Crichton.

Article II.

On the Atomic Weight of Boracic and Tartaric Acids. By
Thomas Thomson, MD. FRS. Regius Professor of Chemistry
in the University of Glasgow.

(To the Editor of the Annals of Philosophy.)

DEAR SIR,

In the table of the atomic weights of chemical substances
which you inserted in the Annals for March, 1824, I perceive
that you make the atomic weight of boracic acid 275, and of

246 Atomic Weight of Boracic and Tartaric Acids. [April,

tartaric acid 8 375. These numbers being probably derived
from my experiments on these acids in the New Series of the
Annals (vol. ii. p. 131 and 138), it may be proper to state, that
by subsequent experiments I have satisfied myself that the true
atomic weights of these two acids are as follows :

Boracic acid 3*0

Tartaric acid 8*25

1. By turning to my experiments on boracic acid, you will
find that I was not quite satisfied of their accuracy. I was
anxious, therefore, to find some method which would be suscep-
tible of greater precision, and found it last summer in fluoboric
acid, which is a compound of

Fluoric acid 1*25

Boracic acid 3*0

4-25

And its atomic weight is 4*25. I had previously determined the
atomic weight of fluoric acid to be 1*25, and I knew from my
old experiments that the atomic weight of boracic acid was at
least as high as 2*75. It is obvious from this that fluoboric
acid is a compound of an atom of each of its constituents, and
consequently that an atom of boracic acid is 3.

Davy's analysis of the hydrated boracic acid must be nearer
the truth than those of Berzelius and my own. I have repeated
them again with the same result as before. No doubt some of
the boracic acid had made its escape during the application of
the heat.

2. My experiments on tartaric acid were made with the crys-
tals of that acid. I began to suspect that these crystals, which
are usually large, might contain some water mechanically lodged
between their plates. I, therefore, had recourse to tartrate of
potash, which contains no water of crystallization, and which
may be made anhydrous by exposure to a heat of about 212° for
a sufficient time. 14*25 grains of this anhydrous salt were dis-
solved in water and mixed with a solution of 2075 grains of
nitrate of lead. After the tartrate of lead had precipitated, the
supernatant liquid was tested by tartrate of potash, and by nitrate
of lead, but was not affected by either. Tartrate of lead is very
slightly soluble in water. The consequence of this is, that sul-
phate of soda when dropped into the supernatant liquid in the
above experiment occasions a sensible precipitate.

The crystals of tartaric acid contain 1 atom of water united to
1 atom of acid; hence their true atomic weight is 9*375, and
not 9*5 as I stated formerly.

I am, dear Sir, yours truly,

Thomas Thomson.

1824.] Corrections in Right Ascension. 247

Art. III. — Corrections in Right Ascension of 37 Stars of the Green-
By James South, FRS.

(Continued from j). 45.)

wicfi Catalogue.

,y Pegasi

Polaris

i Avietis

a Ceti

lAldebaran

Capcllu

Rkel

Tauri

| * Orlonia

Wean AH?

ll. in. s.

1). in. s.

It. in. s.

h. m. s.

lh. in. s.

h. in. s.

ll. 111. s.

h. m. s.

ll. 111. S-

1824. i

(J 4 11-17

58 2KS

1 57 1642

2 53 5 44 ,4 25 50-01

5 3 42-21

5 6 511

5 15 10-5-.

5 45 38 3

April 1

+ 0-52"

-41-51"

+ 0-63"

+ 0-77"

+ 1-2S '

+ 1-77"

+ 1-15"

fc 1-61"

+ 1-56"

2

5a

41-46

62

77

22

75

13

62

54

3

55

41-41

62

76

21

73

12

61

53

4

56

41-36

63

76

20

71

10

59

51

5

57

4 1 -30

63

76

19

69

09

58

50

6

59

41-25

63

75

18

67

07

56

48

7

60

41-20

63

75

16

66

06

55

46

8

61

41-15

64

74

15

64

04

53

45

9

63

41-10

64

74

14

62

02

51

43

10

64

41 04

64

73

13

60

01

50

42

11

66

40-89

64

73

12

59

00

49

41

12

67

40-75

65

73

11

57

099

48

39

13

69

40-60

65

73

10

56

98

47

38

14

70

40-46

66

73

09

54

97

45

37

15

72

40-31

66

73

08

53

96

44

36

16

73

4010

67

73

07

52

95

43

34

17

75

39-89

67

72

06

50

93

42

33

18

76

39-68

68

72

05

48

92

40

32

19

78

39-47

68

72

04

47

91

39

30

20

80

39-26

69

72

04

46

89

38

29

21

82

38-99

70

72

04

45

88

37

28

22

84

3872

71

73

03

44

87

36

27

23

86

38-45

72

73

03

43

87

35

2T

24

88

38-17

73

74

03

42

86

35

26

25

90

37-90

74

74

03

41

85

34

25

26

92

37-57

75

74

02

40

84

33

24

27

94

37-23

76

75

02

38

83

32

24

28

96

3690

78

75

0^

37

83

31

23

29

98

36-57

79

75

02

36

82

30

22

30

1-00

36-23

80

76

01

35

81

29

21

May 1

02

35-85

81

77

01

35

81

29

20

2

04

35 46

83

78

01

34

80

28

20

3

07

35-08

84

78

01

34

80

28

19

4

09

34-69

85

79

01

33

79

28

19

5

11

34-31

87

80

01

33

79

27

18

6

14

33-86

88

81

01

33

78

27

17

7

16

33-40

89

81

01

32

78

27

IT

8

18

32-95

91

82

01

32

78

27

16

9

21

32-50

92

83

01

32

77

27

15

10

23

3204

94

84

01

31

77

26

14

11

26

31-54

96

85

02

31

77

26

14

12

28

31-04

9S

86

02

31

77

26

13

13

31

30-55

100

88

02

31

77

26

13

14

34

3005

02

89

03

31

77

26

13

15

36

29-55

04

90

03

31

77

26

13

16

39

28-99

06

92

0!

31

76

2T

12

17

42

28-44

08

93

04

32

76

27

12

18

45

27-88

10

94

05

32

76

27

13

19

48

27-33

12

95

05

32

76

27

11

20

50

26-77

14

97

06

32

7 6

27

11

21

53

26-18

16

99

07

33

76

27

11

22

56

25-59

19

!•()()

08

33

77

28

II

2.'*

59

25-01

21

02

00

34

77

28

11

24

62

24-42

23

04

10

35

78

28

12

25

65

23-83

25

05

II

.'{5

78

29

12

26

67

23-18

27

07

12

36

78

29

IS

27

70

22-52

30

09

12

36

79

30

19
13

28

73

21-87

32

10

13

:<7

79

30

29

76

21-21

34

12

14

38

80

31

13

SO

79

20-56

37

14

15

39

80

31

13

31

82

19-90

40

16

16

40

81

32

18

248

Corrections in Right Ascension of

[April

Sirius

Castor

Procyon

Polluv

a Hydra

Mean AH 1

ll. in. s.

A. in. s.

1). 111. B.

h. m. $.

h. m. s.

1824. J

t> 37 23-49

7 23 21-4G

7 30 5 32

7 34 32-18

'J 18 . r iG 44

April 1

+ 1-47"

+ 2-50"

+ 2-07"

+ 2-48"

+ 2-45"

2

45

48

05

46

44

3

43

46

04

44

42

4

42

45

02

42

41

5

40

43

01

41

40

6

39

41

1-99

39

38

7

38

39

98

37

37

8

36

38

96

35

36

9

34

36

95

33

34

10

31

34

93

31

33

11

29

32

91

29

32

12

28

31

90

28

30

13

26

29

88

26

29

14

24

27

87

25

28

15

23

25

S5

23

27

16

21

24

83

22

25

n

19

22

81

20

24

18

18

20

80

19

23

19

10

19

79

17

22

20

14

17

77

15

20

21

13

15

76

13

19

22

11

14

74

12

17

23

10

12

73

10

16

24

03

11

72

09

15

25

07

09

70

07

14

26

06

07

69

06

12

27

04

06

67

04

11

28

03

04

66

03

10

29

01

03

64

01

09

30

1-00

01

63

1-99

07

May 1

0-99

2-00

62

98

0-3

2

98

1-98

61

97

04

3

97

97

60

95

03

4

96

96

59

94'

02

5

95

95

58

93

00

6

93

93

57

92

1-99

7

92

92

55

91

97

8

91

91

54

90

96

9

90

90

53

88

94

10

89

88

52

87

93

11

88

87

51

86

92

12

87

86

50

85

91

13

86

85

49

84

90

14

85

84

48

83

89

15

84

83

47

82

88

16

84

82

47

81

86

17

83

81

46

80

85

18

82

79

45

79

84

19

81

78

44

78

83

20

80

77

43

77

82

21

80

76

42

76

81

22

79

76

42

75

80

23

79

75

41

75

79

24

79

75

41

74

78

25

78

74

40

73

77

26

78

74

40

72

76

2"

77

73

39

71

75

28

77

73

38

71

73

29

76

72

38

70

72

30

76

71

37

69

70

31

76

71

37

69 1

70

Kegulus

(5 Leonis

S Virginis

SpicaVirg.

ll . Ill . s.

h. in s.

h. in. s.

ll. 11). s.

9 58 5957

11 40 4-73

114131-86

13 15 56 07

+ 2-83"

+ 306"

+ 3-00"

+ 3-04"

82

06

00

05

81

06

01

06

80

05

01

06

79

05

01

07

78

05

02

08

78

05

02

09

76

04

03

10

76

04

03

11

75

04

04

12

74

04

03

13

73

03

02

13

72

03

02

14

71

03

01

14

70

02

00

15

68

02

2-99

15

67

02

99

16

66

01

98

17

65

01

97

17

64

00

96

18

63

2-99

96

18

62

99

95

18

61

98

95

18

59

98

95

19

58

97

94

19

57

97

94

19

56

96

93

19

55

96

93

19

53

95

92

i, 20

52

94

92

20

51

93

91

20

50

92

90

20

49

92

90

20

47

91

89

20

46

90

88

20

45

89

87

20

44

88

87

20

43

87

86

20

41

87

85

20

40

86

84

20

39

85

83

20

38

84

82

20

36

83

82

20

35

82

81

20

34

81

80

20

33

81

79

19

32

80

78

19

31

79

78

19

29

78

77

19

28

77

76

19

27

76

75

19

26

75

74

18

25

74

73

18

24

73

72

17

23

72

71

17

21

71

71

16

20

71

70

16

19

70

69

15

18

69

68

14

17

68

67

14

16

67

66

13

1824.]

Thirty-Seven Principal Stars.

249

Arcturas

l a Librae

» Cor. Dor. 1

a Serpent

Antares i

>Herculis

lOpliiiichi

a Lyrae

y Aquilae

Heap AR 1

h. 111. s.

h. m. s.

l. m. s.

1. ID. s.

I. 111. s. 1

l. m. s.

1. in. s.

h. m. g.

ll. in. 8.

l»-'4. J

14 7 38-$*

14 41 963

15 -V 1445

5 35 3647

!6 1*37-91'

17 6 37-72'

17 L'S 46-34
+ 2-09"

IS 30 5899

1937 53-68

April 1

+ 2-91"

+ 3-03"

+ 2-60"

+ 2-66"

+ 2-96"

+ 2-17"

+ 1-30"

+ 1-41"

2

93

05

62

68

3-00

20

12

33

44

3

94

06

64

70

03

22

14

37

47

4

95

OS

66

72

07

25

17

40

50

5

96

10

68

74

11

27

20

43

53

6

97

11

70

76

15

30

23

47

55

7

99

13

73

79

19

32

25

50

58

8

3-00

15

75

81

22

35

28

53

61

9

02

16

77

83

26

38

30

57

64

10

03

18

79

85

30

40

33

60

6T

11

04

19

81

87

33

42

35

63

70

12

05

21

82

88

35

45

38

66

73

13

06

22

84

90

38

47

40

69

75

14

07

23

86

91

40

50

43

72

78

15

OS

25

87

93

43

52

45

75

81

16

08

26

89

95

45

55

48

78

84

17

09

27

90

96

48

57

50

81

87

18

10

29

92

98

51

60

53

85

89

19

11

30

94

3-00

54

62

55

88

92

20

12

32

96

02

56

65

58

92

95

21

13

33

97

04

5S

67

60

95

98

22

13

34

99

05

60

69

62

98

2-01

23

14

36

300

07

63

72

64

2-01

04

24

14

37

02

08

65

74

66

04

07

25

15

38

03

10

67

76

69

07

10

26

16

39

04

11

69

78

71

10

13

27

16

40

06

13

71

81

73

13

16

28

17

42

07

14

74

83

75

16

19

29

17

43

09

16

76

85

77

19

22

30

18

44

10

18

78

87

79

22

25

May 1

18

45

11

19

80

89

81

25

28

2

19

46

12

20

82

91

84

28

31

3

19

46

13

22

84

93

86

31

34

4

19

47

14

23

86

95

88

34

37

5

20

48

15

24

88

97

91

37

40

6

20

49

16

25

90

99

93

40

42

7

20

49

18

26

92

3-01

96

43

45

8

20

50

19

27

94

03

98

46

48

9

21

51

20

29

96

05

3-01

49

51

10

21

52

21

30

98

07

03

52

54

11

21

53

22

31

4-00

09

05

54

57

12

21

53

23

32

01

10

07

67

59

13

21

54

23

33

03

12

09

59

62

14

21

55

24

34

04

14

11

62

65

15

21

55

25

35

06

15

13

64

68

16

22

56

26

36

08

17

14

67

70

17

22

57

27

37

09

19

16

69

73

18

22

57

27

38

11

21

18

72

76

19

22

58

28

39

12

22

20

74

79

20

22

59

29

40

14

24

22

77

81

21

22

59

29

41

15

25

24

79,

84

22

22

59

30

41

17

27

25

81

86

23

21

59

30

42

18

28

27

84

89

24

21

60

30

43

19

30

29

86

91

25

21

60

31

43

20

31

31

88

94

2(

19

60

31

44

22

33

32

90

96

27

19

60

32

41

23

34

34

92

99

SS

19

61

32

45

24

36

36

94

3-02

SI

19

61

32

46

26

S7

38

97

04

81

19

61

3'1

47

27

30

39

99

OT

31

19

61

33

47

28

40

40

801

09

250

Corrections in Right Ascension of

[Apiul,

% Aquilse

8 Aquilae

12 a Capric.i a Cygni

|a Aquarii

JFonialliaut

a Pegasi

a And io in.

Mean AR 1

h. m. s.

h. m. s.

h. in. s. |h m. s.

Ih. m. e.

lb. in. 9.

h. m. s.

11. III. s.

1824. j

l'J-L'11-88

1946 40-23

20 8 17-02

2033 26-21

2156 44 6

'22 4" 543-1

22 56 0-i;

23 5918-67

April 1

+ 1-42"

+ 1-42"

+ 1-56"

+ 0-32"

+ 0-92'

1 + -si"

+ 0-59'

' + 0-36"

2

45

45

59

35

95

83

62

37

3

48

48

62

39

97

86

65

39

4

51

51

65

42

99

88

68

40

S

53

53

68

46

1-0 1

91

71

41

6

56

56

70

49

01

93

74

43

7

59

r>9

73

52

06

95

77

44

8

62

62

76

56

OS

97

79

45

9

64

65

79

60

11

1-00

82

47

10

67

68

82

63

13

02

75

48

11

70

71

85

67

15

04

77

50

12

73

74

88

70

18

07

79

52

13

76

76

91

74

20

09

82

53

14

79

79

94

77

23

12

84

55

15

82

82

97

81

25

14

S6

56

16

84

85

2-01

84

28

16

88

58

17

87

88

04

88

30

19

90

60

18

90

91

07

92

33

21

92

62

19

93

93

10

95

35

24

95

64

20

96

96

13

99

38

26

97

66

21

99

99

16

1-03

41

89

99

68

22

202

2-02

19

06

43

32

1-02

70

23

05

05

22

10

46

35

04

72

24

08

08

25

14

49

38

07

74

25

11

11

28

17

51

41

09

77

20

14

14

31

21

54

43

12

79

27

17

17

34

25

57

46

14

81

28

20

20

37

28

60

49

17

83

29

23

23

40

32

62

52

19

85

30

26

26

43

36

65

55

22

87

May '

29

29

46

40

68

58

25

90

2

32

32

50

43

71

61

28

92

3

35

35

53

47

74

64

30

95

4

38

38

56

51

77

67

33

97

5

41

41

59

55

80

70

36

1-00

6

43

43

63

58

83

73

39

02

7

46

46

66

62

86

76

42

05

8

49

49

69

66

89

79

44

07

9

52

52

73

69

92

82

47

10

10

55

55

76

73

95

85

50

13

11

58

58

79

77

98

88

53

16

12

61

61

82

80

2-01

92

56

19

13

63

63

85

84

04

95

59

22

14

66

66

88

87

07

98

62

25

15

69

69

91

91

10

2-01

65

27

16

72

72

93

94

13

04

68

30

17

75

75

96

98

16

08

71

33

18

77

77

99

2-01

19

11

74

36

19

80

80

3-02

05

22

15

77

39

20

83

83

05

09

25

18

80

42

21

S6

86

08

12

28

21

83

45

22

88

88

11

16

31

25

86

48

23

91

91

14

19

34

28

89

51

24

93

94

17

23

37

32

92

54

25

96

97

20

26

40

35

95

58

26

98

99

22

30

43

38

98

61

27

3-01

3-02

25

33

46

42

2-01

64

28

04

05

28

37

49

45

04

67

29

06

08

31

40

52

49

07

70

30

09

10

34

44

55

52

10

73

31

11

12

37

■ 47

58 1

55

13

76

1824.]

Thirty-Seven Principal Stars.

251

y Pegasi

Polaris

a Arielis 1

aCeti

Aldebaran

Capella

Rigel

$ Tauri

* Orionis

Mran AR1

h. m. s.

h. m. s.

h. m. g.

i. m. s.

ii. in. s. 1

h. m. s.

h. in. s.

1). m. s.

ll. ID. S.

1824. j

4 11-17

58 2 66

1 57 16-42

1 53 5-44

4 25 50-01 1

5 3 43-21

5 6 5-11

6 15 1052

•> 45 38-91

June 1

+ 1-85"

-19-23"

+ 1-42"

+ 1»18"

+ 1-18 '

+ 1-41"

+ 0-82"

+ 1-33"

+ 1-14"

2

88

1857

45

20

19

43

83

34

14

3

91

17-90

48

22

21

44

84

35

15

4

94

17-24

50

24

22

45

85

36

15

5

97

16-52

53

26

24

47

86

37

16

6

2-00

15-80

55

28

25

48

87

39

16

7

03

15-09

58

30

27

49

88

40

17

8

06

14-37

61

33

28

51

89

41

17

9

09

13-65

64

35

30

52

90

42

18

10

12

1292

f>7

37

32

54

91

43

19

1]

16

1219

70

40

34

56

93

45

20

12

19

11-46

73

42

35

58

94

46

21

13

22

10-73

76

45

37

60

95

48

22

14

25

1000

79

48

39

62

96

49

23

15

29

9-24

82

50

40

63

98

51

24

16

32

8-48

85

52

42

65

99

52

26

17

35

7-72

88

55

44

67

1-00

54

27

18

39

6-96

91

57

46

69

01

55

28

19

42

6-20

94

60

48

71

03

57

29

20

45

5-41

97

63

50

73

05

59

30

21

48

4-62

2 00

65

53

76

06

61

32

22

51

3-83

03

68

55

78

08

63

33

23

54

3-04

07

70

57

81

10

65

35

24

57

2-25

10

73

59

83

11

67

36

25

60

1-47

13

75

62

86

13

69

38

26

63

0-68

16

78

64

88

15

71

39

27

67

+ Oil

19

81

66

90

16

73

41

28

70

0-89

23

84

69

92

18

75

42

29

73

1-68

26

86

71

95

20

77

44

30

76

2-48

29

89

73

98

22

79

46

Sirius Castor i Procyon Pollux

MfanAR) h. m. s. h. m. s. h.
1824. j 6 37 23-49 7 23 21-46 7

in. s. h. m.
30 5-32 7 34 32-18

June 1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

0-76"
76
76
76
76
76
76
70
76
76
77
77
78
78
78
79
79
80
80
81
81
82
83
84
84
85
86
86
87
88

1-71 "
71
71
70
70
70
70
69
69
69
69
69
70
70
70
70
71
71
71
71
72
72
73
73
74
74
75
76
76
77

1-36"
36
36
35
35
35
35
34
34
34
54
34
34
34
35
35
35
35
83
35
36
36
37
37
38
38
39
39
40
41

a Hydra; j Regulus I /5 Leonis J0 Virginis i.SpicaVirg.

h. m. s. Ii. m. s. Ii. ni. s. h. m. s. h, m. s.
9 18 56-44 9 58 5957 II 40 473 11 41 31 -86 13 15 5607

•68"
68
68
67
67
67
67
66
66
66
66
66
66
66
66
67
67
67
67
67
68
68
69
69
70
70
71
71
72
73

•69"
68
67
66
65
64
63
63
62
61
61
60
60
59
58
57
57
56
56
56
55
55
54
54
53
53
52
52
51
51

2-15'
14
13
12
11
10
09
08
07
06
06
05
04
03
03
02
01
00
00

1-99
99
98
98
97
97
96
95
94
94
94

2-66'
65
64
63
62
61
60
59
58
57
56
55
54
53
52
50
49
48
47
46
15
44
43
42
41
40
39
38
37
36

+ 2

65"

64

63

62

62

61

60

59

58

57

56

55

54

53

52

51

50

49

48

47

46

45

44

43

43

42

41

40

39

38

313"
12
12
II
11
10
09
09
08
07
07
06
05
04
04
03
02
02
01
00
00

2-99
98
97
9G
95
95
94
93
92

252

Corrections in Right Ascension.

[April,

Arcturus

2 a Librae

aCor.Bor.

a Serpent. Antares

aHerculis

aOpbiuchi

a Lyras

y Aquilse

Mean AR 1

ll. 111. s.

ll. 111. s.

h. m. s.

h. m. s. li. in. f.

h in. s.

h. in. P.

li. in. s.

ll. in. S.

1824. i

14 7 38-33

14 41 963

15 27 14-4!

1535 3647 161837-91 17 6 3772

1726 46-24
+ 3-42"

18 30 58-90

19375368

June 1

+ 3-18"

+ 3-61"

+ 3-33"

+ 3-48"

+ 4-29"

+ 341"

+ 3-03 "

+ 3-12"

2

IS

61

33

4S

30

42

43

05

14

3

17

61

33

49

31

43

44

07

17

4

17

61

33

49

32

44

46

09

19

5

17

61

33

49

33

45

47

10

22

6

16

62

33

49

34

47

48

12

24

7

16

62

34

50

35

48

49

14

27

8

15

62

34

50

30

49

51

16

29

9

19

62

34

51

37

50

52

18

32

10

14

62

34

51

37

51

53

19

34

11

14

61

33

51

38

52

54

21

36

12

13

61

33

51

38

52

55

22

38

13

12

61

33

51

39

53

56

24

40

14

11

61

33

51

39

54

57

25

43

15

11

60

32

51

40

55

58

26

45

16

10

60

32

52

40

56

59

28

47

17

09

60

32

52

41

57

60

29

49

18

09

59

31

52

41

57

61

31

51

19

08

59

31

52

42

58

62

32

53

20

07

59

30

52

42

58

63

33

55

21

06

58

30

51

43

59

63

34

57

22

06

58

29

51

43

59

64

35

58

23

05

57

29

51

43

59

64

36

60

24

04

57

28

51

43

60

65

37

62

25

03

56

28

50

43

60

65

37

64

26

02

56

27

50

44

61

66

38

66

27

01

55

27

49

44

61

66

39

68

28

00

55

26

49

44

62

67

40

69

29

2-99

54

25

49

45

62

68

41

71

30

98

53 |

24

49

45

62

68

42

72

a Aquils

Aquilse 2«Capricor a Cygni a Aqnnrii

Fomalliaut

a Pegasi

lAndrom.

MeanAR\

li. m. s.

h. m. s. h. in. s. h. in. s. li. m. s.

h. m. s.

li. m. e.

ll. ill. s.

1824. )

19 4211-88

19 46 40-23 20 8 17-02

208526-21 215644-67

22 47 54-34

22 56 01 7

2359 18 67

June 1

+ 3-14"

+ 3-15"

+ 3-39"

+ 2-50" + 2-61"

+ 2-59"

+ 2-16"

■f 1-80"

a

16

17

42

53

64

62

19

83

3

19

20

45

56

67

66

22

86

4

21

22

48

59

71

69

25

89

5

24

25

51

62

74

73

28

93

6

26

27

53

66

77

76

32

96

7

29

30

56

69

80

80

35

99

8

31

32

59

72

84

83

38

2-03

9

34

35

62

75

87

87

41

06

10

36

37

64

78

90

90

44

09

11

38

39

67

81

93

94

48

13

12

40

41

69

84

96

97

51

16

13

43

44

72

87

99

3-01

54

20

14

45

46

74

90

3-02

04

57

23

15

47

48

77

93

04

07

61

27

16

49

50

79

95

07

11

64

30

17

52

53

82

98

10

14

67

34

18

54

55 84

301

13

18

71

37

19

56

57

87

04

16

21

74

41

20

58

59

89

06

19

24

77

44

21

60

61

91

09

22

28

80

48

22

61

62

93

11 24

31

83

51

23

63

64

96

14

27

35

86

54

24

65

66

98

16

30

38

89

58

25

67

68

4-00

18

33

41

92

61

26

69

70

02

21

36

45

95

64

87

70

71

04

23

38

48

98

68

28

72

73

07

26

41

52

3-01

71

29

74

75

09

28

44

55

04 !

74

30

75 |

77

11

30

47

58

07 1

77

1824.] M. Aifwedson on Uranium* 253

Article IV.

A Contribution to a more accurate Knowledge of Uranium*
By J. A. Arfwedson.

Uranium in the state of an oxide is occasionally found native
pretty pure, as, for example, in uran ochre and uran mica; but
the scarcity of these minerals has prevented them from being
employed for preparing oxide of uranium in any considerable
quantity. Chemists have, therefore, in their researches on this
metal, been obliged to employ the more abundant mineral called
pechblende, in which oxide of uranium is likewise found, mixed
with several other bodies from which it is with difficulty sepa-
rated.

Klaproth found pechblende, from Joachimsthal, in Bohemia,
to contain, together with protoxide of uranium, silica, oxide of
iron, and sulphuret of lead. He extracted the protoxide of ura-
nium in the following way : The pulverised mineral was dissolved
in nitric acid, the silica and sulphur remaining undissolved.
From the filtered solution was separated by crystallization in the
first place, the lead, under the form of nitrate of lead. The liquid
being further evaporated, the nitrate of uranium crystallized,
which was finally decomposed by caustic potash. The oxide of
iron remained in the mother ley.

Bucholz prepared his oxide of uranium in this manner. — The
pulverised pechblende was boiled with nitric acid, as long as
any thing was dissolved. The solution was evaporated at a high
temperature till fumes of nitrous acid were extricated, and this
was continued for a considerable time, taking care to stir the
matter continually. The salt of uranium was then taken up by
water, while the oxide of iron remained behind undissolved.
Bucholz found, however, that the solution contained likewise
copper and lime ; which were separated in this manner. The
liquid was decomposed by caustic ammonia added in excess, and
digested for some time along with the precipitate. By this pro-
cess the precipitate was freed from copper. It was washed and
heated to redness to drive off the whole of the ammonia. It was
again dissolved in nitric acid, and precipitated by caustic potash,
added as little as possible in excess. The oxide of uranium thus
obtained retained its yellow colour after being heated to redness,
and was considered as free both from lime and potash.

From the knowledge of the subject which we at present .pos-
sess, it is easy to see that neither Klaproth nor Bucholz could
have obtained a perfectly pure oxide of uranium, on account of
the great variety of substances accidentally present in pech-
blende, the names of which I shall state below.

• Tranblated from the Kongl. Vetenskaps Academiens Ilandlingar, for 1822, p. 404.

254 M. Arfwedson on Uranium. [April,

Method of preparing pure Oxide of Uranium.

I expected at first to have been able to obtain pure oxide of
uranium without any tedious processes, by means of one of its
properties which has not been known for any considerable time ;
namely, that it dissolves with facility in carbonate of ammonia,
and is again precipitated from the solution by boiling; for
should some copper accompany it in the solution, the oxide of
uranium which first is precipitated ought to be quite free from all
admixture of that metal.

A portion of pechblende from Johann Georgenstadt in Saxony,
which was apparently very pure, was reduced to a fine powder,
and digested with nitric acid till it was completely decomposed.
After this a little muriatic acid was added, which dissolved a
considerable portion of the straw-yellow matter, insoluble in
nitric acid. The filtered solution was supersaturated with car-
bonate of ammonia in great excess. A portion of the precipitate
was again dissolved by the carbonate, but the greatest part
remained undissolved ; and this proportion continued unaltered
though the whole was heated. The ammoniacal solution was
separated from the precipitate, and was examined by means of
processes which I consider it unnecessary to particularize in this
place, and to my astonishment 1 found it to contain the following
different substances; namely, oxide of uranium, oxide of copper,
a considerable proportion of oxide of cobalt, a little oxide of
zinc ; and the precipitate, besides all these bodies, contained
much arsenic mixed with oxides of iron and lead. If to these
we add the silica and sulphur not dissolved by the acids, we
shall find that the pechblende contains no fewer than nine differ-
ent substances. To free oxide of uranium from so many other
bodies occasioned a great number of fruitless trials. But I at
last succeeded in discovering the following method, by means
of which, so far as I can see, the protoxide of uranium may be
obtained in a state of complete purity.

Finely pulverized pechblende is dissolved by means of a gentle
heat in a mixture of nitric and muriatic acids. When the
decomposition of the mineral is completed, and most of the acid
expelled, a little muriatic acid is to be added, after which the
liquid is to be diluted with a good deal of water. The sulphur,
silica, and a portion of the gangue, remain finally undissolved.
A current of sulphuretted hydrogen gas must now be passed
through the liquid as long as any precipitate continues to fall.
The precipitate is at first dark-brown, consisting of sulphurets of
copper, arsenic, and lead ; but at last it becomes yellow, and
consists of sulphuret of arsenic. The liquid is now free from
copper, lead, and arsenic, but it contains iron, cobalt, and a
little zinc.

Let it be filtered and digested with a little additional nitric
acid to peroxidize the iron. By this process the light green

1824.] M. Arfwedson on Uranium. 255

colour of the liquid changes to a yellow. It must now be decom-
posed by means of carbonate of ammonia added in excess, which
will take up the oxide of uranium mixed with oxides of cobalt
and zinc ; but leaves a great quantity of oxide of iron undis-
solved. Should the solution even contain a portion of earth,
which did not happen in my experiments, almost the whole of it
would be separated mixed with the oxide of iron. The filtered
solution is afterwards made to boil, and the boiling is continued
as long as the carbonate of ammonia is disengaged. A portion
of the oxide of cobalt remains in the solution, which acquires a
faint reddish colour ; but another portion of it is precipitated
along with the oxide of uranium ; which contains likewise the
zinc. The precipitate is collected on the filter, washed, and
dried. It is then to be heated to redness ; by which it loses its
yellow colour, and becomes dark-green. In this state it must
be macerated for some time in dilute muriatic acid, which dis-
solves the oxides of cobalt and zinc, together with a small por-
tion of peroxide of uranium. This portion was probably united
as an acid with the two bases. Pure protoxide of uranium
remains undissolved. If the muriatic solution be precipitated
with caustic ammonia in excess, we obtain oxide of uranium
combined with oxides of cobalt and zinc. From 38-i- parts of
pechblende treated in this way, I obtained about 25 parts of
protoxide of uranium. This amounts nearly to 65 per cent,
which is 15 parts less than the quantity stated by Klaproth.

Metallic Uranium and Protoxide of Uranium.

The experiments hitherto made to obtain uranium in the
metallic form have been all conducted in charcoal crucibles with
or without additions. It is consequently probable, even if the
oxide of uranium operated upon had been quite pure, that the
metal obtained contained charcoal, or some other substance
derived from the fluxes employed in the reduction. In which
case the properties of the product might differ materially from
those of the pure metal. Fortunately chemists have found out
a method of avoiding these inconveniences in the reduction of
metals ; for it is now known that several metallic oxides may be
deprived of their oxygen by means of hydrogen gas. I deter-
mined, therefore, to try whether oxide of uranium could not be
brought to the metallic state by this method. If I succeeded I
obtained naturally the proportion of oxygen in the oxide deter-
mined with the requisite exactness.

The apparatus employed in this process was a piece of a com-
mon barometer tube, blown into a small globe about the middle
part. This tube was in the first place weighed, and then a
portion of finely pulverized protoxide of uranium which had been
heated to redness was introduced into the globular part of the
tube. Before determining the weight of this powder, the glass

256 M. Atfwedsoti On Uranium. [April,

was heated by a spirit lamp, in order to drive off any moisture
that might have been adhering to the powder, and this moisture
was sucked out of the tube by the mouth. The tube was then
placed in continuity with an apparatus from which hydrogen gas
was extricated from a mixture of zinc and dilute sulphuric acid.
This gas was made to pass in the first place through a tube filled
with fused muriate of lime in order to dry it. It then entered
into the tube containing the protoxide of uranium ; and as soon
as it had expelled the atmospheric air, heat was applied to the
protoxide by means of an Argand's spirit lamp. The reduction
took place immediately, and with such violence that the matter
became red-hot. Water was generated, and at the end of the
process, which only lasted a few minutes, the green protoxide
was changed into a powder of a liver-brown colour. 1*1 87 parts
of protoxide of uranium had lost by this process 0*042 part,
which amounts to 3*53 per cent. In another experiment 1*468
lost 0*052, which amounts to 3*54 per cent. The experiment
was repeated once more in a porcelain tube which was heated to
whiteness ; but the product was the same brown powder.

This substance remains unaltered at the ordinary temperature
of the atmosphere ; but when heated to the commencement of
redness, it takes fire, swells, and is converted into green oxide.
It is insoluble in sulphuric and muriatic acids, whether concen-
trated or diluted ; but it dissolves with facility in nitric acid with
the evolution of nitrous gas, and the solution has a lemon-yellow
colour. It is exceedingly probable that the protoxide of ura-
nium is by this treatment reduced to the metallic state ; but it is
certainly possible that I only reduced it to a lower state of oxi-
dizement.

Meanwhile I undertook some experiments in order to deter-
mine the composition of the yellow oxide of uranium, by means
of which I expected to be able to throw some light on the ques-
tion, whether the substance obtained in the preceding experi-
ments should be considered as a metal or not. If I could
prepare a neutral salt with peroxide of uranium and sulphuric or
muriatic acid, I should have an easy way of determining the
quantity of oxygen in the oxide by the analysis of the salt ; but
neither'of these salts could be obtained in the state of crystals ;
for on evaporating the solutions, I obtained at last a thick syrup,
which, when further evaporated, became greenish-yellow from
the formation of protoxide of uranium. On the other hand,
when I added to the permuriate of uranium a portion of muriate
of potash, a triple salt separated on evaporating the liquid in
small lemon-yellow crystals. Since hydrogen gas reduces the
protoxide of uranium with such facility, I thought it likely that
this triple salt might also be decomposed by means of it, and
that its analysis could be best performed in the way that Berze-
lius proceeded with the analysis of potash-muriate of platinum ;

1824.] M. Arfwedson on Uranium. 257

for potash-muriate of uranium may be freed from water without
the least difficulty, as the salt can be exposed to a moderate red
heat without undergoing any decomposition.

The experiment was conducted in the first place in an appa-
ratus similar to that above described. As soon as the hydrogen
gas began to pass, and the salt became hot, it fused and swelled
up, muriatic acid gas was given out, and the mass became dark-
coloured and opaque. Though the process was continued for
nearly two hours, and the heat from the Argand's spirit lamp
was raised to the highest degree of intensity, vapours of muriatic
acid still continued to pass ; a proof that the salt was not com-
pletely decomposed. The whole being allowed to cool, the
matter was extracted by water, which dissolved muriate of
potash, together with a good portion of uranium salt, of a light-
green colour. The insoluble residue was a black crystallized
powder having the metallic lustre, which was washed, and dried
upon blotting paper.

Supposing that the heat in this experiment might have been
too weak, and that the salt, if exposed to a higher temperature,
might have been more completely decomposed, it was again
repeated with this difference, that the salt was put into an appa-
ratus, which could be more strongly heated, and which was
introduced half way into a small furnace heated with charcoal.
The heat applied was so strong that the glass was almost melted ;
yet the salt was not completely decomposed ; for after washing
the altered salt with water, there remained the same crystallized
matter as in the preceding experiment; but of a still more
decided metallic appearance ; for the salt had been employed in
greater quantity, and on that account the crystals were larger
and more distinct. The form of these crystals as seen under the
microscope was an octahedron very nearly regular, whose faces
had a very strong metallic lustre. Some of them were slightly
transparent at the edges, and of a reddish-brown colour; and
this colour remained even after the crystals Avere reduced to
powder. These crystals were not altered by exposure to the
atmosphere ; but when heated, they were reduced to powder,
increased in bulk, and were changed into green protoxide of
uranium, which, when treated with acids, exhibited the very
same characters as the products of the reduced protoxide.

It is scarcely possible to think, that in this experiment an
oxidized body could have been obtained ; especially if the double
salt employed be viewed according to the new theory of the
nature of muriatic acid, according to which that acid contains
no oxygen whatever. All the circumstances taken together
lead to the conclusion, that the crystallized body obtained was
metallic uranium. Ob'36 part of it were heated in a platinum
vessel, and converted into green oxide. The increase of weight
was U-U2:$5, or 100 parts of the metal had combined with 3-(j!J/i
parts of oxygen. For the sake of security the oxide was dissolved

New Series, VOL, VI I. s

258 M. Arfwedson on Uranium. [Apr it,

in nitric acid, the solution evaporated to dryness, and exposed
to a red heat ; but by this process no alteration whatever of the
weight was produced.

The experiment was repeated with 1 -006 gramme of metal,
which increased in weight 0-0375 gramme, corresponding to
3*73 oxygen to the 100 of metal.

These two experiments agreeing very well with each other
show plainly that the brown substance obtained when protoxide
of uranium was reduced by means of hydrogen gas, must like-
wise be in the metallic state. A hundred parts of the protoxide
lost 3*53 or 3-54 of their weight, leaving a remainder amounting
to 96-47 or 96-46. But 96-46 i 3-54 :: 100 : 3-67, which loss
quite corresponds with the augmentation of weight of the metal
when heated to redness. It was formerly remarked, that the
metal when obtained by reducing the protoxide by means of
hydrogen gas has a liver-brown colour; while on the other hand
the powder of the crystallized product is reddish-brown ; but
this may be owing to no other cause than a difference in the
fineness of the two powders.

If the result of the reduction of the protoxide be compared
with that which is obtained by the combustion of the metal, 100
parts of protoxide of uranium are composed at a medium of

Uranium 96-443

Oxygen 3-557

100-000

and 100 parts of uranium combine with 3*688 parts of oxygen.

The protoxide of uranium obtained from percarbonate is a
powder of a dirty-green colour. If the uranium salt be a second
time thrown down by caustic ammonia, and the precipitate be
heated to redness, the protoxide is obtained in the form of a
black metallic mass, the particles of which cohere together.
This mass is exceedingly hard, and is not without difficulty
reduced to powder. The powder has the usual green colour of
protoxide of uranium. Protoxide of uranium after having been
heated to redness, dissolves very sparingly in dilute muriatic or
sulphuric acid. The concentrated acids dissolve it better, and
when it is boiled in concentrated sulphuric acid, it dissolves
completely, a light-green coloured saline mass is obtained, which
dissolves in water with a deep bottle-green colour. If such a
solution be precipitated by caustic ammonia, the protoxide is
separated in the state of a hydrate, in brown flocks inclining to
purple. If these flocks be washed and dried at the temperature
of 212°, and then heated in a glass tube, they give out a consi-
derable portion of water, and become green. In general a por-
tion of the hydrate is likewise converted into peroxide, and it
becomes yellow before the end of the drying; and if it was
precipitated by ammonia in great excess, or if it was washed

1824.] M. Arfwedson on Uranium. 259

with hot water, in either case we may generally expect to
find the whole after being dried in the state of peroxide
containing ammonia. Carbonate of ammonia throws down a
light-green precipitate of protocarbonate of uranium, which is
again dissolved if the precipitant be added in excess. If the
precipitate be heated in ammonia, we obtain protoxide of ura-
nium free from carbonic acid. The hydrated protoxide dissolves
very easily in acids ; and the precipitate by means of caustic
ammonia is easily dissolved again if a little excess of acid be
added to the liquid ; but if the precipitated hydrate be digested
for an hour in water, the chemically combined water is disen-
gaged, the matter concretes into a heavy powder of small bulk,
and is afterwards acted upon with great difficulty by acids.

Yellow Oxide of Uranium.

Peroxide of uranium, as is well known, has the property of
acting sometimes the part of an acid, and at others that of an
alkali ; and it has such a tendency to enter into combination
with other oxidized bodies, that I doubt the possibility of obtain-
ing it in an insulated state. For example, if we precipitate a
solution of this oxide in muriatic or nitric acid by means of
caustic ammonia, the precipitate is a chemical combination of
peroxide of uranium with water and ammonia, which last body
cannot be removed by washing the powder. The very same
result is obtained, if we precipitate the peroxide by means of
caustic potash. The hydrated uraniate of ammonia may be
heated without undergoing decomposition to 212°, or a little
higher. When raised to a still higher temperature, it gives out
water, azotic gas, and ammonia, and protoxide of uranium
remains behind. If we attempt on the other hand to heat per-
nitrate of uranium in order to disengage the acid, the decomposi-
tion of the salt does not cease till the whole mass is converted
into protoxide ; and this result takes place in what way soever
we regulate the temperature.

