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THE

PHILOSOPHICAL MAGAZINE:

COMPREHENDING

THE VARIOUS BRANCHES OF SCIENCE^ .
THE LIBERAL AND FINE ARTS,
AGRICULTURE, MANUFACTURES,

AND ,

COMMERCE.

BY ALEXANDER TILLOCH,

BONORAEY member of the KOYAL IRISH ACADEMY, &C. &€. &C.

" Nec aranearum sane textus Ideo melior quia ex se fila gignunt, nee nost«r
vilior quia ex alienis libamus ut apes." Just. Lips. Moiiit. FQlit. HIt^J, ran, i,

VOL. XXX.

For FEBRUARY, MARCH, APRIL, and MAY, 1808.

LOND ON:

PRINTED FOR JOHN MURRAY, FLEET STREET J AND

A. CONSTABLE AND CO. EDINBURGH :

And sold by Richardson; Cadell and Da vies; Longman, HuriTj

Rees, and Orme; Symonds; Vernor, Hood, and Sharpe;

Harding; Highley ; London: Bell and Bradfutk,

Edinburgh : Brash & Reid, and D. Niven, Glasgow:

and Gilbert and Hedges, Dublin.

Printed by Richard Taylor and Co, Shoe Lane.

CONTENTS

OF THE

THIRTIETPI VOLUME.

!• On the two Systems of Musical Temperament recom-
wended hy Earl Stanhope^ — Mr. Hawkes's System, C!^c.
By Mr. John Farey 3

II. Essay upon Machines in General. By M, Carnot,
Member of the French Institute, ^c. c^c, . . . . 8

III. Additional Memoir upon living and fossil Elephants,
ByM.CuviER 15

IV. Observations upon the Employment of M. Guyton-
MoRVEAu's Fumigations for preventing contagious In-
fection. By M. A. Hedouin, Physician . . . . 26

V. Letter from M. Guyton de Morveau upon the
Effects of Fumigations in Epidemics of Cattle, and for
the Destruction of putrid Miasmata 28

VI. Experiments upon the liquid Sulphur of Lampadius.
By Messrs. VAuauELiN and RoBiauET . . . . 30

VII. Letter from the Right Honourable Earl Stanhope,
relative to Dr. Callcott's Pamphlet on the Stanhope
Temperament 34

VIII. Upon the Decomposition of the Acetate of Barytes ly
means of Soda. By iV/. Darcet 36

IX. Upon the Preparation of pure Barytes. By M. Ro-
BiaUET 40

X. Observations upon the Combination of the fixed Oils
tvith the Oxides of Lead and the Alkalies. By M. Fremy,
Apothecary at Versailles 42

XI. Description of the Mountain Barometer, invented by Sir
Henry C. Englefield, Bart. F.R.S. and made by Mr,
Thomas Jones, of Mount Street, Berkley Square 46

XII. On E. V.'s Article " On the Means of gaining Power
in Mechanics " . . 62

XIII. Extract (f a Memoir upon the Products which result
from the Action of the Metatlic Muriates, the Oxy-mu-

riatic Acid, and the Acetic Acid, upon Alcohol. By
M. Thenard . . . . , , . . 64

XIV. Upon a peculiar Property in camphorated fVater.
By M. Cadet 66

XV. Letter from Gavin Lowe, Esq., on the Comet
of 1807 .. ,. 67

XVI. A Second Letter from E. V. on the Means of
gaining Power in Mechanics 70

XVII. On the Use of Sulphur as a Fermifuge. By Joseph
Hume, Esq., of Long- Acre, London 71

Voi. 30. No. 120. M(7?/'l80S. a XVIII. Ex-

CONTENTS.

XVIIT. Experiments for investigating (he Catise of the co^
loured CQJicentric Rings discovered ly Sir Isaac Nkwton,
between two Object-glasses laid upon one another, Bij
William Herschel, LLD. F.R.S. .. .. 72

XIX. Report of Surgical Cases in the City and Finslunj
Dispensaries for September 1807. By John Taun-
ton, Esq 90

XX. Proceedings of Learned Societies 91

XXI. Intelligence and Miscellaneous Articles . . . . 93

XXII. On Blasting Rocks and Tamping. By John Tay-
lor, Esq 97

XXIII. Extract of a Memoir vpon the Muriatic Ether ^ as
read at the French Institute, nth of February, I8O7.
By M. Thenard . . , . . . 101

XXIV. Memoirscf the late Et^asmusDarwin^ M.D. JO9

XXV. Experiments for investigating the Cause of the co-
loured concentric Rings, discovered by Sir Isaac Nkwton,
letweeu two Object- glasses laid upon one anothen-. By
William Herschf.l, LLD. F.R.S 1I5

XXVI. Observations upon Sulphureous Mineral Waters. By
M. Westrumb . , , , . . ] 291

XXVII. On the Preparation of' Calomel. By Mr. Joseph
Jewel . , , ^ 133

XXVIII. On the Contraction which takes place in Mercury
at low Temperatures by Abstraction of Heat ; — and on the
Ratio of Contraction between Mercury, Alcohol, Water y
and Silver, ^y John Biddle, Esq. of Birmingham 134

XXIX. Essay upon Machines in General. By M. Carnot,
Member of the French National Institute, '&'c. &c. 154

XXX. On Caloric, and the Heat evolved during Combustion,
By James ScHOLES, Esq., of Ma?ichestcr .. .. 138

XXXI. On the Cause of the diffei-ent apparent Magnitudes
of the same Objects seen under different Circumstances.
By Ez. Walker, Esq 163

XXXII. On the. Identity of S'llex and Oxygen. By Mr.
Hume, of Long- Acre, London ., 165

XXXIII On the public UtiUiy of Medical Insfitutio?is for
the Benefit of the Diseased Poor 1 71

XXXIV. On the constituent. Principles of Potash. By
^Mark Taero, Esq. of Beeston, near Shrewsbury 17*.«J

XXXV. On the best Means for preventing the fatal Con-
sequences that so frequently occur frorn the Dresses of

^ Females and Children taking fire 1 7 3

XXXVI. Letter from Sir H. C. Englefikld respecting
his Mountain Barometer .. , 176:

XXXVII. Reports of Surgical Cases in the City and Finsbury
Dispensaries, for October 180J -, with some Remarks on

the

CONTENTS,

the Dissection of the Brain of a Person who died insane*
% John Taunton, Esq 17^

XXXVIII. Report upon a Memoir read at the French Insti-
tute, bi/ M. Thenard, upon the Nitrous Ether, By Messrs.
GuYTON, Vauquelin, and Berthollet . . 1 77

XXXIX. Proceedings of Learned Societies . . . . 182
XL. Intelligence and Miscellaneous Articles .. .. 189
XLI. Experiments on the Influence of Time, as a chemical

Agent, in depriving an elastic Fluid of its Elasticity/.
In a Letter f'lom M. BioT to M, Berthollet . . J93

XLtl. Experiments for investigating the Cause of the cO'
Loured co7icentric Rings, discovered hy Sir Isaac Newton,
between two Objert- glasses laid upon one another. By
William Herschel, LLD. F.RS 295

XLIIl. Essay upon Machines in General, By M. Car not.
Member of the French National Institute, &c. &c. 207

XLI V. Processes employed for finishing the Inside of the
Palaces of the Native Princes in some Parts of the East
Indies 221

XLV. Notice upon the Analyses of the Chr ornate of Iron^
and upon the Fariety of the Epidote called Zoysite. By
M. Hauy ,, ..* .. 223

XLV'L On drying Articles of Manufacture, and heating
Buildivgs, by Steam, By R. Buchannan^ Esq., Civii
Engineer^ Glasgow .. .• .. 225

XLV J I. On the ceconomical Uses to which the Leaves and
Pruning s of Fines may be applied in this Country 22(5

XLVllI. Observations on the Nature of the new celestial
Body discovered by Dr. Olbers ; and of the Comet which
was expected to appear last January in its Return from the
Sun. By William Hebschel, LL.D. F.R.S. 227

XLIX. An Account of a remarkable Shower of Meteoric
Stones, at JFeston in America. By Mr: Silliman,
Professor of Cliemistry, and Mr. Kings ley. Professor
of Languages, in Yale College .. 232

L. Me77toir Upon the Torpidity of Monkeys and other Ani-
mals. Translated from the Italian of M. Mangajli,
Professor of Natural History at Pa via . . . . 245

JLI. The reformed Sexual System of Liiniams. By Robert
John Thornton, M.D., Lecturer on Botany at Guy's
Hospital 253

LI I. Account of the Mamfactures carried on at Bangalore ^
and the Processes employed by the Natives in Dyeing Silk
and Cotton 259

LIU. On the Means of gaining Power in Mechanics 272

LIV. On the Identity of Silex and Oxygen. By Mr. Hume,

ofJU>ng'Acre. London 275

^ LV. Pro-

CONTENTS.

LV. Proceedwgs of Learned Societies 280

LVI. Intelligence a7id Miscellaneous Articles ... 284

LVII. Reduction of the Observation of the Transit of Mer^
citry over the Sun, observed at the Royal Observatory,
Greenwich^ on the Sth of November, 1*802. Commu^
nicated byT. FiRuiNGEK, Esq 289

LVI IF. Geological Journey to Mount Ramazzo in the Ap-
penines of Liguria ; Description of this Mountain ; Dis-^
covery of' the true Variolite in its Bed ; of Lime ; of the
Arragonile ; and of Martial, Magnetic, Cupreous, and
Arsenical Pyrites, in the ^Steatitic Rock ,• Mamfacture of
the Sulphate of Magnesia. By M. Faujas St. Fond 296

LIX. Essay upon Machines in General. By M. Carnot,
Member of the French National Institute, &^c. &c. 310

I.X. On Chemical Nomenclature. By a Correspondent 320

LXI. Account of the Manufactures carried on at Bangalore ,
and the Processes employed by the Natives in Dyeing Silk
and Cotton . . . . . . 322

LXI I. Description of the Bermuda Islands , and particularly
the Island of St. George. Addressed to the Directors of
the French Museum of Natural History, by M. A. F. Mi-
ch Aux, temporary Agent of the French Imperial Ad-
ministration of Woods and Forests in North America 331

LXin. Facts upon which to found a History of Cobalt and
Nickel. ByM.PROVST. Extracted by M.Chevreuil 337

LXIV. The mean Motions of the Sun and Moon, of the
Su7l's Perigee, the Moon's Perigee and Node ; the Times
of their several Revolutions, both in respect to the Equinox
and to the fixed Stars, and in respect to each other : de-
duced from the New Tables of the Sun and Moon lately
published by the French Board of Longitude. By James
Epps, Esq 347

LXV. Mineralogical Account of the Island of Corsica ; con-
tained in a Letter from M. Rampasse^ formerly an
Officer in tke Corsican Light Infantry, to M. Faujas de
St. Fond .. 351

LXVI. On the Identity of Silex and Oxygen. By Mr.
Hume, of Long-Acre, London 356

LXVIL Report of' Surgical Cases in the City and Finsbury
Dispensaries , for November 1807; containing a Dissection
of a Case of Hydrocephalus in t emus. By John Taun-
ton, Esq 363

LXV III. Notices respecting New Books 365

LXIX. Proceedings of Learned Societies 366

LXX. Intelligence and Miscellaneous Articles ... -370

THE

THE

PHILOSOPHICAL MAGAZINE.

I. On the two Systems of Musical Temperament recorn-
jnended hy Earl Stanhope, — Mr, Hatvkes's System, &c.
By Mr, John Farey.

To Mr, Tilloch.

TT '''''

XIaving bestowed some pains to illustrate the System of

Musical Temperament described by Earl Stanhope in your
xxvth volume, as applicable to keyed Instruments, by the
help of a Monochord, whose divisions are according to
geometric mea?i proportionals, I beg now to present to your
readers, the notes of the other System, described by his
Lordship in the same Essay, to be effected by making three
successive tempered Fifths, and two successive major Thirds^
in <iifferent parts of the scale, beat equally quick respec-
tively.

The table accompanying}; this, is divided into 10 columns,
entitled at the bottom, as has usually been done.

Column 4 contains the number of complete vibrations
made by a musical string or other sounding body in one
second of time, when the intervals are agreeable to Earl
Stanhope's Monochord System 'j whose logarithms, lengths
of strings, and other particulars for comparison herewith,
will be found vol. xxvii. p. 195*, and vol. xxviii. p. 141. /

* I beg here to correct an unfortunate error In the length of string which
I have in this page assigned to Lord Stanhope's 6th, owing to my having
taken out the number answering to the logarithm •8100S00 (instead of
•8010300) viz. '6456987 instead of '6324554; for which correction I wish tq
acknowledge rny obligation to Mr. J. Barraud, a gentleman engaged in these
inquiries, who has verified th^ numbers in this column, except insoijie of their
last places, independent of thelogarithms in the preceding column.

Vol. 30. No. 117. Feb, 1808. A 2 Columns

4 On Earl Stanhope^ two Systems of

Columns 5, 6, 7, 8, and 9, arc intended to explain the
Equal- beating System of his Lordship (see vol. xxv.
pp.301, 302; xxvii. p. 2035 and xxviii. p. 150) : the 5lh
contains the complete vibrations (which Earl S. would call
Beats) made in one second of time ; wherein 2-10 is assumed
as the pitch of 'C on the Tenor Clift' line (a ledger line be-
low the Treble, or the same above the Bass stave in music),
on the authorities quoted in the article Concert pitch, in
vol. ix. part 1. of Dr, Rees's New Cyclopaedia, lately pub-
lished.

I am aware that Earl Stanhope, (vol. xxv. p. 303,) refers,
in his Tuning Table, to the Octave below, my C instead of
above it, at least for tuning of some of his notes, but
I have preferred this Octave, and added to my calculation,
vol. xxvii. p. 203 ; extending the same to the equally heat-
ing Thirds in this his Lordship's System.

If the Third E bA in his Lordship's Table be tempered
sharp 1-066 commas, and the Third bAc, also sharp '843
parts of a comma, both of these will beat 10*00 times per
second ; and his three successive Fifths GD, DA and Ae,
if tempered flat -4721, -3163 and -21 16 parts of a comma
respectively, will each be found to beat 3*158 times per
second nearly. The half of the number of Vibrations in
columns 4 or 5, or of Beats in this Octave, will answer to the
first Bass Octave, and twice these numbers to the first
Treble Octave respectively; and the half or double of these
again, will express the next descending or ascending Octave
respectively, and so on, throughout the whole scale.

Columns 6 and 7 contain the logarithms and lengths of
strings in this System, for comparison with the notes in his
Lordship's Monochord System, vol. xxvii. p. 195; as co-
lumn 8 is intended, to compare with vol. xxviii. p. 141 ;
in which column, I have preserved the terms f and m,
the same, and thrown all the differences between this and
the monochord system, into the term 2, as the same are
expressed in column 9 : from whence it appears, that half
the notes differ more than l^- Schismas from each other re-
spectively, in these two Stanhopian Systems.

A Table

Musical Temperaments—Mr. Hawkes's Sijstem, &c, 5

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Mr. Hawkcs's System, in
New Notation* — See vol.
xxMu p. 173.

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CO CN C» C-1 >p C><
1 + + + 1 +

Is

The Eq'ual'Bcaiiiig System of Earl Stanhope, expressed in

►

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612-0000 2 4- 12 f + 53 m
5550000 2 + 11 f + 48 m
50«-0000 2 + 10 f 4- 44 m
453 3248 2 + 9 f 4- 39§ m
405-7725 2 + 8 f + 35 m
358-0000 2 + 7 f 4- 31 m
301-7725 2 + 6f 4- 26 m
254-0000 2 4- 5 f 4- 22 m
197-0000 2 4- 4f + 17 m
151-7725 2 + 3f + 13 m
98-9726 2 -r 2f + 8| m
47-7725 2 -h f + 4 m

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C7-, C\\— O -T C^. '-'i O O CO en •*■ O
X 5-0 O r- O CO — V; "JO uo -. CO Q
O) CI u'^ i^ O CM «C t^ O C-1 IT 1- C5
<^ t^ l^ t^ 'X> <Xi <Xi <Ji Ci Oi Ci c-. c>

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C O i' -< O O '^ O O '^ 00 cfo O

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45000

4-26-67

401 66

379^47

360-00

337-31

320-00

300-00

284-60..

268-88 '

252-98

240-00

Vibrations
in 1" by Ear!

Stanhope's
Moncchora

System.

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^ On Earl Stanhope* s two Systems vf

. Since it appears, (vol. xxviii. p. 304,) that Mr. JVilliam
Hawkes asserts the bupcriority of his System (vol. xxvi.
p. 171,) over that of Earl Stanhope, as being '« the best
principle for tempering our present scale*' with 12 notes in
an octave, I have devoted a column of my present Table to
his System, and whereby a comparison of the ?ame may
be made, with either of Earl Stanhope's Systems ; and
where the differences in schismas and minutes, between any
of the respective notes in eacli, may be obtained by a very
easy subtraction.

From such a comparison it will appear, that Earl Stanhope's
notes some of them differ materially from Mr. Hawkes's
corresponding ones, and that both of them differ much,
comparatively, from the Equal Temperament, a mode of
tuning, which Earl Stanhope says, (vol. xxv. p, 291^) was
approved by one half of the most eminent musicians in En-
gland, whom his Lordship particularly consulted on the
subject : although Mr. H. -and his Lordship so cordially
agree, (vol. xxviii. p. 305,) and (vol. xxv. p. 305,) in con-
demning ll^e same.

In my last, I omitted to njention, respecting the Isotonic
system in col-umn 4, (vol. xxix. p. 347,) that if each note
,therein, all of vyhich contain fractional parts of the very
small interval m, be increased to the next 7vhole number,
as 48TVto49liij 4(3^ to 47 m, ccc, these trifling altera-
tions will reduce it to my Equal Temperament, mentioned
vol. xxviii. p. 65, and the same Ccin then be practically
tuned, by the help of perfect conchords only ! ,We may
therefore now hope, that " iLqual. Temperament," which
so many have commended, and others condemned, pro-
bably without having ever heard any music performed in it,
will be brought to the test of experience, and practice suf-
ficiently extensive, to get over the, prejudice which will na-
turally arise, on the hearing of any new system whatever.

Many, I know, have imagined, that the system which
was aimed at by the professional Tuners before Earl Stan-
hope wrote, was an Equal Temperament, to be effected by
the judgment of the ear, and Mr. Hawkes thinks that their
practical results agree very nearly with his system : both of
these opinions I have much reason to doubt, and cannot

refrain

Musical Temperament, -^Mr. Hawkes's System ^ <^c. 7

refrain from again endeavouring to call the attention of some
gentleman, possessed of good Instruments and the necessary
knowledge and experience in making experiments and cal-
culations in harmonics, and requesting him tj> employ the
best .professional Tuners to tune his instruments, without
any intimation to the Tuners, of his intentions or object ;
and before such instruments are put out of tune by use or
standing, to ascertain exactly, by the heats of the dilferent
conchords, by a monochord ; and by other methods also
for further satisfaction, the exact value of every interval in
an Octave, using single strings only : these experiments
varied and repeated, on Organs and Piano-Fortes, tuned by
as many good tuners as possible, would, by their results,
enable us to say, how far any one system whatever has been
adopted, or can be accomplished, by the method of tuning
in use, and within what limits the different tuners, or the
same persons at different times, do in practice fix each note.
Such an one would doubtless perform the most valuable
piece of service to the practical musician, and perhaps enable
him to profit from the labours of theorists in harmonics,
by enabling him with more certainty and facility, to ac-
complifch the '^tuning,*' with which by practice his auditors
are become acquainted, and wherewith most of them are
satisfied*, if the same did not lead to an amelioration of the
system* With such information before them, the musical
public would perhaps 'be enabled to judge, of the preten-
sions of the many musical quacks, who are almost every
year bringing forth some new and fanciful system of tem-
perament, (of which an almost inexhaustible fund yet lay
behind,) and crying up the same with a confidence, equalled
only by that with which rival empirics condemn them:
until at length the Science of Harmonics^ and the valuable
discoveries of Dr, Robert Smith oh the nature of imperfect

* Let It always be recollected, that performances on perfect InsfnLmcnls of by
Voices, are free from defects %n harmony if skill and goed ears but direct them,
and that the present inquiry is limited to the use of Instruments with 12
strings or pipes in an octave, where, or evcu with double that nmmber of
fixed sounds, tcijiperameQts, or errors in harmony ere impossible to be Qvoitled.

A 4 consonances *

S On Machines in General,

consonances, and of Mr, Maxtvell on the system of perfect
consonancijy arc in danger of falling into utter contempt.

1 beg here to mention, respecting the new notation for
musical intei»als, which I have explained vol. xxviii. p. 140,
that the Octave, happening to contkin just 12 of the lesser
fractions f, and one of these to fall near each note of the
equal temperament ; in almost all calculations respecting
DoJizeaves, the temperaments or results, are free of f, and
two only of the three independent or prime terms, of which
every accurate notation must consist, are in general found
at last ; while the smallness of the most minute, m, it being
less than the ttj^^ P^i^t of the Schisma, 2, which is itself
but a very trifle more than -y^th part of a Comma, c,
(6r 7?T 2 + -rV I") render it allowable in most practical
cases to neglect m, and to consider the S s as elevenths of a
comma, in the results ; although I would advise the pre-
vious calculations to be always carried on strictly, in 2,
f and m, especially, as the number of f s will generally point
out, to what finger-key or number of half notes, any step
in the process answers.

I am, sir, your obedient servant,

John Fa ret.

12, Upper Crown-Street, Westminster,
l?€bruary I, 1808.

II. Essay upon Machines in General. By M, Carnot,

Member (f the French Institute, &c, &c.*

Preface, ■

AuTHOUGH tlie theory to be discussed be applicable to
every subject which concerns the communication of motion,
I have given to this work the title of Essay upon Machines
in General ; — in the first place, because it is principally
machines I purpose to treat of, as being the most important

♦ For a 'f ranslat Jon of Carnot's " Reflections on the Theory of the Infini-
fpsimal Calculus," see Phil. Mag. vol. vjii. p. 222, and 335 j and vol. ix. p. 89.

' branch

On Machines in General, §

branch of mechanics ; and in the second place, because I do
not mean to treat of any machine in particular, but solely
of the properties which are common to all.

This theory is founded upon three principal definitions :
the first regards certain movements which I call geometrical,
because they may be determined by the principle of geome-
try alone, and are absolutely independent of the rules of
dynamics. I have not thought that we could easily pass
over them without leaving some obscurity in the elucidation,
of the principal propositions, as I have particularly shown
with respect to the principle of Descartes.

By the second of my definitions, I endeavour to fix the
signification of the ie,vm6 force soliciting and force resisting :
we cannot, in my opinion, perspicuously compare causes
with effects in machinery without a marked distinction be-
tween these difierent forces ; and this is the distinction
upon which I think something vague and indeterminate has
been always left.

Lastly, my third definition is that by which I give the
iiame of moment of activity of a power, to a quantity in
which a power is mentioned which is really in activity or in
movement, and where we also take account of each of the
instants employed by this force, i. e. of the time during
which it acts. Whatever it be, we cannot refuse to allow-
that this quantity, under whatever denomination we de-
signate it, is not to be continually met with in the analysis
of machines in movement.

With the assistance of these definitions, T arrive at pro-
positions which are very simple : I deduce all of them from
one same fundamental equation, which, containing a cer-
tain indeterminate quantity, to which we niay attribute dif-
ferent arbitrary values, will give successively m each par-
ticular case, all the determinate equations required for the-
solution of the problem.

This equation, which possesses the greatest simplicity,
generally extends to all imaginable cases of equilibrium and
movement, whether the movement changes hab^tiiv, or va-
j;\es by insensible degrees : it is even applied to atl bodies,
whether hard, «r endowed with a cerbin degrc^ti of elaslicilv ;

at>d

10 On Mathines in Generate

and if T am not deceived, it is sufficient of itself, an4 inde-
pendently of every other mechanical principle, to resolve all
the pHFticular cases to be met with.

I easily draw from this equation a general principle of
equilibrium and movement in machines properly so called,
and from the latter naturally flow o>her principles more or
less general, several of which are already known and very
celebrated, but which have been hitherto eirtier inexactly or
vaguely explained, rather than rigorously demonstrated.

Without departing from general principles, I have united
in a scholium, and as clearly as possible, the most useful
remarks for practice, and which, ^om their importance^
appeared to me to merit a par:icular development. Every
person repeats, that in machines in movement, we always
lose in time or in velocity what we gain in power; but after
perusing the best elements of mechanics, which seem to be
the true place where the proofs and explanation of this prin-
ciple should be found, — Is its extent or even its true, signi-
fication easy to seize ? Has its generality, with most readers^
that irresistible evidence which should characterize mathe*
rnatical truths ? If they exhibit this striking Conviction,
ought we not to see mechanics instructed in th<jse works,
incessantly, renounce their chimerical projects ? Would they
not cease to believe, in spite of every thing that has been
taught them, that there is something of magic in niachines ?
The proofs given .them of the contrary only extend to
simple machines : now they do not think these capable of
any great effect, and they cannot be brought to believe that
it must be the same in every case imaginable; they only
speak of that where there are solely two forces in the system^
and they are contented with an analogy : this is the reason
why these mechanicians always hope that their sagacity will
make them discover some unknown resource, some ma-
chine which is not comprehended within the ordinary rules;
they think themselves so much the more certain of meeting
with it, the further they remove from every thing which
seems to have any relation with machines in use, because
ihey itnagine that the theory established with respect to the
latter, cannot be extended to constructions which do not

seem

On Machines in Generali \i

seem to have any connection with them. It is in vain to tell
them that every machine may be reduced to the lever ; thiii
assertion is too vague and too wire-drawn to be admitted .
without a profound examination ; they cannot persuade
theinstlvcs that machines which appear to have notliing in
common with those denominated simple ones, arc subject
to the same law, nor that we can pronounce upon the in-
utility of a secret winch has not been connriunicatcd to any
person : thence it happens that, the most absurb ideas, and
the furthest removed from the simplicity so advantageous to
machines, arc those which furnish them the most hopes.

The method of rooting out this error is, certainly to attack
it in its very source, by showing that not only in all the
machines known, but also in all possible machines, it is an.
invariable law — that we always lose in time or in velocity
what we gain in power, — and to explain cleady what this
law signifies ; but to thi§ effect we must raise ourselves to
the greatest generality possible, and not stop at any parti-
cular machine, or resort to any analogy^. In the last place,
there must be a general demonstration, 'deduced imme-,
dialely and geometrically from the first axioms in ifiecha-
nics : this is what I have atten^pted in this Essay. I have
strongly insisted upon this fundamental point, and I do not
know' if f have succeeded in placing it in a sufficiently clear,
light ; but on attacking error we are compelled to substitute
truth in its place; — 1 have shown what is the true end of
machinery: if it be unreasonable to expect prodigies from-
them beyond all probability, we shall still find there is
plenty of utility in them for exercising the most lively ima-
gination.

The reflexions T propose upon this law lead me to say a.
word of perpetual motion : and I have shown not only that,
every machine abandoned to itself must infallibly stop, but
I assign the- verv instant when this must happen.

There will also be found among these reflections one of
the most interesting properties of machines, which I think
has not yet been remarked ; it is, that in order to make them
produce the greatest possible eflTect, it must necessarily
happen that there be no percussion, i.e. that the move-
ment

1 2 Qn Machines in General.

inent should always change by imperceptible degrees; which
occasions, among other things, some remarks upon hy-
draulic machines.

Finally, L terminate this production by some reflection!*
upon the fundamental laws of the communication of move-
ment, which, if they be not agreeable to every body, have at
least the merit of brevity.

I repeat that this Essay has merely for its object machi-
nery in general ; each machine has its peculiar properties :
here we have only to do with those which are common to
all ; these properties, although sufficiently numerous, are in
some measure all comprehended in one very simple law :
it is this law I purpose to explain, to demonstrate, and de-
velop, always regarding machines under the most general
and direct point of view.

Introduction.

I. There is no want of excellent treatises upon machi-
nery: the properties peculiar to those in frequent use, and
particularly to those called simple, have been inquired after
and expounded with all possible sagacity. In my opinion,
however, too little attention has been bestowed in the de-
velopment of those iproperties which are common to ma-
chinery in general, and which for this reason no more
belong to the cords of a machine than to the lever, the
vice, or any other machine, whether simple or com-
pound.

It is not, however, because geometricians have neglected
to ascend to the general principles of equilibrium or move-
ment ; but it is only, as it were, en passant that they have
spoken of their application to the' theory of machines pro-
perly so called : and perhaps there is none of these prin-
ciples to be found whteh unites to a rigorous demonstration
a sufficient generality, to make it answer solely and in-
dependently for the solution of the various questions which
may be proposed, as well upon the equilibrium as upon the
movement of machines, i. e. for reducing every question to
a business of geometry and calculation ; — this is the true
object of mechanics.

II. Among

On.Machines in General. ' 13

TI. Among the principles more or less general which
have been hitherto proposed, we shall only mention two
very celebrated ones, and upon which we shall have some
observations to offer.

Tiic first is that which assigns for -the general law of
equilibrium in weighing machines, that the centre of gravity
of the system is then at the lowest possible point ; but al-
though this antient principle be very simple and gt-neral, it
does not seem that all the attention it deserves has been paid
to it : it is certainly, first, because it is subject to some ex*-
pressions, like all these where a maximum and iQ,inimum is
mentioned : second, because it has no relation except to a
particular species of force, which is gravity : thirdly and
lastly, because it appears difficult to give a general and rigo-
rous demonstration of it. But first, we shall show that by
a small change in the display of this principle, we may make
of it a very precise, geometrical, and true proposition,
without any exception whatever. Secondly, although it
has no relation except to giavity, yet it is easy to apply it
to all imaginable cases : for this purpose it is only re-
quisite to substitute a weight in the place of each of the
powers which are of a different genus ; this is very easy by
means of a line passing upon a return pulley, in such a
manner that there now remains no other defect to this prin-
ciple than that of being indirect. Thirdly and lastly, al-
though we cannot demonstrate it rigorously without ascend-
ing to the first principles of mechanism, it is, however,
easy to account for it so as to remove every doubt, if we
had even no other proofs, as we shall show when we come
to the exact demonstration which we shall endeavour to give
of it in ihe course of this Essay.

Let us imagine therefore a machine to which there are no
other forces except weights applied ; I suppose it, besides, to
be of any arbitrary form, but that no movement has been
given to it; this being done, whatever be the disposition of
the bodies of the system, it is clear that if there be equili-
brium, the sum of the resistances of the fixed points or any.
obstacles, estimated in the vertical direction, contrary to the
gravity, will be equal to the total weight of the system ;
2 hi\%

1 i On Machines in General.

but if a movement is given^ a part oF the gravity will be
employed to produce it, and it is only with the surplus that
the fixed points will be charged ; thus, in this case the sum
of the vertical resistances of the fixed points will be less at
the first instant than the total weight of the system : thus
from these two forces combined (the gravity of the system
and the vertical charge of the fixed points) there will result
from it a single force equal to their difference, and which
will push the system from top to bottom as if it were free:
thus the centre of gravity will descend necessarily with a
velocity equal to this difference divided by the total mass of
the system. Again, if the centre of gravity of the system
docs noi descend, there will necessarily be an equilibrium.
In general therefore — For ascei'taining that several Lueights
applied to any given mackine should make a mutual equili^
Iriinn, it is sufficient to prove that if' we abandon this ma-
chine to itself) the centre , of gravity of the system luitlnoi
descend.

III. The immediate consequence of this principle, which
is true without exception, is, that if the centre of gravity
of the system is at the lowest possible point, there will ne-
cessarily be an equilibrium ; for, according to this proposi-
tion, it is sufficient, in order to prove it, to shov/ that the
centre of gravity will not descend : Now, how could it de-
scend, when upon this hypothesis it is at the lowest point
possible ?

IV. In order to give another application of this principle,
I suppose tbat it Ts required to find the general law of equili-
brium between two weights, A and B, applied to a given
machine : I say then, that in consequence of the preceding
principle, there will be an equilibrium between these two
weio:;hts A and B, if by supposing that one of the two has.
to bear it, and the machine has to take a small movement,
it would happen that one of these bodies would ascend while
the other descended ; and that at the same time these
weights were in the reciprocal rates of their estimated velo-
cities in the vertical direction : in fact, if we suppose that
A then descends with the vertical velocity V, while the ve-.
loclty of B, also estimated in the vertical direction would be

8 u, we

Memoir upon living and fossil Elephants, 15

?/, we shall have' by hypothesis, A : B : : 2^ : V, or AV=

B 2/, therefore -^-TTq' = ^' ^^^^^ ^^^"S ^^"^> *^?^^ ^^^
bodies are supposed to be in motion, the one from top to
bottom, and the other vice versa, jt is evident ihat the first
member of this equation is the vertical velocity of the centre
of gravity ot" the system : thus this centre of gravity will
not descend, and therefore by the preceding position there
must be an equilibrium.

[To be continued.]

III. Additional Memoir upon living and fossil Elephants,
By M. CuviER.

[Concluded from vol. xxix. p. 254.]

Article VII.
Comparison of the Crania of the Elephant of India and that
of Africa — External Characters taken from the Ears —
Parts of tile Cranium susceptible of Variation in one and
the same Species.

JL HAD the good fortune to be the first to remark, in 1795,
the distinctive characters presented by the crania of the two
elephants, and which are so much the more interesting, as
they may be applied to living, or entire individuals, without
being obliged to examine their jaws*. I was able to re-
cognise them at first only by the comparison of' a cranium
of each species ; I have -now verified these observations by
inspecting seven real crania, (five of which are Indian, and
two African,) and several drawings.

When these crania are separated from their lower jaws
and placed upon the grinders, and upon the edges of the
alveoli of the tusk;5, the zygomatical arcades are nearly ho-
rizontal in both species.

If we next view them laterally^ what is very striking is,

• Plate II. was long ago engraved from my own drawings. I gave a proof
Impression of it several years ago to M. Wiedeman of Brunswick, who copied
it into his Archives de Zootomie, tome ii. cah. I. pi. I. — The Author*

that

1 G Memoir up6n livmg and fossil Elephants,

that the summit of the head is almost round in the African
elephant, and that it rises in the Indian elephant into a kind
of double pyramid.

This summit answers to the occipital arcade of man and
other animals, and is so high in the elephant merely for the
purpose of giving to the occipital face of the cranium a suf-
ficient extent for a cervical ligament and occipital muscles,
proportionate to the weight of the enormous mass they have
to support.

This difference in the form of the summits proceeds from
the difference in the inclination of the frontal line, which
retreats much further in the African elephant, where it
forms with the occipital line an angle of 115°, than in the
Indian elephant, where it makes an angle of 90° only.

From this come the principal differences of the profile,
such as, 1st, The proportion of the vertical height of the
head at the distance from the end of the bones of the nose
to the occipital condyles, which are nearly equal in the
African elephant, (being as 33 to 32,) and the first of which
is nearly one-fourth larger in the Indian elephant (being
as 24 to 19). 2d, The proportion of the distance from
the edges of the alveoli of the tusks at the summit to a line
which is perpendicular to it and goes from the end of the
bones of the nose to the anterior edge of the occipital hol-
low. The first of these lines is almost double that of the
other in the Indian elephant (being as 26 to 14). It is little
less than one -fourth larger in the African elephant (being
as 21 to 16).

Besides these in the proportions, there are also differences
in the contour: Ist, The front of the Indian elephant is
followed into a sinking and concave curve ; that of the
African elephant is on the contrary a little convex. 2d,
The sub-orbitary hole is larger in the Indian dephant. In
the African, It resembles a channel rather than a simple hole.
3dly, The temporal hollow is rounder in the African ele-
phant ; and the apophysis, which distinguishes it from the
orbit, is thicker than in that of India, in which this hollow
has g,p oval contour.

When

Memoir upon livi?ig and fossil Elephants, if

When observed by their front view^ these crania also pre-
sent very remarkable diflferences.

1st, The greatest length of this front, taken from the
summit to the edge of the alveolus, is at its greatest breadth,
taken between the post-orbitary apophyses of the fronial
bone, as 5 to 3 in the Indian elephant, and as 3 to 2 in th^
African elephant.

2d, The aperture of the nose is nearly in the middle of
the iacc in the Indian elephant; it is one-fitth further re-
moved from the edge of the alveolus than from the summit
of the head in the African elephant.

When seen from above, these crania differ, particularly by
their zygomatical arcades j they Ifre more salient in the
African than in the Indian elephant.

When we look at them behind, we are struck with new-
characters :

l3t, The height of the v/mgs of the sphenoidal bones,
forms in the Indian elephant more than three-fourths of
that of the occipital surface, while in the African elephant
it scarcely forms one half,

2d, In the African elephant the posterior extremity ot
the zygomatical arcades is nearly on a level with the occi-
pital condyles ; in the Indian elephant it is mtich lower.

3d, The occiput is terminated in the upper part in the
African elephant, by a semi-elliptic curve, and its base is
formed by two lines in a very open angle. In the Indian
elephant, the sides are in convex arcs, and the upper part of
the arc is slightly concave.

■ The grinders are placed in both species upon two lines
which converge before; they differ only by their laminae, as
we have said above.

Most of the characters we have described, contributing
to the -general configuration of the head, are sensible
externally ; there is one still more prominent^ and which
may, distinguish the two species at the first glance. 1 think
T was the first to remark it : it consiiJts in the size of the
ears.

The Indian elephant has middling-sized ears : — they are so
large as to cover the whole shoulders in the African elephant,
, Vol. 30. No. 117. Feb. 1808. B I made

1 8 Memoir upon living and fossil Elephants,

I made myself certain of the first point : 1st, In three
elephants which I saw alive ; and I dissected two of them :
two were fi*oni Ceylon, and the third from Bengal. 2d,
In two other individuals which I saw in a state of preserva-
tion. 3d, In all the figures well known to belong to the
Indian species, particularly those of Buffon, Blair, and
Camper. 4th, In the figure of a foetus elephant from Cey-
lon, described by Zimmermann, in a quarto volume upon
the subject *.

^ Upon the second point, I have the following proofs :
1st, The elephant from Congo, dissected by Duverney. We
may see its figure in the Memolre pour scrvir d VHist. des
Anim. par. iii. j and I tm sure that the ear is not exagge-
rated, for it is still preserved in the Museum, and I have
seen and examined it.

2d, An ear preserved in the king of Denmark's cabinet,
and taken from an elephant killed at the Cape of Good
Hope by captain Magnus Jacobi, in 1675. It is three
feet and S half long, and two feet and a half broad f.

3d, A young African elephant in our Museum ; its
ears, although shrivelled up by being dried, are still as large
as its head.

4th, An embryo elephant from Africa, in our Museum.

5th, All the well-known figures of the African elephants.

From these characters we may be assured from what
species those figures have been drawn the origin of which
is unknown, or such as are to be seen on antient monu-
ments.

Thus' that of Gessner J, copied by Aldrovandus §, is an
Afirican elephant. That of Valentine ||, copjed by Labat^,
and altered by Kolbc **, is equally so.

On the contrary, those of Jonston ff, which are very
good, and which have served as a model to those of Har-
tenfelsjt, from which Ludolph §§ afterwards borrowed

• Erlang, 1783, in 4to. f Oliger Jacobaeus, Mus. reg. Dan. 1697, fol. p. 5.
f Quad. p. S77. § Quad. lib. i. p. 465. \\ AmphitheAtr. Zoot. tab. i. f. 3.
5 Afr. Occ. iii. p. 27 1. ** Relation du Cap. trad. Fr. in 12mo, tome iii. p. II.
ff 'Qttadr. tab. vli. viii^ ?tix. \\ Elephantograph. curious, passim.

§§ .^thiop. lib. i. c^^p. 9.

his;

Memoir Jipon living and fossil Elephants. I9

his ; that of Neuhof *, the tusks of which are too high ;
that of Edwards f, the head of which is too round, because
it is taken from a young subject, to which it was necesssary
•to add tusks, are all Indian elephants.

The two figures in BufTon J, copied by Schreber §, and by
Alessandri||, are the two sexes of the Indian species,

Mayer gives a tolerable figure of a male dauntelah^
(vorstell. allerh. thiere, i. pi. Ixix. ;) but the skeleton
(ib. Ixx.) is copied from Blair, without any correction.

The elephant foetus preserved in the East India Com-
pany's house at Amsterdam, and represented by Seba,
(tome i. pi. cxi.) is also of the Indian species.

The limits between the Indian and African species was
already distinctly enough traced with respect to the various
parts of the head, and without having occasion to resort to
the other characters, which we shall point out by and bye,
and which are supplied by the number of the nails, and
the forms of various bones of the limbs ; but before being
able to apply with certainty the osteological characters of
the cranium to the fossil elephant, we must determine what
are the variable parts of one individual from the other, in
one and the same species. 1 have therefore subjected my
Indian crania to a comparison with each other, and I did
the same with my African ones.

The latter presented me with scarce any appreciable dif-
ference.

As to the former, T found svme with respect to the
occiput and the alveoli of the tusks.

The occiput is more swelled in every direction in the
former than in the latter, without regard to» the length of
the tusks.

The alveoli of the tusks of th^ dauntelah are a little more
oblique in front ^ those of the mookna are a little straighter
towards the bottom.

The latter are a little smaller, but by no means so much
so in the proportion ^ of . the tusks themselves. What is

* Ambass. Orient. Descr. Gen. de la Chine, p. 94. f Av. 221, f. 1.

\ Hiit. Nat. xi, PI. L ct Suppl, § Quad. ii. Jab. 78. {| Quad. i. PI. ii.

B 2 deficient

ft<^ Membir upon living and fossil Elepkantsx

^cRfcrcnt in the size of the tusks is compensated by a greater
thickness in the osseous substance of the alveolus. The
Teason is, that the alveolus, serving as a base and a socket
f6r the muscles of the proboscis, could not shrink as well
as the tusks, without the proboscis losing the strength and
thickness which is necessary for it.

Lastly, There is a little variety in the length of the alveoli;
and, what is very remarkable, even without any reference
with that of the tusks. Our large mookna skeleton has
riiem longer than our two dauntelahs, although its tuska
are the smallest of all. To conclude, — this increase in length
does not exceed an inch.

It could not be considerable without the organisation of
the proboscis being essentially changed, because the mus-
cles of its lower part are inserted under the lower edge of
the alveoli of the tusks, and those in the upper part are in
the front, above the bones of the nose. The base of the
proboscis has therefore necessarily for its Vertical diameter
the distance between these two points ; and if the alveoli
are prolonged beyond a certain measure, the proboscis would
assume a monstrous size.

It is very important to notice this article, because it fur-
nishes the most distinctive character of the fossil elephant.

If we compare together the small number of figures of
elephants* skulls found in the works of naturalists, I do not
think any stronger differences will be found than those I
have riientioned.

The table annexed to the succeeding article expresses
^ese differences by numbers.

A celebrated author has supposed a difference between
the crania of males and females, which we have not men-
tioned, but he has been deceived by simple external ap-
pearances.

Our small mookna from Ceylon had, at the root of the
proboscis, a very perceptible protuberance, which the female
bad not. M.^ Faujas, imagining that this protuberance be*
longed to the osseous parts, has represented these two
heads in PI. xii. of his Essais de Geologic, *' In order to
avoid/' he says, p. 238, <* falling into an error, when we

find

Memoir upon living and fossil Elephants, 21

find the heads of a male and female fossil elephant, we must
not mistake them for two different species."

Dissection has shown us, however, that this protuberance
was only produced by two cartilages peculiar to elephants,
which cover the entrance of the canals of the proboscis into
the osseous nostrils.

These cartilages were a little more swelled in this indi-
vidual than in the others.

It is not even a character common to all males. The
dauntelah of Bengal had it not.

The same learned geologist has given to his figures much
larger tusks than these two individuals had in reality, ^^ In
order," he says, p. 26j^, ^^ to make those understand, who
never saw an elephant, the manner in which these animal*
carry their tusks." It was not necessary, however, to give
large tusks to the female, which never has any in the Indian
species.

Article VIII.

Examinatioji of the Cranium of the fossil Elephant,

The cranium was very cellular 3 the osseous laminas com-
posing it were too thin to be preserved in the fossil state :
they are therefore found in innumerable fragments ; but
three only are mentioned as being in a state of good preser-
vation, and the most entire of the whole wants a part of
the occiput.

They belong to the Petersburgh Academy * ; the best
was found upon the banks of the river Indigirska, in the
most eastern and coldest part of Siberia, by the learned and
intrepid Messerschniidt of Dantzick, who gave a drawing
of it to his countryman Breynius. The latter had it en-
graved at the end of a memoir he inserted in the Philo-
sophical Transactions fj and to this day it is the only public
document ne have upon this part of the skeleton of the
fossil elephant.

I have copied the figure of Breynius in PI. ii. fig. \, be-
sides the African and Indian crania; and I have reduced
the three to the same size nearly, in order to facilitate their

* Pallae, Noy.Com. Petrop. xui. | Vol. xl. n. 446, pi. i. and Ji.

B 3 comparison.

29 Memoir upon living and fossil Elephants,

comparison. The first glance shows that the fossil ele-
phant resembles, in its cranium as well as in its teeth, the
Indian species rather than any other.

Unfortunately the drawing is not correct enough for an
exact comparison, and it is not made upon a weil-deter-
mined projection. The part of the alveoli, that of the con-
dylon for the lower jaw, and the anterior edge of the
temporal hollow, and of the orbit, are seen a little obliquely
behind, while the occiput and the grinders are in a rigorous
profile.

We see distinctly enough, however, a striking difference
in proportion in the extreme length of the alveoli of the
tusks. It is treble what it would be in an Indian or African
cranium of the same dimensions ; and the triturating sur-
face of the grinders prolonged, in place of meeting the
alveolary edge, would intersect the tube of the alveolus at
one-third of its length.

This difference is so much the more important as it agrees
with the form of the lower jaw, as we see below ; and, as
we have already said, it would of necessity produce an-
other conformation in the proboscis of the fossil elephant ;
for where the sockets of the muscles of the proboscis were
the same, i. e, the upper part of tjpe nose and the lower
edge of the alveoli of the tusks ; in this case the base of
that organ was three times larger in proportion than in our
living elephants ; or rather the sockets of the muscles were
different, and a fortiori its total structure was different.

If we could trust entirely to drawings, we should also
fjnd> 1st, That the zygomatic arcade is differently figured;
2d, That the post-orbitary apophysis of the frontal bone is
longer, more pointed, and more crooked; ,3d. That the
tubercle of the lacrymal bone is much larger and more salient.

As to the absolute size of the fossil cranium, compared
with our living crania, we may form an idea of it from
Plate iv. fig. 9, MO, 11, where I have represented the three
crania in front, and upon the same scale,

We may form a still more correct idea of their size from
the following table, in which I have collected the dimen-
iions of all th? crs^nia with which I am acquainted.

TsiblQ

Memoir upon living and fossil Elephants,

2»

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ditto

of the

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$4 Memoir vpcni living and fossil Elephants,

But in order to infer from any one of these crania the
dimension^ of the animal to which it belonged, it is not
necessary to refer to its first dimensions, into which the
excessive length of the alveoli of the tusks enters ; these
oiily should be taken into consideration which are really
homol.)p;ous.

Now, by comparing them with those of the cranium of
our Indian skeletons of the mookna and comerea, we find
that the fossil animal must have been nearly twelve feet
high. A comparison with the skeletons of the Indian
dauntelah and meyfiBe would give a little more to the fossil.

As soon as I was acquainted with this drawing of Messer-
schmidt, and added to the differences it presented those I
had myself observed in the lower jaw and in some isolated
teeth, I no longer supposed that the fossil elephants were of
a different species from those of India.

This idea, which I first announced in a memoir to the
Institute, opened quite new views to me upon the theory of
the earth ; a hasty glance at other fossil bones induced me to
presume every thing I have since discovered, and determined
nie to devote myself to the assiduous researches and tedious
labours in which I have been occupied these ten years past.
I ought therefore to acknowledge, that it is to this draw-
ing, buried as it were in the Philosophical Transactions for
seventy years, that the public are indebted for all those
Works upon which I set so high a value.

I must not dissemble, however, that the characters it
presented me required to be confirmed by some other speci-
men, in order that they might not be considered as the same
species, and in spite of their agreement with those of the
lower jaw, I was happy to find a drawing of another
cranium.

I ap|1ied to the Petersburgh Academy; and this illustrious
body, to which I now belong, complied with my wishes,
with a generosity worthy of a Society to which science is so
much indebted.

The Academy ordered a superb coloured drawing of the
natural size to be transmitted to me of another fossil cranium
from Siberia, in their collection also. It was accompanied

with

Memoir upon living and fossil Elephants. 25

with a drawing of the lower jaw of a cranium of a rhino-
ceros, in two positions. In these drawings I found a con-
firmation of what I had conceived from seeing Messer-
schmidt.

The cranium, which served for the model, is not so com-
plete. The grinders, and a part of their alveoli, are want-
ing, as well as the middle part of the zygomatical arcade.
Nothing characteristic is however missing : there is the
same'length and the same direction of the alveoli ; the same
size of the lacrymal tubercle_, and the same general form :
every thing in fact convinces us that the fossil skulls partake
of the same characters.

I have carefully engraved this fine drawing in my Plate
viii. fig. 2.

The parallelism of the grinders is a difference which may
be established independently of the drawings of Messer-
schmidt or of the Petersburgh Academy. /

M. Jaeger assures me of the same fact, with reference to
a portion of a cranium in the Stutgard cabinet, and which
may be found in my Plate \v, fig. 4 : another piece, drawn
by Peter Camper, shows the same character*. I have copied
his figure, Plate iv. fig. 3, and I have placed beside it
fi^. 1 and 2, those of Indian and African crania, seen from
below, in order to show the more remarkable convergency
of their front teeth.

We have in our Museum a portion of the occiput and of
the temporal bone of a fossil elephant, brought from Sibe-
ria by the astronomer Delisle, which aflforded me an oppor-
tunity of comparing these parts more closely than the others,
of which I had drawings only ,• but I found some very
trifling differences ; I have given a back view of it in fig. 7,
and a lateral one in fig. 8, of Plate iv. This specimen be-
longed to an elephant ten feet high.

* Mem. de Haarlem, torn, xxiii. P1.D.

IV. Ob-

■ [ 36 ]

IV. Observations upon the Employment of M. Guyton-
MoRVEAu's Fuinigations for preventing contagious In*
fection. By M. A, Hedouih, Physician*,

1. HE prison of Mont Sanit Michel, from its situation,
stood more in need that any other of some chemical agent
to correct the numerous locial vices in point of salubrity.

Putrid and malignant fevers, so familiar among individuals
crowded together in the same place, using food of slender
succulency, and overwhelmed with grief and sorrows, raged
with unceasing fury in the prison of Mont Saint Michel.

Juniper berries and incense were frequently burned in the
cells ; but instead of changing the atmosphere and neutrali-
zing the vapours exhaled from the bodies of the sick prisoners,
these means only disguised the sniell. From the moment
M. Morveau's method was resorted to, the number of these
fevers, and of course the mortality, sensibly diminished. .

In ocder to be convinced of these truths, it is sufficient, in
my opinion, to inspect the necrology of this prison, and to
compare the mortality of various years, having an eye to
the increase and diminution of the number of prisoners.

Necrology of the Prison of Mont Saint Michel, from the
Year 1 802 . to the Year 1 807.

Years.

Number of

Number of

Prisoners.

Deaths.

Observations.

1802

from 96

24

The oldest had not attained his

to 100

70th year; all of them died
of putrid fevers, with few
exceptions.

1803

100

11

The oldest not 50.

1804t

from 96

21

The putrid fever carried off 17-:

to 100

two prisoners who survived
it lost all their toes.

1805

120

9

Two only died this year of
putrid fevers.

1806^

No putrid fevers during these

and V

140

6

fifteen months, being the

1807 J

whole of 1806 and three
months of I8O7.

♦ Ann^ de ChimiCy torn. hii. p. 113,

f Jn this year the regular use of fumigations was ordered, and the prison
was furnished with two sets of jVI. Dumontier's apparatus.

It

On Fumigations for preventing contagious Infection . 27 ' f

It was ill the year 1801 that I succeeded M. Komilly,
who fell a victim to a putrid fever, which he caught while
administering relief to the prisoners ; and 1 was astonished
to find more than one half of these unfortunates attacked
with this species of fever. ^._4;^,«s^^*^c.

The cells of the prisoners had a fetid smell, of so pungent
and tenacious a nature that my clothes retained it four-and-
twenty hours after their exposure to the i'rQc air. In these
circumstances I hastened to employ M. Guyton's process*
A mixture of muriate of soda, black oxide of manganese,
and sulphuric acid, was put into proper vessels, which I
ordered to be taken into the cells several times. This process
was repeated the following day by M. Ifidou.

These experiments were attended with no accident what-
ever, and produced a very seasible diminution of the fetid
smell with which the air of the prison was impregnated -,
and we had the satisfaction v^ery soon of seeing the epidemy
of putrid fevers also diminished.

In order to obviate the dangers which this mode of cleans-
ing the atmosphere presents, particularly where there are no
other apartments to remove the patients into, M. Costaz,
prefect of the department, furnished us with the large
apparatus of M.' Dumontier, since which period these
machines are carried through the hospital several tiiijes
daily.

Since the commencement of 1804, the number of pri-
soners has increased one-third ; the structure of the cells

• has not been changed, the same misepy pervades every
corner of them, nor has the amelioration in the food of the
miserable inhabitants arising from their labour, been suf-
ficient to change the nature of the diseases vvitli which tjiey
are infected ; and yet putrid fevers have almost entirely dis-
appeared,

I am certainly of opinion that M, Guyton*s process was

\^ the means of extinguishing the putrid fever in the prison.

1 am the more inclined to believe in its efficacy from ilie

• circumstance of this fever being epidemical in several neinh-
bouring districts, which occasioned an order by the prefect
to fumigate the churches; and from the year 1804 to this

period,

v>

98 On the Effects of Fumigatmjjs

period, there have been only four cases of putrid fever m
the prison ; a striking difference, when we consider the mor-
tality frorn epidemies in the preceding years.

V. Letter from M. Guyton de Morveau upon the
Effects of Fumigations in Epidemies of Cattle^ and for
the Destruction of putrid Miasmata *.

14th of April, 1807.

X HE communication of M. Hedouin has induced me
to think that it would be interestirig to publish an account
of the advantages resulting from the employment of my
anti-contagious process on other occasions. I am extremely
sorry to observe, however, that in spite of the solicitation
of the government, this method is not generally known or
practised j for in the Journal de Paris of the 1 7th instant, we
find that a contagious- disease appeared in the prisons of
Dreux, and that all the judges of the tribunal of criminal
justice had been seized with it and died.

The following two facts I have received from undoubted
authority :

1. About the end of last autumn, the rot made its ap-
pearance in some parishes in the department of Loire and
Cher. Madame de P., the proprietor of two flocks of Merino
sheep, ordered fumigations of oxy-muratic acid to be made
in the folds and stables : at first in open vessels, by pouring
sulphuric acid upon the mixture of sea-salt and oxide of
manganese ; and afterwards, by means of the large apparatus.
The success of this induced her to intimate throughout the
parish, that she would lend the apparatus to those wlio had
diseased sheep. A farmer in the same commune had al-
ready lost several sheep, and he applied the preservative.
He opened the apparatus twice a-day, for three minutes at
each time, according to the instructions he had received.
The rot became mild ; one half of the flock were not affect-
ed with it, and he did not lose a single sheep.

* AnTu de Chimitf torn. liu. p. 119.

Two

in the Epidemies of Cattle, 29

Two other farmers of the same commune made a simi-
larly successful experiment. Their diseased flocks were al-
lowed to pasture along with the heahhy, the latter having
been previously fumigated in the folds, and no contagion
was communicated. The apparatus has of course become .
of general use in the department.

2. The second fact was communicated to me by th6 di-
rectors of the hospitals at Besangion.

Several hundred weights of meat had been left neglected
for some tinle in the cellar of the public hospital : it diffused
so infected a smell that it was impossible to enter the place
to carry it away, and a pitch-fork was used for that pur-
pose. They afterwards introduced into it, with the same
precautions, a flask of anti-contagious gas, the flap of
which was opened and the door of the cellar was closed.
When this flask was withdrawn a few hours afterwards,
there existed no smell whatever, except that which was
diffused by the oxy-muriatic. Its emanations having been
very strong, the window was opened, in order to procure a
current of fresh air. The cellar was then so completely
purified that fresh meat was pat into it and completely pre-
served.

The stench occasioned by the carcase of a dead rat was
also destroyed in a few minutes, by the use of the same
apparatus.

The hospitals of the department have been since provided
with the regular fumigating apparatus ; and glass bottles,
containing a supply of sulphuric acid, nitre, and sea-salt, are
placed in the halls, with which the fumigations are repeated
every evening. The benefits resulting from these precau-
tions have been felt in an astonishing degree. Besangon is
always crowded with prisoners of war and, wounded sol-
diers, among whom no contagion whatever has made its
appearance since the adoption of this salutary process.

VI. Ex^

[ 30 ]

VI. ILxptrlments upon the liquid Sf/lphur of Lampadins*
By Messrs, VAuauELiN and KoBiauET *'.

Process,
X-rfAMPADius, who was the first, to observe this particular
fluid, which he callcd*//(/7/?c? .udphnr, obtained it by the
disi illation of pyritous turfs, and pyrites mixed with a cer-
tain quantity of charcoal or saw-dust. Messrs. Clement and
Dcsormes employed the charcoal and sulphur in order to
form completely the liquid sulphur, which M. Lampadius
considered as a combination of sulphur and hydrogen ; but
these chemists announced the process as bfeing very difficult
in its execution, since they had only succeeded once out of
twenty times. Nevertheless, three successive experiments
have furnished us vi'ith results equally satisfactory, and we
have not remarked that they have any other essential pre-
cautions than that of cooling the flasks adapted to the ap-
paratus, in order to avoid the volatilization of 'this singular
substance. We therefore took, as Messrs. Clement and
Desormes directed, finely pulverized charcoal ; we employed
it in a very dry state, and introduced it into a porcelain
tube, to which was adapted, by one of its apertures, a small
retort containing sulphur; at the opposite extremity we
placed a large tube with a simple curvature, which was in-
serted into a flask three-fourths filled with water; care was
taken to make a hollow in that part of the tube which en-
tered into the water, in order that it might serve as a tube
of safety for the porcelain tube; this first flask, which ought
to have three tubulures, has a straight tube at one of them,
and at the third, a tube communicating with a second flask
surrounded by snow or pounded ice ; to this last \\q adapted
a tube, crooked so as to collect the gases. Things being
thus arranged, the porcelain tube is stropgly heated in a
reverberating furnace ; when it is red-hot the sulphur vo-
latilizes ; after a certain time, there passes into the first
flask a liquid of a citron yellow colour, having the appear-
aince of an oil, collecting into globules upon the surface of

• Ann, ie Chimie torn. kl. p. 14^,

Expeiiments upon the liquid Sulphur of Lampadins, 31

the water, and falling to the bottom of the liquor whe^i
they have acquired a certain volume. If we pass too great
a'quanlity of sulpliuFj a portion joins this oil and gives it
more colour and density ; the other is condensed in the first
glass tube, and is fixed the instant it comes in contact with
the water. If the first flask is so near the furnace as to make
the temperature exceed 20 or 25 degrees of Reaumur,
the liquid sulphur boils, is volatilized, and passes into the
second flask, when the cold water completely condenses it.
We remark, that when we heat the charcoal alone, there
is continually liberated carbonated hydrogen gas mixed
with carbonic acid ; that as soon as the sulphur passes, sul-
phuretted hydrogen gas is disengaged in very great quantities,
and that as soon as the liquid sulphur begins to be formed,
little or no gas is liberated.

Physical properties. — The liquid sulphur obtained in the
first operation is of a citron yellow colour, which seems to
be merely accidental, and owing to a superabundant portion
of sulphur, siuce by a new distillation we obtain it perfectly
colourless, very transparent, and of great fluidity ; there
remains in the vessel where it has been rectified a portion
of sulphur, which unites in a mass or in small regular cry-
stals if the distillation has not been carried too far. The
density of liquid sulphur is considerably more than that of
distilled water ; it has a very strong, fetid, sulphurous, pun-
gent, and garlic-like smell. It has an extremely sharp,
pungent, and very cold taste. The astonisbing facility with
which this fluid decomposes the light announces its great
combustibility.

Chemical properties. — When exposed to the air in anv
vessel, it vaporizes very speedily, and without leaving any
residue, Wh^n it is very pure : if we bring it within a few
inches of an ignited body it takes fire very rapidly, yields a
white flame, which latterly becomes purple; it difl^uses a
suffocating smell of sulphurous acid, and deposits upon the
sides of surrounding bodies a yellow dust in every respect
resembling sulphur.

The water in which the liquid sulphur has been received
assumes a milky appearance in a few hours; and the vessels

are

32 Expo'iments tipon the liquid Sulphur of Laynpadius.

are spotted with some deep black specks. This water has
the same smell with the hquid sulphur, although much
weaker, it possesses the property of precipitating several
metallic solutions, and particularly those of lead in an
orange yellow, that of oxigenated nmrcury in white, that
of tin in brick-coloured yellow ; it does not redden turnsole.

Concentrated sulphuric acid does not seem to have any
very remarkable action upon this substance ; latterly, how-
ever, it dissolves a certain quantity, and acquires a fetid
smell.

The nitric acid seems to make it undergo more alteration ;
the liquid sulphur at first occupies the upper part of the
liquid, but upon agitation it is divided into globules, which
unite with great difficulty. Upon placing this mixture in a
convenient apparatus, so as to make the gas pass through
lime-water at a heat of 13 or 18 degrees, an elastic fluid
is liberated, which dots not disturb the lime-water, and
which inflames with the same colour as oxide of carbon.
But the combustion takes place instantly, and sulphurous
acid is extricated after a very pungent smell : the heatiiiust
be extremely well managed, otherwise the sulphur would
pass into the lime-water.

The nitric acid employed in this operation contains no
trace of sulphuric acid ; when we put it nUo oxy-muriatic
acid gas it acquires a citron yellow colour, and in a few
seconds that of the gas disappears ; and if we place it in
contact with the atmospheric air, it diiiuses a very fetid
and arsenical -like smoke in great abundance. It has the
property of taking fire upon being bror.ghi near an ignited
body this gas when well washed also aifloimes, and after
combustion exhales a smell of i^ulphurcus acid, stronger or
weaker in proportion as it has been more or less washed.

We poured upon the liquid isulphur a mixture of the sul-
phuric and nitric acids, but there was no inflammation, and
the action even seemed to be confined to a simple solution,
at least by diluting it with a certain quantity of water the
whole became perfectly clear. Some experiments seem to
show that the weak acids have more action upon this sub-
jitance then the concentrated ones.

I Pure

Experiments tipon the liquid Sulphur of Lampadm. 33

Pure caustic potash acts very feebly upon liquid sulphur :
after some time, however, it is coloured^ and acquires the
property of precipitating several metallic solutions in colours
peculiar to this combination. .... \

Ammonia seems to dissolve it a little more easily, it
assumes a deep yellow colour, and also precipitates the me-
tallic solutions : caustic bar)'tes dissolves it also in a greai
proportion, and . assumes an orange colour ; it precipilalei
the metallic solutions in the same manner. jfUftv-r-Tt

Alcohol seems to dissolve it in any proportion, the solu-
tion is abundantly precipitated by water, and the sulphur
unites in small globules, which fall to the bottom of the
liquid. <

We sec from these first efforts, that nothing Whatever in-
dicates the presence of carbon in liquid sulphur, and they
authorize us to think that it is only hydrogenated sulphur,
if not to suppose that sulphur itself is a compound body, ■
The action of the oxygenated acids upon this substance ap-
pears very remarkable, and seems to indicate a state of sul-
phur analogous to that of the charcoal and the azot in the
gaseous oxides of carbon and azot.

Nbte by M. Vmtqzielin. — The above experiments were
made at my request, by M. Robiquet. They are still far
from demonstrating the nature of the elements of liquid
sulphur : we should have continued them if M. Berthollet
]un. had not announced to the Institute that he was en-
gaged in a similar investigation. I should not now have
published these facts, if I had not.also informed the Insti-
tute that I was of the same opinion with M. Berthollet,
having been busy in examining the composition of liquid
sulphur, and that I had even given M. Biot a considerable
quantity of it in order that he might expose light to its
action, and determine if possible, by its refra'ngent power,
the portion of hydrogen it contained.

Vol, 30. JJq. 117. F^l, 1808. C Vri. Let'

[ 34 ]

VII. Later from the Right Honourable Earl StAnMopE,
relative to Dr. Callcott's Pamphlet on the Stanhope
Ternperameut,

To Mr, TillocL

-, SIR, Stratford Place, Feb. 3, 1808.

1 HAVE just read the paper *^ On the Stanhope and other
Temperaments of the Musical Scale " which is written by
Mr. John Farey, and published in the last number of
your Philosophical Magazine. The inaccuracy of Mr. Fa-
rcy's statement obliges me to inform you correctly what the
facts were.