Considering the small quantity of oxygen in the protoxide
of uranium, it was of the utmost importance in determining the
quantity of oxygen in the peroxide to employ a method which
was not liable to any uncertainty. It occurred to me that I
should obtain such a method if I combined peroxide of uranium
with a basis, the proportion of whose oxygen was accurately
known ; and then, by means of hydrogen gas, deprived both
substances of their oxygen. Knowing the proportions of per-
oxide of uranium and basis, and the proportion of oxygen on the
base, we should have the oxygen in the peroxide. To enable
me to employ such a method, some preliminary experiments
were undertaken, by which I found that when to a solution of
peroxide of uranium in muriatic acid any earthy or metallic
muriate is added, and then caustic ammonia is added to the
mixture, in all such cases the peroxide of uranium is precipitated

260 M. Arfwedson on Uranium. [Aprij.,

in combination with the earth or metallic oxide in the form of a
uraniate, even when the base consists of a substance which,
when in an insulated state, is not precipitated by ammonia ; for
example, when it is lime or barytes ; and in this way a whole
series of uraniates may be obtained, which, however, do not
resemble other salts in their composition, as will be seen more
particularly hereafter. When peroxide of uranium is united to a
basis capable of withstanding the fire, it can resist a high tempera-
ture without losing any of its oxygen. When, on the contrary,
1 examined a uraniate having an easily reducible basis, the com-
position of which was known before, I in that case first reduced
the salt by means of hydrogen gas, which gave me the quantity
of oxygen contained in both oxides ; then determining the quan-
tity of oxygen in the basis I had that in the peroxide of uranium,
I employed for this purpose uraniate of lead as most suitable to
this kind of investigation.

Analysis of Uraniate of Lead.

The salt was prepared in this manner. Solutions of pernitrate
of uranium and nitrate of lead were mixed together, and precipi-
tated by caustic ammonia. The precipitate thus obtained was
washed, and exposed to a red heat. It probably contained an
excess of oxide of lead, in the form of subnitrate, as the nitrate
of lead had been added in considerable excess ; but this was of
no consequence. The precipitated compound after being heated
to redness and pulverized, had a cinnamon-brown colour, and it
gave a full lemon-yellow solution in muriatic acid ; showing that
the peroxide of uranium had lost none of its oxygen.

1*969 gramme of uraniate of lead was reduced by means of
hydrogen gas in the same way as the analysis of the protoxide of
uranium was performed. As soon as it began to be red hot, it
gave out much water, and when this ceased the process was
stopped. The product consisted of a dark-brown powder,
which weighed 0*127 less than the uraniate of lead. But this
difference in weight could not be determined with accuracy,
because the apparatus while weighing was constantly increasing
in weight. The reduced mass became at the same time hot, and
when thrown upon paper, it took fire, and became quite ignited,
leaving uraniate of lead as a residue.

This singular phenomenon, owing pVobably to the rapidity
with which the alloy of uranium and lead absorbed oxygen, was
so much the more unlooked for, as these metals, when in a
separate state, do not undergo any change in the common tem-
perature of the atmosphere. There miglit, in this case, have
been produced an electro-chemical process between them, which
occasioned their combustion. Meanwhile no accurate conclu-
sion could be drawn respecting the oxygen which the two metals
contained. The experiment, therefore, was repeated, with this
alteration, that the water was collected in a receiver, filled with

1824.] M. Arfwedson on Uranium. 261

fused muriate of lime, previously exactly balanced to determine
its weight.

From 2*3 grammes of uraniate of lead, previously heated to
redness, were obtained in this way 0*164gr. of water, equivalent
to 0-1459 oxygen.*

0628 gramme of uraniate of lead, prepared at the same time,
were dissolved in nitric acid. The solution was mixed with
sulphuric acid in sufficient quantity to saturate the oxide of
lead, and then evaporated almost to dryness. I found it neces-
sary to dissolve the uraniate of lead in the first place in nitric
acid ; for if it be decomposed directly by sulphuric acid, it is not
possible to obtain the sulphate of lead white, and quite free from
oxide of uranium. The mass was finally digested in alcohol,
which dissolved the sulphate of uranium, and left the sulphate
of lead. This last salt was collected on a filter, and washed
with alcohol. After being heated to redness, it weighed 0*485
gr. which corresponds with 0*357 protoxide of lead. The
remainder of the 0-628 amounting to 0*271 was of course per-
oxide of uranium. Thus it appears that 2*3 uraniate of lead
consist of 1*307 protoxide of lead, and 0*993 of peroxide of
uranium. The oxygen in the former of these constituents is
0*0937 ; but the oxides of lead and uranium had together lost
0*1459 of oxygen; and consequently 0*0522 of oxygen must
have belonged to the peroxide of uranium. It follows ultimately
that 100 parts of peroxide of uranium contain 5*252 of oxygen.

The experiment was repeated with a uraniate of lead of
another preparation ; because all the first stock was exhausted.

1*26 gr. reduced by means of hydrogen gas, gave 0*0785
water, corresponding with 0*0698 oxygen ; 1*258 gr. of the salt
was decomposed by sulphuric acid, and was found to be a com-
pound of 0*173 protoxide of lead, and 1*085 peroxide of uranium.
1*26 gr. of the uraniate of course consist of 0*1733 protoxide of
lead and 1*0867 peroxide of uranium ; which together contain
0*0698 oxygen ; but 0*1733 protoxide of lead contain 0*0124
oxygen. Thus it appears that the oxygen in 1*0867 peroxide of
uranium is 0*0574; and 100 parts of peroxide of uranium con-
tain 5*282 oxygen. The preceding experiment gave 5*252 ; the
mean of both is 5*267. From this it follows, that 100 parts of
uranium, in order to become peroxide, must combine with 5*559
oxygen.

But that the whole might not depend upon a single set of
experiments, I determined likewise to analyze

Uraniate of Eari/tes.

It was prepared in this manner. A mixture of the solutions
of permunate of uranium and muriate of barytes, both previously
boded, was precipitated by caustic ammonia. The precipitate

• The oxygen in the water was reckoned 88'9<t per cent, according to the experi-
ment* of Berzeliug and Dulong.

262 M. Arfwedton on Uranium. [April,

was collected on a filter, and hastily washed with fresh boiled
water, to prevent any mixture of carbonate of barytes. The
uraniate of barytes, after being dried and heated to redness, had
a fine yellow colour, which became lemon-yellow when the salt
Was reduced to powder.

1-343 gramme of uraniate of barytes previously heated to
redness, being dissolved in nitric acid, and decomposed by
means of sulphuric acid, gave 0-295 gr. of sulphate of barytes,
or 0-194 barytes. The solution which contained the peroxide of
uranium was evaporated to dryness, and the dry salt heated to
decomposition in a platinum crucible ; for this a strong and long
continued heat was required to drive ofT the last portion of the
sulphuric acid. The residue was protoxide of uranium, which
weighed 1-121. When dissolved in nitric acid, no turbidness
appeared indicating the presence of any sulphate of barytes :
1-343 uraniate of barytes had thus given 0-194 barytes, and
1-121 protoxide of uranium, making together T315. The loss,
amounting to 0-028, must of course be the difference between
the quantity of oxygen in the protoxide and peroxide of ura-
nium; but 1-121 : 0-028 :: 100 : 2*5 ; consequently 100 protoxide
of uranium, in order to become peroxide, must combine with 2-5
oxygen.

T456 gr. uraniate of barytes of another preparation gave
0-364 sulphate of barytes (equivalent to 0-239 barytes), and T186
protoxide of uranium. The oxygen driven off in this experi-
ment is 0-031 with 1-186 protoxide; this to 100 parts is equiva-
lent to 2-61. The mean of 2-50 and 2-61 is 2-55; and 100
parts of peroxide of uranium ought, according to these experi-
ments, to contain 5-96 oxvsen, and 100 of the metal combine
with 6-34 oxygen, in order to become peroxide.

Although the uraniate of barytes was formed in both cases
in the same way, so that the liquid from which it was prepared
contained always a quantity of uncombined ammonia; and
although a quantity of muriate of barytes in both cases remained
unprecipitated in the liquid, yet we perceive that the uraniate
of barytes first prepared contained a considerably smaller pro-
portion of basis than the second. It is possible that the peroxide
of uranium, being a weak acid, may undergo some modification
in its capacity of saturation, according as the muriate of barytes
is present in a greater or smaller proportion relative to the
muriate of uranium.

Analysis of the Sulphate of Uranium and Potash.

This double salt being less soluble in water than the muriate
of uranium and potash, crystallizes more readily, and may, by
means of crystallization, be completely freed from any excess of
the salt of potash, I consider this salt on that account as more
suitable for analysis than the muriate.

Potash-sulphate of uranium is obtained by evaporating a

1824.] M. Arftcedson on Uranium. 263

solution of sulphate of uranium to which some sulphate of potash
has been added. It forms a confused crystallized mass of an
exceedingly beautiful lemon-yellow colour. When heated, it
gives out in the first place water, and when the heat is aug-
mented melts, and flows into a liquid. The fused salt is green-
ish-yellow, and therefore has probably undergone a partial
decomposition; although it gives a full lemon-yellow solution in
water ; but if the salt be heated only to a commencement of
fusion, it retains its yellow colour completely.

A solution containing 2T72 grs. of crystallized and anhydrous
potash-sulphate of uranium was precipitated by muriate of
barytes. The sulphate of barytes being separated, washed, and
heated to redness, weighed 1-814 gr. corresponding to 0*623
sulphuric acid.

The filtered liquid was saturated with caustic ammonia, which
precipitated uraniate of barytes. It was collected on the filter
and weighed. The residual liquid was mixed with a sufficient
quantity of sulphuric acid both to separate any barytes that
might remain, and in order finally to obtain a sulphate of potash
quite free from muriatic acid. After this the whole liquid was
evaporated to dryness ; the dry salt was heated to redness in a
weighed platinum crucible, by which the ammoniacal salts were
volatilized, and sulphate of potash remained, which was rendered
neutral by the fumes of carbonate of ammonia. It weighed
0*533 gr. equivalent to 0*288 gr. of potash. The salt dissolved
in water without residue, and the solution was neither rendered
turbid by ammonia, nor by nitrate of silver; showing that ft
contained neither oxide of uranium nor muriatic acid. The sul-
phuric acid and the potash were thus determined ; what is
wanting to make up the original quantity of salt employed must
be peroxide of uranium. It follows that the constituents of the
double salt must be :

Sulphuric acid 0-623

Potash 0*288

Peroxide of uranium 1*261

2*172
Or in 100 parts :

Sulphuric acid 28*68

Potash 13*26

Peroxide of uranium 58*06

100-00

13*26 potash are saturated by 11*26 sulphuric acid. There
remain 17*42 acid which belong to the 58*06 of peroxide of ura-
nium ; but 17*42 sulphuric acid saturate a quantity of basis
contaiaing 3477 oxygen; 100 parts of peroxide of uranium

264 M. Arfivedson on Uranium. [April,

consequently contain 5*99 oxygen ; or 100 parts of the metal, in
order to beperoxidized, combine with 6*37 oxygen.

The oxygen of the potash is to that of the peroxide of uranium
as 2 to 3 ; for the oxygen in 13*26 potash is 2*248, and in 58*06
of peroxide of uranium 3*477. Now 2*248 : 3*477 :: 100 :
154*7.

If we now collect the results of all these experiments to deter-
mine the quantity of the oxygen in the peroxide, we shall find
them as follows :

100 parts of uranium take up, according to the analysis of

Oxygen.

Uraniate of lead 5*559

Uraniate of barytes 6*340

Potash-sulphate of uranium 6*370

The number 5*559 has almost the same ratio to the oxygen in
the protoxide that 3 has to 2 ; for in the protoxide 100 parts of
uranium are combined with 3*688 parts of oxygen, which, mul-
tiplied by li, = 5*532 ; but the last two numbers lie between
1^ and twice 3*688. It is difficult to determine which of these
numbers come nearest the truth. The last two, although
obtained different ways, accord in a remarkable degree ; and
have in consequence some claim to be considered as accurate.
But on the other side it is clear that the experiments made with
uraniate of lead ought to come out with greater precision ;
because the analytical method followed with respect to it puts it
in our power to attain a higher degree of accuracy than is likely
in the two following experiments. I must in the mean time
acknowledge that these experiments do not furnish us with the
knowledge of the composition of the oxides of uranium with that
degree of accuracy which chemists have a right to require. At
the same time it may be admitted as most likely that the oxygen
in the peroxide of uranium is 1^ times as great as in the protox-
ide ; unless we were to admit that the second composition, such
as it was found, can be completely depended on ; and this there
is not much reason to do, as both the oxidizement of the metal
and the reduction of the protoxide, give the same composition of
the oxide.

According to M. Schonberg's experiments on the composition
of the oxides of uranium,* the oxygen in the protoxide is to that
in the peroxide as 2 to 3 • for he found the protoxide to contain
6, and the peroxide 8*73 per cent. The oxygen in the protoxide
was determined by analysing the protomuriate of uranium • and
the composition of the peroxide was determined by the loss of
weight which it sustained when heated to redness, by which it
was converted into protoxide. But it appears from my experi-
ments, that the protomuriate can never be obtained neutral and

* De conjunctione chemica ejusque ratiojiibus. Upsalke, 1813.

1824.]' M. Arfwedson on Uranium. 265

free from peroxide without undergoing decomposition. It is
probable, therefore, that M. Schonberg's experiments were made
upon a salt containing an excess of acid, in which case it is
obvious that he must have overrated the quantity of oxygen con-
tained in the basis. The peroxide employed in his second deter-
mination was obtained by decomposing pernitrate of uranium by
means of heat ; but this mode of experimenting cannot be deci-
sive, as from what has been stated it must be evidently impossible
to drive off the nitric acid completely from this salt without con
verting the basis partly into a protoxide.

100 parts of uranium to form the protoxide combine with
3*688 oxygen. If this represents two atoms of oxygen, as is
probable, then an atom of uranium will weigh 5422*99. Peroxide
of uranium precipitated by a caustic alkali is insoluble in an
excess of the precipitating substance, and always contains a
little alkali, which cannot be washed out, but is found, together
with an earthy or metallic salt in ihe water, as the peroxide of
uranium is precipitated in combination with an earth or metallic
oxide. In alkaline carbonates, and in particular with carbonate
of ammonia, peroxide of uranium is easily soluble. The solution
has, a strong lemon colour, and even an inconsiderable portion of
peroxide of uranium is capable of giving that colour to water.
By boiling, the peroxide of uranium precipitates in the state of a
pale-yellow powder, which contains carbonic acid, and even
some ammonia. We must not, however, reckon upon obtaining
the whole oxide ; because however pure it may be, there always
remains a little in the water ; and when the carbonated oxide is
put upon the filter and washed, the water employed in the edul-
coration, especially towards the end, contains a good portion of
oxide in solution, which again falls when the liquid comes to be
mixed with the saline solution. The peroxide precipitated by
caustic ammonia acts in precisely the same way. Peroxide of
uranium, therefore, may be considered as slightly soluble in
water. This solubility is partly, but not entirely prevented by
washing it with water containing sal ammoniac dissolved in it.
On the other hand, if peroxide of uranium be united to an earth
or a metallic oxide, it is not in the least soluble in water.

According to what has been already stated, peroxide of ura-
nium unites with the other earths and metallic oxides into a kind
of uraniates, in all cases, when the mixed solutions of both are
precipitated by caustic ammonia. These compounds may be
reduced by means of hydrogen gas to the state of alloys of
uranium, and the basis of the earth or oxide employed, even
when the earthy basis is barytes. These alloys again absorb
oxygen at the common temperature of the atmosphere, and the
oxidizement is accompanied by combustion. They constitute,
therefore, a peculiar kind of pyrophori not inferior to those
already known. The alloy of uranium and lead has been already
mentioned. An analogous body is obtained when uraniate of

266 M. Arfwedson on Uranium* [April,

barytes is reduced ; and the alloy of uranium andiron burns still
better than either of the others.

Uranium appears to have a very weak affinity for sulphur.
The sulphuret may be obtained by the moist way, as is already
known, if a solution of uranium be precipitated by an alkaline
hydrosulphuret ; but I have not been able to succeed in forming
sulphuret of uranium by the dry way. When dry sulphuretted
hydrogen gas is passed over red-hot protoxide of uranium, the
oxide is reduced immediately, water and sulphur exhale, and a
body remains in all respects similar to the metallic uranium,
and which contains only 1*61 per cent, of sulphur.

Salts of Uranium.

The protosalts of uranium in a state of purity are not easily
prepared. If we dissolve protoxide of uranium in concentrated
sulphuric or muriatic acid (which, in the second case, goes on
very slowly), the solution at first is dark bottle-green; but it
becomes gradually lighter, and at last assumes a greenish-yellow
colour from the formation of peroxide. The sulphuric acid solu-
tion when evaporated deposits a light green confusedly crystal-
lized mass which contains a mixture of protoxide and peroxide
of uranium. The muriatic acid solution may be evaporated to
dryness without the deposition of any crystals.

Persalts. — The persulphate of uranium is formed, when nitric
acid is added to a solution of protosulphate of uranium. This
addition, the green colour speedily passes to yellow, even with-
out the assistance of heat.

The salt does not crystallize even when evaporated to the con-
sistence of a syrup. If we continue the application of the heat
after the salt has become dry, the oxide loses a portion of its
oxygen, and the mass acquires a greenish-yellow colour.

Pernitrate of uranium is formed when the protoxide is dis-
solved in nitric acid. The solution goes on with rapidity, espe-
cially if assisted by heat. Nitrous gas is disengaged, and we
obtain a yellow liquid, which, when evaporated, shoots into long
prismatic crystals of a fine yellow colour. The salt dissolves
readily in water, and is decomposed in a comparatively low tem-
perature ; oxygen gas is also disengaged, and pernitrate of
uranium formed. When heated just to redness, it is decomposed
completely ; nitrous acid is driven off, and protoxide of uranium
remains.

Permuriate of 'uranium is formed in the same way as the per-
sulphate. It does not crystallize, though evaporated to the
consistence of a syrup. The dry salt is very deliquescent.

Percarbonate of uranium has been already described.

Double Salts.

Peroxide of uranium seems to have a great disposition to form
double salts in combination with other bases. It has been

1824.] On the Oxidum Manganoso-Manganicum. 267

already stated that a solution of persulphate or perrauriate of
uranium does not crystallize ; but if a portion of sulphate or
muriate of potash be added to the solution, we obtain by evapo-
ration a uranium salt in combination with the alkaline salt.

Potash-persulphate of uranium forms a granular crystallized
mass, of a very fine lemon-yellow colour. The salt dissolves
pretty easily in water. By alcohol it is decomposed in such a
way that the persulphate of uranium is dissolved, and the alkaline
salt remains behind undissolved. When heated, it loses its
water, melts at a low red heat, and begins in this temperature to
undergo decomposition ; for it acquires a green colour ; but the
decomposition is very inconsiderable, for even after being com-
pletely fused, it dissolves again in water with a lemon-yeliow
colour. Before it begins to melt it is not altered in the least.
The constituents of this salt in an anhydrous state have been
given above.

Ammonia-persulphate of uranium crystallizes like the preced-
ing salt. It is easily soluble in water, and in a higher tempera-
ture it is decomposed, leaving protoxide of uranium.

Potash-permuriate of uranium crystallizes likewise, if we add
a considerable proportion of muriate of potash to the solution of
peroxide of uranium in muriatic acid ; but unless this be done,
the double salt crystallizes very slowly. It forms small crystals,
sometimes in prisms, sometimes in grains. They are transparent
and yellow, and have a regular form ; but are mechanically mixed
with muriate of potash ; from which however they may be picked
out quite pure ; but the process is very tedious, as the crystals
are small. The mixed muriate of potash cannot be separated by
crystallizing again, for as it is just as soluble in water as the double
salt, they both crystallize at the same time. When heated, the
double salt gives out water without being decomposed. It melts
when it begins to be red-hot, giving out chlorine gae. It
becomes green, and is decomposed, though only partially.

I have not examined any other double salts, though it is likely
that more of them might be easily obtained.

Article V.

Examination of the Oxidum Mauganoso- Manganicum, a hitherto
unknown Chemical Compound of the Protoxide and Deutoxide
of Manganese. By Aug. Arfwedson.*

In consequence of the experiments which have been made
upon the oxides of manganese, it has been concluded that the

• Translated from the Athandlingar i Fysik, Kcmi, &c. vi, 222.

268 M. Arfwedson on [April,

products formed, when protoxide of mangauese is heated to
redness in the open fire, and when nitrate of manganese is
exposed to a red heat, constitute one and the same oxide ; and
that the different colours (for the former is brown and the latter
black) are owing to the different states of mechanical division in
which the two bodies are. But I have always obtained these
two products, very different from each other in appearance, even
when both were reduced to powders of the same fineness. The
former always gives with sulphuric acid a weak amethyst-red
solution ; while the latter forms with the same acid a solution
having a deep grass-green colour. These different properties
appeared to require a more accurate investigation of the chemi-
cal constitution of these two bodies. With this view 1 have, at
the desire of Prof. Berzelius, made a set of experiments, of which
I shall now give a short account.

(1.) A neutral solution of pure muriate of manganese was pre-
cipitated by bicarbonate of potash. The carbonate of manga-
nese obtained was snow-white. After being washed with boiled
and cold water, and dried in the vacuum of an air-pump with
sulphuric acid, it remained without any change in its colour.

The carbonate of manganese thus prepared was put into a
spherical cavity blown in the middle of a barometer tube,
through which a current of hydrogen gas was made to pass. As
soon as the gas had driven out all the atmospherical air, the
manganese was heated by applying a spirit-lamp to the glass
ball containing it ; and the heat was continued as long as any
water and carbonic acid gas continued to be evolved. The
powder by this process acquired a fine pistachio-green colour,
which continued till the apparatus had cooled, and the atmo-
spherical air was admitted to it, when it became greyish-green.
A little portion of this powder treated with muriatic acid dis-
solved without the least effervescence, showing that the carbonic
acid had been completely expelled.

A gramme of protoxide prepared in this way was heated in a
glass capsule over a spirit-lamp. The matter immediately took
fire, and burnt to a dark-brown oxide, which weighed 1*0735
gramme. Thus the increase of weight on 100 parts of protoxide
was 7*35 ; and as the protoxide is considered as containing
2T9 per cent, of oxygen, the brown oxide must be a com-
pound of

Manganese 72-784 100-00

Oxygen 27-216 37-39

100-000 137-39

, The 1-0735 gramme of brown oxide was boiled with nitric
acid to dryness, and heated to redness. The brown colour of
the oxide gradually changed to black, with a copious evolution
of nitrous gas, and the weight of the powder became 1-195

1824.] the Oxydum Manganoso-Mangunicum. 269

gramme. Exposed to a stronger heat in a platinum crucibl e
over a charcoal fire, the weight was reduced to 1*100 gramme.
Thus 100 parts of protoxide by this treatment increase 10 parts
in weight ; and according to the preceding statement of the
constitution of the protoxide, this black oxide is composed of

Manganese 71 100-00

Oxygen 29 40-84

100 140-84

(2.) 1-192 gramme of protoxide of manganese, prepared as
before described, left, when burnt in the open fire, 1-383 gramme
of brown oxide. According to this experiment 100 parts of
protoxide took up 7-043 oxygen, and the constituents of brown
oxide are :

Metal 100-00

Oxygen 37-45

137-45

The 1*383 gramme of brown oxide was boiled to dryness with
nitric acid, and exposed to a strong red heat in a platinum
vessel. The matter had acquired a shining black colour, and
weighed 1 398 gramme. The increase of weight this time was
so inconsiderable that it seems probable that some disoxygena-
tion had taken place. It may be presumed, therefore, that the
black oxide when exposed to a violent heat may be completely
reduced to the state of brown oxide. The heat was continued
for nearly an hour, and was as great as could be applied. The
powder now resumed its former brown colour, and very nearly
its original weight. The excess amounted only to two mille-
grammes.

To ascertain whether the black oxide can be prepared by
means of a smaller determinate degree of heat so as to give
constant results, the oxide of manganese already heated to red-
ness was again treated with nitric acid, and heated over a spirit-
lamp five different times, and the increase of weight was noted
each time. The following little table shows the result.

100 parts of protoxide had taken up

1 st time 14-4 parts of oxyeen.

2d 13-93

3d 10-52

4th 10-37

5th 10-13

The smaller augmentation of weight in the last three experi-
ments was owing to a further evolution of nitrous gas. The expe-
riments show that the true increase of weight lies between 10-52
and 10-13. We may, therefore, consider the increase of weight

270 M. Arfwedson on [Aphil,

of 100 parts of protoxide, when converted into black oxide, to
be 10*4 ; so that black oxide is composed of

Manganese 100-00

Oxygen 41*35

I conceive that I may conclude from these experiments, that
we always find the weight of oxygen in the black oxide of man-
ganese prepared by means of nitric acid, a circumstance which
is often of considerable importance in the analysis of minerals,
in which the question often is to determine the composition of a
given quantity of oxide. Perhaps the best method of proceed-
ing may be to expose the oxide to a strong red heat till it is
converted into brown oxide, the composition of which is always
uniform, and of course the quantity of oxygen in it may be
known with great accuracy.

According to the preceding experiments, the quantity of oxy-
gen in the protoxide is to that in the black oxide as 1 to \\ ; for
100 parts of the metal combine in the protoxide with 28*107
parts of oxygen, and this quantity multiplied by l-i makes
42*160. The brown oxide, on the other hand, appears from the
quantity of its oxygen tro be intermediate between the protoxide
and black oxide ; but the oxygen constitutes no multiple either
of the oxygen in the protoxide or black oxide. It must, there-
fore, be a combination of these two oxides. If this compound,
like the oxydum ferroso-ferricum be supposed so constituted
that the oxide contains twice as much metal, and three times as
much oxygen, as the protoxide, then it will be a compound of

Manganese 72-82

Oxygen 27*18

100*00
Direct experiments have given us

Manganese 72*784

Oxygen 27*216

100*000

numbers which correspond as nearly with the calculated quan-
tities as could be expected. On the other hand, we find that
this compound by calculation may be composed of

Black oxide of manganese 68-932

Protoxide of manganese 31*068

100-000

I have called this oxide oxidum manganoso-manganicum, on
account of its resemblance to the oxidum ferroso-ferricum, the
constitution of which has been explained by Prof. Berzelius in

1824-3 the Oxidum Mangano$o-Manganicum. 27 1

his Attempt to lay the Foundation of a new scientific System of
Mineralogy, p. 92.

It remains now to ascertain how far the so called grey ore of
manganese and the crystallized varieties of that mineral usually
consist of manganese in the form of superoxide, or if they may
not consist of black oxide, which we have seen gives out oxygen
gas also when heated to redness.

I. Crystallized Grey Manganmalm, from Udenas, in West

Gothland.

5*035 grammes of the pure crystallized ore was heated over a
spirit-lamp in a small retort, to the beak of which was luted a
glass tube filled with dry chloride of calcium. The matter, as
soon as the heat was applied, gave out much water, which by
degrees passed over, and was absorbed by the chloride. The
heat was continued as long as any moisture was perceptible in
the beak of the retort. The apparatus being now allowed to
cool was weighed, and the loss of weight amounted only to two
millegrammes, a loss so small that it may be overlooked. Thus
no gas had been extricated. The mineral by this exposure to
heat had lost 0*508 gramme, which may, therefore, be reckoned
the weight of the water contained in the specimen. The residue
amounted to 4*527 grammes ; of this 4*504 grammes were
exposed to a strong red heat in a platinum crucible : the loss of
weight amounted only to 0*022 gramme. Being exposed a
second time to as high a temperature as the fire could give, the
loss of weight was increased by 0*139 gramme. A third heating
diminished the weight by 0*016. When heated for the fourth
time no further loss of weight was sustained. The crystals still
retained their shape; but the colour had been changed from
black to reddish-brown, and the powder had a cinnamon-brown
colour exactly similar to the above described oxidum manganoso-
manganicum. The whole loss of weight amounted to 0*177
gramme. This, though only from 4*504 grammes, may be
taken without sensible error for the whole loss from 4*527
grammes, as the error only begins to be perceptible in the fourth
decimal place.

Thus the mineral had given

Water 0*508 or 10*08

Oxygen 0*177 3*51

Oxidum mang.-manganicum. 4*350 86*41

5*035 100*00

The small quantity of oxygen gas obtained shows evidently
that the mineral under examination cannot be a superoxide of
manganese ; and it seems plain that the manganese is in the
state of black oxide ; for we find by an easy calculation, that
the 86*41 parts of oxidum manganoso-manganicum obtained

272 M. Arfwedson on [April,

require very nearly 3*51 parts of oxygen to be converted into
black oxide. The constituents by calculation in 100 parts are,

Oxidum manganoso-roanganicum .... 86' 85

Oxygen 3*07

Water 10-08

100-00

Now the 86-85 parts of the oxidum manganoso-manganicum
contain 23-6 parts, and 10*08 parts of water contain 8-895 parts
of oxygen. Thus it appears that the oxygen in the oxide which
has been heated to redness is not a multiple of the oxygen in
the water; but if we add the 3-07 parts of oxygen driven off by
the red heat to the 23-6 which are found in that oxide, then the
unheated mineral will be a chemical compound with water,
whose oxygen is just one-third of the oxygen in the oxide. The
hydrogen of the water driven off and its oxygen, added to the
oxide, make up the constituents of the superoxide.

It is plain from the preceding experiments that the mineral
just examined is a hydrate of manganese-oxide, whose oxygen
contains three times as much oxygen as that in the water. The

formula for this compound is Mn Aq.

II. Common Grey Ore of Manganese.

a. 5-03 grammes of this mineral in powder freed from water
mechanically lodged in it were put into a small glass retort, to
the beak of which was luted a glass tube filled with dry chloride
of calcium. The retort was heated over a spirit-lamp as long as
any moisture was disengaged. The apparatus being allowed to
cool was found to have lost 0-143 gramme of its weight; this
was gas disengaged. The chloride of calcium had increased in
weight 0-077 gramme, which was water. The residue weighed
4-810 grammes.

b. Three grammes of the powder thus freed from water and a
portion of gas were exposed to a strong red heat in a platinum
crucible. After three repetitions of this process, the loss of
weight was 0-286 gramme ; and the blackish-grey colour of the
mineral was changed into brown. A fourth exposure to heat
was tried without any diminution of weight. Since 3 grammes
by this treatment lost 0-286, it is evident that if the whole quan-
tity had been thus treated, it would have lost 0-458 gramme. If
to this we add the 0-143 lost over the spirit-lamp, we see that
the 5*03 grammes of the mineral had lost 0-601 gramme of oxy-
gen and 0-077 of water.

c. The 3 grammes employed in the preceding experiment were
dissolved in muriatic acid. The solution was evaporated to
dryness, and the dry mass again dissolved in water acidulated
with muriatic acid. There remained undissolved silica and
earthy matter, which, after being washed and heated to redness,

1824.] the Oxidum Manganoso-Manganicum. 273

weighed 0*442 gramme. The filtered solution was digested with
an excess of caustic potash ; the precipitate formed was collected
on the filter and washed. The alkaline ley which passed through
was examined by the usual reagents, but it was not found to
contain any thing in solution. The precipitate by the caustic
potash was dissolved from the filter in muriatic acid. The solu-
tion, after being neutralized by ammonia, was mixed with some
drops of oxalate of ammonia, but the liquid continued clear. It
was afterwards mixed with succinate of ammonia as long as any
precipitate fell. The succinate of iron thus obtained was sepa-
rated and washed. Being; heated to redness the residual oxide
of iron weighed 0124 gramme.

As this 0*124 gramme of oxide of iron, together with the
0-442 gramme of silica and matrix, must be separated from the
3 grammes of the mineral examined, the residual pure oxide of
manganese amounts to 2434 grammes ; and consequently the
4*81 grammes of the heated mineral in a contained 3*902
grammes of pure oxide. If to this we add the 0*22 gramme of
gas and water driven off in a, the whole quantity of the mineral
freed from foreign matter was 4' 1 22 grammes, and its consti-
tuents were,

Oxygen, a . . . . 0*143
b.... 0*458

0*601 14*58

Water, a 0*077 1*86

Oxidum man.-mangan. 3*444 83*56

4*122 100*00

The small quantity of water may be considered as mechani-
cally lodged in the mineral. 83*56 parts of oxidum manganoso-
manganicum contain 22*71 parts of oxygen. Thus the remaining
60*85 parts of manganese had been united with 22*71 + 14*58,
or 37*29 parts of oxygen, which for 100 parts amounts to 61*45.

The superoxide of manganese is considered as a compound of
100 metal and 56*213 oxygen. The oxygen found in the mine-
ral, therefore, is too high ; but this is probably owing to some
error in the analysis, the principal object of which was not to
determine the constitution of the superoxide, but only to ascer-
tain if the mineral was in this higher state of oxidizement ; and
the result shows clearly that the manganese was in the state of a
superoxide.

Mineral superoxide of manganese is easily distinguished from
the hydrate by the different colours of their powders. The pow-
der of the superoxide is a full black, while that of the hydrate on
the other hand is yellowish-brown. We have only to scrape the
minerals with a knife ; the difference is immediately seen.

Protoxide of Manganese.

A globular cavity was blown in the middle of a barometer
New Series, vol. vn. t

274 On the Oxidant Mmganoso-Manganicum. [April,

tube, which was filled with pure carbonate of manganese, and a
current of muriatic acid gas was passed through it. The extri-
cation of gas took place without any evolution of heat till the
salt appeared completely decomposed. The salt was now
heated by a spirit-lamp at first slowly, but at last the greatest
possible degree of heat was given. The muriate thus formed
was rose-red, and it retained its colour, though the muriatic acid
gas driven over was at last mixed with hydrogen gas. The salt
thus obtained weighed 1*52 gramme. Being dissolved in water
there remained behind 0*012 gramme of oxide of manganese.
The remaining 1*508 was a neutral salt. The solution was quite
colourless. The muriatic acid was thrown down by nitrate of
silver, and gave, after the usual treatment, 3*408 grammes of
horn silver, which contains 0*650 gramme of muriatic acid.
This acid was combined with 0*858 gramme of protoxide of
manganese; but 0*65 muriatic acid saturate a quantity of base,
whose oxygen amounts to 0*191 ; consequently the 0*858
gramme of protoxide and manganese contain this quantity of
oxygen. The experiment gives us 100 parts composed of

Manganese 77*856 100*00

Oxygen 22*144 28*44

100*000 128*44

John, by direct analysis of neutral sulphate of manganese,
found the protoxide of this metal to contain 21*875 per cent, of
oxygen. The oxygen, according to my experiment, is a little
more ; but I have reason to conclude that a small quantity of
black oxide existed in the muriate of manganese which I
examined. The result of my experiment, therefore, may, per-
haps, be the less to be depended on.

Appendix.

That the English reader may fully understand the preceding
paper, a few observations may be necessary.

1. The atomic weight of manganese is 3*5, and the atomic
weight and constituents of its oxides are as follows :

Composition.
Atomic weight. Metal. Oxygen.

1. Suboxide . 4*0 . ... 3*5 + 0*5

2. Protoxide 4*5 3*5 + 1*0

3. Deutoxide 5*0 . ... 3*5 + 1*5

4. Tritoxide 5*5 3*5 + 2-0

5. Manganesous acid. . 6*5 .... 3*5 + 3*0

6. Manganesic acid. . , 7*5 . , , . 3*5 + 4*0

1824.] Mr. Levy on a new Mineral Substance. 275

2. The oxidum manganoso-manganicum of Arfwedson is a
compound of 1 atom protoxide and 2 atoms deutoxide.

1 atom protoxide 4-5

2 atoms deutoxide 10*0

3VL4-5

4-833

so that its atomic weight (reduced to the lowest terms) is 4-833.

3. According to Berzelius the atomic weight of manganese is
7-1157, and the names and constituents of the different oxides
are, according to him, as follows :

Composition.
Atomic weight. Metal. Oxygen.

2. Oxydule .... 91157 .... 7-1157 + 2

3. Oxide 10-1157 ....7-1157 + 3

4. Superoxide.. 10-1157 .... 7-1157 + 4

4. Berzelius represents these three oxides by the following
symbols :

1. Protoxide Mn.

2. Deutoxide Mn.

3. Tritoxide Mn.

denoting the number of atoms of oxygen by the dots above the
letters Mn.

Article VI.

Account of a new Mineral Substance. By M. Levy, MA.
in the University of Paris.

(To the Editor of the Annals of Philosophy.)

DEAR SIR, Marc/t 12, 1824.

Upon a specimen from Arendal, belonging to Mr. Turner's
collection, 1 have lately observed with cleavelandite,* flesh-
coloured felspar, and green amphibole, some small brilliant black
crystals, the description of which I now send you, because I
believe they belong to a new mineral species. Their form is

• The substance I call here cleavelandite forms the greatest part of the specimen ; it
has much the appearance of cleavelandite, but however 1 have not been able under the
small particles I have detached to obtain cleavage sufficiently brilliant tor measurement.

t2

276

Mr. Levy on anew Mineral Substance* [April,

Fig. 1.

Fig. 2.

[^5

a

\9

in

I
7*'

i ,>

/ ■•-"'

represented by fig. 2 ; in some of thern, however, the plane m
and its opposite are wanting, so that the prism is then six-sided
instead of being eight-sided. These crystals cleave easily with
brilliant surfaces parallel to the planes p and t, fig. 2. There is
also an indication of cleavage parallel to the plane m. All the
natural planes, as well as those obtained by cleavage, are suffi-
ciently brilliant to allow the use of the reflective goniometer for
the measurement of their incidences. From the measurements
I have taken, and the cleavages already mentioned, I am induced
to take for the primitive form of this substance a doubly oblique
prism, fK r . 1, in which the incidences of/) on m and t are respect-
ively 92 o0 34 / and 88°, that of m on t 112° 30', and in which the
three edges d, f, h, which meet at the solid angle o, are to each
other nearly as the numbers 13, 20, 11. The incidences of p on
m and t are nearly supplement of each other, the only difference
being 34', hence the primitive form differs but little from an oblique
rhombic prism ; for if these two angles were exactly supplement
of each other, then the incidences of p on m, and on the face
behind parallel to /, would be equal, and consequently the pri-
mitive would, at least so far, have the character of an oblique
rhombic prism. There is another incidence which might,
without a proper attention, lead to the same conclusion respect-
ing the nature of the primitive. It is the incidence of the planes
h l and g", fig. 2, which is equal to 89° 20' ; that is to say, very near
a right angle. Now if the planes g 2 and A 1 were considered as
the diagonal planes of a rhombic prism, they should be perpen-
dicular to each other. These indications of an oblique rhombic
prism, as the primitive form of this substance, are, however, car-
ried no further, and are entirely destroyed by the want of the
symmetry which should accompany them. The faces A 1 , g\ if
ihe diagonal planes of a rhombic prism, should be equally inclined
upon the two lateral planes which they meet ; and here we find
that the incidences of A 1 , with the planes m and t, as well as
those of g- with m, and the plane parallel to t, differ widely from
each other. The occurrence of the plane </' without being
accompanied by a plane replacing the edge of intersection of
plane p with the plane parallel to t, is also incompatible with an
oblique rhombic prism. No doubt can remain, therefore, as to

1824.] Mr'. Children's Examination of Babinglonite. 277

the primitive form being a doubly oblique prism. I have
thought it would not be useless to place here the discussion of
the observations which misrht lead to assume another form as
the primitive, on account of the ambiguous characters of this
remarkable form. The incidences of the planes of fig. 2 are as
follow :

(p, ■»)= 92 : 34' </>, /) = 88° (/«,n = 112° 3(f(m, h>) = 137° .7
(/, *') = 155° 25' {p, d ) = 150° 25' (g« m) = 132° 15'.

These crystals scratch glass easily. This substance I propose
to call Babinglonite, in honour of the late President, and one of
the founders of the Geological Society of London. His claims
to have his name thus recorded in mineralogy, are too manv, and
too well known to every well-wisher of this science, to require
any comment by me.

In Mr. Turner's catalogue, I had gfiven the same name to a
substance from Freyberg ; but I find that Mr. W. Phillips, in
his last work on Mineralogy, has noticed the same substance,
and designated it under the name of sulphuret of silver and anti-
mony, which name there is not the least ground to change.

Mr. Children has kindly undertaken to examine with the
blowpipe a small quantity of babingtonite.

Article VII.

Examination of Babingtonile by the Bloup>
By J. G. Children, Esq. FRS. &C;

(To the Editor of the Annals of' Philosophy.)

DEAR SIR, March 14, 1824.

In glau mairmu, the Babin^tonite decrepitates very slightly,
and gives off a dense vapour, which soon disappears. A thm
film of pure water condensed on the sides of the tube. Appear
ance of the assay not altered.

Alone, in forceps, fuses on the surface, pretty readily, into a
black enamel.

With soda, on platina wire, in the oiidatinz fame, the assay
gives a dark-cjreen opaque globule ; the addition of nitre height-
eni the colour.

In the reducing fame, the colour chanses to dark-brown, or
nearlv black ; globule opaque.

With borax. P. W. In O. F. deep amethyst-coloured 2lu-
bule ; in R. F. colour changes to bluish-green ; globule perfectly
transparent in both flames.

With salt of phosphorus. P. W. In O. F. scarcely any action

278 Col. Beaufoy' s Astronomical Observations. [April,

on a minute fragment of the assay ; globule transparent, orange-
yellow, while hot ; when cold, colourless. In R. F. the same,
but colour greenish while hot.

With the same fax, and the assay in fine powder; in O. F.
solution more easy ; but a considerable silica skeleton remains
undissolved : colour as before, but deeper. In R. F. nearly
colourless, hot; when cold, slightly inclining to an amethystine
colour. By the addition of a morsel of tin foil, the amethyst
colour a very little deeper.

With nitrate of cobalt, black mass, without any indication of
alumina.

In addition to the silica, iron, and manganese, clearly indicated
by the preceding experiments, I obtained, via humida, a consi-
derable proportion of lime. By the action of the salt of phos-
phorus, in the reducing flame, there appears to be a minute
portion of titanium present, but want of time, and a larger quan-
tity of the assay, prevented my obtaining any very decisive
results in that respect by operating in the moist way : though
they tended to strengthen the probability of its being contained
in the mineral : its quantity however must be very minute.

Article VIII.

Astronomical Observations, 1824.
By Col. Beaufoy, FRS.

(To the Editor of the Annals of Philosophy.)

DEAR SIR,
I shall be much obliged to any of your astronomical corre-
spondents, if they will favour me with their observations on the
eclipse of Jupiter s third satellite, which occurred on the 26th of
last January, as I think it is probable I committed an error by
mistaking one satellite for another, in the observations published
in the Annals for March.

I remain, dear Sir, yours very truly,

Mark Beaufoy.

Bushey Heath, near Stanmore.

Latitude 51° 37' 44'3" North. Longitude West in time V 20-93".

Feb. 21. Emersion of Jupiter's first J 9'> 39' 02" Mean Time at Bushey.

satellite ( 9 40 23 Mean Time at Greenwich.

March 3. Emersion of Jupiter's second til 08 36 Mean Time at Bushey.

satellite ^ 1 1 09 57 Mean Time at Greenwich.

March 8. Emersion of Jupiter's first < 7 58 22 Mean Time at Bushey.

satellite ( 7 9 43 Mean Time at Greenwich.

March 12. Occupation of * Leonis by the > 7 ^ 34-7 Mean Time at Bushey.

moon. Immersion y '

1824.]

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Meteorological Register for 1823.

279

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280 Meteorological Registers for 1823. [AfRiL,

Jan. — The snow continued 12 days, which is much longer
than usual.

Feb. — A very wet month.

March 4 and 5, very stormy. The gusts of wind were extremely
sudden, with wind to the NW.

April. — On the morning of the 5th, the wind changed sud-
denly from the SW to NE, and continued very boisterous till
noon : 26. Heavy hail shower, with distant thunder.

May. — A cold month, except the few last days, which were
remarkably fine.

June. — Very cold. Fires required by many in the evenings :
some thunder.

July. — Remarkably cold, wet, and boisterous ; scarcely two
days fine successively.

August. — A wet month ; much thunder and lightning on the
22d and 24th ; about two inches of rain fell in the morning of
the 24th in the course of six hours.

Oct. — The wind rose suddenly in the evening of the 30th to a
perfect hurricane, which continued throughout the night. The
barometer fell about 1 inch in about 24 hours.

Dec. 29.— Much lightning.

2. By Mr. Edward Collins Giddy, at Penzance, Cornwall.

Night and

Common

1823.

Barometer and Attached Thermometer.

Day Ther.

Therm.

Mean of the

True mean

Attached

Attached

Mean of the

Mean of

month.

of the month.

therm, max.

therm, min.

month.

month.

January . . .

29435

29-396

52

38

39-0

400

February. . .

29-355

29-311

52

42

43

43-2

29-715

29-665

52

45

46-0

451

29-700

29-638

56

48

47-0

47-2

29-740

29662

62

54

550

56-2

29-765

29-682

62

56

55-5

57-1

29-710

29-621

64

58

590

591

August ....

29-745

29-652

64

60

59-5

60-2

September .

29-840

29-750

66

56

57-5

58-0

October. . . .

29-540

29-468

62

48

51-5

53-0

November. .

29-900

29841

58

48 '

48-5

490

December . .

29-645

29-589

58

48

46-5

47-0

Annual

means, &c.

29-670

29-606

66

38

500

510

Ditto 1822

29-760

29-694

72

40

52-5

53-6

Barometer, 1823. Highest, Dec. 7, Wind, NW. 30-38; Lowest, Feb. 2, AVind,
NE. 28-45.— Day and Night Thermometer. Highest, May 29 and July 20, Wind,
S. 70° ; lowest, Jan. 16, Wind, NE. 27°.

1824.]

Meteorological Registers for 1823.

281

3. By Col. Beaufoy, at Bushey Heath.

1823.

Rain.

Evaporat.

Inches.

Inches.

January. . . .

0-976

0-310

February. . .

2-537

1-360

0-758

3020

1-950

3-300

May >
June ) * *

3-695

9610

July

3-429

3-340

August ....

2-450

3-330

September. .

2-509

3-790

October

3-076

1-890

November . .

1-644

1-200

December • .

2-258

1-280

Total

1 25-282

32-430

4. By Mr. James Stockton, at New Malton, Yorkshire.

Barom.

Ther.

1833.

Mean.

Mean.

January . . .
February. . .

29-574
89-184
29-706

31-887°

35-785

40-209

29-856

44033

29-895

54-419

29-920

54-916

July

29-711

58-774

August ....
September. .
October. . . .

29-780
29-868
29-680

57-645
52-516
45-741

November. .

30-083

42-750

December . .

29-514

36-710

Annual

means, &c.

29-732

46-282

ANNUAL RESULTS.

Barometer.

Inche*.

Highest observation, Nov. 10. Wind NE 30 880

Lowest observation, Oct. 1 1 . Wind SE 28-350

Range of the mercury 2*530

Mean annual barometrical pressure 29*732

Greatest range of the mercury in October 2* 180

Least range of the mercury in July 0*900

Mean annual range of the mercury 1*597

Spaces described by the mercury 93*180

Total number of changes in the year 154*000

282 Meteorological Registers for 1823. [ApRtL,

Six's Thermometer.

Greatest observation, May 7. Wind, variable 77-000°

Least observation, Jan. 18. Wind, NW 9*000

Range of the mercury in the thermometer 68*000

Mean annual temperature. 46*282

Greatest range in May 38*000

Least range in February 22*000

Mean annual range 29*918

Winds*

Days.

North and East 51*000

North-east and South-east 79*000

South and West 98*000

South-west and North-west 1 12*000

Variable 25*000

Rain.

Inches.

Greatest quantity, in February 7*040

Least quantity, in April 0*940

Total amount for the year 42*400

Observations.

Pressure. — The mean annual barometrical pressure (notwith-
standing the extraordinary wetness of the period, is greater than
that for many years past.

Temperature. — The mean annual temperature fully confirms
what has been before advanced, that wet summers are generally
cold ; the whole of the monthly means, with the exception of
May and December, are unusually low. Indeed the actual defi-
ciency as to the annual amount exceeds 2-^- degrees.

Winds. — These nearly agree with their respective numbers in
1 822, and what is more strikingly remarkable, those of the SW
exactly correspond.

Rain. — As to rain and snow, the amount is nearly unprece-
dented, and for the last three years it has been rapidly increasing.

1824.] On the Transmission of Electricity through Fluids. 283

Article X.

On the Effects of transmitting the Electrical through other Fluids.
By Mr. C. Woodward.

(To the Editor of the Annals of Philosophy.)

SIR ? March 12, 1824.

As every subject connected with electrical science is daily
assuming a more important feature, the following experiments
and observations may not be uninteresting to some of your
readers.

Place apiece of glass on the table of the universal discharger,
and bring the pointed wires nearly in contact upon the surface
of the glass; over the intersection formed by the wires, strew
some loose gunpowder, and pass through it the charge of a jar
containing about a square foot of coated surface, when it will be
found that the powder will be invariably dispersed without
inflammation.

Take a glass tube six or eight inches long, and about a quarter
of an inch in diameter, fill it with water, and insert a cork at
each end ; through the corks pass pieces of wire so as to form a
conducting communication with the water ; place some loose
gunpowder on the glass of the universal discharger as before,
insulate the tube, and let it form part of the circuit ; pass the
charge through the water, and the gunpowder will be inflamed.

The small degree of intensity of charge required to produce
the inflammation of gunpowder, when transmitted through a
tube of water, is surprising ; as the discharge of a quart jar
indicating only an intensity of from 10 to 15 degrees is generally
sufficient, and there appears to be little or no difference in the
effects of tubes varying from 3 to 18 inches in length.

In prosecuting my inquiries to ascertain the cause of this sin-
gular effect, I found that the charge of a jar, which, when
transmitted by a;ood conductors, was sufficient to produce the
fusion of 12 inches of iron wire, did not affect a single inch of
the same wire, when passed through the tube of water ; from
which I concluded, that the intervention of the water tube, must
have produced or prevented some mechanical effect.

I then pasted on a board, about three feet long, a narrow slip
of tin foil, in which, at equal distances, four intersections, about
one-eighth of an inch each, were made. I insulated the board,
and placed over one of the intersections some loose gunpowder,
and over each of the others six or eight wafers. On transmit-
ting in the common way a charge through the tin foil, the pow-
der was scattered, and the wafers blown three or four feet from

284 On the Transmission of Electricity through Fluids. [April,

the surface of the board ; but on repeating the experiment with
a tube of water, the powder was inflamed, and the wafers
remained without any perceptible motion. This experiment led
me to suppose, that a sufficient degree of heat under each cir-
cumstance was produced by the electrical fluid to inflame the
powder ; but when it passes through good conductors, the air is
so suddenly and violently expanded, that the powder is scat-
tered before it can be inflamed, as is the case with some of the
grains when a musket is let off (for if it be fired over snow, a
considerable portion of unconsumed powder will be perceived),
but water being a less perfect conductor than the metals, by
opposing a resistance to the passage of the electrical fluid,
retards its velocity, and thus prevents the sudden expansion of
the air, which would have scattered the powder before inflam-
mation could have taken place.

This theory explains the circumstance of the charge having
no effect upon the wires when transmitted through a tube of
water. It is well known that intensity of charge is of the great-
est importance in the fusion of wires. Now as intensity is
velocity, it must follow, if the velocity of a charge be retarded,
the intensity must be diminished ; and hence no experiment
requiring intensity of charge can be performed when the water
tube forms part of the circuit.

If the tube be filled with other fluids, it will be found that the
nearer the transmitting medium approaches to a good conductor,
the greater will be the expansive effects ; and as the expansive
effects increase, the difficulty of inflaming the powder will
increase also.

If the tube be filled with ether or alcohol, and placed in the
circuit, the powder will be inflamed. If it be filled with sulphuric
acid, which is a better conductor, the powder will be scattered
and not inflamed, but the dispersion will not be so great as when
metals only form the circuit. The same effect will be produced
by transmitting the charge through the animal economy, or
through water not inclosed in tubes, in which case the water
does not appear to oppose a sufficient resistance to the passage
of the fluid.

But the most remarkable circumstance attending these phe-
nomena is, that it is immaterial whether the tube form part of the
circuit before the electrical fluid passes the gunpowder, or after-
wards. If the tube be placed on what I will call, for the sake of
distinction, the negative side of the powder, either in immediate
contact with the powder, the coating of the jar, or in any part
of an interval in 20 yards of chain, the powder will be invariably
inflamed when the charge is passed.

In this experiment the effect appears to precede the cause ;
and it may be asked, does it not prove the existence of two
fluids ? Some would no doubt answer in the affirmative, but so

1824.] Mr. W. Phillips's Hints to an Edinburgh Reviewer. 285

many difficulties attend the introduction of two fluids, and so
many experiments militate against it, that I would refer to some
other cause for an explanation of the fact.

Every substance which may be used as a conductor possesses
a certain quantity of electricity, which, unless disturbed, remains
in a dormant or a latent state. When a charge is passed
through conductors, I conceive their natural quantity of electri-
city is driven offin the same way as water forced through tubes
tilled with the same fluid expels the water contained in them
before any more can enter; and if an impediment were placed
in any part of such tubes, the obstruction would be immediately
felt throughout. So with the electrical fluid ; the obstruction
made by the introduction of water, which is a less perfect con-
ductor than the metals, instantaneously affects the whole line of
the circuit in whatever situation the tube may be placed ; and
by retarding the velocity with which the electrical fluid moves,
prevents the expansive effects which the charge would otherwise
have produced.

I am, Sir, your obedient servant,

Charles Woodward.

Article XI.
Hints to an Edinburgh Reviewer. By W. Phillips, FLS. &c.

In the Edinburgh Review for January last, the concluding-
article is headed by the title page of the third edition of my
Elementary Introduction to Mineralogy ; but the " running
title" is, with more propriety, " Mineralogical Systems." At
the conclusion of the article, however, the Reviewer has bestowed
on my little book half a page ; and though not acquiescing in
the correctness of all his observations, I have nothing to object
against the tons and manner of the criticism.

But " there is a circumstance which merits attention, as it
affects the degree of confidence which we can place in crystal-
lographical indications" (p. 495), as reported by the Reviewer,
who proceeds thus : " Similar cleavage planes in different indi-
viduals of the same species, meet in some cases under angles of
different values. These differences are stated bu the author of
the ivork before us, as amounting even to forty minutes of a
degree."

.Now we might expect that a Reviewer should possess the
several qualifications essential to the elevated position
he voluntarily occupies, when he undertakes the task of
criticising the works of others. First, that he should under-
stand the subject ; secondly, that he should read the work he
criticises; and thirdly, that he should quote faithfully and accu-

286 Mr. W. Phillips's Hints to an Edinburgh Reviewer. [April,

rately ; but really I am compelled, though with regret, to con-
clude, that the Reviewer in question must be deficient in all
these requisites, and he must excuse me if I proceed to the
proof.

Supposing that the " author of the work before us," as the
Reviewer has it, had not known better than to assert that the
" cleavage planes of different individuals of the same species
meet in some cases under angles of different values ; " the
Reviewer ought himself to have known enough of the subject to
have enabled him to contradict the assertion, and to set the
author and his own readers right, instead of building upon so
unfounded a position, as the Reviewer has done, a sort of battery
against " crystallographical indications;" which, indeed, as the
case stands, is a very harmless one. But the Reviewer could
not have been aware of the fact, that the planes of cleavage of
different individuals of the same species do always meet at the
same angles, if the cleavages and the selection of the minerals
be made with proper care ; and I cannot refrain from advising
him to convince himself of this fact, by beginning with calca-
reous spar, sulphate of barytes, or any other of the several mine-
rals which are commonly chosen for the first attempts of the tyro
in this important and interesting department of the science.
Let him give only an hour or two to cleavage and the reflective
goniometer, and he will not fail to convince himself that if I
had said what he attributes to me, I should have mis-stated a
fact ; but as he must be unacquainted with that well-known
fact, I think it is sufficiently apparent that he must be deficient
in the first requisite — a knowledge of the subject ; that is, of
mineralogy.

The existence of the second and third requisites maybe discuss-
ed together. The place in which I have mentioned an occasional
variation of 40 minutes in angles obtained by the reflective gonio-
meter, and I believe the only place, is in the second page of the
advertisement to the third edition. Now if the Reviewer had
given a reasonable attention to the former part of the paragraph
in which that observation occurs, he would have found out that
I was speaking of the natural planes, not the cleavage planes of
crystals. My words are, " the measurements of the crystalline
forms, and especially of the secondary planes, are not precisely
exact, do not on all occasions relatively agree. — It has been
ascertained by a comparison of the measurements taken from
similar and brilliant planes oj different crystals," [the planes of
crystals can be no other than their natural planes] " that, owing
to some natural inequality of surface, the same precise angle is
rarely obtained — that the limit of error is considerably within
one degree — that it rarely exceeds 40 minutes, and that it is
frequently confined to a minute or two." And if the Reviewer
had read a few more lines of the same paragraph, he would have
been convinced, even if the above quoted words had not served,

1824.] On the Crystalline Forms of Artificial Salts. 287

to convince him, that the exceptions related solely to natural
planes ; for he would have perceived that I have said, " The
measurements obtained from planes produced by cleavage, may
be considered as approximating the truth much more nearly,
than those taken by means of the natural planes." And if the
Reviewer had condescended to peruse page xxix of the Intro-
duction, he would have found this remark ; " But if we cleave a
crystal, carbonate of lime for instance, if it be pure and transpa-
rent, we shall find, by the help of the reflective goniometer, that
the planes of the primary nucleus which will be extracted, meet
invariably under angles of 105° 5' and 74° 55'." The carbonate
of lime is here quoted as an instance, that if we cleave a crystal
[of any substance which is pure] the planes of cleavage will
meet under constant angles.

I am now content to leave the reader and the Reviewer him-
self to judge whether he possesses or not the second and third
requisites for his office. I wish, however, that he may be dis-
posed to take these hints for his future government, and believe
the fact, that personal feeling is concerned in them only in so
far as belongs to the regret necessarily accompanying a mis-
statement of one's own words. It is for the credit and utility of
cleavage and the goniometer principally, that 1 am induced
thus publicly to expose the fallacies of a Reviewer whose
dicta on mineralogical systems ought to be received with
caution, since he has attributed to an author an error of his
own, and which if he had understood the science (he must excuse
me) could not have been written.

It might not, perhaps, be very difficult to point out some
inaccuracies (to speak gently) in the Reviewer's review of the
Systems ; but with these I do not meddle. In line 21, p. 491,
there is, however, one error that must be noted for the benefit of
the Reviewer's reader. For brimstone read limestone. This
error is somewhat odd, considering the locality of its origin, and
must be ascribed to the printer, or rather one would think, to the
" printer's devil."

Article XII.

On the Crystalline Forms of Artificial Salts.
By H.J.Brooke, Esq. FRS.

{Continued from p. 162.)

Hydrate of Strontia.

From the measurement and cleavage of some crystals of this
substance received from ihe laboratory of the Royal Institution,
I find its primary form to be a right square prism. The cleavage

288 On the Crystalline Forms of Artificial Salts. [April,

parallel to P is very easy, and the planes
bright; that parallel to M and M' is less
determined, although sufficiently apparent.

P on M, or M' 90° 0'

Pone, ore' 137 48

MonM' 90

M on c 132 12

/ C \

r'\

/■■■■

>
M

! M

^

\^

\ 1

/

N^

p-

Acetate of Slronfia.

The crystals I have obtained of this salt from a solution of the
carbonate in acetic acid are very small, with rather imperfect
planes, and have not afforded distinct cleavages parallel to any
of these. There is, however, an appearance of cleavage parallel
to the plane M of the annexed figure.
From the general character of the crystals
and from measurement, a right oblique-
angled prism may be regarded as their pri-
mary form. The crystals are very efflores-
cent.

M on T 96°

/

M on d,
Mon/

107
129

M on e 153

T on e 122

d on d' 124

10'
33
20
12

58
54

>t

Nitrate of Strontia. — Anhydrous.

The primary form is a regular octahedron. The crystals gene-
rally resembling those of nitrate of lead, given in the number of
the Annals for January last.

Hydrous.

A very efflorescent salt, and not affording any distinct cleav-
age that I have been enabled to discover. We may assume an
oblique rhombic prism as its primary form. The crystals are
sometimes considerably lengthened, and
present only those planes which are marked
as the primary.

P on M, or M'

P on i, or i'

103°
111
131
66
146
150
126

40'

5

47

MonM'

M on k

20
50

M on i

10

1824.] Mr. Cooper on the Nitrates of Strontia. 289

Article XIII.

Analysis of the Nitrates of Strontia, described in the preceding
Paper. By Mr. J. T. Cooper.

(To the Editor of the Annals of Philosophy.)

DEAR SIR, March 20, 1824.

At the request of Mr. Brooke, who observed the difference
in the primary forms of the crystals of this salt, 1 have under-
taken its analysis, and for this purpose I exposed 50 grains of
the prismatic variety to a heat of 240° Fahr. for a considerable
time until it ceased to lose weight ; the quantity of water lost
was 13-9 grains, leaving 36-1 of dry nitrate ; the dry nitrate was
then dissolved, and solution of carbonate of potash added (of
known strength) until it ceased to precipitate carbonate of stron-
tia ; it required a quantity of the solution equal to 23*8 of
dry carbonate of potash ; the fluid portion now showed no trace
of the alkali, or the earth. The carbonate of strontia, when dry,
weighed 25*7, and the fluid portion evaporated to dryness left
34*7 of nitrate of potash.

From the above, it is evident the composition of prismatic
nitrate of strontia is in 50 grains

Acid 18-4 or in 100 30-8

Base 17-7 35-4

Water 13-9 27-8

50-0 100-0

This differs considerably from Kirwan who, appears to be the
only chemist who has examined this variety : he states the com-
position of it as,

Acid ; 31-07

Base 36-21

Water 32-72

The difference in the quantity of water may be in a great
measure accounted for by his not selecting perfectly formed
crystals for his experiments ; but how the variation in the pro-
portions of the acid and base could arise is much more difficult
to account for. The crystals employed by me were selected by
Mr. Brooke for the purpose.

I also obtained from Mr. Brooke some well-formed crystals of
the octahedral variety, and having weighed 14-84 grains, 1 sub-
jected them as before to heat for a considerable time ; the loss
amounted to -07 : they were afterwards heated to a much higher
temperature, but not sufficient, to decompose the salt, when a

New Series, vol. vii. u

290 Dr. Fleming on a [April,

further loss of -02 occurred ; but this loss was recovered after
the salt had stood a few minutes exposed to the air. The crys-
tals did not in the least lose their transparency ; they were then
dissolved, and solution of carbonate of potash, equivalent to
9-55 of dry carbonate, was added j the fluid portion was then
examined for alkali and earth, but showed no traces of either ;
the carbonate of strontian, when dry, weighed 10*3, and the
nitrate of potash 14*23 : its composition, therefore, is :

Acid 7-55 or in 100 50-92

Base 7-22 49-08

14-77 100-00

The small loss of water, amounting only to -07, cannot be con-
sidered otherwise than interposed water, and not in any way
attached to the formation of the crystal : the composition of
these salts may be considered as similar, excepting that the
octahedral variety contains no water of crystallization, and the
prismatic variety 27*8 per cent.

Article XIV.

On a Submarine Forest in the Frith of Tat/, with Observations on
the Formation of Submarine Forests in General. By John
Fleming, DD. FRS. Edin *

The title which I have given to this paper, is, perhaps, faulty,
and apt to lead the imagination to expect a description of the
various forms of those sea-weeds which clothe the channel of the
deep ; — the arrangement of the species, as depending on the soil
and depth of water, the food which they yield to the various
creatures that browse upon them, and the protection they afford
to such as take refuge among their leaves and branches. Very
different, however, is the scene which T propose to describe, it
being a bed of peat-moss, covered by the sea at every full tide,
but indicating, by the appearances which it exhibits, that its
present low level is different from its original position. In other
words, it is a geological phenomenon, occurring in the Frith of
Tay, similar to the one observed on the Lincolnshire coast,
which, in 1796, was examined by the late Sir Joseph Banks and
Dr. Joseph Correa de Serra, and described by the latter in the
Transactions of the Royal Society of London for 1799, p. 145,
under the title, " On a Submarine Forest, on the East Coast of
England." I venture to prefix the same title to this paper,

* From the Transactions of the Royal Society of Edinburgh, vol. ix. Part II.

1824.] Submarine forest in the Frith of lay. 291

which I now offer to the consideration of the Royal Society of
Edinburgh, aware of its impropriety, but urged by the wish to
connect similar phenomena by the common terms employed in
their description.

The bed of peat to be described, and now dignified by the
title of a Submarine Fared, occurs on the south bank of the
Frith of Tay, and has been observed in detached portions on the
west side of Flisk Beach, to the extent of nearly three miles, and
on the east side, upwards of seven miles. At this particular
place, to which the following observations chiefly apply, it rests
upon a bed of clay of unknown depth. This clay is of a grey
colour, much mixed with mica, and in some places with grains
of quartz, and resembles the carse ground on the opposite side
of the Frith, or the contents of the sand-banks which obstruct
its channel. The upper portion of this clay has been penetrated
by numerous roots, which are now changed into peat, and some
of them even into iron pyrites. The surface of this bed is hori-
zontal, and situate nearly on a level with low water-mark. In
this respect, however, it varies a little in different places. The
peat-bed occurs immediately above this clay. It consists of the
remains of the leaves, stems, and roots, of various common
plants, of the natural orders Equisetacese, Graminea?, and Cype-
racea?, mixed with roots, leaves, and branches of birch, hazel,
and probably also alder. Hazel nuts, destitute of kernel, are of
frequent occurrence. All these vegetable remains are much
depressed or flattened, where they occur in a horizontal position,
but, where vertical, they retain their original rounded form.
The peat can be easily separated into thin layers, the surface of
each covered with leaves. The lowest portion of this peat is of
a browner colour than the superior layers ; the texture likewise
is more compact, and the vegetable remains more obliterated.
The peat contains a good deal of earthy matter.

The surface of this bed of peat is nowhere (that I have
detected) covered by any alluvial stratum, nor does it occur at a
hio-her level than four or five feet below high water-mark.
Towards the shore it seems to be cut off by the old red alluvial
clay, on which the newer grey, or carse clay also rests.

The only circumstance of much interest, in reference to this
peat-bed, remains to be stated. Upon its surface may be
perceived the stumps of trees, with the roots attached, and
evidently occupying the position in which they formerly grew ;
as the roots are observed to spread, subdivide, and penetrate the
bed in their usual natural manner. 1 have counted at one time,
after a favourable tide had cleared away all silt and gravel from
the surface;, upwards of a score of those roots, situate at unequal
distances from one another, but all, by the position and arrange-
ment of their roots, demonstrating that such had been, while
growing, their original situation. To prevent any suspicion from
arising, that 1 may have been deceived on this subject, I may

u 2

292 Dr. Fleming o?t a [Apmix,

state, that the scene, situate hut a hw hundred yards from my
dwelling, has been examined repeatedly, and under different
circumstances, and several friends who have visited the spot,
have appeared satisfied of the accuracy of my conclusions. I
may mention the names of two of these, Mr. Neill and Mr. Bald,
both members of this Society, and well qualified, by habits of
observation, to form a correct opinion on the subject. Many
of these trunks and roots occur from eight to ten feet below high
water-mark.

If we assume, therefore, that the roots of these trees are in
their natural position, with respect to the bed which now sup-
ports them, are we warranted to conclude that they grew on a
surface ten feet lower than the high water-mark, but before that
surface was exposed to the periodical inundations of the tide ?
Every cavity, in this climate, situate at a lower level than that of
the sea, is invariably filled with water, and in a condition hostile
to the growth of trees, until its surface has been elevated, by the
washing in of mud, or the growth of peat, to a position at least
equal to the ordinary rise of the tide. Since these trees could
not, therefore, have grown in an inland valley so far below the
rise of the tide, even where the sea was excluded, we must draw
the conclusion that the surface on which these trees grew, was,
at the period of their growth, at least ten feet higher, in relation
to the sea, than at present ; and to account for this remarkable
change, we must adopt one of the following suppositions : —
Either that the sea has risen ten feet, and overflowed that sur-
face which was formerly beyond its reach ; or, that the ground
supporting these trees has sunk to the same extent.

The first of these suppositions, viz. a permanent rising of the
sea, has not been resorted to by a»y of those writers whom we
have had an opportunity of consulting. Indeed it is contrary to
those known laws which regulate the movements of the ocean,
and receives no support from any circumstances which have
been observed on the maritime shores of this country.

If, then, we abandon the idea that the sea has gained an
elevation of its level, and adopt the other supposition, viz. that
the peat-bed has sunk, so as now to be ten feet lower than when
the trees grew upon its surface, we advance a step nearer the
object at which we aim. It still remains, however, to be deter-
mined, what those causes were, which operated in depressing
the surface of this bed, and enabling the waves to pass over that
soil which was formerly so much beyond their influence, as to
be fit for the support of the hazel and the birch tree.

The first method of explaining the phenomenon likely to pre-
sent itself, especially where the bed is limited in extent, is by
supposing that the substratum, having lost its adhesion to the
bed on which it rested, by the percolation of water, and the
exposure of the side next the sea, moved down an inclined
plane into deep water, carrying along with it the upper layer

1824.] Submarine Forest in the Frith of lay. 293

of vegetable matter, and the trees growing upon its surface.
Such occurrences have taken place in several inland bogs, both
in Scotland and Ireland, which have moved out of their posi-
tions to a lower level. The extent, however, of this bed, and
the horizontality of its layers, prevent us from considering its
present depressed position as having been produced by any
sliding of this kind. Neither hath it arisen from the washing
away of the soft matter nn which the bed supporting the trees
rested, for the clay still remains, and at the line of junction is
much incorporated with the peat.

This washing away of the subsoil, however, has been resorted
to by Mr. Watt of Skail, to explain the conditions of a sub-
marine forest on the west coast of Orkney. It occurred to him
" that this bed of moss and trees has arrived at its present level
(so as to be covered, during the flood-tide, to the depth of at
least fifteen feet of water), in consequence of the removal of a
bank of earth, at least eighteen feet deep, which has been
washed gradually away, by the water of the Loch of Skaill
oozing along the rocks upon which it rested, and upon which
the mass of leaves now rests, held together by the fibres of the
roots of the trees." See Edinb. Phil. Jour., vol. iii. p. 101.
This explanation, however, is liable to very strong objections.
It is not probable, that, on the stormy coast of the west side
of Orkney, where the rocks themselves yield to the fury of the
waves, and where the top of every cliff is a heap of ruins, a
mass of earth, eighteen feet in thickness, would be permitted
to remain, until washed away by the slow force of percolating
fresh water, or that a continuous bed of peat, of nearly an acre
in extent, would be spared from destruction, and suffered to
settle peacefully, in the Bay of Skaill, so as to be covered at
flood-tide with fifteen feet of water.

If we have no reason to believe that this Tay-bed was trans-
ported to its present situation, in what manner has it reached
its present level ? Two solutions of this curious question have
been offered, as connected with similar occurrences, by eminent
individuals, Dr. Borlase, Dr. J. Correa de Serra, and Professor
Playfair.

Dr. Borlase, who, in 1757, observed a submarine forest at
Mount's Bay, Cornwall, covered at full tide with twelve feet
of water, considered the depression of the bed, which supported
the trees, and still contained their roots in situ, as having
arisen from subsidence of the ground, produced by earth-
quakes, or, to state it in his own words, " that there has been
a subsidence of the sea-shore hereabouts, is hinted in my
letter to you, p. 92 ; and the different levels and tendencies
which we observed in the positions of the trees we found,
afford us some material inferences as to the degree and ine-
qualities of such subsidences in general ; as the age in which

294 Dr. Fleming on a [April,

this subsidence happened (near 1000 years since at least), may
convince us, that when earthquakes happen, it is well for the
country that they are attended with subsidences.; for then the
ground settles, and the inflammable matter, which occasioned
the earthquake, has no longer room to spread, unite and recruit
its forces, so as to create frequent and subsequent earthquakes ;
whereas, where there are earthquakes without proportional
subsidences, there the caverns and ducts under ground remain-
ing open and unchoaked, the same cause which occasioned
the first has room to revive, and renew its struggles, and to
repeat its desolations and terrors ; which is most probably the
case of Lisbon." Phil. Trans. 1757, p. 52.

The views of Dr. Borlase, in reference to this depression of
the ground, in consequence of earthquakes, was evidently in-
fluenced by the curious observations which he had formerly
made on the subsidence of some places at the Scilly Islands,
as stated, Phil. Trans, vol. xlviii. p. 62 ; and other observers
may be led to form the same opinion, especially if the singular
sinking of the cliff at Folkstone, about forty feet, even in the
absence of an earthquake, be taken in consideration. See
Phil. Trans. 1786, p. 220.

Dr. Correa de Serra also ascribes the depressed position of
the submarine forest of Lincolnshire to the force of subsidence,
aided by the sudden action of earthquakes. " There is a force
of subsidence (he says) (particularly in soft ground), which,
being a natural consequence of gravity, slowly, though per-
petually operating, has its action sometimes quickened and
rendered sudden by extraneous causes, for instance, by earth-
quakes." " This force of subsidence, suddenly acting by means
of some earthquake, seems to me the most probable cause to
which the actual submarine situation of the forest we are speak-
ing of may be ascribed. It affords a simple easy explanation
of the matter ; its probability is supported by numberless in-
stances of similar events." Phil. Trans. 1709.

Professor Playfair, when contemplating the phenomena of
the Lincolnshire submarine forest, rejected the explanation
offered by Dr. Correa de Serra, and availed himself of some of
the peculiar assumptions of the Huttonian Theory of the Earth.
" The subsidence (he says) however, is not here understood
to arise from the mere yielding of some of the strata imme-
diately underneath, but is conceived to be a part of that geolo-
gical system of alternate depression and elevation of the surface,
which probably extends to the whole mineral kingdom. To
reconcile all the different facts, I should be tempted to think,
that the forest which once covered Lincolnshire, was immersed
under the sea by the subsidence of the land to a great depth,
and at a period considerably remote ; that when so immersed,
it was covered over with the bed of clay which now lies upon

1824.] Submarine Forest in the Frith of Tay. 295

it, by deposition from the sea, and the washing down of earth
from the land ; that it has emerged from this great depth till a
part of it has become dry land ; but that it is now sinking
again, if the tradition of the country deserves any credit ; that
the part of it in the sea is deeper under water at present than
it was a few years ago." Illustrations of the Huttonian Theory,
p. 453.

A careful examination of these conjectures, which had been
offered to account for the phenomena of submarine forests, soon
convinced me that the subject was still imperfectly understood.
Under this impression, I endeavoured to become possessed of
all the conditions of the problem,'.-<and now venture to offer a
solution. The opinion which I havif, been led to form has been
entertained for some years, and stated to several friends, with-
out an objection having presented itself.

If we suppose a lake situate near the sea-shore, and having
its outlet elevated a few feet above the rise of the tide, we
have the first condition requisite for the production of a sub-
marine forest.

If we now suppose, that, by means of mud carried in by
rivulets, and the growth of aquatic plants, this lake has become
a marsh, and a stratum of vegetable matter formed on the
surface, of sufficient density to support trees, we arrive at the
second condition which is requisite. This state of a marsh,
formerly a lake, is of common occurrence, more especially
where the surrounding grounds are high, and covered with soii,
for in this case the rain washes down earthy particles, and, by
spreading them on the grassy surface, renders it a more suitable
soil for the growth of trees.

In this second condition, all the strata below the outlet of
the marsh are kept constantly wet, or in a semifluid state. The
force of ordinary subsidence, aided by occasional earthquakes,
may render the whole tolerably compact ; yet the quantity of
water necessarily present, will prevent any thing like the degree
of condensation of ordinary alluvial land or soil from taking
place.

Suppose a marsh in this condition to have the level of its
outlet lowered, or rather, to have its seaward barrier removed
(an occurrence which many circumstances induce us to believe
to have happened frequently both on the east and west coasts
of this country, where submarine forests are not of rare occur-
rence), what consequences would follow t The extremities of
the strata now exposed to the sea, would at every ebb-tide be
left dry, to a depth equal to the fall of the tide. Much water,
formerly prevented from escaping by the altitude of the outlet,
would now ooze out from the moist beds, and the subsiding
force would act more powerfully in the absence of the water
which filled every pore. All the strata above low water-mark

296 Dr. Fleming on a [April,

would thus collapse, and the surface of the marsh, instead of
remaining at its original height, would sink below the level of
the sea. But the escape of the water from the strata would
not, in such circumstances, be confined to the beds situate
above the low water-line. Even those occupying a position
considerably lower, would be influenced by the change ; for
the water even in such would be squeezed out, in consequence
of the pressure of all the matter of the strata above the low
water-mark, exerted during every ebb, in the expulsion of the
water at the lowest level, thus permitting the subsidence of the
strata to take place even to the lowest beds of the morass.

In consequence of this drainage, produced by the ebbing of
the tide on those marshes, the original barriers of which have
been destroyed, there is no difficulty in accounting for the de-
pression of the surface of a marsh many feet lower than its
original level, nor in explaining the fact that Neptune now tri-
umphs where Sylvanus reigned, and that the sprightly Nereids
now occupy the dwellings of their sister Naids.

The same explanation, now offered to account for the sub-
marine forest of the Tay, seems equally applicable to those of
Mount's Bay, Lincolnshire, and Orkney. It is warranted by
the effects which we have observed to have taken place in dif-
ferent districts of Scotland, from the artificial drainage, of
marshes which had formerly been lakes, and which were in a
condition of surface fit for the growth both of willows and
alders. In some cases, where the outlet of the marsh has been
lowered perhaps ten feet, and a ditch at this new level opened
through the middle of the ground, an expectation has been
formed that the original surface would be drained of all its
moisture, and brought into an arable condition. A season,
however, has scarcely elapsed, before this deep ditch has be-
come shallow, not by the silting up of the bottom, but by the
subsidence of the neighbouring matter, in consequence of the
abstraction of the water ; and the ground which was expected
to become fit for yielding crops of grain, has returned to a
condition better suited to the growth of rushes. No provision
in these cases had been made for the effect of subsidence.

Before concluding this paper, I may take notice of a few
facts which seem to have some interest in a geological point
of view.

i. One effect of the subsidence to which I have here alluded,
is the complanation of all the vegetable remains which occur
in a horizontal position, or parallel with the surface of the bed
of peat ; while those situate vertically retain their cylindrical
shape. The vegetable remains, so common in the strata accom-
panying coal in this country, exhibit the same appearances in
similar circumstances, and lead to the conclusion, that the
matter of the strata, at the period of deposition, was in such a

1824.] Submarine Forest in the Frith of Tay. 297

condition as to admit of the mechanical effects of subsidence
taking place.

2. In the examination of the vegetable remains in this bed
of peat, and of others which have been investigated, I have
been led to conclude (contrary to the commonly received opi-
nion * ), that many of the supposed stems of reeds which occur
in a petrified state, are in tact roots. These roots, or rather
subterranean stems, such as the Arundo colorata and ph rag-
mites, Menyanthes trifoliata, and many other marsh plants
exhibit, frequently occur in beds of peat, in a dead state, and
exhibit their peculiar characters, when but few traces of the
stems to which they belonged can be detected.

3. Several changes of a chemical kind have already taken
place in this stratum of peat. The fibrous structure of much of
the vegetable matter is obliterated, small portions of the reeds,
and even of the wood, are so changed as to resemble wood-
coal ; — changes these, which plainly intimate, that a process is
going on, by which, in time, that which is now peat may be-
come coal. In the crevices of some portions of the wood I
have detected thin crusts of the blue phosphate of iron. It is
rather singular to have found some of the roots in the soft clay
changed into iron-pyrites. This change has chiefly taken place
in the bark, and in such cases the wood and pith are wanting.
In one example, however, the pith remained, and had likewise
been converted into pyrites. In many cases the clay is full of
tubular cavities, the remains of the spaces which the roots or
stems of plants once occupied. The walls of these cavities are
usually of a darker colour, and firmer texture, than the sur-
rounding matter, and have evidently undergone some change,
in consequence of the decomposition of the vegetable matter.
In some cases, the epidermis of the plant remains, in contact
with the surrounding clay, while the matter of the interior has
disappeared. Into these cavities the clayey matter enters
slowly, and fills the mould which the decomposition of the
plant has prepared. This may be regarded as a process similar
to the one which has taken place in those vegetable petrifac-
tions so common in the argillaceous and arenaceous beds
of the coal-formation, in which slate-clay, clay-ironstone and
sandstone, are exhibited under the external forms of plants.

* See Parkinson's Organic Remains, vol. i. p. 455.

298 Analyses of Boohs. [April,

Article XV.

Analyses of Books.

Philosophical Transactions of the Royal Society of London, for

1823. Part II.

(.Concluded from p. 229.)

XXVI. On the Apparent Magnetism of Metallic Titanium.
By William Hyde Wollaston, MD. VPRS.

This brief but interesting communication is as follows : —

" In an account that I lately gave of the properties of metallic
titanium, which is printed in the first part of the volume of the
Philosophical Transactions for the present year,* there is an over-
sight, which I am desirous of rectifying as soon as may be. I
have there stated that the cubic crystals of titanium, when first
detached from the iron-slag where they are found, were all
attracted by a magnet, but that when they had been freed from
all particles of iron adherent to them, they appeared to be no
longer acted upon by it.

" Having since that time been led by the observations of M.
Peschier, of Geneva, to examine this question more accurately,
I find that, although the crystals are not sufficiently attractile to
be wholly supported by the magnet, yet when a crystal is sup-
ported by a fine thread, the force of attraction is sufficient to
draw it about 20° from the perpendicular, and consequently that
the force of attraction is equal to about one-third the weight of
the metal.

" When a piece of soft iron of about the same size was made
of a cubic form (weighing half a grain), the attractive force of
the iron to the same magnet was found, in successive trials, to
lift from eighty to ninety times its weight of a silver chain
adapted to this inquiry.

" By a similar mode of trial, I found that cobalt carried from
fifty to sixty times its weight, and that a similar quantity of
nickel supported from twenty to thirty times its own weight by
the same magnet.

" From the above comparison of the magnetic forces, it is
evident that the presence of about l-250th part of iron as an
alloy in the metallic titanium, would be sufficient to account for
this power, without regarding titanium itself as a magnetic
metal ; and its origin in the midst of iron, gives every reason to
suspect that it would be contaminated by some proportion of
that metal.

" It is, however, extremely difficult really to detect the pre-
sence of so small a proportion of iron, on account of the high
qolour of the precipitates of titanium. For though it may be

• jlnntls, N. S. v. 67, vi, 222.

1824.) Philosophical Tranactiom for 1823, Part IX. 299

easy to produce an appearance of blue by using a prussiate,
which already contains iron, and is consequently better adapted
to prove the absence of iron where no blueness appears, than to
ascertain its presence, it is by no means easy to obtain the more
indisputable evidence of iron by infusion of palls. It is only by
repeated evaporation of the muriatic solution, and continued
exposure of the residuum to the temperature of boiling water,
that I have succeeded in separating enough of the titanium to
allow the blackness of gallate of iron to appear, when the efflo-
rescent edges of the dried salt are touched with infusion of galls.
" Although the quantity thus rendered sensible does not
appear in proportion sufficient to account for the magnetic force
observed, there seems more reason to ascribe it to this impurity,
than to suppose titanium possessed of that peculiar property in
a degree so far inferior to the other known magnetic metals."

XXVII. An Account of the Effect of Mercurial Vapours on
the Crew of his Majesty's Ship Triumph, in the Year 1810. By
William Burnett, MD. one of the Medical Commissioners of the
Navy, formerly Physician and Inspector of Hospitals to the
Mediterranean Fleet. Communicated by Matthew Baillie, MD.
FRS.

The curious facts to which this paper relates, having already
been detailed by Dr. Paris and Mr. Fonblanque, in their " Me-
dical Jurisprudence," vol. ii. p. 460, and the paper itself having
been reprinted in a contemporary journal, their repetition here
is unnecessary.

XXVIII. On the Astronomical Refractions. By J. Ivory,
AM. FRS.

We have endeavoured, in the following paragraphs, to convey
a general idea of the nature and contents of this voluminous and
elaborate communication, necessarily omitting the author's
mathematical details, but adopting, for the most part, his own
words.

It was known to the ancient astronomers that there is a dif-
ference between the real and apparent places of the stars, arising
from the refraction of light in its passage through the atmo-
sphere. Tycho Brahe was the first who attempted to free his
observations from the effect of this irregularity. Since his
time the astronomical refraction has become more and more an
object of attention, as it is found to have the greatest influence
on the delicate exactness of modern observations. In the course
of the last twenty years many researches on this subject have
been published by philosophers of the first note, who have
applied all the resources both of theory and practice to over-
come the difficulties which it presents. By these means our
knowledge has been greatly extended ; but the problem of the
refractions must still be considered as the most imperfect part
of modern astronomy.

The first investigation that presents itself in the problem of

300 Analyses of Books. [April,

the refractions is to find the velocity of the light at any given
height in the atmosphere. The only physical principle wanted
for this purpose is the refractive power of air according to its
density. Hauksbee first determined by experiment, that air
refracts light in proportion to its density ; and this result has
been confirmed by succeeding philosophers. There is even good
reason to think that the conclusion of Hauksbee is nut mate-
rially affected by the variable quantities of aqueous vapour con-
tained in the atmosphere at different times. Admitting then the
principle we have mentioned, we must conceive that the light
coming from the sun or from a star, moves in vacuo with a
uniform velocity until it reaches the atmosphere. It is there
deflected from its course by the spherical and concentric shells
of air it meets with, each of which acts upon it with a force per-
pendicular to its surface, and directed to the centre of the earth.
Now, as all the light enters the atmosphere with the same velocity,
and as the deflecting forces are of the same intensity at the same
distance from the common centre to which they tend ; it follows,
that the new velocities acquired by the action of the forces will
be independent of the direction of the light's motion, and will
be the same at the same distance above the earth's surface.