Some months ago I received from Dr. Callcott a printed
copy of a pamphlet, entitled, " Plain Statement of Earl
Stanhope's Temperament, by Dr. Callcott" He begged me
to look it over, and to correct it, previous to its publication.
But, at that time, I was extremely busy about my nautical
and other important pursuits, which made it very incon-
venient to me to comply with his request. I received from
the Doctor a letter, dated June 10th> 1807, of which the
following are extracts, viz.

" Curiosity has been so strongly excited by the Stanhope
Temperament, that I thought it my duty even to record mv
own errors on the subject ; and therefore have printed 500
copies of the pamphlet, not to sell, but merely to distribute
hereafter, as evidence how incorrect, imperfect, and in-
complete my notions were, compared with the improve-
ments now making by the superior mathematical and expe-
rimental researches of Earl Stanhope."

*' I have ordered the advertisement of publication to be
inserted in all the papers for the 26th of June, and I pledge
myself to print it exactly conformable to your lordship's
corrections, which real copy will be sufficiently distinguished
from the spurious one, by the sole insertion of the four
pages of music at the end.

*' Immediately on the receipt of your corrected proof, I
shall commence my Letter to the duke of Cumberland, to
whom of course I have not yet applied 5 and I have also

considered

Letter from Barl Stanhope. '' "^ 35,

considered that the duke of Cambridge ought to have a
separate and particular address on the subject ; and therefore
another pamphlet, containing a narrative of my original
disHke and subsequent recantation, will be (I am sure) in-
teresting to his royal highness and all the world."

Finding by that letter that Dr. Callcott had already
ordered *^ the advertisement of piilUcatlon to he inserted in
all the papers for the 26th of Jime," 1 resolved to take the
trouble to correct that printed copy ; and, when I had cor-
rected it, I returned it to Dr. Callcott. I did this merely
out of good nature, and in order to prevent an imperfect
statement of 7ny temperament from being published, wheri.
it was in my power to make it more correct. Dr. Callcgtt
did himself send, by Mr. Fergusson, that corrected copy
of the '' Plain Statement,'' to Mr. McMillan the printer,
with directions from him (Dr. Callcott) to print the same.
He also sent, by the same person^ to the same printer, the
manuscript of his letter to the duke of Cumberland.

These facts are a sufficient refutation of the idle reports
which have reached Mr. Farey upon this subject.

As Mr. Farey has obliged me, nmch against my wish, to
take up my pen again on his account ; I must freely confess
that I can perceive no merit in his calculations.

I have expressed the length of the wire which yields the
sound of the perfect qidnt G, in the correct, precise, and
plain language of two thirds of the length of the wire which
yields the sound of the key-note C. This docs not, how-
ever, satisfy Mr. Farey. He is not contented till he has
told us, that two thirds may be expressed by '6066666 ad
infinitiim. ^

He is not even content with this; for he introduces,
moreover, what he terms a '^ new iwtaiion ;'' and he ex-
presses ^^ the relation ivkich the note G hears to the funda-
mental note C, according to the Stanhope Temperament,'^
as follows, namely,

by 338 2 {ox schismas),

+ 7 f (or lesser fractions) .
+ 31m [ox the most miJiute).

This he no doubt considers as greatly advancing the cause

C 2 of

36 On the Decomposition of the Acetate of Barytes

of science, and as rendering the study of music both more
pleasant and uueliigible !!!

What would any man think of a mathematician who
should express the number 8O91 in the following manner?
8000
+ 600
+ 3 score
+ 2 dozen
4- 7.

The difference between a man of real science, and one
who has the ambition to be thought so, is very great. The
first seeks to render difficult subjects, perspicuous and clear.
The other, on the contrary, envelops even the most simple
ideas in the mysterious garb of hard words and scientific
jargofi. If Mr. Farey he of the first of those two classes, I
should recommend to him to simplify and amend his tables.
I am, sir, your most obedient servant.

Stanhope.

VIII. Upon the Decomposition of the Acetate of Barytes ly
means of Soda. By M, Darcet*.

jLn a late number of the Annales de Chimie f, M. Porperes
says, when speaking of the formation of the acetous acid in
bad digestions, that in 9rder to ascertain the presence of
this acid, '^ he saturated it with pure soda, and afterwards
decomposed the acetate of soda by barytes ;" and he adds,
'^ that having set the soda free, he dissolved it in alcohol,
which, by seizing upon the water of solution, operated
the precipitation of the acetate of barytes which was
formed.'*

^The result of this experiment is necessarily inaccurate, as
the following details will prove.

I suppose that .we have a solution of barytes saturated
.bot: if we pour it into acetate of soda, there is immediately
precipitated an infinity of small brilliant and iridated laminas.

* Ann, de Chimie^ torn. l»i. p. 247. f See Phil. Mag. vol. xxvii. p. 352.

hj means of Soda. 37

If we separate them from the liquor after its complete cool-
ing, if we wash them in the smallest quantity of water
possible, and dry them speedily by squeezing them between
several sheets o^' blotting paper, we shall have nothing but
pure crystals of barytes without mixture of acetate. I as-
certained this in the following manner :

1st, T exposed a part of these crystals to the air : in a few
days, the distilled water with which I washed the carbonate
obtained, gave no more precipitate by the a-ddltion of the sul*
phuric acid, the carbonates, or alkaline sulphates. The whole
mass of crystals had therefore been converted intocarbonatCj
which would not have taken place if they had contained
acetate of barytes.

2d, I dissolved two or three grammes of these same cry-
stals in distilled watery the solution blued turnsole paper
which was reddened by an acid ; there was an excess of al-
kali therefore.

I added some drops of sulphuric acid to this solution,
and there was formed a solution of sulphate of barytes. I
tried the liquor again with the reagent paper, and I still
found an excess of alkali. I added by degrees siil phuric
acid, until there was a slight excess of acid in the liquor :
I filtered it, and found no more barytes, but a little free sul-
phuric acid ; this would not have happened if the crystals
had contained acetate of barytes : for upon this supposition^
at the moment when the excess of acid beo;an to become
sensible to the reagent paper, there must have been only a
very small quantity of acetate of barytes decomposed, and
acetous acid set at liberty. The filtered liquor should there-
fore have contained a slight excess of acetous acid, and
more acetate of barytes not decomposed; which is contrary
to the result of experiments.

3d, Tlje mother water of the crystals employed in the
preceding experiments, should contain nothing except the
little pure barytes which the cooled liquor could hold in
solution, besides the whole of the acetate of soda which had
been employed. What also demonstrates the analysis of
these mother waters, is, to pour alcohol into them as-
M. Porperes points out* The brilliatit lanunce which are
Xiomod^l C3 deposited

38 On the Decomposition of the Acetate of Barytes

deposited are nothing else than crystals of barytes : when
tried as I have pointed out above, they only give very pure
carbonate of barytes, and not an atom of acetate. If we
also try these mother waters with the sulphuric acid, or
with the alkaline carbonates, we immediately ascertain that
they contain but little barytes, and plenty of acetous acid :
this becomes still more perceptible if we evaporate them to
dryness, and redissolve the residue in distilled water : for
this solution no longer contains an atom of barytes, but
merely acetate of soda ; the little barytes in it being carbo-
nated during the evaporation.

Hence it follows, that barytes does not decompose the
acetate of soda, and that, on the contrary, if we try the
inverse experiment it will succeed. In fact, we shall decom-
pose the whole of the acetate of barytes by adding a suffi-
ciency of pure soda for saturating the whole acetous acid.

It is not my object to invalidate the conclusion in M. Por^
peres's memoir: they appear to be just, and conformable
to what is already known. I criticize one of the proofs
onlv they have furnished, and I proiit by this occasion to
mention that M. Aufrye and myself have already published,
in the Annales de Cliimie, a memoir upon the Affinities of
Barytes ; wherein we have proved that in the classification
of the alkalis, barytes Should not be placed before potash and
soda, except with respect to the sulphuric and carbonic
acids ; that in every other circumstance, potash and soda
have affinities superior to that of barytes. How docs it hap-
pen, then, that notwithstanding the facts so clearly demon-
strated in our memoir, various authors have continued barytes
in its old order of affinities ? In my opinion, the results
published of experiments ought to be adopted, or refuted by
repeating them and showing their errors.

i shall conclufle this note by calling to my assistance one
of the processes, the excellence of which has been demon-
strated in our operations upon barytes on a large scale ^-r-it is
naturally inferred from the facts above laid down.
, The decomposition of the muriate, the nitrate, and the
acetate of. barytetf, by potash and soda, is so complete and
easy, thai it is qcrtSiinly the sipiples^ \vay pjf procuring in a

laboratory

hj means of Soda, ^9

laboratory the barytes we require. For this purpose we
strongly calcine^ in close vessels, 100 parts of sulphate of
barytes well mixed with 20 parts of charcoal in powder.
After an hour's calcination the crucible is allowed to cool ;
the residue is separated from it ; it is then diluted in water,
and a sufficient quantity of rutrie acid, muriatic acid, or
acetous acid, is added to it : the mixture is then slightly
heated, which liberates a great quantity of sulphuretted hy-
drogen and carbonic acid, of which we must be upon our
guard. When the effervescence ceases, and the reagent
paper announces in the liquor a slight excess of acid, we filter
and evaporate it, in order to decompose the sulphuretted hy-
drogen, and to precipitate the sulphur which was held in
solution*. The residue is re-dissolved in the least possible
quantity of water, and we add to this solution a saturated so-
lution of caustic potash. There is precipitated, even at the
moment of mixture, a great quantity of crystals of barytes ;
the whole is then allowed to settle at the lowest possible tem-
perature for an hour or two : the mother water is then de-
canted, the crystals are washed with a little distilled water, and
dried by pressing them between several sheets of blotting pa-
per, and they are dissolved in the necessary quantity of boiling
v^^ater : the filtered liquor deposits the barytes upon cooling,
which by this process is far purer and cheaper than that ob-
tained by decomposing the nitrate of barytes, by exposing it
alone to a high temperature.

It must be observed, that we ought to prefer the employ-
ment of the muriatic or acetous acid to that of the nitric
acid ; in the first place, because the first two acids form
with barytes, salts more soluble than the nitrate, and the
washing is easier in this case : secondly, because in the so*
lution, the nitric acid, on being decomposed, oxygenates a
part of the sulphuret of barytes, and there is then a portion
of acid lost, and a part of the barytes absorbed by the sul-
phuric acid which is formed.

As to the caustic potash required in this operation, it is

#

* We may more easily obtain thd same end by pouring into the liquor
some drops of nitrate of copper or lead, by allowing the metallic sulphuret
to subside, and by filtering over again, &c.

C 4 essential

,4^ Upon ilie Preparation of pure Barytes*

essential that it should be prepared with cirbonate of potash
free from sulphate ; we may render it caustic by following
the process published by M. Descroizilles in the Annales de
Chimie^, I have frequently pursued the methods he points
out, and I have done so with increasing advantages. i

Observaiions ly one of the Editors of the Annales de Chimie
upon the foregoing Article,

I have examined the liquor of the flask transmitted by
M. Darcet along with his paper. It was more than half
filled with small white crystalline lamince; the liquor greened
strongly paper coloured with the petals of mallows. I poured
sulphuric ajcid into it in a slight excess ; there was formed
an abundant precipitate of sulphate of barytes ; at no time
was there the least smell of acetic acid. After having fil-
tered the liquor in which the precipitate was formed, I eva-
porated it in a gentle fire in a platina crucible, and it left no
traceof neutral salt. There does not remain a doubt, there-
fore, that the acetate of barytes is radically decomposed by
soda.— L. B. G.

IX. Upon the Preparation of pure Barytes.
By M. Roj?iciUETt«

In a note inserted in a late number of the Annales de Chi-
mie X, upon the decomposition of the acetate of barytes, by
means of soda, M. Darcet points out as a more ceconomical
and more certain process of procuring pure barytes, to de-
compose any barytic salt, and principally the muriate, by a
caustic alkali : I do not think the preference he gives to this
process over the generally employed one, namely, the de-
composition of the nitrate by heat, is w«ll founded. On
considering the matter in an ceconomical point of view, wc
see that in both cases we must first oi>taia a soluble salt of
barytes; that in the first wc cannot employ the liquors so

* .See Phil, Mag. vqi. x?^iii.

f Ffom Annates de Chimie, torn, Iiii. p r>i.

J See the preceding article,

much

Vpon th Preparatlbfi'^df'plTe Bar?/feL '^l

much concentrated that no barytcs remains hi solutian ; that
whatever precaution we may take in the preparation of the
'«anstic alkah by Hme, if not during the fihrations, there will
alwavs be a portion of it carbonated; consequently, the t^ame
quantity will be w:inting in the quantity of baryte^j we ouglit
to obtain: that, besides this, during its precipitation, as we
are obliged to shake the liquor, it carbonates a certain (|uah-
tity of it: that by washing also we experience a feal loss,;
and lastly, that by a hew soiutit)n in boiling water it carbo-
nates still more of it ; ' it is visible that all these subtrac-
tions united leave but a small quantity, while by the de-
composition of the nitrate we absolutely obtain 'tfate %hoTb
quantity of barytes it contains, and which amoiints to very
near the half of the weight of dry salt j and that besides, this
operation is neither difBcult nor expetisive, when we know
how to manage it properly.

Nov/ the following arc the precautions necessary to ensure
success :

Fill near two thirds of the crucible with dry and pulve-
rized nitrate ; place the crucible with its lid in a common
furnace, in a gentle heat, so as merely to melt the salt rn
Its water of crystallization; increase the fire progressively
and with caution, on account of the swelling up which
latterly takes place: when the mass, which should be then
of a cherry red/ lets no more bubbles escape, cover the cru-
cible with an inch or two of charcoal; adapt to the furnace
its dome provided with a pipe of gun metal : heat it thus for
a quarter of an hour; take the crucible from the fire; 'break
it, and pack up the barytes as quickly as possible.

I also treated by this process seven pounds* 6f iiiiraie,
which I had divided into three common crucibles and placed
in one furnace : I produced the complete decomposition in
two hours, and T obtained three pounds six ounces of per-
fectly pure barytes. But it must be observed, that if the ba-
rytes is kept too long in the fire after the decomposition of
the nitrate, it is carbonated considerably, and it is afterwards
completely impossible, whatever heat we employ, to deprive
it entirely of carbonic acid. This is the whole difficulty at-
tending my operation. I am therefore of opinion that it is
p I really

42 Upon the Comlination of the fixed Oils

really more oesonomical to extract barytes from the nitrate
by means of fire than to follow M. Darcet's process ; for,
even supposing that the quantity of barytes was equal in botJi
cases, what I have demonstrated could not exist — the price
of the potash I was obliged to employ would have cost me
almost double the expense. As to the purity of the article, as
we are obliged to manage the washings carefully, I do not
see that the process of M. Darcet merits the preference in
this respect j for it is very probable that the barytes thus
obtained should retain a little of the salt contained in the
mother water ; and, on the contrary, that extracted from
the nitrate is extremely pure, if before decomposing it we
take the precaution of calcining it slightly and redissolve it,
in order to separate a portion of the iron proceeding from
the sulphate employed.

X. Olservations upon the Combination of the fixed Oils
with the Oxides of Lead and the Alkalis, By M. Fremy,
Apothecary at Versailles*,

fccHEELE was the first who observed that the water which
serves as an intermedium, when we treat the fat oils or the
fats by litharge, retains in solution a substance to which he
has giv^ the name ef sweet principle of oils ^ because it has,
in fact, a very decided saccharine taste. But, according to.
the observation of this illustrious chemist, this water hold-
ing also in solution a certain quantity of oxide of lead, may
we not think that the taste, which suggested to him the
name of the sweet principle, proceeds from the property pos-
sessed by this metal of communicating a saccharine taste to
most of its combinations ? Where experience has demon*
Strated the contrary, would it not be interesting to inquiry
how this principle came to be formed ? What are its proper-
ties ? In what state the oil exists after having abandoned thq
principles which should have given rise to it? If this sub-
traction it) absolutely indispensable for forming the combi-

• From Annales de Chimie, torn. Ixii. p. 25.

nation

with the Oxides of Lead and the Alkalis, 43

natioa of the oil with the oxide of lead ? And upon the ex-
periments which these inquiries would produce, might we
i)ot establish the theory of one of the most important opera-
. tions of pharmacy, and the relations which its results must
have with the alkaline soaps ?

Such are the considerations which led me to the follow-
mg experiments :

I placed in a tubulated bell glass equal parts of olive oil,-
litharge, and water: I adapted to the orifice of the bell oj^ss
a tube inserted into lime water, with a bladder at the orifice
to prevent the access of the external air ; this bladder was
so disposed that I could move a spatula in the interior of the
bell glass, in order to keep the matter from sticking to the
bottom of the vessel. The mixture having been brought to
the boiling point, I saw the oxide of lead successively pass
from red to yellow, and from yellow to white. During the
time the experiment lasted carbonic acid was almost always
liberated. I allowed the apparatus to cool, in order to exa-
U)ine successively the results of this experiment.

The water which had served as the intermedium had a
strong metallic taste. When placed in contact with yeast
at ihe necessary temperature, I was never able to produce
fermentation*. It precipitated evidently by the sulphuric
acid and the hydrogen-ited sulphurets f. I passed sulphu-
retted hydrogen into it, until no more precipitate was
formed; and I filtrated it in order to separate the sulphuret
of lead.

The filtered liquor had also a very strong saccharine taste;
it was evaporated to the consistence of a syrup -, the acetate
of lead at this moment did not demonstrate the presence of
sulphuretted hydrogen. My attempts to ferment it were
equally fruitless as before the separation of the oxide of lead ;
exposed to the air, it strongly attracts its humidity ; when

f \ was for a moment led into an errqr, because I had inadvertently used
yeast, which still contained some alcohol, not having been properly washed.

•f 1 was convinced by various experiments that it was of no importance
whether in tha solution of the oxide of lead the fats or oils were rancid or
not, although Scheele thinks they should be rancid. In fact, it v/ill be seen
in the course of this paper that this circumstance is completely foreign ro
the sqlutioii.

\ projected

4 i ' Uf^h the Comlination of the fixed Oils

pt'Ojectcd upon live coals, it burns like the oils : on boiling
it with the red, yellow, and white oxides of lead, it only
dissolves the yellow one : when distilled several times with
the nilric acid, it produces in it the formation of the oxalic
acid ; when distilled in a retort in the open fire^ a part
ascends in distillation, as observed by Schcele : on increising
the fire, it gives cmpyreumatic oil as a result, acetic acid,
carbonic acid, carbonated hydrogen gas, and a slight spongy
charcoal, which does not contain any oxide of lead.

From what I have described, it is strongly to be presumed
that oil, when combined with the white oxide of lead, is no
longer in the same state as it was before this combination.

In order to separate it from this oxide J made use of the
acetic acid, because the solubility of the acetate of lead af-
forded me an easy method of separating it from the oil, the
properties of which I was about to examine.

This oil has the consistence of fat, having also the same
lancid taste : it is insoluble in water, and soluble in alcohol,
and Is precipitated by w^ater in the same way as the volatile
oils, and like these last is volatilized in part with the oil in
distillation*.

The slightest ebullition is sufficient for combining it per-
fectly with the white oxide of lead, and gives it a strong em-
plastic consistence, which does not take place with litharge
and massicot.

The yellow and white oxides of lead cannot he combined
with the common oils ; I ascertained this fact by an ebulli-
tion much stronger than if I had employed litharge.

It rejjults, therefore, from these experiments, that when
we treat the fat oils with litharge, the oxygen of the latter
carries off their carbon, and previously their hydrogen, in
order to form water and carbonic acid.

That this subtraction, rendering oxygen more abundaat
in the oils, gives rise to that saccharine s'.ibstance which
Schecle calls the sweet volatile principle of oils.

That this sweet principle differs from the mucoso-saccha-

* All tlie fat oils are dissolved in alcohol ; those, however, which have
been treaty with litharge are much more s,tropgly characterized with this
propejty.

fine

with the Oxides t)f Lead and the Alkalis, 4 J

rine by the property it possesses of dissolving the yellow-
oxide of lead 5 that its saccharine taste is independent of the
presence of the oxide ; that it differs from sugar by its vo-
la«Hty, and by the impossibility to ferment it.

That oil deprived of the principles which have given rise
to the sweet principle, and of the quantity of hydrogen and
carbon which constitutes it a fixed oil, acquires several of
the properties of the volatile oils.

Finally, that this last state of oil is the only one which
can be combined with the white oxide of lead. '

From the knowledge I have acquired of the theory'of this
combination of the oils, I did not think it right to neglect
to ascertain to what extent the opinion of several chemists
is founded, who consider the plasters as true metallic soap€.
The analogy between the plasters and the soaps can only h^
verified by observing in their respective combinations a re-
semblance in the phaenomena, or at least in the results.

I mixed some pure soap-makers' ley with olive oil ; I ex-
posed this mixture to the air under a bell glass. Eight days
afterwards there was only a slight absorption -, the soap had
still a strong alkaline taste, and the oil of this soap was not
entirely dissolved in alcohol: but at the end of six weeks
the absorption of the oxygen was complete; the soap was
very white, of a good consistenc:e ; the alkaline taste was but
feeble; diluted sulphuric acid liberated carbonic acid frouri
it ; the oil proceeding from this decomposition had the same
consistency with that from the plasters, was dissolved cold
in alcohol with the greatest facility, and was precipitated
from it by water.

I made soap in the same way as the soap-makers j I exa-
mined with the greatest care the liquor remaining afier the
operation was finished, but I could discover no trace of
sweet principle.

As the absence of this principle in the alkaline soap-ma- ;
king probably depends only upon a greater or less subtrac- ;
tion of carbon or hydrogen, and the action of oxygca
wpon oil, and the state of the oil, are ^baoluiely the same ia -
the making of.plafit,ers as ia soap-making, 1 thiuk the plas-
ters

46 Description of the Mountain Barometer *.

tcrs should be considered relatively to tlic soaps as the inso-
luble metallic salts are relative to the alkaline salts.

I am convinced that the defect in the consistency of the
soaps of potash by no means depends upon the state of the
oil, but rather upon the kind of combination ; for I never
obtained any thing but a soft soap on treating by potash
some oil proceeding from a very dry soap of soda.

Xf. Description of the Mountain Barometer , invented ly
Sir Henkt C. Englefield, Bart, F,R,S, and made hy
Mr, Thomas Jones, of Mount Street, Berkley Square,

To Mr, TillocL

X HE various advantages which are likely to be derived
from taking altitudes of every description, in a short time,
with very little trouble, and at a small expense, gives me
every reason to suppose the curious and enlightened mind
will be pleased with a description of a new portable moun-
tain barometer, contrived, and most peculiarly adapted, for
that useful purpose, by a gentleman well known in the phi-
losophical world. Its great simplicity in use, as well as
portability, renders it superior to any barometer yet made.

The celebrated experiment devised by Pascal (says the
French National Institute, in their Transactions of 1S05,)
and which proved, that a column of mercury decreased in
proportion as the barometer was carried to a greater height,
after having proved the gravity 6f the air, must have made
the mercury be considered as a scale capable of measuring
the height to which it is carried. But this scale being very
small, in comparison of the heights which it ought to mea-
sure, it was soon perceived, that it would be necessary to
improve the construction of the barometer, so far as to
render sensible and appreciable the smallest changes in the
heiirht of the mercurv. The ncccssit v of avoiding: or of cal-
culating the continued variations which the barometer ex-
periences, even without changing its place, presented an-
other obstacle, much more formidable, and which seemed

. to

Description of the Mountain Barometer. 47

to take away all hope of approaching the truth, or coming
near it : these difficulties, however, philosophers have been
able to surmount; so that barometric measures, properly
employed, may vie in exactness with the trigonometrical
measures, to which they are superior, on account of their
facility and generality of the method.

On this subject it is not necessary that I should add any-
thing further, the inventor of the instrument, of which a
drawing is herewith sent, having satisfactorily and correctly
detailed every thing connected with it, in the paper, of
which, by his desire, I send you a copy subjoined.

The paper alluded to appeared in a respectable periodical
work * nearly two years ago, but it has since been revised
and received some considerable improvements from the au-
thor, which renders its republication desirable.

I flatter myself, that the section which I have likewise
sent, of the principal and most essential improvement, will
not be unacceptable to the gentleman, nor the person who
may wish to make such an instrument, a, a, a, a, (Plate I)
represents the cistern, made of box -wood ; — c, c, c, the cover,
made of brass, which screws on, and is prevented from
being unscrewed (by idle curiosity,) by four small screws,
t. — e e represents the stem of the cistern, into which the
glass tube, n w, is firmly glued ;-— R R represents the ma-
hogany tube, in which is inserted the stem of the cistern,
where it is secured by the screws, t t, passing into it.
I am^ sir, your very humble servant,

Thomas Jones.

An expeditious Method of determining Altiitides, of every
Denomination, ivith a new portable Mountain Barometer ;
with a Description of the Instrument,

The mensuration of heights by the barometer has been,
by the labours of M. Dc Luc, sir George Shuckburgh,
general Roy, and several other scientific men, brought to
such perfection, and affords so much an easier mode of as-
certaining the elevations of the different parts of the surface

* Nicholson*s Journal.

of

4s Description of the Mounialn Barometer*

of the earth, to a considerable precision, than any other
known process, that it might have been supposed that, in
the course of thirty years, which have elapsed since this
branch of science has been perfected, a very great number
of observations would have been made, and the heights of
almost the whole surface of our own country ascertained by
the numerous travellers who continually traverse it. The
contrary is however the case; and the small number of ob-
servations of this kind may be attributed to several causes.

The instruments are of considerable expense, and, from
their complicated construction, easily liable to be out of
order in the course of a long journey.

The observ^atifens themselves, though each not taking up
any very long time, yet, when multiplied on every hill and
valley, as they ought to be, for the purpose of obtaining a
just idea of the face of the country surveyed, in the aggre-
gate consume much of the traveller's time; and the consvtant
unpacking and re-packing the instrument, becomes a greater
labour than our natural indolence easily submits to.

It has moreover been generally supposed, that two instru*
ments and two observers making simultaneous observations
at the upper and lower stations of the height to be measured,
are indispensably necessary. This, of course, would put it
out of the power of a solitary traveller to make any obser-5^
v^tions at all.

Whether from these, or other causes, the fact is, that
whoever reads the numerous Tours, Surveys, and Reports
of the different parts of our island, published within these
last twenty years, and many of them professedly with a view
to science, either of agriculture, mineralogy, or geology,
will be perpetually disappointed, by meeting with mere
guesses at the elevations of the tracts of country described :
though a knowledge of those elevations is almost indispen-
sable to the geologist, mineralogist, and military surveyor; ,
highly iiseful to the scientific agrictdtiirist, and very inter-
esting to every one, who, from mere motives of enlarged
and enlightened curiosity, rends books of travels, or cm-
ploys his own leisure in traversing the countries described by
other voyagers.

I cannot.

Description of the Moujil am Barometer, 40

I cannot, therefore, but hope, by simplifying the baro-
meter, and thereby rendering the instrument much less ex-
pensive, and its u?e at the same time more easy, and show-
ing that very considerable accuracy n)ay be attained by a
single observer, this most useful branch of science may be
cultivated, to so great an extent, that, in the course of a
few years, we may have almost as perfect an idea of the re-
lative heights CrF the dilfercnt j)arts of IJngland, as we now
have of their horizontal di/tance.

A barometer, nearly similar to that which I am now
about to describe, was constructed, several years since, by
Dr. Hugh Hamilton, and is by him dcseribed at large in
the fifth volume of the Transactions of the Irish Academy.
I saw the instrument, in his hands, nearly seventeen years
ago, and was much pleased with its performance. I do not
know, however, that any more were then made. I have
lately coustructcd the barometer, whose description I shall
now give, which is still more simple than Dr. Hamilton's,
and much cheaper, and which, in many trials I have made
of it, appears tO' unite solidity, lightness, and ease of ob-
servation, to as great a degree as can be wished.

The barometer lube is about 33 j inches in length ; its
bore is a teaih of an inch in diameter, and its external di-
ameter is three-tenths of an ir.ch. This sized bore is fullv
suflicient to allow the free motion of the mercury*. Tlie
\Mstern is of box-wood, turned truly cylindrical, 'aiid is one
inch in its external diameter, and an inch in depth; a short
stem projects from its lop (the instrument being in a posi-
tion for making an observation), for the purpose of giving
a firmer hold to the tube : this stem is perforated \yiih a
hole sufficiently large to admit the tube, which is glued to
it in the usual mode. The ttibe projects into the cistern
i

* Several barometers haveliecn lately constructed by Mr. Jones, with the
lower part of tlic tube only a iwe.itietfi of ;ui incti in bore, something on tlie
principle of the marine barometers. This alteration was made because ia
some few instances when very carelessly used, air had {^ot into the tube. In
the form now adopted, this defect seems compk-tely remedied, and the mo-
tion of the mercury, thonj^h full free enough for accuracy, »<> rendered so
equable, that observations in a carnage are much easier. 1 therefore, on the ■
wliolc, prefer this construction.

Vol. so; No. 117. Feb, 1608. D exactly

50 Description of the Mountain Barometer,

exactly^p half its depth. The bottom of the cistern is closed
by a strong lid of box, which screws on the cistern, and,
pressing against a leather glued to the inside of the lid, ren-
ders the whole perfectly impervious to the mercury in every
position. The tube being filled and boiled in the common
way, and the instrument held inverted in a perpendicular
position, mercury is poured into the cistern till it is filled
within two-tenths of an inch of the top. The lid is then
firmly screwed on, and secured from being opened, (by idle
curiosity,) by a small screw passing through its side. The
essential part of the instrument is now finished. The end
of the tube, in the cistern, can never be uncovered by the
mercury in any possible position, and, of course, no *air can
ever enter into it; and, as the areas of the cistern and tube
are as the square of the diameters, the diameter of the bore
of the tube being -1, its external diameter -3, and the di-
ameter of the cistern I'O, the area of the cistern is 100 — 9 91,
and there beins; two-tenths of an inch left empty in the cis-
tern, the mercury must fall ISS-tenths, or 18 inches and
two-tenths, before the cistern is quite full ; a space adequate
to the measure of greater heights than any known mountain
on the earth, much more to that of any height in this coun-
try. It- will not easily be believed, by those who have not
seen it, that the air will act on a cistern thus completely
closed,- and of which the wood, in its thinnest part, is above
a quarter of an inch in thickness ; but the fact is, that even
wlien the pores of the box wood are closed by thick varnish
(except in that part which touches the mahogany tube,) in
order to-prevent the wood from being affected by damp, the
mercury, on turning up the barometer, takes its level almost
instantaneously, certainly in less than haU" a minute; and
that, when the instrument is suspended by the side of the
best mountain barometer, ofKamsucn's construction, with
an open cistern, no difference whatever can be perceived in
theirsensibility to the variations of the atmosphere. It is
•obvious that the variations of altitude in this instrument, its
dimensions being as above stated, will be one ninety-first
part less than, in a barometer furnished with an apparaius for
bringing the surface of the mercury-.in the cistern to a C\Ktd
C ' .. . level:

Desci'iptidn of the Moimtain Barometer. 5 i

level : this defect might be remedied by dividing the scale ac-
cordingly ; but it is much more convenient to divide the scale
to real inches, and make the necessary allowance in the result*

The tube and cistern being thus prepared, are mounted iil
a mahogany tube or frame of the size of a common walking-
f?tick. The stem of the cistern goes into the mahogany
tube, and is there secured by a piece of brass tube, which
fits to the cistern and mahogany frame to which it is screw-
ed ; or the stem may be on the outside, cut into a malti
screw, and so be screwed into the mahogany tube. The
tube is secured in the mahogany case by passing through per-
forated corks in the usual way.

For the observation of the height of the mercury, two
Opposite slits are cut in the mahogany tube, reaching from
about 32 to 20 inches for the long scales; /and 32 to 25
inches for the short ones ; which are sufficiently long for
any purpose in this country. The front slit has its sides
bevelled, and is, exteriorly, about three- fourths of an inch
wide 3 on one side is fixed a brass scale, divided as usual to
inches, tenths, and twentieths. On this scale a nonius
slides, moveable by a small knob, which reads off, as in
other barometers^ to 500th of an inch. To this nonius a
small portion of brass tube is attached, which embraces
the barometer tube, and its ld\ver edge is, in observation,
made a tangent to the convex surface of the mercury, as
in other well -constructed barometers ; and the very narrow
slit behind gives abundant light for observation.

On the bevelled side of the front slit, opposite the scale,
a thermometer is placed for taking the heat of the instru-
tnent ; and there is room for the scale of correction, placed
on Ramsden's attached thermometers, as wellas Fahrenheit^
scale. This thermometer is so contrived as to take out of its
place, and answers the purpose of the attached and detached
thermometer.

A thin brass tube, \Vith slits in it, turns half round, on
two pins, in the usual manner, and covers the apertures
above described in the mahogany tube when the barometer
is not in use.

The mahogany tube is made rathet tapering, and with a
i> 2 ferrule

52 Descr'iption of the Mountain Barometer,

ferrule at the end opposite the cistern. This ferrule un-
screws^ and shows a steel ring, by which the barometer may
be suspended when convenient.

Along tlie mahogany tube is a scale of feet, carefully
divided to inches ; the feet being accurately laid down by
small dots, on the heads of brass pins, sunk into the wood.
A scale of this kind is alw.iys convenient, and may often be
of great use.

To those travellers whose pursuits may lead them to the
measures of the higher class of mountains, I would venture
to recommend a barometer constructed with a tube of tv/o
feet lonaj onlv : so that the whole instrument should not
much exceed t!5 inches in length. This barometer would
not of course be useful until the mercury fell below 24
inches, which would be at a height of about 6000 feet in
the atnxosphere : but its great portability into regions where
from both the difficulties of the path, and the rarity of the
air breathed, every ounce of incumbrance becomes a serious
evil ; and moreover, the great security to the instrument
itself arising from its shortness, would, I am persuaded,
render it well worth 'while to carry such instruments where
great altitudes are to be measured; and it is to be remem-
bered that the instrument loses no part of its accuracy when
it once comes into action, by being thus shortened.

Having thus described the instrument, a few practical
remarks on the manner of using it may not be superfluous.

When I am about to make an observatfon, about five
minutes before I arrive at the place I take out the thermo-
meter, holding it by the upper end at nearly arm's length
from my body, and, if the sqn shines, xyi the shade of mv
person, fi very soon takes the temperature of the air, and
Is not sensibly aff"ected by the heat of the hand. The heat
being observed and written down, the barometer is luriied
up ; the brass tube half turned ; and the instrument held be-
t'.veen the finger and thumb of the left hand aboue the slit,
so as to let it hang freely in a perpendicular position. Few
persons, if any, have sufficient steadiness of hand to pre-
vent little vibrations in the mercury in this position : the
hand, therefore, should be either rested against any fixed

body,

Description of the Mountain Barometer: 53

bodv, or, ir no such occurs, by kneeling on one knee. The
cistern sliould be let down so as to touch the ground, the
left hand holding the barometer in a vertical position, which
a little practice will render very easy. The index must then
be moved by the knob till its under surface, as before stated,
is tangent to the mercury. A few light taps should be given
to the tube, to ascertain that the mercury has fallen as low
as it can. The height being then read off and registered,
together with that of the attached thermometer, tiie brass
tube is turned back, so as to cover the slits ; the instrument
gently inverted, and the whyle is finished. All this may be
done in two minutes.

It may not he improper here to add, that I have found
by experience that it is not necessary to quit the chaise in
order to make observations with this b-trometer; it is only
requisite for the horses to stand still. The thermometer, if
held at arm's length out of the chaise window, v»-ili give the
temperature exactly, before the order is given to slop the
carriasfe: and the delav to the traveller will not much ex-
ceed a minute, as the observation may be read off and writ-
ten down while the carriage is again going on.

The most convenient mode for deducino; the heiizhts from
the barometrical observations is, certainly, by the common
logarithmic tables ; and it is unnecessary here to detail tlie
method, wliieh may be found in nunjcrous hooks. It is,
however, necessary for this method to carry the tables of lo-
garithms, which is sometimes inconvenient. Tlie engraved
table formed by Mr. Ramsden is on a single narrow sheet,
and extremely portable, besides being very easy in its use;
but it may be lost or mislaid when wanted. Several inge-
nious formulce have been devised, which 'niciy either be en-
graven on the instrument itself, or committed to memory.
Of the former, sir Georgx; Shuekburgh has given a very con-
cise one, in his second paper on the measurement of heights
by the barometer, in the (3Sth volume of the Philosophical
Transactions ; and Mr. Professor Leslie has invented a very
elegant one of the latter sort ; but these, though very simple
in form, require a considerable number of figures in the ope-
ration, and are, on that account, inconvenient. For the

D 3 purpose.

54 Description of the Mountain Barometer^

purpose, therefore, of computing on the spot, and very near
to the truth, any observations made on a journey, and that,
almost without the necessity of writing at all, I have caused
the following short table to be engraven on the scale of the
barometer. It expresses the value of the difference of the
tenth of an inch in the height of the mercury at the tempe-
rature of freezing, in English feet.

Feet.

Q2 '

91

90

89

SB
S7
86
85
84
83
82
81

The method of using it is as follows : — 1st, Add the two
observed heights of the barometer, and halve the sum to
obtain the mean height. 2d, Subtract the lesser height
from the greater, the remainder is of course the difference
of height in tenths, &c. of an inch. 3d, Enter the table
with the mean height, and take out the feet answering to it,
making a proportion, if the mean heiglu does not exactly
answer to a foot. (This proportion may be made bv head.)
Multiply the number thus obtained by the tenths. Sec. of
an inch of difference of height. The result will be nearly
the nunibcr of feet, answering to the difference of height be-
tween the two barometers at the temperature of freezing.
When the lower barometer stands between 29 and 30 inches,
and the elevation docs not exceed 1500 feet, this rule will
give the height wiihin one foot of the result from the loga^
rithniic method. When the elevation is about 3000 feet,
the error will be nearly three feet, and at heights greater
than 2000 feet, the error increases in a higher ratio. It is
^Iwavs in defect. In this country, however, such eleyations

do

Inches.

Feet.

Inches.

Feet.

Inches.

Feet. 1

Inches.

20-05

130

22-25

117

25-05

104

28-35

'20

129

-45

116

•30

103 j

'Q5

•35

128

•65

115

'55

102

•93

•50

127

•85

114

•80

101

29-27

•66

126

23-05

113

26-05

100

•61

•82

125

•?5

112

•30

99 1

-95

21-00

124

•45

111

'57

98

30-30

•18

123

•65

no

•85

97 !

•65

•35

122

•87

109

27-15

QQ !

31 '00

•53

121

24-10

108

•45

95

'37

•70

120

-32

107

•75

94

•75

•87

119

^55

106

28-05

93

32-10

?2-05

lis

•sp

105

Description of the Mount am ^arimeier . i;^

do not exist ; and in., those parts where a knowledge of the
comparative heights of the difterent hills is the most gene-
rally useful, they seldom exceed 1000 feet ; at all events,
such observations as relate to great elevations may be alvyjLye
recomputed. by more rigorous methods at leisure.

The correction of the heights thus obtained, for the tepi-
perature,of,.th9 air above freezing, is by sir George Shuck-
burgh SLipposed to be as the height of the thermometer, and
to be 2-44 thousandth of the approximate height for each
degree of Fahrenheit, additive when the temperature is above
freezing, and subtractive when below freezing. General
Roy's, observations and experiments lead to a supposition
tl^>t|.^h9;icp;:Tection is not exactly as the height of the ther-
mometer, and that at about the temperature of 50 degrees
it amounts to 2*3 — thousandths, and is less, both much
above and much below that temperature. For the purpose
of immediate computation, I take the correction at 2*5,-
which, though certainly rather too great, will in general be
productive of very small error, and affords a rule which is
easily remembered and quickly applied. It is this ;

For every four degrees that the mean temperature of the
two detached thermometers exceeds 32 degrees, add one
hundredth of the approximate height, as before obtained,
to it ; for every 40 degrees one tenth, and so for any greater
or lesser number of degrees. * ,

I have not hitherto mentioned the correction, which i-n
fact ought to be the first in order, viz. that i'or the differ-
ence of temperature of the- t^vo baromelers themselves : but
this cbfrection is in general so small, ^s"' to be safely neg-
lected. Should it, howev^er, be thought necessary to apply
it in this approximate method of coniputing heights, the
rule deduced^ from sir George Shuckbui^gh's mtfthod'^r'^^ate

follows, and it wants no'-t4ble, thou^^h be "h^^ gl'i^eti^'8&
^•qj. j^^ \ ■ /HfiMiO'' . U id tk:v'. li^*' ■ ■'■ •■ ■.

3 ''When the barometer slihds at 2i[> inche^'^ tfier expansrdh
of the mercury for one degree of Fahrenheit is two-thou-
sandth of aTi inch, when it stands at 30 inches it is three-
thousandths, and for the intermediate inches it increases (f^-

D 4 actly

56 Description of the Mountain Barometer,

actly as the height of the mercury; that is, at 21 inchc? it
is 'OOiJl, at 22 inches '00^2, and so on; so that the height
in inches is the number of ttni thousanchhs oF expansion for
one degree of Fahrenheit. This is very easily remembered.
The expansion for any other number of degrees is in propor-
tion to the degrees themselves ; that is, for two degrees it is
twice as much, for ten degrees ten times as much, and so
on. Take therefore the difference oF height of the attached
thennomelers at the two stations, and multiply the expan-
sion for one degree at the coldest barometer (which will al-
most always be the one at the highest station) by the num-
ber of degrees of difference between the heal of the two ba-
rometers, and add the quantity to the observed height of the
coldest barometer, and it is corrected for the expansion of
the mcrcuj-y by the heat of the instrument.
An example will make the whole clear.

Inche-'!. Therm, attached.

Observation at bottom 29*400 - 50^
Observation at top - 25*190 - AG

Difference 4

Expansion for 1® at 25 inches - '0025
Multiply by difference - - 4

•0100

One hundredth of an inch is therefore to be added to the
observed height of the upper barometer 25*190, so the cor-
rected height is 25*200. It is, however_, to be observed, that
the application of this correction is of doubtful accuracv in
practice; as it is by no means certain that the attached ther-
mometer, be it placed where it may in the mounting, will
give the real heat of the column of mercury in the barome-
ter, and therefore I had at first paid that it niight on the
whole, in general practice, be neglected. If much accuracy
•is wished, and time permits, the surest way is*to leave the
barometer in the shade so long as for the whole inslrumeut

to

Description of the Mountain Barometer. 57

to acquire the temperature of the air, and then to make this
correction according to the rule given above, from the dif-
ference of the two detached ther77iomctcrs ; and this baro-
meter, from the lightness of its mounting, will have the
advantage of taking the temperature oF the air sooner than
those formerly made with solid wooden cases.

It may not be improper to give an example of the method
already detailed.

Observation at bottom 29*400 Therm, in air 45
. at top - 25.200 Therm, in air 41

2 I 54-600 2 I SQ

Mea^ - 27*300 Mean heat - 43

Standard - 32

Difference - 42 tenths —

Value of a tenth by the table 95*5 feet. Difference J 1

1910
3820

Approximate height - 4011-0 feet
Do. by sir G. Shuckburgh 401 6-0

Error - 5 feet

Correction for Temperature.

For 8° = 2 hundredths - - 80 feet
For 3** = 3 four hundredths - 30

Correction -f 110
Ditto by sir G. Shuckburgh - 107*4 ^

Error -j- 2-6

Approximate height by me 4011 By Sir G. $. 4016
Correction for temperature 110 107*4

Result - 4121 4123-4

Example

58 Description of the Mounlain Barometer,

Example second.

Observation at bcttbm 30*017 Thertn. M'dif" 60**

., at top - 29 334 Therm, m air 37

2 I 59-331
Mean - 29*773
Difference 4*83
Value of a tenth by
• the table

} . ^^*'

330*0
70-00

2-623

Approximate height - ^422*623
Ditto by G. Shuckbiirgh ~422*9

2 1 JI7 '

Mean -

- 38*5

Standard

- 32

DiiFerence

- 26*5

,

Error

00 3

2 =

Correction for. Temperaiure.
For 24° = 6 hundredths - -
2 four hundredths -
1* eight hundredth -

Correction +
Ditto by sir G, S.

Error

i!];^:

23*3
2*0
0-3

27*8
27-2

0*6

Approximate height by nje 422-6
Correction for temperature + 27-8

By sir G. S. 422*9

27*2

430-4

430-1

These two examples show how near the truth tlie method
here recommended will come, even in considerable heights.;

It has- been already observed, that in observations made
with the barometer I have described, a small correction is
necessary on account of the rise of the mercury in the cis-
(ern^ as the barometer falls. Altitudes being in all cases

measured

Description of the Mountain Barometer. 5^

measured by the differences of the heights of the mercury at
the two stations, and these differences being evidently al-
ways too small in this barometer, the correction is obviously
always additive. As in constructing different barometers,
the interior and exterior diameters of the tube will not al-
ways be exactly similar, though the cisterns may be turned
always alike ; this error, and of course the correction for it^
should be in each instrument deduced from a comparison
with a barometer of known accuracy at different heights, .
It will probably vary in different instruments from a nine-
tieth to a seventieth. Indeed, if it were always taken at an
eightieth, in instruments constructed as above directed, the
possible error could only amount to about one foot on a
thousand ; a quantity of very little importance.

It now remains to say a few words o« the necessity of
two barometers for the mensuration of heights, and the pro-
bable error to be incurred by using a single one. There is
no doubt, that when very great accuracy is required, two
barometers ought to be used ; but even with every precau-
tion, altitudes cannot be taken by barometers sufficiently
near for the purpose of carrying water, either by pipes or
canals ; and for the purpose of the geologist, military sur-
veyor, or agriculturist, it is of very little importance whe-
ther a mountain is 1000 or 1010 feet high, though it is of
the highest utility that he should know whether it is 800 or
1000. I have, during the course oF many years, been in
the hai)it of taking observations of altitudes by a single ba-
rometer, and have had many opportunities of repeating my
observations on the same hills when the barometer has been
at different heights, and either falling or rising during the
time of observation ; and more than once I have observed
heights which had been trigonometrical ly taken by the best
instruments; and I can safely say that the difference be-
tween these observations has seldom amounicd to so much
as two feet on a hundred. The mode I use is this : — At
setting out, I take the height of the mercury, and note the
iinie of observation ; \ likewise note the time of the second
observation, and on returning to the first station, observe

again,
3

Co Description of the Mounta'm Barometer.

again, and note the time. IF the baromelcr has altered in
the interval, a simple proportion eoirects cither oi" the three
observations, and reduces the height to what would have
(>ccn observed had the nicrenry been stationary. . It is true
that this method supposes the motion of the mercury to have
been uniform during the interval of observation ; but except
in very variable weather, wliich does not often occur, par-
ticularly in summer, when the greater numl)er of these ob-
servations will naturally be made, this supposition is liable
to but small error. It is also true, that a traveller has often
jio opportunity of making a second observation at the spot
he sets out from. Even in this case, a near ap[)roximatiou
^nay oflen be made by observing, for example, at a stream
on eueh side of the hill to be measured. Jf also he observes
the barometer repeatedly in the morning before he sets out,
and sets its tendency, and does the same at every halt, during
the day, he will have data whereon to found a nearly accu-
rate correction. But if all tliis should be out of his power,
even under the most unfavourable circumstances, barome-
trical obi«crvations will give a much more accurate idea of
the outline of a country than any we now ptjssess; and it
should be ever remembered, that observations though defec-
tive, if carefully made, and faithfully recorded, are valua!)le,
and if repeated by diflerent travellers the errors vvill, in most
cases, compensate each other, and from the whole very ac-
curate conclusions may be drawn.

I have entered into a greater detail than would be neces-
sary for a greater part of your readers, in the liope of being
intelligible to those who are less acquainted wiih the sub-
ject, and who may wish to employ any instrument-maker
for the construction of barometers sinular to that which I
have described.

Injustice to a very ingenious young artist, permit me.to
add, that I h:i,ve employed in making those which 1 have,
Mr. Thomas Jones, of No. li?4, Mount-street, Berktlcy-
fcqnare (pupil of the late Mr. Kamsden), and who makes
them complete at the price of three iz;uineas and a half, wiih
^ short scale reading from 25 to 31 inches 3 and four gui- '
'i neas

Description of the Mountain Barometer, 61

ncas for those with a long iscale reading from 20 to 31

inches.

I am, sir, your humble servant,

H. C. Englefield.

P. S. On comparing several havoiiieters made by Mr. Thomas
Jones, since this description was .first written, I find that in
some of them ihc mercury does not take its true height on
turning up the instrument, quite so quick as in the two
which he first constructed for me. This difference is owing;
to the greater closeness of fibre in some pieces of box wood
than in others, but it does not affect the accuracy of the in-
strument. In order to give a quicker action to these baro-
meters I advised Mr. Jones to bore a small hole or two in
these cisterns, and insert a j)in of open grained wood into
them. This answered perfectly well; but a curious circum-
stance occurred : when deal or willow wood pins were in-
serted, the mercury, when shaken for some time, passed
through the pores of these woods in the form of a fine black
powder, and it was necessary to substitule ashen pins to
confine it in the cistern. It may not be superfluous to say,
ihcit the weight of this barom(;ter is less than a pound and
a half. The weight of Ramsden's last improved barometer
' is 44" pounds, and that of his earliest about G';- pounds. [
subjoin a few observations by which the accuracy of this
barometer may be fairly estimated.

On R'lclnnond HilL

iSOfT. Barom. T.herm. Results.

Jan. 1, Hill top - - 29'540 44
Thames* side 2i)-68G

Feet.
- 133

134

*

•14G

- >

Jan. 2,

IliUtop - -

29-708

38

Thames' side

29-8f)0

•152

- -

Jan. 31,

Hill top - -

29-301

36

Than^es' side

29*453

37

'i5i - ... 137

Feb,

62 On the Means of gaining Power in Mechanics.

Barom. Therm. Results.
Feb* 23, Hill top - - * - - 29*758 51
Thames* side - - - 29*912

Feet.

•154 139*

Feb. 24, Hill top - - - - -« 30*180 53
Thames* side - - - 30-334 54

• 154 - - . . HO

On the Signal Hill at Bright helmsf on*
In 1796 with a barometer of Ramsden*s.
Signal House above High water mark - • 4 Id
In 1806, with my barometer ^ * - - - 403

416
418

Devil's Dyke, near Brigkfhehnston,
In 17S85 with a barometer of Ramsden's - -^ 697
In I8O6, with my barometer ----- 695

Lord Ahercorn*s Lodge, at Staimiore, above the Strearft
in Ed g ware Town,

Feet.

Jan. 3, ----- 306
Jan. 7, - - - ^ - 306

The observations from which this height was deducec^^
were made in the chaise, both on Jan. 3 and 7.

XII. On E. V.'s Article '^ On the Means of gaining Power
in Mechanics^*

To Mr, Tilloch,
sin,
J\ coRRESPONDENNT asserts in your Magazine for last
month*, that he has a machine with which, by the appli-
cation of 2lb. descending through three h^it, he raises 20lb*
through two feet. He wishes to have some person's opi-
nion of it through the same medium. You possibly may

* Phil. Mag. Vv>l.ixlx. p. 351.

have

On the Means of gaining Tower in Mechanics, 63

have many ; and on so extraordinary an assertion, I could
not forbear giving mine.

As the gentleman has neither given a description nor
drawing of his machine, it is impossible to give any other
opinion of it than a general one, and that must be against
it: for it is not very likely that the gentleman should haVe
discovered any latent property in the mechanical powers;
^ince they have been tried in so many different ways and
forms, and by so many ingenious persons, that, had there
been such latent power, surely some of them would have
discovered it. But they have hitherto found, that these
powers act according to certain Immutable laws, beyond
which, not one jot can they be forced. The mechanical
powers, by a little consideration, may all be reduced to the
effect of a lever, or a combination of levers ; and I can,
with safety, affirm that the lever possesses no such powder as
that which he attributes to his machine.
. I should limit this last expression a little, for I do not
attempt to deny what he so positively asserts, but this I can
with equal confidence assert ; that though his machine may
perform as above related, it is impossible that it should con-
tinue to do so ; that is, ihat it should continue to produce
a rotary motion, with that power with which it set out.
It must sooner or later come to a state of rest, and will then
require as much external power to restore the machine to
its former state, as it had apparently gained power beyond
the laws of mechanics, by its first eflbrt. Then where ,is^.
the advantage of the machine ?

If the geiulemaii would be so obliging as to favour us
with a -drawing and description of his machine, we may
judge of the fact much better ; and if it convinces the world
of its great power, and overturns my argument, it will very
much improve my knowledge in mechanics, and I shall
•yery gladly subscribe myself

his much obliged humble servant,

T. SWANWICK.

Commercial Acr.dcmy,
Derby, February 17, 180S.

:KIII. Ea-

C 61 ]

Xin. Exfract of a Memoir upon the Products which result
from the Action of the Metatllc Muriates, the Ory-mn-
riatic Jgid, and the. Acetic Acid, upon AlcohoL By
M. Thknakd*.

^Vl. TiiKNAiiD demonstrates in this memoir, that the me-
tallic muriates form with alcohol only a very small quantity
of ether J that this ether, which is at first dissolved in
a great quantity of alcohol, may be separated from it by a
gentle heat in the form of gas, jiarticularly by means of
warm water, which seizes upon the alcoholic part, and puts
the ethcratcd part at liberty to a certain point ; that this
ethereatcd gas has a very great analogy to that obtained with
the muriatic acid and alcohol ; that in both cases it has the
same smell and taste, the same solubility in water, the same
maimer of burning with a green tlame diffusing vapours of
the muriatic acid, although before the combustion no re-
agent indicated the presence of the gases ; in short, that they
only differ from each other bv the etherated muriatic gas
not liquefying, except at a heat of 12*5 of the centigrade
thermometer, while the other becomes liquid at + )G*5.
This difference being very slight, M. Thenard thinks we can
no longer hesitate to acknowledge the nature and mode of
formation to be the same in both : thus in the metallic muri*
ntes, it is only the excess of acid which aces upon the alcohol,
Sec. that for this reason alcohol cannot be converted into ether
except by a great quantity of metallic muriate, and that this
cor. version is the easier, the greater excess of acid the mu-
riate contains, and the more it is soluble in alcohol : the
muriate of tin therefore will succeed better in this operation
than anv other. In all cases the oxide of the muriate is not
de-oxid.ited, and a portion only of this oxide is precipitated.
IVoceedine to consider the Action of the oxy-muriatic acid
upon alcohol, he shows that in the re-action of these two
bodies upon each other, v/hich is very brisk, almost all the
oxy-muriatic acid is decon^posed, and that much water is
produced, plenty of nmriatic acid, undecomposed akoho).

* From ylnn. de Ckimic, tom. ixi. p. 308*

a great

Action of t lie Metallic Muriates, ' &c, upon Alcohol, 'G5

a great quantity of oily matter thicker than water, having a
cool taste ftke mint, and a peculiar smell completely diffe-
rent from that of ether : further, a small quantity of car-
bonic acid, a matter easily charred, and prohably acetous
acid, but no ether : — ^that the oxy-muriatic ether of Scheele
is merely muriatic ether properly so called, when made of
a mixture of alcohol, muriatic acid, and black oxide of
manganese; or of muriatic ether and sulphuric ether, when
made with the black oxfde of manganese, sea -salt, alcohol,
and sulphuric acid : — that Pelletier's is also of this nature,
since he made it by using the foregoing mixture ; and that
the oxy-muriatic ether said to be obtained by passing the
oxy-muriatic acid through alcohol, is nothing else than a
solution in alcohol of a greater or less quantity of oily mat-
ter. We may even separate the oil from the latter by
means of water, and we re-form it all at once by dissolving
this oil in a determinate quantity of alcohol.

The novelty in this part of the author's labours does not
consist in this formation of oily matter, water, acetous
acid, &c. ; for Scheeic, in his Memoires de Chimie, speaks of
the oily matter ; and M. Berthollet, in the Memoires de
I'Academie for 1783, speaks of this matter, and besides of
water, acetous acid, &c., as produced in this operation*
M. Thenard's claim to novelty consists in his having proved*
that the oxy-muriatic acid could not with alcohol form
ether; and he has explained why Scheele and so many other
chemists happened to obtain it.

In the last place, being anxious to examine the formation
of the acetic ether, M. Thenard mixed together 120 gram-
mes of highly concentrated alcohol, and 120 parts of
acetic acid, of an acidity determined by the quantity of pot-
ash required by this acid for its saturation; he distilled this
mixture, cohobated it twelve times, and thus sensibly de-
composed the whole of the alcohol employed, and 66' \Q
grammes of acetic acid, representing 32 grammes of dry

* M. Berthollet, in the Memoires de VAcadcmie for 1785, has even an*
nounced that the muriatic acid and alcohol produce but very little ether ;
and we may perceive that he is inclined to regard this small q^uantity of ether
-as foreign to the re-action of these two bodies.

Vol. 30. No. 117. Fel, 1808. E acid,

€6 On a peculiar Property in Camphorated IVdter,

acid, or as it exists in the acetite of potash well melted.
About 1 20 grammes only of acetic ether were formed, how-
ever, although no gas was liberated ; and the operation when,
terminated presented a loss of seveii grammes only : from
this M. Thenafd is led to think that a portion of the oxygen
of the acetic acid is combined with a portion of the hydro-
gen of the alcohol, while the other principles of the acid and
those of the alcohol unite to constitute ether. Otherwise, if
no water w.^s formed, it would be necessary, in order to ac-
<;ount for this operation, to admit that the best rectified al-
cohol contains nearly one-fifth of its weight of water, which
is scarcely probable. This ether has a pleasant smell of
ether and acetic acid, and yet it neither reddens turnsole
tincture nor turnsole paper; it has a taste peculiar to itself,
and very different from that of alcohol. Neither its specific
gravity nor its tenuity, has been as yet exactly taken ; all
we know is, that it is lighter than water, as it floats above it,
and more turbid than alcohol. Water seems to dissolve
more of it than of the sulphuric ether. It burns with a yel-
lowish white flame, producing an acid, which is probably the
acetic. FinaUy, in a sealed flask, it does not seem to alter
upon standing for a length of time ; at least M. Thenard
had a six months experience on this point,

XIV. Upon a peculiar Vroperty in Camphorated Water.
By M. Cadet*.

JL HREE years ago a surgeon in Madrid announced that the
carbonic acid favoured the solution of camphor in water,
and that the water had very remarkable medicinal properties
In diseases of the bladder. Leaving it to physicians to
judge of this matter, I was merely desirous of ascertaining
the chemical fact. I made a solution of camphor in distilled
water, and another in water saturated with carbonic acid
by Mr. Paul's method, in order to estimate the quantity of
camphor dissolved. I weighed the camphor before and after
the solution, and I found that the distilled water had ab-
sorbed 1 6 grains of it per pint, and the carbonic acid only

* 'StomAmtt'di Chimict torn, Ixil. p. 132,

' ' 15 grains.

On the Coviet of \SOf\ 6f

15 grains* As I had been obliged to filter the liquors and
to dry the filters, I thought that the camphor not dissolved
must have lost its weight by evaporation, and that the ba-*
lance did not give me the just quantity absorbed by the
water ; I therefore sought for a reagent, which evinced to
me the presence of camphor in the water. -.»

I found that potash precipitated the camphorated wat«r^
while soda or ammonia did not affect it; i^ut the potash
must be pure and caustic. If it contains carbonic acid, it
docs not precipitate the can^phor ; and if after having pr^*
4ipitated it we expose the vessel to the air, the liquor absorb*
ing carbonic acid resumes its transparency. w/vi ::d

Here, therefore, is a new method of distinguishing^jjbt-
ash from soda. Camphorated water is in this respect A
more certain reagent than the nitro-muriate of platina, and
more easily procured. But the metallic salt is more con-
venient, as it precipitates the carbonate of potash.

On trymg by caustic potash camphorated water charged
1^'ith carbonic acid, I obtained no precipitate, except by put-
litig in a great excess of alkali : this precipitate did not seem
to be greater than tliat obtained in distilled water. I think|
therefore, . that carbonic acid does not sensibly favour the
Solution of camphor in water ; but it at least results from
these experiments, that the water does not merely charge
itself with the aroma of the camphor, as some chemists think,
and that this concrete volatile oil is dissolved in a proportion
lufficient for the purposes to which it is applied. When
the camphor is reduced very small by trituration with some
drops of alcohol, water takes up more of it than 1 6 grains
fet pint, and some chemists have dissolved even 30 grains.

XV. Letter from Gavin Lowe, E^q., on the Comet
of 1807.

To Mr, TilhcL

JL HE comet that made its appearance about the latter 6nd
of last September, and continued visible during the thretf
Succeeding months, has no doubt been carefully and ^issi-
duously observed by the astronomers, not only ia this coim-

K 2 ^ uy.

^8 ^ On the Comet of 1 807.

try, but by many others in different parts of the world ; aa
that the elements of its orbit will be ascertained with great
precision.

I had an opportunity of observing it fourteen times be-
tween the 4th of October and the 12th of November, but
none afterwards. The right ascensions and declinations were
corrected for refraction, and from them the geocentric longi-
tudes and latitudes were deduced. With these data I eoia-
puted the elements of the orbit according to the rules laid
down in sir Henry Englefield's excellent Treatise upon Co-
mets, and hope that, though not quite accurate, they will not
be found to err much.

The drawing (see Fig.) represents the comet's orbit simply
applied to, but not projected on the plane of the ecliptic.
The outer circle t> 25,=^, "l^, is drawn at pleasure with
any radius. — A B C D is the earth's, and E V F part of the
comet's orbit : X S V its axis : © gj the line of nodes ;
V the perihelion point, and S V the perihelion distance.

The elements of the orbit are nearly as follows : The
perihelion distance = 0-64802; the distance of the earth
from the sun S A or S B being = 1*00000.

The time of the comet's passing the perihelion at V wa^
September 1 8th, 22 hours 10 minutes M. T.

The longitude of V on the orbit was 28° 4l' in Scospio.

The longitude of the ascending node 26° 3(5' in Sagit-
tarius.

The comet passed the ascending node September 29th,
18*^48'".

The longitude of the axis S X as seen from the sun,, was
in 13° 11' af Gemini; and its elevation or north latitude
24° 43'. — The inclination of the orbit 63° 15': — this is
easily conceived, by supposing the visible part of the orbit
from n to F to revolve upon the line of nodes gj n till any
point in the orbit, as F, is elevated 63^-° above the plane of
the ecliptic.

The comet was seen here soon after it passed V; the earth
at that time was nearly at A, moving from thence towards B ;
while at the same time the comet moved from V towards
F ; and consequently its motion was direct.

On the Comet of 1807. ^9

Owing to the oblique position of the axis, it was impos-
Tsible to see the comet in the inferior part of its orbit E V,
on its approach to the perihelion.

I ara, sir, your most obedient servant,

Gavin Low«. ,,

Islington^ , ^

Feb. 15, 1808.

E3

XVI. A

[ 70 ] •

XVL A Secf.jid Letter from E. V. on the Means of
gain'mg Power in Mechanics,

g^j^ To Mr, Tilloch,

IVlucH as the moderns are reckoned to surpass the antients
in nnathematical knowledge, and notwithstanding the ex-
perience and improvements in mechanics, during the later
and more enhirhtened an;es, it is a mortiFvin':i: truth that we
arc even at this day totally ignorant of the means formerly
employed, and very extensively in use, to move to vast di-
stances, and raise to great height, prodigious masses and
weights, such as the celebrated columns of Kgypt, Rome,
&c.^ and that with all our advantages over the antients, v^e
still remain unable to equal their practice in these respects.
It does not appear that our predecessors were gifted with su-
perior intellect or strength to the present race -, their means
inuit have been mechanical, and therefore must be within our
reach. — Why then should we not attempt and expect to do
as much as they did ? It is truly surprising that an art of
so useful and important a nature, so nearly allied to the me-
chanical powers in constant varied use and progressive im-
provement among us, has so long been lost and escaped
discovery ! Perhaps the time is not distant when this mighty
secret shall again be common for the general benefit of so-
ciety. My hunible endeavours have occasionally been di-
Y rected to this f^nc] ; and vyith this view I have contributed
any mite, and ^i;all continue so to do by the communica-
f\cjn, through your valuable Magazine, of relative experi-
me^its and results which may be novel, in the hope of sti-
mul^ing the exertions of the more scientific ; — for, as '' great
cv.ent'j oft owe their rise to trivial cause,'* my hints may
haply fi;rnish abler heads with ideas which may lead further
than I can pretend to penetrate j and thus, between us, the
period of success may be accelerated.

In my last, I gave account of an engine of my contri-
vance, which gained considerable power : — this engine has
since been so improved, that with the same moving power,
the same velocity, kc, it raises a weigjit of thirty pounds

instead

On the Use of Sulphur as a Fermifhge, 7i

infitead of twenty, and there is consequently reason to be*
lieve that it may yet be made far more powerful.