The ultimate deviation of the light of a star from its primitive
direction depends upon the augmentation of the velocity which
the light acquires in its passage through the atmosphere, and
likewise upon the different obliquities with which it crosses the
several strata of air. Now the first of these two things is the
same for all stars and for all constitutions of the atmosphere, for
it is the same when the density of the lowest stratum of air con-
tinues the same. But the second is different for stars, that are
differently placed with regard to the zenith, and it varies also
with the densities of the strata that compose the atmosphere.
It is, therefore, certain, that the formula of Laplace is rigorously
exact in no case whatever. But when a star is near the zenith,
the variations in the obliquity of the light in passing through the
several strata of air, are inconsiderable ; and the formula will be
nearly true. However, there is always some error, which accu-
mulates as the zenith distance increases, and will at length
become sensible. Delambre tells us, that in comparing the
observations of different days, he found errors arising from
refraction that amounted to 6" or 7" at 75° from the zenith ; and
the observations of a very accurate astronomer show that similar
inequalities are perceptible much nearer the zenith (Dr. Biinkley's
paper Phil. Trans. 1821, p. 342). Now these inequalities do uot
arise from any thing imperfect in the manner of observing : they
are undoubtedly produced by alterations in the remote parts of
the atmosphere which do not affect the barometer or thermome-
ter placed at the observatory. It appears, therefore, that the
peculiar constitution of the atmosphere has a perceptible
influence on the refraction at 75° from the zenith ; and when

1824.] Philosophical Transactions for 1823, Part II. 301

Laplace's formula is made to extend to 74°, it is carried to its
utmost limit. However mutable we may suppose the condition
of the atmosphere to be, there must be a mean state equally
removed from the opposite extremes. Now, a table of refrac-
tions that should have this mean state of the atmosphere for its
basis would be the most advantageous of any. For although,
with respect to single observations, the errors of such a table
might be as great as in some other hypotheses, yet in a nume-
rous set of observations made at different times so as to embrace
all the usual changes, the inequalities of an opposite kind would
counterbalance one another. But to a certain distance from the
zenith, Laplace's formula is sufficiently exact for practical pur-
poses ; and it has the advantage of taking away the necessity of
having recourse to precarious suppositions respecting the consti-
tion of the atmosphere.

There is no ground in experience for attributing to the grada-
tion of heat in the atmosphere any other law than that of an
equable decrease as the altitude increases. This law prevails to
the greatest heights to which we have been able to ascend. The
mean elevation for one degree of depression of the centigrade
thermometer is very nearly 90 English fathoms ; and in the
height ascended by Gay-Lussac, rather more than 4-1 miles, the
same quantity comes out equal to 95 fathoms. To this great
extent the law of a uniform decrease of temperature holds good
without much deviation from the truth. It therefore seems to
be the assumption most likely to guide us aright in approximat-
ing to the true constitution of the atmosphere. The very exact
coincidence in the properties of all the atmospheres compre-
hended in the formula assumed by Mr. Ivory, with the phaeno-
mena actually observed at the surface of the earth, accounts in a
satisfactory manner for the near approach of the refractions in
every case to the quantities determined by astronomers. It
appears that although the refractions near the zenith are affected
in a degree hardly perceptible by the peculiar constitution of the
atmosphere, yet near the horizon they depend upon the same
arrangement of the strata of air indicated by terrestrial experi-
ments. The causes in the irregularities observable in these last,
likewise disturb the celestial phenomenon in a more remarkable
manner. In measuring the height of a column of air, the acci-
dental disturbances to which the atmosphere is continually sub-
ject, are in some measure corrected by means of the tempera-
tures observed at both extremities of the column ; but in
computing the refractions, the astronomer has no guide but the
thermometer placed in his observatory. In the remote parts of
the atmosphere, there may occur innumerable changes deflecting
the light of a star from its proper course, of which he has no
intimation, and for which he can make no allowance. In com-
parison of this great source of error, we may reckon as of small

302 Analyses of Books'. I [April*

account the inaccuracies that are owing to the neglect of
moisture diffused in the atmosphere, or to our want of an exact
knowledge of the law of density in regard to temperature. There
can hardly be any other remedy than that of which astronomers
so often avail themselves, whenever an ignorance of the real
causes obliges them to assimilate the phenomena to the effect of
chance ; namely, to multiply observations in different circum-
stances, with the view of making the inequalities of an opposite
description compensate one another.

From the foregoing discussion we may draw this conclusion :
that an atmosphere constituted like that of the earth must have
an altitude of at least 25 miles in order that the refractions from
the zenith to the horizon be such as they are actually observed
to be But an atmosphere agreeing with nature in the quantity of
the refractions may be found, that shall have any proposed alti-
tude greater than the minimum quantity ; and we may infer from
the duration of twilight, that the atmosphere of the earth must
have an altitude equal to 50 miles, or even more.

XXIX. Observations on Air found in the Pleura, in a Case of
Pneumato-thorax ; tvith Experiments on the Absorption of different
Kinds of Air introduced into the Pleura. By John Davy, MD.

FRS.

A brief abstract of this paper will be found in our report of the
proceedings of the Royal Society, in the Annals for July, 1823.
Dr. Davy has added, in an Appendix, an account of a case of
pneumato-thorax, in which the operation of tapping the chest
was performed ; with some additional observations on air found
within the body ; and on the power of mucous membranes to
absorb air. The air collected in this case, by tapping the chest,
consisted of 93 azotic gas, and 7 carbonic acid gas; thus, in
composition, proving almost exactly the same as the air found
in the fatal case described in the Paper itself. Various facts are
adduced, tending to support the idea, that mucous membranes
are capable of absorbing air.

XXX. On Bitumen in Stones. By the Right Hon. George
Knox, FRS.

The results of the experiments detailed by Mr. Knox in this
paper, possess considerable interest, particularly as indicating
the propriety of instituting further researches on the subject;
and of examining stony substances for bitumen when they are
submitted to analysis : we therefore subjoin them, in a tabular
form.

1824.]

Philosophical Transactions for 1823, Part II.

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1824.] Proceedings of Philosophical Societies. 305

XXXI. On certain Changes which appear to have taken place
in the Position of some of' the principal Fixed Stars. By John
Pond, Esq. Astronomer Royal, FRS.

This communication chiefly consists of a series of tables of
observations on the stars ; confirming, in Mr. Pond's judgment,
his doctrine of their southern motion. — B.

Article XVI.

Proceedings of Philosophical Societies.

ROYAL SOCIETY.

Feb. 19. — A Series of Meteorological and Astronomical
Observations made in New South Wales, and on the Voyage to
that Country, were presented from Major-Gen. Sir T. Brisbane,
KCB. FRS.

A paper was read, " On the Semi-decussation of the Optic
Nerves ; by W. H. Wollaston, MD. VPRS."

It has been generally concluded by anatomists, and they sup-
port the conclusion from the observation of the arrangement of
the optic nerves as distinctly seen in certain kinds of fishes, that
in the human eye, the optic nerves, after passing from the
thalami nervorum opticorum, meet, and then proceed appa-
rently in union, though in reality still separate ; so that the
right eye is believed to be entirely supplied with these nerves
from the left thalamus, and the left eye from the right thalamus :
and this arrangement is called the decussation of the optic nerves.
The consideration of a particular species of blindness, however,
has led Dr. Wollaston to a somewhat different distribution of the
optic nerves. After fatigue, arising from four or five hours'
violent exercise, Dr. Wollaston was affected by a partial blind-
ness, of which he first became sensible by seeing only half the
face of a person near him, and next by seeing only the termina-
tion " son " of the name " Johnson ; " this blindness was to the
left of the point of vision in each eye ; it was not perfect dark-
ness, but merely a dark shade ; and in about fifteen minutes, it
gradually passed off, in an oblique direction upwards towards the
left. As it was referable to an affection of the nerves, Dr. W.
did not apprehend or experience any return of it, other nervous
affections being produced by fatigue. Some years afterwards
he again experienced this singular kind of blindness, without
any obvious cause, and first became sensible of it likewise by
seeing only the half of a person's face ; but in this case the right
side of both eyes was affected, and complete vision was suddenly
restored by the joy produced on receiving information of the safe
arrival of a friend from a hazardous enterprise. Dr. Wollaston
has a friend who has experienced the same affection for 6even-

New Series, vol. vn. x

306 Proceedings of Philosophical Societies. [April,

teen years past, whenever his stomach is considerably deranged :
another friend was attacked by pain at the left temple, and at
the back of the left eye, which was succeeded by this sort of
blindness on the right side of each eye ; he can see to write, —
see the paper he is writing upon, and the pen he writes with, —
but not the hand that guides the pen. The affection in this
case, Dr. W. fears, is a permanent one ; the pain first expe-
rienced seems to have arisen from some effusion causing a
degree of pressure on the brain, and the blindness from the
continuance of this pressure on the left thalamus nervorum
opticorum.

Now all these cases seem referable to the partial insensibility
of each retina, and they indicate that the left side of the retina
in each eye is supplied with nerves from the same thalamus, and
the right from the opposite thalamus; so that the nerves supplying
the former alone decussate, and not those of the right side ; an
arrangement which Dr. Wollaston calls the semi-decussation of
the optic nerves.

Dr. Wollaston proceeded to illustrate this statement of the
distribution of the optic nerves, from that observed in those of
fishes : in the sturgeon the eyes are diametrically opposite each
other, each on one side of the head, the left eye being entirely
supplied with nerves from the left thalamus of the brain, and the
right eye entirely from the right thalamus. The blindness above
described, Dr. W. remarked, does not appear to be rare, but is
seldom particularly noticed, like many other things, because it
is not understood.

This very interesting paper concluded with a short section in
which Dr. Wollaston applies the sympathy of structure in the
eyes, indicated by the effects just noticed, to the explanation of
the long agitated question respecting the cause of single vision
with two eyes. Every point in each eye is supplied with a pair
of filaments from the same nerve, and the two eyes thus sympa-
thize with each other in every point : hence arises single vision ;
and hence also the reason why infants direct both eyes in a
corresponding direction, instead of squinting.

Feb. 26. — A Catalogue was presented from the Rev. Fearon
Fallows, FRS. Astronomer at the Cape of Good Hope, of nearly
all the principal Fixed Stars between the zenith of Cape Town,
Cape of Good Hope, and the South Pole.

A paper was read, " On the various Degrees of Intensity of
the local Magnetic Attraction in different Parts of Ships ; by
George Harvey, MAS. Communicated by John Barrow, Esq.
FRS. Secretary to the Admiralty."

March 4.— William Wavell, MD. and Capt. Philip Parker
King, RN. were admitted Fellows of the Society ; the Lord
Bishop of Limerick, and the Rev. Dr. E. Maltby, Prebendary of
Lincoln, being unable to attend for admission, requested to have
their names inserted in the printed lists of the Society, which
was granted accordingly.

1824.] Royal Society. 307

A letter to the President was read, from Sir E. Home, Bart.
VPRS. entitled " Some curious Facts respecting the Walrus
and Seal, discovered in the Examination of Specimens brought
Home by the late Expeditions, from the Polar Circle."

As the late various expeditions to the northern regions had
been planned, primarily, by the President and Council of the
Royal Society, Sir Everard Home wished to lay before the
Society some curious facts which he had ascertained in the
examination of some specimens brought home by them. This
he was desirous of doing before the officers who are to proceed
on the new expeditions should have left our coasts, in order that
they might know that their exertions were important to science
in various respects, besides the grand objects of their
researches ; and that they might likewise know that the pickle or
brine in which provisions are preserved at sea is well adapted
to the preservation of the internal parts of animals, preserving
them in a better state for examination, dissection, and injection,
than when they have been long steeped in spirits.

The first discovery Sir Everard had to state was, that the
hind flipper or foot of the walrus is provided with means for
enabling the animal to walk in opposition to gravity precisely
analogous to those possessed by the fly, and the use of which
could not have been suspected, had not the previous discovery
been made respecting the latter animal, as described in the
Phil. Trans, for 1816. Sir Everard at once recognized this
structure on seeing a mutilated foot of the walrus, and, in con-
sequence, had requested his friend Capt. Sabine to procure him
a specimen of the animal, which Capt. S. had accordingly
done, with the aid of the assistant-surgeon of the vessel in
which he sailed. The examination of this specimen showed,
that in the hind foot of the walrus there is a cup for enabling
the animal to produce a vacuum, and thus to walk in opposition
to gravity exactly like the two cups with which the fly's foot is pro-
vided. The apparatus in the latter required magnifying 100 times
to make the cups distinctly visible, but in the walrus it was dimi-
nished four times to bring it within the compass of a quarto plate.
The author, when writing his former papers on the fly's means
of progression, had not been able to determine the use of the
two points in the foot of that animal ; Mr. Adams had called
them pickers, and had supposed that they were inserted in the
cavities of the surface over which the animal was walking, and
thus retained it in opposition to gravity, — an opinion which
Sir Everard Home deemed undeserving of consideration ;
though he could not assign any use to the points in question.
In the foot of the walrus, however, it is evident that the two
toes which answer to the points in that of the fly are used for the
purpose of bringing the web closely down upon the surface
traversed, so as to enable the animal to form a more perfect
vacuum, and that the air is re-admitted on their being lifted up.

x2

308 Proceedings of Philosophical Societies. [April,

This part of the paper was illustrated by a drawing by Mr.
Bauer; and it was singular, Sir Everard observed, that that
gentleman should have had to delineate the same organ in two
such different animals.

The second fact described in this paper also relates to the
walrus. The bile in this animal is received from the liver by a late-
ral communication into a cylindrical reservoir, with much mucus
in its coats, and is thence impelled with considerable force into
the duodenum. The oesophagus is wide, admitting of large masses
of food being swallowed, and of regurgitation : the opening
of the pylorus is small and valvular, preventing the passage of
its contents back again into the duodenum : the structure of the
duodenum, pylorus, and adjacent organs, is very similar to that
of those of the seal. It had been observed by Mr. Fisher, the
astronomer to the late expedition under Capt. Parry, that the
food of the walrus is the fnais digitaius, which is found in
great abundance in the Arctic seas, thrown up on the shores
by the waves, and also beneath the ice.

The third fact to which Sir Everard Home adverted in this
communication relates to the structure of the funis and placenta
of the seal, as observed in a specimen of those parts brought
home by Lieut. Griffiths, one of the officers in the late expedition
under Capt. Parry. The vessels composing the former are not
twisted, and are about nine inches long ; at the distance of three
inches from the placenta, they anastomoze into blood-vessels,
which are connected with the placenta by three membranous
coats ; the whole conformation giving great freedom to the
embryonic circulation. Drawings of this subject and that last
noticed, made by Mr. Rose, a pupil under the author at St.
George's Hospital, were annexed to the paper.

A communication was likewise read, entitled " Some further
Particulars of a Case of Pneumato-thorax ; by J. Davy, MD.
FRS." Of this we shall give an account in our next.

ASTRONOMICAL SOCIETY.

Feb.13. — This day being the fourth anniversary of the Society,
a numerous meeting of the members took place at the apart-
ments in Lincoln's Inn Fields ; when a very satisfactory report
upon the state of the Society's affairs and proceedings during
the last year was read, and ordered to be printed. This report
paid a due tribute of respect to several members whom the
Society has lost by death in the last year, and particularly to
Col. W. Lambton, of Madras, and Dr. Walbeck of the Observa-
tory at Abb. It gives a succinct account of the measurement
of the largest continuous arc of a meridian yet effected, which
occupied the former gentleman upwards of twenty years in
India.

The Chairman (Mr. Colebrooke) then proceeded to distribute
the honorary rewards of the Society, viz. the Society's gold
medal to Charles Babbage, Esq. FRS. as a token of the high

1824.] Geological Society. 309

estimation in which it holds his valuable invention of an engine
for calculating mathematical and astronomical tables, being the
first medal awarded by the Society. A similar gold medal to
Prof. J. F. Encke, Director of the Observatory at Seeberg, in
Gotha, for his investigations relative to the comet which bears
his name, and which led to the rediscovery of it in 1822. The
silver medal of the Society to Prof. Charles Ruuiker for the
rediscovery of Encke's comet, and a similar medal to M. Jean
Louis Pons, of La Marlia, in Italy, for the discovery of two
comets on the 31st of May and 13th July, 1822, and for his
indefatigable assiduity in that department of astronomy. The
chairman prefaced the presentation of each medal by a most
eloquent, learned, and interesting address of considerable length,
all of which were delivered in the most impressive manner. Thev
were replete with information on the successive improvements
in machinery for assisting calculation, as well as on cometary
astronomy, and we were happy to find, that in consequence of a
motion made by Davies Gilbert, Esq. MP. and seconded by
.John Fuller, Esq. they will be printed for circulation among the
members.

The election for the Officers and Council of the Society for
the ensuing year then took place, when the following appeared
to be the unanimous choice of the meeting, viz. : —

President. — H. T. Colebrooke, Esq.FRSL. and E. and FLS.

Vice-Presidents. — C. Babbage, Esq. MA. FRSL. and E. ;

F. Baily,Esq. FRS. and LS. ; Sir B. Hobhouse, Bart. FRS.;
and The Right Hon. George Earl of Macclesfield. FRS.

lreasiirer. — Rev. W. Pearson, LLD. FRS.

Secretaries. — O. G. Gregory, LLD. Prof. Math. Roy. Mil
Acad. Woolwich; J. Millington, Esq. FLS. Prof. Mech. Philos.
Royal Institution.

Foreign Secretary.— J. F. W. Herschel, Esq. MA. FRSL.
and E.

Council.— Major T. Colby, Roy. Eng. LLD. FRSL. and E. ;

G. Dollond, Esq. FRS.; Bryan Donkin, Esq. ; Capt. J. Frank-
lin, RN. FRS.; D. Gilbert, Esq. MP. VPRS. FLS.; B. Gom-
pertz, Esq. FRS.; S. Groombrid»e, Esq. FRS.; and D. Moore,
Esq. FRS. SA. and LS.

Several new members and associates were nominated, and the
greater part of the Society adjourned to Freemasons' Tavern,
where a dinner was provided.

GEOLOGICAL so CI ETY.

Dec. 19, 1823. — A paper was read, containing Geological
Observations collected on a Journey through Persia from Busli-
ne in the Persian Gulph to Teheran ; by .lames B. Fraser, Esq.
MGS. ^

The author is of opinion that both the east and west sides of
the Persian Gulph to a great extent, consist of a calcareous

310 Proceedings of Philosophical Societies. [April,

formation, which, it is ascertained, in many parts continues far
inland. In a part of this formation, his route from Bushire com-
menced ; between which place and Shiraz, the hills are composed
of sulphates and carbonates of lime, and the strata often much
disturbed. Through a large tract of this country, carbonate of
lime is intermixed with the gypsum, but in parts, rocks of pure
gypsum occur, and very frequently accompanied by salt.
Streams and lakes of salt abound, and there is a considerable
one of the latter at Shiraz. Proceeding northward, the route
from Shiraz to Ispahan, a distance of about 250 miles, lies over
an elevated country, the nature of which is similar to that before
described, but the carbonate of lime predominates. Between
the village of Gendoo and the town of Yes-dikhaust, Mr. Fraser
found clay slate, and a conglomerate rock inclosing pebbles of
quartz, greenstone, and limestone, cemented by carbonate of
lime ; strata of this aggregate rock alternate with a finer sand-
stone. The mountains between Ispahan and Teheran are of a
character very different from the preceding ; among them clay
slate was observed, and the highest region, which reaches a great
elevation, consists of granitic rocks.

Jan. 2, 1824. — A paper was read " On the Geological Struc-
ture of St. Jago, one of the Cape de Verd Islands; by Major
Colebrooke."

From the observations of the author, and the accompanying
specimens, it appears that at the landing place near the town of
Porto Prago, in St. Jago, the rock of the cliff is composed of
fragments of trap imbedded in a hard pure white carbonate of
lime. The fragments of this breccia are generally small, and
none of them rounded by attrition. The cliff on which stand the
batteries and town of Prago, is regularly stratified, and at the
bottom are beds of a calcareous sandstone alternating with
others which contain specimens of a large oyster; in both of
these beds occur pebbles of trap. The stratum which crowns
the cliff is from eight to twelve feet in thickness, and consists of
trap.

Jan. 16. — A paper entitled " Outline of the Geology of the
South of Russia; by the Hon. William T. H. Fox Strangways,
MGS." was read in part.

Feb. 6. — On this day, being the anniversary of the Society, the
following gentlemen were chosen as Officers and Council for the
year : —

President.— Rev. W. Buckland, FRS. Prof. Geol. and Min.
Oxford.

Vice-Presidents. — A. Aikin, Esq. FLS.; J. Bostock, MD.
FR. and LS. ; G. B. Greenough, Esq. FR. and LS. ; and H.
Warburton, Esq. FRS.

Secretaries.— C. Lyell, Esq. FLS. ; P. B. Webb, Esq. FLS. ;
and T. Webster, Esq.

Foreign Secretary. — H. Heuland, Esq.

1 824.] Meteorological Society. 3 1 1

Treasurer. —J. Taylor, Esq.

Council.— Sir T. D. Acland, Bart. MP. ; J. Duke of Bedford,
FL. and HS. ; W. Clift, Esq. FRS. ; H. T. Colebrooke, Esq.
FR. and LS. ; Major T. Colby, LLD. FRS. L. and E. ; T. Hors-
field, MD. FLS.; Sir A. Crichton, MD. FR. and LS. ; C.
Stokes, Esq. FRA. and LS. ; T. Smith, Esq. FR. and LS. ;
W.H.Pepys, Esq. FR.L.and HS.; Rev. Adam Sedgwick, MA.
FRS. Woodwardian Prof. Cambridge ; W. H. Fitton, MD.
FRS.

Keeper of the Museum and Draughtsman. — T. Webster, Esq.

Feb. 20. — A notice was read, of the Discovery of a perfect
Skeleton of the Fossil Genus hitherto called Plesiosaurus ; by
the Rev. W. D. Conybeare, FRS. MGS.

The Plesiosaurus, which is the subject of this notice, was
found in the blue lias of Lyme Regis, in Dorsetshire. In the
whole exterior portion of its vertebral column the skeleton is
entire, and of the remaining parts of the animal few are wanting.
In the Transactions of the Geological Society, vol. 5, and vol. 1
second series, the author had attempted to assign to the various
dispersed and disjointed remains of this animal which were then
known, their relative places in the skeleton, and his opinions, he
observes, have now, in all essential points, received full confirm-
ation. After pointing out the errors into which he had fallen,
Mr. Conybeare describes the osteology of this remarkable fossil
animal; the most characteristic and distinguishing features of
which are, the extraordinary length of the neck, which fully
equals that of the body and tail united, and the number of its
vertebrae, which very far exceeds that of any animal previously
known.

METEOROLOGICAL SOCIETY.

Jan. 14. — The Committee appointed by the Council of this
Society to consider and report upon the best means of establish-
ing correct and complete series of meteorological observations
having presented their Preliminary Report, it was communicated
by the Council to the Society, at this meeting.

The Committee represent in this Report, that the first and
principal object of the Society is to obtain accurate and compa-
rable observations of atmospheric phenomena from all parts of
the world ; and after adverting to the advantages which would
result from the general adoption by meteorologists of instru-
ments graduated upon the same scales, to be examined by all at
the same hours, and the results noted upon the same plan, they
proceed as follows :

"The Committee are, however, aware, that there are many and
weighty difficulties in the way of such an arrangement, and that
much time would necessarily be required for their consideration
and discussion; they therefore recommend that immediate
measures be taken to procure correct registers of comparable
observations from different parts of Great Britain and its colo-

312 Proceedings of Philosophical Societies . [April,

nies, as well as from other parts of the world, with instruments
graduated to the common scales. To effectuate this purpose
with advantage, they consider it absolutely necessary that the
Meteorological Society of London should set the example of the
requisite precision by establishing a Meteorological Observatory
in the metropolis, or its vicinity, and instituting operations to be
conducted with undeniable accuracy, and with instruments of
standard excellence."

A paper was read " On the Natural History and probable
Causes of the Vernal Winds of the North of England, as they
prevail in Westmoreland ; by John Gough, Esq. of Kendal.
Communicated by Dr. Birkbeck, President of this Society."

In this paper, Mr. Gough minutely describes the phaenomena
which accompany and characterise the periodical easterly winds
of spring, especially as they prevail in Westmoreland, and
states the following opinion respecting their cause, with
various illustrations of it. The cause of these winds may
be referred to the progressive advances of the spring from the
south to the north. This season commences in Italy about the
20th of February ; it is equally advanced in Westmoreland
about the middle of April, at which time the countries situated
on the confines of the Arctic Circle remain buried in snow.
This covering will unavoidably arrest the progress of spring in
its advances towards the Arctic Circle, and prolong a milder
kind of winter in the northern regions. The delay here pointed
out is certain and annual, because the solar heat, instead of
warming the surface of the country thus buried in snow, is
absorbed by the icy covering, and employed in converting it into
water of the temperature of melting ice. While the sun is
employed in removing this impediment to vegetation in the
north, his beams are warming the plains and valleys of England,
in consequence of which the thermometer in the shade frequently
stands between 60° and 70° at noon, during the latter part of
April, and falls occasionally to the freezing point in the night.

These facts show that the inhabitants of Britain enjoy an
advanced state of temperature, while the people of Sweden and
Norway are exposed to a degree of cold equal to the rigours of
our winter. The preceding difference in the temperature of the
atmosphere of Britain and the more northern regions gives a
greater specific gravity to the air of Sweden and Norway than
to that of England, as well as all the intervening countries that
are free from snow ; and this excess of density is, in Mr. Gough's
opinion, the cause of the vernal winds.

Several other communications were likewise read.

MEDICO-BOTANICAL SOCIETY.

Jan. 15. — The Medico-Botanical Society of London held their
anniversary meeting, when the following Council was elected
for the ensuing year, viz. : —

1824.] Scientific Intelligence. 313

Dr. Bree, FRS. President ; Dr. Paris, FRS. ; Dr. E. T.
Monro ; J. Brookes, Esq. FRS. ; W. T. Brande, Esq. FRS. ;
Sir J. Mac Gregor, MD. FRS.; Sir A. Crichton, MD. FRS.
Vice-Presidents ; W. Newman, Esq. Treasurer ; Mr. C. Hold-
stock, Secretary; J. Frost, Esq. Prof . of Botany ; T. Jones,
Esq. ; W. Yarrell, Esq. ; T. Andrews, Esq. ; A. White, Esq. ;
Dr. J. Elliotson.

Article XVII.

SCIENTIFIC INTELLIGENCE, AND NOTICES OF SUBJECTS
CONNECTED WITH SCIENCE.

I. Improvement in the Mountain Barometer.

Mr. Newman has proposed to remedy the inconveniences of the
common instrument: what rhese are, and the mode of removing them,
we shall give in his own words : —

" The object has been to correct those defects and errors which arise
from the use of a wooden cistern and leather bag, in the common
barometer. It has been found that when the cistern is made of a wood
sufficiently sound and close-grained to permit of the pressure required
from the screw to make the instrument portable, that it is so imper-
vious to air, as not to allow it to pass with sufficient freedom, and con-
sequently, that when the instrument is used at any great altitude, the
mercury cannot fall into the cistern except with considerable difficulty,
and a long time is required before an accurate observation of the air's
pressure can be made; most generally, however, the cistern is suffi-
ciently pervious to air, but it is then found that on screwing up the
mercury to the top of the tube, a portion of the metal generally makes
its' way through the wood, thus soon rendering the instrument quite
useless ; for it is very evident that a barometer that loses a portion of
mercury from the cistern by making it portable or otherwise after it
is adjusted, can no longer be correct, or give the height of the column.

" To obviate these inconveniences, I have substituted a cistern of
iron in place dfth'j wooden one ; it is fastened to the tube by a thick
collar of wood, which is glued on in the usual manner ; a screw passes
through the centre of the bottom, so as to move in a line with the ba-
rometer tube ; it is terminated inside the cistern by a piece of cork tied
over with leather, so that the instrument being inclined that the tube
may be filled with mercury, this cork may be screwed up against the
end of the tube, and effectually preserve the metal within from oscilla-
tion, without subjecting the cistern itself to any pressure.

" As there is no pressure on the mercury in the cistern, the wooden
cap may be left so porous in one part, as to allow of the ready access
of air, so that the column shall fall freely to its proper level, without
any danger of losing mercury.

" Another great object in a mountain barometer, is to obtain the
temperature of the mercury, which is done by fixing a thermometer

314 Scientific Intelligence. [AiPttll>

with the bulb in the cistern ; I have found that by carrying a barome-
ter in my hand and near the bodj r , the temperature is increased consi-
derably, and will frequently rise as high as 85° Fahr. _

" In the barometer of common construction, the height of the column
of mercury is marked offfrom another instrument, presumed as a stand-
ard, and in that case, the actual height is rarely or ever given, for
every change that takes place in the weight of the atmosphere, alters
barometers more or less according to the proportion which the diame-
ters of the tubes bear to those of the cisterns, and for that reason, upon
examining twenty barometers no two will agree, unless they were
marked off together, and happen to stand at that exact height.

" To remedy this source of error each instrument may be reckoned
a standard, the height of the column is marked off from the surface of
the mercury, and the point given at which it was marked off; when
with the correction for the capacities of the tube and cistern, and also
the temperature, the actual height of the barometer is ascertained.
Upon examining the first four which I made independent of each other
on this principle, one for Mr. Daniell, one for the Royal Society, and
two for Capt. Sabine, they agreed within '004 of an inch with each
other." — (Institution Journal, xvi. 277.)

II. Vegetable Alkalies.

Mr. Brande has lately given analyses of several of these bodies, some
of which differ much from those of MM. Dumas and Pelletier, men-
tioned in the Annals for Januaiy. The most remarkable discrepance
is in the analysis of cinchonia. The mean of Mr. Brande's analyses
gives as its constituents

Carbon 79*30

Azote 1372

Hydrogen 7*17

100-19

This substance, according to MM. Dumas and Pelletier, contains
oxygen, and consists of

Carbon. . 7(y97

Azote 9-02

Hydrogen 6'22

Oxygen 779

10000

The following, Mr. Brande states as an approximation only to the
correct proportions of the elements of quina :

Carbon 7380

Azote 13-00

Hydrogen 7-65

Oxygen 5 55

100-00

1824.] Scientific Intelligence. 315

MM. Dumas and Pelletier find its constituents to be:

Carbon 7502

Azote 8-4.5

Hydrogen 6 - 66

Oxygen 10*43

100-56

The differences in the proportions of azote and oxygen are very
considerable.

In the analysis of morphia, the agreement is much greater than
could have been expected from the great differences noticed in cin-
chonia and quina. Mr. Brande gives as the elements,

Carbon 72-0

Azote 5 5

Hydrogen 5'5

Oxygen 17'0

1000

while MM. Dumas and Pelletier state its composition to be:

Carbon 72-02

Azote 5-53

Hydrogen 7*01

Oxygen 14 # 84

9940

According to Mr. Bussey {Annals, N. S. vi. 229) ,morphiais composed of

Carbon 690

Azote 4-5

Hydrogen 6 5

Oxygen 20-0

100-0

In this analysis there is a difference of more than five per cent, in
the quantity of oxygen compared with that in the last quoted; but
while MM. Dumas and Pelletier differ from Mr. Brande in assigning
nearly eight per cent, of oxygen to cinchonia, they and M. Bussey
differ from Dr. Thomson in stating azote to be one of the constituents
of morphia, and, according to him, it is composed of

Carbon 44-72

Hydrogen 559

Oxygen 49*69

100-00

From the different statements which have been thus made with
respect to the composition of these vegetable alkalies, it appears pro-
ble, either that different substances have been employed under the
aame name, or that impurity must have been in some cases mixed with
them ; if the difference existed as to the quantity of any other element
instead of the presence of azote, it might, perhaps, be referred to moist-
ure, or water of crystallization ; but as the case stands, further experi-
ments are necessary.

316 Scientific Intelligence. [April,

III. Dcebereiner's Eudiometer.

Prof. Dcebereiner having suggested the use of finely divided platina
for the purpose of detecting minute portions of oxygen in a gaseous
mixture, in which hydrogen also is present, Messrs. Daniell and Chil-
dren mixed 20 measures of atmospheric air, with 37 measures of hydro-
gen gas, and passed up to the mixture a small portion of the platina
powder, procured by heating the ammonia muriate to redness, and
made into a ball with precipitated alumina. The pellet was heated red
by the blowpipe, immediately before it was used ; its size about that of
a small pea. The absorption amounted to 13 measures = 4'3 oxygen,
being 01 of a measure more than the quantity of oxygen in 20 mea-
sures of atmospheric air, which may probably have arisen from a slight
impurity in the hydrogen, or from some minute unperceived bubbles
of air, entangled in the mercury.

Another mixture of common air and hydrogen, in which the latter
was in considerable excess, was deprived of its oxygen by the pellets,
and when the absorption was complete, 38 measures of the residual gas
were taken, and a fresh pellet, heated to redness, immediately before
it was used, passed up. After standing about a quarter of an hour, no
absorption had taken place. The tube and the mercury were then
placed before the fire, till the whole apparatus was too hot to be
touched with the naked hand. It was then removed from the fire, anil
when cooled to its original temperature, the mixture occupied, as
before, exactly 38 measures. The powder of platina with hydrogen
seems, therefore, to be admirably calculated for eudiometrical purposes.
Its application is extremely simple and easy, it is speedy in its effect,
and no error need be apprehended from the formation of ammonia,
even at considerably elevated temperatures. It appears also to be
well calculated for ascertaining the purity of simple gases, at least as
far as regards admixture of atmospheric air. The oxygen of a very
minute portion of common air, mixed with carbonic acid gas, and a
little hydrogen, was immediately absorbed, on passing up one of the
little pellets to the mixture. — (Institution Journal, xvi. 374-.)

IV. A T tu> Minerals.

Mr. Brooke has lately described two new mineral bod'es ; to the
first he has given the name of Childrenite, on account of the attention,
among other inducements, which Mr. Children has shown to mineral-
ogical chemistry. This mineral was met with in Devonshire, and was
said to have been taken from some part of the ground which had been
perforated for the Tavistock canal ; it was supposed at first to be car-
bonate of iron ; but Dr. Wollaston determined that it was a phosphate
of alumina and iron.

The primary form of the crystal is assumed by Mr. Brooke to be a
right rhombic prism ; but he has not succeeded in cleaving it. The
crystals scratch glass ; their colour is wine-yellow, they occur on the
surface of crystallized quartz, and might be mistaken by a casual
observer for sulphate of barytes.

The next mineral was sent, among other Vesuvian substances, to
Mr. Brooke by Dr. Somerville, from which circumstance he has named
it Somervillite ; the primary form of the crystal is a right square prism,
but the crystals are modified by numerous secondary planes ; they may

1824.] Neto Scientific Books. 317

be cleaved parallel to the terminal planes, but imperfectly, if at all,
parallel to the lateral planes, or to the diagonals of the prism; their
colour is a very pale dull-yellow ; they occur in cavities, with crystal-
lized black mica, and with another substance not yet examined; the
mass to which they adhere appears to be nearly all Somervillite, inter-
mingled with black mica.

This substance might at first view be mistaken for idocrase ; but it is
much softer ; the cleavage parallel to the terminal planes much more
distinct, and the cross fracture more glossy. Mr. Children has also
compared the characters of this mineral under the blowpipe with those
of idocrase. When exposed alone in the forceps, it slightly decrepi-
tates, which idocrase does not, and fuses, with greater difficulty than
idocrase, into a greyish glass, the globule from idocrase being greenish.
With borax, in the reducing flame, idocrase produces a light-green,
and this a colourless glass.

Mr. Brooke has likewise examined the mineral called hipferschaum
by the Germans, of which he had not met with any analysis. This
mineral, which is the same as the fibrous or flaky bright-green substance
found at Matlock, appears to be a carbonate of copper and zinc. —
(Institution Journal, xvi. 274?.)

V. Death of Mr. Botvdich, in Africa.

It is with unfeigned regret that we announce the death of this enter-
prising and accomplished traveller : he has fallen a victim to his over
exertions in surveying St. Mary's River, in Gambia : he expired,
after lingering a fortnight, on the 10th of January, leaving a widow
and three children totally unprovided for. We are happy to learn that
proposals will shortly be issued for publishing, for their benefit, Mr.
Bowdich's " Excursions in Madeira and Porto Santo," a work which
he had completed prior to his decease.

Article XVIII.
NEW SCIENTIFIC BOOKS.

PREPARING FOR PUBLICATION.

Elements of Physiology, by J. Bostock, MD. is nearly ready.

Capt. Sir Henry Heathcote, RN. has in the press, a Treatise on
Staysails for the Purpose of intercepting Wind between the Square
Sails of Ships and other Square-rigged Vessels : illustrated by suitable
Diagrams, and Plates.

A Treatise on the Nature, Symptoms, and Cure of Cataract ; by
John Stevenson, FRCS. 8vo.

A Treatise on Mineralogy, by Frederick Mohs ; translated from the
German by W. Haidinger. 2 vols, post Svo.

Extracts from a Journal written on the Coasts of Chili, Peru, and
Mexico, in the Years 1820, 1821, and 1822 ■ by Capt. Basil Hall, RN.
Author of a Voyage to Loo Choo. 2 vols, post 8vo.

318 New Patents. [April,

JUST PUBLISHED.

A Second Letter to Sir John Cox Hippesley, on the Mischiefs inci-
dental to the Tread-Wheel, as an Instrument of Prison Discipline,
containing an Examination of the Official Reports upon this Subject,
returned to the Secretary of State's Office, during each Session of
Parliament. By John Mason Good, MD. FRS. &c. Price 2s. 6d.

The West India Colonies : the Calumnies and Misrepresentations
circulated against them by the Edinburgh Review, Mr. Clarkson, Mr.
Cropper, &c. examined and refuted. By James Mac Queen. 8vo.

125.

The Pupil's Pharmacopoeia; being a literal Translation of the New
Edition of the London Pharmacopoeia, &c. By W. Maugham,
surgeon. 6s.

Sketches of the Philosophy of Apparitions ; or an Attempt to trace
such Illusions to their Physical Causes. By S. Hibbert, MD. FRSE.
&c. 10s. 6d.

The English Flora. By Sir James E. Smith, President of the Lin-
nsean Society, &c. Vols. 1 and 2. ll. 4s.

The New Pharmacopoeia of the Royal College of Physicians of
London, 1824; translated by Sir George L. Tuthill, Kt. MD. FRS,
8vo. 7s. 18mo. 4*.

Gardner on Iodine. 8vo. 4s.

Article XIX.
NEW PATENTS.

G. Pollard, Rupert-street, St. James, Middlesex, brass-founder, for
certain improvements on machines for levigating or grinding colours
used in the various branches of painting, which machinery may be
worked by any suitable power, and is applicable to other useful pur-
poses. — Jan. 19.

J. Russel, Wednesbury, Staffordshire, gas-tube manufacturer, for his
improvement in the manufacture of tubes for gas and other purposes.-—
Jan. 19.

S. Broadmeadow, Abergavenny, Monmouthshire, civil engineer, for
his improved method of manufacturing and purifying inflammable gases
by the admission and admixture of atmospheric air. — Jan. 19.

H. Fletcher, Walsall, Staffordshire, saddler's ironmonger, for certain
improvements in tanning hides and other skins. — Jan. 19.

T. Bewley, Mount Rath, in Queen's County, Ireland, cotton manu-
facturer, for certain improvements in wheeled carriages. — Jan. 24.

J. Heathcoat, Tiverton, Devonshire, lace manufacturer, for certain
improvements in the method of figuring or ornamenting various kinds
of goods manufactured from silk, cotton, or flax. — Jan. 24.

J. Jones, Leeds, Yorkshire, brush manufacturer, for certain improve-
ments in machinery and instruments for dressing and cleansing woollen,
cotton, linen, silk, and other cloths or fabrics. — Jan. 27.

Sir W. Congreve, Bart. Cecil-street, Strand, for his improved method
of stamping. — Feb. 7.

1824.]

Mr. Howard's Meteorological Journal.

319

Article XX.

METEOROLOGICAL TABLE.

1

Barometer.

Thermometer,

1824. "Wind.

Max.

Min.

Max.

Min.

Evap.

Rain.

2d Mon.

Feb. 1

S E

30-20

30-11

45

25

__

2 E

30-27

30-20

43

24

—

3S E

30-20

29-89

45

32

—

07

4l W

2997

2989

49

35

—

16

5| W

30-20

29-97

43

32

—

6'N W

30-29

30-20

45

32

—

,

7S W

3037

30-29

49

45

—

— —

s w

30-50

3037

54

48

—

_

9 Var.

30-50

30-48

52

35

—

—

-OS w

30-48

30-44

51

31

—

-

UN W

30-44

30-16

46

32

__

,

12 s \v

30.16

29-42

45

35

•45

12

13

W

2942

29-05

48

57

—

1-04

14

w

2960

2905

45

32

—

02

15

N E

2975

29-60

42

26

—

16"

N

2975

29-61

43

28

—

J7

N E

29-61

29-50

42

29

—

18

E

29-57

29-50

45

34

—

06

1.9 E

2966

29-57

45

37

—

10

20 E

29-91

2966

47

36

—

33

21S W

30-04.

29-91

42

30

—

22

E

30-12

30-04

47

39

—

0?

23 E

30-12

30-12

42

38

24 E

30- 12

29-98

43

27

—

25| E

29'93

29-96

38

30

—

■26 N

2!J-96

2990

43

30

—

27 N

2997

29-90

39

33

—

23

28S W

3005

2997

42

34

—

10

29

N

2997

29-94

45

34

•40

3050

29-05

54

24

0-85

231

The observations in each line of the table apply to a period of twenty-four hours,
beginning at i) A. M. on the day indicated in the first column. A dash denote* that
the result is included in the next following observation.

320 Mr. Howard's Meteorological Journal. [April, 1824.

REMARK*.