Aware of the reception which this extraordinary fact, so
contrary to estabhshed opinions, is Hkely to meet, I have
aoqght, and been so fortunate as to find, additional support,
in further experiments, and the construction of another
engine materially different from the first, which, however,
produces similar, and indeed greater effects.

More of this shall be the subject of my next paper ; and
in the mean time, those of your numerous readers, whp'
may think with me, that the means of gaining power cannot
be limited to the two which I have thus announced, have a
wide field opened for the exercise of their genius in this re-
search. I have the honour to be, sir,

Bracknell, y®"^ Very humble servant,

Feb. 23, 1808. E. Y.

XVII. On the Use of Sulphtr as a Vermifuge* By Joseph
Hume, Esq,, of Long- Acre y London*

To Mr. Tilloch.

AViNG been favoured with some additional information
respecting the efficacy of sulphur, and the proper way of
applying it to vegetables, I now fulfil the conditional pro-
mise I made in my last letter*. The method is truly sim-
ple ; for nothing more is required than to sprinkle sublimed
aulphur, or, as it is commonly called, flowers of brimstone,
over the leaves of the tree or plant, wherever the effects of
worms or insects prevail, or may be expected to come.
This may be sq easily accomplished, that it seems super-
fluous to point out any particular plan or apparatus. The
sulphur may be tied up in a piece of muslin or linen, and
with this the leaves and young shoots should be dusted ; or
it may be thrown on by means of a common swandown
puff, or even a dredging-box. However, if this practice
become general, no doubt some convenient instrument,

? Phil. Mag. vol. xxlx. p, 353.

E 4 . probably

7ft* Experiments for investigating

probably a pair of bellows, constructed on purpose, will be
contrived, so as to prevent unnecessary loss of the sulphur.

By the same friendly communication 1 have received fresh
assurances, not only of the powerful influence of sulphur as
a vermifuge against the whole tribe of worms and other in-
sects, which infest, and prey upon, vegetables ; but I also
find, that in other respects this substance is even congenial
to the health of those trees and plants on which it is sprin-
kled— that peach-trees in particular were remarkably im-
proved by the sulphur ; they absorbed it, and, it may be said,
Were even fond of it ; for it was evidently absorbed, and
must hive entered into the vegetable system. It was like-
wise noticed, that the verdure and other healthful appear-
ances were perceptibly increased ; for the quantity of new
shoots and leaves formed subsequently to the operation,
and having no sulphur on their surfaces, served as a kind of
comparative index, and pointed out distinctly the accumu-
lation of health.

Upon the whole, it may be observed, that, independently
of its deleterious effects on the vermin, the question respect-
ing these sanative powers of such an insoluble substance as
sulphur, seems to be one of the utmost importance ; and, I
should think, must be highly interesting to the physiologist,
and, indeed, to all men of science.
\ remain, sir,

your obliged and obedient servant,

Long-Acre, Jos. HuME,

Feb. 24, 1808.

XVIII. Experiments for investigating^ the Cause of the co-
loured conctntriQ Rings, discovered bij Sir Isaac Newton,
between two Object- glasses laid upon o,ne another. By
William Herschel, I^LD, F.R.S.*

J. jiE account given by Sir I. Newton, of the coloyred arcs
^cl rings which he discovered by laying two prisms or ob-

* From Philosophical Transactions fp.ir i807, Part 11.

ject-

the Cause of coloured concentric Rings, 73*

ject-glasses upon each other, is highly interesting. He very
justly remarks, that these phsenomena are " of difficult con-
sideration,," but that *' they may conduce to further disco-
veries for completing the theory of light, especially as to
the constitution of the parts of natural bodies on which
their colours or transparency depend*.'*

With regard to the explanation of the appearance of these
coloured rings, which is given by Sir I. Newton, I must
confess that it has never been satisfactory to me. He ac-
counts for the production of the rings, by ascribing to the
rays of light certain fits of easy reflection and easy trans-
mission alternat.ly returning and taking place with each ray
at certain stated intervals f. But this, without mentioning
particular objections, seems to be an hypothesis which can-
not be easily reconciled with the minuteness and extreme
velocity of the particles of which these rays^ according to
the Newtonian theory, are composed.

The great beauty of the coloured rings, and the pleasing
appearances arising from the different degrees of pressure of
the two surfaces of the glasses against each other when they
are formed, and especially the importance of the subject,
have often excited my desire of inquiring further into the
cause of such interesting phsenomena ; and with a view to
examine them properly I obtained, in the year 1792, the
two object-glasses of Huygens, in the possession of the
Royal Society, one of 122 the other of 1 70 feet focal length,
and began a series of experiments with them, which, though
many times interrupted by astronomical pursuits, has often
been taken up again^ and has lately been carried to a very
considerable extent. The conclusions that may be drawn
from them, though they may not perfectly account for all
the phaenomena of the rings, are yet sufficiently well sup-
ported, and of such a nature as to point out several modifi-
cations of light that have been totally overlooked, and others
that have never been properly discriminated. It will, there-
fore, be the aim of this paper to arrange and distinguish the
various modifications of . light in a clear and perspicuous

* Newton's Optics, i± ed.. p. 16D. f Ih'id. p. 956.

order.

7** Experiments for investigating

order, and afterwards to give my sentiments upon the cause
of the formation of the concentric rings. The avowed in*
tricacy of the subject *, however, requires, in the first place,
a minute detail of experiments, and afterwards a very gra-
dual development of the consequences to be deduced from
them.

As the word modification will frequently be used, it may
not be amiss to say, that when applied to light, it is intend-
ed to stand for a general expression of ail the changes that
are made in its colours, direction, or motion : thus, by the
modification of reflection, light is thrown back ; by that of
refraction, it is bent from its former course ; by the modi-
fication of dispersion, it is divided into colours, and so of
the rest.

I. Cff different Methods to make one Set of concentric Rings

visible.

In the beginning of my experiments I followed the New»
Ionian example, and having laid the two object-glasses of
Huygens upon one another I soon perceived the concentric
rings. It is almost needless to say that I found all the New-
tonian observations of these rings completely verified ; but
as his experiments seemed to be too much confined for draw-
ing general conclusions, I endeavoured to extend them ; and
by way of rendering the methods I point out very clear, I
have given one easy particular instance of each, with the
addition of a generalization of it, as follows :

First Method, On a table placed before a window I laid
down a slip of glass the sides of which were perfectly plain,
parallel, and highly polished. Upon this I laid a double
convex lens of 26 inches focal length, aiid found that this
arrangement gave me a set of beautiful concentric rings.

I viewed them with a double convex eye lens of Sj inches
focus mounted upon an adjustable stand, by which simple
apparatus I could examine them with great ease ; and as it
was not material to my present purpose by what obliquity
of incidence of light I saw the rings, I received the rays

♦ Newton'3 Optics, 4th ed, p. 288; endofObs. 12.

Irom

the Cause of coloured concentric Rings. 75

from the window most conveniently when they fell upon the
lens in an angle of a^bout 30 degree^ from the perpeadicu^
jar, the eye being placed on the opposite side at an equal
angle of elevation to receive the reflected rays.

Gmeralization. Instead of a plain slip of glass, the plain
side of a plano-concave, or piano-convex lens of any focal
length whatsoever may be used : and when the convex side
ofanylensis laid upon it, whatever may be the figure of
the other surface, whether plain, concave, .or convex, and
whatever may be its focal length, a set of concentric rincrs"
will always be obtained. I have seen rings with lenses of all
varieties of focus, from 1 70 feet down to one quarter of an
inch. Even a common watch-glass laid upon the same plain
surface will give them.

To ensure success, it is necessary that the glasses shoulxl
be perfectly well cleaned from any adhering dust or soil,
especially about the point of contact ; and in laying them
upon each other a little pressure should be used, accom-
panied at first with a little side motion, after which they
must be left at rest.

If the surface of the incumbent lens, especially when it is
of a very short focal length, is free from all imperfection
and highly polished, the adjustment of the focus of the
above-mentioned eye-glass, which 1 always use for vicwino;
the rings, is rather troublesome, in which case a small spot
of ink made upon the lens will serve as an object for a suf-r
ficient adjustment to find the rings. 'iviixvi,^

Second Method. Instead of the slip of glass, I laid down
a well poiished plain metalline mirror; and placing upon it
the same i;'6-inch double convex lens, I saw again a conj^
plete set of concentric rings.

It is singular that, in this case, the rings reflected from a
bright metalline surface will appear fainter than when the
same lens is laid on a surface of glass reflecting but littlo
light ; this may however be accounted for by the brilliancy
of the metalline ground on which these faint rings are seen,
the contrast of which will ofluscate their feeble appearance.

Generalization. On the same metalline surface every va-
riety of lenses may b« laid^ whatever be the figure of their

uppe

76 Experiments for investigating ^''■

upjjtr surface, whether plain, concave, or convex, and
whatever be their focal lengths, provided the lowest surface
renoains convex, and concentric rings will always be ob-
tained ; but for the reason mentioned in the preceding para-
graph, very small lenses should not be used till the experi-
mentalist has been familiarized with the method of seeing
these rings, after which lenses of two inches focus, and
gradually less, may be tried.

Third Method, Hitherto we have only used a plain sur-
face upon which many sorts of glasses have been placed ; in
order therefore to obtain a still greater variety, 1 laid down
a plano-convex lens of 15 inches focal length, and upon the
convex surface of it I placed the 26-inch double convex
lens, v/hich produced a complete set of rings.

Fourth Method. The same lens placed upon a convex
metalline mirror of about 15 inches focal length gave also a
complete set of rings. j

Generalization. These two cases admit of a much greater
variety than the first and second methods ; for here the in-
cumbent glass may have not only one, but both its surfaces
of any figure whatsoever ; whether plain, concave, or con-
vex ; provided the radius of concavity, when concave lenses
are laid upon the convex surface of glass or metal, is greater
than that of the convexity on which they are laid.

The figure of the lowest surface of the subjacent substance,
when it is glass, may also be plain, concave, or convex ; and
the curvature of its upper surface, as well as of the mirror,
may be such as to give ttiem any focal length, provided the
radius of their convexities is less than that of the concavity
of an incumbent lens; in all which cases complete sets of
concentric rings will be obtained.

Fifth Method. Into the concavity of a double concave
glass of 8 inches focal length I placed a 7-inch double con-
vex lens, and saw a very beautiful set of rings.

Sixth Method. Upon a 7-feet concave metalline mirror I
placed the double convex 26-inch lens, and had a very fine
set of rings.

Generalization, With these two last methods, whatever
may be the radius of the concavity of the subjacent surface,

provided

the Cause of coloured cmcentrlc 'Rings, 77

provided it be greater than that of the convexity of the in-
cumbent glass ; and whatever may be the figure of the upper
surface of the lenses that are placed upon the former, there
will be produced concentric rings. The figure of the lowest
surface of the subjacent glass may also be varied at pleasure,:
and still co;icentric rings will be obtained.

,^ II. Of seeing Rings ly Transmission,

The great variety of the different combinations of these
differently figured glasses and mirrors will still admit of fur-
ther addition, by using a different way of viewing the rings.
Hitherto^ the arrangement of the apparatus has been such as
to make them visible only by reflection, which is evident,
because all the experiments that have been pointed out may
be made by the light of a candle placed so that the angle of
incidence and of reflection towards the eye of the observer
may be equal. But Sir I. Newton has given us also an
observation where he saw these rings by transmission, i»
consequence of which I have again multiplied and varied the
method of producing them that way, as follows :

First Molkod, On a slip of plain glass highly polished on
both sides place the same double convex lens of 26 inches,
which had already been used when the rings were seen by
reflection. Take them both up together and hold thein
against the light of a window, in which position the con-
centric rings will be seen with great ease by transmitted
light. But as the use of an eye-glass will not be convenient
in this situation, it will be necessary to put on a pair oi
spectacles with glasses of 5, 6, or 7 inches focus, to mag-
nify the rings in order to see them more readily.

Second Method, It would be easy to_ construct an appara-
tus for viewing the rings by transmission fitted witii a pro-
per eye-glass ; but other methods of effecting the same pur-
pose are preferable. Thus, if the two glasses that are to
give the rings be laid upon a hollow stand, a candle placed
at a proper -angle and distance under them will show the
rings conveniently by transmitted light, while the observer
and the apparatus remain in the same situation as if they
were to be seen by reflection.

i Third

78- Experiments for investigating

Third Method. A still more eligible way is to use daylight
received upon a plain metalline mirror reflecting it upwards
to the glasses placed over it, as practised in the construction
of the common double microscope : but I forbear entering;
into a further detail of this last and most useful way of seeing
rings by transmission, as I shall soon have occr«iion to say
more on the same subject.

Gejieralization, Every combination of glasses that has
been explained in the first, third, and fifth methods of see-
ing rings by reflection will also give them by transmission,
when exposed to the light in any of the three ways that have
now been pointed out. When these are added to the former,
it will be allowed that we have an extensive variety of ar-
rangements for every desirable purpose of making experiments
upon rings, as far as sine;le sets of them are concerned.
III. Of Shadows,

When two or more sets of rings are to be seen, it will re-
quire some artificial means, not only to examine them cri-
tically, but even to perceive them ; and here the shadow of
some slender opaque body will be of eminent service. Ta
cast shadows of a proper sise and upon places where they are
wanted, a pointed penknife may be used as follows : .

When a plain slip of glass or convex lens is laid down,
and the point of a penknife is brought over either of them,
it will cast two shadows, one of which may be seen on the
first surface of the glass or lens, and the other on the lowest.

When two slips of glass are laid upon each other, or a
convex lens upon one slip, so that both are in contact, the
penknife will give three shadows; but if the convex lens
should be of a very short focus, or the slips of glass a little
separated, four of them may be perceived; fbr in that case
there will be one formed on the lowest surface of the incum-
bent glass or lens ; but in my distinction of shadows this
will not be noticed. Of the three shadows thus formed the
second will be darker than the first, but the third will be
taint. When a piece of looking-glass is substituted for the
lowest slip the third shadow will be the strongest.

Three slips of glass in contact, or two slips with a lent
upon ihcni, or also a looking-glass, a slip and a' lens put

together.

\

the Cause of coloured concentric Rings. 79

together, will give four shadows, one from each upper sur-
face and one from the bottom of the lowest of them.

In all these cases a metalline mirror may be laid under the
same arrangement without adding to the number of sha-
dows, its effect being only to render them more intense and
distinct.

The shadows may be distinguished by the following me-
thod : When the point of the penknife is made to touch the
surface of the uppermost glass or lens, it will touch the
point of its own shadow, which may thus at any time be
easily ascertained ; and this in all cases I call the first sha-
dow ; that which is next to it, the second ; after which
follows the third, and so on.

In receding from the point, the shadows will mix to-
gether, and thus become more intense ; but which, or how
many of them are united together, may always be known
by the points of the shadows.

When a shadow is to be thrown upon any required place,
hold the penknife nearly half an inch above the glasses, and
advance its edge foremost gradually towards the incident
light. The front should be held a little downwards to keep
the light from the underside of the penknife, and the sha*
dows to be used should be obtained from a narrow part of it.

With this preparatory information it will be easy to point
out the use that is to be made of the shadows when they
are wanted.

IV. Of two Sets of Rings,

I shall now proceed to describe a somewhat more com-
plicated way of observation, by which two complete sets of
concentric rings may be seen at once. The new or addi*
tional set will furnish us with an opportunity of examining
rings in situations where they have never been seen before,
which will be of eminent service for investigating the cause
of their origin, and with the assistance of the shadows to
be formed, as has been explained, we shall not find it diffi-
cult to see them in these situations.

First Method, Upon a well polished piece of good look-
ing-glass lay down a double convex lens of about 20 inches
focus. When the eye-glass has been adjusted as usual for

seemcf

80 Experiments for investigating

seeing one set of rings, make the shadow of the peilknife,
in the order which has been described, pass over the lens;
then, as it sometimes happens in this arrangement that no
rings are easily to be seen, the shado\^ will, in its passage
over the suiface, show where they are situated. When a
set of them is perceived, which is generally the primary one,
bring the third shadow of the penknife over it, in which
situation it will be seen to the greatest advantage.

Then, if at the same time a secondary set of rings has not
yet been discovered, it will certainly be perceived when the
second shadow of the penknife is brought upon the primary
set. As soon as it has been found out, the compound sha-
dow_, consisting of all the three shadows-united, may (hen
be thrown upon this secondary set, in order to view it at
leisure and in perfection. But this compound shadow should
be taken no further from the point than is necessary to cover
it ; nor should the third shadow touch the primary set. The
two sets are so near together, that many of the rings of one
set intersect some of the other.

When a sight of the secondary set has been once obtained,
it will be very easy to view it alternately with the primary
one by a slight motion of the penknife, so as to make the
third shadow of it go from one set to the other.

Besides the use of the shadows, there is another way to
make rings visible when they cannot be easily perceived,
which is to take hold of the lens .vith both hands, to press
it alternately a little more with one than with the other; a
tilting motion, given to the lens in this manner, will move
the two sets of rings from side to side ; and as it is well
known that a faint object in motion may be sooner perceiv-
ed than when it is at rest, both sets of rings will by these .
means be generally detected together.

It will also contribute much to facilitate the method of
seeing two sets of rings, if we receive the light in a more
oblique angle of incidence, such as 40, 50, or even 60 de-
grees. This will increase the distance between the centres
of the primary and secondary sets, and at the same time oc-
caaion a more copiou:* reflection of light.

instead of a common looking-glass a convex glass mirror

may

the Cause of coloured concentric Rings, SI

may be used, on which may be placed either a plain, a con-
cave, or a convex surface of any lens or glass, and two sets
of rings will be obtained.

In the same manner, by laying upon a concave glass mirror
a convex lens, we shall also have two sets of rings.

The generalizations that have been mentioned when one
get of rings was proposed to be obtained, may be easily ap<^
plied with proper regulations, according to the circumstances
of the case, not only to the method by glass mirrors already
mentioned, but likewise to all those that follow hereafter,
and need not be particularized for the future. In the choice
of the surfaces to be joined, we. have only to select such as
will form a central contact, the focal length of the lenses
and the figure of the upper surface being variable at pleasure.

Second Method. On a plain metalline mirror I laid a pa-
rallel slip of glass, and placed upon it the convex surface of
a 1 7-inch plano-convex lens, by which means two sets of
rings were produced.

Upon the same mirror the plain side of the plano-convex
glass may be laid instead of the plain slip, and any plain,
convex, or concave surface being placed upon the convexity
of the subjacent lens, will give two sets of rings.

The plain side of a plano-concave glass may also be placed
upon the same mirror, and into the concavity may be laid
any lens that will make a central contact with it, by which
arrangement two sets of rings will be obtained.

Third Method. Upon a small well polished slip of glass
place another slip of the same size, and upon them, lay a
39-inch double convex lens. This will produce two sets bf
rings ; bne of them reflected from the upper surface of the'
first slip of glass, and the other from that of the second.

Instead of the uppermost plain slip of glass we may place'
upon the lowest slip the plain side of a plano-oonvex
or plano-concave lens, and the same variety which has
been explained in the third method, by using any incum-
bent lens that will make a central contact, either with the
convexity or concavity of the subjacent glass, will always
produce two sets of rings.

Vol. 30, No. U7. Feb. 1808. F Fourth

^%, Experiments for investigating

Fourth Method. A more refined but rather more difficult
way of seeing two sets of rings, is to lay a plain slip of glass
on a piece of black paper, and when a convex lens is placed
upon the slip, there maybe perceived, but not without par-
ticular attention, not only th'e first set, which has already
been pointed out as reflected from the first surface of the slip,
but also a faint secondary set from the lowest surface of the
same slip of glass.

It will be less difficult to see two sets of rings by a reflec-
iion from both surfaces of the same glass, if we use, for in-
stance, a double concave of 8 inches focus with a double
convex of /j inches placed upon it. For, as it is well known
that glass will reflect more light from the furthest surface
when air rather than a denser medium is in contact with it,
the hollow space of the 8- inch concave will give a pretty
strong reflection of the secondary set.

Fifth Method. The use that is intended to be made of two
sets of rings requires that one of them should be dependent
upon the other : this is a circumstance that will be explained
hereafter; but the following instance, where two indepen-
dent sets of rings are given, will partly anticipate the subject.
When a double convex lens of 50 inches is- laid down with a
slip of s^lass placed upon it, and another double convex one
of 26 inches is then placed upon the slip, we get two sets of
rings of different sizes ; the large rings are from the 50-inch
glass, the small rings from the 26-inch one. They are to be
seen with great ease, because they are each of them primar}\
By tilting the incumbent lens or the slip of glass these two
sets of rino^s may be made to cross each other in any direc-
tion ; the small set may be laid upon the large one, or either
of them may be separately removed towards any part of the
glass. This will be sufficient to show that they have no con-
nection with each other. The phaenomena of the motions,
and of the various colours and sizes assumed by these rines,
when different pressures and tiltings of the glasses are used,
will afford some entertainment. With the assistance of the
shadow of the penknife the secondary set belonging to the
rings from the 26-inch lens will be added to the other two"

sets;

the Cause of coloured concentric Rings, 83

sets ; but in tilting the glasses this set will never leave its
primary one, while that from the 50-inch lens may be made
to go any where across the other two.

KV •'/; 'ii> ■:):;^f(fj •■\\

V. Of three Sets of Rings.

To see three sets of concentric rings at once is attended
with some difficulty ; but by the assistance of the methods
of tilting the glasses and making use of the multiplied sha-
dows of a penknife, we may see them very well, when there
is a sufficient illumination of bright daylight. ''

^^Wtrst Method. A 26-inch double convex lens placed upon
three slips of plain glass, will give three sets of rings. The
slips of glass should be nearly 2-tenths of an inch thick,
otherwise the different sets will not be sufficiently separated.
When all the glasses are in full contact, the first and second
sets may be seen with a little pressure and a small motion,
and, if circumstances are favourable, the third, which is the
faintest, will also appear. If it cannot be seen, some of the
compound shadows of the penknife must be thrown upon
it 5 for in this case there will be five shadows visible, several
of which will fall together and give different intensity to
their mixture.

Second Method. When a single slip of glass, with a 34-
inch lens upon it, is placed upon a piece of good looking-
glass, three sets of rings may be seen : the first and third
sets are pretty bright, and will be perceived by only pressing
the lens a little upon the slip of glass ; after which it will be
easy to find the second set with the assistance of the proper
shadow. In this case four shadows will be seen ; and when
the third shadow is upon the first set, the fourth will be over
the second set and render it visible.

Third Method. When two slips of glass are laid upon a,
plain metalline mirror, then a 26-inch lens placed upon the
slips will produce three sets of rings ; but it is not very easy
to perceive them. By a tilting motion the third set will ge-
nerally appear like a small white circle, which at a proper
distsfnce will follow the movement of the first set. Ais soon
as the first and third sets are in view, the third shadow of the
penknife may be brought over the first set, by which means

F 2 the

S4 Experiments for investigating

the fourtli shadow will come upon the second set, and in this
position of the apparatus it will become visible.

Fourth Method. On a plain ujetalline mirror lay one slip
of glass, but with a small piece of wood at one end under it,
so that it may be kept about one-tenth of an inch from the
mirror, and form an inclined plane. A i'6-inch lens laid
upon the slip of glass will give thrqe ?ets of rings. Two of
them will easily be seen ; and when the shadow of the pen-
knife is held between them, the third set will also be per-
ceived. There is but one shadow visible in this arrange-
ment, which is the third ; the first and second shadows being
lost in the bright reflection from the mirror.

Fifth Method. I placed a 6f-inch double convex upon an
8-inch double concave, and laid both together upon a plain
slip of glassw This arrangement gave three sets of rings.
They may be seen without the assistance of shadows, by
using only pressure and tilting. The first had a black and
the other two had white centres.

VI. Of four Sets of Rings.

The difficulty of seeing many sets of rings increases with
their number, yet by a proper attention to the directions that
are given, four sets of concentric rings may be seen.

First Method. Let a ^lip of glass, with a 26 -inch lens
laid upon it, be placed upon a piece of looking-glass. Under
one end of the slip, a small piece of wood one-tenth of an
inch thick must be put tokeep it from touching the looking-
glass. This arrangement will give us four sets of rings. The
first, third, and fourth may easily be seen, but the second set
will require some management. Of the three shadows which
this apparatus gives, the second and third must be brought
between the first and fourth sets of rings, in which situation
the second set of rings will become visible.

Second Method. When three slips of glass are laid upon
a metalline mirror, and a plano-convex lens of about 17
inches focus is placed with its convex side upon them, four
sets of rings may be seen ; but this experiment requires a
very bright day, and very clean, highly polished slips of
plain glass. Nor caa it be successful unless all the fore-
going

the Catcse of coloured concentric Rings. 65-

golng methods of seeing multiplied sets brings are become
familiar and easy.

I have seen occasionally, not only foiif SMlS^e, Ml.^ven
six sets of concentric rings, from a very simple arrarigemetii
of glasses : they arise from reiterated internal reflections j
but it will not be necessary to carry this account of seeing
midtiplied 'Sets of rings to a grfcater length. ^^■"^^'"^'

VII. Of the Size of the Rings. \

''^I'he diameter of the concentric rings depends lljioit the'ra-
dius of the curvature of the surfaces between which they are
formed. Curvatures of a short radius, cafteris paribus, give
smaller rings than those of a longer; hiit sit Isaac Newtoti
having already treated on this part of the subject at lafge,
it will not be necessary to enter further into it.
'*' I should however remark, that when two curving are con-
cerned, it is the application of them to each other that will
determine the size of the rings, so that large ones may be
produced from curvatures of a very short radius. A double
convex lens of 2^- inches focus, for instance, when it is laid
upon a double concave which is but little more in focal
length, gives rings that are larger than those from a lens of
t6 inches laid upon a plain slip of glass.

YUi, Of Contact. rt^J;/

The size of the rings is considerably affected by pressure.
They grow larger when the two surfaces that form them afe
pressed closer together, and diminish when the pressure is
gradually removed. The smallest ring of a set rpay be in-
creased by this means to double and treble its former dia-
meter: but as the common or natural pressure of glasses laid
upon any flat or curved surface is occasioned by their weight;
the variations of pressure will not'be vcrf consiclerable when
they are left to assume their own distance or cbntact. To
produce that situation, however, which' 'is 'geiifeiPally^ called
contact, it will always be "necessary to' giVe a liftle'motidh
backwards and forwards to the incumbent lens q'i' glass, ac-
companied with some moderate pTessiTr6,'^fter'Wh'icli it nr'aV
beieft-io settle prop^riy -by its -oXv^'w^r^hi:^ 'O- ; n v..a£.i?ifr

' F3 IX. Of

86 Experiments for investigating

IX. Of meastiring Rings.

It may be supposed from vvhai has. been said concerning
the kind of contact which is required for glasses to produce
rings, that an attempt to take absolute measures must be
liable to great inaccuracy. This was fully proved to me
when I wanted to ascertain, in the year 1 792, whether a lens
laid upon a metalline surface would give rings of an equal
diameter with those it gave when placed on glass. The
measures differed so much that I was at first deceived ; but
on proper consideration it appeared that the Huygenian ob-»
ject glass, of 122 feet focus, which I used for the experi"
ment, could not so easily be brought to the same contact on
metal as on glass ; nor can we ever be well assured that an
equal distance between the two surfaces in both cases has
been actually obtained. The colour of the central point, as
will be shown hereafter, may serve as a direction ; but even
that cannot be easily made equal in both cases. By taking
a sufficient number of measures of any given ring of a set,
when a glass of a sufficient focal length is used, we may
however determine its diameter to about the 25th or 30th
part of its dimension. nnjni^'

Relative measures for ascertaining the proportion of the
different rings in the same set to each other, may be more
accurately taken ; for in that case the contact with them all
will remain the same, if we do not disturb the glasses during
the time of measuring.

X. Of the Numler of Rings,

When there is a sufficient illumination, many concentric
rings in every set will be perceived ; in the primary set we
see generally 8. 9, or JO, very conveniently. By holding.the
eye in the most favourable situation I have often counted
near 2Q, and the pumber pf them is generally lost when they
grow too narrow and minute to be perceived, so that we can
never be said fairly to have counted them to their full extent.
In the second set I have seer^,,as,jmany as in the first, and
they are full as bright. The third set, when it is seen by a
metalline mirror under two slips, will be brighter than the

second.

the Cause of coloured concentric "Rings, 87

second, and almost as bright as the first: I have easily
counted 7, 8, and 9 rings.

XT. Of the Effect of Pressure on the Colour of the Rings,

When a double convex object glass of 14 or 15 feet focus
is laid on a plain ?lip of glass, the first colours that make
their faintest appearance will be red surrounded by green ;
the smallest pressure will turn the centre into green sur-
rounded by red : an additional pressure will give a red centre
again, and so on till there have been so many successive al-
terations as to give us six or seven times a red centre, after
which the greatest pressure will only produce a very large
black one surrounded by white.

When the rings are seen by transmission, the colours are
in the same manner subject to a gradual alternate change
occasioned by pressure ; but when that is carried to hs full
extent, the centre of the rings will be a large white spot sur-
rounded by black.

The succession and addition of the other prismatic colours
after the first or- second change, in both cases is extremely
beautiful; but as the experiment may be so easily made, a
description, which certainly would fall short of an actual
view of these phaenomena, will not be necessary.

When the rings are produced by curves of a very short
radius, and the incumbent lens is in full contact with the
slip of glass, they will be alternately black and white; but
by lessening the contact, I have seen, even with a double
convex lens of no more than two- tenths of an inch focus,
the centre of the rings white, red, grfcen, yellow, and black,
at pleasure. In this case 1 used an eye-glass of one inch
focus ; but as it requires much practice to manage such
small glasses, the experiment may be more coi^vcniently
made by placing a double convex lens of two-inch focus on
a plain slip of glass, and viewing the rings by an eye-glass of
S-J- inches ; then having first brought the lens into full con-
tact, the rings will be only black and white, but by gently
Jfting up or tilting the lens, the centre of the rings wilL as-
suipe various colours at pleasure.

F4 XII. Of

fi* Experiments for investigating

XII. Of diluting and concentrating the Colours.

Lifting up or tilting a lens being subject to great uncer-
tainty, a surer way of acting upon the colours of the rings
is by dilution and concentration. After having seen that
very small lenses give only black and white when in full
contact, we may gradually take others of a longer focus.
With a double convex lens of four inches the outward rings
will begin to assume a faint red colour. With 5, 6, and 7,
this appearance will increase ; and proceeding with lenses of
a larger focus, when we come to about 16, 18, or 20 inches,
green rings will gradually make their appearance.

This and other colours come on much sooner if the centre
of the lens is not kept in a black contact^ which in tjiese
experiments must be attended to.

A lens of 26 inches not only shows black, white, red, and
green rings, but the central black begins already to be di-
luted so as to incline to violet, indigo, or blue. With one
Qf 34, the white about the dark centre begins to be diluted,
and shows a kind of gray inclining to yellow. With 42 and
48, yellow rings begin to become visible. With 55 and 59,
blue rings show themselves very plainly. With a focal
length of 9 and i 1 feet, orange may be distinguished from
the yellow, and indigo from the blue. With 14 feet, some
violet becomes visible. When the 122 feet Huygenian glass
is laid on a plain slip, and well settled upon it, the central
colour is then sufficiently diluted to show that the dark spot,
which in small lenses, when concentrated, had the appear-
ance of black, is now drawn out into violet, indigo, and
blue, with little admixture of green ; and that the white ring;,
which used to be about the central spot, is turned partly
green with a surrounding yellow, orange, and red-coloured
space or ring ; by which means we ^eein to have a fair ana-
lysis of our former compound black and white centre.

One of my slips of glass, which is probably a little con-
cave, gave the rings still larger when the 122 feet glass was
firmly pressed against it. I used a liti)e side motion at th^
sanie time, and brought the glasses into such contact that
they adhered sufficiently to be lifted up together. With
this adhesion I perceived a colour surrounding a dark

centre

.^Vt':J^^tT^'|fo Cau^e of tolmired concenfnc i^/w^^r- ' ^^^'- S^

tcentre which T httvti iifever seen in any prismatic spectrum.
It is a kind of light brown, resembling the colour of a cer-
taifi'sort of Spanish snuff. The 170 feet object glass showed
the same colour also very clearly.

XIII. Of the Order of the Colours.

The arrangement of the colours in each compound ring or
alternation, seen by reflection, is, that the most refrangible
rays are nearest the centre ; and the same order takes place
when seen by transmission. We have already shown that
when a full dilution of the colours was obtained their arrange-
ment was violet, iridigo, blue, green, yellow, orange and red;
and the same order will hold good when the colours are
gradually concentrated again ; for though some of them
should vanish before others, those that remain will always
be found to agree with the same arrangement.

If the rings should chance to be red and green alternately,
a doubt might arise which of them is nearest the centre;
but by the method of. dilution, a little pressure, or some
small increase of the focal length of the incumbent lens,
there will be introduced an orange tint between them, which
will immediately ascertain the order of the colours.

In the second set of rings the same order is still preserved
as in the first j and the same arrangement takes place in the
third set as well as in the fourth. In all of them the most
refrangible rays produce the smallest rings.
XIV. Of the alternate Colour and Size of the Rings belong'
hig to the primary and dependent Sets,

When two sets of rings are seen at once, and the colour of
the centre of the primary set is black, that of the secondary
will be white; if the former is white, the latter will be black.
The same alternation will take place if the colour of the centre
of the primary set should be red or orange ; for then the
centre of the secondary one will be green ; or if the former
happens to be green, the latter will be red or orange. At the
same time there will be a similar alternation in the size of
ringy ; for the white rings in one set will be of the diameter
of the black in the other ; or the orange rings of the forniA
will be of equal magnitude with the green of the latter.

When three sets of rings are to be seen, the second and

third

00 Surgical Cases in the City and Finshury Dispensaries,
third sets will be alike in colour and size, but alternate in
both particulars with the primary set.

The same thing will happen when four sets are visible ;
for all the sets that are formed from the primary one will
resemble each other, but will be alternate in the colour and
dimensions of their rings with those of the primary set.

[To be continued.]

XIX. Report of SurgicQl Cases in the City and Finshury
Dispensaries for September 1807. J5y John Taunton, E^^.

JLn the month of September there were admitted on the
books of the City and Finshury Dispensaries 237 surgical
patients.

Cured or relieved - - 205
Died - - - - 4

Under cure - - - 28

237

.Since which time there have been admitted 963.
One of the fatal cases was that of Mrs. M. S. aet. 67^ who,
soon after the birth of her ninth and last child, was seized
with femoral hernia : the tumour was small, but painful,
attended with sickness and inclination to vomit; these
symptoms did not last long, as the hernia receded without
assistance : she had another attack in about six weeks,
which was also of short duration ; the hernia soon became
irreducible, and she had been exposed to similar attacks for
the last sixteen years of her life, for which time it had never
been completely returned : these were occasionally longer
and more severe ; the symptoms frequently continued for two
or three days, but were removed without any operation or
medicine, except some Daffy's elixir.

On the 22d of August she was seized with the usual
symptoms, viz. pain over the whole belly, particularly in
the region of the stomach, with a sensation of heat, vomit-
ing, cold sweats, intermitting pulse, and suppression of
stools for four days : the tumour was now much larger than
before, being nearly the size of a child's head at birth : at
..|his period she had a motion of a small quantity of feculent

matter.

Royal Society, 91

matter, after which the bowels were confined for ihr^ days,
when she was taken with diarrhoea, an acute pain in the
bowels, cold sweats, pulse variable, vomiting of feculent
matter ; but the hiccup was not very distressing : — these
symptoms continued for nine da\'S, being sixteen from the
attack, when she sunk under the disease.

The medicines given during this illness were, opium,
calomel, extract, colocynth. cum calomel, enema communis,
and the enema cum nicotiana. She could not be prevailed
on to submit to the operation.

On dissection, the intestines were distended with flatus,
the colon was much enlarged and inflamed, part of the syg-
moid flexion was contained in the hernial sac, but not the
whole circumference of the intestine, which left thecdnal per-
vious. The adhesions were firm around the mouth of the sac,
from which the intestine could not be separajled, and the coats
were much thickened'by inflammation which approached to
gangrene. The omentum was much inflamed and adhered to
the hernial sac ; and that part of the omentum within the
sac was much enlarged and more firm, which, together
with the adhesions, had rendered this an irreducible hernia,

John Taunton,

Surgeon to the City and Finsbury
Grevllle-street, Hatton-garden, Dispensaries, Lecturer on Ana«

February 23, 1808. • tomy, Surgery, Physiology, &c.

XX. Proceedings of Learned Societies ,

ROYAX SOCIETV.

On the 5th of February, a letter from Mr. Knight, to the
president, was read, on the inconvertibility of the bark of
trees into the alburnum. The author, as usual, detailed
the effects of a great many experiments made to confirm
this opinion, which he announced in the conclusion of a
letter read before the Society last season, (see Philosophical
Magazine, No. 109, vol. xxviii. p. 43.) One of the most
obvious reasons assigned for the truth of this opinion was,
that many trees having barks very dissimilar, have wood
very similar; and that, had the alburnum been formed «f the
bark, the wood must consequently have been as different as
2 the

92 Roijal Society,

the l^ark was. On the other hand, many trees with bark
very shnilar, have wood very different. These facts, in con-
junction with some minute expcTiments, Mr. Knight con-
cluded as decisive that the hark is not transmuted, as MaU
pighi supposed, into alburnum ; but that each performs its
peculiar function in the ceconomy of vegetation.

February 11 and 18. Several mathematical papers on
the properties of a circle, Slc , were presented to the Society
fcy the astronomer royal, but were not of a nature to be
read. A curious paper on cranites^ or the idiotism of the
inhabitants of alpine regions, who are affected with goitres,
or swellings about the head, was read. From the author's
researches among the people of Switzerland, and his inves-
tigation of the supposed connection between this species of
mental imbecility and. goitres, (which are generally ascribed
la the effect of using snow-wa,ter on the glands,) he was led
to conclude that cranites exists frequently where there are no
goitres, and that many families suffer the latter complaint
without experiencing the former.

February 25. A. Marsden, esq-., in the chair. A ge-
ological paper on the whin-dykes in the north of Ireland,
in a letter to Mr. Davy, was laid before the Society.

A continuation of Mr. Home's experiments on the func-
tions of the spleen was read, in which this able naturalist
operated on asses with extract and tincture of rhubarb, as
related in his former experiments on dogs. The spleen and
the colon were found impregnated with the rhubarb, when
none was found in the liver. Several curious experiments
were made to ascertain the quantity of serum and of rhubarb
found in the blood in the vena cava, the left auricle of the
heart, and other members : but the results are not satis^
factorily established. /orjin-'M;

A letter from Mr. Mutdoch, to the president, was read,
containing an account of the origin, progress, and present
irtate of gas-lights. It appears that so long ago as 1739
Dr. Clayton, in the Philosophical Transactions, discovered
the inflammability of gas procured from coals : but this
knowledge was never adapted to practice till about sixteen
years ago, when the author, at a foundry in Cornwall, first
•\^\ proposed

New Process for preparing Calomel, 9t

proposed the application of this gas-light to ceconomical pur-
poses, and actually carried it into eftcct. In 1798 he also
cstahlished it on a larger scale at Messrs. Bolton and Watts,
Soho, Birniingham. But at Messrs. Phillips and Go's
cotton factory it has been carried to the highest degree of
perfection, and on the most extensive scale, of any place \i\
the kingdom. From a statement of the relative expense
of candles and gas, it appears that for the light which that
manufactory required, 2000/. a year would be expended
in candles; whereas ihe wear and tear and expenses oF gas-
lights do not much exceed 600/. a year, amounting to about
one-third the expense of candles. . 1

IMPERIAL ACADEMY OF SCIENCES AT ST. PETERSBURGlti^-

'^This Academy has published the 13th volume of their
Memoirs, It coii tains, among other interesting articles, a
description of the celebrated silver mine of Zuseoff, ou
Mount Athol, in Siberia, with an account of the total pro-
duce of that mine from 1747 to 1793 inclusive.

UNIVERSITY OF WILNA. ,j

This body has announced the following as the subject of
a prize question : ^< What are the chief diseases of plants,
and what analpgy exists between them and those of ani-i
malsr"

The prize is 100 ducats; and the memoirs, written in
Latin, French, or Polish, must be sent before the first of
September 1808 to the rector of the University, under
cover to Messrs. IJeiser or Karner, bankers in Wilna. The
prize will be adjudged in the month of January J8O9.

" .-.; : ■ :-v' -r ' ',T. .f•:^f•^W):,-^.^^-^■^rt ""^^

XX r. Intelligence and Miscellaneozis Articles.

NEW PROCESS tOT^ PREPARING CALOMEL.

xjLn important improvement in the preparation of that es-
sential article of the pharmacopoeia, calomel, has been re-
cently introduced by Messrs. Luke Howard and company,
chemists. It consists in a peculiar mode of conducting the
final suliimation by fire; by which the vapour of the calo-
mel.

94 MisccUdneous,

mel, instead of being suffered to concrete, as usual, into a
folid cake at the upper part of the vessel, is thrown out into
water, where it is instantlv condensed into a white powder
possessing the impalpable fineness of a precipitate. The
imperfect operations of grinding and levigating are thus su-
perseded, and the defects which have so generally been
complained of in the medicine from this cause remedied.
The product is lighter than levigated calomel, in conse-
quence of its greater comminution, three parts by weight
occupying the same space a.s Jive of the latter.

M. Douett Richardott, a French agriculturist, has long
practised with success a new method of curing cattle
whose stomachs are swoln from having fed upon wet forage.
It consists in administering to the animal the twentieth part
of a pound of gunpowder, mixed in a pint of milk, when
first seized with the colic from eating grass or clover
highly charged with dew. This remedy was long agO' an-
nounced in the French Journals, but M. Richardott has
been the first to publish the results of its application.

M. Allaire, a French chemist, has published a new me-
thod of scouring wool, which consists in dipping it repeat^
edly in a ley of quick-lime. The chalky earth forms an
animal soap with the grease. By this means the wool is
speedily and oeconomically scoured, and without altering
its qualify.

LIST OF PATENTS FOR NEW INVENTIONS.

To Willis Earle, of Liverpool, in the county of Lancaster,
merchant, for his invention of certain improvements in the
tillage and dressing of land, and the cultivation of plants. —
January 13, 1808.

To James Lee, of Plaistow, in the county of Essex,^
merchant, and John Perrin, oF the same place, esq., for
their new invented method of preparing certain kinds of
hemp ; by which the value and the utility of the articles are
much increased. January 13.

To John Wilkinson, of Bradley Iron Works, in the
liberty of Bilston, in the county of Stafford, esq., for his

new^

List of Patents for New Inventions, 03

new invented method of making pig or cast metal from the
ore; which, when manufactured into bar iron, will be
found equal in quality to any that is. jjp ported from Russia
or Sweden. January 23.

To Andrew Johansen, of Hommerlon, in the parish of
Hackney, in the county of Middlesex, gent., for certain
improved methods of manufacturing a kind of tablet or ar-
tificial whetstone, for whetting or sharpening razors, pen-
knives, surgeons* instruments, and other cutlery, and which
he usually denominates ^* Cotific Tablets." January 23.

To Edward Moore Noble, of Birmingham, in the county
of Warwick, surgeon, for his new method of making of
carbonate of lead, commonly called white lead. Jan. 23.

To Samuel Phelps, of Cuper's Bridge, Lambeth, in the
county of Surry, esq., for his improvements in manufac-
turing soap. January 23.

To Thomas Preston the younger, of Tooley-street^ South-
wark, in the county of Surrey, lead merchant, for his im-
proved method of setting boilers for steam engines, pans for
melting lead, tin, pewter, and other metals of easy fusion ;
and a new method of discharging the pans for melting lead,
tin, pewter, &c., as before named, when full, and setting
coppers and boilers of every description. January 26.

To George Savage, of Huddersfield, in the county of
York, watch-maker, for his improved method of regulating
or equalizing the force or power of the main-spring in
watches, or other machines for measuring time. Jan. 26.

To William Stewart, of Limehouse, in the county of
Middlesex, builder, for certain improvements in making
bricks and tiles. January 26.

To Joseph Johnson and John Wilmot, of Birmingham,
in the county of Warwick, manufacturers, for their new
invented warming-pans, which are not only applicable to the
purpose of airing and warming beds, but also for airing and
warming rooms or carriages, or for other purposes requiring
a long and protracted heat. January 28.

To William Newberry, of St. John-street, in the county
of Middlesex, gent., for his improved machinery for the
purpose of sawing wood^ splitting or paring skins. Jan. 30.

METEORO-

96

Meteorology,

meteoro^^ogical table,

By Mr. Cakev, op the Strand,

For February 1808.

Thermometer.

Mi

.

^

Days of the
JVIonth. ,

;z.

8 c

1 Height of

the Baiom.

Inches. "

(U >. c

OS: Xa >^

Weather-

•

Jan. 27

26^^

37"

41^'

29-30

6

Cloudy

28

46

46

34

•25

11

Fair

29

34

42

42

•62

30

Fair

30

46

49

48

•70

17

Showery

31

49

52

49

•70

14

Cloudy

Feb. 1

48

53

48

•71

13

Cloudy

■ 2

43

50

40

'55

30

Stormy

3

38

42

3b

•90

18

Fair

4

32

41

36

30-30

16

Fair

5

41

47

37

•10

10

Fair

6

42

50

47

29-78

12

Stormy

7

48

49

44

•89

30

Cloudy

8

33

39

34

•73

0

Rain

9

32

39

32

•82

25

Cloudy

10

28

35

30

30-03

21

Fair

U

29

40

38

29-75

16

Cloudy

12

28

29

25

•50

0

Great fall of
snow

13

28

30

25

•80

8

Fair

14

24

30

24

30-01

15

Fair

15

19

33

33

29-98

0

Snow

16

34

42

34

•88

4

Cloudv

17

32

39

40

30-02

11

Cloudy

18

42

43

38

•03

0

Rain

' 19

33

41

32

•28

21

Fair

20

30

38

30

•45

16

Fair

21

29

37

31

•50

20

Fair

22

30

39

32

•46

18

Fair

23

32

38

35

•37

10

Cloudy

24

35

37

33

'57

15

Cloudy

N. B. The Barometer's height Is taken at one o'clock.

[ 97 ]

XXir. On Blasting Rocks, and Tamping. By John"
Taylor, Esq,

To Mi\ TillocL

SIR,

A LETTER from an engineer of celebrity to Mr. Nicholson,
and published in the ninth volume of his Journal, introduced
to the public some time ago an account of the use of sand
in blasting rocks or other hard substances : a letter from
another gentleman, published in your Magazine soon after,
continued the subject, and mentioned other modes of con-
fining the gunpowder employed for this purpose ; and we
have been lately informed of the result of experiments made
in France upon what Mr. Nicholson calls Mr. Jessop*s me^
thod of blasting rocks with sand, by a notice published in
the Philosophical Journal of July last.

As the process has long been known, however, in this
neighbourhood, and the constant experience of the work-
men in the mines and quarries agrees pretty nearly with the
French report, it may not be useless to detail the instances
in which it may be advantageously employed, and to point
out the cases where it is not likely to be effectual ; and in
mines the latter are more numerous than the Ibrmrr.

As another substance has been lately introduced into use
here, which possesses advantages occasionally overall others,
it will likewise give me pleasure to fnake it more generally
;icnown, especially as this is an operation on the easy execu-
tion of which often depends the safety of the lives of
the persons conducting it. The new process I allude to, is
that of closing the hole, upon the proper charge of gunpow-
der, with clay wrought to rather a soft consistency, and
rammed- in in suOicient quantity, which, where the resis-
tance is not too great, possesses the following advantage^.
It may be applied to holes bored in all directions ; may be
perforated for the fuse w iilmul danger,' and is^peculiarly adapt-
ed for rock in which gunpowder is liable to be rapidly in-
jured by water. Sand can only be used where the rock is
bored perpendicularly or nearly so ; and in mines but few
holes of this description occur> the effect of a given <^uan-

Vol. 30. No, 118. March 1808, G ti^r

yS On Blasting Rocksy and Tamping,

lity of gunjjovvder being certainly greater in those holes the
mouths of which are lower than the end which contains the
charge. This fact has frequently been shown by a charge
in a detached piece of rock confintd by tamping, as the
miners call it, in the usual way, and fired with the mouth
of the liolti upwards. A certain quantity of tamping will
in this position be blown out, and the rock remain entire.
tf ihe same hole be recharged with the same quantity of
powder, and tamped so as to present an equal resistance,
the rock will be torn to pieces by merely altering its posi-
timi, so that the charge may lie higher than the mouth of
the hole. Thus it may be inferred, that in firing artillery
there is more danger of bursting guns when they are laid with
their muzzles depressed, than when pointed at any degree
of elevation.

Holes for blasting in mines are so frequently very wet as
to preclude the use of sand where other circuni stances
would favour it; for though, by violently compressing tough
clay into the fissures, the portion of the hole that is to con-
tain the gunpovvder may be made dry, yet to render it so
throughout its whole length would be aprocess considerably
too tedious. Here the advantage of applying clay for tamp-
ing is very great. The hole is instantly filled up with a
water-tight substance, and an opening for the fuse is made
through it with an iron rod, by a pressure so gentle as to
hazard no explosion in the performance.

Clay is likewise more likely to be used by miners than
sand, if they are acquainted generally with its effect, from
its being always at hand, it being so necessary to the other
operations of boring and charging holes that it is always in
use where blasting is 2:oing on ; and the difficulty of intro-
ducing any substance that requires the least exertion to pro-
cure or manage among workmen is well known, whatever
safctv crease it may afford them.

The French engineers pretty accuTately describe the cases
in whi<?h'sand will fail in its effect; that is^ eitiier wbenj,!tb;e
hole is bored to a small depth, so that the quantity of gun-
powder required to break the rock occupies such a length
of 4t ^ not to afford s^-acg for a sulBcient coluiBWoif sand^
^> .■•.•^.i)i<i .an ,< or

On Blasting Rocks, and Tamping* Oi)

or where, from the density of the rock, or its being confined
as in the shafts and levels of mines by the numerous points
of contact, very great force is required to produce its frac^
ture.

i ani inclined to believe that though in thefet ca^eS both
sand and clay niiist yield to the usual mode of tamping,
yet that clay will commonly produce the fracture where
fand will fail to do so. About t4en years ago an experi-
ment was made in Cornwall upon a loose rock on the sur-
face, and sand was blown out without any effect having
been produced: an equal quantity of gunpowder, confined
by a small quantity of tamping, broke the rock ; which
proved that the resistance was far inferior to that of the com-
mon mode. And from many late trials made with clay, in
holes tnoderately deep, in Wheal Friendship copper min6'
and the tunnel of the Tavistock canal, I have found clay to
answer nearly a« well as tamping; though certainly in what
the workmen call shallow holes, and in vfery hard rock,
neither that nor sand can be depended upon. In quarries
and open works where deep holes can and always ought to
be had, where the groutid is for the most part dry, and the
rock is seldom very hard, both will be found eminently
iiscfiil, and will contribute much to the safety of the work-
men. '

Mr. Farey m;;ntions, in his letter in your Macrazine, his
having seen coal -ashes employed as tanipipg. The fact is,
that mo»t friable substances are proper for this purpose,
those being the best" that combine with friability a cer-
tain degree of tenacity : the miners esteem soft yellow copper
Ore, or the common galena, in the highest degree, and next
perhaps is broken tile; but what is commonly used is the soft
6chis)tus rock which is attendant on most metallic veins.

These substance^ are beaten into the hole upon the charge
of gunpowder, while a small taper iron rod called the nail,
kept in during the process, forms, on being withdrawn, the
vent for the rush tilled with gunpowder, which constitutes
the fuse. It is by the occasional attrition of this iron nail
against siliceous particles, either in the act of ramming^
striking it out, that dreadful accidents sometimes occur.

G2 The

100 On Blasting Roch, and Tamping,

The use of copper nails vvouki prevent this ; but though
often tried, tlie miners, from their being not quite so con-
venient, will not continue the use ofthem.

The plan of adding to the resistance of tamping by load-
ing the aperture of the hole, as proposed by M. Gillet
Laumont, is in continual use among the Cornish miners,
but in a more simple and cflfectual way than he suggests ;
and it is certain that some rock could not be blasted without
this assistance.

M. Pictet, it is said in the same article of the Philo-
sophical Journal for July, has conceived that a more
effective explosion for the purposes of mining might be
obtained by leaving a partial vacuity, or by the chamber
not being completely filled by the gunpowder. Now this
idea is directly in opposition to the received opinion of per-
sons conversant with these operations; but not having made
any accurate experiments on the subject, I shall only state a
case that appears to be in point. We are frequently obliged
in very wet ground to use gunpowder in cartridges of thin
tinned plate ; and as these cannot be made to fill up the
diameter of the chamber completely, we obtain, what he
conceives is desirable, a less concentrated exj)losion; but so
far is it from being beneficial, rliat every miner will use
every other means before he employs gunpo*Vder in this way,
because it is universally found to require a much greater
quantity for a given effect, and much more, I conceive, than
can be attributed to the small degree of resistance offered by
the material of which the cariridge is 'oruK d.

The most promising scheme for facilitating the operation
of blasting rock that I have heard of, has been suggested
very lately to me by a friend whose mechanical skill and
injrenuitv are well known, and who has lately applied with
surprising dexterity that powerful agent gunpowder at great
depths under water.

A sort of powder is made of double or treble the
strength of common cannon powder, and if this be applied
to the uses of mining, he thinks that holes of half the usual
capacity might contain sufficient charges in equal lengths.
If so, it is certain that such holes, being considerably less in

diametcir

On the Muriatic Ether. » 101

diameter than those now made, might be bored with much
more ease and rapidity ; and those only who know the labou]*
and tediousness of the operation, besides ihe great expense
of tools in hard siliceous rocks, can justly appreciate the
value of such an improvement. I have not yet been fur^-
nished with the means of making any trial of this plan, but
1 hope before long to have it in my power.

1 have troubled you at some length on this subject ; but
as it is one with which is connected the safety of several
thousand men in this kingdom alone, and when it is con-
sidered, as I have heard from good authority, that the annual
expense of gunpowder for the mines in Cornwall and Devon
amounts to more than 30,000/., it becomes an object worthy
discussion, if means therefrom should arise of lessening the
risk to the workmen or of cost to the mines, particularly
in the present distressing state to which they are reduced
from the very low price at which the metals are now sold.
I am, sir, your most obedient servant,

John Taylor, Engineer.

Holwell House, Devon,
Dec. 1, 1807.

XXrit. 'Itxtfact of a Memoir vpon ihe Murinfic Ether, as
read at the French Instiiidey 17 ih of Fehiiary, 1S07.
%M. 7i«kNARD*.

-After havins; examined why the muriatic ether has hi-
therto remained almost unknown among chemists, although
frequently the object of chemical experiments, the author
^ives the method of obtaining it. For this purpose, as the
above ether is habitually in the state of gas, tHe following
apparatus must be employed ;

We put in a retort barely capable of containing the mix-
ture, an equal part in volume of highly concentrated nuiriatic
acid and alcohol at 36''; we shake thtm welj, in order to
bring all their molecules in contact. . This beinc; done, we
throw into the retort seven or eight grains of sand, in order
t.o avoid the boiling up, which, without this precaution,

* Antif df Clauir, lom. Ixi. p. 'J90.

t? 3 miu;ht

109 On the Muriatic Eiher,

might take place in the course of the operation ; \vc thet\
place it in the naked fire upon a conmion furnace, by means
of a grating of iron wire, and adopt Welter's tube lo it,
which enters into a flask with three necks, double in
capacity to the retort eiTi ployed, and half filled with water
at the temperattrre of 20 or 25"*, so that the tube penetrates^
a considerable way into the water: afterwards vve introduce
into the second neek a straight tube of safety ; and iiito
the third we introduce a crooked one, which is fixed into
an earthen vessel under flasks full of water, at the same de-
gree of heat as the former, and supported by a knob screwed
iht6 the middle of it. Wheti the apparatus is thus arranged,
thl; retort must be gradually heated; and in kbout 2a or 25
niinutes we see hubbies arise from the lower part of the liquid^
ind particularly from the Surface of the grains of '^atid.
Thesebubbles soon increase, and abundance of etherised gas
is obtained; acid, alcohol, and water, pass over at the same
time, but they reihain in the firfet flask. From 500 gram-
mes of air artd an equal volume of alcohol, we may obtair^
twenty litres and upwards of etherized gas perfectly pure.
But we shall extract much more from it, if, when the extri-
catioii of the gas begins to slacken, we add a fresh quantity to
the residue, namely, the strongly acid liquor which ronains in
the retort, and the volume of >vhich is thcrinearjy equivalent
to two fifths of the liquor from which it comes-. M. The-
nard even thinks, that if, by means of a straight tube going
to the bottom of the retort and of a proper length, we could
pour from time to time warm alcohol into the latter, the ethe-
rized gas would be formed in still greater abundance ; for wc
should conceive that there is every moment more alcohoj
volatilized than muriatic acid, and that we should thus re*
establish between these two bodies the primitive proportions,,
which are more proper than anv other for the success of the
operation. In all cases the njanagenient of tlic fire is of the
greatest importance : if it be too weak, no etherized gas is
produced j if too strong, but very little is produced. Be-
sides, we do not etherize the alcohol sensibly by chargimr
it with muriatic acid gas, nor do we obtain ether more scn-

* The centigrade thermometer is the one intended. — Edit.

sibly

On the Muriatic Ether, 103

sibly by bringing together the acid and the alcohol in va^
pours into a tube about the temperature of about SO*'. It is
therefore by preserving a just medium in the application of
the fire that we succeed completely. All this proceeds from
too small or too great an elasticity in the alcohol, and the
muriatic acid prevents their reaction upon each other.
One precaution we must also take, is to use the same water
for collecting the gas, and to employ the least quantity P9S7
sible, because itdissolves it in a remarkable degree.

This gas is absolutely colourless ; the smell of. it is strongly'
etherized, and the taste sensibly saccharine. It has no kind
of action either upon turnsole tincture, syrup of violets, or
lime-water. lis specific gravity compaKcd to that of air is
2*219 to -f is" of the centigrade thermometer, and; at
O™ 75 of pressure at the same temperature, and at the same
pressure water dissolves its own volume of it. At this same
ilegrce of pressure also, but at + 11° of teinperature, the
etherized gas becomes liquid. We may procure a great
quantity of it in this state, by using an apparatus similar to
that we b^ve just described ; simply, in place of fixing the
last tube under a flask full of water, we must plunge it to
the bottom of a lopg, straight, well dried probe, and sur-
rounded with ice, which we must renew in proportior]^.a$ it
melts. It is in this probe that the etherized gas alone
arrives and is entirely liquefied ; for, when once the vessels
co«itain no more air, we niay wiihout the least danger spp-
press its communicaiion with the atmosphere. ..;?,

Wlibn thus Tujucfied, this ether is of acjemarkable limpi-
dity, as in the state of gas it is without colour and with-
out action upon turnsole tincture and syrup of violets; as
well as the etherized gas, it is very soluble in alcohol^
from which we may in a great measure pep^rate it by water-;
like this gas, it has also a very decided smell, and a very
distinct taste, wliich has something analogous to that of
sugar, and which is particularly remarkable in vv'ater which
is saturated with it, which may perhaps be employed sug*
cessfully in medicine. When poured upon the hand, it
suddenly evaporates and produces a considerable cold, leav-
jng a small whitish residue. At -f- 5" of temperature (cenii-

Cj 4 grade

101 On the Muriatic El her,

grade thermometer) it weighs 874, water weighing 1000.
Thus, aUhough it is far more volatile than the jtulphuric
ether, and, a fortiori, than alcohol, not only is it thicker than
the fornier, but even than the latter oF these two bodies.
Lastly, it does not congeal at a temperature of — 29^ (cen-
tigrade thermometer).

Hitherto we have seen nothing in this ether which does
not perfectly agree with that presented by other matters ; it
is nothing else than a substance curious from its nor
velty, and particularly from the facility with which it is
gasitied and liquefied. When wc reflect upon it a little
more, it appears one of the most singular and extraordinary
compounds we can produce. It does not in the least red-
den turnsole tincture ; the strongest alkalis have no action
upon it ; the solution of silver does not meddle with it at
all ; and all this, whether we employ it in the gaseous or
liquid state, or dissolved in water : if we set fire to it, there
is suddenly developed such a quantity of muriatic acid, that
this acid precipitates in a mass the concentrated nitrate of
silver, suffocates those who respire it, and even appears in
the form of vapours in the surrounding air.

Is the muriatic acid formed in this inflammation, as. we
are induced to think, or is it only set at liberty? This is
the question which the author of the memoir afterwards en-
deavours to resolve.

If the muriatic acid be formed in the combustion of the
etherized gas, the radical of this acid must exist in the gas;
3nd this radical necessarily comes froqi the alcohol, or from
the muriatic acid decomposed by the alcohol, or, what is not
very probable,' although not impossible, from both. In the
iirst case, by distilling a mixture of alcohol and muriatic
acid, we ought to find after the distillation all the muriatic
acid employed, besides that which appeared in the com-
})UStion of the gas formed ; in the second case, on the cout
trary, a greal quantity of acid ought to disappear in this di-*
^tillatiim ; but by keeping an account of that which is de-
veloped in the combustion of the gas formed, this quantity
of acid precisely, ^nd no more, ought to reappear entirely.
Ju the t:hird ca^q^, ffom this distillation a loss of acid shou'd

*ilSQ

On the Muriatic Ether. lOi

also result ; but this loss should be more than compensated
by the quantity of acid which the combustion of the ga«
formed ought to produce. Now, on performing this distil-
lation upon 450'937 grammes of muriatic acid of a specific
gravity of 11-349, at 5° temperature (centigrade thermo-
meter), and upon a volume of highly rectified alcohol equal
to that of the acid, there are formed 23 litres of etherized
gas al the, temperature of 21° of the ccntio;rade tiijermome-
tcr, and at the pressure of 0"" 745, and there disappear
122*288 grammes of acid.

The first hypothesis is consequently false, since it is de-
monstrated that, even should the radical of the muriatic acid
exist in the etherized gas, this radical would proceed not
merely from the alcohol, but rather either from the muriatic
acid alone, or from the muriatic acid and alcohol.

" Let us inquire if it proceeds from the muriatic acid alone,
as supposed in the second hypothesis : but here there are
two ways of considering the phcenomenon : either the mu-
riatic acid must have been decomposed by the alcohol, so
that its radical, without its other principle, is to be found in
the etherized gas; or this decomposition will have been
such, that all the principles of the muriatic acid will be found
in the etherized gas, not united, and not forming muriatic
acid, but combined with the principles of the alcohol, and
in the same stale in which hydrogen, oxygen, carbon, and
azot exist in animal or vegetable matters. Now if the radi-
cal of the muriatic acid exists alone in the other principle,
or without a portion of the other principle of the muriatic
acid ii; the etherized gas, we ought, by decomposing this
gas in a red-hot tube, and deprived of the contact of the air,
to obtain no acid at all, or else less of it than has disap-
peared in the experiment which produced it : and if this gas
contains not only the radical of the muriatic acid, but also
all the constituent princij)les of that acid ; as those princi-
ples, whatever they are, have a strong tendency to combine,
we should conceive that by destroying the etherized ga^ » y
fire, without the contact of the air, we shall probably ob-
tain the whole quantity of muriatic acid v\hich has disap--
pcared m the c:<pcrin)cut by which we procured it. Jt was

thertfwr^

106 On the Muriatic Ether,

therefore of the greatest importance to produce this decom-
position in close vessels. The operation was performed on
900 grammes of concentrated muriatic acid, and upon an
equal volume of well rectified alcohol. Between the red-hot
glass tube, in which the gas was decomposed, and the retort
in which it was produced, there was a large tubulated flask
containing water at about 15^ or 16°, in order to catch the acid,
the alcohol and the water, which might be volatilized along
with this gas ; the glass tube, besides, communicated, with
two otlier flasks, one containing potash and the other water,
irj order to absorb all the acid, which might re-appear in the
operation : finally, the gases were collected by means of
another lube. To ensure the success of the operation, the
glasatv^beifihould be well luted, and the iirc also well ma-
naged to prevent the tube from melting. Although in this
experiment there oucfht to have been produced nearly 5Q
]itrcs>iOf etherized' gaa, and nearly 250 grammes of acid
ought lohave disappeared in the first place, yet all the acid
except four grammes rc-ap))eared in the red-hot tube, and
carbc to; be dissolved in the two flasks of the apparatus.
Thus, of all the suppositions hitherto formed of the mu-
riatic acid being a compound body, one only is admissible,
which infers that the elements of the muriatic acid exist in
the etherized gas combined with the elements of the alco-
hol, in the same manner as the elements of water, carbonic
acid, ammonia, Sec, exist in vegetable and animal sub-
stances.

Now if we suppose the muriatic acid to be a simple body,
we must then necessarily regard etherized gas as formed of
nmriatic acid and alcohol, or of a body con ing from the
decomposition of alcohol; for alcohol is perhaps decon)-
posed v.'hen we distil it with the muriatic acid. In all
cases, the question is thus brought to a choice of the two
hypotheses. Let us now try their merits as well as we can.

One, namely that which we have last mentioned, prcr
S'Mts us with phienomena of difl^cult explanatio:i. In fact,
it must be supposed that alcohol, or the body w Inch re-
presents it, acts upon the muriatic acid with much more
energy than the strongest alkali, since tl^is alkali cannot

take

On the Muriatic Ether. 1 07

take it off from it, and since, as will ^be subiequently de-
jnonstratcd^ the muriate of potash contains less acid than
the etherized gas ; and how can we cc-sccive, on the other
hand, that the nitrate of silver, which takes up all the mu-
riatic acid from the muriate of potash, cannot take it dp from
the etherized gaS;, which contains more than the muriate of
potash does ?

In the other hypothesis, on the contrary, every thing if
i^aturally explained. We see the reason why the etherized
gas does ncit redden turnsole tincture, and the alkalis do not
alter it; why the nitrate of silver produces no precipitate
from it; and why, on taking fire, so large a quantity of mu-
riatic acid is produced, that it appears in the air. in the forn^
of vapours: — in short, we can reconcile every thing with
the phaenomona of other bodies, .nqioiz-jq j:)^! «*Jib ^s =• . .

M. Thenard, however, is far from admtttthg t-he^ one
and rejecting the other in a decided manner. Both deserve to
be investigated ; and whatever happens, the results must be
very important, \.i-*.-

Not^ Upon the DJscovenj of the Muriatio Ether. .

V^iiE'k t'rek^ tlife foregoing memoir' t(1*tWe Ytl'stftute, the
"whole of the members, among vvliOmAvei'e'' Messrs. Bcr-
^Jbollet, 'Chaptal, Devoux, Fourcroy, Guj^toh, Vauquelin,
Gay-Lussac", he, regarded the results it contained as
being cxtremclv novel, and Wlt<e siritck with the Conse-
quences which might be drawn from it. M. Proust, who
was then in Paris, and before whoin I repeated the experi-
ment of testing the etherized gas by the tinctur6 of turn-
sole and ihe nitrate of silver, before and after the combustion
of the gas, &c., evinced the same surprise with the French
chemists. A few days afterwards, however, M. Gay-Lussac,
ou perusing the , German Journal of Gehlen, accidentally
discovered in a. note that Gehlen himself had made experi-
ments upon the muriatic ether, and published them in his
Joij'rnal for 1804. M. Gay-Lussac did me the favour to

♦ A/w. de Cliimicy torn. hi. p. fsOS.

translate

106 Oil the. Muriatic Ether.

translate M. Gchlen's memoir ; and as it has a great siiiii^
larity to mine, I shall give the following extract :
■ M. Gehlen made muriatic ether with the smoking muriate
of tin and alcohol, by employing an equal part in weight of
boih. ^Hc also made it in Basse's method (a chemist of Ha-
meln), by a mixture of sea-salt, concentrated sulphuric acid
and alcohol, from which it was never thought that any
thing else than sulphuric ether could be extracted. He ob-
tained none with thciTiurialic acid alone. In short, M. GelY-
Icn recognibcd most of the properties which I did in the
muriatic ether. Thus he saw that this ether is ntost fre-
quently in the state of gas, that it liquefies at about + 10° of
Reaumur, that it is slightly soluble in water, that it has a
saccharine taste, that it does not redden turnsole tincture,
that it does not precipitate the nitrate of silver, and that
when wc burn it a great quantity of muriatic acid is de-
veloped. M. Gehlen made no experiment, however, to prove
from whence this muriatic acid came, or to ascertain the
quantity produced by the etherized gas ; neither did he
attempt to establish the theory of this etherification. It is
in this . respect only that my labours differ from his. We
differ a little also, but not remarkably, as to the process I
employed for making the muriatic ether, and by rpeans of
which I obtained in an instant probably more ether than by
any other, and an ether purer also than M. Gehlen's, since
his weighed 845 only, and mine 874, a greater specific
gravity in the present instance being a proof of greater

Having no doubt, from the above, that tne muriatic
ether had been made in Gerniany, and that its property of
producing muriatic acid when burning w^s also known ;
and convinced as I was on the other hand, that. in France
and Spain the fact was unknown, I endeavoured to ascer-
tain if the English chemists knew any thing of the matter.
For this purpose I applied to M. RiffJuilt, the superintendant
of the gunpowder manufactories, and who was at that mo-
ment translating the third edition of Thomson's System of
Chemistry, a work full of erudition, and begun long after

M. Geh!en*s

Memoirs of Efasmus Darwin^ M, D. 1 0§

M. Gehlen's memoir appeared. M. Riffault read to me
every thing respecting the muriatic ether, but I found no-
thing about Gehlen, or the singular properties he relates of
the muriatic ether. Mr. Thomson only speaks oF the pro-
cess of Basse, which consists in mixing melted sea-salt,
alcohol^ and sulphuric acid ; and which > with the exception
of the fusion of the salt, has been pointed out by several
chemists. I think myself therefore entitled to conclude,
that in Great Britain, as well as in France and Spain, the
muriatic ether was unknown, and that, being ignorant of
M. Gehlen's labours, I have at least the merit of publishing
it. How often does it happen that a discovery is made in
one country, which had been known in another long before!
and this happens because all learned men do not speak one
language, and their works are not always translated. This
is the case with M. Gehlen's discovery*.

XXIV. Memoirs cf the late Erasmus Dakwin, M.D.

[Continued from vul. xxix. p. 339.]
. DARWINIANA.

In Doctor Darwin's First Class, Ord. I. Gen. 1, irientioning
arterial .hre?norrhage, he suggests the breathing an air wiih
less of oxygen. In the hcemopioe of arterial bluod,^ he pro-
poses, besides the reduced air, making the patient sick by
whirling round in a chair suspended by a rope j- actual vo-
niitinir, a practice we believe (irst introduced by the I'amous
Dr. Willis ; bathing in cold \vat<T, or sudden inunersionof
some of the limbs, or sprinkling the whole body with cold
water. For the hcemoptoe narium, bleeding of the uo^e, he
advises plunging the head into cold water with powdered
salt hastily dissolved in it: lint strewed with wheat 'flour

* Since wrkinjT tHe above, M. Boullay, a respcctal.'c apotliecarv' in Paris,
Informed me thnt he made the ether in que>tiou with the muria'tic acid and
iilcohoi long ago, a-thouj^h he never gave publicity to hi? ex{>€rin3eia'S,
because he d d not think they were so complete as they ought to have been.
I am proud to have an opportunity of doing justice to M. Boullay.

Note by M. TarNARu.
-•^^ ^ put

no Membhs of Erasinus Darwin, M. D,

put up the nostrils ; or a solution of steel iu brandy ap*
plied to the vessel by means of lint.

Arriving at Gen. ^', mentioning sudor calidus, warni
sweat, he has the following curious observations on the
use of calico and flannel :

*' If an excess of perspiration is induced by warm or stimu-
lant clothing, as by wearing flannel in contact with the skin
in the summer months, a perpetual febricula is excited,
both by the preventing the access of cool air to the skin,
and by perpetually goading it by the numerous and hard
points of the ends of the wool ; which, when applied to the
tender skins of vounp:; children, frequently produce the red
gum, as ii is called ; and in grown people, either an erysipelas,
or a miliary eruption, attended with fever.

^' Shirts made of cotton or calico stimulate the skin too
much by the points of the fibres, though less than flannel ;
whence cotton handkerchiefs make the noV-e sore by fre-^
quent use. The fibres of cotton are, I suppose, ten times
shorter than those of flax, and the number of points in con-
sequence twenty times the number; and though the manu-
facturers singe tlicir calicoes on a red-hot iron cylinder, yet
I have more than onec seen an erysipelas induced or increas-
ed by the stimulus of calico, as well as of flannel.
■ " The increase of perspiration by heat, either of clothes of
of fire, contributes much to emaciate the body; as is welf
known to jockeys, who, when they are a stone or two too
heavy for riding, find the quickest way to lessen their weight
is by sweating themselves between blankets in a warm room ;
but this likewise is a practice by no means to be recom-
mended, as it weakens the system by the excess of so gene-
ral a stim.ulus, brings on a premature old age, and shortens
the span of life ; as may be further deduced from the
quick maturity and shortness of the lives of the inhabi-
tants of Hindostan and other tropical climates.

" M. Buff on made a curious experiment to show this cir-
cumstance. He took a numerous brood of the butterflies oi
silkworms, some hundreds of which left their eggs on the
same day and hour ; these he divided itito two pareels ; and
placing one pared in the soutfi window, and the other in
- the

Memoirs of Erasmus Darmitf M, D, ill

the north window of his house, he observed, that those iu
the colder situation hved many (hiys longer than those in
the warmer one. From these observations it appears, that
the wearing of flannel clothing next the skin, whi<:h is now
so much in fashion, however useful it may be in the winter
to those who have cold extremities, bad digestions, or ha-
bitual coughs, must greatly debilitate them, if worn in the
warm months, producing fevers, eruptions, and premature
old age."

He makes the following ingenious and unfortunately too
true observations respecting the diarrhoea infantum, gripes
in infants :

" Milk is found curdled in the stomachs of all animals, old
as well as young, and even ot carnivorous ones, as of havvkft
(Spallanzani). And it is the gastric juice of the calf which
is employed to curdle milk in the process of making cheese.
Milk is the natural food for children, and must curdle in
their stomachs previous to digestion ; and as this curdling
of the milk destroys a part of the acid juices of the stomach,
there is no reasfon for discontinuing the use of it, though it
is occasionally ejected in a curdled stale. A child of a
week old, which had been taken from the breast of its dying
mother, and had by some uncommon error been suffered to
take no food but water gruel, became sick and griped iu
twenty-four hours, and was convulsed on the second day,
at)d died on the third ! When all young quadrupeds, as
well as children, have this natural food of n)ilk prepared
for them, the analogy is so strong in favour of its salubrity,
that a person should have powerful testinxjny indeed of its
disagreeing, before he advises the discontinuance of the use
of it to young children in health, and much more so iu
svckness. The farmers lose many of iheir calves, which arc
brought up by grud, or gruel and old milk ; and among
the poor children of Derby, who are thus fed, hundreds are
Carved Into the scrophula, and either perish, or live in a
state of wretched debility.

*' When young children are brought up without a breast,
they should for the first two months have no food but new
Hiilk 3 since the addition of any kind of bread or floiar is

liable

i\it ^lemoirs of Erasmus Darwin, AT, D,

liable W ferment, and produce too much acidity , as appears
by the consequent diarrhoea with green dejections and gripes ;
the colour is owing to a mixture of acid with the natural
quantity of bile, alid the pain to its stimuhis. And they
should never be fed as they He upon their backs, as in that
posture they are Necessitated to swallow all that is put into
Hieir mouths ; but when they are fed as they are sitting
up, or raised up, when they have had enough they can
permit the rest to run out of their tnouths. This circum-
stance is of great importance to the health of those children
who arc reared by the spoon, since, if too much food is given
them, indigestion, and gripes, and diarrhoea, are the conse-
quence; and if too liftlc, they become emaciated ; and of
this exact quantity their own palates judge the best."

His observations are no less curious rcs^tcUn^ perspirath
fcetida, fetid perspiration :

''^ The uses of the perspirable matter are to keep the skin
soft and pliant, for the purposes of its easier flexibility du-
ring the activity of our limbs in locomotion, and for the
preservation of the accuracy of the sense of touch, which is
difluscd under the whole surface of it to guard us against the
injuries of external bodies ; in the same manner as the se-
cretion of tears is designed to preserve the cornea of the eye
tnoist, and in consequence transparent : yet has this cu-
taneous mucus bet II believed by many to be an excrement ;
and I know not h(nv many fanciful theories have been built
Qu its supposed obstruction. Such as the origin of catanh^,
coughs, inflanmiations, erysipelas, and herpes.

" To all these if may be sufficient to answer, that the an-
tient Grccian&r oiled themselves all over ; that some nations
have painted themselves all over, as the Picts of this island ;
that the Hottentots smear themselves all over with grease.
And lastly, that many of our own heads at this day are co-
vered with the fi(7ur of wheat and the fat of hogs, according
to the tyranny of a filthy and wasteful fashion, and all this
wiihout inconvenience. To this must be added the strict
analogy between the use of the pcr3j)irable matter and the
mucous fluids, which are poured for similar purposes upon
>all the internal memhrancii of the body; and besides its
3 being

Memoirs of Erasmus Darwin, M. D. - 113

'feeing In its natural state inodorous ; which is not so with
the other excretions of faeces, or of urine.

^' In some constitutions the perspirable matter of the lungs
acquires a disagreeable odour ; in others the axilla, and in
others the feet, emit disgustful effluvia ; like the secretions
of those glands, which have been called odoriferae ; as those
which contain thccastor in the beaver, and those within
the rectum of dogs, the mucus of which has been supposed
to guard them against the great costiveness which they are
liable to in hot summers ; and which has been thought to
occasion canine madness; but which, like their white ex-
crement, is more probably owing to the deficient secretion
of bile. Whether these odoriferous particles attend the
perspirable matter in consequence of the increased action of
the capillary glands, and can properly be called excremen-
titious ; that is, whether any thing is eliminated, which
could be hurtful if retained ; or whether they may only con-
tain some of the essential oil of the animal ; like the smell
which adheres to one's hand on stroking the hides of some
dogs ; or like the effluvia, which is left upon the ground,
from the feet of men and other creatures ; and is perceptible
by the nicer organs of the dogs, which hunt them, may
admit of doubt.

*^ M. M. Wash the parts twice a day with soap and water ;
with lime water; cover the feet with oiled silk socks, which
must be washed night and morning. Cover them with
charcoal recently made red-hot, and beaten into fine pow-
der and sifted, as soon as cold, and kept well corked in a
bottle, to be washed off and renewed twice a day. Inter-
nally rhubarb grains vi. or viii. every night, so as to procure
a stool or two extraordinary every day, and thus by in-
creasing one evacuation to decrease another.*'

He gives a cure for the tape-worm*

^' The tape-worm is cured by an amalgama of tin and
quicksilver, such as is used on the back of looking-glasses ;
an ounce should be taken every two hours, till a pound is
taken; and then a brisk cathartic, of Glauber's salt two
ounces, and common salts one ounce, dissolved in two
wine-pints of water, half a pint to be taken every hour till

Vol. 30. No, 118. March 1808. H it

11 4 Memoirs of Erasmus Darwin^ M. D»

it purges. The worm extends from the stomach to the anuJ^
and the amalgama tears it from the intestine by mechanical
pressure, acting upon it the whole way. Electric shocks
through the duodenum greatly assist the operation. Large
doses of tin in powder. Iron filings in large doses. The
powder of fern- root seems to be of no use, as recommended
by M. Noufflier.*'

He makes the following judicious observations on the
cure of the ascarides, or thread- worm :

^^Ascarides are said to be weakened by twenty grains of
cinnabar and five of rhubarb taken every night, but not to
be cured by this process. As these worms are found only
in the rectum, variety of clysters have been recommended.
I was informed of a case, where solutions of mercurial oint-
ment were used as a clyster every night for a month without
success. Clysters of Harrowgate water are recommended^
either of the natural, or of the factitious, as described be-
low, which might have a greater proportion of liver of
sulphur in it. As the cold air soon destroys them, after
they are voided, could clysters of iced water be used with
advantage ? or of spirit of wine and water ? or of ether and
water ? Might not a piece of candle, about an inch long,,
or two such pieces, smeared with mercurial ointment, and
introduced into the anus at night, or twice a day, be effec-
tual by compressing their nidus, as well as by the poison of
the mcircury ?

'' The clysters should be large in quantity, that they may
pass high in the rectum, as two drams of tobacco boiled a
minute in a pint of water. Or, perhaps, what might be still
more efficacious and less inconvenient, the smoke of to-
bacco injected by a proper apparatus every night, or alter-
nate nights, for six or eight weeks. This was long since
recommended, I think, by Mr. Turner of Liverpool • and the
reason it has not succeeded, I believe to have been owing to
the imperfections of the joints of the common apparatus for
injecting the smoke of tobacco, so that it did not pass into
the intestine, though it was supposed to do so, as I once
observed. The smoke should be received from the appa-
ratus into a large bladder ; and it may then be certainly in-
jected

Experiments for investigating , &c, 1 1 5

jetfed like the common clyster with sufficient force; ot^'ef-
wise oiled leathers should he nicely put round the joints of
the machine, and a wet cloth round the injecting pipe, to
prevent the return of the smoke by the sides of it. Clysters
of carbonated hydrogen gas, or of other factitious airs,
might be triced. ' ''

'' Harrowgate water takert into the stonlach, so as to indiifc^
six or seven stools every morning, for four or six weeks, \ji
perhaps the most efficacious method in common use. A
factitious Harrowgate water may be m^lde probably of greater
efficacy than the natural, by dissolving one ounce of marine
«alt, (called bay salt,) and half an ounce of magnesia Glau-
ber's salt, (called Epsom salt, or bitter purging salt,) in
twenty-eight ounces of water. A quarter or half a pint of
this is to be taken every hour or two hours in the morning,
till it operates, with a tea-spoonful of a solution of liver of
sulphur, which is to be made by putting an ounce of hepar
sulphuris into ha! fa pint of water." '

[To be continued.]

XXV. ExperimeJits for investigalmcf the Cause of the co-
loured concentric Rings y discovered by Sir Isaac Newton,
hetiveen two Object-glasses laid upon one another. By
William Herschel, LLD. F.R.S,

■ ' ' [Continued from p. 90.]

XV. Of the sudden Change of the Size and Colour of the
Mings in different Sets.

Wme^ two sets of rings are viewed vrhich are' dependent
upon each other, .th<^ colour of their centres and of all the
rings in each set, may be made to undergo a sudden change
by the approach of the shadow of the point of a penknife or
other opake slender body. To view this phsenomenon pro-
perly, let a 16-inch double convex lens be laid upon a piece
of looking-glass, and when the contact between them has
been made to give the primary set with a black centre, thiat
of the secondary will be white." To keep the lens in this

H 2 contact.

116 £xperime?itsjbr investigating

contact, a pretty heavy plate of lead with a circular hole in
it of nearly the diameter of the lens should be laid upon it.
The margin of the hole must be tapering, that no obstruc-
tion may be made to either the incident or reflected light.
When this is properly arranged, bring the third shadow of
the penknife upon the primary set, which is that towards
the light. The real colours of this and the secondary set
will then be seen to the greatest advantage. When the
third shadow is advanced till it covers the second set, the
second shadow will at the same time fall upon the first
set, and the colour of the centres, and of all the rings in
both sets, will undergo a sudden transformation from black
to white and white to black. *

The alternation of the colour is accompanied with a
change of size, for as the white rings before the change were
of a different diameter from the black ones, these latter,
having now assumed a black coloqr, will be of a different
size from the former black ones.

When the weight is taken from the lens the black con-
tact will be changed into some other. In the present ex-
periment it happened that the primary set got an orange-
coloured centre, and the secondary a green one. The same
way of proceeding with the direction of the shadow being
then pursued, the orange centre was instantly changed to a
green one, while at the same moment the green centre was
turned into orange. With a different contact I have had the
primary set with a blue centre and the secondary with a deep
yellow one; and by bringing the second and third shadows
alternately over the primary set, the blue centre was changed
to a yellow, and the yellow centre to a blue one ; and all
the rings of both sets had their share in the transformation
of colour and size.

If there are three sets of rings, and the primary set has a
black centre, the other two will have a white one ; and
when the lowest shadow is made to fall on the third set, the
central colour of all the three sets will be suddenly changed,
the first from black to white, the other two from white to
black.

A full explanation of these changes, which at first sight
1 have

the Cause of coloured concentric Rings, 1 1 7

have the appearance of a magical delusion^ will be found in
a future article.

XVI. Of the Course of the Raj/s hj which different Sets of
, Rijigs are seen.

In order to determine the course of the rays, which giv-e
the rings both by reflection and by transmission, we should
begin from the place whence the light proceeds that forms
them. In figure I, (PI. VI.) we have a plano-convex lens laid
upon three slips of glass, under which a metalline mirror is
placed. An incident ray, 1,2, is transmitted through the
first and second surface of the lens, and comes to the point
of contact at 3. Here the rings are formed, and are both
reflected and transmitted : they are reflected from the upper
surface of the first slip, and pass from 3 to the eye at 4 : they
are also transmitted through the first slip of glass from 3
to 5 ,• and at 5 they are again both reflected and transmitted ;
reflected from 5 to 6. and transmitted from 5 to 7 ; from 7
they are reflected to 8, and transmitted to 9 ; and lastly
they are reflected from 9 to 10. And thus four complete
sets of rings will beseen at 4, 6, 8, and 10.

The most convenient way of viewing the same rings by
transmission, is that which has been mentioned in the se-
cond article of this paper, when light is conveyed upwards
by reflection. In figure 2, consisting of the same ar^range-
ment of glasses as before, the light by which the rings are to
be seen comes either from 1, 2, or 3, or from all these places
together, and being reflected at 4, 5, and 6, rises up by
transmission to the point of contact at 7,' where the rings
are formed. Here they are both transmitted up to the eye
at 8, and reflected down to 9 ; from 9 they are reflected up
to 10, and transmitted down to 11; from 11 they are re-
flected to 12, and transmitted to 13; and lastly, from 13 they
are reflected to 14 ; so that again four. sets of rings will be
seen at 8, 10, 12, and 14.

This being a theoretical v/ay of conceiving how the rays
of light may produce the effects, it will be required to show
by experiments that this is the actual progress of the rays,

H 3 and

^^f Experiments /or investigating

and that all the sets of rings we perceive are really reflected
or transmitted in the manner that has been pointed out ;
but as we have so many reflections and transmissions before
us, it will be necessary to confine these expressions to one
particular signification when they are applied to a set of
rings.

When the centre of the rings is seen at the point of con-
tact, it is a primary set ; and I call it reflected, when the
rays which come to that point and form the rings undergo
an immediate reflection. But I call it transmitted, when
the rays after having formed the rings about the point of
contact are immediately transmitted.

Th\is in figure 3 and 4 the rays a h c, d ef, give reflected
sets of rings j and the rays g h i, k I m, in figure 3 and 6,
give transmitted sets.

In this denomination, no account is taken of the course
of the rays before they come to a, d,. g, k ; nor of what be-
comes of them after their arrival at c, f, i, m : they may
either come to those places or go from them by one or more
transmissions or reflections, as the case may require j .but our
donomination will relate only to their course immediately
after the formation of the rings between the glasses.

The secondary and other dependent sets will also be called
reflected or transmitted by the same definition ; and as a set
of these rings formed originally by reflection may come to
the eye by one or more subsequent transmissions ; or being
formed by transmission, may at last be seen by a reflection
from some interposed surface, these subsequent transmis-
sions or reflections are to be regarded only as convenient
ways to get a good sight of them.

With this definition in view, and with the assistance of a
principle which has already been proved by experiments, we
may explain sonie very intricate phaenomena; and the satis-
factory manner of accounting for them will establish the
truth of the theory relating to the course of rays that has
been described.

The principle to which I refer is, that when the pressure
is such ^s to give a blapk centre to a set of rings seen by

reflection^

ihe Cause of coloured concentric Rings, 1 1 9

reflection, the centre of the same set, with the same pres-
sure of the ji^lasses, seen by transmission, will be white *.

I have only mentioned black and white; but any other
alternate colours, which the rings or centres of the two sets;
may assume, are included in the same predicament.

XVI I. Why two <^n?iected Sets of Rings are of alternate

Colours,

It has already been shown, when two sets of rings arc
seen, that their colours are alternate, and that the approach
of the shadow of a penknife will cause a sudden change of
them to take place. I shall now prove that this is a very
obvious consequence of the course of rays that has been
proposed. Let figure 7 and 8 represent the arrangement
given in a preceding article, where a 1 6-inch lens was laid
upon a looking-glass, and gav€ two sets of rings with cen-
tres of different colours : but let figure 7 give them by one
set of rays, and figure 8 by another. Then, if the incident
rays come in the direction which is represented in figure 7,
it is evident that we see the primary set with \U centre at 2
by reflection, and the secondary one at 4 by transmission.
Henc€ it follows, in consequence of the admitted principle,
that if the contact is such as to give us the primary set with
a black centre, the secondary set must have a white one ;
and thus the reason of the alternation is explained.

But if the rays come as represented in figure 8, we see
the primary set by transmission, and the secondary one by
reflection ; therefore, with an equal pressure of the glasses,
the primary centre must now be white, and the secondary
one black.

Without being well acquainted with this double course of
rays, we shall be liable to frequent mistakes in our estima-
tion of the colour of the centres of two sets of rings ; for by
a certain position of the light, or of the eye, we may see one
set by one light and the other set by the other.

XVIir. Of the Cause of the sudden Change of the Colours,

Having thus accounted for the alternation of the central

• See Article XI. of this Paper.

H 4 colours.

120 lExperiments for investigating

colours, we may easily conceive that the interposition of the

penknife must have an instantaneous effect upon them.

When it stops the rays of figure 7, which will happen when

its second shadow falls upon the primary set, the rings will

then be seen by the rays 1, 2, 3, 4, and 1, 2, 3, 3, 6, of

figure 8. When it stops the rays of figure 8, which must

happen when the third shadow falls upon the primary set,

we then see both sets by the rays 1, 2, 3, and 1, 2, 4, 3, qf

figure 7. When the penknife is quite removed both sets of

rays will come to the point of contact, and in some respects

interfere with each other ; but the strongest of the two,

which is generally the direct light of figure 7, will prevail.

This affords a complete explanation of all the observed phge-

nomena : by the rays of figure 7 the centres will be black

and white ; by those of figure 8 they will be white and black ;

jmd by both we shall not see the first set so well as when the

third shadow being upon it has taken away the rays of

figure 8 : indeed we can hardly see the secondary set at all,

till the shadow of the penknife has covered either the rays

of figure 7 or of figure 8. ,,,

As soon as we are a little practised in the managemeht of
the rays, by knowing their course, we may change the co-
lour so gradually as to have half the centre white while the
other half shall still remain black ; and the same may be
done with green and orange, or blue and yellow centres.
The rings of both sets will also participate in the gradual
change ; and thus what has been said of the course of rays
in the l6th article will again be confirmed.

XIX. Of the Place where the different Sets of Rings are to

le seen.
By an application of the same course of the rays, we may
now also 'determine the situation of the place where the dif-
ferent sets of rings are seen : for according to what has been
said in the foregoing article, the situation of the primary set
should be between the lens and the surface of the looking-
glass : and the place of the secondary one at the metalline
coaling of the lowest surface. To try whether this be ac-
tually as represented, let us substitute a metalline mirror

with

the Cause of coloured concentric Rings, 121

with a s-lip of glass laid upon it in the room of the piece of
looking-glass ; and let there be interposed a short bit of
wood, one-tenth of an inch thick, between the slip of glass
and the mirror, so as to keep up that end of the slip which is
towards the light. . This arrangement is represented in fi-
gure 9, where both sets of rays are delineated. Then if we
interpose a narrow tapering strip of card, discoloured with
japan ink, between the slip of glass and the mirror, so as to
cover it at 7, we do not only still perceive the primary set,
but see it better than before : which proves that, being situ*-
ated above the slip of glass, the card below cannot cover it.
If on the contrary we insert the strip of card far enough,
that it may at the same time cover the mirror both at 4 and
at 7, we shall lose the secondary set; which proves that its
aituation was on the face of the mirror.

When several sets of rings are to be perceived by the same
eye-glass, and they are placed at different distances, a par^
ticular adjustment of it will be required for each set, in order
to see it well defined. This will be very sensible when we
attempt to see three or four sets, each of them situated
lower than the preceding ; for without a previous adjust-
ment to the distance of the set intended to be viewed we
shall be seldom successful : and this is therefore a corrobo-
rating proof of the situation that has been assigned to differ-*
pit sets of rings.

XX. Of the Connection between different Sets of Rings ^
It will now be easy to explain in what manner different
gets of rings are connected, and why they have been called
primary and dependent. When the incident rays come to
the point of contact and form a set of rings, I call it a pri-
mary one : whenT tl\is is formed some of the same rays are
continued by transmission or reflection, but modified so as
to convey an image of the primary set with opposite colours
forward through any number of successive transmissions or
reflections : whenever this image comes to the eye, a set
of rings will again be seen, which is a dependent one,
Many proofs of the dependency of second^ third, and fourth

sets

122 Exper'wientsfor investigating

sets af rings upon their primary one may be given ; — I shaU
onlv mention a few.

When two sets of rings are seen by a lens placed upon a
looking-glass, the centre of the secondary set will always
remain in the same plane with the incident and reflected
rays passing through the centre of the primary one. If the
point of contact, by tilting is changed, the secondary set
will follow the motion of the primary set ; and if the look-
ing-glass is turned about, the secondary will be made to
describe a ciroie upon that part of the looking-glass which
surrounds the primary one as a centre. If there is a defect
in the centre or in the rings of the primary set, there will be
exactly the same defect in the secondary one ; and if the
rays that cause the primary set are eclipsed, both sets will
be lost together. If the colour of the primary one is changed,
that of the secondary will also undergo its alternate change,
and the same thing will hold good of all the dependent rings
when three or four sets of them are seen that have the same
primary one.

The dependency of all the sets on their primary one may
also be perceived when we change the obliquity of the inci-
dent light ; for the centres of the rings will recede from one
another when that is increased and draw together when we
lessen it, which may go so far that by an incidence nearly
perpendicular we shall bring the dependent sets of rings
almost under the primary one.

XXI. To account for the Appearance of several Sets of Rings
with the same coloured Centres,

It has often happened that the colour of the centres of
different sets was not what the theory of the alternation of
the central colours would have induced me to expect ; I have
seen two, three, and even four sets of rings, all of which
had a white centre. We are however now sufticiently pre-
pared to account for every appearance relating to the colour
of rings and their centres.

Let an arrangement of glasses be as in figure 9. When
this is laid down so as to receive an illumination of day^

li^ht.

the Cause of coloured concentric Rings. 123

light, which should not be strong, nor should it be very
oblique, the reflection from the mirror will thfen exceed that
from the surface of glass ; therefore the primary set will be
seen by the rays 6, 7, coming to the mirror at 7, and going
through the point of contact in the direction 7, 2, 3 ; which
proves it to be a set that is seen by transmission, and it will
therefore have a white centre. The rays 1 , 2, 4, passing
through the point of contact, will also form a transmitteci
set with a white centre, which will be seen when the reflec-
tion from 4 to 5 conveys it to the eye. But these two sets
have no connection with each other; and as primary sets
are independent of all other sets, I have only to prove that
this secondary set belongs not to the primary one which is
seen, but to another invisible one. This may be done as
follows ;

Introduce the black strip of card that has been mentioned
before, till it covers the mirror at 7 ; this will take away the
strong reflection of light which overpowers the feeble illumi-^
nation of the rays 1,2, 3 ; and the real hitherto eclipsed
primary set belonging to the secondary one with a white
centre, will instantly make its appearance with a black one.
We niay alternately withdraw and introduce again the strip
of cardj and the centre of the primary set will be as often
changed from one colour to its opposite, but the secondary
set, not being dependent on the rays 6, 7, will not be in the
least affected by the change.

If the contact should have been such as to give both sets
with orange centres, the introduction of the strip of card
will prove that the set which is primary to the other has
really a green centre.

Another way of destroying the illusion is to expose the
same arrangement to a brighter light, and at the same time
to increase the obliquity of the angle of incidence : this will
give a sufiicient reflection from the surface of the glass to
be no longer subject (o the former deceptive appearance ;
for now the centre of the primary set will be black, as it
pught to be,

XXJL Of

184 Experiments for investigating^

XXII. Of the reflecting Surfaces,
The rays of light that form rings between glasses must
undergo certain modifications by some of the surfaces
through which they pass, or from which they are reflected j
and to find out the nature of these modifications, it will be
necessary to examine which surfaces are efllicient. As we
see rings by reflection and also by transmission, I shall be-
gin with the most simple, and show experimentally the
situation of the surface that reflects, not only the primary,
but also the secondary sets of rings.

Upon a slip of glass, the lowest surface of which was de-
prived of its polish by emery, I laid an object-glass of 21 feet
local length, and saw a very complete set of rings. I then
put the same glass upon a plain metalline mirror, and saw
likewise a set of them. They were consequently not reflect-
ed from the lowest surface of the subjacent glass or metal.

It will easily be understood, that were we to lay the same
object-glass upon a slip of glass emeried on both sides, or
upon an unpolished metal, no rings would be seen. It is
therefore neither from the first surface of the incumbent ob-
ject-glass, nor from its lowest, that they are reflected ; for
if they could be formed without the modification of reflec-
tion from the upper surface of a subjacent glass or metal,
they would still be seen when laid on rough surfaces ; and
consequently, the efficient reflecting surface, by which we
see primary sets of rings, is that which is immediately un-
der the point of contact.

To see a secondary set of rings by reflection, is only att
inversion of the method of seeing a primary one. For in-
stance, when a lens is laid upon a looking-glass, the course
of the rays. represented in figure 8, will show that the rays
1, 2, 3, 5, 6, by which a secondary set is seen, are reflected
about the point of contact at 3, and that the lowest surface
of the incumbent lens is therefore the efficient reflecting
one ; and thus it is proved, that in either case of seeing re-
flected rings, one of the surfaces that arc joined at the point
of contact contributes to their formation by a certain modi-
fication of reflection.

xxiir. Of

the Cause of coloured concentric Rings, IS9

XXITT. Of tlie transmitting Surfaces.

.Jt would seem to be almost self-evident, that when a set
of rings is seen by transmission, the light which occasions
them must come through all the four surfaces of the two
glasses which are employed ; and yet it may be shown that
this is not necessary. We may, for instance, convey light
ii^io the body of the subjacent glass through, its first surface,
and let it be reflected within the glass at a proper angle, so
that it may come up through the point of contact, and reach
the eye, having been transmitted through no more than three
surfaces. To prove this I used a small box, blackened on
the inside, and covered with a piece of black pasteboard,
which had a hole of about half an inch in the middle. Over
this hole I laid a slip of glass with a 56-iuch lens upon it ;
and viewed a set of rings given by this arrangement very
obliquely, that the reflection from the slip of glass might be
copious. Then guarding the point of contact between the
kns and the slip of glass from the direct incident light, I saw
the rings, after the colour of their centre had been changed,
by means of an internal reflection from the lowest surface of
the slip of glass ; by which it rose up through the point of
contact, and formed the primary set of rings, without ha-
ving been transmitted through the lowest surface of the sub-
jacent glass. The number of transmitted surfaces is there-
fore by this experiment reduced to three; but I shall soon
have an opportunity of showing that so many are not re-
quired for the purpose of forming the rings.

XXIV. Of the Action of the first Surface,

We have already shown that two sets of rings maybe seen
by using a lens laid upon a slip of glass ; in which case,
therefore, whether we see the rings by reflection or by trans-
mission, no more than four surfaces can be essential to their
formation. In the following experiments for investigatinor
the action of these surfaces I have preferred metalline reflec-
tion, when glass was not required, that the apparatus might
be more simple.

Upon a plain metalline mirror I laid a doubk convex lens,

having

196 Experiments for invesiigating

having a strong emery scratch on its upper surface. Wheii
I saw the rings through the scratch, they appeared to have;
a black mark across them. By tilting the lens, I brought
the centre of the rings upon the projection of the scratch,
so that the incident hght was obliged to come through the
scratch to the ritigs, and the black mark was again visible
upon them, but much stronger than before. In neither of
the situations were the rings disfigured. The stronger mark
was owing to the interception of the incident light ; but
when the rings had received their full illumination the mark
was weaker, because in the latter case the rings themselves
were probably complete, but in the former deficient.

I placed a lens that had a very scabrous polish on one
side, but was highly polished on the other, upon a metalline
mirror. The defective side being uppermost, I did not find
that its scabrousness had any distorting effect upon the rings.

I splintered off the edge of a plain slip of glass 5 it broke
as it usually does with a waving striated, curved slope com-
ing to an edge. The splintered part was placed upon H,
convex metalline mirror of 2-inch focus, as in figure 10.
The irregularity of the striated surface through which the
incident ray 1,2, was made to pass had very little effect
upon the form of the rings ; the striae appearing only like
fine dark lines, with hardly any visible distortion ; but when,
by tilting, the returning ray, 2, 3, was also brought over the
striated surface, the rings were much disfigured. This ex-
"pcrimcnt therefore seems to prove that a very regular refrac-
tion of light by the first surface is not necessary ; for though
the rings were much disfigured when the returning li^ht
came through the splintered defect, this is no more than
what must happen to the appearance of every object which
is seen through a distorting medium.

I laid the convex side of a plano-convex lens 2*8-incIi
focus with a diameter of 1*5 upon a plain niirror, and when
I saw a set of rings I tilted the lens so as to bring the point
of contact to the very ti\gQ of the lens, both towards the
Fight and from the 'light, which, on account of the large
diameter of the lens, gave a great variety in the angle of
incidence to the rays which formed the rings ; but no diffe-
rence

the C&use of coloured concentric Rings, I2f

rence in their size or appearance could be perceived. This
seems to prove that no modification of the first surface in
which the angle of incidence is concerned, such as refrac-
tion and dispersion, has any share in the production of the
rings, and that it acts merely by the intromission of light ;
and though even this is not without being influenced by a
change of the angle, it can only produce a small difference
in the brightness of the rings,

A more forcible argument, that leads to the same con-
clusion, is as follows : Laying down three 54-inch double
convex lenses, I placed upon the first the plain side of a
plano-convex lens of f inch focus ; upon the second, a
plain slip of glass ; and upon the third, the plain side of a
plano-concave lens also |- inch focus. I had before tried
the same experiment with glasses of a greater focal length,
but selected these to strengthen the argument. Then, as
nothing could be more different than the refraction of the
upper surfaces of these glasses, I examined the three sets of
rings that were formed by these three combinations, and
found them so perfectly alike that it was not possible to per-
ceive any difference in their size and colour. This shows
that the first surface of the incumbent glasses merely acts as
an inlet to the rays that afterwards form the rings.

To confirm the idea that the mere admission of light
would be sufficient, T used a slip of glass polished on one
side but roughened with emery on the other : this being laid
upon a 21 -feet object-glass, I saw a set of rings through the
rough surface ; and though they appeared hazy,, they were
otherwise complete in figure and colour. The slip of glass
when laid in the same manner upon the letters of a book
made them appear equally hazy; so that the rings were
probably as sharply formed as the letters.

Having now already great reason to believe that no modi-
fication, that can be given by the first surface to the inci-
dent rays of light, is essential to the formation of the rings,
I made the following decisive experiment :

Upon a small piece of looking-glass I laid half a double
convex lens of l6-inches focus, with the fracture exposed
to the light, as represented in figure 11. Under the edge of

tke

1?8 Experiments for investigating, &c.

the perfect part of the lens was put a small lump of wax^
soft enough to allow a gentle pressure to bring the point of
contact towards the fractured edge, and to keep it there.
In this arrangement it has already been shown that there are
two different ways of seeing two sets of rings : by the rays
], 2, 3, we see a primary set; and by 1, 2, 4, 5, the secon-
dary set belonging to it : by the rays 6, 7, 2, 3, we' see a
different primaiy set ; and by 6, 7, 2, 4, 5, we see its secon-
dary one. That this theory is well founded has already been
proved ; but if we should have a doubt remaining, the in-
terposition of any small opaque object upon the looking-
glass near the fracture will instantly stop the latter two sets
of rings, and show the alternate colours of the two sets that
will then be seen by the rays 1, 2, 3, and 1, 2, 4, 5. Re-
move in the next place the stop from the looking-glass, and
bring the second shadow of the penknife over the primary
set, and there will then only remain the two sets of rings
formed by incident rays which come from 6, and which
have never passed through the upper surface of the lens.
Now, as both sets of rings in this case are completely form-
ed by rays transmitted upwards from the coated part of the
looking-glass without passing through the first surface of
the incumbent lens, the proof that the modifying power of
that surface is not required to the formation of the rings is
established.

It can hardly be supposed that the first surface of the
lens should have any concern in the formation of the rings
when the rays are reflected from the looking-glass towards
the eye; but the same experiment, that has proved that this
surface was not required to be used with incident rays, will
show that we may do without it when they are on their re-
turn. We need only invert the fractured lens, as in figure
3 2, when either the rays 1, 2, 4. 5, or 6, 7, 2, 4, 5, will
convey the image of the rings after their formation to the
eye without passing through any part of the lens.

[To be continued.]

xxvr. Ob-

JcXVi. Olservations upon Sulphurous Mineral WaterSi \
By M, Westrumb*.

jyi. Westhumb has been employed in making researches
upon several kinds of sulphurous waters, and latterly upoii
those of Eilsen in the county of Schaumbours:. '" ^ ^

One of the most interesting facts he has discovered is, that
all sulphurous waters contain a greater or less quantity o£
hydro-sulphuret or hme.

In order to ascertain it, he boiled the mineral water ex-
cluded from the contact of the air, in order to expel from it
the sulphuretted hydrogen gas and the carbonic acid.

He afterwards poured into the residue—

1st, Sulphuric acid, which liberated sulphuretted hydro-
gen gas from it ; and sulphat of lime was precipitated.

2d, Smoking nitric acid, which separated sulphur from it.

3d, Oxalic acid, which liberated sulphuretted hydrogen
gas from it; and oxalate of lime was formed.

4th, The water evaporated with the contact of ^he dlf^
precipitated sulphat of lime; and the sulphuretted hydro^ii
gas was liberated.

In order to determine rigorously the quantity of the sul-
phuretted hydrogen gas and of the carbonic acid, M. West-
rumb proceeds in the following manner : — He introduces
sulphurous water into a matrass to a certain point, putting a
mark upon the level of the liquid ; he adapts a curved tube
to it, entering into a long cylinder, which is at one time
filled with lime-water, and another time with acetate of lead,
with excess of acetic acid.

The apparatus being thus arranged and well luted, he boils
the water, and continues the ebullition until there is no
more gas liberated.

In the first experiment it is the carbonat of lime which is
precipitated, 20 grains of which correspond to ten cubic
inches of carbonic acid; and in the second case it is oxidated
hydro-sulphuret of lead, 19 grains of which indicate ten
cubic inches of sulphuretted hydrogen gas.

* From M. Gehl^n's new Journal of Chemistry, vol. v.
Vol. 30. No. 1 1 8. March 1 808. I Another

iSO Ohservatiojis vpon Sulphurous Mineral IVatcrs,

Another observation equally remarkable concerns the suvT-
phtirettcd hydrogen gas.

M. Ginibernatj a Spanish chemist, has asserted, that the
hot springs of Aix-la-Chapelle contain sulphuretted azotic
gas, — M. Schaub attempted to extract it from the sulphu-
rous waters of Nenndorf in Hesse. The following charac-
ters have been attributed to this gas : — 1st, A smell similar
to the sulphuretted hydrogen gas; 2d, Being indecomposa-
ole by the carbonic acid gas ; 3d, Not being inflammable ;
♦Jth, Being improper for supporting an inflamed body ; 5th,
Being indecomposable by the nitrous gas ; 6ih, Being de-
composed by the concentrated nitric acid, which separates
sulphur from it; Jth, Decomposing the metallic solutions,
and forming sulphurets ; 8th, Having a great affinity for
water, from which it cannot be separated, except by long
ebullition.

But M. Westrumb has found that when we wash sul-
phuretted hydrogen gas with lime-water, or when we pass a
current pf this gas through slaked lime, it acquires all th^
above properties.

Whether the sulphuretted hydrogen gas be obtained from
sulphurous waters, or be prepared in any other way in use,
the same phaenomena take place.

On bringing back t!ie lime-water by an acid, sulphuretted
hydrogen gas is liberated, which is inflanniiable, and which
possesses its ordinary properties.

Sulphuretted azotic gas is therefore a product of the ope-
ration.

M. Westrumb does not yet know if this new gas be pro-
duced by the action of quick-lime upon sulphuretted hydra-
gen o-as, or if this substance does not contain sulphuretted
azote.

Lastly, a third observatron not less interesting Is the pre-
sence of carbon aiid carbonated substances in the sulphu-
rous mineral waters.
' ":M. Westrumb has discovered a new principle In them-^
0, fetid resin of sidpfnir, (Stlnkendes schwefelharz.)

In order to obtain it, we must evaporate the sulphurous
-^ater excluded froui fhe contact of the air, and afterwards take

Otservdtions Upon Sulphurous Mineral Waters* 131

tJp the residue by alcohol, which dissolves this resin more
X{\k\\ the earthy niuriates. By the evaporation of the alco-
holic liquid, the substance at first looks like a yellowish fat,
it it successively coloured brown, and becomes resinous.

By repeated solutions in alcohol, and by evaporations, it
is decomposexl into sulphur, and into a' resin of a blackish-
brown.

It has a garlic smell, which becomes very strong, and si-
milar to assafcetida, when we pour water into the alcoholic
solution.

Its solution acts like an acid.

Its tcsin is dissolved in ammonia, and communicates a
yellow colour to it; the liquor acts like that of Beguin.
With lime-water wc obtain a hydro-sulphuret. All these
solutions act upon the metallic combinations like sulphuret-
ted hydrogen.

As sulphurous mineral waters have their orFgin in beds of
pi't-coal, we might perhaps find the source of this bitu-
minous principle in pit-coal itself.

Around the baths of Eilsen,- like those of St. Amand,
there is accumulated a kind of crust, which gradually be-
comes of a dark colour, and latterly black.

By analysis, there have been extracted from it sulphuretted-
fetid resin, hydrq-sulphuret of lime, sulphur, lime, alu-
mine, magnesia, charcoal, and sand, with some fibrous
substances, a little sulphuretted hy.drogen gas, and car-
bonic acid gas.

Whatever be the origin of the bituminous principle in
sulphurous waters, M. Westrumb succeeded in producing
charcoal and fetid resin, by employing sulphur perfectly
pure.

For this purpose he digested sulphur precipitated by an
acid in alcohol. By distilling the alcoholic liquor, there i.*
separated yellow crystalline sulphur, or a yejlovvish gray
powder : the fetid resin is then completely formed in the
liquor floating above, and possessing all the above proper-
ties.

We might attribute its formation to the presence of the

alcohol, and dfortioriy because, softer its separation- fiv)m the

i^O .1!///:, I 2 residue

132 Olservations tcpon Sulphurous Mineral IFaters.

residue of the evaporated sulphurous water, the penetrating
arnell is manifested, when it is taken up by the alcohol.
But several observations lead M. Westrumb to think that
the alcohol does not contribute to the formation, and that
it rather derives its origin from the sulphur itself.

Letter ofM^RoLOFF, of Magdehourg, upon the foregoing
Suljj^ct^,

I HAVE recently recognised in an unexpected manner the
sulphuretted fetid resin of M. Westrumb.

M. Michaelis, after having precipitated the golden gul-
phat of the hydrogenated sulphuret of antimoniated potash,
evaporated the liquor floating above containing the sulphat
of potash. '

When the ley began to concentrate, a vapour was deve-
loped, which very much embarrassed the artist who was
stirring the mass. There was at the same time manifested
an insupportable smell, analogous to that of burnt assa-
foetida.

The saline mass evaporated to dryness had a gray colour,
and the remarkable smell we have mentioned.

It was put in digestion with alcohol, which acquired the
taste and smell of garlic.

The alcoholic liquor evaporated spontaneously, yielded a
gray gluey rar.ss, possessing the same smell and taste,

I am desirous that this experiment should be made pub-
lic, not knowing if M. Westrumb is acquainted with the'
formation of a large quantity of fetid resin which may be
easily procured by this process.

As the smell is mainifested before putting in the alcohol,
we may conclude, with M. Westrumb, that the alcohol does
not contribute to its formation.

■ "* From Gehlen's cevv Journal of Chemistry.

XXVII. On

XXVII. O/z the Preparation of CalomeL r

j^j i>y Mr. Joseph Jewel.

'In our last number, page 93, we mentioned that Messrs.
Howard and Co. had introduced an important improvement
in the preparation of this essential article of the pharmaco-
poeia. It is the discovery of Mr. Joseph Jewel, one of the
partners, who gives the following specification of his in-
vention, for which he has taken out a patent : __„ -

'^ Calomel, or mercurlus dulcis, as usually prepared, is
at first a hard crystalline substance, and requires to be
pounded and triturated with water, either in a mortar or on
a slab with a muller, or in a mill. After having been
ground or triturated for a considerable time, more water
is added, and the whole well stirred up. The finer particles,
which remain suspended for a short time, being poured off
with the water into another vessel, and left to subside, the
water is then decanted, and the fine powder dried for use.
The coarser particles arc again submitted to the operation of
grinding and washing ovcr^, until the whole be finished.
Now the nature of my invention is to produce the effect of
the grinding or trituration above described, in a more per-
fect manner, during the last sublimation of the calomel ;
which I do as follows : ■ '' *^ ''■"^'*' o

*' I take calomel, or mercurius dulcis, broken into small
pieces, and put into an earthen crucible of the form of a
long barrel, so as to fill about one half thereof. I place the
crucible on its side in a furnace provided with an opening,
through which the mouth "of the crucible projects about an
inch. I then join to the mouth of the crucible an earthen-
ware receiver, having an opening at its side to receive ihe
open end of the crucible. This receiver is about half" filled
with water. I lute the joint with a mixture of sand and
pipe-clay. The receiver has a cover, v/hich cover has a side
continui'd upwards for containing water, with a chimncv or
tube in it, to allow the escape of steam from the water be-
low. I then apply a fire around the crucible, sumcient to
rai^e the calomel in vapour, and force it through the mouih
.of the .crucible into the receiver; v. here, by the water,*
^^ J 3 while

134 On ike Cknitractiorl which takes place in Mercury

while cold, or assisted by the steam when it tjecomes hot,
it is instantly condensed into an impalpable powder, pos-
sessing all the qualities of calomel in its most perfect state.
The calomel, when thus prepared, is purer, whiter, and
more attenuated, than that obtained by grinding. It is
proper to wash the product over with water, before it is
dried, to rid it of any coarser particles which n^ay forip
about the mouth of the crucible.

XXVIII. On the Contraction which takes place in Merciiry
at low Temperatures by, Ahstrcctlon of Heat ; — and on the
JRatio of Contraction between Mercury, Alcohol, Water^
and Silver. By John Biddle, Esq, of Birmingham,

Birmingham!!, Fp]t)ruary, 1808.

To Mr, TiMoch,

SIR,

-^ LETTER frorri M. Tardy de la Brossy, dated Joyeuse,
(Ardeche) October 13th, 1805, addressed to Professor Pictet,
of Geneva, has appeared in your M.'^gazine [vol.xxiv. p. 322] .
It contains observations on some experirncnts which I had the
pleasure of showing to the Philosophical Society here on the
specific gravity of mercury in its frozen state, which experi-
inents were communicated to. the public through the me-
dium of Mr. Nicholson's Journal for April 1805. The
observations of M. Tardy de la Brassy have induced me tp
look over the original papers, containing the results of
those experiments, with som^. atUntion; and, with deference
to the opinions of that gentleman (though I fc^ar spme in-
accuracy exists), I must, in defence of my experiments ge-
nerally, and the deductions piade from them, request you
to commvmicate a fe\v experiments and olpservations through
the channel of your Magazine.

M. Tardy dc la Brossy, after a^vowing tb^ object of his
communication to be *' the extension of truth, and the re-
moval of error,**, proceeds to describe the result of some of
mv former experiments, and to make his obscpvations on
iny calculations trom them, to which I wpuld refer; but if

" ' , ' ' ' ' - ^

at low Temperatures, 135

he had added experiment to his calculations, he would have
been convinced that the principles on which I proceeded are
just, and that one source of difference in our opinions
arises from the partial application of the mode of reasoning
which he uses. For, admitting with him the specific gravi-
ty of the alcohol employed to be '810 nearly, or -814 1 where
water is 1*000, and that 1000 grains of mercury would exhihi^
^lossofweiglit in alcohol of the temperature stated, of 39*8,
when weighed by the hydrostatic balance, vet it does not ap-
pear to me necessary to suppose, a priori, so long as each
of these substances remains in a fluid state, that the ratio of
their densities should differ when uniformly subjecicd to the
lower degrees of heat. As, however, my fornier experiments
were not made with a view to discover the contraction of
the volume of the alcohol, I made no observation relating
to it, and now think it right to investigate the subject by
experiment.

A. I first distilled mercury as before, with great care,
using only that 30 per cent, of the whole which first came
over in the distillation, esteeming it the most pure. I found,
by the hydrostatic balance, the specific gravity of this to be-
13*613, as 1000 grains lost in distilled water 73*4 at the tem-
perature 50 of Fahrenheit's scale.

B. I took alcohol frou) the same parcel which I had used
in my former experiments, and filling a light glass bottle
formed with a long narrow neck for the purpose, it was lound
to weigh 'SMI, when water weighed- 1 -000 at the tempera-
ture of 48° nearly.

C. Having obtained a mass of very pure silver, procured
from luna cornea, 1000 gr. lost in distilled water 07s, the
specific gravity of which was thereby found to be 10'225; but
bv hamn)ering it into a form convenient for mv purpose the
specific gravity increased to ]0'3C)'-2, the loss of ut-iohf Ut'in^
{)Cy9 at 30® of temperature. At the following tempera-
tures the variations of loss of weight- are expressed in the
second column, the conse<pient specific gravities in the third,
according to the usual uhkIq of calculation, and in the
fourth is shown the loss of weight in alcohol .-—parts of a
series of observations from experiments, that are given niore

^a. , . J 4 at

13§ On the Contraction which takes place in Mercury

at large in the table containing a general comparison pf thQ
several experiments.

1

2

3

4

Dejjfrcea of heat

liOss cf wc!i>ht

Specific gi'aviiY
of siKcr whrn
water is 1-000.

Loss of v.'ci<;-hl

according to

Fahrenheit's

scale.

of 1000 p-. of

.'ilveria distil! eu

water.

oflOOOj,rr,o/sii-

ver weighed in

alcohol.

200

94

10-63S

185

9^-4

10-593

173

94-6

10-5/0

158

95''2

10-504

150

95-3

10'4y3

130

95-5

10-471

75-4

302

95-9

10-42S

76-2

80

96-3

10-334

77-6

66

96-4

10-373

78-5

55

06-4

10-373

50

96-3

10-362

78-0

34

965

10-362

79-4

21

—

:

60

9

—

80-5

0

—

-^

81

20

—

81-6

32

—

;

.82-5

5\

—

83

5Q

—

83-1

D. By the following experiments I then proceeded tQ
ascertain the specific gravity of mercury and silver at various
temperatures, from 1 00'^ above zero to more than 40° below
it, with a wish to obtain a ratio of contraction between mer-
cury and silver, and between eacVi of the§e and alcohol.
For this purpose two hydrostatic balances were so placed
that the metals suspended from thern might fall into a glass
vessel containing alcohol.

I then attached 1000 grains of silver to one balance, by
a wire 12 inches long, weighing only iV ^^ ^ grain;
and to the other 1000 grains of. mercury, in a small glas^i
bucket weio;hing lOl-jSg. grains, suspended by a wire nearly
4 inches long, weighing y^- grain.

Then also suspending in the alcohol a good thermometer,

marke4

'*.■ ••• V <1^ low Tejnperatures, "^^^ ^^ 187

marked for low temperatures, and having provided a quan-
tity of murij^te of lime and snow, I reduced the temperature
of the alcohol and metals, as in my former experiments the
subject of M. Tardy de la Brossy's observations, and ob-
tained the results expressed in the following table.

'

2

■^' 1

4

5

6

7 '

^ — ^

■*.,_ —

U- 4J

^i

C O ,3

3 a< o •-

i a,

O u

o U

o

^ 2 ^ \

^-■o S^

«^-§s

^-^J «?^

>^'%9

" o ^

.xz-7. 8 ^

//> —

^ u to

^ 0)

.- tj h 1

pecific grav
Ivcr if theal
oes notincre
ensity.

1 ^11 I

if o '-i

^ '-' ;■«

•5 ""To •

o5

g2-2 . 1
11 il

CO -^ •:;-rJ

J -. & ^ J2

h 5^

-;^ ^^

-,-5 rt -

H^ b

cfi c-o.S

1(V6B0

76-2

100

82-6

24-3

58-3

13-963

10-318

77-4

60

85-0

25-3

59-7

13-63t>

10-36:2

78-56

50

85-3

25-3

59-8

13-613

10-359

78 3

44

85-5

25-6

59-9

13-589

10-208

79-7

20

86-6

^C)

60-6

13*433

10' £90

79-9

6 or 7

86-7

26-1

60-6

13-433

10*037

81-1

0

86-9

26-2

60-7

13-411

In an examination of the 1st and 2d columns of this
table relating to silver, it being previously known that
10*362 is the specific gravity of silver, and that -8141 is ihe
specific gravity of alcohol at 50^ of Fahrenheit, where watej^
\s !-000, it appears, following the general mode of calcu-
lation in which the loss of weight is made the divisor
pf the quantify weighed, and the quotient expresses the
specific gravity, thai as at 100 degrees of heat the divisor
for the quantity of metal is less, apd at zero greater, that
at zero the specific gravity is less, and at 100 degrees above
it the specific graviiy is greater : — A conclusion opposing
a general law, which therefore we cannot admit.

'I'o account for this apparent inaccuracy of result, we
must direct, our attention to the alcohol employed, and
see if, in the comparison of the /?//./"(y alcohol and the solid
gilver, this appearance of contradiction to an established law
does not arise from the contraction of the fiuid. Of this it
will be ditficidt to bring visible proof to the extent required;
tor if I put into a glass tube alcphol, of wljich the weight is

known.

138 Oft the Contraction which takes place in Mercury

known, and expose it to dificrent temperatures from 100
to 50 degrees, it will contract ; but whilst the fluid con-
tracts, the glass which contains it contracts also, and shows
only the difference of the contraction between the fluid and
glass : — however, as we know that silver by hcatiniir cannot
become specifically heavier, or by cooling specifically lighter,
in these experiments which are evidently a coniparison of
densities, the alcohol mu»t become more dense by depriva-
tion of heat.

The third column of this table contains the temperatures.

In the 4th column the 1000 gr. of mercury and the glass
bucket containing it appear together to have varied at the
two extremes in loss of weight 4-3.

By the 5th column it is shown that the glass bucket alone
varied at the two extremes in loss of weight rg.

By the 6th column it appears that 2*4 only can be stated
to belong indispensably to a variation of the respective den-
sities of the mercury and alcohol in the changes of tem-
perature from 100° to zero. The other variations, J presume,
arise from some inaccuracy, such as making the observa-
tions when the fluids w^re at different temperatures.

By the 7th column are shown the different gijiccific gravi-
ties of the mercury, by calculation from the loss of weight,
supposing the density of the alcohol the same throughout :
f;om this it appears that the density of mercury is greatest
at the highest temperature, and least at the lowest ; but
as this cannot be actually the case, it is obvious that the
alcohol increases in density ; and this appears also from the
results of the 2d column relating to. silver, at C.

For the specific gravities or alcohol at various tempera-
tures, 1 must refer to the calculations at L, made from the
following experiments, and which are contained also '\\\ a
general table of results.

E. I procured the bladder of a rabbit, and washed it well
with alcohol. It weighed 7 grains in air; and having an-
nealed a wire about 9 inches long, the weight of wliicli was
-,«f,lhsof a'grain in air, I found that 'the bladder and wire,
when sunk in alcohol to a certain mark on ilie wire, weighed
2'5 grains only, at tlic temperature Ab^,

4 This

at low Temperatures, 139

This bladder was filled with mercury, not quite pure,
then suspended by the wire 5 and when one end of the wire
was attached to the balance, it was found to contain 5276
grains; weighed in alcohol, it lost 321*5, from which de-
ducting the weight of the bladder and wire in alcohol, 2-5,
it appears that the loss of the 5276 grains of mercury, whea
rhe thermometer is suspended in the alcohol

at 45° of temperature, is SI 9

93 -^ —

100 — —

J12 — —

118 — —

125 — ^

130 — ^^

\

135 ... .^

130 -r- -r-

125 -r- ^

123, r— —

120 — «^

118 — —

117 -^ -r-

113 — —

111 ^ —

|08 — -r-

104 T- —

100 r- •—

97 — —

93 — —

ey — —

85, r- —

83 — —

80 — —

78 — —

76 — —

^ 7Q — —

$8 ^ ^

315 le

ss by

4

312

—

7

311

—

8

309

—

10

308

—

11

307

—

12

306-5

S06

306-5

—

12-5

rThe alcohol now in
1 q J agitation by the heat
"^S could make nohigher
(^observation.

12-5

307

—

12

307-5

—

11-5

308

—

11

308-5

—

10-5

309

—

10

309-5

—

9-3

310

—

9

310-5

—

8-5

314

—

8

^

311-5

—

7-5

•>

312

—

7

312-5

—

6-5

313

—

6

313-5

—

5-5

»

314

—

5

• f

315

—

4

316

—

3

,:

317

—

2

317-5

—

1-5

2\U

-r-

X

. i

140 On the Contraction which takes place in Mercury

at 65 the mercury loses 318'5 less by 0-5

62 — — 3iy _ 0

50 — — 320 more by 1

45 — ., — 320-5 — 1-5

40 — — 321 — 2

36 — — 321-5 — 2-5

^4 — — 322 — 3

27 — — 323-5 — 4-5

14 — — 324 — 5

5 ^ — 324-5 -— 5-5

O — — 325-5 — 6-5

5 below zero 326*5 — 7*5

J8 — — 327-5 — 8-5

21 — — 328 — 9

We may observe in this experiment that some difference is
cJccasioned by the direction in which the heat passes,
whether from without to the alcoliol, and thence to the
mercury, as in the first part of these observations from
45® to 135^; or from within from the mercury to the al-
cohol, as from 135^ lo zero and 21'' below : and it appears
that the temperature was not the same in these two fluids
when the observations were made j for when I weighed the
same mercury with a hole in the bladder to introduce the
bulb of a thermometer, that I might observe the variation
of loss of weight when the alcohol and mercury were at the
same temperature exactly, it showed the mean of these va-
riations to be correct. So that in comparing 52/6 parts of
mercury with alcohol, there is a variation in the contraction
of these two fluids expressed by 22 of loss of weight in
passing through 156 degrees of temperature. In comparing
1000 parts of mercury with alcohol, it follow:^ that there is
a variation of loss of weight in 156 degrees of temperature
expressed by 4' 17, which shows -0267 is the loss of alcohol
in each degree greater than that of mercury.

If Uiese two fluids were to contract by deprivation of heat
in the ratio of their specific gravities, it is obvious tliat the
Joss of weight shown by the hydrostatic balance would be the
same throujih all the changes of temperature, the changes
Ibting the &amc in both fluids at the lime of obscrvatfon.

It

at hid Temper aturei, ^ 141

It is therefore of matcFial consequence to this inquiry to
know in what degree equal bulks of mercury and alcohol
increase together, without the hydrostatic balance denoting
the alterauon by any change of loss of weighty for this
purpose we must look to D, and forward to the experiment
G, and the calculations from them at L and \, where we
shall find a rule for discovering the specific gravity of al-
cohol.

F. To find the proportion of contraction between mercury
and water, I took 3024 grains of mercury in a bladder, as
before ; and weighing it in distilled water by the hydrostatic
balance, the mercury and water heated to the temperature

200themercuryIost2i7-4i:t.Tun:Si:fT^™!

193

*—

217-6 (

^thewaterhavingrisen

^90

185

—

217*8^

in vapour and con-
densed on the balance.

■ —

218

1 80

—

218-2

175

—

218-4

170

—

218-6

J

165

—

218-8

160

—

219-1

135

—

219*4

150

—

219*7

145

—

220

133

—

220-3

130

—

220-4

123

— •

220-5

120

—

220-6

110

—

220-8

98

—

• 221-1

88

— ,

221-3

78

—

221-5

^8

—

221-7

"

5^

—

221-9

50

—

$22-1

Thus, at 200° of temperature mercury would

appear of greater

specific gravity than

when- at

50°, following the general

mode of calculation;

but if we suppose the water is more

i

contractejl

142 On the Caiitr action which takes place in MercunJ

contracted than mercury by abstraction of treat, and attri-
bute to that the difference of loss of weight, then, in com-
paring 30i24 of mercury with water, there is a variation in
the contraction of these two fluids expressed by 4*7 loss of
weight in passing through 150 degrees of temperature. In
comparing 1000 of mercury with water, a variation of loss
in 150* is expressed by l'554i?.

G. The following experiment was made before many of
my philosophical friends with mercurv, described before, of
the specific gravity of 13*613, suspended by a very fine wire
10 inches long, weighing only ^V of a grain ; — the baro-
meter standing at 29*8, the thermometer at 35.