Second Month.— 1. Clear morning with white frost : fine day. 2. Very fine day.
3. Hoar frost: foggy. 4. Cloudy. 5. Fine: lunar halo at ni^ln. 6. Ditto.
7. Drizzling. 8. Overcast. 9, 10. Drizzly. 11. Very tine morning. 12. Drizzly.
13. Morning fine: afternoon rainy: night stormy. 14. Cloudy. 15 — 17. Fine.
1 8. Cloudy and fine : a little snow in the morning between five and six, which melted
immediately. 19. Fine. 20. Drizzly morning: rainy evening. 21. Drizzly: very
foggy night. 22. Foggy morning : fine afternoon. 23. Bleak. 24, 25. Fine.
26. Bleak: some hail ami snow at three, p.m. 27. Rainy: some hail at half-past
eight, a. m. 28. Cloudy : rainy evening. 29. Cloudy.

RESULTS.

Winds : N, 4 ; E, 8 ; SW, 5 ; SE, 2 ; W, 5 ; NW, 8 ; NE, 3 ; Var. 1.

Barometer : Mean height

For the month 29-963 inches..

For the lunar period, ending the 20th 29-929

For 14 days, ending the 2d (moon south) . . . 29-938

For 13 days, ending the 15th (moon north) 30'026

Thermometer : Mean height

For the month 39-051°

For the lunar period 40-017

For days, the sun in Aquarius. 40-216

Evaporation 0-85 in.

Rain 2-31

Laboratory, Stratford, Tliird Month, 24, 1824. R. HOWARD.

ANNALS

OF

PHILOSOPHY

r

MAY, 1824.

Article I.

Remarks on Solar Light and Heat. By Baden Powell, MA. of
Oriel College, Oxford.

(To the Editor of the Annals of Philosophy.)

SIR, April 2, 1824.

In explanation of the design of the present communication, I
conceive it necessary to observe in the first instance, that having
been engaged in experiments on solar light and heat, I have laid
accounts of some of them before the Royal Society (see reports
of Royal Society, Annals, Feb. 1824) : those accounts, however,
being confined to the mere detail of the experiments, I wish
through the medium of your journal to offer some remarks on
the subject, of a more general nature, and which may be consi-
dered as forming a sort of introduction to such experimental
researches.

If then in taking a brief review of the present state of our
knowledge upon this subject, my remarks and statements should
not be of a nature wholly new, my design as thus explained will
be a sufficient excuse ; and the more so as I could not proceed
to the few experiments here given without such preliminary
considerations. I am, Sir, your obedient servant,

B. Powell.

I. (1.) Speaking according to our ordinary sensations, we are
accustomed to say that the sun communicates both light and
New Saks, vol. vii. y

322 Mr. Powell on Solar Light and Heat. [May,

heat. Light is transmitted in a way which we term radiation.
The heat from non-luminous hot bodies is transmitted to a dist-
ance in a way closely analogous ; and to which the same name
has been applied. In the first instance we might suppose that
the sun sends out two separate emanations, one of light, and
another distinct from it, and similar to that of radiant heat from
a mass of hot water ; and this, perhaps, was the first view taken
of the subject, though a confused idea of some very close and
intimate connexion subsisting between the solar light and heat
appears to have prevailed.

(2.) This subject, as might naturally be expected, attracted
the early notice of experimenters. A very slight examination
sufficed to show that the rays of solar heat (whatever their
nature might be) differed essentially in many properties from
those of terrestrial heat, whether radiated from luminous or non-
luminous bodies. Whether there existed a separate set of
heating rays distinct from those of light, and at the same time
differing in many respects from rays of terrestrial heat; or
whether these differences depended on some unknown property
of the rays of light, was a question which for a long time
remained without any direct investigation, and on which even
now, we have, perhaps, no very precise ideas.

Among the earliest experiments on the subject, if not actually
the first, were those of Mr. Boyle, on the different degrees of
heat communicated by the sun to black, white, and red-coloured
surfaces. These were extended and confirmed in the well-
known investigations of Dr. Franklin, &c.

" Mr. Boyle caused a large block of black marble to be
ground into the form of a spherical concave speculum, and found
that the sun's rays reflected from it were far from being too
powerful for his eyes, as would have been the case had it been
of any other colour; and although its size was considerable, yet
he could not set a piece of wood on fire with it; whereas a far
less speculum of the same form, made out of a more reflecting
substance, would presently have made it flame." — (Boyle on
Colours, 8cc.)

Scheele conceived that the sun's rays of light produced heat,
not when in motion, but only when stopped by the interposition of
solid bodies. — (Treatise on Air and Fire, &c.)

Mr. Melville seems to have viewed the matter nearly in the
same light, and to have conceived reflexion at an opaque surface,
the cause of excitation of heat from the sun's rays. — (See Phil.
Mag. June, 1815, a paper by Dr. Evans.)

(3.) In later times the experiments of Prof. Leslie, Sir H.
Davy, 8cc. have sufficiently established the property possessed
by that emanation (whatever its nature may be, whether simple
or compound) which is derived from the sun, of producing
greater heat in bodies in proportion as their surfaces owing to
darkness of colour, have the capacity of absorbing rays of light.

1824.] Mr. Powell on Solar Light and Heat. 323

It has been equally well established by Prof. Leslie, Count
Rumford, &c. that the heat emanating from a mass of non-
luminous hot matter, has no such relation to the colour, though
a very close one to the nature and texture of the surface.

(4.) The experiments of Sir E. Home (Phil. Trans. 1821,
Part I.) are particularly deserving of attention, as exhibiting
what might at first sight be considered an exception to the
above remarks; a greater effect being produced in some instances
on a white than on a black surface. A more attentive examina-
tion, however, will show us that these experiments prove thus
much. The heat occasioned by the rays of the sun when
received directly, or when in some degree intercepted as by thin
white cloth, on the skin, is greater than that communicated by
conduction to the same skin, through a black cloth in contact
with it, which is itself, in the first instance, heated by absorbing
the rays.

A white skin is scorched, and a negro's skin is not, in ten
minutes by the direct rays of the sun ; that is, as before, the
outer coat of the white skin allows some of the direct rays to
pass through and affect the sentient substance beneath ;
whereas in the case of the black skin, the rays are absorbed by
the black surface, and so affect the sentient parts only as heat
of temperature.

II. (5.) As to the nature of this heating effect, the greatest
difference of opinion has long prevailed among the most distin-
guished philosophers ; one party maintaining the totally distinct
existence of light and radiant heat in the compound solar beam;
the other contending for the absolute identity of the two : the
same principle being merely displayed under two different modi-
fications. (See Sir W. Herschel, Phil. Trans. 1800, Part II. ;
Leslie on Heat, p. 162, Biot, Traite de Physique, vol. iv. p.
690, &c.)

Without entering upon an examination of the merits of either
theory, we may proceed to remark that the first object in the
inductive examination of this subject is to ascertain distinctly
what peculiar properties of this heating emanation we can fix
upon by which its nature may be defined, and by the help of
which we may be enabled to compare it with other heating
emanations.

(6.) Among the most obvious properties of the solar rays, we
perceive that before adverted to, viz. that they produce heat on
bodies in proportion to the darkness of their colour, and not in
regard to the absorptive qualities of the texture of their surfaces
for the heat from non-luminous bodies. This relation is univer-
sal, and without any exceptions: it is consequently one which
we can satisfactorily adopt as the foundation of a distinctive
description.

(7.) We may from this advance to another test, which will
afford an additional characteristic. It has been distinctly shown

324 Mr. Powell on Solar Light and Heat. [May,

that all heating emanations from terrestrial bodies whether lumi-
nous or not, are more or less stopped, or even in some cases
totally intercepted, by the interposition of a glass screen. Similar
experiments may easily be tried on the solar rays.

That little or no diminution of effect is produced on a black-
ened thermometer exposed to the sun, by the interposition of
glass, has been shown by several experiments. As it is
remarked by De la Roche (Biot, Traite de Phys. vol. iv. p. 61 1),
I have also frequently observed the same thing, taking notice of
the temperature of the glass, as will be subsequently seen. But
there is another part of the question which still appears to me to
want further examination. The sun's rays produce some heating
effect on surfaces of a light colour. I have, therefore, tried
whether also in this case, and when the texture of the surface
was very absorptive for simple radiant heat, a glass screen has
any power to diminish the effect. Two thermometers were
exposed together to the direct and screened rays, one having its
bulb coated with indian ink ; the other with a thin paste of chalk
and water; the bulbs were free from contact. If there existed
in the solar beam any rays of such a nature that they were
affected by the texture rather than the colour of surfaces, and
were not capable of passing through glass, they would be affected
by a surface of chalk more than one of indian ink. If they
formed only a small proportion of the whole, the diminution,
when glass was interposed before the inked thermometer, might
be so small as to be imperceptible ; but with the whitened sur-
face, it would be much more conspicuous.

(8.) The following are the results of two sets of experiments
conducted on this principle :

r
Exp

Thermometers.

ned.

Temp, of glass.

)sed.

Scree

Thickness

A.

B.

A.

B.

Before

After

of glass.

Rise in two

White.

Black.

White.

Black.

exper.

exper.

Inch.

tigrade.

4-0°

6 5°

5-0°

9-0°

18-0°

19-0°

0-44

40

5-5

4*0

7-0

20-5

20-5

—

4-5

7-0

3-5

6-5

2 10

210

—

5-5

8-0

4-5

7-5

17-0

17-5

—

5-0

9-0

2-5

3-5

—

—

3-5

70

60

8-5

__

—

1-5

SO

3 •5

7-0

1S-5

19-0

0-06

Mean

4-0

6-57

4-14

7-0

1824.]

Mr

Powell on Solar Light and Heat.

325

Thermometers.

Rise in two
minutes cen-
tigrade.

Mean

Exposed.

1

Scree

B.

A.

B.

White.

Black.

White.

4-5°

7

5-0

325

6

4-0

5-0

10

50

4-0

7

325

4-18

7-5

431

A.

Black.

7

6

10

7

7-5

Temp.

Df glass.

Before

After

exper.

exper.

18

20-0

20

20-5

19

19-0

19

19-0

Thickness
of glass.

Inch.

0-06
0-44

(9.) These results exhibit a very close agreement in the ratio
of the risings of the two thermometers, when exposed, and when
screened, and this with glasses of different thickness, at different
times, and with different absolute intensities of the sun's rays ;
as also when the colours of the bulbs were mutually changed.
The mass of the bulb A was somewhat greater than B ; the glass
acquired no heat sufficient to interfere with the results ; and the
thermometer was always placed so that the bulbs were not near
any object which might radiate heat. The temperature of the
air affecting both surfaces equally would tend to diminish the
ratio. To its variation, I conceive, the trifling difference in the
ratios may fairly be ascribed.

(10.) Hence, I think, we are entitled to conclude, that there
do not exist in the solar beam in its natural state any rays of the
description just alluded to ; but that the whole emanation
consists of one sort of rays distinguished by the two characteris-
tics of affecting substances with heat in proportion to the dark-
ness of their colour, and being wholly transmissible through glass
without heating it ; and that these same rays when they infringe
on the eye are capable of producing the sensation of vision ;
and by the absorption of some, and the reflexion of others, of
their constituent parts, at the surfaces of bodies, produce the
phenomena of colours.

(11.) The heating effect maintains an intimate relation to
light both in respect to the substances which it traverses without
interception, and to those by which it is absorbed, and to the
degree of absorption. It is found to accompany the rays of
light in the most constant and inseparable manner : through
whatever substance, and in whatever direction it takes its course,
this is strikingly exemplified in one of Sir W. IlerschePs experi-
ments (Phil. Trans. 1800, No. 13, Exper. 11), m which the heat-
ing effect is shown to accompany the rays of light in all the
alterations of its course through a Newtonian telescope with
four lenses.

Speaking in general terms, within ordinary limits, and for
light of the same colour, we may say, that the healing effect
increases or decreases in proportion to the intensity of illuminat-

326 Mr. Powell on Solar Light and Heat. [May,

ing effect. Prof. Leslie considers the proportion to be precise
and undeviating.

(12.) Whatever we suppose to be the state in which the heat
exists when it thus inseparably accompanies the luminous rays,
it is evident that there must be some peculiar circumstance in
the mode of its union which makes its effects sensible only under
some particular circumstances ; and under others endows it with
properties which heat in its simple radiant state does not possess.
It evidently exists in a state essentially different from that of
simple radiant heat :, and we may in general say, that it is never
developed or rendered sensible except under such circumstances
as produce at the same time some modification or change in the
light itself.

Upon considering all these well established facts, I think,
instead of using such terms as " calorific rays," and " luminous
rays," it is much more conformable to facts, and involves no
hypothetical ideas, to describe the phenomena by the terms
" rays of light," and the " heating poioer or property " of those
rays".

III. (13.) Thus far my remarks have been confined to the
nature of the heating power of the sun when its rays are in that
state in which they naturally are, as coming directly from that
luminary. In the next place we have to inquire whether by any
modification which these rays may be made to undergo by artifi-
cial means, we can attain to any further elucidation of the nature
of this heating power.

(14.) It has been shown by the experiments of M. Berard
(Biot, Traite de Phys. vol. iv. p. 603, &c), that when light under-
goes polarization, the heating power participates in that effect.

It has also been shown by the same distinguished philosopher
(see Biot as above), that simple radiant heat when unaccompa-
nied by light is susceptible of being polarized also. In consi-
dering these results, we must be careful not to confound them
together ; because simple rays of heat are capable of displaying
the effects of polarization, and the heating effect in the solar
beam also obeys the same impulse, we must not hastily conclude
that the same agent existing in the same form is, therefore, the
common heating principle in both cases.

(15.) The heating power of the sun is well known to be
capable of being collected in a focus along with the luminous
rays, both by reflexion and refraction. By the former means
simple radiant heat may also be concentrated : this circumstance
again shows a similarity, but does not prove an identity in the
agents or powers.

In one of Sir W. Herschel's experiments (Phil. Trans. 1800,
IS T o. 15, Exper. 23), a focus of heat different from that of light
seems to be proved. This opinion it is not my design at pre-
sent either to maintain or controvert. I have only to observe,
that granting its truth, it must not be applied as an argument to

1824.] Mr. Powell on Solar Light and Heat. 327

show that simple radiant heat exists distinctly in the solar beam;
or in other words, that the sun's heat is produced by an assent
identical with that which emanates from non-luminous hot bo-
dies ; it merely shows that the refractive and dispersive power
which the lens exercises on light is capable of eliciting from it a
certain agent or set of rays which produces the sensation of heat,
but not that of illumination ; and by no means shows that that
agent exists in a separate form when the rays of light are in
their direct natural condition.

If the focus of heat be the same as that of light, and the expe-
riment of Sir W. Herschel (Phil. Trans. 1800, No. 15, Exper.
19, 20) be admitted, where the concentration of simple radiant
heat by a lens appears to be proved, the same remark applies as
that just made with respect to concentration by a mirror.

(16.) The principal modification which the sun's rays are
made to undergo, and from which conclusions relative to the
nature of their heating power have been drawn, is the analysis
to which they may be subjected by the prism. Into any discus-
sion upon the controverted points respecting these experiments,
I shall abstain from entering. We will suppose it granted that
a set of invisible heating rays are separated beyond the visible
red rays. The existence of such rays in a distinct state in the
spectrum cannot be considered as any proof that they have that
distinct existence in the natural state of the rays. It by no
means proves that any such simple heating rays must have come
directly from the sun, and have been transmitted through the
prism, with merely a change in their direction.

From the experiments above given, we may, in reference to
this point learn thus much : the direct rays are not accompanied
by any separate heating rays which are either stopped by glass,
or bear a relation to texture more than colour. It therefore
becomes an important object to try whether in the prismatic
beam these heating rays possess those characteristics or not.
With respect to one of the characteristics, viz. transmissibility
through glass, we have no ground to assume that the heating
prismatic rays possess it from the circumstance of their passing
through the prism, because, when the light impinges upon the
prism, we know that it has not any such separate rays accompa-
nying it ; and of the nature or properties of the rays during their
passage through the prism, we are altogether ignorant.

(17.) My object in making these remarks is merely to attain
if possible some clear ideas on the subject in question ; and to
point out those parts of it which appear to me to want further
elucidation ; and to several of which I have attempted to direct
experimental research. The subject must always remain
perplexed and obscure so long as we dispute about such terms
as " calorific rays," " luminous," or " non-luminous heat," &c.
The only way of arriving at clearness of ideas, and thence being
able to pursue the inquiry in a satisfactory manner, is to fix upon

328 Col. Beaufoy's Astronomical Observations. [May,

some definite criteria by which the nature of heating agents may
be distinguished and compared ; and instead of framing theories
to explain the union of heat and light in the sun's beams, to
describe the nature of the phenomena in conformity to the
criteria above pointed out, as afforded by certain experimental
facts.

It becomes necessary to subject to an examination by those
criteria the supposed exterior heating effect of the prismatic
spectrum ; as well as the analogous exterior heat of the cone of
light formed by a lens, and probably several other phenomena,
before we can obtain from them any further information respect-
ing the nature of the heating power which is so inseparably
associated with the sun's light.

The remarks hitherto made apply to the subject of solar light
and heat; but they might be extended also to the investigation
of the relations of light and heat from terrestrial sources. The
want of some fixed criteria of definition must upon consideration
be felt equally in following up this part of the subject as in the
former ; and to endeavour to supply that want should be the
first business of the experimenter.

Some further observations will probably form the subject of a
future communication.

Article II.

Astronomical Observations, 1824.
By Col. Beaufoy, FRS.

Bushey Heath, near Stanmore.

Latitude 51° 37' 44-3" North. Longitude AVest in time 1' 20'93".

March 28. Emersion of Jupiter's second < 8h 17' 24" Mean Time at Bushey.

satellite J 8 IS 45 Mean Time at Greenwich.

March 31. Emersion of Jupiter's first < 8 13 49 Mean Time at Bushey.

satellite } 8 15 10 Mean Time at Greenwich.

"12 15 44 Immersion of a small star.

12 19 01 Im. Jupiter's 4th satellite.

12 21 19 Immersion of a small star.

13 21 51 Em. Jupiter's 1st limb.
J3 22 01 Em. Jupiter's 2d limb.

Clouds prevented the Immersion of Jupiter being seen: at the Emersion, the limbs of
Jupiter, and the Moon, were tremulous.

April 7. Emersion of Jupiter's first ( 10 09 15 Mean Time at Bushey.

satellite }\0 10 36 Mean Time at Greenwich.

April 5. Occultations by the moon, Si-
derial Time

1824.] On the Decomposition of the Metallic Sulphates. 329

Article III.

On the Decomposition of the Metallic Sulphates by Hydrogen
Gas. By J. A. Arfwedson.

Since it has become known that the fixed alkaline sulphates
may, by means of hydrogen gas, be reduced to metallic sulphu-
rets, it was natural to infer that the same method would be
equally successful with the different metallic sulphates. This
consideration induced me to undertake a set of experiments by
the above-mentioned method, in order to determine more accu-
rately the nature of the combination of sulphur and manganese;
concerning which chemists have been long of opinion that the
manganese in it is in the state of an oxide ; although several
circumstances, the most important of which is its property to
dissolve in acids with the evolution of sulphuretted hydrogen
gas, have led also to the opposite sentiment. The experiments
which I am going to relate had at first no other object than to
determine the nature of this compound of sulphur and manga-
nese ; but the unexpected results obtained led afterwards to the
experiments which will be related.

To avoid unnecessary prolixity in the description of the follow-
ing experiments, I should state in the first place, that all the
reductions of which I shall have occasion to speak, were per-
formed in precisely the same kind of apparatus, consisting
merely of a piece of barometer tube, of rather difficultly fusible
glass, about the middle of which was blown a small globular
cavity, into which the substance destined for reduction was put.
The hydrogen gas was prepared from zinc and dilute sulphuric
acid. It was dried by passing it through fused muriate of lime,
before it entered the tube. In those cases where sulphuretted
hydrogen gas was employed, it was freed from the accompany-
ing moisture in exactly the same way.

Reduction of Protosulphate of Manganese by Hydrogen Gas.

Tn the little apparatus just described a portion of pure sulphate
of manganese was put, which, though previously deprived of its
water, was again heated in the apparatus till I was certain that
it retained no moisture : then the evolution of hydrogen gas was
set a-going, and when the whole atmospherical air had been
driven out of the apparatus, the salt was heated over an Argand
spirit-lamp. Till the matter became red-hot, it underwent no
alteration ; but at that temperature the salt began to become
dark, and at the same time sulphurous acid and water came
over together. When this extrication was at an end, and when
the hydrogen gas passed through unaltered, the reduction was

330 M. Affwedson on the Decomposition of [May,

considered as completed, and the apparatus was allowed to cool,
still filled with hydrogen gas. The product of this experiment
was a light- green powder, which dissolved in muriatic acid, with
the evolution of sulphuretted hydrogen gas ; and the solution
was rendered only slightly turbid by the solution of barytes.
Thus it appears that the salt was completely decomposed :
1*484 gramme of sulphate of manganese thus treated lost 0*697
gr. in weight, or 46*97 per cent. In another experiment 0*553
gr. lost 0*263, or 47*56 per cent. x\ third experiment gave a
loss of 1*034 gr. from 2*195 grs. of salt, which amounts to 47*10
per cent. The mean of these three experiments gives 47*22 for
the loss of weight sustained by 100 parts of anhydrous sulphate
of manganese when thus treated.

It becomes now a question of some difficulty to determine
the composition of the substance thus obtained. It is impossible
that it could contain the same quantity of sulphur as the salt
employed (Mn S a ), because a quantity of sulphurous acid had
made its escape : nor could it be manganese combined with an
atom of sulphur (Mn S) ; for on such a supposition the weight
lost by 100 parts of the salt should have been 52*32, which was
considerably greater than that found by experiment. I thought
it, therefore, likely that I had obtained a body analogous to the
crocus antimonii ; or that it consisted of a combination of sul-
phuret of manganese and protoxide of manganese. The simplest
proportion in which such a combination can take place, is one
atom of sulphuret with an atom of protoxide ; and in order to
obtain such a result from protosulphate of manganese it is
obvious that 100 parts of the salt must lose 47*09 ; or almost the

loss sustained in the preceding experiments ; for 2 Mn S- :

2 Mn & - (Mn -f- Mn S 2 ) :: 100 : 47*09. The reason of this

combination may be thus explained, that the sulphate of manga-
nese is decomposed by hydrogen gas in such a way that half of
the salt is changed into Mn S 2 , while the other half loses its
acid and remains in the state of protoxide. In order to prove
the truth of this opinion, it was merely necessary to determine
the quantity of sulphur in the reduced body, the quantity of
manganese being already known from our knowledge of the
composition of the salt ; and the remainder wanting to make out
the complete weight must obviously be oxygen. I attempted
first to determine the sulphur by dissolving the body in aqua
regia in order to oxidize the sulphur, that it might be afterwards
thrown down by barytes ; but the evolution of sulphuretted
hydrogen gas which took place on the addition of the acid
rendered this method abortive. I next dissolved the matter in
muriatic acid, and made the sulphuretted hydrogen gas pass
through a solution of acetate of lead ; but even when this pro-
cess was followed, I obtained an uncertain and varying product :

1824.] the Metallic Sulphates by Hydrogen Gas. 331

the cause of which was that the sulphuret of lead formed is partly
converted into sulphate during the drying.

Still, however, the method remained of determining the quan-
tity of sulphur by roasting the compound. A portion of the
substance in question prepared just before, which I shall here-
after call oxisulphuret of manganese, was heated to redness in a
platinum vessel. The matter took fire before it became red-hot
and burnt, leaving behind brown oxide of manganese, or oxidum
manganoso-manga)iicuin. But in order to drive off the whole of
the sulphur, a long continued roasting was necessary.

0*36 gr. of oxisulphuret gave by this treatment 0-347 gr. of
brown oxide of manganese ; equivalent to 9639 per cent. The
oxide of manganese thus obtained dissolved in muriatic acid
without any residue, and the solution was not rendered turbid
by muriate of barytes. Now if the oxisulphuret of manganese

were a compound of Mn + Mn S : , then 100 parts of it would

correspond with 96*58 parts of Mn + Mn : , or brown oxide of

manganese ; and the result, as is obvious, corresponds very well
with this calculation.

Meanwhile, in order to be certain of the accuracy of these
conclusions, I thought it necessary to make direct experiments,
in order to show the existence of protoxide of manganese in
body.

For this purpose a portion of protosulphate of manganese
was reduced bv hvdrogen eras, in the way above described.
After this the apparatus was weighed in order to determine the
amount of the oxisulphuret remaining.* A stream of dry
sulphuretted hydrogen gas was then passed through the same
apparatus. It was clear that the protoxide of manganese, in
case it was present, would by this process be converted into
Mn S J ; consequently a certain portion of water would be
formed. This accordingly took place, and with so much rapi-
dity, that almost as soon as the gas entered the apparatus, and
before any heat had been applied, the whole interior of the small
glass globe in which the matter lay, was covered with small drops
of water. It is possible that the reduction in this case might be
accomplished without the application of any heat; but to make
sure of the reduction, it is expedient to apply the heat of a spirit-
lamp till the matter becomes of a low red heat ; and the process
must be continued as long as any moisture makes its appear-
ance. The apparatus is then to be allowed to cool. It is to be
wf i'jhed after the gas with which it is filled has been driven off,
and replaced by common air. 0*933 gr. oxisulphuret treated in
this way left 1*022 gr. of sulphuret. This corresponds to 100
parts of the former, and I09-.34 of the latter. This is just the

* The diminution of weight was cjuitc the same as in the former experiment.

332 M. Arfwedson on the Decomposition of [May,

quantity of Mn S 2 which, according to calculation, should be

obtained from 100 parts of Mn + Mn S 2 ; for Mn + Mn S- :
2 Mn S 2 : : 100 : 109-98.

The colour of oxisulphuret of manganese is somewhat a lighter
green than that of the protoxide. It remains unaltered though
exposed to the air; and thus is easily distinguished from the
protoxide, which, as is known, speedily absorbs oxygen, and
becomes brown. It is easily distinguishable likewise from the
sulphuret of manganese, which has a much darker green colour,
and which moreover, when long exposed to the air, gradually
becomes oxidized, and assumes a brown colour.

The constituents of 100 parts of oxisulphuret of manganese
calculated from the data given above, are as follows :

Manganese 70*26

Sulphur 19-86

Oxygen 9-88

100-00
Or,

Sulphuret of manganese 55

Protoxide of manganese 45

100

Reduction of Protoxide of Manganese by Sulphuretted Hydrogen

Gas.

It was of importance after the preceding experiments to deter-
mine whether any other sulphuret besides Mn S' 2 could be formed
when protoxide of manganese is treated with sulphuretted
hydrogen gas. I prepared, therefore, a portion of protoxide of
manganese by reducing the oxide by means of hydrogen gas,
and after the weight of the protoxide had been determined with
the requisite precision, it was treated with sulphuretted hydrogen
gas so long as any water was formed. From 0-317 gr. protoxide
of manganese treated in this way, I obtained 0-392 gr. sulphuret
of manganese, or from 100 parts of the former 123*66 of the

latter; but Mn : Mn S 2 : : 100 : 122-19. The small excess in
the experimental result proceeded doubtless from this cause,
that the protoxide could not be weighed with sufficient rapidity
to prevent it from absorbing a little oxygen from the air.

I attempted afterwards to reduce protosulphate of manganese
by means of sulphuretted hydrogen gas. 0-899 of anhydrous

salt gave 0*526 of sulphuret of manganese. "Now Mn S j :
Mn S 9 : : 0-899 : 0-523. From this it .seems to appear that
manganese in the dry way cannot combine with more than two
atoms of sulphur.

1824.] the Metallic Sulphates by Hydrogen Gas. 333

Examination of the Substance formed when Protocarbonate of
Manganese is fused in a close Vessel with Sulphur.

1 . Protocarbonate of manganese was intimately mixed with
nearly twice its weight of washed flowers of sulphur. The mix-
ture was put into a small retort blown at the enameller's lamp,
which was afterwards slowly raised to a red heat. When no
more sulphurous acid was exhaled, and when the superfluous
sulphur had been volatilized and collected in the beak of the
retort, the mouth of the retort was stopped with a cork, and the
fire withdrawn. On cooling, the matter contained in the belly
of the vessel was taken out. It had the light-green colour of
oxisulphuret of manganese. It dissolved in muriatic acid with
the evolution of sulphuretted hydrogen gas ; but the solution
was considerably affected by muriate of barytes. 0418gr. of it
left after burning 0-392 gr. of brown oxide of manganese.
Another portion, weighing 0*710 gr. was dissolved in muriatic
acid, and precipitated by muriate of barytes. There were
obtained 0-039 gr. of sulphate of barytes, equivalent to 0-026
protosulphate of manganese ; consequently the abovementioned
0-418 gr. of sulphuretted manganese contained 0-015 protosul-
phate of manganese, and the remaining 0*403 had given 0*377
of brown oxide.* 0-403 Mn + Mn S 2 would have given 0*388
brown oxide, and the same quantity of Mn S- is proportional to
0-354 brown oxide ; consequently the body under examination

seems to be a mixture of Mn S- with a smaller quantity of Mn

than in the compound Mn -f- Mn S' J .

2. It was probable that the imperfect conversion of the proto-
carbonate of" manganese into Mn S a in this experiment, was
owing to the process having been conducted too rapidly; so
that the sulphur was distilled away before it had time to decom-
pose all the Mn. A new portion of protocarbonate of manga-
nese and sulphur was, therefore, mixed together, and exposed to
a heat just sufficient to keep the sulphur in the state of fusion.
When in consequence of continuing this heat for several hours
it was supposed that the decomposition might be completed, the
heat was augmented so as to drive off the excess of sulphur, and
the retort was corked and allowed to cool. In the same manner
as in the former experiment, it was found that 0-922 gr. of the
sulphuret of manganese now formed contained 0-036 of proto-
sulphate of manganese. The remaining - 886 left when burnt
0'787 of brown oxide of manganese. 0*886 Mn S' J are propor-
tional to 0*778 brown .oxide of manganese. Hence it appears

* Tliis is agreeable to an observation already made, that no protosulphate of manga-
new in formed when sulphuretted msnganeie is burnt.

334 M. Arfwed$on on the Decoinposition of [May,

that in the latter experiment the sulphuret contained a smaller
admixture of oxide than in the former.

3. A portion of the sulphuret of manganese prepared in the
second experiment was accurately mixed and fused with its
own weight of sulphur. 0-732 gr. of this product contained
0*031 of protosulphate of manganese, and 0-701 gr. of the
remaining quantity gave when burnt 0-619 gr. of brown oxide of
manganese. This quantity differs only by 0*004 gr. from the
calculated quantity of oxide which should have been obtained
from 0*701 Mn S s ; so that the sulphuret of manganese of this
experiment appears to have been free from protoxide.

From these experiments it appears that when protocarbonate
of manganese is fused with sulphur in a close vessel, there is
always formed (together with a little protosulphate of manga-
nese) a sulphuret of manganese containing more or less oxide.
This is the substance which has been erroneously denominated
sulphuretted oxide of manganese ; and the best way to obtain a
sulphuret free from oxide is to fuse this substance a second time
with its own weight of sulphur.

Native Sulphvret of Manganese, or Manganglanse, from
Nagyag, in Transylvania.

In connexion with the preceding experiments, it seems of
importance to determine the constitution of sulphuretted man-
ganese prepared by nature. This mineral, according to the
analysis of Klaproth, is composed of

Protoxide of manganese 82

Sulphur 11

Carbonic acid 5

98*

Klaproth concluded that the manganese was in the state of
protoxide, because he found that when protoxide of manganese
and sulphur were melted together, he obtained a compound similar
to the natural one as far as external characters were concerned.
But the insufficiency of such a reason, connected with the cir-
cumstance that the mineral, like the artificial sulphuret of manga-
nese, dissolves in acids with the evolution of sulphuretted
hydrogen gas, seems to furnish sufficient ground for suspecting
the accuracy of Klaproth's opinion.

0*494 gr. of pulverized manganglanse were heated to redness
on a thin platinum plate, till they ceased to lose any more
weight. Native sulphuret of manganese parts more difficultly
with its sulphur than what is artificially prepared. On that
account the roasting must be several times repeated, because
the weight is diminished each time the process is repeated. The

* Beitrage, iii. 42.

1824.] the Metallic Sulphates by Hydrogen Gas. 335

residual oxidum manganoso-manganicum weighed 0*425 gr. It
dissolved completely in muriatic acid, and the solution was not
rendered turbid by muriate of barytes, and was found to contain
no foreign body, except a trace of iron. 0494 Mn S 2 are pro-
portional with 0434 Mn -f 2 Mn ; which does not much exceed
the experimental result. We may conclude from this experi-
ment that manganglanse is a compound of one atom manganese
with two atoms sulphur. That the loss of weight was a little
greater than it ought to have been was a necessary consequence
of the protocarbonate of manganese mixed with the ore, which
could not be completely separated, notwithstanding every possi-
ble care. Even when we rind pieces which appear quite pure,
if we heat them in a little glass capsule, they always become
spotted with small brown flocks of decomposed carbonate.
These may always be easily perceived if we examine the matter
through a glass.

Reduction of Sulphate of Zinc by Hydrogen Gas.

The zinc vitriol employed in these experiments was prepared
by dissolving pure oxide of zinc in distilled sulphuric acid. The
salt was moderately heated to render it anhydrous without
driving off any of the acid. It was then treated with hydrogen
gas exactly in the same way as the protosulphate of manganese.
At the same temperature in which that salt was reduced, the
sulphate of zinc began likewise to be decomposed ; sulphurous
acid and water were given out ; and in a short time the reduc-
tion was completed. A little before that period, the matter
swelled up and acquired a motion ; at the same time its temper-
ature augmented, in consequence of which a small portion of
metallic zinc was sublimed, and attached itself to the upper part
of the apparatus.

The reduced substance was pulverulent and straw-yellow.
When treated with sulphuretted hydrogen gas a considerable
portion of water was formed. It dissolved in muriatic acid with
the evolution of sulphuretted hydrogen gas, and the solution was
not rendered turbid by muriate of barytes. Hence it was
evidently a mixture of sulphuret and oxide of zinc.

The loss of weight during the reduction of the salt was in three
careful experiments as follows : In one experiment 0*544 gr. of
zinc vitriol left 0*305 gr. or 56*07 per cent. In the next 2*933
gr. of the salt left 1*708, or 58*23 percent; and in the third
1*106 gr. of salt left 0*664, or 56*95 percent.

The quantity of oxisulphuret here obtained is greater than it
ought to be if the compound were analogous to the oxisulphuret

of manganese ; that is to say, Zn + Zn S- *, for 100 parts of

sulphate of zinc correspond by calculation with 52*52 Zn + Zn
S 9 , a quantity which deviates considerably from that actually

336 M. Arfioedson on the Decomposition of [May,

obtained ; and an equally great, if not a greater deviation would
result if we suppose that the oxide and sulphuret are combined
in other atomic proportions. It was observed that a portion of
the zinc was reduced to the metallic state ; but the quantity
was so small that the amount of the change which it would
produce cannot come into calculation. Indeed if it were to
produce any change upon the result, the obvious consequence
would be to render the loss of weight a little too high ; whereas
in all the experiments that loss was too small. From the expe-
riment it is obvious, that the loss of weight is various in different
experiments, and that it becomes less when the quantity of salt
operated on is greater.

These circumstances taken together might naturally lead to
the opinion that the sulphate of zinc was more or less completely
decomposed in the different processes. But as has been already
stated, a portion of the reduced mass was always dissolved in
muriatic acid, and tested with muriate of barytes, by which the
liquid was sometimes rendered slightly opalescent, but not the
least precipitate ever fell. There might, however, have been
some circumstance which occasioned the result to come out in-
accurate, but in what it consisted I cannot say.

Meanwhile we may conclude from the preceding experiments,
that when sulphate of zinc is treated with hydrogen geus, the salt
is decomposed in such a way that somewhat more than the half
of it becomes sulphuret, and the remainder oxide of zinc ;
though at the same time the proportions of each of these bodies
do not correspond with any atomic numbers ; and experiments
which do not give corresponding results, are not worth the pains
of determining the relative proportions of the constituents
obtained.

Examination of Native Sulphuret of Zinc, or Zinc-Blende.

I employed for this analysis a portion of a large piece of crys-
tallized yellow transparent blende, as the purest variety of that
mineral met with in nature.

a.- 1*758 gr. of pulverized blende were digested with an aqua
regia, which had been previously gently wanned, so that it began
to give out chlorine gas.* When the residual mass, coagulated
into a lump, seemed to be no longer acted on by the acid, it was
separated and washed. Dried on the stove in a platinum dish,
it weighed 0-393 gr. Being heated to redness in a crucible
much sulphur was driven off, but a portion remained which was
sulphuret of zinc. It was dissolved in aqua regia, without any
residue, and the diluted boiling-hot solution was precipitated by

* I have found that this is the best solvent which can be employed ; for when we
dissolve blende in nitric acid or in an aqua regia in whicli no chlorine exists, as when a
dilute nitric acid is employed, there is always disengaged at first a little sulphuretted
hydrogen gas which may be made evident by holding a paper dipped in solution of lead
over the mouth of the vessel..

1824.] the Metallic Sulphates by Hydrogen Gas. 337

carbonate of potash. As soon as inconsequence of the conti-
nued application of heat, all excess of carbonic acid was driven
off. The precipitate was collected on the filter and washed.
After being heated to redness, there remained 0-146 gr. oxide
of zinc equivalent to 0*117 gr. of metallic zinc. The remainder
of the 0-393 gr. or 0*276, therefore, was sulphur.

b. The sulphuric acid formed by the first digestion in aqua
regia was precipitated by muriate of barytes. There were
obtained 2-288 grs. of sulphate of barytes, equivalent to 0-786
sulphuric acid, or 0-316 sulphur.

c. The residual liquid was mixed boiling-hot with carbonate
of potash, taking the necessary precautions that none of it was
lost in consequence of the effervescence . When no more car
bonic acid was disengaged, the carbonate of zinc was collected
on the filter and washed. When heated to redness, it left 1-311
gr. of zinc oxide, and, except a trace of iron, it did not appear
to contain any other substance in solution : 1-311 oxide is equi-
valent to 1-05 metallic zinc. Thus it appears that 1*758 blende
contain

Zinc a 0-117

b 1-050

1-167

Sulphur a 0-276

b 0-316

0-592

1-759
Or in 100 parts :

Zinc 66-34

Sulphur 33-66

100-00

This is two atoms of sulphur to one atom of zinc for Zn : 2 S
:: 66-34 : 33-09.

Sulphate of Cobalt.

1. 0-639 gramme of pure crystallized sulphate of cobalt ; but
previously freed from water by heat, were treated in the way
already described, with hydrogen gas. At a high temperature
the salt was easily and rapidly decomposed ; sulphurous acid and

piuly ue
water were formed ; and a dark grey cohering mass remained,
which weighed 0-345 gr. In a subsequent experiment, the
weight remaining from 0-772 gr. of the salt, was 0-412 gr. The
substance thus obtained dissolved in a great measure in muriatic
acid, without the extrication of any gas. When the mass was
heated, it was attacked a little more by the acid, and a little
sulphuretted hydrogen gas was disengaged. The undissolved
Netv Series, VOL. v II. z

338 M. Arfwedson on the Decomposition of [May,

residue when heated gave out sulphur, and oxide of cobalt
remained.

2. 0*379 gr. of this reduced substance, treated with sulphu-
retted hydrogen gas, gave out water, and the weight at the
conclusion of the process was 0*440 gr. In a subsequent expe-
riment the weight was increased from 0*224 to 0*261 gr. The
number 0*440 corresponds with 116*09 to the 100 parts, and
the number 0*261 with 117*04. The water obtained in this pro-
cess, together with what was said above of the presence of
sulphur, shows us that the sulphate of cobalt decomposed by
hydrogen gas becomes likewise an oxisulphuret.

The residue per cent, when the salt is reduced, amounts in the
first experiment to 53*99 ; and in the second to 53*24 ; or at a

medium to 53*62: but 2 Co & : Co + Co S' 2 :: 100 : 53*55.
From this we may conclude, that sulphate of cobalt is decom-
posed by hydrogen gas in the same way as protosulphate of
manganese ; or that one-half of the salt is converted into oxide,
and the other half into sulphuret. The experiments with sulphu-
retted hydrogen gas ought to have corresponded with the fore-
going result ; but this is not the case ; for the weight of Co +
Co S 2 : 2 Co S°- :: 100 : 109*7 ; consequently from 100 parts of
the oxisulphuret I should have obtained 109*7 of sulphuret,
whereas in the experiments I got as much as 117*04 ; but I have
good reasons for presuming that this experiment formed a sul-
phuret containing more sulphur than Co S a . Since the cobalt
pyrites from Riddarhyttan, according to Hisinger's analysis,*
consists of cobalt united to three atoms of sulphur. The number
1 17*04 agrees nearly with Co S 2 + Co S ; .

Sit/phate of Nickel.

A portion of pure oxalate of nickel (obtained according to
Laugier's method, by adding oxalic acid to a solution of nickel
not free from cobalt in ammonia) was heated in a small retort
till it was decomposed. The residual metallic nickel was
dissolved in dilute sulphuric acid, and evaporated till it yielded
crystals.

1*015 gr. of crystallized sulphate of nickel freed from moisture
by exposure to heat,i" were treated with hydrogen gas. This
salt was decomposed as easily a»d speedily as the preceding
salts. At first sulphurous acid and water were evolved, but at
last the gas which came over had the odour of sulphuretted
hydrogen. After an hour, even this odour ceased, and the
apparatus was allowed to cool. The residue of this experiment
weighed 0*49 gr. and was a pale-yellow cohering mass, which

« Afhandl. i Fysik, Keuii, &c. iii. 310.

•j- This must be done with caution, because the salt begins to be decomposed at a
cherry-red heat.

1824. J the Metallic Sulphates by Hydrogen Gas. 339

here and there seemed to have undergone a commencement of
fusion. It was brittle, and easily reduced to a powder, which,
when rubbed against a hard body, gave a whitish-yellow metallic
streak ; and was attracted rather strongly by the magnet. It
dissolved in nitric acid, leaving a residue of sulphur. By con-
centrated muriatic acid, it was slowly attacked, with the evolu-
tion of sulphuretted hydrogen gas ; but in dilute muriatic acid it
did not seem to dissolve even when the action of the acid was
assisted by heat.