1000 grains of mercury with 750 grains of alcohol, as be-
fore described, were put into a thiri glass vest^el, made for
the purpose, round at the bottom, and increasing in diameter
gradually to near the top, so that the mercury might l«e
easily suspended in the alcohol by a wire introduced into it
whilst fluid. These were placed in the centre of a mix-
ture of 4 pounds of snow and 4 pounds of muriate of lime,
at If o'clock at noon : at 5 minutes past a thermometer
placed in the frigorific mixture fell to 5^° below zero, then to
54 and to 60. The mercury in the tube of the thermome-
ter appeared frozen : it was withdrawn, and when exposed
to the air a few seconds, suddenly fell to 140*^ on the scale,
in consequence of the mercury in the tube again becoming
fluid, and occupying the vacuum which had been occasioned
by the contraction of the mercury in the bulb after that which
was in the tube had become solid : it was then immediately
returned to its place in the mixture of snow and nmriate of
lime ; it had remained at 1 40° for several minutes when taken out
and exposed to the air, so that the mercury still in the tube was
airain made fluid j it instantaneously sunk into the bulb
much below 270^, the lowest point on the scale. During
this time the mercury and alcohol, very much reduced in
temperature, were removed from the above mixture^ and
placed in a second mixture of 3 pounds of snow and 3
pounds of muriate of lime : the whole was then placed in
the first mixture; and at the moment of the crystallization
of the mercury, the wire, already partly attached, was by

raising

at low Temperatures. 143

raising It gently, drawn from the side to the centre of
the surface of' the mercury. When it was fixed and the
whole was solid, it became necessary to withdraw the
glass, and expose it a moment to the air of the room, until
that paj-t of the mercury attached to the glasswas softened;
then, by keeping one hand drawing gently at the wire,
the whole oF the mercury was suspended, and, with the al-
cohol, immediately returned to its place in the cooling
mixture ; the mercury was now suspended from the hydro-
static balance by the wire fixed in it, and weighed with great,
accuracy ; — and the following observations were made from ;
the time the second quantities of muriate of lime and snow
were lilixcd.
In 5 minutes the mercury was crystallizing.

JO became nearly solid.

30 quite solid — withdrawn.

40 ^ having been replaced.

50 suspended in the alcohol, and

weighed by the hydrostatic balance with great care,

lost 60-8

6o minutes the mercury and alcohol having been a little

withdrawn, the mercury lost 6o
85 minutes the mercury lost 59*9 it was now so nearly

fluid, there was splendour on the surface.
130 minutes the mercury lost 60*8

1)5 CO-3

150 60-1

160 CO-3

( having been withdrawn,
1 70 • ■ ■ ■ ■ ' ■ 60* 1 ^ and the temperacureia*-

^ crease^.

175 — 60-r

180 61

As I could not decrease the heat so as to indicate a greater
loss than 6 1 , and my own body dufing these three hours having
suffered an unusual and partial deprivation of heat, I withdrew
the mercury and alcohol, not doubting, if it could have at^-
swert^d any purpose, by these means to have been able to
have kept the mercury solid some hours longer, the sur-
rounding substances having lost so much heat.
AVe see from the observations made in this expepimootj that

5U-9

144 On the Contraction which takes place in Mercury

59*9 is the least diminution in the weight of mercury when
weighed in a solid state in alcohol, and that it is at this moment
when their spccific'iiraviliesare furthest from each other; for we
may observe that at ahiiost the next degree of temperature to
that ill which the mfrcury loses its fluidity, v;hilst the alcohol
preserves its fluid form, the mercury appears to become of
less specific gravity, as it loses 60; which gives, according
to calculation at L, only 11 ; but the fact appears to me to
be, that alcohol proceeds m the ratio of a fluid by decrease
of temperature, and that mercury, having obtained a solid
form, follows the ratio of contraction of a solid ; therefore
their densities approach each other. I should have ascribed
this greater loss of weight to the particles of the mercury at
•the moment of .crystallization occupying, in consequence of
their new arrangement, more space than at the moment be-
fore it became solid, as with some of the metals is known
to be the case, had I not carefully observed the passage of this
metal in other experiments, where I had an opportunity of
seeing the contraction proceed very distinctly; and had not the
mercury, also proceeding to still lower temperatures, lost
from €0, 60-1, 60-3, GOT, 60-8, and 6l, long after the
whole had becoire solid, and was suspended by the wire :
thus, 61 is the greatest diminution of weight by the abstrac-
tion of heat which I could obtain, and I am of opinion that the
space described by these changes of loss of weight demotes a.
rangeofmany degrees of temperature: how much greater the
density may then be than that stated at L, I cannot presume
to say ; but as it takes, with some probability, a proportion
of contraction approaching to that of silver, it certainly appears
improbable thai it should reach the specific gravityvvhich my
former calculation Irom a single observation led me to at-
tribute to it. I am therefore inclined to believe there was
some inaccuracy in weighing the silver by the hydrostatic
balance, when by my former cxjKTiments I gave S8'I, the
quantity of loss of ICOO gr. of silver: — from many observa-
tions in this laborious train of inquiry, it seems hardly possible
that the former could have been correct; for if the alcohol and
silvercontinuedto contract inthe samcproportionfrom56°be-
low zero,as they do from64"aboYe zero to that temperature, it
would appear that an abstraction of heat must necessarily have

taken

..^50.^ ^^^ .^ ^^ femperaium. ^ ^^ ^^ lii'

tlkert pladi equal to 1^5^ mdre, o/'tpl 76^ below zero,
which I can hardly suppose, though the mercurial thermo-
meter used in these experiments fell lower than 270^*
below zero. If my former statement be erroneous^ it cer-'
tainly is not attributable to the mode of calculation, as ap-
prehended by M. Tardy de la Brossy. As it does not appear
that he had made any experiment on the subject, he could
not have anticipated this inaccuracy in the weight of silver:
and as he says that only a few grains of the increased gra-
vity of the mercury was attributable to the alcohol, he could
not be aware of the great increase of the specific gravity of
alcohol shown at I, by the same mode of calculation used'
in my essay, the subject of his animadversions. "-'"^

It is still, however, obvious, that mercury would not be
of the specific gravity which I attributed to it, unless it had
followed the same rate of contraction after it became solid a^
it did whilst fluid : tiie evidence of the increased loss of weight''
is so much against me, that I cannot defend that experi-
ment; and I would now be understood to carry my observa-
tions on the specific gravity of mercery, with accuracy, t'or
tbe point of congelation only; or to slate that near 56^ be-
low zero its specific gravity is 14*465, as by calculation at L,
Then, if we attribute to mercury in a solid state nearly'
double the contraction of silver as at H, or '00100 in each
degree, as it is near to its point of fluidity, we shall arrive
only at the specific gravity 14*483, as is shown at M.

To ascertain whether the silver at C, with which I pro-
posed to compare the mercury, had expanded or contracted
by the deprivation of heat to which it had been exposed,

H — I took an ingot of silver, \6 inches long, 2 inches
wide, and half an inch thick, weighing nearly 100 ounces;
and provided an instrument for the purpose of measuring
accurately the contraction and expansion of the silver,
by fixing in a piece of well baked wood two centre pins,
exactly 15 inches from each other, one of them very find,
for the purpose of striking an arch of a. circle on the surface
of the silver, when the other was fixeld in a perforation made
in the silver by the centre itself. Then, on the surface of the
bar of silver, heated to a pale red, an arch was described with

V^ol, 30. No. U8. March 1808. K this

14-6 On the Contract io?i irh'icJi lakes plfce in Mercury

this instruynent; and. when again reduced to the temperature
o]F50 degrees, another arch was drawn : — the contraction of
th^eiar of silver hetween the two points appeared to equal
•Birth part of its dimensions. T ,1'

I he silver wag then heated to 2CjQ*' of temperature of^
Fahrenheit's. ^sc^Tile, by boiling it in \vater, and gradually
coplmg; an, arch of a circle was then struck on the surface
of _ the silver :, reducing it to 150^ of temperature, another
arch was struck with the same unvaried centre pins, which
Showed evident contraction in the bar of silver: agaip, at
100° of temperature another arch was described ; and a
fourth, at 50^ showed that the silver had contracted in the
deprivation of 15(^^ of temperature -g-i^jth part of its length.
_ Tlien, similar parallelopipedbns being to each other as the
ciibes of their homologous sides, the increased specific gra-
vity, is shown "by multiplying the specific gravity at 50%
namely, 10'362, by the cube of v^41; and dividing it by, the
cube of 340^ which equals 10-4537; '0917, therefore, is
the difference \p.^ 150^ of heatj or '90061 14 is the contrac-
tion of silver in each degree; which, from the way this ex-
periment is perfqrnied, I call its visible contraction. From
it .the specific, gravities at the several' temperatures below
are calculated ; — /,„

At 200 _ silver is oi the speciijc gravity ] 0*2702; , ,

V^P/o 1, ■ 10-3908

135 10-3100

117 . 10-3210

100 \ 10-3314

j^"5p.^^ / , 10-3620

,' "of' 10-3925

50 below zero 10-4231

52 — . 10-4243

56 10-4268

I. Then, if 10-4268 be the specific gravity of silver at
56^ below zero, and weighed in alcohol at that temperature,
by. calculation from its loss of weight at C, it will appear
tgi be 9*796; by taking '8141 as the supposed density of al-
•cphol,, dividing the quantity 1000 by the loss 83-1, multi-
plying]; the quotient l£-033 by '81 41 ^ and dividing by 1-000,

the

:-m'>ts\'l^ K\ at do0^ Temperatures* - mO«^Vj^ 147

the specific gravity df-vv^ei-,^ the result bf this being 9'796;
What then is the speelfic gi-mity of the dicohol — if not 8141?

^ It is fbun(l|Vtl^i?:ru)e,;~

Divide 1000, the quantity weighed, by the loss of weight,
and by the quotient divide the density of silver, according
to its visible qontll^elion ; the quotient will be the specific
gravity of the alcohol, or fluid in which it is weighed.

».Xhus,at the temperature 56' below zero, ihc loss of weight
i#3i^*;l ) by whic));,t itrrJiOOO (the quantity weighed) be di-
vided, tl\e quotient is l^-OSS, by which 10-4268 (ihe density
^f silver, according to its visible contraction) is divided ; and
tl?^t^otient is '8665, the specific gravity of the alcohol at
56^ below zero. Thus, -0524 is the sum of variation of the
speciiic gravity of alcohol in 106% or 00049434 is the varia-
tip4j in each degree of temperature : from it the specific
grfiyities at these N^everal temperatures are calculated.

At 135^ the specific gravity of alcohol is -77208

>iJ} i: 117 -78098

j^EBp 100 — 4l-^c^ -78938

' 50 •' : ■ '" -81410

zero — -83882

50 below zero -66353

52 ■ -86482

56 -86650

K. Then taking the specific gravity of the alcohol at anv
certain temperature, and the loss expressed at C ; What will
be the specific gravity of the silver according to C ?

It is found by this rule : —

Divide 1000 (the quantity weighed) by the loss of weight,
and multiply the qudtient by the specific gravity of the al-
cohol or fluid in which it is weighed.

Thus, at 5Q^ below zero the loss of weight is 63-1, ac-
cording to C ; by which if 1000 be divided, the quotient is
12*0337 ; which, multiplied by "8665, the density of alco-
hol, as at I, in that temperature the product is 10-427, the
specific gravity of silver at 5Q' below zero.

Then, having ascertained the specific gravity of silver and

K2 of

I4t On the Contraction ivJdch takes place hi Mercunj

of alcohol at several points of the scale 6f temperature by
calculations at I, from ej^pcriments at H, the calculation of
ihe-spt'ct/Ic gravity of mercury is thus perforjiied : —

L. — Divide the quantity by the loss, and multiply the
quotient by the specific gravity of the alcohol at such tem-
perature.

Thus, mercury at G, in the temperature of 56^ below
zero, appears to be of the specific gravity 14-465. For divi-
ding 1000 by 59*9, the least loss in the solid state, and mul-
tiplying the quotient 16'694 by *S665, the specific gravity
of alcohol at that temperature^ the product is 14*465.

Then if mercury in 106% from 50^ above to Gb'^ below
zero, increases in specific gravity from 13*613 to 14*465,
namely *852, which gives *O0SO4 each degree; this sum,
multiplied into the number of degrees from 50^ above zero,
gives the specific gravity of mercury at that degree, if de-
ducted when above 50 from 13*613, or added to the same
when below 50^.

Thus at ISS'' above zero, which from 50° is 85% if the
sum *00804 be multiplied by 85, the product is *6834;
which subtracted from I^'6l3, the specific gravity of mer-
cury at 50% gives 12*9296, the specific gravity of mercury
at 135^ of temperature.

At 200° the specific gravity of mercury is 12*407

150 12*809

335 . 12*929

117 13*074

100 13*211

50 - — - 13*613

0 14015

50 below zero — — . 14*417

52 14*433

bQ 14*465

'Then, to see if the alcohol in which the mercury was weighed
at G obtains by the same mode of calculation a. specific gra-
vity, according with the calculations at I, from the experi-
ments at H on silver, — observe the rule at I.

At the temperature 5^^ below zero, the loss of weight is
59*9 on the quantity 1000; by which if it be divided, 16*694

is

(tt low Temperatures* 14^

i^ the quotient ; this again dividing the specific gravity of
the mercury 1 4*465, the quotient is at this temperature
•8665, the specific gravity of the alcohol according to G,
which agfecs with the calculations from the loss of
weight of silver by experiments at H, and calculations
at I, it there appearing that '86G5 is the specific gravity of
the alcohol.

M. Supposing the mercury weighed by the hydrostatic
balance at G in a solid form, during the variations in the
loss of weight from 59-9 to 61, to have passed through 20'
of temperature to 76^ below zero, and to have ipcreased
•<K)1 each degree, then mercury in a solid «tate will have
arrived at the specific gravity 14*485, and the alcohol in,
which it is weighed with a loss of weight of 61 will conse-
quently be of greater specific gravity.

For if alcohol at 56^ below zero was of the specific gra-
vity '8665, as at l^ the mercury losing 59*9, ^^s at G, and at
a lower temperature the same mercury weighed In the same
alcohol lost 61, it will appear that the alcohol must have In-
creased in specific gravity ; for if 59*9 be •8665, 61 will be
•8842, the mercury remaining at 14*465, as at L; but as we
have reason to state, it passes on to 14*485 at 76' below
?ero, then the specific gravity of the alcohol must appear
lobe '5854; because if 14*485 Increases '001 each degree,,
•8842 will increase 'OOOOei; which sum_, multiplied by 20,
equals -001220 ; this, added to '8842, equals -8854.

N. We observe at F, 3054 of mercury lose 222* 1 at 50^ of
temperature; at 200^ of temperature it loses 217*4; and by
calculations at L, the specific gravity of the mercury so
weighed was shown to be 12*407 at that degree of heat.

Then by the rule at I : —

If 3024 be divided by 217*4, the (juotlent is 13*909, which
sum dividing 12*407, the known gravity of mercury at L,
the specific gravity of the water will consequently appear to
be '8920 : this deducted from 1000, the specific gravity of
water at -50^ of temperature, leav?:s *10SO, the sum of dilTer-
rencc in 150 degrees^ and

K3 at

J 50 On the Contraction ivhkh lakes place in Mcrcurr/

At the following temperatures water is of the specific gra-
vity stated: 500^ r -8990

150 ^, .f)3()6

135 -,-_ 'iHli>

117 '9537

]{)() '(jc^Gl

' 50 ^ 1-0000

and as '1080 is the sum of difference in 150^, this sum
*0007£? expresses nearly the variation in each degree.

Wc find from !he data obtained in these experiments a
rat'fn of contracimn between mercury, alcohol, water, ai>d
silver of e(|ual volume.

Mercury at L is -00804

Alcohol at T is '0004943

Water from F above -0007200
Silver at II is •0006114

, What will he the proportionate contraction of each, that
gf mercury being supposed ICO?

As the increased specilic gravity of mercury is to the sup-^
posed number, so is the increase4 specific gravity of either
to the number required.

( 0004943 = ()'144 ContraciionofalcohGl

IfOOS04bel0O,wliatwilU;OO372OO=: 8-955, waler

/0006j14==7u04 silver

of equal voiun.e, when th.'at of macury is JOQ..

^'^ If- we suppose water to be 1 OOOO .7 ^ '*

*" ' ' then mercury will be IV 1^^^ ■

alcohol' • <^^ ^^'^-i'es^S
silver - ■'•6491'

As in the hydrostatic balance the comparison relates to
Qqual vahiines-u^' the thing weighed, and the fluid in which
. it is weighed ; What will be the ratio of contraction oi' eqi/al
weights of each of the above ?

As the specific gravity of cither is to the specific gravity
of mercury, so is the ratio of contraction of equal voKmics
to the ratio of contraction of equal weights.

As .*8M1 : 13613 :: 0004943 = 008265 alcohol.
I As 1-000: 13613 :: 0007200 = OO96OI AvateiV
As; 10'36i' : U6I.3 :; 0C06i 14 =000803 sifW.

OOSO'U) mi^r-eufy.

' Table

Table of Results of the foregoing Experiments^ with some
Calculations from them.

liic gravity of o/<o/jo/Cal-
ed from lossat C,and the
le contraction of silver
as at I.

iric gravity ofsilnr cal-
ed from loss at C, and its
le contraction at H as

ific gravity ot sih cr cal-
ed from its visible con-
ion at H.

X J3

41

n

re

i

of wcigiit (>f 1000. of
!/?•]/ weighed in alcohol
and G.

ihc gravity of meratry
ilatc<i from the various
ties of alcohol at E and
at I..

■SIS ■

Q W

II •

Spec
culat
visib
at H

/3 O >• rs

£
200

-4 S re

ai jy a re

tfl C fl

71-88

list

10-270

12^107

-8920

>t» h'i.'v

;

175

7226

10 300

l.';0

12-809

72*65

-9306

j^2d''

'16-240

10 310

135

75-4

130

58

12'929

7276

•9-il9

7810

io-2;6

10 321

7(>

117

58-47

13074

ci ii

i^

-•4

108

. ■ '■

7SCi3'

102/6

10331

\

-7
77

100
95

58-3

13-214

73-10

•9661

—•6

82

TfiOD 1C>

lon-i ^

i> . '^ ■•

—•9

70

59-5

y\. ■■ , I

, . .«.'

78

68

— 1

64

\

8141

10-357

10-302

— 6

50

59-8

13'6l3

73-459

roooo

^ ,

79

— 2
-6

HO

— 5

45
40
32
21
9

59-9

ma

8388

10-355

10392

81
—4

zero
10

60-7

14-015

—•7

21

Xi\o gorr

;g ^ijvf

e.Hm

822

28

. . ^ .

—3

31

—•5
—•5

32

^A::^v1i

raN^T.'

— -G

4o

—7

48

8635

10-427

10-423

—■fa

50

14-417

8045

10-428

10-424

83 '

52 T

54 y

599

14-433

'

....J

66(i5

J 0-427

10-4'27

83-1

56)

14^-465

-^ .* JA

(i> --jdj

T,<a!

ilH !

,60

60-1

60-3'

60-7

1

60 8

8R54

*

Tl>;>;tcv petit c >7/C

61

14-485

K 4

To

t^^ On the Conir action which takes place in Mercury

To recapitulate the foregoing Experiments-^
Observe,

^t A, mercury Is of the specific gravity 13'6l3 at the tern*
perature 50.

At 3j afcohol is of the specific gravity 'SHI at the tempera-
ture 50.

At C, silver is of the specific gravity 1 0*362 at the tempera^
ture 50.

At C and D there is error shown to exist in estimating the
..^specific gravity of bodies in the usual mode, without hav*

t (ing regard to a fixed point of temperaturcj at which the
medium chosen to compare other bodies with should be
estimated at rOOO j and without having regard to the ratio
of contraction in the body weighed, and the medium in
which it is weighed.

At E, a variation of contraction between mercury and al-
cohol expressed by 22 in weighing 5276 of mercury.

At F, the error of common practice noted at D is confirmed,
the increased loss of weight showing the contraction of
water to be greater than that of mercury of equal volume;
it is expressed by 4*7 in 150^ on the quantity 3024.

At G, mercury in its frozen state weighed by the hydro-
static balance lost 59*9 to 61 on the quantity of 100. For
the calculations from these facts, see L and the annexed
table. The mercurial thermometer felhbelow 270^ on the
scale below zero.

At H, silver, going down 1 50 degrees of Fahrenheit's scale,
contracts -j^-^^h, part of its dimensions, which is called its
visible contraction^

The silver at 117 above zero is 10*321

-^-^ 50 10-362

. r- 56 below zero 10*426

The increase of silver in its specific gravity is '0006114
each degree.

At I, the error of general practice observed at D and F is con-
firmed. A rule is given for finding the specific gravity of
the al^^ohol. When '8141 at 50 above zero it appears to be
•86G5 at bQ below zero.

At

ai low Temperatures , I S3

At T, the Increased specific gravity of alcohol each degree
is '0004934.

For the further variations of gravity see the annexed tdhle.
At K, a rule for finding the specific gravity of silver from
loss of weight at C^ and the specific gravity of alcohol att.
If silver at 50 above zero he 10'363, it will be
at 56 below zero 10*427.
At L, a rule is shown Ibr finding the specific gravity of mer-
cury .-—-At 200 above zero it is found lo be 12*407

50 J3-613

56 below »— 14'465

The increase each degree is *00804
. A comparison of C and G as it relates to alcohol ; and by
the rule at I it appears they accord in the number '8665,
the specific gravity at 56 below zero.
At M, the contraction of mercury in its solid state, sup-^
posed to be near twice that of silver, or '001 each degree,
because near the point of fluidity.

Alcoholof the specific gravity *8854 at 76 below zero.
Mercury in a solid form of the specific gravity 14*485
at 76 below zero.

The mode of calculating this is shown.
The increase of specific gravity of alcohol in each de-
gree not shown by the hydrostatic balance, when mercury
is weighed in it in a solid form, is '000061.
At N, rule for finding the increase of water of equal bulk
to that of mercury. It appears from F to be *0007^ each
degree.

Rule for finding the ratio of contraction of mercury,
alcohol, water, and silver, of equal volume ; mercury being
supposed 100.

A ratio of contraction also of water, mercury, alcohol,
ftnd silver; water being supposed 1*000.

Rule also given to find the ratio of contraction of alco»
Jiol, water^ silver, and jnercury, of equal weight.

XXIX, Essay

L ^54 ]

XXI)C. Essaf/upon M^ckinds-mghncrr'ail' Bij'M. CarnoT;

Member of the French Institute^ &C^&c,

! > . ) r ; t~ • ' J : ' '' [Cominued iroirt p: 1*5. J'^' ' ^ " ' ' * '

. X HE .sepond principle upoi> vvnicn-w;e purpose making
some observations, is ilic celebrated liw oV equilibrium of
Descartes. Tt tonics to this, that two powers in equilibrium
are always in reciprocal ratio tp their velocity, es-timated in
the direction of these forces, wlicn we svippose l^hat one of
the two comes to take it from tlic other in an infiiiitely small
degree ; so that a small movement arises from it.

But although this proposition be very beautiful, and we
generally regard it as the fundamental principle of equili-
brium in machines, it is nevertheless infinitely less general
iRa'ii that which has been quoted in the first plaqe ; becaj^se
it is applied solely to the case where tliere are only two
powers in the system : and besides, it is very easily deduced
ffeiifi-'what has been said upon the subject of the two weights
A and B, since v/e evidently approximate the one case to the
other by substituting, by means of pulleys, weights in
pface of the forces which we wish to value.

Moreover, it is to be remarked, that this principle does
not cjjpress the conditions of the eq^uilibrium between two
powers 'sb'cQihpletely as that \vhicK has teen quoted in the
first'place; 'for it only gives the accouiit of the quantities of
forccj cpmposino- equilibrium, at the place where the latter also
gtVe^, m some soh'^ ^thc account of'tjieir diVections ; — for ex-
ample, in the case of equilibrium between two weights, the
principle of Descartes solely teaches. that the weights should
te6 'in the reciprocal ratio to their, vertical velocities j but it
tlocs not indicate, like the first, that one of these bodies
should necessarily ascend, while the other descends. In
ftrder thai an ail^e, fcir instance, to the wheeh and cylinder
of which weights ar6 suspended by cords, should reniaiu
Tit ''eiqitili brill ni, it i;?^not sufficient that the weight applied
to the wheel be 16 thrii of thti cylFiider'as the radius of the
cylinder is to the radius of the wheel :— it must also hap-
pen that these weights tend to make the machine turn in
a contrary direction to each other ^ i. e, that thev are placed
io ui|[e rent sides with respect to the axis ^ else their efforts,
l'-'- ^ ■ % ^ *' being

Oil Machines in General, 1 55

being mutual, will put the machine in motion. It is
therefore evident that what renders the principle of Des-
cartes incomplete is, that by determining the reference of the
powers, as to their values or intensities, he does not express
that these powers should make opposite efforts, nor in what
consists this opposition of efforts: it is clear, in fact, that
for an equilibrium one of the forces must resist while the
other solicits : now, this is not what happens in the ca^e of
the' example of the axletrce; — But what is it in general that
distinguishes soliciting from resisting forces ? This in my
opinion has not yet been determined. We shall see in this
essay that the characteristic difference of these forces consists
in the angle they form with the directions of their velocities,
so that the one form always acute angles with their velocl-^
ties, while the others form obtuse ones with theirs.

Lastly. One fault with which we may reproach the princi-
ple of Descartes, as well as all those where we are discuss-
ing the small movement which would arise in the system if
the equilibrium was disturbed, is, that they do not indicate
the method of determining this small movement. Now, if
for this purpose we must have recourse to some new me-
chanical principle, the former is not sufficient ; and if we
can determine it by pure geometry, What is the method of
doing so ? This is what the principle does not say : and let
us not say that the proportion indicated by the principle al-
ways takes place whatever the movement is, provided it is
possible, i,e. compatible with the impenetrability of bodies;
for this would be an error: and we shall by and by show
that these movements are subjected to certain conditions, int
consequence of which I think it right to give them the nami
of geometrical movements.

We may make the same remark upon all the principles
upon v/hich we propose to consider a machine in' two
states infinitelv near each other; for, in order to detctiTirne
what arc those two states ; i. e. what movement the machine
should take in ordqr to pass frbn^ the 'one to the'odiifr,'\ve
inust either employ new mechatiical principles tonjiinctlv
with that proposed, which would render the latter insuffi-
cient ;

J 5$ On Machines in General,

eient; or else geometry is sufficient; and in this case it
is a defect in the principle, not to make known the geonij^^
trical conditions to which this movement is subjected.

VI. The two laws mentioned are confined to the case of
equilibrium. We pass easily from this case to that of the
movement by M. D'Alembert's principle in dynamics. But
we have found several others which are immediately applied
to the case of movement ] such as that of the preservation
of living powers under the shock of perfectly elastic bodies 5
which is so much the more gener^^l, as it extends even to the
case of the movement passing rapidly from one state to the
other: but it would seem that people have little dreamed of
the use that might be made of it in the theory of machines
properly so called. It is, however, evident, that this law
should have its analogy in the shock of hard bodies : and as we
generally take the latter to use it as a term of conjparison,
this principle, transferred to hard bodies with the modiii-
catipn which the difference of their nature requires, cannot
fail to be more useful than the preservation in question. We
shall show, in fact, that we may dedilce from it several
capital truths with the greatest facility, and particularly the
preservation of living powers in a system of hard bodies, the
movement of which changes by insensible degrees ; a prin-
ciple of well-known utility in the theory of machines. We
shall thereby see, at the same time, an intimate relation
between these two preservations of living powers; — we draw
from it also the principle of DeiScartes ; and even, by gene-
ralizing it, the law of equilibrium in machines with weights
above mentioned. This principle, in short, after having given
to it the extension of \vhich it is susceptible, appeared to us
to contain all the laws of equilibrium and of movement: and
>vp have not found a better for the basis of our theory.

VII. This essay will be dividc(J into two parts: In the
first we shall treat of the general principles of equilibrium
and of movement in machines; and in the second we shall
examine the properties of machines properly so caHed,
without ever stopping at any particular machine.

PART

On Machines in GoneraL 157

•PART FIRST.

General Pri?icipk'S^

When one body acts upon another, it is always imme-
diately, or by the agency of sISme intermediate body: This
intermediate body is generally what is called a machine : the
movement lost every instant by bodies applied to this ma-
chine is partly absorbed by the machitVeitseU*, and partly re-.
ceived by the other bodies in the system ; but as it may hap-
pen that the object of the question is simply to find the re-
ciprobal action of bodies applied to intermediate bodies,
without having arty occasion to know the effect of it upon
the intermediate body itself, it has been thought, in order
to simplify the question, to make an abstraction of the very
mass of this body* preserving to it on the other hand all the
other properties of matter. Hence the science of machines
has become in some measure an isolated branch of me-
chanics, in which it is required to consider the reciprocal
action of the different parts of a system of bodies ; among
which there are found things which, when deprived of the
inertness common to all parts of matter such as exists in na-
ture, have retained the name of machhies.

IX. This abstraction may simplify in certain particular
cases, where circumstances indicate those of bodies, the
mass of which it is convenient to neglect, in order more easily
to attain our object; but we conceive that the theory of ma-
chines in general has really become more complicated than
formerly : for this theory was once contained in that of the
movement of bodies, such as nature presents them to us ;
but at present we must consider at once two kinds of bodies;,
the one as they really exist, and' the other as deprived in part
of their natural properties. Now, it is clear, that the first of
these problems is a particular case of the latter; therefore the
latter is more complicated : further, although we easily suc-
ceed by similar hypotheses, in finding the laws of equili-
brium and of movement in each particular machine, such aj»
the lever, the axle, and the vice, there results an assemblacre
of facts, the connection of which is perceived with diffi-
culty, and solely by a kind of analogy ; which should ne-
cessarily

^8 On Caloric, and. the Heat evolved ^during ComtusfioH,

cessarilv happen, as often as we have recourse to the particu-
lar figure of each machiiie/ in order to demonstrate a pro-
perty which is coninjon to it- with all others. These
common properties being ^hqse whiych \^e;.have,,i;x;\5icy/ in
this essay, it is clear that v^^# shall only succeed in fuidingj
ihera by the abstraction of particular forms* Let i>s begin,-
lherxifore,J^y;simplifyin;g the. state of, ^he.q^^^^
ing to consider under one and the same system, bodies dij:-
fcring in. their natuiq. , Finally,, let us restore to niachines,
their visinertice, ^Jt^ ^\\\ j:)e^.ej\sy^ , ai^e^^,.^his,.^o ,|C^^
their mass in the result : we shall have the choice of doing
SQ- or not; and, in setting out, the soluli9i| of the probler^
T^ill be • eqvially. , geni^ral, at the same ;l|i|i)e,,tlxat it will be
simpler. .^a oi

[To be continued.]

XXX, On Caloric, and the Heat evolved during Comhisiion^^
By James, Scholes, Esq,, JMctnchester.

To Mr. rilloch. '^^"^

SIR, ,1, J- y,',

xIaving been induced to pay particular attention to co^ii-;
bustion for some time past, i have insensibly imbibed prin-
ciples diffcpent iVom the generally received theory, I very
coon began to suspect caloric as a compound substance, and
six months ago had recognised two fluids of electricity for
its component parts. The only demonstrative grounds I then
had for my ideas was the production of hght and heat, parti-
cularly the latter, and for the purpose of measuring the quanti ty
thereof I had an apparatus constructed. But when Mr. Davy's
recent experiments were noticed in your JNIagazine, 1 im-
n^ediately saw them as an additional support of my peculiar
principles, and prepared a lecture, which was delivered to a
Society in this town on the 29th of January, laying down
the whole system, as supported by facts deduced from elec-
tricity and the experiments of Mr. Davy, which I intended
to publish when more matured ; but on looking over the
monthly publications yesterday, I found a communication
in Mr. Nicholson's to a similar purport, which has induced

me

me to trouble y^u w^th mv cOjrr^i^uu}icayioi),^s^^^
imendcd. If you ^eem it wor.thy a place In yo4.ir'work, I;
shall feci obn2i;c(l iVy .the insertion.. Y()i) wilt sec that T come
to ^imilc^r conclivsjous to Mr. Gibbcs,. i[rpm a very diflfere-nt
investigation, and from different pncrnamena ; so ibat there
is no sameness in our productions. With respect to the me-.
rH'*6feacn (being somewhat diiTercnt), I can si'vihis, th^it I'
have 'candidly considered wh^t Mr. Gibbes ha3 adyarnct^d^,^.
but T shall not be disposed to admi^ withovU lurther inforii^ar-
ticfh one of his deductions: viz. that water js a sirnplesub-r

slahce, and the ba3e of both hydrogen nnd oxygen. i^^^'

■:■..' ':' T ' • - 1 ]•'' 111 • '■' ' t"^i"

J am^ sir, your obedient humble servant,^ ^ ■./,.'..

James Schole;s,

'Manchester,
March 4, 1808.

ON CALORIC, &(

CALORIC, 6CC.

^^. ^theory to be, just, ought to elucidate and exhibi^i.thtc;
cause of every phsenomena with which it is connected: if
it will .not do this, I shall even be inchned to believe that
its principles are erroneous, or at least very im perfect,,, ^Utis
an undoubted fact that there are many effects which the pre-
sent doctrine , of caloric does not pretend to explain at all ;
and again, , tbjsre, i jare raany others which it explains oiily
upon principles inexplicable in themselves. And if we take
a view, of the doctrine as applicable to combustion (which
is perhaps its forte)^ reflection cannot but produce dissatis-
faction with it. The present doctrine of combustion is
founded upon this basis : first, (which is undoubtedly just,)
that oxygen in every case unites with the combustible j se-
condly, that the caloric and light is produced by a dilTerence
in the capacity for heat of oxygen and the combustible, be-
fore and after combustion. But that this second part of the
doctrine is not so obvious, appears from the conjbustion of
gunpowder in vacuo, and many similar facts. Whcre^ ac-
cording to the present theory, caloric ought to be absorbed
instead of evolved, it is directly contrary to the system ; for
the products of combustion have considerably greater ca-
pacities, for caloric than the combustible and i^r.pporter of
combustion thcmsej\TS.

Other

160 On Calorkyand the Heat evolved during Comlustion,

Other phjcnotncna might be adduced to the same purport;
but this is the strongest proof, the best known, and suffi-
cient for my purpose. It will, I presume, be seen, that though,
one part of I^voisier*s doctrine is probably just, yet the
other is as likely to be erroneous ; and, from a retrospect
of the success of various fallacious theories, from their being
always established on s«[ihistical reasoning from experi-
menia! proof, which is as liable to deceive mankind now as
aforetime, we shall be justified in this conclusion; that though
Lavoisier's theory appears to coincide with experimental
proof, yet it may not be just, and that, failing to account for
many phaenomena with which it is connected, it is at best
imperfect, if not materially erroneous. It indeed accounts
for the emission of heat and light in common cases of com-
bustion plausiblv enough, it i^iust be admitted; — But where
is tliep-QofP Plausible reasoning is often sophistical ; and
I cannot by any means think we have sufficient grounds for
believing that the caloric and light of common combustions
are produced agreeably to this doctrine. It appears to me that
the evidence thereof is mt^rely presumptive, and in many in-
stances it is evident that the heat and light nmst be derived
from another source. That the state of combustible, &c., and
product of combustion, before and after the process, must
have material influence in the quantity of heat and light
ciyen out_, is not to be denied ; b*ut in rapid combustions I
am disposed to think the effect is not great in proportion to
the quantity generated by the process.

Since T perceived the deficiency of Lavoisier's theory, I
have been induced to pay particular attention to this subject.
Reflection soon taught me that oxygen and caloric must have
some remarkable relation to each other, as oxygen is the
only known supporter of combustion in nature : — what kind
of relation this can be, does not appear so ready to deter-
mine. Yet I am inclined to believe that it will be brought
to light before long, and that it will be discovered in the
new field of investigation opened by the" recent experiments
of Mr. Davy ; at least it is there I have looked for it. I
ju3t noted that there was a remarkable relation between oxy-
gpi and caloric, or rather between oxygen and the genera-
9 lion

On Catdrw, ami the Hm 'evolved during Coinlustion . l6l

tion of caloric by combustion. According to rny conccrptiotl
of the experiments of Mr. Davy, they show that combusti"-
hies on decombusiion jabsofb the electric fluid : and as we
know that no quantity of electric fluid is given out on com-
bustion, it appears probable that this will lead us to the dis-
covery of this relation between oxygen and combustion. We
cannot for a moment consider the electric fluid and caloric
as synonymous : we must therefore draw this Conclusion ;
That the electric fluid is probably instrumental in producing
the caloric of combustion, and that as it disappears therein,
it must disappear to form something else. The combustible
unites with oxygen, and we tind that a large quantity of ca*
loric appears as a large quantity of electric fluid disappears ; it
is therefore extremely probable that the electric fluid which
disappears, forms the caloric which is generated. This is the
result I infer from it ; and the manner in which I conceive
it is effected, I shall now lay down : viz. that there are two
electrical fluids in nature ; and that the peculiar relation ox^
ygen has to combustion consists in this — that oxygen is the
only substance with which one of them combines, and that
the other unites with the atoms of combustibles only ; — that
caloric is generated during combustion by the union of these
two fluids; consequently, that caloric is not a simple sub-
stance, but that its particles are composed of the two fluids
of electricity — this brings combustion to be a double de-
composition and combination, one of the products of which
is caloric ; that the electric fluids in some form or other are
blended with the atoms of matter, and like the atoms of
alkali and acids in salts veiling each other's properties;
that on the combination of oxygen with the atoms of the
combustible body, the electric fluids severally combined with
each, unite^ and form caloric, which is disengaged as gas
is set at liberty in other decompositions. As gas lighter than
atmospheric air is forced to rise up when at hbertv to do so,
so caloric, when disengaged, is by some power dispersed on
all sides.

It appears probable from a varrety of circurpstances, that it
is the vitreous fluid of electricity that unites with oxygen,
and the resinous with combustibles. If we note, therefore,

Vol, 30. No. 1 1^8. March 180^. L that

1 62 On Cal(X)ic, and the Heat evolved during Comhustion.

that gunpowder, containing one of these fluids in large
quantity in potash, and the other to a requisite extent in
sulphur, it will not be surprising, that gunpowder should
burn in vacuo, nor again that it should give out so much
heat and light on deflagration. These principles not
only account for every phajnomenon of combustion re-
lative to gunpowder, and by applying them to combustion
by acids, &c., likewise, but at the same time for the heat
emitted during combustion in air. Whereas, to reconcile
Lavoisier's system, wc are obliged to suppose an 'unnatural
chemical union of oxygen, different from its general pro-
perties, for which there is no other ground, than the con-
venience it is of, only to deceive ourselves, by regarding as
a property of nature, what is in reality only a property of
human imagination, and which, if persisted in, must effectu-
ally put a stop to this branch of science.

It must be obvious that these principles will in a most
simple and beautiful manner account for the light and heat
produced by electrical experiments and friction. To enter in-
to particulars would exceed the, limits of this paper. I shall
therefore conclude with a view of the process of revifica-
tion or decombustion. Suppose the body acted upon is iron ;
A quantity of resinous fluid unites with the metal, and the
oxygen of the oxide of iron is .separated in the process; it is
therefore as strictly a chemical union as that effected in com-
bustion. If we examine the process for therevification of ores,
we find it peculiarly adapted to produce this decomposition.
A layer of charcoal, then a layer of oxide, is alternately depo-
sited. The heat that is first produced by setting fire thereto^
carries off the oxygen of the charcoal in carbonic acid gas :
the carbon thus heated has an affinity for, and combines
with, oxygen. When, therefore, the oxygen of the charcoal
is exhausted, it unites with, and carries off in gas, the oxy-
gen of the ore, at the same time that the resinous electric
fluid of the carbon unites with the atoms of the metal.
Thus it is that fire both burns and unburns substances. The
fire acts no otherwise than by placing the particles of carbon
and oxide in a situation in which they have power to act on
each other: one part only of th« combustibility of the char-
coal

On the different apparent Magnitudes of the same Oljects, 1 63

coal supplies the heat requisite to this purpose, whilst the
other literally undergoes no con^bustion at all, but is trans-
ferred unaltered from the carlwn to the iron, or whatever
substance is employed; that is, part of the rei/inous fluid
which charcoal as a combustible contains., is expended in the
production of heat and gas, whilst the other part unites with
the iron (if such was employed) of the oxide, and renders
it combustible. The metal is rendered combustible at the
expense of the combustibility of the charcoal; and the reason
that the iron does not undergo combustion when rendered
combustible, is owing to the well-known chemical fact, that
substances alter in their propertiesby different combinations.
In this case we find that the resinous fluid (the principle of
combustibility) becomes more fixed in the fire by uniting
with the particles of iron, &c., than it was when united with
the particles of carbon. It appears, therefore, that the re-
sinous fluid (the^rinciple of combustibility) is more or less
fixed in the' fire, according to its combination with difl^erent
substances ; and that it is owing to this that to burn one
combustible one degree of heat is required, and another an-
other.

XXXI. On the Cause of the different apparent Magnitudes
of the same Objects seen under dfferent Circumstances,
By Ez. Walker, Esq.

To Mr, Tilloch,

SIR,

At the conclusion of a paper which was printed in the
Philosophical Magazine for last October, I mentioned that
the apparent magnitudes of all objects are variable, as well as
those of the sun and moon.

This, however, is not a new discovery, for M. le Cat
mentions it in several parts of his Physical Essay on the
Senses, printed in the year 1739. This philosopher says,
p. 234, " I looked through the glass of a casement, at a
very remote country-seat, which appeared to me sufficiently
large. I afterwards fixed my eyes on the glass itself; and it

L 2 seemed

1 6-1 On the dlffereJit apfmrent Mag?iitudes of the same Ohjccts,

seemed to me a great deal smaller than when T looked at it
directly. Since that time I have made repealled experiments
of this matter, and always found the same circumstances.*'
In another place he says :

^* I shall recount still something more extraordinary on
this variation of the magnitude of the visual angle, or of
the image of objects.

'S Last winter \ was in the country. In the night it froze
hard, and there fell a little snow. On going out of my
chamber in the morning, all objects appeared to me sensibly
smaller than they had done the evening before.

^*. Since I made this discovery, and have been guard-
ed against the rule of comparison, T plainly perceive that
a very illuminated object seems smaller, arvd an object
feebly supplied with light appears 4arger, The reason of this
is evident. A strong liirht puts the whole globe of the eye
on contracting itself, and a feeble one leaves it relaxed and
dilated.'*

This author is very correct in his observations ; but his
explanation is founded on a false theory. The true reason
is this : A strong light contracts the pupil oF the eye, in
which state it forms a small picture of an object upon the
retina; but in a weak one the pupil is ddated, and all ob-
jects then appear larger. This property of vision will,
I think, appear evident, from the following experiments.

It is diflicult to enlarge the pupil of the eye to any parti-
cular dimension, but it may be contracted at pleasure, by
means oF perforations made either in a thin plate or a slip
of paper.

Now, if an object be viewed through an -aperture, about
...Vjj. of an inch in diameter, it will appear much smaller
than to the naked eye, in consequence of the aperture of
the crystalline lens being contracted ; but if the perforation
be removed from "l>efore the eye, the object will instantly
appear increased in magnitude: and as no change can take
place in any part of the eye instautajiemisl?/, it is therefore
evident, that, the apparent magnitudes of all objects arc in-
creased by an increase in the aperture of the crystalline lens,
and consequently by an enlarged pupil.

4 The

On the Idenllty of Silcx and Oxygen. J 63

The same thing: may also be proved by looking at an
object th()ii(2,h perioralions of dilVerent dimensions 5 tor it
will appear snialier through a perforation of yJi-jj- of an inch,
than through one that is four times as large; and an object
viewed through a perforation as large as the pupil, appears of
the same magnit-ideas to the naked eye.

Whence it is manifest, that all tenestiial objects appear
larger to the naked eye in the mornings and evenings,
when the pupil is large, than at noon when the pupil is leis ;
and for the same reason they appear larger in winter than in
summer.

I ani; sir, your humble servant,

E. Walker.

Lynn,
March 18, 1808. -^

XXXII, On tlw Identity of Sllex and Oxygen. By Mr,
Hume, of Long- Acre, London, '

7b Mr, Tilloch,

SIR,

JL o inculcate any science with success, there is nothing so
essential as a simple and perspicuous display of its lirst prin-
ciples ; and if there be any department in j)hil()Sophy to
which this observation is uiore peculiarly applicable, it is
certainly the study of chemistry, than which there is, pro-
bably, none more useful to man.

The present period is, of all others, the most opportune
for an improvement in chemical theory, as, from the very
brilliant discoveries of Professor Davy, it is ob-.''ous that a
most material revolution is now dawning upon tlic modern
system of chemistry, anfl, possibly, an entirely new struc-
ture must eventually prevail. 1 now allude to the word
oxygen particularly, which, in its present limited sense,
stands as a solecism in language, and a mere absurdity in
the nomenclature of the day, since it has been lately proved
to be at once the principle of acidity and likewise that of
alkalescence,

Jn all modern authors, the classification of simple and
L 3 eknien-

t66 On the identity of Silex and Oxygen,

elementary bodies is, I presume, too diffuse, in respect
to the number of subdivisions ; and many of the titles
employed might, with propriety, be expunged. But,
though there are many other imperfections in chemical
arrangement that require reform, T mean on this occasion
to confine the following observations to one article only 5
and shall endeavour to prove that, in this instance at least,
we should revise the list of simple substances, aS far as re^
gards silex; which is still continued, I think, with great
impropriety, to rank as a species of earth.

To include in any one genus both silex and the other
earths, as they are now called, seems extremely improper
and palpnbly erroneous; nor can this classification be sup-
ported by any reasonable argument whatever. The defini-
tions given frpm time to time, to distinguish an earth .from
any other elementary body, have never been sufficiently ex-
plicit, for they do not precisely exclude the alkalis : they
make a useless division under the name of alkaline earths;
and, as salifiable bases, an earth, a metal, an alkali, and
silex, may be said to range as fotir distinct species of the same
genus. -. t

All earths are declared to be salifiable bases, snd this I
take to be the most essential clause in every definition; for,
generally speaking, the earths have a ready affinity for every
acid, even from the weakest, particularly the carbonic acid,
to the most powerful that exists. Indeed, as far as concerns
the combination with carbonic acid, with which the earths
form nearly insoluble compounds, this peculiar property
alone might have served to distinguish an earth from an al-
kali. Here, however, the principal force of the definition
fails, the exception to silex is decisive; there is nocarbonate
of silex; no nitrate, no sulphate, nor, in short, any other
salt, in which the acid is saturated by this simple element :
neither art nor nature ever produced a perfect neutro-saline
compound, in which silex could fairly be considered as a
real and independent base.

To constitute a true salt, we know, there must not he less
than one acid and one base, reciprocally saturating each
other; and when the nmnber of either exceeds, and the

salt

On the Identity of Silcx and Oxygen; \^

salt is not a binary compound, we may then fairly suspect
an imperfection ; for, one of the elements at least is fre-
quently in the state of mere suspension, and not in chemical
union with either of the other ingredients.

There are, indeed, numberless examples of such salts,
and, I am ready to allow, some in which silex is found,
whether as a mere contingency or otherwise ; but it never
exists as a perfect base, that is, possessing the capability of
saturating the whole, or any part of the acid in sivch com-
positions.

If silex be, what I have long considered it, not only dis*
similar to every elementary ponderable material besides,
especially in generic characters, but, also, so vastly superior
in its importance and bulk, as to leave no room for compa-
rison ; surely it ought then to be instantly removed, and no
longer suffered to remain in the list of earths, but should be
placed in the most prominent station in the arrangement
of elements. Such is its consequence, that nothing in na-
ture is so predominant or so universally disseminated ; no
compound solid substance of any magnitude is exempt from
it, but contains always some, if not a very large portion of
this insinuating, and as I conjecture, most essential of all
terrestrial matter.

All organised bodies either contain silex, or, what I shall
consider as a modification, oxygen. If there be any excep-
tions to this conclusion, they are so few and of such trivial
import, that when they do occur they should be rated as
anomalies ; and it may happen, that the apparent absence of
silex or oxygen is rather to be attributed to our want of
means, and the imperfection of science to discover it.

In a geological view of this subject, where can we turn
our eyes or employ our thoughts, without meeting this grand
and multifarious cement' — this bond of aggregation, that fixes
the solidity of all tangible nature ? The very outlines of our
planet are traced out with it; and all primitive matter, from
the most stupendous mountani or rage^ed precipice to the
deepest cavern, even to the centre of gravitation, we arc
warranted to say, is replete with silcx. If we contemplate
the nature, volume, and importance of this, and then rccol-

L 4 lect

l!68 Oa the Identitij of Silex and Oxygen,

hct the insignificance of zircon, glucinc, anJ indeed the
whole of the species of earths, none of which exists without
an association of silex — all comparison vanishes, there is
no estimate ; these are as the mere spots to the brightest of

luminaries, and therefore, in all systematic classification,
should be separately arranged.

Where then ought silex to be placed in the arrangement
of simple elements? — should it link with any other ponder-
able body as a species of the same genus, or preserve a
station to itself? Were I asked for an answer to such a
question, I would say — that seeing^ nothing to which it has
the slightest resemblance but oxygen-gas, of which I con-
ceive it to be the true base, here I would not only assign its
proper rank, but give it alao a precedence to all other elemen-
tary matters that had resisted decomposition.

It is hardly necessary for me now to add, that I do not
consider o^-ygen in the state o'i gas to be a simple body ; for
whatever is susceptible of spontaneoiis change should al-
ways be deemed a compound of at least two elementary siib-
^jtances. If one instance of this can be adduced, we may
naturally infer that others will be found; and, fortunately
for my present purpose, a most appropriate example has
lately occurred, which confirms this conclusion : I allude to
the experiments of Messrs. Allen and Pepys*, upon carbon
and carbonic acid, which appear to have been conducted
with unconniion precision and genius, Froni these gentle-
men we learn, that oxygen-gas is subject to spontaneous
change, pr, as they very properly express it, a deterioration;
/ind that this will happen, though the gas be of the purest
kind, that obtained from oxy-muriale of potash ; and even
when seciircd in glass vessels with glass-stoppers,

paving assumed silex and the base of oxygen gas to be
synonymous and simple bodies, I shall now proceed, as far as
my humble pretensions and Jcnowledge of this subject wiU
permit, tqsubstantiate this position, by ofiering a few only of
the numberless lacts, which seem to confirm this identity.
It is a task, I confess, I have imposed upon myself; foi;',
^laving nearly three years ago permitted my opinion to he

*. Fljiioaopliical Transactions iS07.

pub-!

On tJie Identity of Silex and Oxygen. 1 69

published, though unaccompanied with any explanation or
proof, and as the work * has now arrived at 'us second edi-
tion, it becomes my duty to absolve its author from all re-
sponsibility 'y and, rather than any blame should attach to
him, avow myself as the only person, who is accountable for
promulgating tenets, which to many philosophers must
have appeared to be visionary.

It is scarcely necessary to explain what Is here meant by
the word silex. But, that I may be clearly understood, I shall
define it to be, the very pure part of rock-crystal, and that
which constitutes by far the greatest portion of all sand, flint,
gravel, and other well described rocks, stones, and minerals :
a substance common in every spot of the globe, in every
zowQ^ anjd in every climate; and an article so obvious and
familiar to the meanest capacity, that any further descrip-
tion would be superfluous, I shall just observe, that 'in
rock-crystal, in quartz, and in hot-springs, silex is nearly in
its pure and primitive stale of perfection.

There is no subject, in which analogical reasoning is more
admissible or more conducive to arrive at the truth, than the
one before us : and indeed, whenever the discussion has for
its object the works of nature, as in chemistry and its sister-
science, geology, I do not see it possible how this mode of
argument can be wciravoided. It was analogy that led the
penetrating mind of a Newton to some of the most brilliant
of his discoveries ; and it was the same faithful guide that
conducted this immortal philosopher to predict some of the
most important truths, which have since been so completely
established by the experiments of his successors. The com-
'bustible nature of the diamond, and likewise that of water,
are among these examples : they are facts that will for ever
bear testimony to the great advantages that may be derived
from this nicthod of searching into the secrets of Nature*s
unerring works^ and the laws which these obey.

Now, to apply this mode of reasoning to the present
object of research, let us consider this our sublunary
world under its three grand divisions. The first, is the at-
piosphere, which surrounds and compresses the whole of
the others; an4 this may be called iht^ aerijorrn division of

* " Clicii^ical Cjitechisnx."

nature

1 70 On the Identity of Silex and Oxygen,

nature. Here, it Is allowed, the principal element x^ ox-
ygen ; but it is now in the gaseous state, that is, it is sa-
lurated with caloric. I have said, the principal element,
because it is the most important of all others :— it is tht^
matrix of fire, it is the pabulum of life ; in short, such is
its consequence and value to the very being of all orcjanized
matters, whether in the animal, vegetable, or mineral king-
■dom, that surely some more appropriate name might have
been devised, than what it now bears. Though it is a di-
gression, and remote from my plan, I shall take the liberty
to hint, that i^erely by modifying, that is in soirie measure
reversing, the theory which first employed the word phlo-
ghtoni both this word and the theory itself might with thfe
greatest propriety be revived: and the word phlogiston,
even in the theory of the present day, would more aptly suit
our comprehension of all the properties of pure air, than
that oi oxygen, which implies merely the generator of vine-
gar or sourness, a derivation of all others the most puny and
incomplete.

The second grand division, is the ocean, sea, or water,
which we may name the aqueous portion of the whole.
Here we again recognise our oxygen, not only as the princi-
pal ingredient in magnitude, being about four- fifths of the
whole, but in all other respects claiming our first atten-
tion. In this water, the oxygen is further concentrated,
having lost a part of the caloric which it possessed in the
gaseous form, or in the atmospheric state ; so that, in this
case, we may tiow conceive it to be, in regard to density,
midway between earth and a:r; and that, by an abstraction
of more of its caloric, it must approach nearer to a state of
solidity.

•V If oxygen, therefore, constitutes such a prominent and
^hiking feature in two-thirds of the works of the Au-
thor x>f all creation— -which, in these cases, is a truth that
admits of no controversy. Why, it may be aptly demanded,
should it not, also, form the most conspicuous ingredient in
the other third, that is, the solid or real terrestrial portion of
this material world ? Analogy and the general complexion
of all the phasnonjcna of nature seem to answer in the
afiirmative, and, I think, will aflord &ome of the oipst legiti-
1 piate

On the Tullic Utility of Medical Instituthm. 171

mate proofs, in confirmation of the doctrine I have as-
sumed, the identity of silex and oxygen.

This theory seems to be supported by such a mass of evi-
dence, that it is diffieuh to say where we should begin.
GeoJogy is, however, a source so prolific, that every spot of
the globe teems with examples : There is not a rock, frorti
the most huge and congregated lumps of matter, that rendet
the face of nature at otice awful and magnificent, tb the rnoflt
thfling pebble ; nor ii there a morsel of any mineral com-
()ound, whether Jt be the brilliant gem or the most unfruitful
and degraded soil, where, if there bfe an earth, a metal, an
alkali, or any other salifiable or oxiuable element, the
saturation is not always due either to silex alone or to some
acid^ that is, consequently, something -conlainihg oxygen.
Such seems to be their equivalence, that when silex is ab^
sent some acid must prevail ; and it neither be found in the
ass6ciation, then the earth, metal or alkali, whether potash
or soda, puts on its obvious and peculiar character, such as
taste, solubility, density, and the other generic qualities
proper to each species '■^■

^ After silcx, there is no substance so plentiful as lime, but
this is never found pure; it is either saturated with an acid,
c>f dwindles into a tasteless inert state of aggregation
with other bodies, where it is subdued and locked up by
silex ; so that, there is not a vestige remaining of its primi-
tive qualities, especially those of taste and solubility.

That lime, even when pure, is a compound, there is little
room to doubt ; and that carbonate of lime, or chalk, is pro-
duced at the expense, and through the means, of the degra-
dation of silex, may probably (Reserve a candid and minutfe

inquiry.

[To be continued.] \

XXXIII On the Public UtiUhj of Medical Listilufions for
the Benefit of the Diseased Poor,

To Mr, TillocJu

SIR,

JL HE foundation and support of the many medical esta-
blishments for the benefit of the diseased poor, not only iu

the

1 72 On the Public Utility of Medical Institutions,

the metropolis bul ibroughout the kingdom, reflects the
highest honour on the national character. This has long
been acknowledged; and it could not fail to be highly grati-
fying to the public, who contribute so largely towards their
support, to have a statement published annually of the re-
ceipts and disbursements of each institution, vvith an account
of the benefits derived from them to the diseased poor, f
do not think this desirable object is sufficiently attained, by
the committees of a few charities circulating a report of
the finances of the institutions over which tliey preside,
among their own members or subscribers The object in
view would, I conceive, be best attained by means of sonve
periodical work, where the reports should be recorded and
referred to ; by which the advatitages of each charity to the
diseased poar \\ou\(\hQ. made evident; and a liberal public
would in a few years be enabled to form a correct judg-
ment as to what kind of charitable institutions was best
entitled to their munificence.

.The frequent, and in some instances successful, attempts
to depreciate the utility of dispensaries, have led to these re-
marks ; and when it is known that for an annual sum of
2,OOOZ, upwards of 9,000 of the diseased poor are an-
HUiilly admitted and attended in three of these institutions
ill London, (those persons being visited at their own houses
who are too ill to go to ihe charity,) it must be confessed
th2L\ dispensaries d^^t son\t\\!h'A\ more \\v3A\ '''so many hot-
beds calculated to rear and cherish their plants* for the
public service"

It is not my intention at present to analyse the motives
which probably gave rise to the above and many similar
observations, it being sufficient to record the fact; neither do
I mean to advance any thing that should militate in the
least against the many truly valuable public hospitals; but
only to observe, that the great l3E^'EFlT derived by each ia-
dividnal inhabitant of these asylums prevents its being ex-
tended to the numbers requiring aid, their establishnient not
being of sufficient magnitude to lodge and feed all the
4is<:a:>ed poor : nor would it be sound policy to extend their
* The rn?<lical ofiicers.

benefits

On the consiltuenl Principles of Potash, 173

benefits so far; it being proved by the above statement, that'
0,000 patients are attended annually in three dispensaries,
a sum not more than adequate to the maintenance of 470
in an hospital. . , ^

Greville street, Hatton Garden, JoHN TaUNTON-

Ffebruary24, 1808.

XXXIV. On the constituent Principles of Potash, By
Mark Taerg, Esq, of Beeston, near Shrewslury,

To Mr, Tilloch. ^, ,^,

SIR, March 21.

J-N a letter I sent you, dated September 1806*. I suggested,
the probability that oxygen was an ingredient in the compo- '
sition of potass. This has b^^en now confirmed by Mr.
Davy : and although I was not right as to the quantity, I
think J may claim some little merit. The rest, I said, was
lime and though here I must have been mistaken as to the
quantity, it still remains to be disproved that it does not
enter into the composition of potass. May not lime be an
oxide of the same metal as potass ; or may not that metal
united \Vith other substances form lime? I think the sub-
ject worthy of investigation : and unless some one abler
than myself takes it up, I shall trouble you with an account
of the result of some experiments which I am about to make

' Mark Taerg.

XXXV. On the best Aleans for preventing the fatal Cori"
sequences that so frequently occur from the Dresses of
Females and Children taking fire.

To Mr. Tilloch.

SIR,

JNoTHiNG can be more distressing to human minds than
the accounts sofrequenily given in our public prints, of wo-
men and children being burn-t to death by the accident of

* .See Phil. Maj. vol. xiv. p. 358.

their

17^ Means for preventing the fatal CoitsequenCes

their clothes taking fire. Desirous of ascertaining how far
persons in that horrible situation are likely lo be relieved
by the judgment and exertions of those who might casually
be near them, I have for some time past made a point of
turning the' conversation to this subject, among friends, ac-
quaintance, and strangers j and regularly inquired of the
men, how they would act, supposing themselves itte a tcte
with aiady whose clothes had caught fire. I found them
generally slow to reply ; — that not one of them appeared at
all prepared against such an event ^ and that their resources
were few and shockingly defective. Some thought they
iTHist be guided by circumstances : forgetting that coolness
and decision, which are essentially requisite in such trying
predicaments, do not attend all men in the moment of
alarm and danger. Others would pull off their coat to put
over the flames and smother them : — hut the greater num-
ber were for rolling her in a carpet. None ever mentioned
any thing preferable : This last expedient appeared to be
thought »the best that could be devised — the ne plus ultra,-^'
It had not however occurred to them that the apartment
might not be furnished with a carpet. This sad experience
leads me to fear, that whoever will take the trnuble to
repeat the experiment among his fiiends and acquaintance,
will not obtain any more satisfactory results.

Although the insufficiency of these means must on a mo-
ment's retiection be obvious to the humblest capacity, still a
kind of infatuation has made them be persevered in without
further thoughj: — No rational plan is formed — All is in fact
left to chance; the consequence of which must necessarily
prove fatal in nine instances out often.

In circumstances of this nature, relief itself would be ex-
treme torture, unless it be prompt : not an instant must be
lost : but while chairs, tables, and other incumbrances are to
be removed off the carpet ; and before the sufferer can be laid
down in it, or that it can be drawn over her, the flames will
make rapid progress ; and until she is entirely wrapped up in
it, the flames are fanned and urged by the operation, which
moreover takes up too much time.

Considering the multitude of valuable lives which have

perished

arising from the Dresses of Females taking fire . 175

perished in this miserable way — many of which it is proba-
ble might have been saved, had better means been employed
— and that families of every rank, without exception, are
equally liable to this sudden and dreadful visitatipn, it might
naturally be expected that something more adequate, to
mitigate its effects, would ere now have been made known
and adopted.

In the belief that nothing of the kind has yet been done,
I think it a duty incumbent on me to suggest, through
your medium, what will be found an infallible method in-
stantly to extinguish the flames which have caught a female's
dress — which is as follows : —

The hands of any assistant must be passed under all the
clothes, to the sufferer's shift ; and then the whole clothes
are to be raised up all together, ai>d closed above her head.
The flames will thus most certainly be extinguished. This
may be done in five or six seconds — in the time that a per-
son can stoop to the ground and rise up again,— and no
ether method can he so ready, expeditious, and effectuaU

The sufferer will facilitate the business by folding her arms
close before her. Should it happen that no pCiSon is at
hand to assist the sufferer, if she has presence of mind, she
may in most cases relieve herself by throwing her clothes
over her head and rolling or laying upon them.

This method was always communicated to those with
whom I conversed on this subject, who all expressed the
greatest satisfaction at the probability, and confidence it^
gave them, of being thereby, better than hitherto, enabled
to rescue fellow-creatures from agonizing premature death ;
and esteemed it a valuable addition to their small stock of
rxpedients. '"*

The extending this communication to your readers may
be productive of the happiest consequences to them and the
community at large, and materially reduc<; the list of human
afflictions. I am, sir,

your very humble servant,

March 22, ises. E. V,

XXXVI. Ui^

t no ]

XXXVI. Letter from ^/r 11. C. Englefilld, respecting
his Mduntain Barometer.

To Mr, Tillock.

SIR,

In a note at the bottom of page 1 9 of your last number, I
preferred having the lower part of the tube only a twentieth
of an inch in the bore, something on the principle of the
marine barometer. Upon a mare minute investigation, I
do not find that this would answer the purpose so well as I
then thought, nor is it so good as the simple tube. J there-
fore beg your insertion of this for the information of your
numerous readers. I am, sir, &c.

H. C. Englefield.

March 21, 1808.

XXXVIT. Report of Surgical Cases in the City and Fins-
bury Dispensaries, for October 1807; loiih some Remarks
on the Dissection of the Brain of a Person uho died in'
sane. By John Taunton, Esq,

An the month of October there were admitted on the books
of the City and Finsbury Dispensaries 21 1 surgical patients.

Cured or relieved — 193

Died — — 2

Under cure — 1 0

211

Since which time there have been admitted 969.

A few days since, I was requested to examine the head of
a person who bad been insane for some months preceding
death, which took place suddenly, letat. about 35.

The general appearance of the body, which was robust,
indicated a high degree of health and strength.

On removing the upper part of the scull, the dura mater
formed a considerable projection over the posterior and su-
perior part of the left hemisphere of the cerebrum, near the
course of the longitudinal sinus. On cutting through the ex-
ternal

Report upon a Memoir on the Nitrous Ether, 177

ternal lamina of that membrane^ a granulated substance ap-
peared, like a great number of small tumours adhering to the
dura rtiater, tunica arachnoidea, pia mater, and even to the
cortical substance of the brain, aboui two inches in length,
half an inch in breadth, and nearly half an inch thick. The
other part of the dura mater was of the natural appearance.

The arachnoid membrane was more opake than usual,
arising partly from lymph deposited on its Under surface,
and partly from an effusion of a serous fluid between that
membrane and the pia mater.

The cerebrum and cerebellum appeared natural, but the
lateral ventricles contained about four ounces of a straw-co-
loured fluid ; the surface of these cavities was every where
covered with a layer of coagulable lymph, having that aspe-
rated appearance peculiar to recent inflammation. Many
small hydatids were attached to different parts of the cho-
roid plexus.

Is it not highly probable that the symptoms of insanity
took place in consequence of the pressure produced by the
tumour upon the brain? and also that the inflammation
was excited by the same cause? If these positions be ad-
mitted. Would not the antiphlogistic mode of treatment,
carried to an extent agreeable to the apparent stamina and
strength of body, which have been rarely exceeded, have
produced a more favourable termination ?

Since I exainined this case, I have heard from the medi-
cal gentlemen who dissected the body of Simmons, the
murderer, that half an ounce of water was found in the la-
teral ventricles of the head. I believe it was never doubted
that this unhappy person laboured under a brutal and fero-
cious insanity from his infancy.

XXXVIII. Report upon a Memoir read at the French Insti-
tute fly M, Thenard, tip07i the Nitrous Ether. By Messrs.

GUYTON, VAUaUELIN, and BbRT HO LLET*.

iJiFFERENT kinds of ether have been formed by the action
of some acids upon alcohol. Volatility, inflammability,

* Ann. de Chimie^ torn. Ixi. p. 2 ^.

Vol. 30. No, 1 1 8. March 1 808. M and

178 Report upon a Memoir on the Nitrons FAhef,-

and a specific smell, give to ethers a decided character,
which does not admit of their being confounded with other
substances. We know but imperfectly, however, the differ-
ences which distinguish them from each other; aiMl in par-
ticular, we have but an imperfect theory upon their produc-
tion. Messrs. Fourcroy and Vauquelin have indeed thrown
a great deal of light upon the production of the sulphuric
ether ; but their explanation cannot be extended to that of
some other ethers. It was therefore important to resume
the subject, in order to treat it in a general manner. This is
whatM. Thenard undertook; — In the first memoir present-
ed to the Institute, he treats of the nitric ether. He will
afterwards proceed to the others ; and will examine why
some acids have the property of producing ethers, while
others are deprived of it.

M. Thenard first brings under review the processes re-
commended by chemists for producing the nitric ether.
These are very discordant, and only have for their object the
etherized liquof, which we may obtain without any analysis
©f the gaseous products, nor any consideration of the cir-
cumstances of the operation, unless we except the Dutch
chemists, in a memoir which has particularly occupied M*
Thenard*s attention, at the end of his own,

M. Thenard began by distilling a mixture of equal weight
of alcohol and nitric acid, both being of a determinate con-
centration, in an apparatus proper for separating the liquid
products from the gaseous ; a slight heat is sufficient, and
even the action becomes so brisk that it is soon necessary
to check it. He afterwards examined the residue of the
retort, the liquid produce, and the gases. The residue wa;?
composed of nitrous acid, acetic acid, alcohol, water, and a
little of a matter the nature of which is not determined,
but which chars easily. The proportions of these sub-
stances are established by ingenious and precise means. But
we are obliged to pass over the details necessary for a cfear
idea of the numerous operations M. Thenard's experiments
require ; — if we push the distillation to dryness, the viscous
residue contains oxalic acid, and probably malic acid.

The liquor distilled, which has been regarded in laboratories

as

Report ilpoH a Memoir on the Nitrons Ether, 1 79

as the nitric ether, is found to be composed of water, ni-
trous acid, acetic acid, ether, and probably alcohol.

The gaseous product has in particular required much pa-
tience and dexterity^ in order to separate it into different ele^
ments ; to assign to each of these elements the properties
which belong to it ; and to explain the differences which
result from the circumstances in which this gas is placed.
It was composed of the nitrous gas, azote, oxide of azote,
nitrous acid, carbonic acid, and of etherized gas, which it
was particularly necessary to detach from the rest, in order
to examine its properties. The author was led by these pre-
liminary experiments to the following^ process, in order to
separate the pure ether^ and to examine it, whether in its
liquid or gaseous state.

He put into a retort five hectogrammes of alcohol> and
as much nitric acid. To the retort were successively adapted^
by means of glass tubes, five long flasks half-filled with wa-
ter saturated with muriate of soda. The last had a tube>
which opened under a bell-glass, filled and destined to
collect the gaseous part. All the flasks were surrounded
with a mixture of pounded glass and sea-salt, which was
stirred from time to time. The operation began by means
of a little fire; but it soon became necessary to extinguish it,
and even to cool the retort.

The liquid remaining in the retort was analogous to that
in the first-mentioned experiment.

There was found upon the surface in all the flasks a yel-
lowish liquid, and which, when collected, weighed 255
grammes. That contained in the first flask was a mixture
of alcohol, ether, acetic acid, and nitrous acid ; that con-
tained in the other flasks was nitric ether, free from alcohol.
In this state the nitric ether possesses a strong smell ; it is
specifically lighter than water, and heavier than alcohol ; it
is dissolved in the latter in any proportion, but it requires
nearly <18 parts of water to dissolve it, and yet the latter dis-
solves it partly as we subsequently find. It presents in a
strong degree the^roperties of combustible bodies. Never-
theless, this ether strongly reddens turnsole tincture; and it
owes this property to a little nitrous acid and acetic acid,

Ms which

ISO Report upon a Memoir on the Nitrous Ether »

which it retains, and which we may separate from it by
means of Hme.

The volatiHty of the ether thus prepared is such, ihat the
tension it indicates is 0-73 metres, while that of the best
sulphuric ether in the same circumstances is no more than
0*46 metres, at 21° in the centigrade thermometer, and 0.*76'
metres of atmospheric pressure. We see, therefore, that
at this temperature and pressure it i5 at the limits of its ex-
istence in th(5 liquid state.

But if we can deprive the nitric ether of its acidity by
means of lime, it hastens to become acid again, whether we
distil it, leave it in contact with the air, or keep it in welt
stopped battles. This formation of acid also takes place
when we treat ether with water, particularly if the tempe-
rature is from 25° to 30° of Reaumur. The author explains-
the formation of the acid, by the reciprocal action of the
principles which constitute ether, and which are there feebly
retained by combination.

M. Thenard afterwards proceeds to the decomposition of
the nitric ether by heat, and he analyses the gases which
proceed from it, founding his calculations upon the most
exact data hitherto found : he obtains as a result, that 100^
Dirts of nitric acid is composed (laying aside fractions) of
A^ote — 16

Carbon> — 39

Oxygen — 34

^ Hydrogen — • J);

From this^ he concludes what passes in the reciprocal ac-
tion of alcohol and nitric acid. The oxygen of this acid ia
combined with a great part of the hydrogen of the alcohol, and
with a very small quantity of its carbon. From this there
results, 1st, A great deal of water and gaseous oxide of
azote, a litile caibonic acid, and a little nitrous gas and ni-
trous acid; 2dly,The separation of a small quantity of azote>
and the formation of a great deal of nitric ether, by the
combination of a sufficiently large quantity of the two prin-
ciples of the nitric acid with the de-hydrogenated and
slightly decarbonized alcohol ; 3dly, The formation of a
little acetic acid, and a small quantity of a substance which

is-

Report upon a Memoir on the Nitrous Elfier, 181

is easily carbonized by a combination of one part of hy<lro-
gen, carbon, and oxygen.

Supported by these results, M. Thenard discusses the pro-
cesses which have been pubhshed for obtaining the nitric
ether ; and he shows that some of them are dangerous in the
execution ; and that the whole furnish but a part of the ether
which may be obtained from the same quantity of ingre-
dients, and only yield liquors more or less compound, in which
the nitric ether, the name they go by, in reality forms but a
part.

The Dutch chemists have made some interesting inquiries
respecting the nitric ether, or rather upon the gas obtained
by the action of the nitric acid upon alcohol. They have,
however, resorted to an insufficitnt hypothesis, in order to
explain the curious facts they communicate. 1st, They have
regarded the gas in question as a combination of nitrous gas
and ether, while it is composed of gaseous ether, nitrous
gas, nitrous acid, azotic gas, gaseous oxide of azot, carbo-
nic acid, acetic acid, and, in short, of all substances suscepti-
ble of assuming 4he gaseous form in the variable circum-
stances in which they exist. 2dly, They have supposed that
ether was an identical substance ; so that they have entirely
neglected lo analyse the nitric ether, and establish its distin-
guishing characters. 3dly, A consequence of this opinion js,
that they have attributed to a pre-existing nitrous gas, phae-
nomena which are owing to the decomposition of the ni-
tric ether.

After having discussed the opinions and experiments of
the Dutch chemists, M. Thenard concludes his memoir,
by remarking that he has only considered the products and
phaenomena obtained in a given proportion, and in determi-
nate circumstances ; the effects will be different under other
conditions which he purposes to introduce : but he has al-
ready convinced himself, that those he has used are most fa-
vourable to the production of the nitric ether.

M. Thenard's memoir contains a great number of new
facts, and very delicate analyses. He determines the nature
of a substance} very remarkable in its properties, and yet
he only presents it as the 'beginning of a laborious work

M 3 only

183 Royal Sociehj» — Society of Jntiqiiaries,

upon ethers, pf which we pledge ourselves to give an ac-
count.

The Institute has approved of the present report, and
adopted its conclusions.

XXXIXt Proceedings of Learned Societies,

ROYAL SOCIETY.

JVIarch 3, 10, and 17, (A.Marsden, esq., vice-president, in
the chair,) Dr. Richardson's geological observations on the
North of Ireland vvere read. The Doctor confined himself to
what he conceived to be peculiar facts, or rather the local
features of the basaltic mountains in the counties of An-
frim and Derry, dividing the strata which appear in some of
the most perfect columnar basaltes into sixteen divisions,
of different depths. He traced the appearance and disap-
pearance, in several mountauious places, of those ridges
called whin-dikes, and thence inferred that the whole basal-
tic district must have originally been one continuous mass,
and that the separations or divisions, which now form ex-
tensive plains and valleys of several miles extent, must have
been formed by some power in nature with which we are at
present unacquainted. Dr. Richardson thinks, neither the
Neptunian nor Volcanic theory sufficient to explain the v^?
ried phaenomena of nature, which must be left to future ages
and discoveries.

Feb. 24. — The reading of observations on the late comet,
by Dr. Herschel, commenced. The Doctor defined the
terms of head, nucleus, disk, coma, and tail ; and directed
his experiments to ascertain the real dimensions of its nu-
cleus and disk. These he performed by comparisons with
wax-balls viewed in his ten feet reflector, the results of which
he applied to the apparerit magnitude of the comet's disk,

SOCIETY OF ANTiaUARItS.

Mr. Lysons laid before this society an account and draw-
ings of a mosaic pavement found by him at Frampton, Dor-
setshire, in 1 796. This was ope of the largest mosaic pave-
ments found in modern times 5 it was 3Q f^et Ipug, and 20

broad,

Geological Society, 163

broad, <livided into several compartments, with figures of the
heathen gods and other emblems. It could not be ascertained
to v/hat this mosaic had been appropriated, only that it was
surrounded by a hard clay floor,

GEOLOGICAL SOCIETY.

On the 13th of November last, a society was formed in
London under the above title, of which we have avoided
giving any notice, till we could announce it^ objects and
constitution.

Of its Objects. — This society is instituted for the purpose
of making geologists acquainted with each other; of stimu-
lating their zeal; of inducing them to adopt one nomencla-
ture; of facilitating the communication of new facts; and
of contributing to the advancement of geological science,
more particularly as connected with the mineral history of
the British Isles.

': of its Constitution. — ^The geological society shall consist
of a patron, president, two vice-presidents, treasurer, secre-
tary, ordinary and honorary members. The president,
vice-presidents, treasurer, and secretary, shall be annually
elected by ballot..

Of its Members. — T. Members shall be chosen by ballot,
the election to be unanimous. — II. Any person desirous of
becoming a member, may communicate his wish through
the secretary to the society ; and, without being proposed or
recom'Tjended in any other manner, shall be balloted for at
the next meeting. — III. Any member desirous of proposing
aji honorary member, shall communicate his wish through
the secretary to the society. The person so proposed shall
be balloted for at the next meeting : if elected, tiie name
and recommendation of the member proposing shall be read
and noted in the minutes ; if rejected, they shall be sup-
pressed.

Of its Meetings. — I. The society shall dine together on the
first Friday of every month, from November to June inclu-
sive, at five o'clock precisely. — II. Business shall commence
at seven o'clock, and be conducted in the following order:
1. The minutes of the preceding meeting rcijid a;id approved/

M 4 2, Notices

194 Geological Society.

2. Notices of new motions presented. 3. Members pr<i-f
posed. 4. Members balloted for. 5. Motions on the mi-
nutcR brought forward and determined. 6. Miscellaneoug
business. 7. Geological communications read, and presents
acknowledged. At nine o'clock the president shall leave
the chair. — III. All questions on which a difference of opi-
nion may arise^ shall be determined by ballot at the next or-
dinary meeting. — IV. If on any occasion the numbers be
equalj the chairman shall have a' second or casting vote. — ■

V. At the last meeting in June, the officers of the society
shall be elected -, the accounts of the late treasurer shall be
passed ; and a subscription raised to defray incidental ex-
penses incurred by him for the purposes of the society. — -.

VI. A special general meeting may at any time be called by
the secretary, in consequence of instructions received from
the president, or a requisition signed by three ordinary mem-
bers. The object must be stated to the secretary, who shall
give each member intimation of it, and of the time ancj
place of meeting, three days previously.

Of Cojnmunications, — All communications must be sent
to the secretary ; and, previously to their being read before
the society, shall be approved by a committee composed of
the officers of the society^ and of three members chosen by
ballot. Three to constitute a quorum. This committee
shall be appointed at the June meeting, after the election of
officers, and shall be trustees of all presents to the society.

OfFisitcrs. — T. Each member shall be at liberty to in-r
troducc a visitor ; besides whom the president, or chairmaa
for the time being, may admit any person he may think
fit, with the limitation specified in the succeeding article. — .
II. No person resident in London can attend more thari
two meetings of the society without becoming a member.

List of Officers,
Patron, Right Honorable Ch. F. Greville, F.R.S. &c.—
president, G.B. Grcenough, esq. M.P. F.R.S. — Vice-presi-
dents, William Babington, M.D. F.R.S,; H. Davy, esq.
Sec. R,S. Prof. Chem. R.I. ;— Treasurer, W. H. Pepys^
«fsq. ', — Secretary, J. Laird, M.D.

\ Ordinartf.

Geological Society ^ ^ » 185

Ordinary Members. f

Arthur "Alkin, esq. ; William Allen, esq. F.R.S. &c. j
Kight Honourable Sir Jos. Banks, hart. KJ3. Pres. R.S,
&c. ; M. le Cnmte de Boiimon, F.R.S. ; J. iFranck, M.D j
Richard Knight, esq. ; J. Parkinson, esq. ; Richard Phillips^
esq. ; William Phillips, esq. ; J. G. Ridout,esq. \
HoTwrary Members,
Thomas Allan, esq. Edinburgh ; Robert Bevan, M. D,
Monmouth ; Richard Bright, esq. Bristol ; Jos. Carne, esq.
Penzance ; M. P. Carter, M. D. Braintree; R. B. Cheston,
M.D. F.R.S. Gloucester; E.D. Clarke, L.L.D. Jesus
College, Cambridge ; William Clayficld, esq. Bristol ,; Rev.
J. J. Conybeare, Christ Church, Oxford ; David Crawford,
esq. Donegall ; J.Dennis, esq. Penzance ; L. W. Dillwyn,
esq. F.R.S* Swansea; F. Dugard, M.D. Shrewsbury 5
Right Honourable John Foster ; Rev. W. Gregor, Creed,
Cornwall ; J. Griffiths, esq. Mellecent, Ireland ; Rev. J.
Hailstone, Prof. Nat. Hist. Cambridge ; J. Hawker, esq.
Dudbridge, Gloucestershire ; J. Hawkins, esq. Sussex ;
Rev. J. Hincks, Cork ; T. C. Hope, M.D. Prof. Chem.
Edinburgh ; R.Jameson, Prof. Nat. Hist. Edinburgh ; J,
Kidd, M.D. Prof Chem. Oxford ; Richard Kirwan, esq.
I..L.D. F.R.S. P.R.I.A. Dublin ; Robert Lovell, M.D.
Bristol; J. Mac Donnell, M D. Belfa-^t ; Sir George
Mackenzie, hart. Inverness ; Thomas Meade, esq. Chatley,
Bath; H. Menish, M.D. Cheb^isford ; John Murray, esq.
Lect. Chem. Edinburgh; D. Mnshet, esq. Alfreston Irour
Works, Derbyshire ; Rev. Benjamin Newton, Chatley,
Bath; C. H. Parry, M.D. F.R.S. Bath ; Sir. Christopher
Pegge, F.R.S. Reg. Prof. Physic, Oxford ; J. Playfair,
Prof. Nat. Phil. Edinburgh ; Philip Rashleigh, esq. Mena-
billy, Cornwall ; William Rashleigh, esq. ; W. Richardson,
D.D. Portrush, Ireland ; . W. Roberts, M.D. Gloucester;
Lord Webb Seymour, Edinburgh ; John Taylor, esq.
Holwell-House, near Tavistock ; T. Thomson, M.D. Lect.
Chem. Edinburgh ; Rev. Jos. Townscnd, Pewsey, Wilt-
shire; Rev. W. Turner, Newcastle ; J. Ure, M.D. Glas-
gow ; J. Vivian, jun. esq. Truro ; J. Watt, jun. esq. Bir-
mingham; J^ Wilkinson, esq. Bath; J. Williams, jun.
esq. Scorrier House, Cornwall.

MEDICAL

J 86 Wcrneriaii Natural History Society*

MEDICAL SOCIETY OF LONDON.

This society held its anniversary meeting on Tuesday the
8th of March. After the election of office-bearers for the
ensuing year, Mr. Good, a distinguished member of this
learned body, delivered an extempore oration, the subject
of which was a survey of the theory of the general struc-
ture and physiology of plants, compared with those of ani-
mals ; the process by which vegetable matter is converted
into animal matter, so as to become the basis of animal nu-
triment and support; and the mode by which animal matter
is afterwards reconverted into vegetable, so as to complete
the circle of action, and to restore to plants the nutritive be-
nefit which has been antecedently derived from them.

In this interesting discourse, Mr. Good took a compre-
hensive view of the wisdom and goodness of the Creator,
which pervades the universe, and is manifested throughout
^e various and innumerable links of that chain by which
the endless varieties of organized beings are bound together,
and rendered mutually dependent on each other.

At the miauimous request of the society, Mr. Good has
consented to publish this oration, in as verbal a form as his
recollection may suggest to him.

WERNERIAN NATURAL HISTORY .SOCIETY.

A society has been established at Edinburgh for the cul-
tivation of the different branches of natural history. It is
denominated the fVerneriun Natural History Society ^ in ho-
nour of Werner.- The following gentlemen have been

elected office-bearers.

President — Robert Jameson, esq. F. R. S. Prof. Nat. Hist.
Edin. Vice-Presidents— VVm. Wright, M.D. F.R.S. ;
Rev. T. Macknight, F.R.S. ; .John Barclay, M.D. F.R.S. ;
and Thos. Thompson, M.D. F.R.S. i'atrick Walker,
esq. treasurer. Patrick Neil, e?q. secretary. Councils-nine
in number — viz. ihe above office-bearers, with Charles An-
derson, esq. F. R. C.S , and Lieut. Col. Fullerton of Barr
tonholm.

i:ir Joseph Banks ; Richar-d Kirwan, escj. president of the

Royal

Wernerian Natural History Society. 187

Royal Irish Academy ; and Professor Werner, of Freyberg,
were elected the first hoaorary members. The following fo-
reign members have been elected : — viz. Professor Karsten,
Berlin; Professor Klaproth, Berlin; M. Von Humboldt,
and M. Von Buch, also of Berlin. M. F. Mohs, of Stiria;
M. Herden, M. Meuden, and M. Friesleben, of Saxony.

At the last meeting of the Wcrnerian 'Natural History
Society, Protessor Jameson read a description of cotempo-
r.aneous or inclosed veins. He divided veins into two clas-
ses. The first class comprehend triie veins, the second cO'
temporaneous or inclosed veins. Some veins, he remarked,
excepting where the beds and strata are of very great thick-
ness, traverse many different strata or beds; and although
we do not always observe them open at the surface of the
earth, they invariably open at the surface of the formation
or series of formations they traverse : thus, the outgoing or
opening of certain metalliferous veins that traverse clay-slate
and mica-slate is sometimes covered by the second porphyry
formation. Cotemporaneous or inclosed veins are in general
iCopfine4 to individual beds or strata, and are fairly inclosed
in them, or in other words wedge out in every direction \i\
the bed or stratum ii) which they are contained.

After detailing thp various characters of true and cotem-
poraneous veins, ,the Professor next described the cotcm-
porapepus veins that occur in the different great rock- for-
mations, beginning with granite, and ending with the new-
est flaetz trap formation. He next explained the mode of
formation of these veins^ When describing the cotempo-
raneous veins that occur in gneiss, he remarked that cer-
tain varieties of yenigenous gneiss bear a striking resem-
blance to granite, and hence have been frequently confound-
ed with that rock. This led him to point out the cha-
racters by which true granite veins are distinguished from
veins of granitic gneiss. As connected with this part of the
subject, he examined the facts on which theHuttonian theorv
of granite is founded; and proved by h detail of his examina-
' ^ion of the appearances described by Dr. Hutton, Professor
play fair and others, that the supposed granite veins shooting

fro«)

168 A^eiv Booh.

from subjacent granite into superincumbent rocks, arc
merely veins of granitic gneiss accidentally in contact witli
granite.

XL. Intelligence and Miscellaneous Articles.

NEW BOOKS.

X ROFEssoR Jameson has just published the third volume
of his system of mineralogy, under the title Elements of
Geognosy. The contents of this important work arc as
follows : Chap. I. Description of the surface of the earth.
Chap. II. Effects of water on the surface of the earth.
Chap. III. Internal structure of the earth. Chap. IV. Ge-
neral account of the different formations, in regard to their
succession and stratification, and this illustrated by a short
description of the Hartz and Saxon Erzgebirge. Chap. V.
Theory of the diminution of the waters of the globe— De-
scription of overlying formations. — An investigation of the
original contents of ihe waters of the globe, during the diffe-
rent periods of the earth's formation — The division of rocks
into five classes. Chap.VI. Class 1. Primitive rocks. Chap.
VII. Class 2. Transition rocks. Chap. Vfll. Class 3. Fl^tz
rocks. Chap. IX. Class 4. Alluvial rocks. Chap. X. Class
5. Volcanic rocks. Chap. XL Mineral repositories. Chap,
XII. Relative age of metals, viz. 1. Molybdaena. 2. Me-
nachine. 3. Tin. 4. Schiele. 5. Cerium. 6. Tantalum.
7. Uren. 8. Chrome. 9. Bismuth. }0. Arsenic. ]1. Co-
balt. 12. Nickel. 13. Silver. 14. Copper. 15. Gold.
16. Sylvan. 17. Antimony. 18. Manganese. 19. Lead,
20. Zinc. 21. Mercury. 22. Iron. 23. Platina. — General
inferences. To these follow a table of 32 pages containing
the relative antiquity and geognostic relations of simple mi-
nerals : also an extensive table of the most remarkable heights
of mountains, hills, and lakes in different parts of the world,
and a table of volcanoes. The volume is concluded with a
series of notes explanatory of passages in the text, and re-
ferring to the Huttonian theory of the earth.

Mr,

Miscellaneous, Iggf

Mr. John Ayrton Paris, of Caius College, Cambridge,
and fellow of the Royal Medical Society, Edinburgh, ha»
now in the press, A Compendium of Modern Chemistry, in
the Latin Language; — a small work intended as the J^ofz^j
Achates of the medical as well as chemical ph.loiopher. It
treats not only of the principal subjects in chemistry, but
unfolds the processes by which the different compounds of
the London and Edinburgh pharmacopoeise are prepared,
and the theories upon which such operations are founded.
The analyses also of animal and vegetable bodies are as fully
given as the prescribed limits of a compendium will allow. —
This work will also afford easy instructions for the disciple of
the Stahlean school to become the proselyte of Lavoisier, —
The language in which it is written, will, it is hoped, render
it no inconsiderable assistant to those desirous of writincr or

o

speaking medical Latin. And if it be remembered that no
such publication has appeared in the chemical department
subsequent to Boerhaave, the hope may not be presump-
tuous.

CULTIVATION OF INDIGO IN FRANCE.

i,.; A proceS'Verhal oi the municipality of Lille, in the de-
partment of Vaucluse, has lately stated the success of a
plantation of indigo, executed on a large scale and in the
the open air at an estate belonging to M. Icard de Bataglini,
an agriculturalist. It is stated in the Proces-verbal, that
after an attentive examination of the indigo produced, the
commissioners were of opinion that this precious plant may
be naturalized in the department, and become a principal
source of its riches.

MISCELLANEOUS.

New Method of takhig Stains out of Linen. — Lemon-juice
has generally been employed for this purpose ; — but a German
journal devoted to subjects of rural oeconomy, and edited
.by M. Schnee, gives another more ceconomical, but not
less certain, method, by means of aqua fortis. One or two
drops are sufficient for taking out a large spot of ink with-
«^ut damaging the linen : it is only necessary previously to

xnoisten

tgO Miscellaneous,

moisten the spot with water, aud to rinse it afterwards ill
water also.

Remedies against the Epidemy in Cattle. — 'It has been
long known that nettles form an excellent food for cattle,
and that they increase the milk of cows. This plant is also
an excellent remedy against epidemical diseases^ which
are frequently the effect of bad food in the stable. In
Sweden the salutary effects of nettles are particularly con-
spicuous, where they are administered to the horned cattle
regularly every spring in great quantities,

M. Scheidlin, botanist to the court of Wirtemberg, has
proved by a multitude of experiments that Angelica (Ange-
lica satis^a hortensis, Linn,) is an excellent preservative
against cattle epidemics. EJe bruized the roots of this plant,
and gave a handful to each cow, morning, noon, and night,
along with its ordinary food. Cows ate it greedily, and
were not attacked with the disease. He also mixed it with
the water they drank.

The leaves and roots of Angelica dried and reduced into
powder, and strewed over bread, or other food, have the
same virtues. This root grows spontaneously in shady and
humid places, and it may be planted with good effect in
case of need.

Mastic for resisting the Action of Fire and IVaier.^-^Thc
following directions are given in the foreign journals, for
preparing a composition of this description { — Take half a
pint of milk, mix with it an equal quantity of vinegar, so
as to coagulate the milk ; separate the curds from the whey,
mix ihe latter wiih the whites of four or five eggs, after having
beat them well up. The mixture of these two substances
being complete, add quick-lime to them which has been
passed through a sieve ; make the whole into a thick paste
to be of the consistency of putty, when you use it.

If this mastic is carefully applied to broken bodies or to
fissuresof any kind, and dried properly afterwards, it resists
water and fire. M. Skogo, a merchant of Carlskrona,
closed a hr^ crack in the bottom of a large iron cauldon, m

which

List of Patenisfor New Inventions, 191

which he frequently boils pitch, and this cauldron has now-
served him for five years in this state without requiring any
further repairs,

NAUTICAL INVENTION.

A gentleman has lately invented a very simple and i»g«-
nious method by which a v,essel without any person on board
can be directed with very considerable accuracy in a given
course. The application of this invention to fire-ships
would be of vast utility: and that this may be judged of wrth-
out (for obvious reasons) giving a public description of the
means by which it is effected, the model used in the first
experiments, which we understand were completely satisfac-
tory, may be seen at Mr. Thomas Jones's, mathematical,
optical, and philosophical instrument maker. No, 124,
Mount-street, Berkley-square.

LIST OF PATENTS FOR NEW INVENTIONS.

To John Dumbell, of Mersey Mills, in the parish of
Warrington, and county palatine of Lancaster, miller ; for
his invented method or methods of obtaining, producing,
using, and cultivating a moving power or force; and of
communicating motion to engines, pumps, and machinery,
and to mechanical operations in general; and of forming and
using a rotary or circular motion, or a motion to and fro ad
libitum; and a method or methods of working and apply-
ing the same to milL;, machinery, ploughs, tools, and equi-
page in general, and almost to an endless variety of valuable
purposes, and in particular to carriages ; and also a method
or methods of making less disastrous and less frequent the
overturning of carriages, apd of improving their structure,
and of guiding and governing the same : — which carriages or
mechanism, when embracing his appendages and conceits,
he distinguishes by the name of Ess or George's Wain.
February 4.

To Samuel Brown, a lieutenant in the royal navy, and
now residing in Casllc-court, Budge-row, Watling-street,
in the city of I^ndon, for his inventions and improvements
in the rigging of shrps or vessels. February 4.

. _ METEORO-

193

Meteorology,

meteoiiological table,

By Mr. Carev, op the Strand*^

For March 1808.

D^ys of the

Month.

Thermometer.

Height of

the Barom.

Inches.

w >■ C

Weathef.

Feb. 25

26

27

28

29

March 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

34'

30

40

38

45

47

49

47
83
35
33
32
32
32
32
32
33
38
35
34
37
32
32
32
40
36
36
31
33
25
32

37°

36

49

48

52

52

53

49

51

43

45

4i

38

43

41

42

39

42

41

44

41

34

34

37

47

39

41

36

36

36

42

30°

39

39

45

46

48

46

41

35

34

33

33

32

33

33

35

37

3b

35

36

32

29

29

36

40

37

30

31

29

32

35

30-69

•49
•38
•35
•15
•28
•31
•35
•44
•42
•42
•28
•28
•32
•34
•32
•30
•19
•10
29*99
•98
•99
•87
'6b
'bb
'7b
•92
. '92
•90
•92
•96

26

20

31

25

10

11

24

31

15

27

30

38

21

23

19
21
15
25
19
26
25
15
15
14

5

8
16
27
25
30
15

Fair
Fair
Fair
Fair
Cloudy
Cloudy
Cloudy
Cloudy
Fair
Fair
Fair
Fair
JFair
Fair
Cloudy
Cloudy
Cloudy
Cloudy
Cloudy
Fair
Fair
Cloudy
Cloudy
Cloudy
Cloudy
Cloudy
Fair
Cloudy
Cloudy
Fair
Fair

N.B. The Barometer's height is tak^n atone o'clock.
Xii I III

'I'.^.V: ^ [ 193 1 • *-^— »ir,0 ^« t

,. .J\tr . -<n ; 'i^kt

^Ll, Experiments on the Influence of Time, as a Chemical,

* jge?ii, in depriving an Elastic Fluid of its Elasiicitj/*

In a Letter fiom M. BioT to M, Berthollet *. , .

1. i!«'i-b 'Iff' ff'l' -t ::,rriO0
HAD lately occasion to converse with that excellent ob-
server M. de Marty, upon the sulycct of several experiments,
with which he has been a long time occupied, and I havQ^
received his permission to make iheni public.

The experiments which I shall first mention, have for
their object the influence of time upon the exercise of che-
mical actions, when they tend to deprive an elastic fluid o(^
its elasticity :

1. Into a glass flask, closed with a ground stopper,.
M. dc Marty introduced a certain quantity of oxygen gas ,
and a certain quantity of rain water boiled or not boiled. J '
There may be any proportions of water and gas. Supposing^
that tiitre is but a small quantity of water; by shaking this
mixture for some minutes the water will absorb a certain
quantity of gas, as may be ascertained upon opening the
flask into a tub full of water. But after having shaked it
arid opened it several times, the water contained in the flask
will soon finish by being saturated, and will absorb no
more.

Things being thus disposed, close up the flask and place
it out of the reach of the sun ; observe at the same time the
barometer and thermometer: then after two or three days
of rest, shake the flask again and open it under the water,
and you will see the latter ascend a little : close the flask,
return it to its place and renew the shaking from time to
'time ; you will find that it has every time absorbed a new
quar.i'ty of gas. This eflect will appear so much the more
striking, the longer time it has been since you last opened
the fl<isk. and in this case the water of the tub will rise
much more than if you had opened it within a few days.

I have witnessed these eff'ects at M. Marty's house. He
uncorked under water, in my presence, a flask which had
been closed upwards of a year and a half, and which coa-

• From /4nn. de Chimie, torn. Ixi. p. 271.

Vol. 30. No. 119. v^j&^iV 1608. N taincd

1 94 On the Injluence of Tlme^ as a Chemical Agent, &c,

U'lned oxygen gas with a small quantity of water. Whca
the flask was opened in the tub, the water of the latter rose
in a very remarkable manner, and the absorption appeared to
me to he equal to at least half the volume of the water
contained in the flask before we opened it ; the barometej
and thermometer were nearly at the same height as at the
moment of introduction : the temperature of the water of
the tub was also the same.

It seems therefore from this experiment, that the same
mass of water which at first could only absorb a certain
volume of oxygen gas, absorbed a considerable volume of
It after some time ; whence it should seem, that in the first
case the air was but feebly combined, and in some measure
interposed between the particles of the water. But th»
prolonged action of the liquid, diminishing more and more
the elasticity of the gas, and contracting it as It were by
degrees, made it enter further forward into the sphere gf.
attraction of its particles, which has rendered the water
susceptible of absorbing a new quantity of gas.

2. The same thing takes place relative to hydrogen gas,
which I also witnessed at M. Marty's. The absorption, in
this case, was equally strong, and M. Marty finds by his
experiments that the volume absorbed is more considerable,
and the absorption more speedy, with this gas than with oxy-
gen gas. He found, also, tha^ in two years the volume of
gas absorbed was not equal to the volume of the water.

3. Water already charged with oxygen is more proper for
absorbing hydrogen, and vice versa: this is analogous to
what was remarked by Messrs. Humboldt and Gay Lussac.
M. Marty's experiments, however, have the advantage of
having been made in close vessels.

4. The absorption is the more considerable in proportion
as the volume of water is greater.

5. These eflfects do not take place with azotic gas : after
once shaking the water for some time with this gas, it does
not absorb an atom more, however long time we leave it in
contact.

6. If we put water charged with azot in contact with hy-
drogen or oxygen gas, it absorbs these gases vvithout aban-
doning

bxpefmentsfor ifivesttgatingy &c. ' i^5

(Zoning the azot it contains. If we tbink there has b^ch a
change, it is, in fact, because a little azol escapes at the
commencement of the absorption of the hydrogen or oxy-
giin 'f but shake the water and the gaf?es together, the whole
azot which was previously interposed iA thcJ' water will en-
ter into it and interpose itself as formerly, independently of
the hydrogen or oxygen gas, which it has beside absorbed.

7. The preceding result is so coi'rect that we may exactly
analyse the atmospheric air by the simple absorbent action of
water. For this purpose it is sufficient that the water has
been previously impregnated with azot } it :then absorbs
precisely ^1 hundredths of the atmospheric air put in con-
tact with it, as a sulphuret would do. M. Marty asserts
that the water thus empioyed in great quantities, in order
that the operation may be more expeditious, is an excellent
eudiometer, and that he used it as such frequently. If we
have no aZot at hand, we may impregnate the water wil^
this gas by shaking it with atmospheric air, and leaving it for
some time in contact with this air : by this means it absorbs
all the azot it ought to contain ; and the oxygen it takes at
the same time does not hinder it, according to the first ex-
periment, from absorbing in time, that of the air we mean
to analyse. M. Marty also uses this absorbent property of
water to ascertain if a given oxygen gas does or does not
contain azot ; for if it does contain it, the water saturated
with azot does not absorb it completely.

XLII. Experiments for invest] gating the Cause of the co-
loured concentric RingSy discovered hj Sir Isaac Newton,
tetween two Object-glasses laid upon one another. jSy
WiLLiAM Herschel, LLD, F.R.S,

[Concluded from p. 128.]

XXV. Of the Action of the second Surface,

Ag fings are fofrficd whe-n two glasses are laid upon- each
other, it is but reasonable to expect that the two- surfaced at
leasf which aref lacfidtogab^ fliouldhaiv^ an iitime<jRate^ effect

N S upon

196 Experiments for invesilgating

upon -them, and so much the more, as it has been asccr-»
tained that the first surface assists only by permitting light
to pass into the body of the glass. Some of the experi-
;^r)t?ents that have' been instituted for examining- the action of
.the first surface will equally serve for investigating that of
the second.

Hk lens already used with a strong emery scratch being
■again placed on the mirror, but with the injured side down-
wards, 1 found that the rings, when brought under the
scratch, were not distorted ; they had only a black mark cf
the same shape as the scratch across them.

The lens with a scabrous side was also placed again upon
the mirror, but with the highly polished side upwards. In
this position the scabrousness of the lowest surface occa-
sioned great irregularity among the rings, which were in-
dented and broken wherever the little polished holes that
make up a scabrous surface came near them ; and if by
gently lifting the lens a strong contact was prevented, the
colours of the rings were likewise extremely disfigured and
changed.

. As we have now seen that a polished defect upon the
second surface will affect the figure of the rings that are
under them, it will remain to be determined whether such
defects do really distort them by some modification they
give to the rays of light in their passage through them, or
whether they only represent the rings as deformed, because
we see them through a distorted medium. For although the
scabrousness did not sensibly affect the figure of the rings
when it was on the first surface, we may suppose the little
polished holes to have a much stronger effect in distorting
ihe appearance of the rings when they are close to them.
TRe following experiment will entirely clear up this point.

Over the middle of a 22-inch double convex lens T drew
a strong line with a diamond, and gave it a polish after-
wards that it might occasion an irregular refraction. This
being prepared, T laid a slip<^f glass upon a plain metalline
mirror, and placed the lens with the polished line down-
wards upon the slip of gla^s. This arrangement lias been
fhown to give two sets of rings. When I examined the
.^J- ■ " . primary

the Cause of coloured concejiiric Rings. 197

primary set, a strong disfiguring of the rings was visible ;
they had the appearan^cc of having been forced asnndcr, or
swelled out, so as to be much broader one way than an-
other. The rings of the secondary set had exactly the
ffame defects, which being strongly marked, could not he
mistaken. The centres of the two sets, as usual, were of
opposite colours, the first being black, the second whiti^;
and all those defects that were of one colour in the first set,
were of the opposite colour in the second. When, by the
usual method, I changed the colours of the centres of the
rings, making that of the primary vvhite and of the secoQ-
dary black, the defects in both sets were still exactly alike,
and as before ; except that they had also undergone the 4ike
transformation of colour, each having assumed its opposite^
It remains now only to show that this experiment is deci;-
sive ; for by the established course of the rays we saw the
sepondary set of rings when it had a white centre by the
transnjitted r^ys marked 1, 2, 4, 5, in figure 13; and when
it had a black ope, by the reflected rays 6, 7, 2, 4, 5, of
the same figure ; but in neillher of these two pases did the
rays come through the defective part of the kna iq. their
return to the eye.

This experiment proves more than we might at first be
aware of; for it does not only establish that the second
surface, when properly combined with a third surface, has
a modifying.power whereby it can interrupt the regularity
of the rings, but also one whereby it contributes to their
formation ; for, if it can give an irregular figure to them by
transmitting its irregularly modified rays, it follows, that
when these rays are regularly modified it will be the cause of
the regular figure of the rings. Nay, it proves more ; for if
it modifies the figure of the rings by transmission, it modi->
fies them no less by reflection; which may be seen by foU
bwing the course of the rays 6, 7, 2? 4, 5 ; for as they do
not pass through the defective place of the lens, they can
only receive their modification from it by reflection. This
opens a field of view to us that leads to the cause of all these
intricate phsenomena, of which in a second part of this
paper I shall avail myself. < -Sjtj^^^y.

N3 XXVI. Of

1 $8 Experiments for investigaihtg

XXVI. Of the Action ef the third Snrfoce,
When a double convex lens is laid upon a plain metalline
mirror that happens to have an emery scratch in its surface,
we see it as a black line under the rings that arc formed over
them. This shows, that when a defect from want of polish
has not a power to reflect light in an ii regular manner, it
cannot distort the rings that are formed upon it.

When I laid fi good 21 -feet object glass upon a plain slip
that had some defects in its surface, the rings, in every part
of the object glass that was brought over them, were always'
disfigured ; which proves that a reflection from a defective
third surface has a power of forming distorted rings, and
that consequently a reflection from one that is perfect must
have a power of forming rings without distortion, when it
id combined with a proper second surface.

When the defective slip of glass, with a perfect lens upon
it, was placed uppn a metalline mirror, T saw the secondary
stt affected by distortions of the rings that were perfectly
like those in the primary set; which proves that a polished
defect in the third surface will give modifications to the rays,
that form the rings by transmission as well as by reflection.

XXVII. The Colour of the reflecting mid transmitting Sur-
faces is of no consequence.

I laid seven 54-inch double convex lenses upon sevea
coloured pieces of plain glass. The colours of the glasses
were those which are given by a prism, namely, violet,
indigo, blue, green, yellow, orange, and r^d. The rings
yeflcctcd from each of these glasses were in every respect
alike^ at least so far that I coxdd have a black, a white, a
red, an orange, a yellow, a green, or a blue centre with
every one of them, according to the degree of pressure I
used. The lenses being very transparent, it may be admit-
ted that the colours of the glasses seen through them would
m some degree mix with the colours of the rings; but the
action of the cause that gives the rings was not in the least
affected by that circumstance.

I saw the rings also by direct transmission through all

the coloured glasses except a dark red, which stopped sq

. "-"/y -. much

the Cause ^ toloured concentric Rings, 199

much fight that I could nxrt perceive them. The co-
lour of the glasses, in this way, coming directly to the eye,
gave a strong tinge to the centres of the rings, so that in-
sreadof a pure white I had a blueish white, a greenish white,
and so of the rest ; but the form of the rings was no less
perfect on that account.

XXVIII. Of the Action of the fourth Surface.

We have already seen that a set of rings may be com-
pletely formed by reflection from a third surface, without
the introduction of a fourth : this, at all events, must provt
that such a surface is not essential to the formation of rings ;
but as not only in direct transmission, but also When two
sets of rings are to be seen, one of which may be formed by
transmission, this fourth surface must be introduced, I have
ascertained by the following experiments how far the same
has any share in the formation of rings. jotll

In direct transmission, where the light comes from l)e-
low, the fourth surface will take the part which is acted by
the first, when rings are seen reflected from a metalline
mirror. Its office therefore will be merely to afford an en-
trance to the rays of light into the substance of the subjii^
cent glass ; but when that light is admitted through the
iirst, second, and third surfaces, the fourth takes the office
of a reflector, and sends it back towards the poirit of con-
tact. It will not be required to examine this reflection,
since the light thus turned back again is, with respect to
the point of contact, in the same situation in which it was
after its entrance through the first surface when it proceeded
to the same point ; but when two sets of rings are to be
formed by rays, either coming through this point dirfcCtly
towards the fourth surface, or by reflection from the same
point towards the place where the secondary rings are to be
seen, it will then be necessary to examine whether this sur-^
face has any share in their formation, or whether these rings,
being already completely formed, are only reflected by it to
the eye. With a view to this, I selected a certain polished
defect in the surface of a piece of coach-glass, and when
:MAA. N4 a 26-inch

(UPD ETpetiments for investigating ' ^

a 56- inch lens was laid upon it, the rings of the set it pro-
duced were much distorted. The lens was then put upon a
perfect slip of glass, and both together were laid upon the
defective place of the coach-glass. The rings of the secon-
dary set reflected by it were nevertheless as perfect as those
of the primary set. It occurred to me that these rings might
possibly be reflected from the lowest surface of the perfect
slip of glass, especially as by lifting it up from the coach-
glass I still continued to see both sets. To clear up this
point, therefore, I took away the slip, and turning the de-
fective place of the coach -glass downwards, produced a set
of perfect rings between the lens and the upper surface of
the coach-glass, and brought it into such a situation that a
secondary set must be reflected from the defective place of
the lowest surface. This being obtained, the rings of this
set were again as well formed and as free from distortions as
those of the primary set.

Upon a plain metalline mirror I laid down two lenses,
'one a plano-convex, the other a plano-concave, both of
2*9 inches focus, and having the plain side upwards. When
two 21 -inch double convex glasses were laid upon them,
the secondary sets of both the combinations were of equal
size, and perfectly like their primary sets ; which proves
that the refraction of the fourth surface is either not at all
concerned, or at least has so little an effect in altering the
size of the rings that it cannot be perceived.

The result of the foregoing experiments, relating to the
action of the several surfaces, is,

I. That only two of them are essential to the formation
of concentric rings.

II. That these two must be of a certain regular construc-
tion, and so as to form a centra! contact.

III. That the rays from one side or the other, must either
pass through the point of contact, or through one of the sur-
faces about the same point to the other to be reflected from it.

IV. And that in all these cases a set of rings will be
formed, having their common centre in the pl^ce where the
two surfaces touch each other.

XXIX. Coa-

ike Cause of coloured concentric Rings. 201

Considerations t/tat relate to the Cause of the Forma-
tion of concentric Rings.

It is perfectly evident that the phseiiomena oF concentric
rings must have an adequate cause, either in the very
nature or motion of the rays of light, or in the modifica-
tions that are given to them by the two essential surfaces
that act upon ihem at the time of the formation of the rings.

This seems to reduce the cause we are looking for to an
alternative that may be determined ; for if it can be shown
that a disposition of the rays of light to be alternately re-
flected and transmitted cannot account for the phaenomena
■which this hypothesis is to explain, a proposition of ac-
counting for them bv modifications that may be proved,
even on the very principles of Sir I. Newton to have an ex-
istence, will find a ready admittance. I propose, therefore,
now to give some arguments, which will remove an obsta-
cle to the investigation of the real cause of the formation of
the concentric rings ; for after the very plausible supposi-
tion of the alternate fits, which airrees so wondcrfullv "weli
with a nuniber of facts that have been related, it will hardly
be attempted, if these should be set aside, to ascribe some
other inherent property to the rays of light, whereby we
might account for them ; and thus we shall be at liberty to
turn our thoughts to a cause that may be found in the mo-
difications arising from the action of the surfaces which
have been proved to be the only essential ones in the forma-
tion of rings.

XXX. Concentric Rings cannot he formed Ij/ an alternate
Reflection and Transmission of i lie Rays of Light.

One of the most simple methods of obtaining a set of
concentric rings is to lay a convex lens on a plain metalline
mirror ; but in this case we can have no transmission of
rays, and therefore we cannot have an alternate reflectioo
and transmission of them. If to get over this objection it
should be said that, instead of transmission, we ought to
substitute absorption 5 since those rays which ifi glass woulii

have

SOS ^xp^iments/orinvestigaimg

have been transmitted will be absorbed by the metal, we
may admit the elusion ; it ought however to have bten made
a part of the hypothesis.

XXXI. Alternate Fits of easy Reflection and easy Trans-
mission, if' they exist, do not exert themselves according
to various Thicknesses of thin Flates of Air,
In the following experiment, I placed a plain well po-
lished piece of glass 3*6 inches long, and 2*3 thick, upon a
plain metalline mirror of the same length with the glass ;
and in order to keep the mirror and glass at a distance from
each other, I laid between them, at one end, a narrow
strip of such paper as we commonly put between prints.
The thickness of -that which I used was the 6l0th part of
an inch; for 128 folds of them laid together would hardly
make up two-tenths. Upon the glass I put a 39-inch
double convex lens ; and having exposed this combination
to a proper light, I saw two complete sets of coloured rings.
In this arrangement, the rays which convey the secondary
set of rings to the eye must pass through a thin wedge of
air ; and if these rays are endowed with permanent fits of
easy reflection, and easy transmission, or absorption, their
exertion, according to Sir I. Newton, should be repeated at
every different thickness of the plate of air, which amount^
to the y-ir4<3ir P^i't of an inch, of which he says *' Haec est
crassitudo aeris in primo annulo obscure radiis ad perpendi-
culum incidentibus exhibito, qua parte is annulus obscuris-
simus est." The length of the thin wedge of air, reckoned
from the line of contact, to the beginning of the interposed
strip of paper, is 5*2 inches, from which we calculate that
it will have the above-mentioned thickness at -J^ of an inch
from the contact ; and therefore at -^, -^, -^^, ^, -^f^ ^-|-,
&c. we shall have the thickness of air between the mirror
and glass, equal to tW^^, TT-^oins-^ -rr^'oinr* tt^oo o> &c.
of which the same author says that they give ^^crassitudines
aeris in omnibus annulis lucidis, qua parte illi lucidissimi
sunt.'' Hence it follows that, according to the above hy-
pothesis, the rings of the secondary set which extended
8 over

'th^ Cause of coloured coTwentr'w Rings, SOS-

over a space of '14 of an inch, should suffer more than seven
interruptions of shape and colour iu the direction of the;
wedge of air.. .^^.^..y/

In order to ascerUin whether such an effect had any ex^
i^tence, I viewed the secondary set of rings upon every part
of the glass-plate, hy moving the convex lens from one end
of it gradually to the other; and my attention being parti-
cularly directed to the 3d, 4th, and 5th rings, which were
extremely distinct, I saw them retain their shape and colour
all the time without the smallest alteration.

The same experiment was repeated with a piece of plain
glass instead of the metalline mirror, in order to give rooni
for the fits of easy transmission, if they existed, to exert
themselves; but the result was still the same ; and the con-
stancy of the brightness and colours of the rings of the
secondary set, plainly proved that the rays of light were not
affected by the thickness of the plate of air through which
they passed.

XXXI T. Alternate Fits of easy Reflection and easy Trans^
" mission, if' they exist, do not exert themselves according
to various Thicknesses of thin Plates of Glass.
I selected a well polished plate of coach-glass 1 7 inches
long, and about 9 broad. Its thickness at one end was 33,
and at the other 31 two-hundredths of an inch ; so that in
its whole length it differed -J-^ of an inch in thickness. By
measuring many other parts of the plate I found that it was
very regularly tapering from one end to the other. This
plate, with a double convex lens of 55 inches laid upon it,
being placed upon a small metalline mirror, and properly
exposed to the light, gave me the usual two sets of rings.
In the secondary set, which was the object of my attention^
I counted twelve rings, and estimated the central space be-
tween th^pi to be about J -^ times as hroacj as the space taken
up by the 1 2 rings on either side ; the whole of the space
taken up may therefore be reckoned equal to the breadth of 40
rmss of a niean size : for the 12 rings, as usual, were gra-
dufuly contracted in breadth as they receded from the centre j
and, by a measure gf the whole space thus taken up, I

found

204 T xperimcnt$ for investigating

found that the breadth of a rin^ of a mean size was about
the 306th part of an inch.

Now, according to Sir I. Newton's calculation of the ac-
tion of the fits of easy reflection and easy transmission in
thick glass plates, an alternation from a reflecting to a trans-
mitting fit requires a difference of yj-^Vrr part of an inch in
thickness*; and by calculation this diflfercnce took place in
the glass plate that was used at every 80th part of an inch
of its whole length : the 12 rings, as well as the central
colour of the secondary set, should consequently have been
broken by the exertion of the fits at every 80th part of an
inch ; and from the space over which these rings extended,
which was about '13 inch, we find that there must have
been more than ten such interruptions or breaks in a set of
which the 308th part was plainly to be distinguished. But
when I drew the glass plate gently over the small mirror,
keeping the secondary set of rings in view, I found their
shape and colour always completely well formed.

This experiment was also repeated with a small plain glass
instead of the metalline mirror put under the large plate. In
this manner it still gave the same result, with no other dif»
ference but that only six rings could be distinctly seen in
the secondary set, on account of the inferior reflection of
the subjacent glass.

XXXIII. Coloured Rings may he completely formed without
the Ass'istance of any thin or thick Plates, either of Glass
or of Air,

The experiment I am now to relate was at first intended
to be reserved for the second part of this paper, because it
properly belongs to the subject of the flection of the rays o£
light, which is not at present under consideration ; but as it
particularly opposes the admission of alternate fits of easy
reflection and easy transmission of these rays in their pas-
sage through plates of air or glass, by proving that their
assistance in the formation of rings is not rcijuired, and also
throws light upon a subject that has at diflferent times been

* Newton's Optics, p. 277.

considered

th^fyuse of. coloured concentric Rings, SOS

considered by some of our most acute experimentalists, I
have used it at present, though only in one of the various
arrangements, in which I shall have occasion to recur. Uv it
hereafter.

Sir I. Newton placed a concave glass mirror at double its
focal length from a chart, and observed that the reflection of
a beam of light admitted into a dark room, when thrown
upon this mirror, gave *^ four or five concentric irises or
rings of colours like rainbows*." He accounts for them
by alternate fits of easy reflection and easy transmission ex-
erted in their passage through the glass- plate of the con-
cave mirror f.

The duke de Chaulncs concluded from his own experi-
ments of the same phaenoraena, " that these coloured rings
depended upon the first surface of the mirror, and that
the second surface, or that which reflects them after they
had passed the first, only served to collect them and throw
them upon the pasteboard, in a quantity sufficient to make
them visible J.'*

Mr. Brougham, after having considered what the two
authors I have mentioned had done, says, ^* that upon the
whole there appears every reason to believe that the rings are
formed by the first surface out of the light which, aj'ter re-
flection from the second surface, is scattered, and passes on
to the chart §.''

My own experiment is as follows, I placed a highly po-
lished 7-feet mirror, but of metal instead of glass, that I
might not have two surfaces, at the distance of 14 feet from
a white screen, and through a hole in the middle of it one-
tenth of an inch in diameter I admitted a beam of the sun
into my dark room, directed so as to fall perpendicularly on
the mirror. In this arrangement the whole screen remained
perfectly free from light, because the focus of all the rays
which came to the mirror was by reflection thrown back
into the hole through which they entered. When all was
duly prepared, I made an assistant strew some hair-powder

♦ Newton's Optics, p. 2G5. f Ibid. p. 577.

\ Priestley's History, &c. on the Colours of thin Plates, p. 515-
§ Philosophical Transactions for 1796, p. SI 6. .. : P^

with

50(J Erpermentsfor invest'} ^aibig, &c,

tvith a puflT into the beam of light, while t kept my atten-
tion fixed tipon the Screen. As soon as the hair-powde^
reached the beam of hght the screen was suddenly covered
with the most beautiful arrangement of concentric circles
displaying all the brilliant colours of the rainbow. A great
variety in the size of the rings was obtained by making the
Assistant strew the powder into the beam at a greater distance
from the mirror; for the rings contract by an increase of the
distance and dilate on a nearer approach of the powder.

This cxpei-imcnt is so simple, and points out the genera!
Causes of the rmgs which are here produced in so plain a man^
ner, that we may confidently say they arise from the flection of
(he rays of light on the particles of the floating powder, mo-
dified by the Curvature of the reflecting surface of the mirror.

Here we have no interposed plate of glass of a given
thickness between one surface and another, that might pro-
duce the colours by reflecting some rays of light and trans-
mitting others; and if \Ve were inclined to look upon the
distance of the particles of the floating powder from the
mirror as plates of air, it would not be possible to assfgn
any certairi thickness to them, since these particles may be
Spread in the beam of light over a considerable space, and
perhaps none of them will be exactly at the same distance
from the mirror.

I shall not enter into a further analysis of this experi*
ment, as the only purpose for which it is given in this place
is to show that the principle of thin or thick plates, either
of air or glass, on which the rays might alternately exert
their fits of easy reflection and easy transmission, must be
given up, and that the fits themselves of course cannot be
shown to have any exisistence.

XXXIV. Conclusion.
It will hardly be necessary to say, that all the theory re-
lating to the size of the parts of natural bodies and their in-
terstices, which Sir I. Newton has founded upon the e:ti^-
tence of fits of easy reflection and easy transmission, exerted
differently, according to the different thickness of the thin
plates of which he supposes? the parts of natural bodies to

consist.

On Machines in General* koi

consist, will remain unsupported ; for if the above-men-
tioned fits have no existence, the whole foundation on which
the theory of the size of such parts is placed, will be taken
away, and we shall consequently have to look out for a
more firm basis on which a similar edifice may be placed.
That there is such a one we cannot doubt, and what 1 have
already said will lead us to look for it in the modifying
power which the two surfaces, that have been proved to be
essential to the formation of rings, exert upon the rays of
light. The second part of this paper, therefore, will enter
into an examination of the various modifications that light
receives in its approach to, entrance into, or passage by,
differently disposed surfaces or bodies ; in order to discover,
if possible, which of them may be the immediate cause of
the coloured rings that are formed between glasses.

XLIII. Essay upon Machines in General, Bij M. Carnot,
Member of the French Institute, ^c. ^c,

[Continued from p. 158.]

X. J. HE science of machines in general is therefore re-
duced to the following question r

** Being acquainted with the virtual movement of any
system of bodies {that is to say,, that movement which each
of these bodies tvaidd take if it ivere free), find the real move^
ment which will take place the instant following, on account
of the reciprocal action of bodies^ by considering them suck
as they exist in nature y i.e. as endowed with all the inertness
common to all the particles of matter,** ;/ Wij) I

XI. Now, as this question evidently contains, the whole
of mechanics, we must, in order to proceed with precision,.
go back to the first laws which nature, observes in the com-
munication of movements. We may reduce them in general
to two, which are the following :

FUNDAMENTAL LAWS OF EQUILIBRIUM, AND MOTION.

First Law.— ^c^iow and Reaction are always equal and
contrary.

This

fiOS On Machines in GeJicraL

This law consists in this, that every body which changes
its state of repose or uniform and rectilinear motion,
never does sd except by the influence or action of some
other body, upon which it impresses, at the same lime, a
<}iianlity of motion eqnal and directly opposite to that
which it receives from it ; that is to say, that the velocity
it assumes the instant afterwards is the force resulting from
that which this other body impresses upon it, and from that
which it would have had without this last force. Every
body therefore resists Its change of state ; and this resistances^
which is called vis inerticey is always equal and directly op-;
posite to the quantity of motion it receives, i, e. to the
quantity of motion which combined with that which it
had immediately before the change, produces, as the result,
the quantity of motion which it should really have im-
mediately afterw-ards. This is also expressed by saying, that
in the reciprocal action of bodies, the quantity of mo-
tion lost by the one is always gained by the others, in the
fame time and in the same ratio.

Sfxond Law. — IVhen two hard bodies act upon each
other, hy shock or pressure, i. e. in 7'irtue of their inpene-
trabiliti/, their relative velocity y immediately after the reci-
procal action, is always juilL

In fact, we constantly observe, that if I wo hard bodies
give a shock to each other, their vefocities, immediately
after the shock, estimated perpendicularly to their commoft
surface at the point of contact, are equal, in the same way
as if they were drawn by inextensihle wires, or pushed
by incompressible rods ; their velocities, estimated in the
ratio of this wire or rod, would necessarily be equal : whence'
h follows that their relative velocity, e. e, that by. which
they approach or recede from each other, is in every case
null at the hrst instant.

From these two principles it is easy to draw the laws of
the shock of hard bodies, and consequently to conclude the
two other secondary principles, the use of which is continual
in mechanics, viz.

1. That the intensity of the shock, or of the action which

18

I

On Machines in General. 20$^:

id exercised between two bodies which meet, does not de-'
pend upon their absolute movements, hut solely upon their^
relative movements. 2. That the force or quantity ofmov^-^^
ment which they exercise upon each other, hy the shock, is'
always directed perpendicularly to their common surface at
the point of contact. ^>Vi3biP

XII. Of the two fundamental laws, the first generally
agrees with all the bodies of nature, as well as the two se-
condary laws which we have seen ; and the second solely
regards hard bodies ; but as those which are not hard have
different degrees of elasticity, we generally refer the laws of
their movement to those of the hard bodies, which we take
for a term of comparison, i. e. we regard the elastic bodies
as composed of an infinity of hard corpuscles separated by
small compressible rods, to which we attribute all the
elastic virtue of these bodies ; so that, properly speaking, we
do not consider in nature any other than bodies endowed
with different moving forces. We shall follow this method
as the simplest : we shall therefore reduce the question to
the investigation of the laws observed by hard bodies, and
shall afterwards make some applications of them to cases
in which bodies are endowed with different degrees of
elasticity.

XIII. This essay upon machines not being a treatise
upon mechanics, my object is not to explain in detail, nor
to prove the fundamental laws I have related ; these are
truths which all the world knows, as to which they are
generally agreed, and which are most strongly manifested
in all the phsenomena of nature. This is sufficient for my
object, which is merely to draw from these laws a simple
and exact method for finding the state of rest or of move-
ment which results from them in any given system of bo-
dies, i. e, to present the same laws under a form which
may facilitate their application to each particular case.

XIV. Let us suppose therefore any system of hard bo-
dies, the virtual given movement of which is changed by
their reciprocal action into another which we wish to find ;
and in order to embrace the question in all its extent, l?t us
suppose that the movement may either change suddenly, or
; Vol. 30. No. 119.^/?n7 1808. O vary

S^Qf, On MacUnes In General.

vary by in&enslbilip degrees : finally, as fixed points or some
obstacles may be met with, let us consider them as they
really are,ii^;fi§i,9tj that is to say, as ordinary bodies of them-
selves,^ i^ali^ing ,pfirt of the system proposed, but firmly ar-
rested iu.the spot where they are placed.

XV. In order to. attain the solution of this problem, let
u^^fi/^t,of3^eurv;e, tlxat, all the parjti^^-oi;' the system being sup-
posed perfectly hard, i. e. incompressible and inextensible,
we may visibly, whatever it may be, regard it as composed
of an infinity of hard corpuscles, separated from each other
either by small incompressible rods, or by small inextensible
wjres;. for when two bodies strike, push, or tend in gcne-
rjj. to approach each- other without being able to doit, on
account of their impenetrability, we can conceive between
tl)e two a small incompressible rod, and suppose that the
njp.Vemj^pt^^ is,trau&miUed From the one to the other accord-
ing to this rod : and in the same way, if two bodies tend to
separate, we may conceive that the one is attached to the
other by a small inextensible wire, according to which the
movement is propagated : this being done, let us conjider
successively, the action of each of these small corpuscles upon
all those which are adjacent to it, i, e. let us examine two by
two all these small corpuscles separated from each other by a
small incompressible rod, or by a small inextensible wire,
and we shall sec what ought to result in the general system
of all these corpuscles. Let us name for this purpose,

77/ and m" The masses of the adjacent corpuscles.

V and V' The velocities they ought to have the follow-^
ing instant.

F' The action of m^^ upon m\ that is to say, the force or
quantity of movement which the first of these cor-
puscles imprt-sses upon the other.

F'' The reaciion of ?»' upon ni\

q[ and q' The angles formed by the directions of V and
F and by thJse of V' and F^'.

This being done, the real velocity of m' being V, this
velocity estimated in the direction of F will be \' cosine q*;
in the same manner the velocity of tt^' estimated in the
direction of V will be W^ cosine g". Therefore, since by

the

On Machines in General, 211

the second fundamental law bodies should go in company*
we shall have V cosine q' + V" cosine q" = 0 (A) : thus
by the first fundamental law, we shall also have F' V co-
sine q' + F" V" cosine q" t^ 0 (B) : for if m' and rti!' are
both moveable, it is clear, by this law, that we have F" = F";
therefore on account of the equation (A) we shall also have
the equation (B) ', anal if one of the two, 7n' for instance, be
fixed, or form part of an obstacle, we shall have V co-
sine ^' = o ; therefore on account of the equation (A) we
shall also have Y" cosine^' = 0^ therefore the equation
(B) will still take place : therefore this equation (B) is
true for all the corpuscles of the system taken two by two.
Imagining therefore a similar equation for all these bodies
taken in fact two by two, and adding tT)gether all these equa-
tions, or, what comes to the same »hing, the integral equa-
tion (B), we shajl have for the whole system,

s Y' V' cosine q' -{• s ¥' V" cosine ^" = o : that is to say,
the sum of the products of the quantities of movement
which are reciprocally impressed by the corpuscles separated
by each of the small inextensible wires or incompressible
rods; from these quantities, I say, each of them multiplied
by the velocity of the corpuscle on which it is impressed,
estimated in the direction of this force, is equal to zero.

This being done, abandoning the preceding denomina-
tions, let us name

The mass of each of the cc^rpuscles of the system - m

Its virtual velocity, i. e. that which it would assume
if it were free, ------- W

Its real velocity - - - - - - V

The velocity which it loses in such a manner that
\V is the result of V and of this velocity - - U

The force or quantity of movement which each of the
adjacent corpuscles impresses upon tti, and by the inter-
medium of which it evidently receives all the move-
ment that' is transmitted to it from the different parts
of the systQm, -- - - • - -F

The antvle comprehended between the directions
of W 'and> - - X

The angle comprehended betweea the directions of

WandU Y

0 2 Tbc

212 On Machines in General,

The angle comprehended between the directions of

V and U - Z

The angle comprehended between the directions of

V and F q

We shall therefore have for the whole system 5 F V co-
sine q = Of or sV F cosine ^ = 0 (C) : at present we
must observe that, the velocity of 7S before the reciprocal
action being \V, this velocity estimated in the direction
of V will be W cosine X ; therefore V— W cosine X is
the velocity gained by m in the direction of V: therefore m
(V — W cosine X) is the sum of the forces F which act
upon 7n, estimated each in the direction of V : therefore m
and V (V — W cosine X) is the same smn multiplied by V,
Now to each molecule a similar sum answers ; and further,
the sum total of all these particular sums is visibly for the
whole system ^ V F cosine q ; therefore s mY (V — W
cosme X) = s FV cosine q : adding to this equation the
equation (C), there comes 5 m V (V — W cosine X) = O
(D) ; but W resulting from V and U, it is clear that we
shall have W cosine X = V 4- U cosine Z : substituting
therefore this value of W cosine X in the equation (D), it
will be reduced to 5 m V U cosine Z = 0 (E) ; first funda^
mental equation.