The product of this experiment could not be an oxisulphuret,
because it is well known that the oxide of nickel is reduced to
the metallic state by hydrogen gas. I must have obtained a
sulphuret which contained less than two atoms of sulphur, as
the decomposition of the sulphate of nickel was attended with
the evolution of both sulphurous acid and sulphuretted hydrogen
gas. It is to be presumed that the salt lost one atom of sulphur,
so that the sulphuret of nickel obtained was a compound of one
atom of each of its elements. Let us see how this supposition
corresponds with the experiment. 1*015 gr. of sulphate of
nickel left a residue of 0*49 gr. This corresponds with 48-28

from the hundred parts ; but the weight of N i S? : N i S : : 100 :
48*44. From this it is evident that the sulphuret obtained was

Ni S. I ought to mention likewise that the reduction of the
sulphate of nickel should not take place in too high a tempera-
ture ; for in that case, the sulphuret of nickel melts into lumps,
in consequence of which an additional portion of sulphur is dissi-
pated, and the loss of weight turns out too high. 1 obtained in
an experiment made in this way from 1*095 sulphate of nickel a
residue of 0-513 ; yet according to the preceding calculation, it
ought to weigh 0.53. But I cannot with certainty affirm that
this additional loss of weight is owing merely to the escape of
sulphur; for at the time when the matter melts, if the gas which
escapes be set on fire, it burns with a distinct green flame.
From this it seems not unlikely that even some of the nickel flies
off as well as of the sulphur.

1 now wished to know in what respects this lower combination

of sulphur with nickel differed from Ni S-. A portion of this
second compound, therefore, was prepared by passing sulphuret-
ted hydrogen over red-hot oxide of nickel. 1*186 gr. ot nickel
oxide gave 1*438 gr. of sulphuret of nickel, which deviates very

little from the quantity Ni S', which ought by calculation to

have been obtained; for the weight of Ni : Ni S 2 :: 1*180 :
1*441. This combination of nickel and sulphur was pulverulent.
Its colour was a somewhat darker-grey than that ot the oxide.
It was not in the least attracted by the magnet. It could not be

z2

340 M. Arfwedson on the Decomposition of [May,

fused even when exposed to a higher temperature than was
necessary to fuse N l S. Thus the two sulphurets differ in several
respects from each other.

Analysis of native Sulphuret of Nickel, or the Mineral called

Hair Pyrites.

Klaproth, who analyzed this mineral, found it to consist of
metallic nickel mixed with a little cobalt and arsenic ; and this
conclusion was considered as correct till Prof. Berzelius, a few
years ago, in consequence of a set of experiments on it by the
blowpipe, concluded that hair pyrites was not metallic nickel,
but sulphuret of nickel ; but as no analysis of it, so far as I know,
has yet been made, I conceived that the undertaking should not
be neglected, especially as Prof. Berzelius had the goodness to
present me for the purpose with a very beautiful piece of that
rare mineral.

a. 0*222 gr. of needles of hair pyrites freed as much as possi-
ble from the small fragments of quartz with which they were
mixed, were digested in aqua regia, as long as any thing was
dissolved. The solution, together with a small portion of sul-
phur swimming upon the surface, was decanted off, the quartz
grains lying at the bottom of the flask. These grains, when
washed and heated to redness, weighed 0*006 gr. The undis-
solved sulphur was likewise separated. It weighed, after being
washed and dried, 0*002 gr.

h. The solution in aqua regia was precipitated by muriate of
barytes, and the sulphate of barytes obtained being collected on
the filter and edulcorated, weighed, after being heated to red-
ness, 0*524 gr. containing 0-18 sulphuric acid, or 0*072 sulphur.

c. The residual liquid was freed from barytes by sulphuric
acid, and then precipitated by caustic potash. The hydrate of
nickel containing potash was collected on a filter, and washed
with hot water, till the liquid which passed through ceased to
leave any residue when evaporated to dryness. It took several
days to accomplish this. Being then dried and heated to red-
ness, it was oxide of nickel, and weighed 0*176gr. equivalent to
0*139 gr. of metallic nickel.

A portion of this oxide of nickel was dissolved in muriatic
acid, and the solution was supersaturated with caustic ammonia.
By this means the precipitate which appeared at first was dis-
solved, with the exception of a few inconsiderable flocks, which
being examined before the blowpipe were found to be alumina
mixed with oxide of iron. These flocks without doubt owe their
origin to the stony matter accompanying the hair pyrites. From
the ammoniacal solution the oxide of nickel was precipitated
by caustic potash. The residual liquid was colourless, but when
it was evaporated to dryness, and again redissolved in water,
there remained a brown powder, which gave a blue glass with
borax, and consequently was oxide of cobalt ; but the quantity

1824.] the Metallic Sulphates by Hydrogen Gas. 341

was so small that it cannot be estimated. Whether this cobalt
originated from the matrix, or whether it was really a constitu-
ent of hair pyrites, cannot be determined. The second conjec-
ture is not improbable, as all other nickel-minerals contain
cobalt.

Another solution of the oxide of nickel in muriatic acid was
mixed with the liquid remaining after the precipitation with
caustic potash in c. Then a current of sulphuretted hydrogen
gas was passed through this liquid after it had been mixed with
a slight excess of muriatic acid. No precipitate fell, but the
liquid assumed a tint of yellow indicating the presence of a trace
of arsenic. If we subtract the O006 gr. of quartz from the
0*222 gr. of hair pyrites, subjected to analysis, there will remain
0*216 gr. which is composed of

Sulphur « 0-002

b 0-072

0-074 or 34-26
Nickel c 0-139 64-35

0-213 98-61

An atom of nickel weighs 739-51, and two atoms of sulphur
402-32 ; but 739-51 : 402-32 :: 64-35 : 35-02. Thus it appears
that hair pyrites is a compound of one atom of nickel and two
atoms of sulphur. It is not in the least affected by the magnet.

Protosulphate of Iron.

A determinate portion of pure protosulphate of iron, which
nad previously, by the cautious application of heat, been
deprived of its water, was treated with hydrogen gas. The salt
exhibited the very same appearances as sulphate of nickel under
the same circumstances. Sulphurous acid and water first came
over, and at last sulphuretted hydrogen gas. When the process
was concluded there remained a dark-grey agglutinated pulve-
rulent matter, which was strongly attracted by the magnet, and
dissolved in muriatic acid with the evolution of sulphuretted
hydrogen gas. The solution was not altered by muriate of
barytes. 0-858 gr. of anhydrous sulphate of iron, gave 0*396 gr.
of the new substance : 0*367 gr. of this new product were treated
with sulphuretted hydrogen gas. The weight was increased to
0-474 gr. ; but not the smallest portion of water was formed,
showing that sulphate of iron is changed by hydrogen gas into
a substance which contains no oxygen.

The experiment with the hydrogen gas was repeated on
1*012 gr. of sulphate of iron, and the residual matter amounted
to 0-479 gr. The residue in the first experiment was 46-15 per
cent, and in the second 47-33 ; the mean of which is 46*74. The

342 M. Arfwedson on the Decomposition of [May,

weight of Fe S° : : Fe S :: 100 : 46-82. I had thus obtained a
compound of an equai number of atoms of iron and sulphur ;
and consequently the body contained only half as much sulphur
as the compound, which we have hitherto called sulphuret of iron
at minimo. The increase of weight in the experiment with
sulphuretted hydrogen gas was too great to induce us to admit
that the product was Fe S- ; for the weight of Fe S : Fe S' : ::
0-367 : 0*450 ; whereas the experiment gave 0*474. But it is
known from Prof. Stromeyer's experiments,* that what we com-
monly call sulphuret of iron in minimo — a substance which may
be prepared artificially, and exists also as a natural production
known under the name of magnetic pyrites, is not Fe S" ; but a
compound which may be represented by the formula Fe S 4 -f-
6 Fe S 2 , so that it contains more sulphur than Fe S*. The con-
stituents per cent, of magnetic pyrites are :

Iron 59-85

Sulphur 40-15

100-00

Jn my experiment, 0-367 Fe S were operated upon, which
contain 0-283 iron ; the sulphuretted hydrogen gas augmented
the weight to 0-474. This new compound of course contains
0-283 iron and 0-191 sulphur, or in 100 parts, 59-7 iron and 40-3
sulphur. Thus the sulphuretted hydrogen had furnished the
quantity of sulphur requisite to convert Fe S into magnetic
pyrites.

Subsulphate of Iron.

This salt is obtained, as is known, when a smaller quantity of
caustic potash is added to a solution of persulphate of iron than
is requisite to separate the whole of the iron. As it contains
only one atom acid united to two atoms of the basis, I expected
that the hydrogen gas would have converted it into Fe- S. But
contrary to expectation, sulphurous acid and sulphuretted hydro-
gen were disengaged during its reduction 0-709 gr. prepared in
the above described way, and free from water, left for residue
0-422 gr. But a long time elapsed before the sulphuretted
hydrogen gas ceased to come over, although the mass was kept
in a full red heat. The matter was in appearance similar to
metallic iron, such as it is formed when the oxide is reduced by
hydrogen gas. It was acted on almost as strongly by the mag-
net as that, and was semimalleable, but it dissolved in muriatic
acid with the evolution of sulphuretted hydrogen. The quantity
of the reduced body, compared with that of the salt employed,
shows that the product was a compound of four atoms iron with
an atom of sulphur, or that the salt lost half of its sulphur, toge-

• Gilbert's Ann. xviii. 186.

1824.] the Metallic Sulphates by Hydrogen Gas. 343

••• •••

ther with all its oxygen; for the weight of 2 Fe -S : Fe 4 S ::
0-709 : 0-420. The residue in the experiment was only a very
little higher, or 0-422.

Thus to the sulphurets of iron already known, viz. Fe S 4 and
Fe S 4 , we can now add Fe S and Fe 4 S ; and probably that
series will be still further increased with Fe 2 S ; so that it will
be possible to exhibit a sulphate of iron, so constituted that the
number of atoms of the acid shall be equal to those of the base.

Sulphate of Lead.

The salt was decomposed by hydrogen gas with facility, and
sulphurous acid was disengaged, followed at last by sulphuretted
hydrogen. The product obtained was a mixture of sulphuret
-and metallic lead, which, towards the end of the process, had
melted together in small balls, which were quite malleable. On
the solution of the mass in nitric acid, a considerable portion of
sulphur was disengaged. 1-294 gr. of sulphate of lead pre-
viously exposed to a red heat, left for a residue 0*940 gr. Hence
it appears that a little more than half of the salt is converted
into metal, and the remainder into sulphuret of lead ; for the

weight of 2 Pb S* : Pb + Pb S 3 :: 1-294 : 0-952.

Whether in a higher temperature hydrogen gas cannot change
the whole sulphate of lead into metal, was not tried ; but it is
less probable, as we see by Berthier's experiments,* that if
sulphate of lead be mixed with charcoal powder, and heated in
a hessian crucible even to whiteness, there always remains a
mixture of metallic and sulphuretted lead.

. The preceding experiments were tried also with sulphates of
copper, bismuth, tin, and antimony ; but none of these trials
gave any very remarkable results. The copper and bismuth
salts were reduced to pure metals. The tin salt gave metallic
tin still mixed with some sulphuret, and from the antimonial salt
was obtained a residue of oxidized metallic and sulphuretted
antimony.

Article IV.

An Analysts of some Minerals, By Aug. Arfwedson.f

Cinnamon Stone from Mals/6.

During a mineralogical journey in Vermlaud daring the
summer of 1820, Prof. BerzefiuB met with a garnet mineral in
the lime quarry of Masjii, in the neighbourhood of Philspstad,

• Ann. ac Chim. July, 1822, p. 270.

+ Translated from the Kongl. Vctcntkaps Atademiens Handlingar, for 1892, p. 87.

344 M. Arfivedson's Analysis of some Minerals. [May,

which in its external characters bore a strong resemblance to
the cinnamon stone of Ceylon ; and he afterwards, by a compa-
rative set of experiments before the blowpipe, satisfied himself
that the two minerals possessed very similar characters. I hope
by the following analytical experiments to be able to show that
this mineral comes very near cinnamon stone even in its chemi-
cal composition.

By concentrated muriatic acid, the stone is not in the least
acted upon, at least not while cold, excepting that the few
attached fragments of calcareous matter are gradually dissolved.

1*526 gramme of the mineral purified in this way, and after-
wards reduced to a fine powder, were heated with three times its
weight of carbonate of potash. The fused greyish mass was
dissolved in muriatic acid. There remained a quantity of silica,
which, after being heated to redness, weighed 0*625 gr. (a).

The muriatic solution was precipitated with caustic ammonia
with the usual precautions to prevent the alumina from being
again dissolved ; and the precipitate which evidently contained
iron was collected on a filter, and washed with hot water. It
was again dissolved in muriatic acid, and supersaturated with
caustic potash ; by which the precipitate which fell at first was
again redissolved, with the exception of a little oxide of iron,
which, after exposure to a red heat, weighed 0-067 gr. Being
again dissolved in muriatic acid, it was found to contain 0*007
gr. of silica (b) ; consequently the weight of the oxide of iron was
0*06 gr. (c).

From the alkaline solution, the alumina was separated by
muriatic acid and carbonate of ammonia. Its weight, after
exposure to a red heat, was 0*321 ; but when dissolved in
sulphuric acid, it left 0*007 gr. of silica (d) ; so that the true
weight of the alumina is 0*314 (e).

From the liquid which had been treated with caustic ammonia,
and which had been again rendered neutral by a few drops of
muriatic acid, the lime was precipitated by oxalate of ammonia.
The oxalate of lime obtained was well washed with warm water,
dried, heated to redness mixed with a little liquid carbonate of
ammonia, and heated gently till all the ammonia was disengaged.
The carbonate of lime obtained in this way amounted to 0*920
gr. equivalent to 0*518 gr. of pure lime (f).

The liquid thus freed from lime was mixed with a sufficient
quantity of carbonate of potash, and evaporated to dryness. The
dry residue when dissolved in water left a substance, which,
after being exposed to a red heat, weighed 0*006 gr. and which
possessed the characters of oxide of manganese mixed with a
little magnesia (g).

A determinate quantity of the mineral in coarse powder was
exposed to a red heat in a platinum crucible; but lost no
weight.

1824.] M. Arfwedson's Analysis of some Minerals, 345

Thus the constituents of the mineral have been found to be :
Silica (a).. 0-625

(6) . . 0007

(d).. 0-007

. . Per cent.

0-639 or 41-87 containing oxygen = 21-06

Alumina 0-314 20-57 = 9-60

Lime 0-518 33-94 = 9-53

Oxide of iron .... 0-060 3-93 = 1-20

Manganese with

■&*

magnesia 0-006 0-39

1-537 100-70
We perceive from this table that the oxygen of the silica is
equal to that in the bases. Further, that the alumina and lime
have the same quantity of oxygen, and each eight times as much
as the oxide of iron. Thus the formula exhibiting the constitu-
tion of the mineral isFS + 8AS + 8CS.

Klaoroth's analysis of cinnamon stone from Ceylon gave*

F Silica. 38-80

Alumina 21*20

Lime 31-25

Oxide of iron 6-50

Loss 2-2o

10000
That result does not deviate far from mine ; but as far as
regards the smallest ingredient, oxide of iron, the considerable
excess of it occasions quite a different formula. It becomes F S
+ 4CS + 5AS. It is possible that Klaproth underrates both
the lime and the alumina, because he separated the former by
carbonate of soda, and the latter from its solution in potash by
means of sal ammoniac. His formula, therefore, may be a good
deal faulty. The formula which I found is considerably simpler,
and, therefore, more likely to be correct.

I conceive that we have thus found reason to consider the
mineral from Malsio just analyzed as a real cinnamon stone, at
least as long as Klaproth's analysis continues unrepeated and

unconfirmed.

Brasilian Chrysoberyl.

Our knowledge of the constituents of this mineral is derived
from Klaproth's°analysis,t according to which it is composed of

Alumina 71-50

Lime 6-00

Oxide of iron 1 '50

Silica 18-00

97-00
• Beitrage, v. 142. ♦ W* '• 102 -

346 M. Arfwcdson's Analysis of some Minerals. [May,

In a set of experiments which Prof. Berzelius made upon
almost all minerals by means of the blowpipe, he expressed his
opinion respecting this mineral that it did not contain lime as
an essential constituent, but that in all probability chrysoberyl is
a pure subsilicate of alumina.

I have found this opinion confirmed by the following analytical
experiments. On that account they may deserve to be stated in
this place.

Analysis.

0614 gramme of the mineral were reduced to a fine powder
in the agate mortar, and afterwards separated from all the
coarser particles by washing. This powder was mixed with a'
sufficient quantity of caustic potash, and raised to a red heat in
a silver crucible. After the heat had been kept up a full hour,
the mass was found in a state of semifusion. It was washed out
of the vessel with water, and treated in the usual way with
muriatic acid, which left undissolved 0*238 gr. This residue
was heated again with potash, and dissolved in muriatic acid.
The undissolved portion now weighed 0*137 gr. The heating
with potash was repeated still another time, and there now
remained undissolved by the muriatic acid 0*108 gr. which, on
examination, proved to be pure silica.* (a)

The solutions in muriatic acid were mixed with the water
employed to edulcorate the silica, and the liquid was precipitated
by caustic ammonia added in as small excess as possible. The
precipitate, after being well washed, and heated to redness,
weighed 0*507 gr. When dissolved in sulphuric acid, it left
0*007 gr. (/;) of silica, and the solution gave with caustic potash
a precipitate, which was again redissolved by an additional dose
of the potash, with the exception of some flocks of peroxide of
iron which could not be weighed. The matter dissolved by the
sulphuric acid was of course alumina, and its quantity (subtract-
ing the silica) was 0*500 (c).

For the greater security, the alkaline solution was saturated
with muriatic acid, till the precipitate was redissolved, after
which carbonate of ammonia was added in great excess. Had
any glucina or yttria existed in the matter, it would have been
dissolved by this excess of carbonate of ammonia, and would
have fallen when the filtered liquid was boiled till the excess of
ammonia was driven off; but the liquid stood this test without
any precipitate appearing.

The liquid which had been precipitated by caustic ammonia
was neutralized by muriatic acid, and mixed with some drops of
oxalate of ammonia ; but even after the interval of 12 hours, the
liquid had not the least appearance of turbidness ; nor could any

* To satisfy myself whether the silica be pure, I am in the habit of fusing it with a
good quantity of carbonate of potash. If the fused mass dissolve in water without resi-
due, 1 consider the silica as free from any admixture of foreign earth.

1824.] 3T. Arfwedson's Analysis of some Minerals. 347

precipitate be produced by boiling it after adding a little carbo-
nate of potash.

0*614 gr. of this mineral, therefore, contain

Silica (a) 0-108

(b) 0-007

0-115 or 18-73
Alumina (r) 0-500 81-43

0-615 100-16

18-73 silica contain 9-42 oxygen, and 81-43 alumina contain
38-03 oxygen; but 9-42 x 4 = 37-68. According to these
proportions, the formula for chrysoberyl is A 4 S.

Boracite from Luneburg.

Prof. Stromeyer states in a letter, of which an extract is
inserted in Gilbert's Annalen, xviii. 215, that he analyzed this
mineral, and found it a compound of 67 boracic acid and 33
magnesia. As Stromeyer's analyses have in general very justly
acquired the confidence of the public, we ought not to call their
accuracy in question upon slight grounds ; but as we are still
ignorant of the method of analysis which he employed, it is the
more difficult to give implicit confidence to his statement, that
all the methods hitherto known for separating boracic acid
from its combination, only accomplish their object in a very
imperfect manner.

In some of my experiments to extract boracic acid from its
compounds, I found that if a borate (for example, borax) be mixed
with three or four times its weight of finely pulverized and pure
fluor spar, together with a sufficient portion of concentrated
sulphuric acid, and the matter be afterwards heated to dryness,
and then exposed to a red heat, we can in that way separate the
whole of the boracic acid in the form offluoboric acid gas. The
quantity of the basis being then determined, which it may be
with precision, we obtain the true composition of the salt sub-
jected to analysis.* This analytical method may be applied to
all borates with incombustible bases, as far as they are decom-
posable by sulphuric acici ; and boracite being in this predica-
ment, I was in hopes that I had it in my power to repeat Stro-
meyer's analysis with the prospect of obtaining a correct
result.

* In two experiments made in this way, I have found anhydrous borax composed of

First Exp. Sec. Exp.

Koracicucid 686 69'2

Soda SW JO-8

I'M'-OO 100-00

348 M. Arfwedson's Analysis of some Minerals. [May,

In order to free the boracite as completely as possible from
all admixture of the matrix, consisting of gypsum, a portion of it
reduced to a fine powder was boiled repeatedly with water. It
was afterwards collected on the filter, washed, and dried.

0*849 oramme of it were mixed in a platinum crucible with
3 o-rammes of Derbyshire fluor spar in fine powder, made into a
paste with concentrated sulphuric acid, and then heated till it
was reduced to dryness, taking the requisite precautions to
avoid the dissipation of any portion from the effervescence, and
the evolution of the gas which took place. The dry mass was
then exposed to a red heat. For the greater security, the process
was repeated, but no fluoboric gas was disengaged ; showing
that the mineral had been completely decomposed by the first

process.

The sulphate of magnesia was then extracted by water, and
the undissolved portion was washed so long upon the filter that
I was sure none of the magnesia remained mixed with the gyp-
sum. The filtered water was then freed from the gypsum which
it contained in solution by oxalate of ammonia. It was then
evaporated to dryness, and exposed to a red heat. The salt thus
obtained weighed 0*758 gr. and possessed the characters of pure
sulphate of magnesia. The quantity of magnesia in it amounted
to 0-257, and consequently the remaining 0*592 gr. necessary to
make up the weight of the boracite must have been boracic
acid.

100 parts of boracite then contain

Boracic acid. 69*7

Magnesia 30*3

100*0

Gay-Lussac and Thenard found that boracic acid contains 33
per cent of oxygen. If this be the case, the oxygen in 69*7 is
23. 30*3 parts of magnesia contain, on the other hand, 11*73
parts of oxygen; but 11*73 x 2 = 23*26; so that boracic acid
contains twice as much oxygen as magnesia. As long as the
constitution of boracic acid remains disputed, I will not allege
this coincidence as a proof of the accuracy of my analysis ; but
merely as a circumstance from which Gay-Lussac and Thenard's
conclusions may receive some support.

1824.] Mr. Herapath on the Theory of Evaporation. 349

Article V.

Addition to Mr. Herapath' 's Theory of Evaporation in the Annals
for November, 1821. By John Herapath, Esq.

(To the Editor of the Annals of Philosophy.)

DEAR SIR, Cranford, April 12, 1824,

In Prop. 14 of ray theory of evaporation, it is said that the
absolute evaporation is not affected by the pressure of any super-
incumbent air. This is to be understood of the decomposition
at the surface of the evaporating body, and not of that escape or
dispersion of vapour which constitutes apparent evaporation.
Against the indiscriminate confusion of these things hints are
given, I believe, in more than one place in my theory ; but my
attention having been recalled to the subject by the kind inqui-
ries of the Rev. E. W.M.Rice, some views respecting the effects
of pressure by airs have occurred which I intend here to notice
in order to prevent misconception on certain points of my former

theory. .

If an evaporating surface were placed in an indefinite vacuum,
it is plain that little, or perhaps none, of the emitted vapour
would be recondensed on the body, but would expand into
space. But were any body as an air, for instance, to be con-
fined over the evaporating body, the particles of this air would
of course come in contact with many particles of the ascend-
ing vapour, and striking them in all directions some would
necessarily be beaten back on the evaporating body. Of these
a considerable portion would most probably be recondensed.
But whatever be the number recondensed, they will evidently be
as the number beaten back to the surface, and they as the num-
ber struck by the particles of the air. Again the number struck
in a given time must be as the number of particles of the air
which in the same given time would pass through or strike a
given space. Now this number multiplied by the momentum of
a single particle, that is by the temperature of the air, is equal to
the elastic force of the medium. The number of recondensed
particles, therefore, or the momentary effect of a superincumbent
air on the incremental evaporation is as the elasticity of the air
directly, and its temperature inversely. And as this is demon-
strated of no particular air, it is true of any air.

Hence, therefore, if two evaporating bodies of the same kind be
placed in any tivo airiform una) ' traded media, respectively of the
temperatures of their contained evaporating bodies, the momentary
effects of the media un the evaporations will be in a ratio com-
pounded of the elasticities directly, the incremental evaporations
directly, and the temperatures inversely.

And if the temperatures are equal, the momentary ejects are

350 Mr. Herapath on the Theory of Evaporation. [May,

directly as the elasticities and rates of evaporation ; and tvhen the
elasticities are equal, these effects are inversely as the temperatures,
and directly as the rates of evaporation. Of course in the same
fluid at the same temperature, the incremental diminution is as the
pressure directly.

It would be easy to reduce the above laws to a comprehensive
integral expression ; but as I know not a single experiment with
which it can be compared, I am not disposed to indulge in useless
calculations. Besides it appears to me there is another cause
Very materially influencing the quantity of apparent evaporation ;
and of which I am likewise destitute of any experiments to afford
me the least aid towards numerical comparison. It is this. In
the above views we have regarded the superincumbent air as
totally devoid of gravitation, and affecting the evaporation by
its elastic force only. This however seems not to be the whole
operating cause. Though by our theory, confirmed by expe-
rience, all airs in contact pretty rapidly intermix, and the rising
vapour is therefore incessantly intermixing with the surrounding
air, yet when the temperature is high, the vapour must evidently
be liberated faster than the dispersion by intermixture can pro-
ceed; and consequently the relative specific gravities of the
vapour and surrounding air tend much to suppress or elevate the
vapour. A heavier air would accelerate the ascent of the vapour,
and by this means contribute to diminish the recondensation ;
and hence increase the apparent evaporation. But an air as
light or lighter than the vapour would not favour the vapour's
ascent, and would, therefore, diminish the apparent evaporation
by increasing the recondensation. Consequently if the evapo-
rating fluid, its temperature, and the pressure of the superincum-
bent air be the same, the greater the specific gravity of the surround-
ing air, provided it exceed that of the vapour, the greater the
apparent evaporation.

I am not aware that this phamomenon has ever been noticed ;
but if philosophers who may be engaged on this part of physics
would have the goodness to attend to these hints, they may pro-
bably unfold an interesting set of laws, and add something
perhaps important to our present stock of knowledge.

Several ways have occurred to me of evolving the temperature
in a function of the quantity of water left, supposing evaporation
alone to affect the temperature, and that at a given temperature
there was a given quantity of water ; but the utter defect of
experiments again prevents my proceeding. However the
following views of the subject rust on principles so simple and
susceptible of modification, if experiments should require it, that
I am induced to give them a place here, if it be only to excite
philosophers to present us with some experiments on this inte-
resting part of evaporation. Though in my theory of evaporation
I have said that the vapour arises from a decomposition at the
surface, it is evident that no theoretical views only can furnish

1824.] Mr. Herapath on the Theory of Evaporation. 351

us with the fact, whether this decomposition takes place at the
mathematical surface, or at a very small distance beneath ; nor
can we from theory alone decide whether the vapour and its fluid
have a common temperature, or even nearly so, before the former
quits the latter. The well-known fact that the vapour freely
ascending from boiling water is, near the surface of the water,
not at the very reduced temperature to which the decomposition
alone would have brought it, but at the temperature of the
water, tends certainly to favour this idea. Hence if it be assumed
that every portion of vapour when it quits the water has the
same temperature as the remaining water; and if w be the quan-
tity of water, t its temperature, and dw the momentary evapora-
tion, we shall have by Cor. 1, Prop. 20, Annals for Dec. 1821,

— g-^- for the number of vaporous particles in d w. Therefore,

t K' 6 t TV

11, , 6 w + 5 dw

——■ a iv + w — a u 1
6

i s the common temperature to which the water and vapour
would be reduced by the decomposition of dw quantity of water.
Consequently,

, 6 t w b t d -w

6 W + 5 d iv 6 re + 5 d r<''
d t H d w

or, — = - . —

t D W

whose integral is t = A w*,
A being an arbitrary constant equal to

U

5

"'-6

where /, and w, are known corresponding, or the primitive values
of I and w.

If, therefore, the transmission of temperature by water was
instantaneous, and every portion of vapour had its temperature
equalized, as soon as formed, with that of the remaining water,
and then quitted the water entirely, the temperature would be as
the quantity of water left raised to the £th power; provided
evaporation only interfered. But we know that water is not
what is called a perfect conductor ofheat, and therefore that the
above law is not mathematically true. As the evaporation,
however, is generally but trifling, unless in high temperatures,
this theorem may probably be found a tolerable approximation.

Were the number of the particles increased in the ratio of
1 to /'by the decomposition, we should have

I = A w'-\

If, therefore, r — 100, t a w". Hence if 7/- be diminished
by a hundredth part only, the values of/ corresponding to ir =c

352 Mr. Herapath on the Theory of Evaporation. [May,

100 and w = 99 will have a ratio equal to that of 1 to *36973,
or 100 to 37 nearly. And therefore if the true temperature
corresponding to w = 100 be 1172-6 or 212° Fahr. the true
temperature corresponding to w = 99 will be only 433*5, or
about — 361° Fahr. ; so that here for a loss of weight of only
the x^-g-th part, the temperature would be sunk nearly 600° of
Fahr.

We see from the preceding calculation that where the number
of particles is much increased by the decomposition, a very
trifling or even an utterly inappreciable loss of weight may
nevertheless be accompanied by a very considerable diminution
of temperature. Hence may easily follow the phenomena of
radiation, and even those of the emission of light. Indeed I am
fully convinced from many circumstances that evaporation,
radiation, and the emission of light, are phenomena similar in
kind, and governed by similar, but not precisely, the same laws.
Probably the chief difference lies in the inequality of magnitude
in the particles when decomposed. Light is most likely the
particles decomposed into their smallest parts, which, if they
could be inclosed within a vessel whose pores would not allow
them a passage, would form a body similar to gas or vapour of
extreme levity ; and, on the contrary, if vapour was formed in
vacuo, its particles would fly off in direct lines, like light with a
great velocity. These views are rendered interesting not merely
from their simplicity and their reducing to one simple cause
phenomena apparently so very different as vapour and light, but
they take from the sun that exorbitant temperature which cer-
tain philosophers have hitherto supposed it to have, and thus
render it much more fit for a habitable globe. For since the
molecules of light are conceived to be many times less than the
particles of common matter, they would have with only the
same momentum or temperature a velocity many times greater
than the latter ; and, therefore, after a particle of common mat-
ter had been struck by a molecule of light, and was returning to
the other particles of the body of which it formed a part, it may
be overtaken and struck again and again before it reached them
by other molecules, each impulse of which would add to its
motion, and therefore to the temperature of the body ; and if the
rays of light be condensed by a mirror or lens on any particular
body, the probability of this augmented temperature would be
in proportion to the density of the light. Hence, therefore, the
sun may in reality have a temperature not higher than that of
any other body of the system, and yet produce all the effects
attributed to it. This idea comes up nearly to that broached
by the late Sir W. Herschel, but without the aid of his luminous
atmosphere. I need, I hope, scarcely observe, that these reite-
rated impulses by different molecules of light on the same parti-
cle of matter, do evidently not at all affect the theory of gases
I have heretofore laid down.

1824 .J M. Rose on Analcime, Copper Pyrites, Sfc. 353

It was my intention here to extend the theorems I have
published in my theory of evaporation, and to add some new
ones since discovered respecting the " conducting power " of
gases, the agreement of which with the experimental laws of
Dulong and Petit, contributes another strong link to the chain
of evidence adduced in favour of my views ; but as I may at some
period print something in a separate form on the important
subjects I have discussed in various parts of the Annals, 1 intend
to reserve these, and other things which I have been able to
effect in different parts of the physical sciences, to that oppor-
tunity.

Article VI.

Chemical Examination of Analcime, Copper Pyrites, and Sul-
p/utret of Bismuth. By M. Rose.*

The first research into the composition of analcime was made
by M. Vauquelin. He found this mineral to contain

Silica 58-0

Alumina 18-0

Water 8o

Soda. 10-0

Lime 2-0

Iron Trace

96-5

The analcime which I analyzed is found in the valley of Fassa,
in the Tyrol; the crystals were trapezoidal, and were in some
parts of a slight red colour; but the analysis indicated scarcely
perceptible traces of oxide of iron : the crystals were translucent,
and free from other impurities. The analcime reduced to pow-
der, lost, by being strongly heated, 8-27 per cent, of water,
which was slightly alkaline. By heating some fragments to
redness, ths loss in different experiments amounted to 8*80,
8-86, and 8-96 per cent. The analcime lost its transparency,
and became a white enamel.

The analysis of analcime is not complicated, since it is very
easily decomposed by acids, when it has not been heated, and
is reduced to powder. On this account it is not requisite to
employ nitrate of barytes used by M. Vauquelin, and which
always occasions more or less loss. When digested in muriatic
acid, it formed a jelly, which was dried, and afterwards treated
with muriatic acid diluted with water to separate the silica. The
filtered solution contained neither lime nor magnesia, and was

• Extracted from the Annalcs de Chimie et de Physique, torn. xxv. p. 192.

New Series, vol. vn. 2 a

354 M. Rose on Analcime, [May,

decomposed by carbonate of ammonia ; the precipitate, except
a slight trace of silica and oxide of iron, was dissolved by
potash. The solution, after the silica and alumina were sepa-
rated, was evaporated to dryness, and the residuum was heated
until all the muriate of ammonia was volatilized. The residuum
gave cubic crystals of common salt free from potash. The
results of the analysis were :

Silica , 55-12

Alumina 22-99

Soda 13-53

Water. ...•••• 8 * 27

99-91

I found upon trial that the white transparent analcime which
is found in the lava of Catana, in Sicily, was of similar composi-
tion ; but the quantity I possessed was too small to make a com-
fdete analysis, and the fragments were mixed with carbonate of
ime.

I analyzed another analcime from Fassa, different from that
which I have just mentioned, and I found that its composition
agreed perfectly with that of the preceding ; the results of the
analysis were

Silica 56-47

Alumina 21-98

Soda . < . . ,\ 13-78

Water 8-8i

101-04

This analcime was of a flesh-red colour, on which account the
name of sarcolite has been given to the analcime of Montecchio
Maggiore, near Vicenza, and in which M. Vauquelin found

Silica , , 50-0

Alumina 20-Q

Water 21*0

Soda and potash 4*5

Lime 4-5

Iron Trace

100-0

I cannot explain the great difference between M. Vauquelin's
analysis and mine ; I think I have, however, some reason for
supposing that the sarcolite which he analyzed was not quite
pure ; for sometimes the large crystals of analcime which are
found in the valley of Fassa, are so filled with perfectly well
defined crystals of apophyllite, that they form almost half the

1 §24.] Copper Pyrites, and Sutyhuret of Bismuth. 355

mass. In the crystal of analcime which I analyzed, I found a
crystal of apophyllite of an inch long. It is sometimes difficult
to separate the mass of the analcime from these crystals of
apophyllite ; the latter, however, are discovered by their pearly
lustre, and especially by their distinct cleavage, which is parallel
to the plane perpendicular to the axis. It follows nevertheless
from my analysis, in which I could discover neither lime nor
potash which occur in apophyllite, that the fragments which I
employed were perfectly free from this substance.

Copper Pyrites.

There are many analyses of copper pyrites ; but they do not
present any probable formula, and differ from each other. I have
analyzed three sorts of crystallized copper pyrites, and I found in
all of them the same proportions of constituent parts.

The analysis of copper pyrites, although very simple, never
gave me results which corresponded with a probable formula,
when I separated the oxide of iron from the oxide of copper by
pure ammonia. The oxide of iron precipitated always contained,
even after having been perfectly washed, a considerable quantity
of oxide of copper, which I could not separate if I did not preci-
pitate the copper from the muriatic solution of oxide of iron by
means of sulphuretted hydrogen.

I dissolved in each analysis of copper pyrites, two different
quantities in aqua regia. I precipitated one of the solutions by
muriate of baryles to determine the quantity of sulphur by the
sulphate of barytes obtained, and I poured into the other pure
ammonia in excess. The oxide of iron precipitated was heated
to redness, and dissolved in muriatic acid, which always left a
small quantity of silica. I then treated, as already mentioned,
the solution with sulphuretted hydrogen.

I obtained the following results from two varieties of crystal-
lized copper pyrites from Ramberg, in Sayn, and from Fursten-
berg :

Ramberg. Furstenberg.

Copper 34-40 33-12

lion 30-47 30-00

Sulphur 35-87 30-52

Silica 0-27 0-30

101-01 100-03

The analysis of the crystallized copper pyrites from Freiberg,
gave no similar results.

Sulphwet of Bismuth.

This sulphuret from Riddarhyttan, in Sweden, I found to
possess the same composition as the artificial sulpluuet of
bismuth ; namely,

2 a 2

356 Mr. Walker on some Geometrical Principles [May,

Sulphur 18-72

Bismuth 80-98

99-70
The artificial compound gave

Sulphur 18-49

Bismuth 81-51

100-00

Note. — In this abridgment of M. Rose's paper, I have not
given all his views of the atomic constitution of copper pyrites ;
for as he adopts the numbers of Berzelius in which the weight of
the atom of iron is double that generally admitted in this country,
the statements would be useless. He considers its probable
composition as one atom of sulphuret of copper with three atoms
of sulphuret of iron. It will, however, appear, that his analysis
of copper pyrites from Ramberg comes more nearly than mine to
what I have supposed to be the atomic constitution of this com-
pound ; namely, a compound of two atoms of protosulphuret of
iron and one atom of persulphuret of copper, or in 100 parts of

Copper 34-78

Iron y 30-44

Sulphur 34-78

100-00
(See Annals, N. S. vol. in. p. 301 .)—Edit.

Article VII.

A Memoir on some Geometrical Principles connected with the
Trisection of an Arc. By John Walker, Esq. formerly Fellow
of Trinity College, Dublin. (With a Plate.)

(To the Editor of the Annals of Philosophy.)

SIR, April 14, 1824.

The following propositions I believe are new ; and, if I mis-
take not, they either extend, or promise to extend, the limits of
Plane Geometry.

It has long seemed to me, that the moderns have too much
abandoned the attempt of trisecting an arc, by the right line and
circle. We know with what ardour the solution of that problem
was sought by the ancient mathematicians ; as well as how con-
siderably the science was advanced by their investigations,

• : ^-

<?/;;

c$

: i r .TTIY/.

I

ZngrawHbrthcJimats offhiktsophj _ tin Hnidivm fradnek & Tcv.Mwj.2St4

1824.] connected with the Trisection of an Arc. 357

though they failed of arriving at the ultimate object which they

Eursued. And I believe that geometrical science would not
ave remained as stationary, as it has been for many years, if the
problem had continued to share the attention of modern geome-
ters.

But nothing so much paralyzes exertion as despondency of
success ; and I am aware that some of the most profound mathe-
maticians of the present day do not hesitate to pronounce, that
the problem alluded to is impossible. Their assertion is, I think,
unwarrantable and rash. If I may hazard an opinion, in which
many will think me over sanguine, I avow my expectation that
some of the principles, which I offer in this Memoir, will yet lead
to the solution of that problem ; though I am now obliged to
dismiss the subject from my mind, on account of other avoca-
tions and declining health.

Prop. I. Problem. (Plate XXVII.) Fig. 1.

In a given segment of a circle to inscribe a triangle, whose
sides shall be in arithmetical progression.

Let the given segment be A b a. From B, the vertex of the
opposite segment, draw the lines B T, B t, trisecting A a in T
and t, and meeting the periphery in E and e. From A inscribe
the chord A x equal to E e ; and draw ax. I say that A x a is
the triangle required.

Dem. — Let y be the point in which a x intersects E e. Draw
T y : and parallel to this draw x z, meeting A a in z, and inter-
secting E e in s. Lastly, draw E z and sf. I shall now prove
that a x is equal to a z, and that E z is perpendicular to A a ;

whence it will follow that a z, or a x = —£■ + — , and is there-
fore an arithmetical mean between A a and E e, i. e. between
A a and A x.

For the triangles B T t, a t F are similar [having the angles at
t equal, and als'o the angles at B and a, as standing upon equal
arcs]. .-. B t : T t : : (a I) T t : t F. .'. rectangle B«F =
T t 1 ; and 2 B * F = 2 T t* = rectangle A t a = B t e. :.te
is bisected in F. .-. the similar triangles at F,y e F are mutually
equilateral, and y e = a t = T t . .'. e t is parallel to yT,
and /. to xz. .'.ax = a z. But also E y is bisected in s [for
the triangles* E y x, a y e, and x y s, ¥ ye, being similar, E y :
(y x) y s :: a y : (y ej y F :: 2 . 1]. .•. E s — z T, and E z is
parallel to s T," and perpendicular to E e. /. a z (or a D + D z)

i. e. a x = ^- + ?— = A a * A * . .'. a x is an arithmetical mean

between A a and A x. Q. E. D.

Cor. 1. (Fig. 2.)— The lines A b, a b trisect the line Ee; for
since the line t e bisects the angle A e a, A e : (a e) A E :: A t :

• The linca E jr, t a, are not drawn in the figure, but may be easily supposed.

358 Mr. Walker on some Geometrical Principles [May,

a t :: 2 : ]. .•. A b, bisecting the angle EA«, cuts E e into
segments in the same ratio.

Cor. 2. (Fig. 3.) — Drawing the diameter E p, and the line Ap,
the latter bisects the radius B c in q, and trisects B E in r. Let
jN be the point in which E P, perpendicular to E e, intersects
A p. The triangles ~E~N p,ey a are similar [for the angles at p
and a stand on equal arcs, as also the angles NEp and A ux ;
but A ax = aye']. .-. EN : E p.: y e : y a :: I : 2. vEN
= radius. .-. cq = semiradius. But the triangles ENr,Byr
are similar. .-. Er : r B :: EN : q B :: 2 : 1. .-. E B is trisected
in r. It is plain, that if from E we draw E g parallel to Ap, it
must bisect the radius b c in Q.

Cor. 3. (Fig. 3.) — Drawing through Q an ordinate (which is
the base of an inscribed equilateral triangle), the lines Be, b g
intersect this ordinate in the same point o. For the arcs A E,
p g being equal, as also the arcs E b, p B, .-. the arc A b = Bg.
••• b g is parallel to A B. .-. the triangle B h b is isosceles.
But its altitude h c is trisected by B e [as Be trisects a D].
.'. the side b h is bisected by B e in o. [For universally, if from
an angle at the base of an isosceles triangle a line be drawn cut-
ting the altitude and leg, the segments of the leg are to each
other as the upper segment of the altitude to twice its lower
segment.] But the ordinate through Q, the middle point of b c,
must also bisect b h . .-. &c.

Cor. 4. (Fig. 4.) — Let ibe the point in which the perpendicu-
lar from e meets a B. E? is parallel to A B. For drawing i I
parallel to A a, and cutting B E in r, this parallel is trisected in
r; and from the similarity of the triangles E I r, Bur, BE is
also trisected in r. .-. the triangles B r I, Er; are similar.
/.IB and E i are parallel.