XVI. Let us imagine that at the moment when the shock
is about to be given, the actual movement of the system is
at once destroyed, and that we make it take instead of it
successively two other arbitrary movements, but equal and
directly opposite to each other, i, e, let us make it set out
successively from its actual position, with two movements,
such that, in virtue of the second, each point of the system
has at the first instant a velocity equal and directly opposed
to that which it would have had in virtue of the first of these
movements: this being done, it is clear, 1st, That the
figure of the system being given, this may be done in an
infinity of different ways, and by operations purely geome-
trical ; this is the reason why I shall call these movements
geometrical movements ; i. e. that if a system of bodies sets
out from a given position with an arbitrary movement ^ but
7jet of such a nature that jt is possible to make it take another
?n every respect eqiial and directly opposite^ each of these

movementi.

On Machines in General, 213

movemejits will he named a geometrical movement *, 2dly, I
say that in virtue of this geometrical movement, the adja-
cent corpuscles, which may be regarded as being pushed by
a rod, or drawn by a wire, will not approach nor recede
from each othe.r at the first instant, i. e. at the first in-
stant of this geometrical movement the relative velocity
of these adjacent corpuscles will be nothing : in fact, it is
clear, in the first place, that if m be separated from an ad-
jacent corpuscle by an incompressible rod, it will not be
able to approach it ; and that if it be separated from it by
an inextensible wire, it will not be able to recede from it :
secondly, I say that if it be separated from it by an in-
compressible

♦ In order to disdnguish by a very simple example those movements
called geometrical from those which are not so, let us imagine two globes
which push each other, but in other respects free and disengaged from ever^
obstacle : let us impress upon these globes equal velocities, and moved in the
same direction according to the line of the centres ; — this movement is geomt'
trical, because the bodies could even be moved In a contrary direction with
the same velocity, as is evident : but let us now suppose that we impress upon
these bodies movements equal, axKl directed in the line of the centres, but
which, in place of being, as formerly, moved in the same direction, tend on
th« contrary to recede from each other ; these movements, although possible,
are not what I mean by geometrical movements ; because if we wished to make
each of these moveable powers to assume a velocity equal and contrary to
that which it receives in this first movement, we should be hindered fronj
doing so by the impenetrability of bodies.

In the same way if two bodies are attached to the extremities of an inex-
tensible wire, and if we make the system assume an arbitrary movement, but
so as that the distance of the two bodies may be constantly equal to the length
of the wire, this movement will be gcometricaly because the bodies may as-
sume a similar movement in quite a contrary direction ; but if these moveable
bodies approach to each other, the movement is not geometrical, because t]»«y
could not take a movement equal and contrary without receding from each
other; which is impossible on account of the inextensibility of the wire.

In general it is evident, that whatever be the figiire of the system and the
number of bodies, if we can make it assume a movement so as there should
result no change in the respective position of the bodies, this movement will
be geometrical ; but it does not follow from this that there is no other me-
thod of satisfying this condition, as we shall show from several examples.

Let us imagine an axle, to the wheel and cylinder of which are attached
weights suspended by cords : if we turn the machine in such a manner that
the weight attached to the wheel should descend from a height equal to its
circumference, while that of the cylinder will ascend from a height equal to
its circumference, this movement wiU be gFometricali because it is equally

0 3 possible

214 On Machines in General,

compressible rod, it cannot recede from it any more ;
for, if it receded, it is clear that in virtue of the equal and
directly opposite movement, which is also possible by hy-
pothesis, it would approach it ; which could not be on ac-
count of the inconipressibility of the rod : for the same,
reason finally it is obvious, that if it he a wire which sepa-
rates m from the adjacent corpuscle, it will not approach,
because then it would be possible to remove it by an equal
and directly opposite movement : now this cannot be, on
account of the inextensibility of the wire : therefore, what-
ever may be the geometrical movement impressed upon the

possible to make the weight attached to the cylinder descend from a height
equal to its circumference, while the weight attached to the wheel would
mount from an equal height to its circumference^ but if while we cause th?
weight attached to the wheel to descend from a height equal to its circumfe-
rence, wp should cause the weight attached to the cylinder to ascend from a
height greater than its circumference, the movement would not be ^cnmctricalf
because the equal and contrary movement would be visibly impossible.

If sevjral bodies be attached to the extremities of different wires united by
the other extremities to one and the same knot, and if we make the system
assume such a movement as that each of the bodies remains constantly re-
moved from the knot of one and the same quantity at t'le length of the wire
to which it is attached, this movement will be geometrical, even when the
different bodies approach to each other; but if some of them approach the
knot, the movement would not be geometrical, because, the wires being sup-r
posed to be inextensible, the equal and contrary movement would be visibly
impossible.

If two bodies are attached to the extremities of a wire into which is intro-
duced a moveable particle, it will be sufficient, in order that the movement
be geometrical, that the sura of the distances from the moveable particle to
each of the two other bodies is constantly equal to the length of the wire ; so
that if these two bodies are fixed, the moveable particle will not depart from
an elliptical curve.

If a body be moved by a curved surface, for instance, in the concavity of
a spherical shell, the movement will be geometrical, while the body will move
in a tangent form to the surface •, but if it be separated the movement will
cease to be geometrical, because the equal and contrary piovempnt is visibly
impossible.

Vrom all this it is evident, that although on giving to a system a. geometrical
movement, the different bodies of this system may be brought near to each
other, yet we may say that the adjacent corpuscles, considered two by two,
do not tend at the first instant cither to approach or recede, as I shall prove
at length in the text. Bodies therefore exercise no action upon each olher in
virtue of a similar movement : these movements are therefore absolutely in-
dependent of the rules of dynamics, and it is for this reason that I have called
them geometrical. "

system.

On Machines in GensraL ^515

system, the relative velocity of all these adjacent corpilstlfcs
which act upon each other^ taken two by two^ will be tid-
ihing at the rirst instant. This being granted, let us callow
the absolute velocity which m will have in the first rnstant,
in virtue of this geometrical movement, and z the angle coiii-
prehended between the directions of tc and U ; it is clclir
that the corpuscles m will not tend to approach or recede
from each other in virtue of the velocities 2/, if we su'ppose
them animated at the same time with these velocities u and
velocities U ; nor will they tend more to approach or recede
if animated with the mere velocities U : thcretbrc the re-
ciprocal action exercised among the different parts of the
system will be the same, whether each molecule be anima-
ted with the sino-|e velocitv U, or with the two velocities u
and U : but if each molecule was animated with the single
velocity U, it is plain that there would be equilibrium':
thus, if it was animated at once with the two velocities U
and ?/, or with a single velocity the result of both, U will
still be the velocity lost by tn ; and u will be the real velocity
after the reciprocal action : thus, by the same reasoning by
which we had the fundamental equation (E) we shall also
have srritiU cosine z = 0 (F) ; second fundamental equa-
tion.

It is very easy at present to resolve the problem which we
propose for the preceding equation necessarily taking place,
whatever be the value of u and its direction, provided the-
movement to which it refers be geometrical : it is clear that
by successively attributing to that indeterminate different
values and arbitrary directions, we shall obtain all the ne-
cessary equations among the unknown quantities, upon
which depends the solution of the problem and of quantities
either given or taken at pleasure.

XVII. In order to place this solution in the clearest light,
• it will be sutlicient to give an example of it.

Let us suppose therefore that tlie whole system is reduced
to an assemblage of bodies united to each other by inflexible
rods, in such a manner that all the parts of the system
should be forced always to preserve their same respective

0 4 positions;

•.fJL6 On Machines in General.

, positions; but that there is no fixed point or any obstacle;
. ,the equation (F) gives us the solution of this problem on
^attributing successively to 7i different values and directions.
|,, 1st. As the velocities 2/. are not subjected to any condi«
^lion, unless the movement of the system in virtue of which
.Ithe corpuscles m have these velocities be geometrical, it is
.jCvident that we can at first suppose all of them equal and pa-
,,Tfillel to one given line : then u being constant, or the same
ij^ith respect to all the points of the system, t]»e equation (F)
.will be reduced to s m U cosine 2: = 0; which informs us
that the sum of the forces lost by the reciprocal action of the
bodies in the aibitrary sense of u is null, and that conse-
quently that which remains is the same as if each body had
been free; this is a well-known principle,

Sdly. Let us now imagine that we make the whole system
turn round a given axis, so that each of the points will de-
scribe a circumference round this axis, and in a plane which
shall be perpendicular to it ; this movement is visibly geo-
metrical; therefore the equation (F) takes place: hut then
on calling R the distance from vi to the axis, it is clear that
we have 21 = AR'', A being the same for all the points ;
therefore the equation (F) is reduced to 5 w R U cosine
z — 0; that is to say, that the sum of the momenta of the
forces lost by the reciprocal action relatively to any axis is
null ; this is another well-known principle,

3dly. We might also attribute to u other values ; but this
would be useless, and might lead to equations already pon-
tained in the preceding; for we know that the latter are
sufficient for resolving the question, or at least fqr reducing
it to a matter cf pure geometry.

First Remark,
XVI IT. The object we propose by giving a geometrical
movement is to change the state of the system, without al-
tering however the reciprocal action of the bodies which
compose it, in order i hereby to procure relations between
these exercised and unknown forces and the arbitrary velo-
cities which bodies assume in virtue of these different geo-
metrical

On Machines in General. 217

metrical movements : but it must be remarked that there \^
a case where geometrical movements are not the only ones
which can answer the same purpose, and where some other
movements may be employed in the same way, in order to
extract from the general equation (F) determinate equations:
this happens when these other movements, without being
absolutely geometrical, become so, nevertheless, merely on
suppressing some of the small wires or rods we have sup-
posed to be interposed between the adjacent particles of the
system, at the time, I say, when these rods or wires supposed
to transmit the movement from one corpuscle to another,
transmitted none at all in fact ; i. e, when the tension of
some of these wires, or- the pressure of some of these rods,
is equal to zero ; for then by suppressing these wires or
rods, the tensions or pressures of which are null, we evi-
dently change nothing at all of the reciprocal action of the
bodies, and nevertheless it is possible that we may thereby
render the system susceptible of some geometrical move-
ments,which could not otherwise take place : there is nothing
therefore to prevent us from regarding these rods and wires
as annihilated, since they have no influence upon the state of
the system ; and as we consequently employ as geometrical
the movements which, without being so effectively, become
so nevertheless by this suppression.

Further, when two bodies are contiguous to each other,
it is evidently the same thing to suppress the small rod
which we have imagined 'to be interposed between two, to
hinder them from approaching, or to suppose that these
bodies are permeable to each other^ i. e. that they may be
penetrated as easily as the empty space is penetrated by all
bodiesf; whence it evidently follows, that in general, in any
gystem of bodies acting upon each other, immediately or by
wires and rods, i. e. by the intermedium of any machine,
if there be any wire, rod, or other part of the machine
which exercises no action upon bodies applied to it, i, e,
which may be annihilated without any change resulting in
the reciprocal action of these bodies, we shall be able to
treat as geometrical all the movements which, without
being so effectively, would becopae sq by this suppression,

iu

5V8 On Machines in General,

in the same way as those which would become so also, re-
garding as freely perTneable to each other, those of the
bodies among which no pressure is exercised, although they
Are adjacent. l>ie,iof]owing, however, shows the utility of
this observation :

If, when we undertake the solution of any piobleni, we
know beforehand that a certain part of the machine does
not exercise any actioa upon the other parts of the system,
we shall be able to suppose that this part of the machine is
totally annihilated, and ascertain the movement of the sy*
^tem according to this hypothesis, i. e. by treating as geo-
metrical all the movenw.nts which would really become so
by this supposiiion ; and in the same way, if one of the given
conditit)ns of the problem is, that certain adjacent bodies d«
not exercise any p e^^sure upon each other, we shall express
this condition by regarc^ng these two bodies as permeable
to each other, i, e. by treating as geometrical the move-
ments which would in fact become so by this supposition.

But if it happens that we arc ignorant whether this pres-
sure be real or null, wc must ascertain the movement of
the system, by first supposing the one or the other at plea-
6ure : we shall suppose therefore, for example, that this'
pressure is real : then, if on inquiring, according to this
hypothesis, the value of this pressure, we find it real and
positive, we shall conclude that the hypothesis is legitimate,
and the exact result; or else we shall be assured that the
pressure in question is null, and that we may consequent-
Iv treat as geometrical^ motions which would become so
in fact, iF the two bodies in question were freely permeable
to each other.

Further, if there was a machine in the system, a wire for
example, and that we were ignorant if the tension of this
wire is null or real, we might make the calculation by at
first supposing that there really is tension ; then, if we find
for the value of this tension a real and positive quantity, we
shall conclude that the supposition is legitimate, and that
the result is exact; or else, we must recommence the cal-
culation, setting out from the conh-ary supposiiion, i. e,
guppGsing that the tension of the wirc is equal to zero;

. which

(

On Machines in GeneraL 21 D

xvbich will be done by supposing the wire annihilated, i. e.
by treating as geometrical the motions which would be so
effectively if the wire in question did not exist.

From this it follows, that in order to extract in each par-
ticuJar case from the general equation (F) all the determi-
nate equations which it can give, we must first make the
system assume all the geometrical movements of which it is
susceptible; secondly, to treat also as such all those which
would become so by suppressing some machine or part of a
machine, the action of which upon the rest of the system
is null, or by regarding as permeable to each other, the
bodies among which, although adjacent, no pressure is ex-
ercised. 3dly. In the last place, if we are in doubt whether
a certain wire, rod, or any part of the machine has or has
rot a real action upon the other parts of the system, or that
there was a real pressure between two adjacent bodies, we
must first clear up this doubt, by supposing the thing in
question as we have above explained it, and by treating as
• geometrical the movements which these suppositions shall
have discovered as being capable of being taken for such.

According to this remark, it seems proper therefore to
extend the name of geometrical, to all the movements,
which, without being so effectively, become so on suppress-
ing some machine or part of a machine which has no in-
fluence upon the state of the system, and on regarding also
as perfectly permeable to each other, bodies in contact,
without any pressure being exercised among them, i. e,
without there being any ihing except a simple juxtaposi-
.tion : thus we shall presently comprehend all these move-
ments, under the title of geometrical movements, since in
tact they are equally well determined by operations purely
geometrical, and are employed in the same way for extract-
ing from the general equation (F) determinate equations,
^whilc the general and exclusive property* of these move-
ments

* It Is evident that this property belpngs successively to the movements
-'vvhlch I here cali geometrical, and that it woyld consequeutly be a very false
idea of them to regard them as movements simply possible, i.e. compatible
with the iiDpen«trability of matter: for, suppcsi rg, lor instance, that all the

syatena

930 On Machines hi General,

ittents is ta change the state of the system, without altering
the reciprocal aptioii of the bodies which compose it. To
leave, however, some distinction between them, we may
Call the first ahsolute geometrical movemciitSy and the others
geoinetrkal movements hy supposition: but when I speak
simply of geometrical movements, without otherwise de-
signing them, I shall imply both indifferently.

This being done, — since we have explained how we may
determine, without the assistance of any mechanical prin-
ciple, all the geometrical movements of which a given sy-
stem is susceptible, it follows that the general problem which
we proposed is entirely reduced by the general equation (F)
to operations purely geometrical and analytical : we must,
however, observe, that it is not sufficient to attribute to the
arhitrarles u different values, but we must also attribute to
them different relations or directions; for, if we are con-
tented to attrii)ute different values to them without changing
any thing in the relations or directions, we should obtain
different equations, quite true and correct, but which would
be evidently reduced to the same on multiplying them by
different constants.

Second Remark,

XIX. As we are only speaking of hard bodies here, it is
clear that among the different values which we may attri-
bute to u, the velocity V is itself comprehended ; i, e. that
the real movement of the system is itself one of the geome-
trical movements of which it is susceptible : the first equa-
tion (E) is therefore contained in the indeterminate equa-
tion (F), and consequently we may reduce to this single
equation (F) all the laws of equilibrium and of movement
in hard bodies.

Now we have seen, that this equation is nothing else
than the first (E), to which we have succeeded in giving

system be reduced to two adjacent globes, and pushing each other, i t is clear,
that if we force these bodies to separate or to move in a direction contrary to
each other, this movement will not be impossible, but that at the same tiqie
bodies cannot assume it without ceasing to act upon each other. This move-
ment, therefore, is not proper for attaining the object proposed, which is to
(ph^inge nothing in the reciprocal action of bodies.

_ . n-iorc

OnJinisUng the Inside of Palaces, V^ ^ iH

more extension by means of the geometrical movements;
tut as we shall soon see (XXIV) the analogy of this equa-
tion (E) with the principle of the preservation of the moving
powers in the shock of perfectly elastic bodies becomes
Striking by a slight transformation ; and we shall see
(XXVf), that in fact it is nothing else than this principle
itself* transferred to hard bodies, with the modification re*
quired by the diifcrcnt nature of these bodies : it is therefone
this preservation of moving powers which will serve, as we
have premised, as a basis to the whole of our theory of
machines, whether at rest or in motion.

According to these remarks we shall briefly recapitulate
the solution of the preceding problem, in order to bhow at
one glance the course of the operations indicated.

[To be contiuued.3

XLIV. Processes employed fm' finishing the Inside of the
Palaces of the Native Princes in^^^^ne Parts of the East
Indies^, A j,v;| y^

X HE principal workman employed by colonel Clo^se in re-
pairing the palace in the Laul Bang, gave me the following
account of the processes used for finishing the inside of the
palaces at Seringapatam,

At first sight, one would imagine that much gilding is
used in the ornaments ; but, in truths not a grain of gold is
employed. The workmen use a paper covered with false
gilding. This they tut into the shape of flowers, and paste
these on the walls or columns. The interstices are filled up
with oil colours, which are all of European preparation. —
The manner of making this false gilded paper is as follows :

Take any quantity of lead, and beat it with a hammer
into leaves, as thin as possible. To twenty^four parts of
these leaves add three parts of English glue, dissolved in
water, and beat them together with a hammer, till they be

* From Buchannan'» Journey, from Madras thvovgh ike Mysore^ Canara, '
and MalalaT,

thoroughly

f22 O71 finishing the Inside of East Indian Palaces,

thoroughly united, which requires the labour of two persons
for a whole day. The mass is then cut into small cakes,
and dried in the shade. These cakes can, at any timt.', be
dissolved in water, and spread thin with a hair brush on
common writing paper. The paper (when dry) must be
put on a smooth plank, and rubbed with a polished stone
till it acquire a complete metallic lustre. The edges of' th«
paper are then pasted down on the board, and the metallic
surface is rubbed with the palm of the hand, which is
smeared with an oil called giirnUy and then exposed to the
sun. On the two following days the same operation is re-
peated ; when the paper acquires a metallic yellow colour,
which, however, more resembles the hue of brass than
that of gold.

Tht gurna o\\ is prepared as follows: — Take three quar-
ters of a maund (about 18 lib.) of linseed oil, half a maund
(12 lib.) of the size called cfmnderasny and a quarter of a
maund (6 lib.) oimusamhra, or aloes prepared in the country.
Boil the oil for two hours in a brass pot. Bruise the mit-
sambra'y and, having put it into the oil, boil them for four
hours more. Another pot having been made red-hot, the
cfmnderasu is to be put into it, and will immediately melt.
Take a third pot, and, having tied a cloth over its mouth,
strain into it the oil an.l musambra : these must be kept in
H gentle heat, and the chunderasu added to them gradually.
The oil must be strained again ; and it is then fit for use.

The chunderam is prepared from the milky juice of any of
the following trees : ( flcus glomerata Roxb.), goni^ (a tree
\\\\\q\\ \ c->x\\ ficus gonki) , Bayla, Bayvina, Gabali, &c. It
is therefore an elastic gum.

The oil used for painting consists of two parts of linseed,
and one part of chunderasu.

In white-washing their walls, over the chunam, or lime
plaster, the workmen of Seringapatam first give a thin coat
of S7iday, or fine clay ; which is mixed with size, and put
on with a hair brush. They next give a coat of whitening,
made of powdere'd lalapum or pot-stone ; and then finish
-with a coat composed of eight parts of ahracum, of mica,
oae part of powdered lalapum, and one of size.

The

On the Analyses of the Chromate of Irony &c, 223

The abracum is prepared from white mica,, by repeated
grindings, the finer particles being removed iior use by wash-
ing them from the grosser parts.

The wall, when finished in this manner, shines hke the
scales of a fish ; and when the room is lighted has a splendid
appearance: but in the day-time, the wall washed with the
powdered potstone alone, in my opinion, looks better ihaa
when waslied with either quick-lime or mica.

XLV. Notice ztpon the jlvahjses of the ChrtMate of Irouy
and. iLpon the Fariety of ike Epidote called Zmjsile. By
Ji. Haoy*.

-iVI. Laugier has published in a former number of these
Aiinales t, the result of the analysis he made of the chro-
mate of iron of Siberia, and this result was similar to that
obtained by M. Vauquelin, when examining the chromate
of iron discovered by M. Pontier in the department o^*
Var. M, Klaproth lately repeated the analysis of the sanie
substance upon a piece which came from Krieglach, in
Styria ; and his results having been communicated to M^
Laugier, we now insert it, as presenting a confirma,tion o£
the two preceding analyses.

KLAPROTH. LAUGIER. rAUQUELIX.

Chromate of Iron of Styria. • Chromate of Siberia. Chromate of Van

Oxide of chrome 55'5 53 43

Oxide of iron - - 33 34 34'T

Alumina - - - ^ . H 0Q.3.

Silex - - - - 2 1 2

O

0

Waste by roasting * 2 0

Loss - - _

55-5
33

2
2

1-5

100 100 100

We find in a subsequent number the result of another
analysis made by M. Laugier upon a grayish substance-

• From Annales du Musmm d^Uisioire, tome ix. p, 103.
f See Phil. Mag, vol. xriv. p. 3

brought

i24 On the Analyses of the Chromate of Iron, ^c.

brought from the Valais, which I recognised from its struc-
ture and physical properties to be a variety of the epidote'/
although it differed in its external characters from the cry-
stals of this species hitherto observed. M. Laugier found
that the respective quantities and qualities of its component
principles were the same as in the epidote of Arendal, and
in that of France, analysed by M. Vauquelin and M. Des-
costils.

The same variety also exists in Carinthia and in some
of the neighbouring countries ; and M. Werner has since
given the name of zoysite to it in honour of barofi Zoys.
The distinction which M. Werner establishes between this
substance and our epidote is in some measure a consequence
of the nomenclature adopted by this celebrated naturalist ;
for he gives to the epidote ihe name of Pistazite (Pistachio
stone) because it is g'^nerally of a more or less deep green.
Now this name seems to exclude the zoysitc, the colour of
which is gray, brown, or brownish yellow, but never green ;
at least it is so in those specimens we have seen.

M. Laugier has been informed that Messrs. Klaproth and
Bucholz have recently analysed the zoysite ; and the follow-
ing are their results, compared with those of the French
chemist.

KLAPROTH. LAUGIER. BUCHOLZ.

Gray Epidote, said to be The same Substance. The same Substance.
Zoysite.

Silex - - - - 45 37 40*25

Alumine - - - 29 • ^Q'Q 30*25

Lime - - - - 21 • 20 22*5

Oxide of iron - 3 13 4*5

Oxide of manganese o 0-6 0*0

Water - - - - o 1*8 2

Loss - - - - 2 1 0-5

loa 100 100

If wc compare these three results either with each other

or with the others which have for their objects the epidotes

of Norway and France ; and if on the one hand wc consider

tiie- agreement which exists, between chemistry and the

geometry

On drying Articles of Manufacture, <^c. 225

geometry of crystals, we shall find the most convincing proofs
that the zoysite should be joined to the epidote, like the
mineral of Norway, which a deceitful indication of its cha-
racters had made to be placed in a particular sj)ecies under
the names of arendalite and akanticonc.

XLVr. On drying Articles of Manufacture, and heating
Buildings, hij Steam, By R. Buchannan, Esq,y Civil
Engineer, Glasgow.

To Mr. Tillocfu

SLRf

JVxANY additional facts with regard to heating by steam
have lately been ascertained in this neighbourhood, and its
application to various processes in manufactures continues
to increase. Mr. Richard Gillespie is highly pleased with
its effects upon copper-plate callica-printing at his works,
as also for heating his calenders* For this last purpose, and
to warm his warehouse and counting-house, the steam is
conve}Td to a distance of above ninety-three yards.

Steam was, I believe, tried many years ago at Leeds,
for drying goods, as a substitute for stoves ; but for some
reason, of which I am ignorant, was abandoned. Mr.
Lounds, at Paisley, however, has for a considerable time
used it with gieat success in drying fine muslins. Messrs.
Leys, Mason and Co. now also use it at their bleaching
works, at Aberdeen.

Some kinds of muslins have for several years been dried
by being rolled round cylinders of tin plate filled with steam,
but I do not here allude to that mode.

For drying of dyed yarn and pullicates, (a kind of co-
loured chequed cotton handkerchiefs,) a higher temperature
than for fine muslin is required. I am glad, however, to
Lave it in my power to say, that Messrs. Muir, Brown,
and Co., at their dyeing and bleaching works here, have
found steam to answer those purposes much better than the
usual mode by stoves. Mr. Muir informs me, that, al-
though they formerly gave out their pullicates tol)e bleached

Vol. 30. No. 119. v%// isoe. P " to

^26 On tJie Uses of Leaves and Pru?ii?igs of Vines,

to some of the local bleachers in this part of the country,
they never had their colours in the same perfection which
they now have, and which they attribute entirely to the
superior effect of the steam.

It occurs to me, that steam might be appHcd for warming
buildings in I-.ondon, in many instances, with great advan-
tage. For instance, the bed-rooms of large inns and hotels ;
as also large warehouses or shops, where a number of neigh-
bouring buildings might be warmed from one boiler, which
would save much in attendance and fuel, as well as in the
cost of the apparatus. It is also well adapted to the pur-
pose of warming churches, hospitals, and other large pub-
lic buildings. I am, sir, your most obedient servant,

Robertson Buchannan.

Glasgow, ,

April 2, 1808.

XLVII. On the ceconomlcal Uses to which the Leaves and.
Prunifigs of Fines may le applied in tins Country,

To Mr. Tilloch,

SIR,

X* ROM experiments which I have made, I find that, on
being dried, which should be done in the shade, and infused
in a tea-pot, the leaves of the vine make an excellent sub-
stitute for tea. I have also found that, on being cut small,
bruised, and put into a vat., or mashing-tub, and boiling water
poured on them, in the same way as is done with malt, the
prunings of the vine produce a liquor of a fine vinous quali-
ty ; which, on being fermented, makes a very fine beve-
rage, either strong or weak, as yoii please; and, on being
distilled, produces an excellent spirit of the nature of brandy.
In the course of my experiments I found that the fer-
mented liquor from the prunings, particularly the tendril$>
when allowed to pass the vinous and to run into the acctoua
fermentation^ makes uncommonly fine vinegar. If not in-
tended to be distilled soon after they are lopped off, or if it
should not be convenient to do so at the time, they should

be

Observations on the neiv celestial Bodyy ^c* 227

be dried in the shade. When intended to be used, an ex-
tract should be made with hot water, as in the common
process for distilling from grain.

As this is the season when the vine puts forth its leaves,,
and many thousand cart-loads of the prunings, where ther^
are not goats to eat them, are yearly thrown away as user
less, your stating the above in your highly, interesting and
useful Magazine may be of use to many of your readers,
and to the public in general. I am, sir,

your constant reader,

London, JA^fES HsALL.

April 8,. 1808,

XLVni. Observations on the Nature of the new celestial
Body discovered by Dr, Olbers ; and of the Comet which
was expected to appear last January in its Return from the
Sun, By William Herschel, L.L,D F.R.S, *

JL HE late discovery of an additiortal body belonging to the.
solar system, by Dr. Olbers, having been communicated to
me the 20th of April, an event of such consequence en-
gaged my immediate attention. In the evening of the same
day I tried to discover its situation by the information I had
obtained of its motion ; but the brightness of the moon,
which was near the full, and at no great distance from the
object for which I looked, would not permit a star of even
the 5th magnitude to be seen ; and it was not till the 24th
that a tolerable view could be obtained of that space of the
heavens in which our new wanderer was pursuing its hither-,
to unknown path.

As soon as I found that small stars might be perceived, I
made several delineations of certain telescopic constellations,
the first of which was as represented in figure 1, and I fixed
upon the star A, as m6st likely, from its expected situatipn
and brightness, to be the one I was looking for. The stars
ia this figure, as well as in all the other delineations I Ji§d

• From Philosophical Tr9ns^ctip,ns,Jf|^r, 1J(07« P^^^

P2 . > -c/ made.

^4b Ohervattofis on the new celestial Body

made, were carefully examined with several magnifyiilg
powers, that in case any one of them should hereaiicr ap-
pear to have been the lately discovered object, I might not
lose the opportunity of an early acquaintance with its con-
.dition. An observation of the star marked A, in parti-
cular, was made with a very distinct magnifying power of
46o, and says, that it had nothing in its appearance that
differed from what we see in other stars of the same size ;
indeed Dr. Olbers, by mentioning in the communication
which I received, that with such magnifying powers as he
could use it was not not to be distinguished from a fixed
star*, had already prepared me to expect the newly dis-
covered heavenly body to be a valuable addition to our in-
creasing catalogue of asteroids.

The 25th of April 1 looked over my delineations of the
preceding evening, and found no material difference in the
situation of the stars I had marked for examination ; and in
addition to them new asterisms were prepared, but on ac-
count of the retarded motion of the new star, which was
drawing towards a period of its retrogradation, the small
change of its situation was not sufficiently marked to be
readily perceived the next day when these asterisms were
again examined, which it is well known can only be done
with night-glasses of a very low magnifying power.

A long interruption of bad weather would not permit any
reofular examination of the situation of small stars : and it
was only when I had obtained a more precise information
from the astronomer royal, v^ho, by means of fixed in-
struments, was already in possession of the place and rate
of motion of the new star, that 1 could direct my telescope
with greater accuracy by an applcaition of higher magni-
fying powers. My observations on the nature of this se-
cond new star discovered by Dr. Olbers arc as follow.

April 24. This day, as we have already seen, the new
celestial object was examined with a high power; and since

* Der neue planet zeigt sich als ein stern zwischen der 5ten und Gten
grcisse und Ut im fernrohr, wenigsten mit den vergrisserungen die ich^au-
wsnden kann, von cinen fixstern nicht zu unterschelden.

' discoveredji/ Dr, oilers, &c, 229.

a magnifier of 460 would not show it to be different from,
the stars of an equal apparent brightness, its diameter must
be extremely small, and we may reasonably Expect it to be
an asteroid.

May 21. With a double eye-piece magnifying only 75
times the supposed asteroid A makes a right-angled triangle
with two small stars a h. See fig. 2.

^..With a very distinct magnifier of 460 there is noj^%
pearance of any planetary disk. ; i, ,^

May 22. The new star has mowd away from a hy ,^i>d is
now situated as in fig. 3. The star A of figure 1 is no
longer in the place where I observed it the 24th of April,
and was therefore the asteroid. I examined it now with
gradually increased magnifying powers, and the air being
remarkably clear, J saw it very distinctly with 460,, 577,
and 636. On comparing its appearance with these powers
alternately to. that of equal stars, among which was the
4'63d of Bode's catalogue of the stars in the Lion of the
7th magnitude, I could not find any difference in the visible
bize of their disks.

By the estimations of the distances of double stars, con-
tained in the first and second classes of the catalogues I have
given of them, it will be seen that I have always considered
every star as having a visible, though spurious, disk or
diameter : and in a late paper 1 have entered at large into
the method of delecting real disks from spurious ones : it
may therefore be supposed that T proceeded now with Vesta
(which name I understand Dr. Olbers has given the aste-
roid), as 1 did before in the investigation of the magnitudes
of Ceres, Pallas, and Juno.

,- The same telescopes, the same comparative vaews, by
>yhich the smallness of the latter three had been proved,
convinced me now that I had before me a similar fourth
celestial body.

, The disk of the asteroid wliich I saw was clear, well de-
fined, and free from nebulosity. At the first view I was
inclined to believe it a real one; and the Georgian planet
being conveniently situated, so that a telescope might with-

P 3 out

230 Olservations on the new celestial Body

6ut loss of time be turned alternately either to this or to the
Asteroid, I found that the disk of the latter, if it were real,
would he about one-sixth of the former, when viewed with
a magnifying power of 460. The spurious nature of the
^steroidal disk, however, was soon manifested by an in-
crease of the magnifying power, which would not propor^
tionally increase its diameter as it increased that of the
planet ; and a real diek of the asteroid still remains unseen
with a power of 636.

May 23. The new star has advanced, and its motioti i$
direct; its situation with respect to the two small stars a b,
is given in figure 4.

Its apparent disk with a magnifier of 460 is about 5- of
6-tenths of a second ; but this is evidently a spurious ap*
pearance, because higher powers destroy the proportion il
bears to a real disk when equally magnified. The air is not
sufficiently pure this evening to use large telescopes.

May 24* With a magnifying power of 577 I compared
the appearance of the Georgian planet to that of the asteroid,
and with this power the diameter of the visible disk of the
latter was about one 9th or 10th part of the former. The
apparent disk of the small star near /3 Leonis, which has
been mentioned bpfore, had an equal comparativ^e magni-
tude, and probably the disks of the asteroid and of the stat
it resembled are equally spurious.

The 20 feet reflector, with many different magnifying
powers, gave still the same result; and being already con»
vinced of the inipossibility, in the present situation of the
asteroid, which is above two months past the ojiposition, to
obtain a better view of its diameter, I used this instrument
chiefly to ascertain whether, any nebulosity or atmosphere
might be seen about it. Fc^r this purpose the valuable quan-
tity of light collected by an aperture of 1 ST inches directly
received by an eye-glas> of ihe fropt-view without a seconcj
reflection, proved of eminent use, and gave me the diameter
of this asteroid entirely free from all nebulous or atmospheric
appearances.

Tlie result of these observations is, that we now are in

posgessipi^

discovered lij Dr. Olbers, &c. 231

possession of a formerly unknown species of celestial bodies,
which, by their smallness and considerable deviation from
the path in which the planets move, are in no danger of
disturbing, or being disturbed by them ; and the great suc-
cess that has already attended the pursuit of the celebrated
discoverers of Ceres, Pallas, Juno, and Vesta, will induce
us to hope that some further light may soon be thrown upofi
this new and most interesting branch of astronomy.

Observations of the expected Comet.
The CG_met which has been seen descending to the sun,
and from the motion of which it was concluded that we
should probably see it again on its return from the perihelion,
was expected to make its reappearance about the middle of
last January, near the southern parts of the constellation of
the Whale.

January 27. Towards the evening, on my return from
Bath, where I had been a few days, I gave my sister Ca-
rolina the place where this comet might be looked for, and
between flying clouds, the same evening about 6^^ 49' she
saw it just long enou2:h to make a short sketch of its situa-
tion.

January 31 . Clouds having obscured the sky till this time,
I obtained a transitory view of the comet, and perceived
that it was within a few degrees of the place which had been
assigned to it; the unfavourable state of the atmosphere,
however, would not permit the use of any instrument pro-
per for examining it minutely.

There will be no occasion for my giving a more particular
account of its place, than that it was very near the elec-
trometer of the constellation, which in Mr. Bode's maps is
taWed inac/tina elect rica ; the only intention I had in look^
ing for it, being to make a few observations upon its physi-
cal condition.

February 1. The comet had moved but very little from
the place where it was last night ; and as the air was pretty
clear, I used a 10- feet reflector with a low power to ex-
amine it. There was no visible nucleus, nor did the light
which is called the coma increase suddenly towards the cen-
tre.

232 An Account of a Shotuer of Meteoric Stones,

tre, but was of an irregular round form, and with this low
power extended to about 5, 6, or 7 minutes in diameter.
When I magnified 109 times it was considerably reduced in
size, which plainly indicated that a further increase of mag*
nilying power would be of no service for discovering a nu-
cleus. On account of cloudy weather I never had ^n op^
portunity of seeing ihe comet afterwards.

When I compare these observations with my former ones
of 13 other telescopic comets, I find that out of the 16 which
J have ckamimcd, 14 have been without kny visible solid
body in their centre, and that the other two had a very ill
defined small central light, which might perhaps be called a
nucleus, but did not deserve the name of a disk.

XLIX. An Account of a remarkable Shower of Metewic
Stones, at IVeston in America. By Mr. Silliman,
Professor of Chemisti-y , and iVfr. Kingsi^ey, Professor
of Languages^ in Yale College^,

Yale College, Dec. 2G, 1807.

.As imperfect and erroneous accounts of the late phaeno-r
menon at Weston are finding their way into circulation,
we take the liberty of enclosing for publication the result
of an investigation into the circumstances and evidence of
the event referred to, which we have made on the ground
•where it happened. That we may not interrupt our narra-
tion by repeating the observation wherever it is applicable,
we may remark, once for all, that we visited and carefully
examined every spot where the stones had been ascertain-
ed to have fallen, and several places where they had been
only suspected without any discovery; that we obtained
specimens of every stone-^ conversed with all the principal
original witnesses ; spent several days in the investigation,
and were, at the time, the only persons who had explored
the whole ground.

Benjamin Silliman,
James L. Kingsley.

^ Conimunlcatedbv the right hon. Charles Grevillc, F.R.S, &c.

Tlie

An Account of a Shoiver of Meteoric Stones. 233

The meteor which has so recently excited alarm "in many,
and astonishment in all, first made its appearance in Wes^
ton, about a quarter or half past six o'clock, A. M., on
Monday the 1 4th instant (Dec. 1807). The morning was
somewhat cloudy ; the clouds were dispersed in unequal
masses, being in some places thick and opaque, in others
light, fleecy, and partially transparent ; while spots of un-
clouded sky appeared here and there among them. Along
the northern part of the horizon, a space of 10 or 13 de-
grees was perfectly clear. The day had merely dawned, and
there was little or no light, except from the moon, which
was just setting. Judge Wheeler, to whose intelligence and
observation, apparently uninfluenced by fear or imagination,
we are indebted for the substance of this part of our account,
was passing through the enclosure adjoining his house,
with lu§ face to the north, and his eyes on the ground,
when a sudden flash, occasioned by the transition of a lu*
minous body across the northern margin of clear sky, illu-
minated every object, and caused him to look up. He im-
mediately discovered a globe of fire, just then passing be-
hind the first cloud, which was very dark, and obscured,
although it did not entirely hide the meteor.

In this situation its appearance was distinct, and well
defined, like that of the sun seen through a mist. Jt rose
from the north, and proceeded in a direction nearly per-
pendicular to the horizon, but inclining, by a very small
angle, to the west, and deviating a little from the plane of a
great circle, but in pretty large curves, sometimes on one
side of the plane, and sometimes on the other, but never
making an angle with it of more than 4 or 5 degrees. It
appeared about one half or two thirds the diameter of the
full moon. This description of its apparent magnitude is
vague, but it was impossible to ascertain what angle it sub-
tended. Its progress was not so rapid as that of common
meteors and shooting stars. When it passed behind the
thinner clouds, it appeared brighter than before : and when
it passed the spots of clear sky it flashed with a vivid light,
* yet not so intense as the lightning in a thunder- storm, "but
6 ' rather

234 j4n Account of a Shower of Meteoric Stones,

rather like what is commonly called heat lightning. Its
surface was apparently convex.

Where it was not too much obscured by thick clouds, a
conical train oF paler light was seen to attend it, waving,
and in length about 10 or 12 diameters of the body. In
the clear sky a brisk scintillation was observed about the
body of the meteor, like that of a burning firebrand carried
against the wind.

It disappeared about 1.5 degrees short of the zenith, and
about the same number of decrees west of the meridian. It
did not vanish instantaneously, but grew, pretty rapidly,
fainter and fainter, as a red-hot cannon ball would do, if
cooling in the dark, only with much more rapidity.

There was no peculiar smell in the atmosphere, nor were
rfny luminous masses seen to separate from the bodv. I'he
whole period between its first appearance and total extinc^
tion was estimated at about 30 seconds..

About 30 or 40 seconds after this, three loud and disthict
reports, like those of a four-pounder, near at hand, were
heard. They succeeded each other with as nuich rapidity
as was consistent with distinctness, and^ all together, did
not occupy three seconds. Then followed a rapid succession
of reports less loud, and running into each other, so as to
produce a continued ruitibling, like that of Jl cannon ball
rolling over a Hoor, sometimes louder and at other times
fainter; some compared it to the noise of a waggon, running
rapidly down a long and stony hill ; or- to a volley of mus-*-
quetry, protracted into wh.it is called, in military language^
2. running jire. This noise continued about as iotig as the
bbdy was in rising, and died away, apparently in the direc-
tion from which the meteor came.

The accounts of others corresponded substantially with
this. Time was differently estimated by difiVrent people>
but the variation was not material. Some augmented the
number of Joud reports, and terror and imagination seem,
jti various instances, to have magnified every circumstance
of the phaeriomenon.
The Only thing which seemed of any importance beyond

this

An Account of a Shower of Meteoric Stones, 235

this statement, was derived from Mr. Elihu Staples, who
said, that when the meteor disappeared, there were appa-
rently three successive eflbrts or leaps of the fire-hall, which
grew more dim at every throe, and disappeared with the
last.

Such were the sensible phaenomena which attended this
meteor. We purposely avoid descrihing the appearances
which it assumed in other places, leaving this task to others
who have the means of performing it more accurately ;
while we proceed to detail the consequences which followed
Ihe explosions and apparent extinction of this luminary.

We allude to the fall of a number of masses of stone in
several places, principally within the town of Weston. The
jplaces which had been well ascertained at the period of our
investigation, were six. The most remote were about 9 or
10 miles distant from each other, in a line differing little
from the course of the meteor. It is therefore probable that
the successive masses fell in this order, the most northerly
first, and the most southerly last. We think we are able
to point out three principal places where stones have fallen,
corresponding with the thrte loud caimon-like reports, and
with the three leaps of the meteor observed by Mr. Staples.
There were some circumstances common to all th^ cases.
There was in every instance, immediately after the explo-
sions had ceased, a loud whizzing or roaring noise in the
xiir, observed at all the places, and, so far as was ascertained,
at the moment of the fall. It excited in some the idea of a
tornado ; in others, of a large cannon-shot in rapid motion ;
and it filled all with astonishment and apprthension of som6
impending catastrophe. In every instance immediately after
this was heard a sudden and abrupt noise, like that of a
ponderous body striking the ground in its fall. Excepting
one, the stones were more or less broken. The most inj-
portant circumstances of the particular cases were as fol-
low :

}. The most northerly fall was within the limits of Hunt-
ington, on th.e border of Weston, about 40 or 50 rods east
bf the great road from Bridgeport to Newtown, in a cross
tba(ll. and contiguous to the house of Mr. Merwin Burr.

Mr. Burr

S3<5 jinAcvouniqfaShowerqfMeleorieS(o?W5.

Mr. Burr wa;^ standing in the roatl, in front of his house,
when the stone fell. The noise produced by its collision
villi a rock of granite, on which it struck, was very loud.
Mr. Burr was within 50 feet, and immediately searched for
the body, but, it being still dark, he did not lind it till half
auhour after. By the fall, some of it was reduced to i)owder,
and the rest of it was broken into very small fragments,
which v^'cre thrown around to the distance of 20 or 30 feet^
The granite rock was stained at the place of contact with a
deep lead colour. The largest fragment which remained
did not exceed the size of a goose-egg, and this Mr. Burr
found to be still warm to his hand. There was reason to
concKide from all the circumstances, that this stone must
hare weijxhed about tw^entv or twenty-five pounds.

Wr. Burr had a strong impression that another stone fell
in an adjoining field, and it wasi confidently believed that a
large mas*^ had fallen into a neighbouring swamp, but nei-
ther of these had been found. It is probable that the stone
whose fall has now been described, togelher with any other
masses which may have fallen at the same time, was thrown
froni the meteor at the first explosion.

S, The masses projected at the second explosion seem to
have fallen principally at and in the vicinity of Mr. William
Princess, in Weston, distant, about five miles, in a southerly
direction, from Mr. Burr's. Mr. Prince and family were
still in bed, when thei/ heard a nnise like ike fall of a very
hearty lodyy immediately after the explosions. I'hey formed
TarioHS unsatisfactory conjectures concerning the cause—r
nor did even a fresh hole made through the turf in the door-
yard, about twenty-five feet from the house, lead to any
conception^ of the ca\isc, or induce any other inquiry than
.why a new post-hole should have been dug where there was
no use for it. So far we?e this family from cQuceiving of
the possibility of such an event as stones falling from the
clouds. They had indeed formed a vague conjecture that
the hole might have been made by lightniug, but would
probably have paid no further attention to the circumstance,
had ibey not heard, in the course of the day, that stones
had fallen th^t n^orning in other parts, of the town. Thi^

induced

^n .Account bf.a Shoucr of Meteoric Stone£y. ii3.7'?

iiKiLicecl them, towards evenings to search the hok \i\ the
yard, where they ioiiiul a stone buried in the lootsc earth-
which had fallen in upon it. It was two feet from the sur-
face— the hole was about twelve inches in diameter; and as
the earth was soft and nearly free from stones, the mass had
sustained little injury, only a few small fragments having
been detached by the shock. The weight of this stone was
about thirty-five pounds. From the descriptions which wc
have heard, it must have been a noble specimen, aiid men
of science will not cease to deplore that so rare a treasure
should have been immediately broken in pieces. All that
remained unbroken of this noble mass, was a piece of twelve
pounds weight, since purchased by Isaac ikonson, esq., of
Greenfield, with the liberal view of presenting it to some
public institution.

Six days after, another mass was disco^^ered, halFamile
north-west from Mr. Prince's. The search was induced by
the confident persuasion of the neighbours that they heard'
it fall near the spot where it was actually found buried in
the earth, weighing from seven to ten pounds. It was
found by Gideon Hall and Isaac Fairchild. It was in small
fragments, having fallen on a globular detached mass of
gneiss rock, which it split in two^ and by which it was it-
self shivered to pieces.

The same men informed us that they supected another
stone had fallen in the vicinity, as the report had been di-
stinctly heard and could be referred to a particular region
somewhat to the east. Keturning to the place after an ex-
cursion of a few hours to another part of the town, we were
gratified to find the conjecture verified, by the actual dis-
covery of a mass of thirteen pounds weight, which had
fallen half a mile to the north-east of Mr. Prince's. Having
fallen in a ploughed field, without coming into contact with
a rock, it was broken only into two principal pieces, one of
which, possessing all the characters of the stone in a re-
markable degree, we purchased ; for it had now become an
article of sale. — It was urged that it had pleased Heaven to
rain down this treasure upon them^ and they would bring

their

238 An Account of a Shower of Meteoric Stones,

their thunderbolts to the best market they could. This was^
it must be confessed, a wiser mode of managing the business
than that which had been adopted by some others at an
earlier period of these discoveries. Strongly inipressed with
the idea that these stones contained gold and silver, they
subjected them to all the tortures of ancient alchemy, and
the goldsmith's crucible, the forge, and the blacksmith's
anvil, were employed in vain to elicit riches which existed
only in the imagination.

Two miles south-east from Mr. Prince's, at the foot of
Tashowa hill, a fifth mass fell. Its fall was distinctly heard
by Mr. Ephraim Porter and his family, who live within 40
rods of the place, and in full view. They saw a smoke rise
from ihc spot, as they did also from the hill, where they
are positive that another stone struck, as they heard it di-
stinctly. At the time of the fall, having never heard of any
such thing, they supposed that lightning had struck the
ground ; but after three or four days, hearing of the stones
which had been found in their vicinity, they were induced
to search, and the result was the discovery of a mass of
stone in the road, at the place where they supposed the
lightning had struck. It penetrated the ground to the depth
ot'two feet in the deepest place ; the hole was about twenty
inches in diameter, and its margin was coloured blue from
the powder of the stone struck off in its fall.

It was broken into fragments of moderate size, and from
the best calculations might have weighed 20 or 25 pounds.

The hole exhibited niarks of much violence, the turf
being very much torn, and thrown about to some distance.

It is probable that the four stones last described were all
projected at the second explosion, and should one be dis-
cpvered on the neighbouring hill*, we must without doubt
rttfer it to the sam€ avulsion,

3. Last of all, we hasten to what appears to havebcea
ihe catastrophe of this wonderful phaenomenon.

A mass of stone far exceeding the united weight of all

♦ Which has since been found, weighing- thirty-six poupds apd a quarter.
1 have seen and wcighe<^ it myself. G. Burr.

which

An Jccount of a Shower of Meteoric Stones. 23l>
which we have hitherto described, fell in a field belonging
to Mr. Elijah Seely, and within 30 rods of his house.

A circumstance attended the fall of this which seems to
have been peculiar. — Mr. Elihu Staples, a man of integrity,
lives on the hill at the bottom of which this body fell, and
witnessed the first appearance, progress, and explosion of
the meteor. After the last explosion, a rending noise like
Ihat of a whirlwind passed along to the east of his house and
immediately over his orchard, which is on the declivity of
the hill. At the SAme instant a streak of light passed over
the orchard in a large curve, and seemed to pierce the ground.
A shock was felt, and a report heard like that of a heavy
body falling to the earth ; but no conception being enter-
tained of the real cause, (for no one in this vicinity, with
whom we conversed, appeared to have ever heard of the fall
of stones from the skies,) it was supposed that lightning
had struck the ground. Three or four hours after the event
Mr. Secley went into his field to look after his cattle. — He
found that some of them had leaped into the adjoining en-
closure, and all exhibited strong indications of terror. Pass-
ing oUj he was struck with surprise at seeing a spot of
ground which he knew to have been recently turfed over,
all torn up, and the earth looking fresh, as if from recent
violence. Coming to the place, he found a great mass of
fragments of a strange-looking stone, and immediately called
for his wife, who was second on the ground.

Here were exhibited the most striking proofs of violent
collision. — A ridge of njicaceous schistus lying nearly even
with the ground, and somewhat inclining like the hill to
the south-east, was shivered to pieces, to a certain extent,
by the impulses of the stone, which thus received a still
more oblique direction, and forced itself into the earth to the
tlepih of three feet, tearing a hole of five feet in length and
four feet and a half in breadth, and throwing large masses of
turf and fragments of stone and earth to the distance of 5Q
and 100 feet. Had there been no meteor, no explosions, and
no witnesses of the light and shc^ck, it would'have been im-
possible for aiiy person contemplating the scene to doubt

that

240 An Atcoiuit of,a Shower of Meteoric St-one's,

that a large and heavy body had really fallen from the skies
with tremendous momentum.

This stone was all in fragments, none of which exceeded
the size of a man's list, and was rapidly dispersed by nume-
rous visitors who carried it away at pleasure. Indeed we
found it Very diflicult to obtain a sufficient supply of speci-
mens of the various stones, an object which was at length
accomplished principally by importunity and purchase.
From the best information which we could obtain of the
tjuantity of fragments of this last stone, compared with its
specific gravity, we concluded that its weight could not have
fallen much short of 200 pounds. All the stones, when
first found, were friable, being easily broken between the
fingers ; this was especially the case where they had been
buried in the moist earth, but by exposure to the air they
gradually hardened. Such were the circumstances attend-*
iog the fall of these singular masses. We have named living
witnesses 3 the list of these may be augmented, but we con-
sider the proof as sufficient to satisfy any rational mind.
Further confirmation will be derived from the mineralogical
description and chemical examination of these stones.

The spejcimens obtained from all the diffi^rent places are
perfectly vsimilar. The most careless observer would in-
stantly p\:onouncc them portions of a common mass, and
different from any of the stones commonly seen on this
globe.

Of their form nothing very certain can be said, because
only comparatively small fragments of the great body of the
meteor have been obtained. Few of the specimens weigh
one pound — most of them less than half a pound, and from
that to the fraction of an ounce. Mr. Bronson*s piece is
the largest with which we are acquainted ; we possess the
next, which weighs six pounds, and is very perfect in its
characteristic marks, and we have a good collection of
smaller specimens, many of which are very instructive.
They possess every irregular variety of form which might be
supposed to arise from accidental fracture with violent forces
On many of them, however^ and chiefly on the large speci--

mens«

An Acctnint of a Shower of Meteoric Stones, 241

fhens, may be distinctly perceived portions of the external
part of the meteor.

It is every where covered with a thin black crust, desti-*
tute of splendour, and bounded by portions of the large irre-
gular curve which seems to have enclosed the meteoric mass.
This curve is far from being uniform. It is sometimes de-
()ressed witli concavities such as might be produced by
pressing a soft and yielding substance. The surface of the
crust feels harsh like the prepared fish skin or shagreen. It
gives sparks with steel. There are certain portions of
the stones covered with the black crust, which appear not
to have formed a part of the outside of the meteor, but to
have received this coating in the interior parts, in conse-
quence of fissures or cracks, produced probably by the in-
tense heat to which the body seems to have been subjected.
The specific ojravity of the stone is 3*6, water being 1. The
colour of the mass of the stone is principally a dark ash, or
more properly a leaden colour. It is interspersed with di-
stinct masses, from the size of a pin's head to the diameter
of one or two inches, which are almost white, resembling
in many instances the crystals of feldtspar in some varieties
of granite, and in that species of porphyry known by the
name of verd antique.

The texture of the stone is granular and coarse, resem-
bling some pieces of grit-stone. It cannot be broken by the
fingers, but gives a rough and irregular fracture with the
hammer.

On inspecting the mass, four distinct kinds of matter
may be perceived by the eye.

1. The stone is thickly interspersed with black globular
masses, most of them spherical, some arc oblong and irre-
gular. The largest are of the t>ize of a pigeon-shot, but
generally they arc much snialler. They can bfe detached
with any pointed iron instrument and leave a concavity in
the stone. They are not attractable by the magnet, and can
fee broken with the hammer.

2. Masses of yellow pyrites may be observed. Some of
them are of a brilliant golden colour, and are readily di-
stinguished with the eye.

Vol. 30. No. 1 1 9. April 1 808. Q s. The

«42 An Account of a Shower of Meteoric Stones^

3. The whole stone is thickly interspersed with metallic
pointSj many of them evident to the eye, and they appear
numerous and distinct with a lens. Their colour is whitish,
and was mistaken by the discoverers of the stone for silver.
They appear to be chiefly malleable iron alloyed with
nickel.

4. The lead-coloured mass which cements these things
together, has been described already, and constitutes by far
the greater part of the stone. After being wet and exposed
to the air, the stone becomes covered with numerous red-
dish spots, which do not appear in a fresh fracture, and arise
manifestly from the rusting of the irv>n.

Finally y the stone has been analysed in the laboratory of
this College according to the excellent instructions of
Howard, Vauquelin, and Fourcroy. The analysis was
hasty, and intended only for the purpose of general informa-
tion. The exact proportions, and the steps of the analysis,
arc reserved for more leisure, and may be given to the phi-
losophical world hereafter. It is sufficient at present to ob-
serve that the stone appears to consist of the following in-
gredients : — sileXy iron, magnesia, nickel, sulphur.

The two first constitute by far the greater part of the
stone — :the third is in considerable proportion, but muclt
ks9 than the others — the fourth is probably still less ; and
the sulphur exists in a small bot indeterminate quantity.

Most of the iron is in a perfectly metallic state ; the
whole stone attracts the magnet, and this instrument takes
up a large proportion of it when pulverized. Portions of me-
tallic iron may be separated, &o large that they can be
readily extended under the hammer^ Some of the iron is
in combinatioii with sulphur in the pyrites, and probably
most of the iron is alloyed by nickel.

It remains to be observed that this account of the appear-
ance of the stone accords very exactly with the descriptions^
now become considerably numerous, of similar bodies which
have fallen in other countries at various periods; and with
specimen?^ which one of us has inspected, .of stones -t^at
have fallen in India, France, and Scotland. The chemical
analysis also proves that ihcir composition is the same ; and

it

An Atcourd of a Shower of Meteoric Stones, 243

It 18 well known to mineralogists and chemists that no such
stones have been found among the productions of this globe.
These considerations^ together with the facts that are im-
mediately to be mentioned, raust> in connection with the
testimony, place the credibility of the facts asserted to have
recently occurred in Weston, beyond all controversy.

The falling of stones from the clouds is an event which
has frequently happened in Europe, in Asia, and in South
America^ The accoutits of such phsenomena were, fcJr a
long time, rejected by philosophers, as the offspring of igno-
rance and superstition. Several facts of this kind, how-
ever, within a few years, have been proved by evidence so
unexceptionable, as to overcome the most obstinate incre-
dulity. It is now admitted not only that such phaenomena
have existed in modern times, but that the accounts of si-
milar events in former ages are in a high degree probable.
As this is the first time that stones are known to have fallen
in this part of America, it may not be uninteresting to those
who have paid little attention to this subject, or who still
hesitate to admit that such things have happened, to see a
statement of several similar events in other countries, and
some of the eviderrce by which they are supported.

In 1492, on the 7th of November, at Eniisheim in Up-
per Alsace, a stone fell from the atmosphere which weighed
260 pounds. Contemporary writers agree in stating, that
on this day, between 1 1 and 12 o*clock in the morning, a
loud explosion was heard at Ensishcim, and that this stone
was soon after seen to fall in a field at no great distance
from the town. This stone, till within a few years, was
preserved in the parish of Ensisheim.

In 1762, two stones fell at Verona, one of which weighecf
200 and the other 300 pounds. Three or four hundred
persons were witnesses of the event.

In 1790, on the 24th of July, a shower of stones fell near
Agenin, Gulenne. About nine or ten o'clock at night a
meteor was seen moving through the atmosphere with very
great velocity. A loud explosion was soon heard, which
•was followed after a short interval by a shower of stone*
over a considerable-extent of country.

' Q 2 la

244 An Account of a Shower of Meteoric Stones^

In April 1802, the same thing happened at L'Aigle,
Biot, a member of the French National Institute, who visited
the place to ascertain the fact, , writes to this effect. Persons
of all professions, manners and opinions,-— ecclesiastics, sol-
diers and labourers, men, women^ and children, — agree in
referring the event to the same day, the same hour, and the
same minute. They say they saw the stones descending
along the roofs of the houses, break the branches of the
trees, and rebound after they fell upon the pavement. They
say they saw the earth smoke around the largest of them,
and that the stones were still hot after they had taken them
in their hands. The mineralogical collections formed on
the spot with the greatest care contained nothing of the
kind. On a sudden, and only since the time of the meteor,
these stones have been found, and within a certain extent.

Within fifteen years past the falling of similar bodies,
under similar circumstances, has happened in Portugal,
Bohemia, France, Great Britain, India, and South America.

To account for the existence of these stones, various
theories have been formed by philosophers. Some have
supposed them to be only common stones struck with light-
ning and partly melted. But this theory has now no advo-
cates. A less fanciful hypothesis is, that they are masses of
matter thrown from volcanoes. But to this there are serious
objections. No such bodies are found near the craters of
volcanoes, or are known to be projected from them. And
in many instances these bodies have fallen several hundred
and even several thousand miles from any known volcano.
Mr. Edward King has varied this theory, and supposes that
these substances are thrown from volcanoes not in stTlid
masses, but in the state of ashes or dust. He supposes that
these ashes descending in a cloud become condensed, take
fire, and produce numerous explosions. According to him,
the pyritical, metallic, and argillaceous particles melt, are
suddenly crystallized and consolidated, and fall in masses
to the ground. This explanation evidently involves as great
difficulties as those which it is intended to obviate. Some
philosophers have supposed that these stones are thrown
from terrestrial comets. Not to mention any oilier objec-
tion

On the Torpidity of Monkeys andotlier Animals, 245

tion to this hypothesis, it will by no means account for
such a phaenomenon as appeared at Sienna in 1 794, when
stones descendt'd, not from a moving meteor, but from alu-
minous cloud. Other philosophers, ascribing to these stones
an origin still more extraordinary, suppose them to be pro-
jected from the moon. Admitting that bodies can be pro-
jected beyond the sphere of the moon's attraction, they must
move round the earth in one of the conic sections, and all
the difficulties attending the preceding hypothesis em-
barrass this. The sul)ject must be acknowledged to be in-
volved in much obscurity, and the phaenomenon, till we
are possessed of more facts and better observations, must be
considered inexplicable.

L. Memoir upon the Torpidity of Monkeys and other Ani^
mals. Translated from t/ie Italian of' M. M^ngali,
Frofessor of Natural History at Pavia^.

Une of the phjenomena most worthy the attention of na-
turalists, is the profound sleep called lethargy, to which a
great number of cold-blooded animals are subject during
winter, and several warm-blooded animals also, such as
monkeys, bats, dormice, hedgehogs, Sec.

Several authors, both aniient and modern, have treated on
this subject ; but as they have not made proper observations
and experiments, their writings leave us in much uncer-
tainty. The National Institute of France has therefore in-
vited the learned of Europe to examine carefully, 1st, the
phaenomena presented in winter by the lethargy of animals ;
Sdly, the cause of this lethargy ; Sdly, why it is peculiar to
these animals.

Without pretending to give a complete solution of a
problem, which, as it is announced, appears to me to be
attended with difficulty, a:ul particularly the latter part of
it, I shall detail what I have remarked respecting several of
the animals in question.

• From Annales (lu Mustum d'Histoke Naturelle, tome ix. p. 106.

g 3 " I flatter

246 On the Torpidity of Monkeys and other Animals,

I flatter myself that the results of my observations will
communicate to the learned the principal phaenomena which
attend the lethargy of these mammifcrous animals, the order
pursued by their principal organic functions, and the nature
of the action of a high or low temperature upon their in-^
ternal oeconomy.

I shall say nothing of the habits of these animals in the
jiatural state, and in the state of slavery ; I shall perhaps
have occasion to speak of this at another time :^— at present
I mean to confine myself to an account of what I have ob-
§erved tn monkeys, which are the most remarkable^ among
the animals subject to periodical lethargy. ^

The principal object of my observations has been to ex-?
amine the various phaenomena presented by monkeys during
their lethargy, far different from the mortal lethargy, which
may take place in all animals from the effects of cold. I
have particularly studied the progress of their principal or^
ganic functions, because physiologists are generally at va-
riance upon this subject; some pretending that these func-»
tions are entirely suspended, and others that they continue,
although in a languishing manner, scarcely sufficient to evince
the existence of the vital principle.

A celebrated naturalist of the last century expresses him^
self in the following manner :-r-

*^ When sleep commences, the respiration then becomes
less ; it ceases when the lethargy is complete. The eyes of
the monkey are then closed, its body is bent in the form of
a bow, it is immoveable and entirely cold. We may roll it
about, throw it up into the air, and use it ill without giving
the smallest signs of life.'' The same author asserts that a
sharper degree of cold, in place of awakening monkeys, ren-
ders their lethargy much more profound.

I shall not quote what other authors have since written
upon the subject, as it is evident they have not made the
observations necessary to enable them to decide upon the
cause.

On the first of December 1803, there were brought to me
at Milan three male moi^keys, taken in the Alps which se-
parate

On the Torpidity of Monkeys and other Animals, 247

parate the territory of Chiavenne from that of the Grlsons^
One oF the three was a little awake: I preserved it two
years, in order to study its habits. The other two were in
the lethargic state.

The same day I weighed the latter, in order to ascertain
how much of their weight they lost in a given time of con-
stant lethargy ; the one weighed 25 Milanese ounces, and
the second 22 ounces 3 deniers *. At first sight they seemed
as if totally deprived of life ; they were rolled up like a ball,
with the nose applied to the anus, their eyes closed, the
teeth locked, and they felt perfectly cold when taken into
the hands.

When pinched, however, or shaken, they gave unequi*
vocal signs of irritability ; and sometimes, although rarely,
I perceived a feeble dilatation and a successive sinking in
the flanks, or other signs of a languishing respiration.

The two monkeys remaiiiled in the most profound lethargy
until January 3d, 1804. Reaumur's thermometer, placed
in the room where they were, having varied from five td
nine degrees above zero, on the evening of this day the
largest awoke and removed from its companion, in order
to find a place where it might be more secure from the cold.

As soon as I saw that it was awake, I weighed both ; and
I found that the largest had lost 18 deniers of its primitive
weight, and the other 17|. At the end of 24 hours, the
monkey which had awoke, again fell into a lethargy, and
remained in this state until the Uth ; t|^e temperature of
the room being from 5 to 8 degrees.

On the 11th in the evening, the external temperature
being about 4 degrees, I exposed the same animal to the
free air on the sole of my window. A short tintfe after-
wards it began to tremble and give signs of pain. I also
remarked a small indication of breathing ; and fearing lest a
greater cold should waken it entirely, I replaced it in its bed
in about an hour. In spite of my precaution its respiration
became more frequent. In fact, two hours afterwards I
J?aun<i it almost entirely awaice j but it had not removed

• Xhe denier is the 24th part of an ounce.