Scho/utm. — In the assigned solution of the preceding problem,

the base of the given segment is always one of the extreme sides

of the triangle ; and the other extreme is the chord of the arc

intercepted by the trisecting lines. But if the given segment

contain an angle of less than 60°, its base may be the middle

side of an inscribed triangle, having its sides in arithmetical

progression. And from what has been established, it is plain

how we may construct that triangle. Let a x (fig. 3) be given as

the middle side of such a triangle, in the segment a B x. Then

we have e, the middle point of the arc ax. .-. we have P, the

opposite extremity of the diameter e c P ; and .-. we have a P.

But we have seen (Cor. 2) that a P bisects the radius B c in q.

If, therefore, with the centre c, and the interval of the semiradius,

we describe a circle, its occurse with a P determines the point

<j. .-. we have the diameter B b, and .-.its ordinate a A, one of

the extreme sides of the triangle ; the greatest or the least,

according to the point of intersection of the described circle

with the line a P, through which we draw the diameter.

1824.] connected with the Trisection of an Arc. 359

Prop. II. Problem. (Fig. 3.)

In a given circle to inscribe a triangle, whose sides shall be in
arithmetical progression, and their common difference equal to
a given line.

The solution of this problem also is obvious, from what we
have established in solving the former. For there we have seen
that A * is the common difference of the sides, and (Cor. 2) that
E N is equal to radius. Therefore, given the radius and common
difference of the sides, we can construct the right-angled triangle
AEN, having one of its sides inscribed in the circle, its hy-
potenuse E N equal to radius, and its altitude A z equal to the
given common difference. This line A z produced gives the
greatest side A a ; whence we have the other two.

Scholium. — Whenever the given common difference is less than
half the radius, we may find two different triangles to solve the
problem ; for either of the unequal sides, A E or A N, may be
inscribed in the circle. It is plain that A z is a maximum, when
equal to half E N ; that is, that the semiradius is the greatest
possible common difference of the sides.

Putting unity for radius, the triangle of whose sides the com-
mon difference is a maximum, is

V i + i y i yi-\

2 ' 2 > 2

the cosine of whose middle angle is -J. And it may here be
briefly remarked, that in the two different triangles, whose sides
have any smaller common difference, half the sum of the cosines
of the middle angles is £. Also, the sum of the two least angles
is the supplement of the sum of the two greatest ; and is the
third part of the difference between the sum of the greatest and
the sum of the middle angles : just as in the triangle

V 7 + 1 -y/7 VI - 1
2 ' 2 * 2 '

the least angle is the complement of the greatest, and is third
part of the difference between the other two.

Many other and curious properties of these triangles might be
6tated ; but we must hasten at present to other matter.

Prop. III. (Fig. 5.)

If on the same base A a there be two isosceles triangles,
whose vertical angles ABa, A E a are as three to two ; and
from the vertex of the smaller angle lines be drawn (E T, E t)
trisecting the common base; these lines will trisect (Aba) the
are of the circumscribing circle on which the greater angle
stands.

Dem. — Produce the altitude E o, and let o e = o E. Draw
e A, and produce it to f. E T trisecting the altitude of the
isosceles triangle E A e must bisect the leg A e in 1). Draw D d
parallel to e L; also the radius A c, cutting E T in m, and D d

360 Mr. Walker on some Geometrical Principles [May,

in n. Lastly, from the centre c, and parallel to A E, draw c Y
meeting E T in Y ; which point we shall prove to be in the peri-
phery of the circle.

From the similarity of the triangles c m Y, A«E, cm : A m
:: c Y : A E. But we shall prove that cm : A m :: A c : A E ;
and .*. that A c = c Y. For the triangles c m E, m n D, being

similar, c m : m n :: c E : D n ; that is, c m : :: c E : —

/. c m : A m :: c E : E e. But c E : E e :: A c : A e on ac-
count of the bisection of the angle y A c by the line A E]. .•. cm
: A m :: A c : (A e) A E. But we have before seen that c m :
A m :: c Y : A E. .*. c Y = A c, and the point Y is in the peri-
phery. But the angle b c Y being equal to b E A, that is, to the
third part of A B a, the line E T Y trisects the arc A b a in Y.
Q. E. D.

Cor. 1. (Fig. 6.) — If from p, the point where A c meets a E,
the line p d be drawn to the middle point of A E, and be pro-
duced on each side to meet the periphery in a and q ; the line
<r dp q is the side of an equilateral triangle inscribed in the circle
ABoi; and if the lines E ce, E q be produced to meet the
circle A E a e in m and n, the triangle E m n is an equilateral
triangle inscribed in that circle.

For the triangle A p E is isosceles [for angle p A~E — c A~B
+ BAE = BEA + 2BAE=2BEA = AE|)] : .:p d is
perpendicular to A E, and .*. bisects the parallel radius c x per-
pendicularly. .•. a q is the side of an equilateral triangle, of
which Y o is the altitude. Now drawing the line A e, it must

pass through y [foro A e = a E e = — - — = a A y~[. .•. Ay is

parallel to p d; and .'. E y, the hypotenuse of the right-angled
triangle E A y, is bisected by p d. But it is also bisected by
Y x. .'. E y and & q bisect each other in o. .*. tn E q y is a
parallelogram. .*. the angles «Ef and <j(Ec are each of them
30° [for ffEf = (cE;/ — y E 6 = qy E — x y E = qy x =
30°, and in like manner, q~Ec = q E 3/ +yE J = «^ E +
a'3/ E = q y x = 30°]. .*. raE n is an equilateral triangle
inscribed in the circle AEa«.

Cor. 2. — The arc B a is the third part of A « B, and B q the
third part of A a B. For <eY q being an eauilateral triangle,
arc a, Y = 2 «. x. But A Y = 2B,r. .-. a Y - A Y = 2 <e B.
.-. &c. In like manner 5 Y + A Y = A Y q = 2 B q v &c.

Cor. 3. — If from c be drawn a parallel to A a, meeting A Ein
k, and Y E in /, Y / is the third part of Y E. For the triangles
ex. E and c z k are each of them isosceles. /. k E = diameter.
But from the similarity of the triangles klE, c IY, Y I : I E :: .
c Y : k E :: 1 : 2. .-. Sec. It is plain (hat vz must cut off another
third part of E Y. Also, that c k= Y y.

Cor. 4. — Producing A c and A B to meet the circle A E a e in
r and s, the chord E r is equal toAo; and the semicircular arc

1824.] connected with the Trisection of an Arc. - 361

t E u is bisected in s. For angle A E a = E A r, the triangle
A p E being isosceles. .-. A a = Er. But arc E t = — -, and

arc Es = — . .•. arc £ s = — — = quadrant.

Cor. 5. (Fig. 7.) — If By'be drawn parallel to A E, it is equal
to E c. For drawing^/'g parallel to the axis, and meeting A E
in g,fg = g Z, on account of the equality of the angles g Z/,
g/Z. .-.fg + B c, or Ec, = g Z + E Z = B/.

Pkop. IV. (Fig. 7.)

The same things being supposed, E r the segment of the tri-
secting line intercepted between the two circles is the third part
of EX, the segment of it included in the circle AE«e.

Dem. — Draw A n, making the angle EA« = AEi, and
cutting E X in s. The triangles E A n, AE.r being identical,
A» = Ei=EX. But E X trisecting A a, and being parallel

to a n, trisects An. .'.As being equal to — ^, s X = — . But
A s, and .'. s X, = s r, the angles at the base of the triangle
A s r being equal. [For angle A r s = ' = AEc. But it

also equals A Er + E A r. .-. angle E A r = X E e. .*. angle
r A s, or E A n — E A ;•, = AEX-,rEe = A E e = A /• sj.
t? EX

Cor. — Drawing a r v, r v = ",-. For the triangle a r X is simi-

lar to A E « [for angle a r X = A E a, and angle rXa = EAa].
V a r = r X, and .-. r v = E r. .-. &c.

Scholium. — It is plain that A n bisects Ej/ in o ; since Ao =
E o, and the angle E A y is a right angle.

Prop. V. (Fig. 7.)

The same things being supposed, if there be drawn a diameter
of the circle A E a e perpendicular to the axis, and meeting the
circle A B a b in T, the line E T is a tangent, and equal to E /,
the line drawn from E to the point where z Z produced meets
the circle A E a e.

For a Z passes through k, the centre of the circle AEae; and
the triangle Z k c is isosceles, and similar to the triangle E Z c.
.-. c E : cZ::cZ:ck; that is, c E : c T :: r T : c ft. ^ .-. the
angle c T E is a right angle, and E T a tangent. .-. E T- =

(r E . E k) = (^ . 2 E ft) = (E d .Ee) = Et*. .: E T =

E /.

Cor. — Hence it appears, that if c T E be a right-angled trian-
gle, in which from the right angle the perpendicular T ft is let

362 Mr. Walker on some Geometrical Principles [MAy,

fill on the hypotenuse ; and if with c as the centre, and the side
c T as radius, a circle be described, and another circle, with k as
the centre and the remote segment k E as radius, intersecting
the former in the points A and a ; the angles A E a and A B a
are as two to three. That the circles may intersect, the side cT
must be more than half the hypotenuse ; or the angle c E T must
be more than 30°.

Prop. VI. (Fig. 8.)

The same things being supposed, the line Y x, joining the
point of trisection in the arc Aba with the point in which the
other trisecting line meets the circle A E a e, is a tangent to

the circle A Eae, and is equal to Y y, the chord of arc — — .

For the line A Y is a tangent at A, the angle a A Y being equal

to — — — = A E a. .*.A Y, or Y y, is a mean proportional

between E Y and X Y, that is between E y and x y. .'. the tri-
angle y Y x is similar to the triangle Y E y. .'. Y \r = Y y, and
is a tangent at x, the angle ;iE being equal to E X x.

Cor. ] . — Let there be drawn B m, B n parallel to the trisecting
lines ; and let & q be the base of an inscribed equilateral triangle
parallel to A a : — then the arc m a is the third part of z a r, and
therefore m q the third part of z A r. For the triangles YEy,
yYx being similar isosceles triangles, the angle EYi (stand-
ing on the arc z a r) = E Y y — Y E y = Bra » — mBr.
.*. arc x«r = nflB- 2 b n. But arc n a B = semicircular

arc B b — b n. ,\ arc zar = Bb— 3bn. ;. '—=- = -a bn

= b q — b n = n q t or m e.

Cor. 2. — B m is equal to y r ; and y r passes through k, the
centre of the circle AE«e. For arc BAm=BAY + Y in
= ~Bay+~Br = r ay. .'. B»« = ry. But we have seen that
X y = ay. ,\ ky bisects aX. perpendicularly. /. angle a ky =

" Q - = a E X. And angle a k e = a E A. .•. angle y k e =

A E X. But the same is the value of the angle which ry makes
with the axis. For the sum of that angle and Y E b = Y r y
a AEJ = AEY + YEJ. ■'• r y passes through k.

Prop. VII. (Fig. 9.)

In the produced diameter of a given circle A B a b, let E be
any point whose distance from the vertex is less thaii radius ;
and from E to the extremities of the normal diameter, let there
be drawn the lines ED, Erf, cutting the circle in the points
m and n. Let k be the point in which the lines Tin, dm cut
the axis ; and with the centre k and the interval k E let a circle
be described cutting the given circle in the points A, a. Then
the angle A E a is two-thirds of the angle A B a.

1824.] connected with the Trisection of an Arc. 363

Dem. — Draw the radii A c, A k. The triangle c k D is similar
to the triangle c D E, each being similar to dnD. .-. E c, c D,
c k are in continued proportion, that is, E c, c A, c &. /. the
triangle c A; A is similar to c A E. .•. angle c A /c = A E c =

— — . But angle A c b, or A B o, = c A k + c k A = 3 c A &

= 3 A E c. .-. ano;le A B a = — — A

Prop. VIII. (Fig. 10.)

If the angles A E a, A e a be two-thirds respectively of the
angles A B a, Aba, and if there be drawn from E and e the
lines E T, e t, each making an angle of 30° with the axis ; these
lines meet each other in the periphery of the circle A B a b.

Dem. — The lines E T, e t trisect the arcs A B a i Aba
respectively in T and t (see Cor. 1, Prop. III). Let the line ET
meet the circle again in C, and draw the ordinate C c. The

angle C B c = 60° + ^- [for C B b = C E b + BCE = 30°
+ — g— .*. &c.J. In like manner, the angle at b subtended by
the ordinate drawn through the point in which e t again meets

the circle is equal to 60° -\ — . But the two angles 60° +

— — - and 60° -\ — are supplemental to each other, the angles

—^- and — — - being together equal to 60°. Therefore, the for-
mer angle [60° H ^-\ being equal to C B c, the latter (60° +

■■ ■ ■-) must be equal to C b c. /.the ordinate drawn through the

point in which e t again meets the circle coincides with C c, and
e t meets E T in C.

Cor. 1. — The sum of the angles A E e, A e E being 60° [as
they are respectively the thirds of two supplemental angles], it
follows that the angle E A e = 120° = E C e. Therefore a
circle described with the centre c and radius c C must circum-
scribe the triangle EAe, And in that circle E e is the side of
an equilateral triangle.

Cor. 2. — Producing A a to meet the circle A E D e in d, the
angle A E d = 30° + A E a. For angle c E A = D E d, each
of them being equal to C E A. .*. angle dE« = DEca 30°.
But angle A E d = d E a + A E a = 30 9 + A E a.

From the principles which have been established, we should
be warranted immediately to infer the following proposition.
But I think it expedient to demonstrate its truth independently
of the preceding theorems.

364 On the Crystalline Forms of Artificial Salts. [May,

Prop. IX. (Fig. 11.)

If E e be the side of an equilateral triangle inscribed in the
circle whose centre is c, and A b any chord intersecting it per-
pendicularly in o ; assuming o a equal to A o, and drawing the
radius c a z, I say that the angle at the periphery A £ e is the
third part of the angle at the centre a c z.

Draw e r perpendicular to E e, and therefore equal to radius.
Then a b — e r [for drawing r s perpendicular to A b, it is plain
that a b = o s = e r]. Since therefore the three lines e r, a b,
c D are equal and parallel, the lines e c and r D, a c and b D are

\ r e

parallel. .*. angle e cz — r~D b = AEe = — — . .'. e c z, or

AEe, = ^f-. Q.E. D.

I here dismiss the subject for the present, probably for ever ;
yet not without a hope that some other qualified person may be
induced to pursue the train of investigation, which I have
pointed out. I have hazarded the expression of my opinion,
that it will yet lead to the trisection of an arc by plane geome-
try. I even suspect that I see how the trisection of the arc
A ed (fig. 10) may be derived from the trisection of the arc Aba.
But I must resign it into other hands.

Article VIII.

On the Crystalline Forms of Artificial Salts.
By H.J. Brooke, Esq. FRS.

(Continued from p. 288.)

Per chloride of Carbon.

I am indebted for these crystals to Mr. Faraday. Their
planes, although very brilliant while inclosed in the bottle on
whose sides they have been deposited, soon become dull on
exposure to the air. I have not found them
cleavable in any direction, but a right rhom-
bic prism may be regarded as their primary
form.

P on M, or M'.

P on c

P on h

c on h

« • • .

90°
119

90
150

M on M' 122

Mon/i 119

0'

40

20

Miniate of Cobalt.
These crystals, which I have received from Mr. Cooper, may

Hence

1824.] Apparatus for producing Instantaneous Light. 365

be cleaved with ease parallel to the terminal plane P, and less
distinctly parallel to M and M' of the annexed figure.
an oblique rhombic prism appears to be its
primary form.

PonM.orM' 109°

P on h 122

Pone' 106

h on c 131

M on h 128

31'

20
20
20
40

nTSO*

,-^

M !

A

TUL

,^r^

i...

'"•■•^v

MonM' 77 20

Acetate of Barytes.

From the crystals of this salt with which Mr. Cooper has sup-
plied me, it appears that the primary form is a right oblique-
angled prism. There is a bright cleavage
parallel to T, one less bright parallel to M,
and an indistinct one perpendicular to
these.

M on/ 146° 18'

MonT 113 12

Monrf 116 56

dond' 126 8

Ton/" 100 30

Article IX.

Apparatus for producing Instantaneous Light. By the Rev.
J. Gumming, MA. FRS. Professor of Chemistry in the Uni-
versity of Cambridge.

(To the Editor of the Annals of Philosophy.)

DEAR SIR, Ctimbiidge, April 15, 1824.

In the early part of last December, I exhibited to our Society
Doebereiner's experiment, of the inflammation of hydrogen in
atmospheric air by precipitated platina ; and from that time to
the present have occasionally employed the same apparatus for
producing an instantaneous light. The method I have used is
so simple, that I should not have thought, it worth communicat-
ing, if I had not been told that (he instruments made in London
for this purpose lose their effect alter a few experiments.

Having removed the electrical apparatus from a Volta's lamp,
I placed a fragment of precipitated platink between two pieces
of watch spring, which are inserted into a cork fitting into a
small test tube as a cap. The distance of the platina from the

366 Mr. Brooke on Nuttallite. [May,

jet is about three-quarters of an inch, and a small wax taper is
fixed about half an inch beyond the platina.

The only precautions I have found necessary are, to replace
the cap immediately after each experiment, and to employ a
pressure upon the hydrogen of not less than five or six inches of
water. With a pressure of nine inches I have never failed in
producing the same effect from platina foil of -g-^- inch in
thickness, by using the precaution of keeping it in a closed
tube ; but when the thickness of the platina foil was -s-jVo* **•
required to be previously raised to nearly a red heat.

The experiment of the aphlogistic lamp may be exhibited to
great advantage by employing either precipitated platina or
platina foil suspended over the wick, instead of wire, as origi-
nally proposed. I am, dear Sir, truly yours,

J. Cumming.

P. S. By the kindness of our late Woodwardian Professor,
Mr. Hailstone, I have been favoured with some fragments of
titanium formed in iron slag, for the purpose of ascertaining its
place in the thermoelectric series ; which I find to be between
platina and silver, but have not as yet been able to determine
its precise situation with respect to the intermediate metals.

Article X.

On the Nuttallite, a new Mineral from Bolton, in Massachusetts.
By H. J. Brooke, Esq. FRS. &c.

(To the Editor of the Annals of Philosophy.)

DEAR SIR, April 20, 1824.

I have received from my friend Mr. Heuland a small specimen
of a mineral from Bolton, in Massachusetts, brought by Mr.
Nuttall to this country.

It had been named elaeolite, I suppose from its exhibiting a
play of light resembling that which is frequently seen in the
fettstein from Norway, and from its colour generally approaching
to that of the same mineral ; some fragments are, however,
nearly transparent and colourless. On examining the crystals,
which are imbedded in carbonate of lime, I find that they differ
both in cleavage and lustre from elaeolite, and that they are
much softer. They present the form of a right square prism
which may be regarded as the primary, with cleavages parallel
to its lateral planes. The lateral edges of this prism are replaced
by single planes, but the terminal planes are imperfect.

It is softer and much more glassy in its fracture than scapolite,

1824.] Dr. Berger's reply to Mr. Henslow. 367

for which, on account of its form, it might be mistaken, and
does not resemble any other mineral with which 1 am acquainted,
I have, therefore, named it Nuttallite, out of respect to the
gentleman who brought it to this country.

I hope at some future time to be enabled to describe it
more fully than I do from the minute crystals my specimen
contains.

Article XI.

Reply to Mr. Henslow's Observations on Dr. Berger's Account
of the Isle of Man. By J. F. Berger, MD.

(To the Editor of the Annals of Philosophy.)

SIR, Geneva, March 9, 1824.

Being engaged a short time since in some researches at the
public library of our city, I there met with the second part of the
fifth volume of the Transactions of the Geological Society of
London, the 27th article of which is entitled Supplementary
Observations to Dr. Berger's Account of the Isle of Man, by
J. S. Henslow, Esq. MGS. Unless I deceive myself it is the
business of him whom a criticism especially concerns, either to
profit by a reasonable and impartial criticism, or to animadvert
upon that which is not true, or dictated by the malignity of
envy.

The charge of having published a memoir from " loose memo-
randa,* is of so grave a nature, that Mr. Henslow ought to have
satisfied himself that it was well founded, or to have named the
persons from whom he received the information.f If Mr. H. had
taken the trouble to write to me upon this subject, I should have
replied, without in any way discouraging a criticism upon a pub-
lished memoir, that I had remained in the Isle of Man only from
the 1st of June until the 8th of July, 1811, and that it was on my
return from Ireland to London, in the beginning of 1813, that I
drew up the memoir published in the second volume of the Trans-
actions of the Geological Society, from notes actually made on the
spot ; and with the exception of Mr. Thomas Webster, Draughts-
man to the Society, I have no recollection that any member of
the Society ever saw these notes, for no opportunity of showing

" After having finished, ah much as depended upon myself, the geological examination
of thus Isle, fearing that my notes originally written in pencil, might be obliterated, it
occurred to mc to fix the plumbago upon the paper by a process well known to artists,
by moistening witli a sponge dipped in milk, the leaves of my book, which I unsewed,
and which from that time were louse sheds.

t Nc quid falsi audcal, ne quid veri nun audcut dkerc.

368 Dr. Berger's reply to Mr. Henslow. [MAY,

them presented itself. Mr. Webster obligingly lent me his
assistance in preparing the map and sections which accompany
my memoir,* but it is true that I did not consult him on subjects
which were not in his department.

It will be readily conceived that I had not the means of ascer-
taining whether the southern part of the chain of mountains is
placed in my map of the Isle of Man two or three miles too far
to the east, according to the opinion of Mr. Henslow (p. 483;.
This fault may exist, and probably is not the only one. I
regarded this document merely as a geological map, without
absurdly pretending to dedicate it to geographical engineers.^
I will only add, that, in my opinion, it is better as a topographi-
cal map of the mountainous part than those of my predecessors,
and that in publishing his own, Mr. H. has not rendered mine
useless, or superfluous.

I must confess 1 was surprised on reading (p. 482), that I had
omitted to mention several formations of rocks, being persuaded
that I had inspected them all, with greater or less brevity, except
those which are volcanic. I was fearful that some unquestion-
able trace of volcanos, either extinct, or in activity, had escaped
me, but I was not long in recovering from this apprehension,
by observing that my critic, and 1 do not attach the same idea,
to what is called a formation of rocks, and that Mr. H. applies
this term to objects which are of very secondary importance.^:

Mr. Henslow has found granite in situ in other places than
those which I have mentioned, and he has also traced its course
further in another direction than I have done. But did this
require for its narration more than three quarto pages ? The rock
called greuwacke,\ by those who adopt the principles of Werner,
is remarkable in this respect, that being composed of the remains
of ancient rocks, it expresses a formation of modern date, which
is supposed to have occurred by deposition, rather than by che-

* I have publicly acknowledged my obligation to him.

+ I had then only a simple pocket compass to make use of in going successively
from one mountain to another.

\ I am of opinion that in Geognosy the term Formation may be defined to be an
assemblage of certain rocks or mineral matters, which appear, according to their
geognostic relations of position, to be contemporaneous or nearly so. I am at present
acquainted only with the following :

1. Formation of Primitive Rocks. -

2. Transition Rocks.

3. Secondary Rocks (Floetz).

4. - i — Alluvial Rocks, or matter.

5. Volcanos.

I leave it to those who are more capable than I am, to determine whether what is
called the fresh-water limestone should be added to the most recent members of the
third formation, or whether it is actually a distinct formation between the third and
fourth.

§ Professor Jameson, by translating the first part of the German name into Eng-
lish, has rendered the pronunciation less harsh.

1824.J Dr. Berger's Reply to Mr. Henslow. 369

mical action. Although it is not always easy to distinguish the
schistose variety of this rock from argillaceous schistus, it may,
however, be effected either by a glass which magnifies consider-
ably, or by the blowpipe, which converts the greywacke into
a frit only, while the argillaceous schistus fuses ; this is
undoubtedly the effect of the fluxes naturally mixed with it. I
believe also that the mean specific gravity of this rock is rather
greater than that of schistose greywacke. The natural decompo-
sition of the latter produces a sterile sandy soil, but little suited to
vegetation, on account of the readiness with which water passes
through it ; while, on the contrary, it is retained by the plastic
property of the decomposed argillaceous schistus. Lastly, the
relative positions materially assist the travelling geologist. I
had carefully weighed all these distinctive characters at the time
of arranging my memoir on the Isle of Man. I have allotted a
considerable space to this transition rock, and I find no reason
in the supplementary observations of Mr. Henslow, which induces
me to alter my opinion in this respect.

Mr. H. gives so indistinct an idea of the rock which charac-
terises what he terms the " quartzose district," that I shall take
no further notice of it.

I am pleased to believe that the circumscription of the lime-
stone country is more correctly traced in Mr. Henslow's map
than in mine ; but the difference is not assuredly very striking.
Without attaching too much value to a conjecture, 1 may inquire
of Mr. H. how he supposes the heterogeneous substances
which are found in amygdaloids have been formed there.*

I now arrive at my "great mistake" (p. 494), that of having
supposed that the whole extent of the isthmus of Langness was
composed of a conglomerate of quartz pebbles loosely attached
together. This error on my part may, perhaps, exist, and I
thank Mr. H. for having animadverted upon it; \ but I am much
disposed to believe, that the rock which, according to Mr. H.
forms the greater part of it, ought to be called schistose grey-
wacke, rather than argillaceous schistus.

Mr. Henslow mistakes when he makes me say (p. 495), that
all the interval between Scarlet and Poolvash is occupied by a
bed of amygdaloidal trap. I mention, on the contrary, the two
places in which 1 had observed this rock.]:

* It is well known that some of these substances, which are of a friable anil delicate
nature, often disappear from the paste in which they were inclosed, by the action of
atmospheric agents.

+ I owe it to truth to state, that not having completed the circuit of this isthmus, as
my companions may yet remember, 1 had some doubts, which were removed by iVIr.
Webster, as to colouring my map uniformly, as has actually been done. But I ought
at the same time to remark, that I do not say hi lite text of my memoir, thai tin- iBth-
inus of Langness is riitirrly Composed of this conglomerate. I confined myself lo gene-
ral statements, which are DOt incorrect. The small extent of tile isthmus of Langness,
compared to that of the whole isle, ought, perhaps, to disarm the extreme severity of
my critic.

t " Kaal-Farane and Cromwell's Walk, two places that separate Scarlet Point
from the entrance of Poolvash JJay, present an unstiatitied bed of amygdaloid, that OVei-
lies die limestone itself."

New Series, vol. VII. 2 B

370 Dr. Berger's Reply to Mr. Hensloic. [May,

Conformably to the general opinion, I have in my memoir
given the name of Curragh to the flat country only, situate to
the north of the group of mountains in the Isle, for I had never
heard that this name was applied to the tourbihes of the moun-
tainous country ; the flat country which I speak of having been
long used in agriculture, I thought it sufficient to state the
opinion of a respectable man (Bishop Wilson), relating to the
trees which they procured from it especially more than 20
years since. I have preferred to make known, by characters
which are, I think, unequivocal, the use and profit that the agri-
culturist now derives from the marl which is also met with in
this district below the sandy soil, to the subject, into the details
of which Mr. H. has entered with sufficient minuteness. The
discovery of elk bones and of earthy phosphate of iron in this soil
is unquestionably interesting, although it does not possess any
thing which is very extraordinary.

With respect to the shingly beach situate a little to the north of
the sandy hills which I have marked in my map by the name of
Balla-Chirrym Hills, Mr. Henslow exclaims against the annual
increase which I assign to it, from the assertion of several inha-
bitants of the Isle. But has he not frequently had occasion to re-
mark, how little the accuracy of expressions used in conversation
is observed; and was not the manner of stating this assertion,
which I evidenly considered as an exaggeration, sufficient to
undeceive any clear-sighted person ?*

I have now finished a hasty examination of a criticism, which
is undoubtedly rather prolix and inflated. I should have silently
profited by the truth which it may contain, if it had not been of
an injurious nature with respect to me, for it tends to induce the
belief that I have little respect for truth ; besides which, Mr.
Henslow's supplementary observations to my memoir have been
published in the Transactions of a Society of which I am myself
a member. Cuique Suum.

* " Some go so far as to say that the increase is no less than two yards in a year."
I will add that I wrote my memoir upon the Isle of Man in a foreign language, and
without the assistance of any person.

1824.] Analyses of Books. 371

Article XII.

Analyses of Books.

A Selection of the Geological Memoirs contained in the Annates
des Mines, together with, a Synoptical Table of Equivalent
Formations, and M. Brongniart's Table of the Classification of
Mixed Rocks. Translated, with Notes, by H. T. de la Beche,
Esq. FRS. FLS. MGS. &c. London, 1824. 8vo. pp. 335,
and 11 Plates.

When we compare the small space of time during which
geology has been pursued as a science of induction, with the
quantity of information that we now possess of the structure of
the globe, or at least of that portion of it which is open to the
cognizance of man, we cannot fail to perceive, that the progress
of geology in the mighty march of knowledge witnessed by the
present century and the latter part of the preceding one, has
been fully commensurate with that of the kindred sciences of
Mineralogy and Chemistry. The principles of geological
science have been, to a great extent, distinctly established, and
are now applying to the examination of the physical structure of
almost every part of the earth. The geological features of south-
ern Europe, and of the British Isles, have been most diligently
investigated, — though with respect to these alone much yet
remains to be accomplished — and the knowledge thus gained
has been employed with the greatest advantage, in the compa-
rison of them with those of other countries. The results have
been given to the world in a numerous series of memoirs, in
almost every language of Europe, but principally in French and
in German. From those in the former language, published in
the Annales des Mines, a work conducted by the General
Council of Mines at Paris, Mr. de la Beche has in this volume
performed an acceptable service to British geologists, by select-
ing, with some abbreviation, a series of the more important
papers. His own eminence as a geologist is a sufficient gua-
rantee for the quality of the work: and we shall therefore confine
ourselves to a brief analysis of its contents ; appending to this,
however, his translation of M. Brongniart's " Notice on the
Magnesite of the Paris Basin," or which we purposed to have
given an abstract in the Annals, some time since.* The work
commences with Mr. de la Beche's very useful " Synoptical
Table of Equivalent Formations," giving the names of the
various rocks in English, French, and German, and to which
are subjoined the synonymes of certain individual geologists

" See Annalt, N. s. vi.l.iv. |>. 88!».
2b2

372 Analyses of Books. [May,

where these differ from the terms in general acceptation. Mr.
de la Beche, we observe, gives the " new red conglomerate,"
as the equivalent formation to the " rothe-todte-liegende,"
placing the latter between the alpenkalkstein (magnesian lime-
stone) and the porphyr gebirge of Keferstein (new red porphyry,
porphyre du gres rouge), which is succeeded. by the coal mea-
sures : and in the preface we find the following observation on
this subject : — " With respect to the identity of the new red
conglomerate with the rothe todte liegende of Germany, it may
perhaps be right to mention, as discussions have lately taken

Slace on this subject between the Rev. W. D. Conybeare and
Ir. Weaver, that the conglomerate usually termed new red con-
glomerate, in the neighbourhood of Exeter and Teignmouth,
seems closely to resemble the rothe todte liegende, as has been
already stated by Prof. Buckland ; the magnesian limestone is
unfortunately wanting in that country, or at least has not been
described, though traces of it are mentioned by Mr. Conybeare
(Outlines of the Geology of England and Wales, p. 308) at Samp-
ford Peverell, in Devonshire, for beneath that rock the German
rothe todte liegende is always described as occurring."

The next article is M. Brongniart's Table of the Classification
of the Mixed Rocks, from the Journal des Mines, which we are
glad to see in an English dress ; for, with the exception of Dr.
Macculloch's, we think it the only useful arrangement of those
important substances that has yet been devised : though we are
also of opinion that a combination of the two might be effected,
with some additions, perhaps, from M. de Leonhard's new
" Charackteristik der Felsarten," which would be preferable to
either. We would likewise suggest to some mineralogical geo-
logist the propriety of determining a series of the British rocks
according to the classification of M. Brongniart, and of publish-
ing a table of their localities.

The memoirs from the Annales des Mines then succeed, and
are as follows : — Geological Sketch of the Coal District of
Saint-Etienne ; by M. Beauier (with a geological map).
Memoir on the Geographical Extent of the Formation of the
Environs of Paris; by M. d'Omalius d'Halloy (with a geological
map). Extract of a Memoir on the Possibility of causing Fresh-
Water Molluscte to live in Salt-Water, and Marine Molluscae in
Fresh-Water, with geological Applications; by M. Beudant.
On Gabbro ; by M. Von Buch. Memoir on the Mountain of
Rock Salt at Cardona, in Spain ; by M. P. Louis Cordier.
Observations on the Formations of Ancient Gypsum occurring
in the Alps, particularly on those considered as primitive ; pre-
ceded by new Facts relative to the Transition Rocks of that
Chain ; by M. Brochant de Villiers (with a lithographic map,
sections, &c.) Geological Sketch of the Thuringerwald ; and
on some Basaltic Mountains of Hesse andThuringia ; by M. de
Hoff. Report on the Tin of Periac (dep. of the Loire Infcre.) ; by

1824.] De la Beche's Selection of Geological Memoirs. 373

Messrs. Junker and Dufrenoy. Considerations on the Place
that the Granite Rocks of Mont Blanc and other central Sum-
mits of the Alps ought to occupy in the Order of Anteriority of
the primitive Series ; by M. B. de Villiers. Memoir on the
Geology of the Environs of Lons-le-Saunier ; by M. Charbaurt.
On the relative Positions of the Serpentines (Ophiolites) Dial-
lage Rocks (Euphotides), Jasper, &c. in some parts of the
Apennines ; by Alex. Brongniart (with lithographic sections,
&c.)- On Fossil Vegetables traversing the Beds of the Coal
Measures ; by the Same (with a lithographic print of the Coal
Mine of Treu'il, near St. Etienne, showing the Stems of large
Vegetables). Notice on the Coal Mines of the Basin of the
Aveyron; by M. du Bosc. Notice on the Geology of the
Western Part of the Palatinate ; by M. de Bonnard. On the
Zoological Characters of Formations, with the Applications of
these Characters to the Determination of some Rocks of the
Chalk Formation ; by A. Brongniart (with a lithographic print
of organic remains, and another of the Montagne des Fis).
Notice on the Hartz ; by M. de Bonnard. On the Calcareo-
trappean Formations of the southern Foot of the Lombard Alps ;
by A. Brongniart. Notice on the Magnesite of the Paris Basin,
and of the Position of this Rock in other Places ; by the Same
(with a plate of sections). Observations on a Sketch of a
Geological Map of France, the Pays-Bas, and neighbouring
Countries ; by M. d'Omalius d'Halloy (with the map). On the
Geology of the Environs of St. Leger sur Dheune (dep. of the
Saone and Loire) ; by M. Levallois.

In his table of Equivalent Formations, Mr. de la Beche has
inserted the muschelkalk and quadersandstein of Germany as
separate formations, in order to show the opinions at present
entertained on the subject by some continental geologists, who
consider the muschelkalk as distinct from our lias ; and conceiv-
ing it to be of some importance to determine if we are or are not
to add two new formations to our secondary rocks, he has, in an
Appendix, subjoined to the above memoirs, the description of
the muschelkalk and quadersandstein given by M.Humboldt in
his " Essai sur les Gisement des Roches," and that inserted by
Dr. Bout: in his Memoir on Germany published in the Journal de
Physique.

We proceed to extract M. Brongniart's notice on Magnesite:
" The distribution of the rocks and minerals entering into the
composition of the crust of the globe, may be regarded in differ-
ent points of view, and the different kinds of relations subsisting
between these: bodies successively examined.

" Sometimes we take a formation composed of different kinds
of rocks, whose epoch of formation is well determined in one
place, and we follow it in other parts of the globe, to see if it
preserves the same position, and to study the mineralogical mo-
difications it experiences : this point of view is principally geo-
logical and secondari/i/ mineralogical. Sometimes we study a

374 Analyses of Books. [May,

simple or mixed rock, of a certain nature, and following it in
different places or in the different formations in which it occurs,
we examine at what epochs it has been deposited on the surface
of the globe, what are the minerals and rocks with which it is
associated, and what peculiarities it presents in each of these
epochs. This point of view is principally mineralogical, and
secondarUif geological : it is as productive as the first in general
results, and consequently as proper as it to discover the laws
which have presided at the structure of the earth, and at the
formation of the minerals that enter into its composition.

" It is under this last point of view that I shall consider the
mineral which I have mentioned by the name Magnesite.

" The following are the minerals to which I give this name.
I distinguish them in two principal series, which may one day
l)c separated into two species when we shall have observed
sufficiently essential characters to establish this distinction.

" 1. Plastic magnesite (magnesite plastique), composed of
magnesia, silex, and water, without carbonic acid.

" I here comprise the magnesite, so improperly named ecume
de Mer, that of the environs of Madrid, that of the environs of
Paris, that of Salinelle, department of the Gard, &c.

" Serpentine might, from its composition, almost be referred
to tiiis species ; but it is distinguished from it by its mineralogi-
cal characters.

<: 2. Effervescent magnesite (magnesite effervescente), essen-
tially composed of magnesia and carbonic acid, sometimes asso-
ciated with very variable proportions of silex and water.

" We may refer to this division the magnesite of Hroubschitz,
in Moravia ; those of Piedmont, of the Isle of Elba, of Baumgar-
ten in Silesia, of Styria, 8cc.

" Having made known, as far as it appears necessary, the
minerals 1 include under this name, I shall now describe the
position of the magnesite of the Paris basin, and present the
union of a few facts and observations in order to complete the
geognostic history of these minerals, the principal object of this
notice.

Parisian Magnesite.

** I first observed the presence of magnesite in rather exten-
sive beds at Coulommiers, 12 leagues to the E. of Paris, and
afterwards quite close to the latter town : I shall describe this
variety and the circumstances of its position with some detail,
as I shall afterwards employ it as a type of comparison with the
same mineral, found in other positions and in other places.*

" The magnesite of Coulommiers, in the purest specimens, for
it is often mixed with other things, possess the following cha-
racters : — •

* I am indebted to M. Merimee for the knowledge of this magnesite. He was
struck with the soapy unctuosity of a stone which he found at Coulommiers, and hav-
ing brought it to me, he put me in the way of discovering this mineral in the Paris
basin.

1824.] De la Beche's Selection of Geological Memoirs. 375

" Its masses are soft, smooth to the touch without being
unctuous ; its powder is rather hard.

" It easily absorbs water and swells out considerably, becomes
slightly translucent, and forms a short soft paste, resembling

jelly.

" It does not effervesce with acids. ,

" Exposed to the action of a porcelain furnace (at 140° of
Wedgevvood), it hardens, exfoliates a little, but does not suffer
any other alteration ; it does not show the slightest trace of
fusion, either in its thin pieces or on the surface ; it however
becomes rough to the touch, and hard enough to scratch steel.

" M. Berthier has analyzed this magnesite, chosen from the
purest masses, and has found the following ingredients : —

Magnesia 24-0

Silex 54-0

Water 20-0

Alumine 01-4

99-4

" The magnesite of Coulommiers occurs in masses, which,
by their schistose structure and thinness, show they belong
to thin beds.

" Its colour is whitish, most commonly pale grey ; it has often
a roseate tint, but it loses that and its grey colour in the fire.
It is associated with brownish and reddish chert (silex corne) of
a very scaly fracture ; it is intimately united with it, and pene-
trates into all its cavities, and even into its mass ; it is also very
frequently associated with marly limestone, and then effervesces
and becomes partly fusible.

" This magnesite occurs in thin beds, interposed between beds
of marly limestone and calcareous marl, near Coulommiers, on
the right of the road, entering the town on the Paris side, in a
small hill having a north and south direction, and which having
been cut to form a canal, exposes its interior structure and the
following series of rocks, beginning with the uppermost.

" L A bed, composed of siliceous limestone, the middle of
which is of white and cellular chert (silex corne), and the com-
pact limestone mass filled by small shells scarcely determinable,
and by larger shells, such as Limneus longiscatus, cyclostoma
mumia, &c.

" 2. This bed rests on a bed of very irregular thickness, of a
greyish fissile earth, resembling clayey marl, and which has been
recognised to be an impure magnesite, i. e. mixed with calcare-
ous mail.

" 3. Then follows a bed of soft and friable calcareous marl,
containing another small bed of magnesite.

" 4. A bed of calcareous marl without silex, beneath which is
another small bed of brown impure magnesite.

376 Analyses of Boohs. [May,

"5. A thick bed of white calcareous marl subdivided into
many strata by marl beds, and by a bed of zoned chert (silex
corne zonaire), almost jaspic, without either shells or magnesite.

" 6. A bed about two decimetres thick, composed of brown
chert (silex corne) in irregular nodules, but principally flattened.
These are the nodules that are enveloped and even penetrated
by the Parisian magnesite of an isabella roseate grey colour.
It is sometimes very pure, does not effervesce with acids, and is
absolutely infusible in the heat of a porcelain furnace. It is
sometimes slightly translucent.

" 7. These cherts (silex) are placed on a bed of hard calcare-
ous marl in nearly round nodules, and containing cyclostoma
mumia.

" 8. Beneath is a thick bed of white calcareous marl, friable
or only splintery, and containing neither chert (silex) nor shells.

" The total thickness of the beds composing this hill is nine
metres (about 29 feet).

" As this succession of beds and rocks is isolated, as no
other formation is seen above it, and as we do not know that on
which it rests, we can at most suspect its position by a compa-
rison of these rocks with those that resemble them in the Paris
basin ; but this is a presumption difficult to prove without the
presence of the organic remains found in it ; now this character,
which is so useful in establishing analogies between formations
far distant from each other, possesses all its value when it is
required to determine the position of one formation with respect
to the others in the same basin ; it may then be here employed
with perfect safety, and geologists who admit these rules of
determination, and who have seen the cyclostoma mumia and
Linmeus longiscatus cited, have immediately lecognized the
position of the formation containing the magnesite of Coulom-
miers. These shells are not marine, one of them is evidently a
fresh water shell, consequently the magnesite belongs to a fresh
water formation, and the two species of shells 1 have just men-
tioned, having as yet been only found in the middle fresh water
formation, in that situated between the two marine formations of
the Paris basin, we should refer the magnesite of Coulommiers
to that fresh water formation ; it forms part, as we have else-
where* shown, of that which we have named siliceous lime-
stone. The hard calcareous marls, and the silex that accompa-
nies the magnesite, remind us of the siliceous and calcareous
characters of this deposit, and complete all the analogies.

" The magnesite having shown itself in a very distinct manner,
both as to its purity and quantity in the siliceous limestone of
Coulommiers, the rules of geology teach us that we should find
it elsewhere, by searching for it in this formation ; this has in
fact happened. Proceeding towards Paris, and at about two

* Description Oeologiquc des Environs de Paris, 1 822, p. 38, and 203.

] 824.] Dc la Becke's Selection of Geological Memoirs. 377

leagues from Coulommiers, we observe near Crecy the same
rock with the same mineralogical circumstances ; i. e. the lime-
stone so compact that it resembles the fine compact limestone
of the Jura, the chert (silex), the clayey marls, the magnesite,
but less pure, and the same fresh water shells.

" The short distance of these two places rendered these
resemblances very presumable ; but transporting ourselves to
St. Ouen, close to Paris, on the bank of the Seine and at the
foot of Montmartre, we find the magnesite in a formation alto-
gether similar to that of Coulommiers ; the same limestone, the
same chert (silex), the same shells occur there ; the position of
the rock beneath the gypsum is there well determined. The
magnesite is however less pure here and less apparent;
traces of it only occur ; these traces had long since been
observed. M. A rmet had remarked the presence of magnesite
in the marls of Montmartre ; M. Bayen had observed, more
than thirty years since, and had shown me that the menilite con-
tained it. Now this belongs to the fresh water formation
beneath the gypsum ; it is probable that we should find this
mineral either in minute quantities, or in small masses, in all the
siliceous limestone rocks of this same formation, such as those
of Champigny, Orleans, Septeuil, &c. I have recognised it in
a greyish clayey marl which accompanies a silex resinite of the
environs of Mans, consequently at more than 40 leagues to the
west of Paris, and 50 leagues from the first place in which I have
mentioned it.

" Geological Circumstances of the Magnesite of different Places,
compared with those of the Parisian Magnesite.

" We shall find this rock still further distant, in a basin se-
parated from ours not only by a distance of more than 120
leagues, but by chains of mountains whose structure and nature
are altogether foreign to those which surround our basin ; now,
it is remarkable, that we find the magnesite with all the circum-
stances which accompany it in that part of the Paris basin
where it is most pure.

" Magnesite has long since been observed at Salinelle, near
Sommieres, in the department of the Gard, between Alais and
Montpellier ; but its position has only been determined a few
years since, by the description M. Marcel de Serre has published
of it.

" It is therefore solely to the remarkable analogy of this posi-
tion with that of Coulommiers that I wish to call the attention
of naturalist*. The magnesite of Salinelle is schistose like that
of Coulommiers ; it possesses the same colour, approaching grey
with a roseate tint, with the same tenacity; it absorbs water in
the same manner ; it is composed of the same ingredients, i. e.
20 parts of magnesia instead of 24, 51 of silex instead of 54,
and 22 of water instead of 20. It will be acknowledged that it

378 Analyses of Books. [May,

is difficult to meet with more resemblance between uncrystallized
minerals, which occur at more than 100 leagues from each other,
and if the niineralogical species cannot be here determined by
the form, it is sufficiently so by the composition ; the analogies
drawn from its associated minerals, and its position, are the
same ; it is mixed with nodules of chertz (silex corne) which
resemble our menilite ; it is accompanied and covered by marly
limestone containing fresh water shells, consequently it belongs,
with that of the Paris basin, to a calcareo-siliceous fresh water
formation.

" But magnesite, i. e. this stone essentially composed of mag-
nesia, silex, and water, occurs in many other places dispersed
over the surface of Europe, and consequently placed at great
distances from each other. Sometimes we are acquainted with
its mode of occurrence, and then we know that it is very differ-
ent from that I have above described ; sometimes we are igno-
rant of it, or at least we do but presume it ; but in all these
places and in all these positions we shall see the magnesite to
occur accompanied by the Same niineralogical characters and
the same geological circumstances (circonstances geologiques);*
a consideration that must not be confounded with the geologi-
cal position (gisement).

" The magnesite of Vallecas near Madrid is already known ;
for in 1807 I described, in my Traite de Mineralogie (t. ii. p.
492), its nature and properties, from the information obtained by
the specimens received from Messrs. Sureda, Dumeril, and
Mieg, and of its position from the same specimens, and the
information of M. Link, who took it for a kind of clay ; a very
excusable error at that time. M. de Rivero has however studied
the same places, and has sent me an ideal section of this rock,
with a detailed description which I shall transcribe almost
literally.

" ' The village of Vallecus is two leagues to the south of
Madrid ; it is situated lower than the latter town ; an isolated
hill, named the hill of Vallecas, occurs near the village : before
we reach the top of this hill, we meet with small hillocks and
excavations which arise from the workings of the magnesite ;
the tour of this hill may be made in 20 minutes. From observ-
ing the locality, an idea is conceived of a gypsum basin on
which the magnesian rock rests.

" ' If we observe the structure of the hill, we observe, com-
mencing at the lowest part, gypsum with clay, which belongs to
the saliferous formations')- of Villarubia : this gypsum extends
from the walls of Madrid to the junction of the river Javama

* " I have literally translated M. Brongniart's expression, though I should not have
used it myself in the same? sense ; M. Brongniart seems only to imply that it is con-
stantly associated with certain minerals, without any reference whatever to its geological
or relative position. — (Trans.)"

■t " New red or saliferous sandstone. — (Trans.)"

1824.] De la Heche's Selection of Geological Memoirs. 379

with the Manzanares ; it is very distinctly seen near the hermi-
tage of Notre Dame de la Torre, 150 metres (492 feet) to the
west of the hill of Vallecas, and near the canal of Madrid ; there
then follows a bed of reddish clay with nodules of flint (silex
pyromaque). Though the magnesite has not been observed
immediately on the clay, yet M. de Rivero conceives that it
rests upon it, because ascending towards the hill, the magnesite
is found to follow ; and the flint nodules are the same as those
of the magnesite. The magnesite occurs in very thick beds,
coating flints which are disseminated through the beds : these
beds are cleft, and in the clefts we find asbestus (asbeste papy-
riforme), on which crystals of carbonate of lime are observed ;
they are also seen on the magnesite. This same deposit reap-
pears close to Madrid, it may be observed as we leave the bar-
riere by the Portello ; the flint is there disseminated in the same
manner. M. de Rivero has also met with it on the banks of the
river Manzanares, opposite the king's villa ; it has also been
found at Cabanas, nine leagues to Ihe north of Madrid : the
author, not having visited this last place, is unable to describe
its situation. A thin bed of greenish clay containing very little
magnesite is observed above the magnesite at Vallecas ; then
follows a reddish common opal (silex resinite) in beds of variable
thickness, very fragile, presenting a crust of manganese on some
parts of its surface ; this opal is worked for gun flints. A very
soft and nearly earthy magnesite is found above this fragile
opal.

" ' The different beds above noticed by M. de Rivero occur in
the hill of Vallecas. The top of this hill constitutes a platform,
on which are found many flints, and pieces of opal, with crystals
of carbonate of iron ; crystals of pseudo-morphous quartz have
moreover been observed, and have been taken for opal crystals.

"'Shells have never been met with in this formation. The
three upper beds appear on the banks on the Manzanares, as
we quit the gate leading to the Escurial.' "

" The author has above stated that magnesite is met with on
the banks of the river, and if we ascend towards the town, we
find beds of greenish and reddish clays of which bricks are made,
and above these clays an alluvial formation, composed of fine-
grained sand, and lastly vegetable earth on the surface.

" Thus the magnesite of Vallecas and Cabanas, near Madrid,
possesses the same tenacity, the same hardness, the same light-
in -s, the same superficial roseate tint, as those of Coulommiers
and Salinelle. It is equally composed of 23 parts of magnesia,
53 of silex, and 20 of water ; it is accompanied, like ours, by
chert (flint .'), which also passes into its mass, by common opal
(silex resinite), by chalcedony, by crystallized quart/., and calca-
reous spar altogether resembling those of our siliceous limestone.
It aflbrds, certainly, no organic remains; but wc know that these

380 Analyses of Books. [May,

remains are rare in the siliceous limestone of the Paris basin, of
which our magnesite forms a part; lastly, if it appears to differ
by its position on a saliferous gypsum, much more ancient than
our gypsum, and calcaire glossier, it is not covered by any rock
which appears more ancient than the latter, and it is like them
in horizontal beds.

" If from Spain we transport ourselves to Italy, to the foot of
the Piedmontese Alps, we shall find, at a short distance from
Turin, the serpentine hills of Castellamonte and Baldissero, tra-
versed in every direction by veins of magnesite which is tenacious
yet plastic, light, and with that roseate superficial tint which we
have noticed in the preceding magnesites. Its principal or fun-
damental and characteristic composition appears to be still the
same, i. e. of magnesia, silex, and water. Here however we have
carbonic acid, which seems to indicate a different chemical spe-
cies ; but its geological circumstances are still the same. I have
already noticed them in my memoir on the geological position
of the serpentines.

" The mineral no longer occurs in horizontal beds, or nodules
interposed in the beds, but in numerous veins, uniting in every
direction in the midst of the serpentine ; chert, common opal,
and jasper, presenting many varieties of texture and colours, are
constantly and intimately united with it, as at Coulommiers and
Salinelle. They have been formed even in the midst of the mag-
nesite. This circumstance of geological association is then
remarkably constant, even when the geological position has no
longer the same character, and it is here very different. It
appears to me well established, that this magnesite belongs to
the serpentine formation of the Apennines, consequently to
ancient rocks, nearly of the transition epoch.

" There are other examples of magnesites, but the circum-
stances of their geological position are less well known ; yet
both what is known, and their composition, still very well agree
with what we have stated of the preceding.

" Thus the plastic magnesite of Asia Minor, known by the
name of Ecume de Mer, has all the exterior characters of that of
Piedmont, and even that of Coulommiers, with a composition
that very slightly differs ; it has, like it, the roseate superficial
tint which also occurs in the magnesite of Houbricht in Moravia.
But in this, the carbonic acid, which is in some quantity, seems
to establish a mineralogical difference, the importance of which
is not yet well appreciated ; the presence of silex nodules which
pass into the mass, reminds us of an analogy in the geological
circumstances, which is rather remarkable."

Conclusions.

" We shall confine ourselves to these examples : they are
sufficient to prove the relations of formation which we wish to

1824.] De la Beche's Selection of Geological Memoirs. 381

establish between the magnesite of the Paris basin and those we
have just mentioned. The magnesite in all, whether it be or be
not combined with carbonic acid, contains water and silex; this
last substance does not occur only in chemical combination with
the magnesia, it also forms isolated masses, and whatever the
mineralogical differences may be that these varieties of quartz
present, not only is its difference all that is necessary to esta-
blish the geological resemblances which we desire should be
remarked ; but it may be said that these varieties follow without
interruption from the oldest to the newest magnesites, as the
following- table will show : —

D

Parisian magnesite ....■< Chert

Crystallized quartz

Several varieties of opal (silex resinite)

Magnesite of Salinelle. . Chert

( Crystallized quartz

Magnesite of Madrid . . \ C^ (silex corne)
6 j Chalcedony

C Several varieties of opal (silex resinite)

Maenesite of Moravia. . < ™,- u ± / , , ., :'•'!'%

b (_ White and green opal (silex resinite)

r Chert

Magnesite of Piedmont < v • .. -L . . ., .«. x

to j Varieties ot opal (silex resinite)

'Jasper

" Before geology had acquired in principles and facts the
precision to which it has now arrived, the presence of magne-
site in the Paris basin had no other result than that of adding a
mineral species to the list of those contained in our country ; but
this fact now possesses another interest : it has served to unite
observations which were, it may be said, isolated. It informs
us that the magnesite beds were deposited on the surface of the
globe at very different epochs, for some (those of Piedmont)
belong to the most ancient sediment rocks, and others (those of
Salinelle and Couloinmiers) to the newest sediment (tertiary)
rocks ; and yet we see these deposits accompanied by nearly the
same geological circumstances. Such a remarkable constancy in
the association of silex and magnesia, two bodies between which
there is no chemical analogy, will fix the attention of geologists,
and may perhaps contribute to show us the origin of these de-
posits, as the thermal springs of Italv deposing travertine have
pointed out that of the freshwater limestone. It is still apparently
iiom the bosom of the earth that the liquid arose which depo-
sited these rocks; for we find in certain thermal waters traces of
all the ingredients of their composition : the mass of water is at

382 Analyses of Books. [May,

present immense in comparison with the matters held in solu-
tion ; but these matters exist in it : they are deposited, as M.
Berthier has observed, at the waters of Vichy, St. Nectaire, Sec*
not only separately, but nearly in the same order, as the calca-
reous and magnesian formations. The first deposits, those
which are nearest the spring, this able chemist tells us, are also
those most charged with peroxide of iron and silex ; the lime-
stone, still ferruginous, then follows, and is the more pure and
more separated from these two substances, the more distant it
is from the point where the spring rises from earth; the carbon-
ate of magnesia is the last deposited.

" Without wishing to establish any real resemblance between
this succession and that of our rocks ; without wishing to repre-
sent that these rocks, certain beds of which show too clearly
the characters of mechanical aggregation for them to have been
formed by solution, have been deposited by the mineral waters
of the ancient world, we cannot avoid remarking that commenc-
ing with the chalk, we find a series of rocks, the nature and
succession of which are nearly the same as those which M.
Berthier has observed in the deposits from mineral waters.
Thus, first, a new formation, i. e. a new emission of dissolved
matter would appear to commence above the chalk, at first de-
positing silex and iron, represented, one by the beds of sand
and sandstone, and the other by the iron ore found so abund-
antly in the deposits of lignites and plastic clays which cover the
chalk ; secondly, the more or less compact limestone, accompa-
nied by iron and silex in the lower beds, and by silex in the
upper beds; the magnesite also accompanied by silex, which
still occurs in the lower gypsum beds ; this silex is partly
soluble in alkaline liquids, like that of the calcareous deposits
of certain mineral waters ; fourthly, the gypsum, the most
soluble substance of all those we have named, and which should
be the last deposited.

"We do not pretend to draw any other conclusion from
these different resemblances ; but it appeared to us right to
hazard them, if it were only to engage the attention of chemists
and geologists."

From this extract the reader will be able to judge of the man-
ner in which Mr. de la Beche has executed his task : and we
will conclude by recommending this work to all students of
geology ; to whom it will be highly useful, by enabling thein to
compare our own rocks with the similar formations on the conti-
nent which are described in it. B.

* Annates ile Chim. et de Physique, t. xix. p. 134.

1824.] Proceedings of Philosophical Societies. 383

Article XIII.

Proceedings of Philosophical Societies.

ROYAL SOCIETY.

March 4 (continued). — " Some further particulars of a case of
Pneuinato-thorax ; by J. Davy, MD. FRS."

Dr. Davy's hopes of the favourable termination of the case of
Pneumato-thorax, in which tapping was resorted to, as described
in the Appendix to his paper in the Philosophical Transactions
for 1823,* had proved fallacious ; — the patient had died ; and the
object of the present paper was briefly to detail the progress of
his disorder, and to give the examination of the air found in the
chest.

About a month after the date at which the history of
the case in the Philosophical Transactions terminates, hydro-
thorax supervened, and it was likewise found that air was
collected in the left cavity of the chest. A consultation being
held upon the case, a second operation was determined on. Dr.
Davy having experienced inconvenience in penetrating the in-
tercostal space, adopted the method of perforating a rib, men-
tioned by Hippocrates. Part of the fifth rib was accordingly
laid bare by the scalpel, then bored through by a carpenter's
auger, and the pleura penetrated by a trocar : about fourteen
ounces of clear fluid were obtained, containing albumen, and
a little sub-carbonate of soda, but no free carbonic acid ; the
succeeding portions, however, were more and more purulent,
and contained gas. The total quantity of fluid thus obtained
in the course of six weeks amounted to twenty pints. By means
of a trocar and bladder air was obtained from the aperture at
three several times ; and being examined by lime water and
phosphorus was found to consist of from 88 to 90 per cent, of
azote, 2 to 4 carbonic acid, and 3 to 5 oxygen. The patient
was at first much relieved by the operation, and seemed to be
recovering : but he eventually became worse, and died ; evi-
dently from the mere effects of the disorder.

On the examination of the body after death six ounces of
pus were found in the right pleura ; the right lung at first ap-
peared healthy, but upon minute examination a number of gra-
nular transparent tubercles were found disseminated through it.
The left lung was much condensed, so that it could not be
inflated by blowing with a pair of double bellows attached to
the trachea; it Communicated with the pleura by two small
openings. The heart was displaced, having been thrown to
the right side, obliquely on the spine. The body having been
opened in a bath, 170 cubic inches of gas were collected from
it, containing 16 per cent, of carbonic acid, and a little oxygen ;

* See our latt number, J>, 302.

384 Proceedings of Philosophical Societies. [May,

the residue being azote. This, Dr. Davy presumed, was atmo-
spheric air, deteriorated by respiration, and altered by the
absorption it had undergone while in the body. He had found
in the lungs, after death, in various cases, from 9 to 12 per cent,
of carbonic acid.

March 11. — A paper was read " On the Parallax of « Lyrse;"
by J. Brinkley, DD. FRS., &c. In this paper Dr. Brinkley
wholly opposes and controverts the statements of Mr. Pond re-
specting the subject of his paper, as given in the Phil. Trans,
for 1823, and noticed in the Annals for September last, p. 226.

March 18. — The Lord Bishop of Limerick was admitted a
Fellow of the Society ; and the name of the Earl of Orford was
ordered to be inserted in its printed lists.

A paper was read, entitled, " An Account of Experiments on
the Velocity of Sound, made in Holland. By Dr. G. A. Moll,
and Dr. A. Van Beck."

This paper commences with some observations on the New-
tonian formula for the velocity of sound, as modified by La-
place : and the authors then proceed to consider the effect of
the wind on that velocity ; which, in their own experiments,
they contrived to annihilate. These experiments were made on
the plains of Utrecht, at two stations 9964 feet distant from
each other ; and the velocity ascertained by determining the in-
terval between the flash and the report of guns by means of
clocks with conical pendulums, dividing twenty-four hours into
10,000,000 parts. The states of the barometer and thermo-
meter were noticed, and the humidity of the atmosphere deter-
mined by means of Daniell's hygrometer. The general result
is, that at the temperature of 32° the velocity of sound is
1089 - 7 feet per second. Various detailed tables of the experi-
ments and attendant circumstances are annexed to the paper.

March 25. — Major-General Sir John Malcom, GCB. was
admitted a Fellow of the Society ; and a paper was read, on the
Geological Distribution of Fossil Shells, in continuation of that
already published in the Phil. Trans.* by L. W. Dillwyn, Esq.
FRS.

A letter from Thomas Tredgold, Esq. Civil Engineer, to
Thomas Young, MD. For. Sec. RS. was likewise read :
it contained an account of a series of experiments on the elas-
ticity of steel at different degrees of temper ; describing the
apparatus with which they were made, and giving their various
results.

April 1. — The reading was commenced of " An Inquiry re-
specting the nature of the luminous power of some of the
Lampyrides; L. splendid 'ula or Glow-worm, L. Italioa, or Fire-
fly, and L. noctiluca : bv Tvveedie John Todd, MD. : commu-
nicated by Sir E. Home," VPRS."

April 8. — The reading of Dr. Todd's paper was resumed and

* See Anneckiot March, p. 177«

1824.] Proceedings of Philosophical Societies. 385

concluded. This paper commences with some general remarks'
on the various causes to which the luminosity of the lampyrides
has been ascribed ; the explanation of Macartney and Macaire,
that the light they emit is a simple product of vitality, being
considered as the true one. Dr. Todd then proceeds to a mi-
nute account of the apparent source and characters of the light
in the several animals ; describing the manner in which its
emission is affected by solar and other light, by heat, and by
certain chemical agents respectively. In the Lampyris splendi-
dula, the light is of a fine topaz yellow colour, with a tinge of
green, and is extremely vivid within the compass of a few
inches, but does not extend its brilliancy far around : within
that space the hour may be seen on a watch by its means. Tha
light of the Fire-fly is of a pale yellowish tint, with continual
flashes of vivid light : its variations are not connected with the
motions of the insect's wings, nor are they produced, as some
have affirmed, by the frequent intervention of a membrane.
This animal may be seen shining in full moon-light ; which is
not the case with its congeners. Irritants excite the luminous
power in all cases, and disorganizing substances destroy it.
Dr. Todd concludes that this power is solely an effect of vita-
lity, and that the light may be considered as animal light;
being analogous to animal heat, which arises from a power of
separating heat from its combinations with matter. He adopts
the hypothesis that its principal use is that of guiding the male
insects to the female, in the season of sexual congress : the
males always approach any light; and sometimes even the
shining females of other species, until they come very near
them. The fact that the larvae and even the ova possess a de-
gree of the luminous faculty, Dr. Todd does not consider as
militating against this explanation ; for various organs are par-
tially developed in the earlier stages of many animals, which
are only to be used by them when arrived at their perfect state.

A paper was also read, entitled, "A Comparison of the Baro-
metrical Measurement of Altitude with that by Trigonometry :
by Capt. Edward Sabine, FRS."

This paper contains the details of a comparative measure-
ment of the height of an hill at Spitzbergen in July last, by the
geometrical and barometrical methods : the instruments em-
ployed in both operations, and in the latter especially, had been
prepared with more than ordinary care, and the observations
were conducted with an attention to every circumstance which,
it was conceived, might influence the strictness of the compa-
rison, and sufficiently repeated to diminish at least the sliejit.
but unavoidable errors of observation. In the geometrical de-
termination, the base, exceeding 2000 feet, was measured on the
frozen surface of a bay at the foot of the hill, from whence a
polished copper cone fixed on the summit was visible : the ho-
rizontal and vertical angles were observed by a repeating circle ;

New Series, vol. vn. 2 c

386 Proceedings of Philosophical Societies. [May,

the height thus found was 1643 feet. The barometers were made
under the inspection of Mr. Daniell, with iron cisterns, as de-
scribed by Mr. Newman the maker, in a recent number of
the Quarterly Journal of the Royal Institution :* the one con-
veyed to the top of the hill was stationary there several days, and
repeated observations were made on each ; the mean height de-
duced from them was 1640 feet and a fraction, being less than
three feet in defect, when compared with the geometrical mea-
surement. The height is deduced from the barometrical obser-
vations by the method given by Mr. Daniell, in the Quarterly
Journal.

The near accordance of these results will, Capt. S. hopes, be sa-
tisfactory to those who are practically acquainted with the very
ready means which the barometer affords of measuring heights ;
the doubt which had been thrown on its equal applicability in the
northern regions, as in the temperate and tropical climates, by
the great differences which appeared in a similar comparison
made by Capt. Phipps and Dr. Irving, in the year 1773, and
which are now shown to have originated in error of some kind,
being wholly removed.

The Society, on account of the approaching festival, then
adjourned over two Thursdays, to meet again on the 29th of
April.

LINNEAN SOCIETY.

Dec. 16, 1823. — The reading of Mr. Murray's paper on the
Lampyris noctiluca was resumed and concluded ; and the fol-
lowing communications were read.

" Observations on some of the terrestrial Mollusca of the
West Indies; By the Rev. Lansdown Guilding, BA. FLS."
Among the species described in this paper were Helicina occi-
dentalis, corpore livido, dorso tentaculisque atris, oculis pro-
minulis. — In montibus sylvosis Sancti Vincentii ; Bulimus Ike-
mostomus, corpore olivaceo-nigro, corrugato : pede subtus pal-
lido : capite bifariam crenato. — In dumetis Antillarum ; Buli-
mulus stramineus ; and Pupa undulala.

" An account of some rare West Indian Crabs ; " by the same.
The Society then adjourned to January 21, 1824.

Jan. 21. — Among the presents received at this meeting was a
specimen of a new species of Cyprinus vivlparus, from Don
Vincente de Cervantes, Professor of Botany in the University
of Mexico.

A paper was read, " On a new species of the genus Gadus :
by Mr. Jonathan Couch of Polperro, in Cornwall." This dimi-
nutive species, called by fishermen the Mackarel Midge, is
only an inch and a quarter in length : its proportions are
nearly those of the Whiting.

The reading was commenced of a paper " On the Natural

* Mr. Newman's account of these instruments will be found in the last number of the
Annals.

1824.] Linneau Society. 387

Affinities that connect the Orders and Families of Birds : by
N. A. Vigors, Esq. MA. FLS. Communicated by the Zoological
Club of the Linnean Society."

Feb. 3. — Among the presents received at this meeting was a
Collection of Plants, made by Lieut. Col. Wright, of the Royal
Engineers ; during a journey through Circassia, Persia, and
Georgia.

A notice by Mr. John Hogg, of Norton, Durham, was read,
stating that a fine specimen of Falco chrysa'etos, or Golden
Eagle, was lately shot near the mouth of the Tees ; being the
fifth known to have been killed in England.

The reading of Mr. Vigors' extended paper was then resumed
and continued ; and it likewise occupied the attention of the
Society on Feb. 17 and March 2.

March 16. — The reading of Mr. Vigors' paper was also con-
tinued at this meeting ; and the following other communications
were read.

" Description of Erythrina Secundifiura. By Don Felix Avellar
Brotero, Emeritus Professor of Botany in the University of
Coimbra; For. Mem. of the Society."

"On the insect called Oistros by the ancient Greeks, and Asilus
by the Romans. By W. S. MacLeay, Esq. FLS. Communi-
cated by the Zoological Club of the Linnean Society." In this
paper, which may interest the lovers of classical antiquity as
well as of natural history, Mr. MacLeay has produced many
interesting proofs that the (Estrus of the ancients,

cui nomen Asilo

Romanian est, (Estron tiraii vertere vocantes." (VlltG. Geor. II.)

was not the insect to which the name is now given; but a
Tabanus. Olivier first observed that it was different from the
(Estrum of the moderns. Pliny uses the name Tabanusox the
MuojvJ/, which Aristotle says is nearly related to (Estrus, both
being atTrpoj-tfEvxcvrpa ; it cannot therefore be the modern (Estrus :
he also says that both are bloodsuckers, which agrees with the
Linnean Tabard, but is wholly inapplicable to the modern
(Estrus. As the insect is too well known for its name to have
been forgotten or misapplied, there can be little doubt that the.
Latin Tabauus, the Italian Tuba/to, Spanish Tavano, and French
Tuon are identical, which latter name Mouffet gives us the same
with the English Breese, Clegg and Clinger, mentioned by
Shakspeare, who, speaking of Cleopatra, says :

" The Brize upon her, like a cow in June,
Hoists sail and flics."

Some elucidation is also brought from Homer, and the Prome-
theus of iEschylus, and it is observed that Virgil describes the
Asilus or (Estrus as abundant and accrba sonans, whereas our
(Estrus bovis is a rare and silent insect. They were first con-
founded by Valisnieri, who has been followed by Martyn and
others. It is inferred that Aristotle did not even know the

' 2 c 2

388 Proceedings of Philosophical Societies. [May,

latter, from his assertion that no dipterous insect has a sting
behind.

April 6.— A letter was read, from the Rev. W. Win tear, of
HarlestOn, in Norfolk, stating that a Little Bustard had been
shot, in December last, at Little Clarton, in Essex. He con-
siders it to be a curious fact that this bird, an inhabitant of a
southern climate, should have been met with in this country, in
winter.

A description was likewise commenced, of a Collection of Arctic
Plants formed by Captain Sabine, during- a voyage to the Polar
Seas, in 1823 : by W. J. Hooker, LLD. FRS. &c. Communi-
cated by the Council of the Horticultural Society.

April 20. — Sir T. Gery Cullum, Bart. FLS. presented some
sections of Fir timber, pierced to a great depth by the Sirex ju-
vencus of Linnaeus ; together with specimens of the insect itself.
They were from the woods of Henham Hall, in Suffolk, the seat
of the Earl of Stradbroke, where two hundred Scotch Firs
have been destroyed by this insect ; being bored through and
through. The reading of Dr. Hooker's description of the
Arctic Plants collected by Capt. Sabine was continued.

A Catalogue of the Norfolk and Suffolk Birds, with remarks ;
by the Rev. Revett Shephard, AM. FLS., and the Rev. W.
Whitear, AM. FLS., was read in part, and the remainder post-
poned to a future meeting.

ZOOLOGICAL CLUB.

We have hitherto been prevented from noticing this useful
association. Its first meeting was held in the apartments of the
Linnean Society on the 29th of November last, the birth-day of
our celebrated countryman John Ray. The Club is composed
of members of the Society devoted to the study of zoology and
comparative anatomy, and has been organized with the view of
advancing the knowledge of those sciences, in all their branches,
under the sanction of the Society. This body will not have any
publications of its own, but will submit all original communica-
tions made to it to the Council of the Linnean Society, who will
decide upon them as upon all other communications.

Before the Zoological Club proceeded to the election of their
officers and the other business of the day, an admirable opening
address, explanatory of the views of the association, was deli-
vered by the Rev. W. Kirby, FR. and LS. who had been unani-
mously called to the chair.

The following members were then appointed to form the Com-
mittee and Officers for the management of the affairs of the Club
for the ensuing year : —

Joseph Sabine, Esq. Chairman ; J. F. Stephens, Esq. Treasu-
rer ; N. A. Vigors, Esq. Secretary: ReV. W. Kirby; A. H.
Haworth, Esq. ; Thomas Horsfield, MD. ; Thomas Bell, Esq. ;
E. T. Bennet, Esq. ; G. Milne, Esq.

1824.] Astronomical Society. 389

The meetings of the Zoological Club, at which all the mem-
bers of the Linnean Society are entitled to be present, are held
at the Society's apartments in Soho Square, at eight o'clock in
the evening, on the second and fourth Tuesdays of every month
throughout the year.

ASTRONOMICAL SOCIETY.

March 12.— The papers read at this meeting of the Society
were as follows :

A letter from Sir Thomas Brisbane, Governor of New South
Wales, to F. Baily, Esq. accompanied by Mr. Runiker's obser-
vations of the Summer Solstice 1823 at Paramatta; the results
of which are :

For the mean obliquity of the Ecliptic. 23° 27' 44-39"

For the latitude of the place of observation. ..33 48 42-61

Also the mean of twelve months' meteorological observations
made at Paramatta between May, 1822, and May, 1823.

A letter from Prof. Schumacher, of Altona, including Mr.
Hanson's computations of the elements of the comet of 1823,
1824, from observations made in the month of Jan. 1824.

Two letters from Mr. Taylor, jun. of the Royal Observatory,
Greenwich ; the first containing the elements of the same comet
as computed by himself from the Greenwich observations of
January, 1824, using Boscovich's method ; and the second, a
comparison of anticipatory ephemerides of the places of this
comet, from the elements computed severally by Schumacher,
Carlini, Dr. Brinkley, and himself, with the Greenwich obser-
vations.

On the Rectification of the Equatorial, by J. F. Littrow,
Director of the Imperial Observatory at Vienna. In this paper
the author directs his attention to those errors only which de-
pend upon the placing and use of the instrument, which the
observer himself must either be able to obviate or allow for ;
and he therefore enumerates the greater part of them, and
points out means for their rectification.

On the Utility and probable Accuracy of the Method of deter-
mining the Sun's Parallax, by observations on the planet Mars
near his opposition ; by Mr. Henry Atkinson, of Newcastle-
upon-Tyne. In this paper the author shows, that in a series of
observations on Mars, taken with good instruments used in
north and south latitudes, the probability of error is very small ;
and as the synodical revolution of Mars takes place in about
780 days, that planet will be 23 times in opposition before the
next transit of Venus on the 8th Dec. 1874. Hence he infers,
that if careful corresponding observations are made on each of
those 23 oppositions, the probable error would be reduced nearly
4-790 times. The author concludes his paper by describing

390 Proceedings of Philosophical Societies. [May,

what he regards as the best means of carrying this method into
effect.

A new annular Micrometer by Frauenhofer was submitted to
the inspection of the Meeting by Mr. Francis Baily. This
instrument is called by the artist the suspended circular
micrometer, from the circumstance of its appearing (in the
telescope) as if suspended in the heavens without any support.
It consists, in fact, of nothing more than a circular piece of
plate-glass about one-inch in diameter, in the centre of which a
circular hole is cut, of half an inch in diameter. To the inner
edge of this glass circle a narrow ring of steel is firmly and
securely fastened ; and, the whole being put in a lathe, the steel
ring is turned perfectly circular, and reduced to a very thin
edge, both at its exterior and its interior circumference. The
glass, with its steel circle, is then burnished into a brass ring or
cap, by means of which it may be placed, when required, in the
focus of the telescope.

The advantages attending this construction are, 1. The preser-
vation of the circular form of the ring, as it comes from the
lathe, without the risk of its being injured in attaching it to the
telescope in the usual manner : 2. In the use of steel instead of
brass, whereby a finer edge may be given to the circumferences :
3. In rejecting the metal arms by which these rings were for-
merly attached to the sides of the telescope, from the unequal
expansion of which (or any external violence given thereto) the
perfect form of the circle might be injured, without being imme-
diately detected : 4. In thus avoiding the obstructions which
those arms might, in some cases, by their position, occasion in
the observations of the passage of a star before it entered the
interior of the ring.

April 9. — At this meeting the following papers were read, viz. :

1. On the Elements of the Orbit of the Comet of 1823, com-
puted from Observations made at the Royal Observatory at
Greenwich, by Mr. W. Richardson, Assistant to the Astronomer
Royal. These elements were computed by Dr. Olber's method.
The paper likewise contained a comparison of his elements with
the Greenwich observations from Jan. 1 to Feb. 2, and in more
than half the observations, the results of the elements did not
differ from them so much as 2' in longitude, or so much as 1- in
latitude.

2. On the Corrections requisite for the Triangles which occur
in Geodesic Operations ; by Capt. G. Everest, of Bengal, Con-
ductor of the Trigonometrical Survey in India. This paper con-
tained the solution of two problems by formulae employed in
India since 1819, and which the author thinks preferable to
those given by M. Delambre for the same purpose. They
require the use merely of pocket logarithmic tables, with four
places of decimals, of which copious examples were given ; and

1824.] Geological Society. 391

the paper concluded by the application of these formulae to the
corrections of angles actually observed in the operations in
India.

3. On the Method of determining the Difference of Meridians
by the Culmination of the Moon ; by Francis Baily, Esq. FRS.
V . Pres. Ast. Soc. This paper was too long to permit its read-
ing to be completed at the present sitting ; and we shall, there-
fore, reserve our remarks upon it until it is concluded.

Several veiy valuable books were presented to the Society.

GEOLOGICAL SOCIETY.

Feb. 20. — A notice was read on the Megalosaurus, or great
Fossil Lizard of Stonesfield, near Oxford; by the Rev. W.
Buckland, FRS. FLS. President of the Geological Society, and
Prof, of Mineralogy and Geology in the University of Oxford,
&c. &c.

The author observes that he has been induced to lay before
the Society the accompanying representations of various portions
of the skeleton of the fossil animal discovered at Stonesfield, in
the hope that such persons as possess other parts of this extra-
ordinary reptile may also transmit to the Society such further
information as may lead to a more complete restoration of its
osteology. No two bones have yet been discovered in actual
contact with one another, excepting a series of the vertebra;.
From the analogies of the teeth they may be referred to the
order of the Sauricuis or Lizards. From the proportions of the
largest specimen of a fossil thigh bone, as compared with the
ordinary standard of the Lacerta?, it has been inferred that
the length of the animal exceeded forty feet, and its height
seven. Prof. Buckland has, therefore, assigned to it the name
of Megalosaurus. The various organic remains which are found
associated with this gigantic lizard form a very interesting and
remarkable assemblage. After enumerating these, the author
concludes with a description of the plates, and observations on
the anatomical structure of such parts of the Megalosaurus as
have hitherto been discovered.

MEDICO-BOTANICAL SOCIETY.

. Feb. 13. — Some observations were made on the Acacia Cate-
chu. A paper was also read, on a bark termed the Malambo
Bark, lately imported from America.

Feb. 27. — Some observations were read, on the alterations in
the Pharmacopoeia.

March 12. — A paper was read, entitled " Observations on the
Anthroxanthum Odoratum; by T. Rowcroft, Esq. his Majesty's
Consul General at Peru : communicated by Dr. Bree, President.

March 26. — Some observations were made on the Croton
Tiglium ; by Mr. Pope, of Oxford-street.

April 9. — A paper was read on the Resina Acaroides, by Mr
W.Bollaert.

392 Scientific Intelligence. [May,

Article XIV.

SCIENTIFIC INTELLIGENCE, AND NOTICES OF SUBJECTS
CONNECTED WITH SCIENCE.

I. The Logan Stone in Cornwall overturned.
(To the Editor of the Annals of Philosophy.)
DEAR SIR, Plymouth, April 18, 1824.

Your geological readers will hear with infinite regret, that the cele-
brated Logan Stone in Cornwall, which has for so long a period been
regarded as an object of great national interest and curiosity, and which
has been visited by persons from the remotest extremity of Europe,
has within the last few days been overturned by one of the Lieutenants
of his Majesty's navy, noiv commanding a revenue cutter, stationed
between the Lizard and Lands End, assisted by a party of his men.
The barbarous and wanton folly which could induce an officer bearing
his Majesty's commission to commit so unwarrantable an act, as to
remove a great national curiosity from a position in which it had stood
for ages, defying the hand of time, and affording to the enlightened
traveller an object of such singular interest, will, it is hoped, be visited
with the severest displeasure of the Admiralty. In a tour through
Cornwall in the summer of 1821, I was informed by a cottager who
lived near the spot, that an attempt was made by a party of seamen
some years before, to remove it, but without success. Cornwall, by
this wanton outrage, has lost one of its most interesting monuments.
I remain, dear Sir, yours very truly, G. W. Harvey.

II. The Rate of a Chronometer varies with the Density of the Medium

in which it is placed.

Mr. Harvey, ERSE, has lately discovered that the density of the
.medium in which a chronometer is placed, has a sensible influence on
its rate, in most cases producing an acceleration, when the density is
diminished, or a retardation, when the density is increased. In a i'ew
time-keepers he has found the reverse to take place, viz. a decrease of
rate from diminished density, and an increase from increased density ;
but the former appears to be the most general effect. Mr. Harvey
has proved this to be the case, by an extensive course of experiments,
and in which he has subjected many chronometers to pressures, from
half an inch of quicksilver to 75 inches; and in all cases has found,
that if a time-keeper gained by increasing the density, it lost by dimi-
nishing it, and vice versd. A difference of density denoted by an
inch of quicksilver, is sufficient to produce in many chronometers a
visible alteration of rate.

The following are a few of Mr. Harvey's results : —
A pocket chronometer which possessed a steady rate of + 1"*6
under the ordinary circumstances of the atmosphere, had its rate in-
creased to + G''-2, when the density of the air was diminished to a
quantity represented by 20 inches of quicksilver ; and on afterwards
placing it in air. of a density denoted by 10 inches of quicksilver, a far-
ther increase of its rate to 4- ll"-0 took place. On restoring the time-
keeper to the ordinary circumstances of the atmosphere, its rate re-
turned to + 2"-l.

1824.] Scientific Intelligence. 393

In another set of experiments with the same chronometer, Mr. H.
placed it in a condenser, under an atmospheric pressure of 45 inches,
when its rate changed to — 4"4 ; ani on increasing the density of the
air to a quantity denoted by 60 inches of mercury, the daily variation
farther declined to — 8" # 2.

In another remarkable experiment, Mr. Harvey found, that when the
rate of a chronometer was + 23""5, under a receiver having its air
exhausted to a quantity denoted by half an inch of mercury, the rate
was altered to — 17"'2, when the air was increased to a density cor-
responding to 75 inches of quicksilver ; the rate of the time-keeper,
under the ordinary circumstances of atmospheric pressure, being
+ **7.

Mr. H. has, we understand, drawn from it several important conclu-
sions. For example, that a chronometer constructed in London,
nearly on the level of the sea, would undergo an alteration of rate,
from difference of atmosphere alone, if transported to Geneva, to
Madrid, to Mexico, or any other place, situated much above the level
of the place where it was constructed.

III. Cheltenham Water.

Mr. Faraday has examined the water from the Orchard well at the
above place. A pint of this water yielded :

Carbonate of lime ; 1 "6

Sulphate of lime 145

magnesia 124

soda 3*7

Muriate of soda 97-0

129-2
Besides which the water contained a portion of carbonic acid ; and
a small quantity of peroxide of iron had settled at the bottom of the
bottle. By using two tests suggested by Dr. Wollaston, this water
was also found to contain small portions of nitric acid and potash.

On adding sulphuric acid to a portion of this water, in quantity
abundantly sufficient to decompose all the salts subject to its action,
and boiling the acidulated water in a flask with a leaf of gold for an
hour, the gold either in part or entirely disappeared, and a solution
was obtained which, when tested by protomuriate of tin, gave a deep
purple tint. Hence the presence of nitric acid, originally in the water,
was inferred, and that no mistake might occur, a solution made in
pure water of all the salts, except the nitrate found in the water,
was boiled with some of the same sulphuric acid, and tested by the
same muriate of tin ; but in this case no colour was afforded, nor any
gold dissolved.

The potash was ascertained to be present by evaporating a quantity
of the water until reduced to a small portion, filtering it, and then add-
ing muriate of platina in solution. Three pints of the water, evapo-
rated until about an ounce of fluid remained, gave an abundant pre-
cipitate of triple salts of potash and platina. In cases where small
quantities of the waters were tried, it was necessary to let the liquid
•fand an hour or two after applying the muriate of platina, but the
triple salt always ultimately appeared. — (Royal Institution Journal,
vol. xvii. p. 179.)

394 Scientific Intelligence. [May,

IV. Detonating Silver and Mercury.

Dr. Liebig has analyzed both these compounds, prepared by the
well-known process of causing alcohol to act upon the nitrates of the
respective metals. It appears from the experiments detailed that the
substance combined with the metallic bases is an acid, and separable
from them by means of the alkalies and metals, and they then form
the detonating compounds. To analyze detonating silver and mer-
cury, 100 parts of each were mixed with 400 parts of calcined magne-
sia, and heated in a retort, the products received were :

From detonating silver. From detonating mercury.

Carbonic acid 35 5 25*8

Ammonia 13-7 10

Water 7-2 52

Silver 41-0 Mercury 569

Loss 2-6 21

1000 1000

The above are the mean of four experiments ; these give as the ul-
timate elements.

Detonating silver. Detonating mercury.

Oxygen 3222 2339

Hydrogen 322 2-34

Azote 11-2S 8-23

Carbon 9 68 7*04

Silver 41'00 Mercury 56-90

The salts formed of the acid of these detonating compounds hav