§4 froin

248 On the Torpidity of Monkeys and other Animals.

from its place, and it soon fell asleep again. Other cxperl*
ments awoke it again some days atterwards, and it returned
for the fourth time to its lethargic state in about 24 hours.

I have said that more than once I saw unequivocal signs
of a very slow respiration, I was anxious to ascertain by
experiments and repeated observations if this rtspiration was
regularly periodical. Consequently, on tile 4th ot" Ftbruary,
at nine o'clock in the evening, I placed tlie snjallest monkey
under a b^ll-glass, the edges of .which were in some very
clear lime-water. In the midst of the bell-glass was a pe-
destal, on which was a concave piece of wood wdiere the.
monkey lay as in a nest. 1 took care that the water was
exactly of a level within and without the bell-glass at the
moment of immersion ; and on the 5th of February, at nine
o'clock in the morning, I found that it had risen al)out threq
lines in the inside of the bell-glass, and that a pellicle was
formed at its surface. It now remained to examine the
state of the air contained under the bell-glass, and the na-
ture of the pellicle.

1 tried the air with Volta's celebrated eudiometer, and I
found that it had lost a part of its oxygen ; some drops of
nitric acid, poured upon the pellicle* produced a very brisk
effervescence and liberating carbonic acid. These two ex-
periments convinced me that during the lethargic sleep
respiration is not suspended : whence it may be presumed
that circulation also continues, but with a languor propor-
tioned to that of the respiration. I have since been con-
vinced of this by examining with a good microscope the
wings of bats in the lethargic s(^ate ; and I shall have occa-
sion to speak of thiS'in a subsequent menioir,

The smallest of the two monkeys in my experiment 5
continuing in the most profound lethargy, I fixed my cye§
ppon it, and examining it with attention, I perceived a very
feeble alternate depression and rising in its flanks. I took
jny watch, and I ascertained that these unequivocal signs of
respiration were renewed at intervals of four minutes or four
minutes and a half, and that there were 14 iii an hour j
jind whereas when perfectly awake there were about 1500.
^uch is the law to which these animals are subject in one

Oti tJie Torpidity ofMoiikeys and other Animals* 249

of the principal organic functions in their natural, which I
call their preservative, lethargy, in order to distinguish it
from that produced by an excessive cold ; this part is gene-
rally followed by gangrene and death, and on that account
1 think it should be called mortal lethargy.

If it excite surprise that I placed the monkeys in a tem-
perature of six or nine degrees, T answer, that in general
the mamaii ferae subject to periodical lethargy hide them-
selves in holes where the temperature is mild : without this
precaution they would be awakened by the pain which the
cold would occasion ; and if they were not able to avoid it
they would be seized by the mortal lethargy, when gangrene
and death would succeed.

Indeed, having frequently during the winter visited a
famous grotto in this department, in which were several
hundred torpid bats, I asceitained with a good Reaumur**
thermometer, that the tL-mperature of this grotto was con-
stantly above nine degrees. We may be convinced that
the temperature of the holes they dig is the same, when we
reflect upon their depth, upon the care with which they
close up the entrance, and upon their strewing their beds
with hay. We must also observe, that their fat contributes
much to preserve them from cold. It is true they inhabit
places covered with snow for several months ; but this snovi/-
is useful, as it hinders the frost from penetrating to them.

A moderate temperature is necessary for the continuation
of the preservative lethargy: animals subject to it feel pain,
and are awakened by an increased cold; they tremble, and
show the most ardent desire to find a place where they can
get rid of it; — of this I have been frequently convinced.

At the end of December 1799, some spiders in my apart-
ment were awakened by the sharpness of the cold, and they
turned to all corners where they might avoid it.

On the morning of the 4th of February, 1803, I found
upon the sole of my window a common bat, dead. This
poor animal had been torpid for some months in a hole of
an adjoining wall, and had been, no doubt, awakened
by the intense cold of the preceding night, which was
l\ degrees. It had flown to my chamber window in the

hope

250 On the Torpidlt'if of Monkeys and other Animals.

hope of getting in ; but its wings having been too torpid to
enable it to fly further, on being disappointed, it was at-
tacked with the mortal lethargy, and died.

To return to my observations on the monkeys : —
On the 5th of February, having again weighed them, I
found the smallest weighed 21 ounces, and the second 22
ounces and 21 deniers.

The small one, from the first time I had weighed it un-

o

X\\ the 5th of February, had only awoke once, on the 4th of
January, and continued awake for 24 hours. From this it
results, that since the 1st of January the loss of its weight
was reduced to about 9 deniers, while the largest, which had
jStvoke several times, had lost 33 deniers in the same in-
terval .

This difference of weight proves evidently that the fat of
these animals is very useful : not only do they consume a
part of it during their lethargic state, but they are also fed
by it in the intervals of being awake from a lowered or in-
creased temperature. In fact, we are perfectly certain that
they pass these waking periods without food, and that this
fasting causes no inconvenience.

On the same day, the 3th of February, having placed the
largest of the monkeys on a pedestal, and covered it with a
bell-glass, the edges of which rested on a receiver filled with
lime-water, 1 fixed my eyes upon it for an hour, in order
to have a better view of the phtenomena of respiration ; and
I was convinced beyond a doubt, that during this time the
motions of inspiration and expiration were repeated 15 times
in a distinct manner, and at three intervals of four or five
minutes each.

On the same day, at nine o'clock in the evening, T placed
the small monkey upon the outside of my window in a bed
of hay. It remained for some time immoveable, simply
giving those signs of a languishing respiration which always
continues during lethargy ; but in an hour I perceived that
its respiration became more frequent, and that it appeared
rather asleep than torpid ; so that the external temperature,
which was three degrees and a half above zero, in place of
diminishing the respiration, had considerably increased it.

I would

On tlie Torpidity of Monkeys and other Animals, 251

I would have left it an hour longer iu the same situation ;
but observing that its respiration continued to increase, and
perceiving upon touching it that the heat of its body was
greatly increased, I withdrew it and returned it to its usual
place in the roonn, I flattered myself that it would not
waken entirely ; but having visited it about ten o'clock, I
liot only found it awake, but saw that it had resumed its
natural heat and vivacity : it leapt suddenly from its nest
and hid itself among the hay as if to avoid the cold, or any
other accident which might take it from its gentle lethargy.

Hence it follows, that less time is required to bring mon».
keys out of torpidity than to plunge them into it.

The other monkey, which I had placed under the bell^
glass, assumed in its little cradle a position to preserve
itself from the cold, and continued to give signs of respi-
ration 14 or 15 times in an hour. I also observed that the
water had risen in the bell-glass, and that a pellicle of car-
bonate of lime was formed.

On the 6th of February, the thermometer in the room
being at 6^ or 7°, at one o'clock P. M., the external tem-
perature having risen to 71°, I resolved to expose the
torpid monkey, which had been below the bell-glass, upon
the sole of my window. My object was to ascertain if the
action of cold, when it increased insensibly, would produce
upon the animal the same effects which a sudden transition
caused, although there was never any difference between
the temperature of the room and that of the external atmo-
sphere.

For two hours and a half the monkey exhibited no in-
creased signs of life; but about six o'clock I perceived some
indications of a strong respiration. The night approaching,
the thermometer gradually fell, so that on the outside of
the window the thermometer was at 4° only. At this mo-
ment I saw the monkey agitated by convulsive movements
as if from pain : it afterwards stretched itself in its cradle,
its respiration increased gradually until it appeared no longer
to be torpid, but rather asleep. At seven o'clock it respired
16 times per minute, Whereas while in a torpid state it re-
spired only 15 times an hour. The heat of its body, as

tried

t52 On (he Torpidity of Monkeys and other Animals,

tried by the thermometer, increased with the frequency of
respiration, so that by half-past nine o'clock il was perfect-
ly awake.

Convinced by this experiment that the action of cold,
although it increases almost insensibly, occasions pain to
animals in a state of torpidity, I returned the monkey to its
bed of hay. I tried to make it walk upon the carpet, but it
could not use its hind legs, which were torpid from having
been so far from the chest.

On the 20th of February, at seven o'clock in the morn-
ing, I tried another experiment with the largest torpid mon-
key : I placed it outside my window in a vessel surrounded
by ice and muriate of lime. This mixture produced so in-
tense a cold in the receiver, that the thermometer I placed
iu it fell to 7° below zero.

This sudden transition did not excite any sudden convul-
;jive movements in the monkey : in half an hour I observed
it to give sions of pain. I observed increasing signs of re-
spiration and expiration, which must have fatigued it mucb.
It was eleven o'clock, however, before it was completely
awake. The cold continued very sharp, and it tried to
escape from it several tin>es, by moving from side to side
in great pain throughout the night.

1 visited it several times, and found it always trembling i
jts eyes were half closed. It did not sleep, however, al-
though I left it exposed to the same cold till nine o'clock
next morning. I am convinced that a sharper cold would
in a short time have plunged it into that lethargy which is
followed by death, when no assistance is given to prevent it.

I have here detailed only the general outlines of my ob-
servations upon monkeys. In a subsequent menjoir 1 shall
publish my experiments upon bats, hedgehogs, Sec. : and
I flatter myself that their result will be an accurate know-
Jege of the causes which plunge animals into a torpid sleep.

LI. The

[ 253 ]

LI. The reformed Sexual System of Lhincpus* By Robert
John Thornton, M,D., Lecturer on Botany at Guy*s
Hospital*,

CLASSES.

!• iVioNANDRiA one stamen.

n. DiANDRiA two Stamina.

III. Tkiand.ria three stamina.

IV. Tetrandria four stamina.

V. Pentandria five stamina.

VL Hexandria six stamina.

VI r. Heptandria seven stamina.

VI 11. Octandria eight stamina.

. IX. Enneandria nine stamina.

X. Decandria ten stamina.

XI. DoDECANDRiA 1 2 to 1 9 Stamina.

XII. PoLYANDRiA , „ 20 OF more stamina.

XIII. Cryptogamia concealed stamina.

Orders.

I. Orders taken from the Number of Fist ilia,

I. Monogynia one pistillum,

II. Digynia two pistilla.

' III. Trigynia three pistilla.

IV. Tetragynia ^ . four pistilla.

V. Pcntagynia five pistilla.

VI. Hexugyvia six pistilla.

Vn. Heplagynia seven pistilla.

VIII. Octogynia eight pistilla.

IX. Enneagyjiia nine pistilla.

X. Decagyriia ..>..,. ten pistilla.

XI. Dodecagynia 12 to 1 y pistilla.

XII. Polygynia 20 or more pistilla.

♦ Extracted from Dr. Thornton's Neuj Illustration of the Sexual System of
\Linnieus, just publislied; containing a great number of picturesque botanical
coloured plates of select plants, illusttative of the sexual systen;; the most
ij-icndid botanical work that has yet appeared in any part of the world.

II. Orders

254 The reformed Sexual System of Linnceus,

If. Orders taken from some curious Particularity in the
Stamina,

XIII, Didynamia , . . four stamina, two long, two short*

XIV. Tetradijnamia six stamina, four long, two short.
XV. Icosajidria .... twenty or more stamina, inserted

on the calyx or corolla.
XVI. Monadelphia . . filaments united in one body.
XVII. Diadelplda . . . filaments united, forming two

bodies.
XVIII. r^hjadelphia ,. filaments united, forming three

or more bbdies.
JXIX. Syngenesia , , , five anthers united.
XX. Gynandria . . , stamina arising from the pistil.

XXI. Monoecia stamina apart from the pistil on

the same plant.

XXII. Dloecia stamina apart from the pistil on

different plants.
XXIII. Polygamia .... bisexual flowers, and unisexuaL

Class Cryptogamia has the Natural Orders,
1. Fiiices, II. MuscL III. Algce. IV. Fungi^

REMARKS.

T. — ^The Class IV. Tetrandria, being a numerous one,
Linnaeus chose to separate it into two, and an opportunity
presented itself from the consideration of the difTefences
which occur in plants having four stamina, from the pro-
portion oi ihtst. Didynamia expresses this ifierence; and
the flowers are either ringent ,or personate, a natural tribe.
But as all the ringent flowers are not included in the class
Didynamia, some coming under class II.Diandria, there
can be no good reason for not making this real division of a
class into an order. The system hence becomes more easy
and regidar, and in fact, freq^iently, more natural.

II. — ^The Class VI. Hkxandria, also readily separates
into two parts, from the like consideration of the proportion
in the stamina, and Tetradynamia contains the natural
trihe of cruciform plants.

III.— The

The reformed Sexual System of Li/lnetus, 253

ITT. — ^The Class XIII. Polyandria, also readily divides
into two parts, IVom the consideration of the insertion of
the stamina ; and one of these, the Icosandria of Linnseus,
possesses many edible fndts ; but ad it is not altogether a
natural class, therefore no one can regret seeing this part
distinguished as an order.

IV.— In theMoNADELPHiA of Linnaeus, many of the nu-
merical names, which bad been used to characterize the
classes, are employed to distinguish the orders, or subdi-
visions, as Pentandria, Decandria, &c., and hencje arises
a confusion unavoidably perplexing to the young student,
and which our method, as is evident, completely removes.
The same observation applies to the classes Diadelphia^
Polyadelphia, Gyna?idria, Moncecia, Dioecia, where the
«ame (may I call it so) impropriety occurs. This class in
Linnaeus is not natural, hut, being made into orders, many
ef them then become natural a.s orders, as the Colum-

KIFER^.

V. — The Papilionaceous Flowers, as they are generally
termed, form the order Decandria in the class Diadelphia
of Linnaeus ; but the author, unvv'illing, as it would seem,
to make any breach in so natural an assemblage of plants,
has so far deviated from the principles of his system, as to
refer to that class several genera, which strictly belong to
the preceding class, being in fact Monadelphious, This in-
convenience is entirely obviated in the present scheme,
where Monadelphia 3ind Diadelphia constitute two successive
orders in our class X. Decandria.

Vr. — Polyadelphia is a small, and, as Doctor Smith
observes, " rather an unnatural class,** Most persons are
shocked to sec Citrus, the orange, in this class, and not
in the Icosandria class; for Linnaeus describes it of the
class XVIII. Polyadelphia, order III. Icosandria, Now
in our Reformed Sexual System, it comes under class XIII.
Polyandria, order Icosandria, in juxta-position with other
edible fruits, in the subdivision Polyadelphia.

VII. — Class V. Pentandria, a very numerous class, is
subdivided by Svngenesia, and so formed into two classes
by Linnaeus,, the latter of which, however, as containing

an

i56 The reformed Seocuat System of Linnceus,

an order Monogamia, is not therefore altogether a nahtrat
class. Wc obviate this by making Syngenesia an order^
and the subdivision Polygam'ia to contain the natural tribts
of compound flowers ; whilst, under another subdivisioui
Monogamiay many plants, not having compound flowers^
arrange themselves.

VI II. Against Gynandria, which Doctor Smith calb
** an odd and miscellaneous class," there lies the same ob-
jection, as we observed above, as against the class Dia-
DfiLPHiA, the numerical names of Classes being applied to
Orders, In our scheme, class 11* Diandrta, has an order
Gyiiandria^ which contains the natural tribe of Orchises ;
and thus the mind is delighted to see a natural assemblage
embraced in an order, if not in a class. The separation of
the remainder cannot be regretted, as not possessing amongst
each other the smallest affinity,

IX. Moi\cECiA is a miscellaneous class, and borrows the
names of its secondary divisions from most of the other
classes, as Monandrioy Dia?idr'ia, &c., nay even from
Monaddphia^ Syngenesia, and Gyiiandria ; for all these
become, in Linnseus's Sexual System, orders. In our
scheme, class Triandria, order Monoocia, contains mostly
gTcisses : hence we retain this natural assemblage in the same
class at least, if not in the same order*

X. DicEciA. The same remarks apply here, as in Mo-

KCECIA.

XI. PoLYGAMiA subdivides the classes Moncecla and
Dioecia-, therefore in the logic of science it is in reality an
order.

" Pascitnr in vivis livor, post fata qriiescit.

Turn suis e\ mciitis cukjue tuctur hoiios." Lunn.

Some apolos^y is certainly necessary, after any endeavour
to reform so celebrated and established a system as the
Sexual System of the illustrious Linnreus. Many ; altera-
tions in this system have been attempted. The enlight-
ened pupil of Linnseus, Thunbcrg, abolished the classes
XX. Gynandria y XXI, Mo?iascia, XXI J, Di(ecia, and

XXIir. Po-

The reformed Sexiial Spstem of Linnceits. 237

XX III. Polygamia. Gmelin, professor at Gottingeu, to
the alterations introduced by Thunberg, in publishing a new-
edition of Linnasus's Systenia Naturae, added the abolition
of class XTl. Icosandrin ; and the no less celebrated Doctor
Smith, preserving the rest of the system entire, has abo-
Jished order V. Monogamia, in class IX. Syngenes'ia, and
class XIII. Pvlygamia. *' To his class Polygamia," says
Doctor Smith, " many students of tropical plants jifstly
objected in his lifetime, and he, as well as his son, listened
to their observations." Dr. Withering, in his Arrange-
ment of British Plants, has followed the system of Gmelin.
Professor Martyn, speaking of the changes introduced by
Schreber, in his new edition of Linnasus's Genera Plan-
tarum, says, that his reduction of class XX. Gynandriay
appears " reasonable,'^ yet the singularity of the order Di-
andria surely dL4nanded a separate place to itself. But when
he comes to mention the' incorporation by Gmelin of the
class Icosnndria into the Pohjundria^ he declares this change
to be ^* abominable.'*

I am aware, thaf venturing to reform in such a degree
the Sexual System, as 1 have done, will bring upon me>
with some, much severe reproach. T am conscious, in-
deed, as well as others, that the credit of the Sexual System
of Linnaeus, as an invention, surpasses all power of praise,
and hence has found enthusiastic admirers ; ''and with timid
hands I have ventured to take to pieces the superstructure
he raised, and build up from the old matci'ials, which I have
carefully and religiously preserved, a new edifice, suited
to modern improvement and convenience ; hoping, how-
ever, that those who may, hereafter, publish the works of
Linnaeus, will cdite the Sexual System as delivered by him-
self, and not bring forward, in the works said to be those
of Linnaius, what he never either thought or wrote. For a
full defence of the Rtformed Sexual System, vide my '* Prac-
tical Botany, being a New Illustration of the Genera of
Plants, with Dissections of each Genus," where this subject
has been particularly considered and discussed.

In a word, as by system is only meant a plan io facilitate
the acquirement of the knowledge of plants, the more easy

Vol. 30. No. 1 1 9. Jpril 1808. • R this

tJ5S The reformed Sexual System of LinncmiSt

this is contrived to accomplish the proposed end, the better
such £i system will be accounted ; and I have endeavoured
so to contrive this, that I hope no longer any very great
obstacles can arise in the way of the student, and that this
will plead my excuse with a discerning and indulgent publi-c
for venturing to step out of the beaten path, to attempt the
rc/brma^/o7z of a system which has conferred immortal ho-
nour upon the inventor, and received the general plaudits
and admiration of the learned throughout Europe. It ap-
peared to me more advisable to reform the whole, than to
make any partial amendments ; either to adopt the system
as fklivered to us by Linnaeus, or to have the present sy-
stem, as erected out of the materials of the old -, a system
which I hope may not moulder, like the o-lher sys^tems*,
into the sand of which they were composed, but resemble
the youthful Phoenix arising from the ashes of its parent ;
or, as a rock in the midst of the ocean, may remain until
** the wreck of matter and the crush of worlds/'

It is certainly a great satistaction for me to lind, that al-
though the learned and venerable Professor Martyn has long
openly disapproved of the changes made in the Sexual Sy-
stem by the several reformers, yet he writes to me —

Hxtract €f a Letter to Dr, Thornton from the Reverend
Mr. Martyn —
'^ T by no means disapprove oi your new attempt to ren-
clerthe Sexual System, by the manner in which you have
done it, an easier 7nediitm of attaining a knowledge of plants;
and have been long convinced in my own mind, that we
stri-ve in vain to unite a natural with an artificial arrange^
ment. Upon yo2ir plan, I see 7/0 impropriety in bringing
the OHCHiDE^ into the second class : nor can 1 even objeci
to your altering, as you have done, the separated classes of
Linnxus, Icosandria and Polyani^ria. Yo[ir method is
ably considered throughout ;. for along with you I hold our
great master's system as sacred, and can never approve of

* Not less than fifty-two systeitis of Botany have been published, several
of tliera of very considerable merit, tut not practically good j hence most of
them are now forgotten.

those

On the Manufactures cairiedon at Bangalore, ^^c, ^55

those greater alterations" (he might have sa\d mutilations)
*'' which some of his pupils have niadc,-i-so diflerently is to
be estimated the conduct of persons engaged in the same;
object."

The rev. Doctor Mihie, the learned author of ^^ A Bo-
tanical Dictionary,** writes to me —

Extract of a Letter to Dr, Thornton from the Reverend.
Dr. Colin Milne-—

*' Your Reformed Scheme of the Linncean System has my
entire approbation. It possesses all the admirable and ele-
gant simplicity of that of Rivinus, which has always been
a great favourite with me, from the steady adherence of the
author to the principles of his method, and is eminently
adapted for practice* Your remarks respecting the Sexua}
System are truly excellent; your New Illustration admi-
rable/'

Doctor Shaw, of the British Museum, a gentleman not
less eminent as a botanist than a naturalist, declares "that
he believes^ had Linnoeus been alive, the Reformed Sexual
System "would be that which he himself would have instantly
adopted."

Similar are the flattering opinions also of several other
distinguished botanists, who have expressed their approval
of the Reformed Sexual System. But with extreme diffi-
dence I submit it to the judgment of the world.

LIf. Account of the Manufactures carried on at Bangalore,
and the Processes employed by the Natives in Dyeing Silk
and Cotton*,

JlSangalore, or Bangalura, was founded by Hydcr, and
during the judicious government of that prince became a
place of importance. Its trade was then great, and its
manufactures numerous. Tippoo began its misfortunes by
prohibiting the trade with the dominions of Arcot and Hy-
derabad, because he detested the powers governing both

* From Buchannan's Journey through the Mijsore^ &c.

R 2 countries.

260 On the Mamtfactures carried on at Bangalore,

countries. He then sent large quantities of gpods, which
he forced the rnerchant? to take at a high rate. These op-
pressions had greatly injured the place ; but it was still po-
pulous, and many individuals were rich, when lord Corn-
wallis arrived before it, with his army in great distress from
want of provisions. This reduced hinfi to the necessity of
giving the assault immediately, and the town was of course
plundered. The rich inhdbitants had previously removed
their most valuable effects into the fort ; but these too fell a
prey to the invaders, vvbei> that citadel also was taken by
storm. After the English left the place, Tippoo encouraged
the inhabitants- to conve back, and by promises allured
them to collect together the wrecks of their fortunes, from
the different places to which these had been conveyed. No
sooner had he effected this, than, under pretence of their
having been frie^idly to the English, he surrounded the place
with troops, and fleeced the inhabitants, till even the wo-
men were obViged to part with their mos^t trifting ornaments.
He then kept them shut up within a hedge, which sur-
rounded the town at the distance ofa coss, till the advance
of the army under general Harris made the guard withdraw*
The inhabitants, not knowing wh&m to tru&t, immediately
dispersed, and for some months the place continued de-
serted. The people, however, are now flocking to it from
all quarters ; and although there are few rich individuajs,
trade and manufactures increase apace ; and the imports and
exports are estimated already to amount to one fourth of
what they were in its most flourishing state. The manu-
facturers and petty traders are still very distrustful and timid;
but the merchants, many of whonr have been at Madras,
and are acquainlfd with British |)()licy, seem- to have the
utmost confidence in the protection- of our government.

The trade of the country not havmg been yet opened a
year since the inhabitants had deserted the place, no proper
estimate can be formed of the quantity of exports and im-
ports ; but it is on the increase every montli, and is now
about one fourth of the quantity that was exported and im-
ported in the most flourishing time of Hyder's governments
The son of the person who had then charge of the custom-
house

and the Processes used in Dyeing Silk and Cotton, 261

J)Ouse states the following particulars of the trade at that
period. In one year there were imported 1500 bullock-load^
of cotton wool; 50 bullock-loads of cotton thread; 230
bullock-loads of raw silk ; 7000 bullock- loads of salt ; fo-
reign goods from Madras 300 bullock -loads. At the same
time were exported of betel-nut 4000 bullock-loads, and of
pepper 400 bullock-loads.

From the quantity of the raw materials some estimate
maybe formed of the extent of the manufactures : 1500
bullock-loads of cotton wool, and 50 of cotton thread, make
; rather more than 5100 hundred weight, worth about 8l6o/.,
and 230 bullock-loads of raw silk make 47,437ilb8., worth
about 27,000/.

The cloths here being entirely for country use, and never
haviiTg been exported to Europe, arc made of different sizes,
to adapt them to the dress of the natives ; and the Hindus
seldom use tailors, but wrap round their bodies tbe cloth,
as it comes from the weaver.

1. The cloth which the women wrap round their haunches,
and then throw over their heads and shoulders like a veil,
is from 14 to 17 cubits long, and from 2 to 2^ cubits wide.
It is called shir ay,

2. If these cloths are for the use of girls, they are called
kirigay ; and are from 9 to 12 cubits long, and from 1^ to •
II- cubit broad.

3. The little jacket which the women at this place wear,
is made up in pieces containing 12 jackets, and called ai"
pissa tan. These are 14-1- cubits long, and two cubits or
two cubits and a nail broad.

4. Men wrap round them a cloth called dotra^ which is
from 10 to 12 cubits long, and from 2^ to 2.l cubits broad.

5. The wrappers of boys, called hitcha khana, are 6 or
7 cubits long, and 1^ or If cubit broad.

6. Cloth for wrapping round the head and shoulders of
men, like shawls, is named shalnama ; and is 6 cubits long,
and 2\ broad. Smaller ones are made for children.

7. Paggooy or turban pieces, are fron) 30 to 60 cubits
long, and f of a cubit broad.

Haying assembled the different kinds of weavers, I took
R 3 from

26iJ On the Mamifactures carried on at Bangalore^

irom tberji the following acpount of their various irjanu*
fact urea :

The pj^tti/cgars, or sjlk- weavers, make cloth of a very
rich strong fabric, The patttrns for the first five kinds of
dresses arc similar to each other, but are very much varied by
the different colours employed, and the different figures
woven in the cloth ; for they rarely consist qf plain work.
Each pattern has an aj)propriate name, and, for the com-
njon sale, is wrought of three different degrees of fiueness.
If any person chooses to commission them, whatever parts
of the pattern he likes may be wrought in gold thr<ead ; but,
as this greatly enhances the value, such cloths are never
wrought except when commissioned The fabric of thp
sixth kind of dress is also strong and rich; but the figures
resemble those on the shawls of Qashemire,

The turbans are made of a thjn fabric of cotton and sijk,

7'he piUtuegars make also, in a variety of figured pat-
terns, the first three kinds of dresses of silk and cotton.

They also make sada putayvshina^ or thin white muslins
with silk borders. These are enher plain, or dotted in the
loom with silk or cotton thread ; and are frequently orna-
mented with gold and silver. This is an elegant manufac-
ture, and is fitted for the first five kinds of dresses.

Plain green muslin with silk borders , for the first three
kinds of dresses is also made by the puttuegars', but not
of so fine a quality as that m^de by the devangas, as will be
afterwards mentioned.

The same may be said of the coloured striped muslin
with silk borders, called dti/ari liuvina, whJph is used alsot
entirely for female dresses, and is wrought of various pat-
terns.

The puiUicgars dye much of their own silk; and they
ga\a* me the fi)llowing account of their processes :

The silk is thus prepared for dyeing, the operation being
performed sometimes on the raw material, and sometimes
on the thread. Take 5 seers (3-rWV^^O of silk, 3 seers
(l-^oVel^O of soulu or impure soda, and 1-i- (o-pWo'^-) of
quick-lime; mix the soda and lime with A or 5 seers, or
j^JDOut 308 cubical inches, of water, and boil them for half

aa

and ihe Processes used for Dyeing Silk and Cotton. 263..

an hour. One half of the boiling ley is poured into a wide-
mouthed pot, and one half of the silk is immediately put
into it suspended mi a stick. If it be not sufficiently wet,
it will not take the colour ; and if it be allowed to remain
any length of time, the silk is destroyed. The rest of the
bilk is now dipt into the remaining 1-ey, then washed in cold
water, and dried in the sun. ^

Tf a white silk be wanted, take three seers (I-jVoV^O of
prepared silk, 3 seers of souhi or impure soda, 1 dudu
weight (6/^'^- drachms avoirdupois) of indigo, and \8 see7's
(about 1233 cubical incl>es) of water ; boil them for about
two hours. Thjen wash the boiled silk in some hot water,
and dry it. In this operation much care is necessary, as by
too much of the soda the silk is apt to be spoiled ; and if
it be boiled too short a time it will not be sufficiently white.
The workmen judge of the time by taking up a few threads
on a stick, and putting on them a drop of eold water:
whenever they appear of a proper colour, the silk must be
immediately washed in clean water.

To give the red dye with lac, take ]l-maund (38^y^lb.) of
lac, cleared from the sticks, 1^ seer (O-jSgy-g-lb.) of lodu
bark, l-i- seer of suja car a, or soda, and two dudus weight*
(J S-f'y^o?^ drachms) «f turmeric. Put them into a narrow-
i^iouthed pot, capable of holding 80 seers (5492 cubical
inches), with 40 seers (2746 cubical inches) of water, and
boil them four hours; then de/:;ant the liquor, which is
impregnated with the dye ; and having to the same ma-
terials added 20 seers (1373 cubical inches) more of water,
boil them again for three hours ; decant this liquor into
the former, and then, for three hours, boil the materials
a third time, with 10 seers (686^ cubical inches) of
water. Decant this^ also into the two former, and pre-
aerve, in a covered pot, the whole liquor for eight days.
At the end of this period the workman judges how much
silk his materials will dye. If the lac has been good, it
will dye 5 seers (3TVcV^b')> ^"^ ^^ ^^ be poor, it will not dye
more than 3-i. seers (2-i-VA^t)). For 3 seers of silk take 20
seers (IS-jJ^^o^lb.) of tamarinds, and for two days infuse them
in 18 seers (1235 cubical inches) of water. Then strain the

R 4 infusioft

364 On the Ma?mfactures carried on at Bangalore,

infusion through a thick cloth, till about 5 seers (343 cu-
bical inches) of clear infusion are procured. Put this into
a large open pot with the silk, and warm the^ii until they
be raiher too hot for the hand. Take out the silk, and pour
into the warm infusion of tamarinds three quaricrs of the
decoction of lac, slraiued through a cloth. Then return the
silk, and boil it for three hours. After this, examine the
silk. If it have received a proper colour, nothing liiore is
added ; but if the colour be not deep enough, the remaining
decoction is strained, and added by degrees > till the colour
is" completed. The pot must then be taken from the fire,
and from time to time this silk must be examined with a
stick. If the colour be blackish, some tamarind infusion
must be added. If too light, it must be again boiled with
some more of the decoction of lac: when cool, the silk
must be washed in cold tank water, and dried in the shade.
This is the finest red dye in use here : in some places cochi-
neal is used ; but it is much more expensive. The lac dye
is not discharged by washing.

The puttuegars dye their silk of a pale orange colour,
with the capilipodi, or dust collected from the fruit of the
roller la tinctoria. For 5 seers of silk (S-ToVo^^*) prepared
tor dyeing, take three seers (l-iVoV'^O ^^ cap'di reduced
to a fine powder, and sifted through a cloth ; 4 dudus
(l^^j_9^oz.) weight of scsamitm oil; 1-^ seer (t2-{Si>--^ oz.)
of powdered soulu, or soda; 1 seer (iOtVo^q-oz.) of suja
cara, another kind of soda, and three dudus weight
(1.^3^3^ oz.) of alum ; — and put them in a pot. Then take
2-^ seers (l-rVoV^b.) of soulu, and boil it in about 3^ seers
(240 cubical inches) of water, till it be dissolved. With
this solution moisten the powders that are in the pot, and
form them into a paste, which is to be divided in three
equal parts. Put one of these portions in the remaining so«r
lution of soulu, and heat it, but not so as to boil. Then
put in the silk, prepared as before, and wet it thoroughly.
Take it out, and add a little water, and a second portion of
the paste. This being dissolved, soak in it the silk as be-
fore. Then put in the remainder of the paste with 18 seers
(1235 cubical inches) of water; and, replacing the silk,

boil

and the Processes used for Dyeing Silk and Cotton, 265

boil it for two hours. Then cool it, and having washed it
in the tank, dry it either in the shade or 'Sun, indiflerently.
This is a pretty colour, fixes well, and is cheaper than that
of the lac.

To dye their silk yellow, the piitivegars use turmeric.
For 3 seers {\^^zji-\h.) of silk, take 4 seers (2-j*bVo^b.) of tur-
meric, powdered and sifted : make it into a paste with water,
adding 4 dudtis weight (f-p'o-Jo-^^-) of sesamumoW. Divide
the paste iiUo three portions, one of whi.-h is to be put into
a pot with 8 seers (549 cubical inches) of warm water. In
this immerse the silk prepared as before, and continue the
operation cxacily in the same manner as with the capUi
paste. It must, however, he dried in the shade, and thie
colour then stands very well; which it would not do, were
it dried in the sun.

The piittticgars give their yellow silk to the niiigaru, who
dye it with indigo. It is then washed by the puttuegarsix^
the infusion of tamarinds, and jiftervvards is of a fine creen
colour ; which, if it be dried in the shade, is tolerably weli
fixed.

The jiiUgaru dye all the other colours ; such as light and
dark blue, sky blue, and purple. The silk is never dyed m,
the piece.

The red and orange- coloured silks are mostly in demand.

Some weavers called cuttery, who pretcn^ to be of the
Kshatriya cast, manufacture exactly the same kinds of good*
as the puttuegars, ^

The whole of the demand for these goods, according to
the account of the manufacturers, is in the counrry formerly
belonging to Tip^:)oo : Seringapatam, Gubi, Nagara, Chat-
rakal, and Chin'-rayapattana, are the principal marts.
When the goods are in much deniand, it is customary for
the merchant to advance one half, or e%'en the wholc^
of the price of the goods which he commissions ; but when
the demand is small, the manufacturers borrow money froiii
the bankers at two per cent, a month, and n)ake goods,
which they sell to the merchants of the place. They never
carry them to the public market. The silk is all imported
in the r^w state by the merchants of this place,

Tli<j

2^0 On the Manufactures carried on at Bangalore^

The master weavers keep froii) two to five servants, who
^re paid by the piece. Workmen that are employed on
cotton cloth with silk borders make daily about 3. fa?mm,
or nearly sd. Those who work in cloth consisting of silk
entirely, make rather less, or from -f§- (6f pence) to f (6 pence)
of 2l fanam, according to the fineness of the work. It is
Dot usual for weavers of any kind in this country, except
those of ihe IVh lUani cast, to employ part of their time in
agriculture ; but many persons of casts that ought to be
weavers are in fact farmers. The cuttenj are more affluent
than the puttuegars, and these again are more wealthy than
any other kind of weavers.

Another kind of manufacture is coloured cotton cloths of
a. thin texture, and with silk borders. It resembles one of
the manufactures of the puttuegars, called dutari huvinay
but is coarser. It is entirely fitted for the different kinds of
iien>ale dress 5 and is made of various lengths, from eight to
sixteen cubits, according to, the age and size of the wearers.
In tliis way three different kixids of weavers are employed ;
the shaijnagarv, the canara devangas, and the teliga de-
vQ}7ga$. These people buy the thread at the public markets.
The red thread comes mostly from Advany, Balahari, and
other places near the Krishna river : the various shades of
blue are dyed by the niligaru.

The weavers themselves dye part of the red thread with
the mudd't root, which is that of two species oi morinda ; the
citrll'olia of Linnaeus, and the tern'ifoUa described in my
manuscripts. The colour is dark, but stands washing hi
cold water. In boiling, it fades. The following is the pro-
cess used : — The thread must be divided into parcels eack
weighing one seer (lO-pVoVoz.)- For each parcel take \. secr-
(2yi..-_.Hg. oz.) of powdered soulu, and dissolve it in 4 seers
(274^)^ cubical inches) of water. Put into the solution
^ seer of sheep's dung, and \ seer (S-J^^yV oz.) of sesamnm
oil, and with the hand mix the whole well. Wet the par-
cel of thread in this mixture tjioroughly, and let it hang up.
in the house all night to dry. Next day expose it on a rock
to the sun ; and during the four or five following days it
must be dipped nine times in a solution of -J- seer ( 1 -^J^-^ 02.)

of

wid the Processes used for Dyei?tg Silk and Cotton. 287

oi souluy in one ^eer (a little more than (58 cubical inches)
of water. Between each immersion it must be dried in the
sun. After this, the thread remains in the house ten days ;
it is then taken to a tank, and well washed by beating it on
a stone, as is the usual practice of this country. When it
has been dried, soak each parcel in a solution of two pago-
das weight (1-rJVo- drachm) of alum in one sccr of water, and
jthen dry it again. Infuse one see?' measure (74-fV cubical
inches) of powdered bark of muddi root, in i seers of cold
^vater, and in this soak one parcel of thread; then throw
into a large pot the whole of the parcels that have been
treated in a similar manner. Next day take them to a tank,
beat them as usual, so as to wash them clean, and then dry
them again in fresh infusions oi' miiddi powder. This mus^
be daily repeated, till the colour is sufficiently strong ;
which, if the bark be from the roots of an old tree, will re-
quire six infusions ; but nine infusions of bark from a young
plant will be requisite.

These weavers dye cotton thread green in ihe following
manner .- They send it to the niligaru, who dye it maviy or
a kind of sky blue. The weavers then wash it, and put it
into two seers (1374- cubical inches) of water, containing
^T seer {5'~^^^x>z.) of powdered turmeric, five myrohalans^
powdered, and the juice of ten limes. Here the thread is
l^ept four hours, and the operation is finished. The colour
is a fine green, but very perishable. It is said that the ??///-
garu have the power of fixing it; but they keep their art a
profound secret.

The devangas dye cotton cloth of a fine red colour re-'
sembling that of the pomegranate flower, and ealled gale-
nari. This is done with the coss2imla, or flowers of the
carihnmus tinctorius. The same gives another red colour,
called simply cossumba. Neither of the colours are vi^ell
^xed. The demand for the cossumba dye being much greater
than the country can supply, much of it is imported. 7'his
is always done in the form of powder, which povi'der is
adulterated with the flowers of the yecada, or asclepias gi-
gantea -, on which, account it is cheaper than the flowers
produced in the neighbourhood. The powder is made by

drying

268 On the Manufactures carried on at Bangalore,

drying the flowers in the sun, and beating them in a mor#
tar, and will not keep longer than one year ; the flowers,
if carefully packed iii sacks. and well pressed^ may be pre-
perved for five years.

The cossumha colour is given in the following manner :
— Take \5 sultany seers (9Vr,lb.) of pure cossvmba powder,
and put it on a cloth strainer. Clean it by pouring on wa-
ter, and rubbing it with the hand, till the water runs through
dear. The coss?imba is then to be spread on a blanket, and
mixed with 13 dudus weight (fyrAh^^') ^f ^m'^ car a, and
an equal weight oi' soulu, both powdered. They are gather-
ed together in the centre oF the blanket, and trodden for an
hour by a workman's feet. They are then put upon a cloth
utrainer, supported as usual by sticks at the corners y and
water is poured on them until it passes through the strainer
without colour. This water is divided into three portions :
that which came first, that which came in the middle of the
operation, and that which can}e last ; the first being of the
strongest quality. Then take Oo good limes, or 100 bad
ones, cut each into two pieces, beat them in a mortar, and
strain their juice, through a cloth, into the pot containing
the dye of the first quality. Then put a little water to the
skins, beat them again, and strain off the water into the
pot containing the second quality of the dye. Then add
jTiore water to the lime-skins, and having beat them, strain
it into the dye of the worst quality. The cloth to be dyed,
having been well washed, is put into this last pot, and boil-
ed for an hour and a half. It is then dried in the sun, and
dipped into the second quality of dye, but not boiled. It is
then dried again, and afterwards kept half an hour in the
dye of the first quality. At the end of this time, should
the colour not be sufficiently strong, the cloth must be
boiled in the dye. It is then dried, and the operation is
finished. The cloth commonly dyed is for turbans ; and a
turban 60 cubits long requires 1 5 seers of cossumha.

The only differerice, in the process for dyeing the gulenari,
is, that to the pot of the first quality, as prepared for dye-
ing cossiimba, is added half a seer (A41 cubical inches) of a
decoction of tundu flowers {cedrella toona Roxb. MSS.)

prepared

and the Processes used for Dyewg &ilh and Cotton, 26^

prepared as follows : — Take 24 dadiis weight {9^J'^<^'z.) of
dried Hindu flowers, beat them in a mortar, and boil them
for half an hour in 2 seers (137-i- cubical inches) of water.
Then strain the decoction through a cloth for use.

The devnngas frequently make a very dark blue, which
they call black, by means of the bark of the swamy, or
Sweilenia febrifuga Koxb. MSS. This colour is ciieap j
but its intensity leaves it on the first washing ; whereas the
very deep blue imparted by repeated immersions in indigo,
and approaching near to black, is very high-priced, and
durable. Ir is ihe colour most esteemed by the natives,
who call it black. The devangas take cotton thread or
cloth that has been dyed blue by the nUigarii witi) indigo,
and sprinkle it with a decoction of swamy bark. This is
made by powderlna^ the dry bark, and boihng it for an hour
and a half. While the cloih or thread is sprinkled, it must
be moved with the hand, so as to imbibe the colour equally
in every part.

Tliese weavers say, that they obtain advances from the
merchants, and borrow money from the bankers, exactly
on the same terms as the puitnegaru. They Sell their goods
lo merchants, or to private customers, and never carry
them to the public markets. None of them follow any
other business than that of weaving, and many are in good
circumstances. The shaynagaru are the richest. The ser-
vants are paid by the piece, and make about 20 faimms
(13i. b\d,) a month.

A kind of weavers called hily mugga by the Mussulmans,
but in Tact consistingof the casts called Shaynagam, Padma^
sh(day, and Samay-shalay, weave many kinds of white
muslins,

I. Dutary, striped and chequered muslins, cal^ed in Ben-
gal durias. They are from 28 to 32 cubits long, and from
2 to 1^ broad; and, if commissioned, flowers of cotton, or
gold thread, are frequently woven in them.

ir. Soda sJdllay or plain muslin, like the mvfmiils of
Bengal. These are from 26 to 32 cubits in length, and 1-^
to 2 cubits in breadth,

III. jisto cwmhi, a cloth like the cossaks of Bengal^They

' have

HJO On the Mantifacture^ carried on at Bangalore,

have sometimes striped or silver borders^ and are always
oriiamcuteci with silver at the euds. They are used by men
to wrap round their shoulders.

IV. Turbans IVom 30 to 100 cubits in length, and from
-J^ to 1 cubit in widths and ornamented with silver and gold
thread at the cnds^

Each kind ot cloth has several patterns, and each pattern
is of three degrees of fineness^ which, in the technical lan-
guage of European merchants in India, are marked by the
letters A. B. and C*

These people say, that they receive advances from the
uicrchants, and borrow money from the bankers, in the
same manner as the pnttuegars Aoi Where the cloth is
made on the weaver's own account^ it is sold partly to mer-
chants and partly in the weekly markets. When a weaver
receives advances, he cannot sell any cloth till his contract
be fullilled. Among the Padma shalay there are few ser-
vants employed; but all the males of a family live together,
and work in the same house, very seldom engaging them-
belves to work out for hire. The Samay shalay keep more
servants. The people of these two classes live better than
those employed in agriculture* A man at fine work can
gain difanain (rather more than 8<i.) a day. At coarse work
a man cannot make above Zd* a day. The servants live in
their own houses ; but, although paid by the piece, they
are generally in debt to tl>eir masters, and are consequently
bound in the same manner as the servants of the fiirmers*
This circumstance is applicable to journeymen weavers of
every kind.

The togotaru are a class of weavers that make a coarse,
thick, white cotton cloth with red borders, which among
the poorer class of inhabitants is used as the common waist-
jqloths of all ages and sexes. This kind of cloth goes by the
name of the maaufacturcrs who weave it, and is also of
three degrees of fineness.

The same people tnake rornah, or handkerchiefs with red
borders, from three to five cubits square, that arc commonly
used by the poor as a head-dress. The pieces are about
twenty cubili long, and are divided into a greater or smaller

number

and the Processes used for Dyeing Silk and Cotidn. ^\

number of handkerchiefs, according to their width. They
are also of three degrees of fineness.

The weavers of this class are poor, and say that they can-
not aflford to make the cloth on their own account. They
in general receive the thread from the women in the
neighbourhood, and work it up into cloth for hire. For
weaving a piece that is worth Sfujiams, or 5s. 4iJ., they
get e^fanamSy or is. 8d. This occupies a workman four or
five days ; «o that his daily gains are from four to five pence.
They never cultivate the ground.

The luhalliaru make a coarse, white, strong cloth called
parcaUa. It serves the poorer male inhabitants, throughout
the country, as a covering for the upper parts of their bodies.
The pieces are from 24 to 28 cubits long, and from 1-^ to
1^ broad, and as usual of three different degrees of fineness.
Weavers of this kind live scattered in the villages, and fre-
quently hire themselves out as day-labourers to farmers, or
other persons who will give them employment.

At the weekly markets the cotton wool is bought up, in
small quantities, by the poor women of all casts, except the
Brahmans ; for these never spin, nor do their husbands ever
plough the soil. The women of all other casts spin, and at
the weekly markets sell to the weavers the thread that is not
wanted for family use. The thread that is brought from
Balahari, and other places toward the Krishna, is much
coarser than that which the women here spin.

Such is the account given me by the various weavers ;
but the cloth agents, who are ail of a cast called Nagarity
say, that it is not customary to make advances for goods of
an ordinary kind, unless the demand from a distance be very
great. When this is the case, or when goods of an un-
commonly high price are wanted, in order to enable the
manufacturer to purchase the raw materials, one half of the
value is advanced. The credit is for three months, and for
this time there is no interest paid ; but if the goods are not
then delivered, monthly interest is demanded at the rate of
I per cent, until the contract is fulfilled. The commission
here on the purchase of goods is. only two per cent., and the
agent is answerable for all the suras advanced to the weavers,
8 On

iff On the ^fectns of gahibtg Power in Mechanics.

On confronting some of the richer Shaynagaru with the
Kaoaritt they acknowledged that this statement was true.

The places from whetice agent?; are at present employed
to purchase cloths are, Na^ara, Chairakal, Seringapatam,
Chin*-raya-pattana, Sira, Wadhngiri, and Devund-hully.
A small quantity of cotton and silk cloth for women*9
jackets goes to the lower Carnatic. This h the account of
the Nagarit; but I have good reason to think, that a very
kir2:e quantity of goods, especially »f the silk manufacture
called combaivuftics, are sent to ihat country, and are much
in request an)ong the women of the rich Br^hmans. The
Na^arit say, that the merchants, who import cotton, take
away silk clotlis for ihfe dresdof theBrahmans of both sexes,
and also blue and red cotton stuiTs ; but not in a quantity
sufficient to repay the whole cotton. Daring the former
government of the Raja's family, much cloth went from this
neighbourhood to Tanjore, Ncgapatam, and other parts of
the southern Carnatic : but since to that period, this com-
merce has been entirely at a stop.

The Mangalore merchants send hither for every kind of
cloth. The dress of that country requires cloth only eight
cubits long. The pieces intended for that market have
therefore a blank left in their middle. In Hyder's time
tliere was a great exportation of cloth to Calicut : but the
troubles in Malabar have put an entire stop to this branch of
conuiierce.

[To be continued.]

LIII. On the Means of gaining Power in Mechanics,
To Mr, Tilloch,

SIR,
In reply to the observations and opinion of one of your
correspondents in Number cxvii. of your Magazine, relative
to the means of gaining mechanical power, i regret having
to remark, that instead of the instruction, or satisfactory
infornjaiion, to be expected from an academician, he has
only gtven us antiquated and superfluous objections and

conclusions^

On tfw Means of gaining Power in Mechanics, 273

conclxisions which are quite erroneous and ill founded : —
for as to the former, I had pointedly remarked that this
novelty (of gaining power) was inadmissible on the esta*
bii.^^hed principles of mechanics : and respecting the latter,
his arguments, against his own supposition, concerning la-
tent propertied in the mechanical powers, of which I never
had any idea, by no means proved the impossibility of my
discovering what had escaped the superior abilities of other
men ; because things full as unlikely do sometimes happen.
Nor is he more successful in his confident assertion, that the
engine I have constructed will, at a certain period, require
as much external power to restore it to its former state, as
it had apparently gained power beyond the laws of mecha-
nics by its first effort; because this engine is announced as
an exception to the rules on which he forms his opinions :
and the facts are, that it effects what the established max-
ims held out as being impossible, and that it does not re-
quire such great external poiver to restore it as he supposes.
Hence it may properly be called a novelty. It is, however,
what has long been sought, and what great numbers of
well-informed geniuses in this and other countries are even
now assiduously endeavouring to gain, with the established
principles at their fingers' ends.

To give a drawing or particular description of this engine
in any Magazine, or taking out a patent, would be making
it too public, by putting our continental neighbours, who
are now most closely confederated against us, and intent on
doing us all the injury in their power, on the same footing
with ourselves ; and perhaps give them advantages, which,
being the birth-right of my countrymen, shall, as far as
rests. with me, be wholly secured to them.

It will therefore suffice, f(>r the immediate gratification of
your readers particularly interested in this subject, to state in
general terms, that this engine is a singular, though very sim-
ple, combination and disposition of the mechanical powers.

I lake this opportunity to request the favour of an ansvver
from some of your ingenious and obliging correspondents
to the following question :

Is it possible so to dispose a moving power, (suppose a
Vol. 30. No. 119. ^pW/ 1 SOS. S one

274 On the Identity of Sllex and Oxijgen,

onie pound weight,) as that, during its progress through a
given space, its force shall be constantly increasing, and
thereby produce an accelerated motion exceeding that oi
the moving power at least ten to one ?

I am, sir, your very humble servant,

Bracknell, Berks, £. VlDAU

March 22, 1808.

LIV. 0?i the Identity of Silex and Oxygen, By
Mr, Hume, ff Long- Acre, London,

[Conlinuedfrom p. 17I.J

To Mr, Tillock, .

SIR,

JLiixME., in xU general attractions, aud in its capacity to

neutralize acids, possesses a very superior energy to clay,
and, therefore, is a more decided salifiable base : hence, I'
shall give it the preference in any example, in which an
car,th, as belonging to a distinct genus, is to be contrasted
with silex, whose habitudes and character are so totally dis-
similar.

Nothing is so frequent in nature as an association of two
or more contending elements to form one homogeneous
compound, or to effect some material purpose : thus, an acid
with an alkali, sulphur with a metal, and metals with earths,
niay be adduced as instances, in which this coexistence of
opposites is, perhaps, as essential as two contrary poles to
the same magnet, or the negative and positive wires af the
Voltaic pile. This proximity is no where more -obvious and
frequent than in substances composed of silex and lime, in
which the caustic pungency and other inherent distinctions
of the lime are coerced into such a state of neutrality, as to-
evade every mode of detection, unless the purity of the com-
pound be destroyed and the lime eliminated.

Silex is not only found alone with lime, but follows it
throughout, and in nearly all its modifications; and, gene-
rally speaking, this seems the primary cause of the saturated
condition of lime in all the native carbonates, such as in

chalky

On the Idenliiy of Silex and Oxygen. 67A

thalk, marble, lime-stone, and other fossil bodies, of which
carbonate of lime forms an extensive portion, so much so,
as to render this class of minerals extremely importatit in all
, geological discussions.

This singular coincidence has not escaped notice, and
many very respectable men have advanced opinions Upon the
subject. It has, indeed, been supposed, that there is £t
transmutation of one of these elements into the othef, or 1
graduation of lime into silex ; and it is asserted that th6
recent formation of flint had been perceived, near the sur-
face, in a calcareous mountain, in which, also, animal and
vegetable substances were found petrified by the silex ^
and that rhomboidal crystals were likewise present, passing
from the state of carbonate of lime to nearly pure silex.

It is evident, such a theory as this is not tenable, but
must be involved in difficulty, since it assumes a case, of all
others, the most improbable ; for, according to these pre-
mises, wc are compelled to admit, that the diamond, the
oxygen and the lime, that is to say, the real ingredients of
the chalk, all contribute to the formation of sileX, which is,
avowedly, one of the most perfectly indecomposable of ele-
mentary bodies, and, certainly, much more so than lime*
This conversion of lime into silex is, I presume, quite in-
consistent with general facts, and contrary to every object
in nature which contains these two ingredients among its
constituent principles.

In chalk particularly, which is one of the most plentiful
of nature's productions, as well as in all the other carbonates
oF lime, there is, usually, a very copious assortment of srlex,
under one shape or another ; and this is either so intimately
blended as to be hardly perceptible to the sight, and, often,
can only be extracted by analysis ; or it occurs in the form
of sand, gravel, or what, in common terms, are called^z/z/-
stones» It is necessary to observe, that these stones are
chiefly of an obtuse and rounded figure, and never pointed
and angular; they are frequently found alone, and, from
their appearance and other circumstances, seem to have
suffered a. diminution of ihf^ir original bulk, by yielding up

S"^ a portion,

O",

76 0?i the Identity of Silex and Oxygen,

a portion, from their surfaces, to the surrounding Hiedwim
in which they are imbedded.

The degradation of these flint-stonea is, likewise, strongly
marked by a peculiar opacity, not unlike white glass-enamel
or the superior kinds of porcelain ; and this forms a well-
defined stratum, which covers entirely the whole surface of
the stone, penetrating it to a greater or Tcss depth. It cannot
be considered as a very forced explanation, to aay, that this,
may, probably, be the very point of contact, where this de-
clension of sHex is the commencement of a new modifica-
tion ; and that this terminates eventually in the perfection of
a carbonate, or even of the lime itself, of which silex would
their be considered as the independent progenitor.

That the blunted and nodular shape of the generality of
siliceous stones, is a mark of loss in the primitive mass it-
self, may be explained by many examples. Thus, even ia
common experiments, a sharp or crystal -formed piece of
any substance, capable of solution in an acid, soon loses it*
projecting corners, and, as the action of the acid proceeds,,
gradually becomes less indented, and more smooth or globu-
lar. It is rather a gratuitous conclusion, when the convex
.«hape of pebbles, gravel, and all othet siliceous- stones, is
ascribed to attrition : in some instances this argument may
appear just, but in the more hnportant cases it is, I con-
ceive, extremely fallacious.

The true nature of clay, or, as it is now generally called,
alumincj. vvh«n eonsidered as a primitive earth and simple
element, seems very questionable ; for, notwithstanding
various met^hods have been employed to obtain it ma state of
purity, still this doubt remains. Even, in one of the most
celebrated systems of chemistry, after detailing the best
BBode to accomplish the end, the ^author adds, that the
»lumine ^ will then be nearly pure." One of the specific
characters, peculiar to clay, tends very much to confirm
this suspicion ; it is that particular odour, constantly evoI«*
ving from it, ])erceptible on all occasions, such as ploughing
or stirring upland or garden-groimd, and which is familiarly
known by. the term earthy smelL

It

On the Identity of Silex and Oxygen, 277

It is true, there is also 2i flinty smell, or what the French
-call ** odeiir quarlzeuse;'* but this arises only when the flint
is employed in the act of collision with steel, or against some
Iciml of stone containing this scintillating ingredient, the
silex ; and, on such occasions, I have reason to believe,
■some new compound is the result, in which the presence ot
oxyg-en may be traced to this origin and to no other. The'
<ef!*e.ct of €int upon steel is attended vvilh this singular cir-
'Cum&tanf e, that the particles which fly ofl' are obedient to
the loadstone, and consecjuently must be metallic; but,
the raetal is now dc])rived of its lustre and malleability, it is
a compound^ having imbibed a certain established dose of
oxygen, at the expense of the &ilcx, and tl>e nec:essary caloric
from the atmosphere.

If an ore consist chiefly of lime, silex and metal, and, if
4his metal be saturated witii oxygen, t^e lime and^ indeed,
<the whole compound be tastless and quite insoluble in water,
what other inference can be drawn than this — that the silex
alone is the ostensible and primary cause, both of the insi-
fiidity of the lime and the oxidized condition of the metal ?
Cases of this nature occur very frequently : the ore, which
.produces the new metal titanium,is precisely of that spccieg|
for it is composed of nearly ^qual parts of t,he&e tkree in-
gredients, and nothing more besides..

7'he quantity of silex ia some ores., and in Tnineral sub-
stances containing acids and metallic oxides, is often very
great; in others there is scarcely any: but we may occa-
sionally trace it by its cffectfi, and account for its absence
from the condition of ihcn^gredleDts left in the ore. In the
following example, the quantity of silex remaining in the
compound secerns to be inversely as that of the oxygen, as
if nearly the whole had been expended, and converted into
the oxygen^ which is now blended with the metals.

Thus, z specimen of wolfram, analysed by MM. Vau-
<|uelici and Hecht, contained in the hundred, QQ parts of
tungstic acid, 18 of black oxide of iron, 6*25 black oxide
of manganese, and only 1"5 of silex. Here, I would say, the
whole of the oxygen had been generated entirely at the ex-
pense of the original silex, of which a very little or rather
a mere surplus now remams in the ore. This is not only

S3 . the

278 On the Identity of Sllex and Oxygen*

the most obvious source from whence the oxygen could have
been derived, but, were there any objection, it must be also
noticed that the ore itself had been originally enveloped in
silex (gangue quartzeuse), so much so, that what was su-
perfluous and extraneous adhered so closely, that it was
with great difficulty these gentlemen could detach it, so as
to divide it from the mere ore.

The sulphur, lime and metal, which often constitute the
lead-ore, called galena, or sulphuret of lead, are accompanied
by silex ; and the general neutrality of the whole mixture
maybe ascribed to this, the common oxidizing element;
for, if it be not in the ore itself, it is so very contiguous,
that the matrix is, either entirely or in part, composed of
this substance.

Magnesia, another of the most abundant of the earths,
is never found in a pure state, but, like all others, is either
blended with an acid or concealed by means of silex ; and
whether it be alone or accompanied by alumine, lime, or
any other substance, this is invariably the state to which it
is reduced. Thus, in asbestos, the magnesia, alumine and
lime are sufficiently degraded to be deprived of all external
peculiarities, and to shun the usual tests ; for, though nearly
one half of this mineral is composed of these three bodies,
they are more than counterbalanced by the other element.

Potash and soda, which exist in somany situations, and are
found to be more abnndant than had formerly been suspected,
appear to constitute one of the principal ingredients in va-
rious mineral bodies, particularly in the more huge masses of
matter, in the primitive rocks and mountains, and, probably,
in other substances, in which it has hitherto escaped our at-
tention. These are to be considered, not only to be in the
same predicament as the earths, but, being possessed of
higher powers and more considerable energy as salifiable
bases, they furnish more conclusive examples for elucidating
this subject, and more openly evince the oxgyenating efficacy
of silex. In all substances in which these are found, there
is no appearance of an alkali ; they have, till very lately,
withstood all research ; and even their ready solubility in
water, the peculiar taste, which, it will be granted, is of the

nio?t

On tfie Identity of Silex and Oxygen, 279

most horrid causticity, and other qualities, which charac-'
terize these alkalis, are totally suppressed and softened into
perfect inactivity.

Here, the same agency continues its operations ; for, not
merely the earths, the lime, or alumine, and metals, when
they occur, but a considerable portion of alkali, amounting
in some instances to more than one fifth of the whole, arc
all reduced into one mass of tasteless inoffensive stone. The
leucite, which was analysed by M. Klaproth, contains about
0*22 of potash. 0*23 of alumine, and, 54 of silex ; and from
this, I confess, I can draw no other inference than, —
that the two salifiable bases are deprived of their primitive
characters, entirely by the other ingredient.

The pro-ximity of ali the earths to silex, and the constant
association of this with one or more of the former, is a cir-
cumstance too notorious to dwell upon ; and, considering
the public utility of your pages, it were intrusive to multi-
ply these examples, by bringing forward every case that may
be suitable. We might really confide in almost a random
selection; for all scientific books are fraught with proofs,
and analyses, in which silex, oxidized metals, neutral salts,
or saturated substances, or, in short, where some modifica-
tion of oxygen is indelibly impressed.

Even substances that apparently are independent of our
globe are chiefly formed of Siilcx ; and the meteoric stones,
which, m a highly ignited state, have occasionally been
projected from the atmosphere upon various and distant
places in the world, particularly in Yorkshire, and at Be-,
nares in ihe East Indies, even these contain about half their
weight of silex 5 it has aJso been universally remarked, that
these wonderful productions are always made up of the same
elements — of silex, iron, nickel, magnesia, and a small'
quantity of sulpliur; and nearly in the same uniform pro-
portions in all the specimens that have been analysed hv
other chemists since Mr. Howard, who first published the
exact history of the composition.

These stones are, by mai^y very intelligent men, sup-
posed to have been ejected from some volcano in the moon;
ajnd though iio one has positively asserted it, still the idea

S 4 has

2Sa Royal Society. — Linnctan Society,

has been fostered, and is generally treated with respect. In-
deed, I sec nothing very romantic in this opinion ; and, in
all cases, I think, when we are at a loss to explain, we may
takd the libertv to conjectnre. One of the most celebrated
chemists of the age, and whose correct knowledge of this
and every other subject of science is indippuiable, thus ex-
presses hinisclf upon this subject : " The opinion," says
M. V'auquelin, ** that these stones came from the moon,
however extraordinary it n}ay appear, is still, perhaps, the
least unreasonable ; and if it be true that no direct proofs
can be given, it is no less true tliat no well-founded rea-
soning can be opposed to it : the wiser way, therefore, is
to own frankly, that we are totally ignorant of the origin of
these stones, and of the causes which produce them."

[To be continued.]

LV. Proceed'mgs of Learned Societies.

ROYAL SOCIETY.

1 HE meetings of this learned body, on the 14th and 21st
of April, were occupied in reading an account of a shower
of meteoric stones at Weston in North America. This
account we have been enabled to lay before our readers in
the present Number, by the kindness of the honourable
Mr. Greville. It is by far the best authenticated and pre-
cise account of so singular a phaenomenon that has yet been
published in any country.

LINN.EAN SOCIETY.

April 5. The right reverend the bishop of Carlisle, V. P.
in the chair. A communication froni Doctor Smith, the
president, was read, entitled *' Characters of a new Genus
of Mosses called Hookeria, containing eight Species, &c.'*
Some of these species are new, and others have heretofore
ranked in the genus Hypnum ; from which, however, the
learncdFresident pronounces them to be clearly distinguished
by their reticulated capsules, 'i'hese constitute an essential
character for this new genus, all the species of which, how-
ever, accord in other characteristics. Dr. Smith has named
- thi$

IVernei'ian Natural History Sociefif, 281

this genus after Mr.W. Jackson Hookerj of Norwich, F.L.S.,
a young naturalist of great promise, the discoverer of Biix-
lanrnia ap/u/lla, and author of a work on tiie Jungerinanniae,
which is about to appear.

April 19. The chair was filled this evening by the Presi-
dent, who read a communication oi' his own, on A iie\ir
Genus of .Liliaceous Plants, which he has called Brodcea,
in honour of Mr. Brodie j whose numerous and valuable
illustrations of the botany of Scotland give him a juil
claim to tliis distinction. This pa})er contained some ad-
mirable remarks upon the difficulty which some plants, and
especially the Lihacese, present, of distinguishing between
the calyx and corolla, and upon the doctrine of Jussieu on
this subject. Dr. Smith conjectures that both these organs
may be united where one of them seems to be wanted 5 the
external surface performing the functions of the calyx,
and the internal those of the corolla.

Some interesting letters from Peter Collinson to Linnaeus
were also read by the President, which, he stated, were in-
tended for some future publication. One of them related a
remarkable instance of hybrid fruit on an apple-tree, pro-
duced by the proximity of a tree bearing another kind. The
President mentioned a similar fact which had come under
his own observation near Norwich. A peach- and nectarine-
tree grew close together, and bore sometin^es peaches, some-
times nectarines, and sometimes a fruit partly resembling
each.

WERxMERIAN NATURAL HISTORY SOCIETY.

At the last meeting of the Wernerian Natural History
Society, Professor Jan)eson read an account of a method of
constructing and colouring mineralogical maps. We can-
not give a satisfactory account of this paper withoivt draw-
ings; we shall therefore only observe, that maps executed ac-
cording to this plan show distinctly the figure of the clrffs,
terraces, acclivities and summits of single mountains, and
also the characters of mountain-ranges and mountain-
groups : and the colouring affords a true and harmonious
representation of the alternation, extent, and relative position
of the dififerent rocks that appear al the surface. Profcss^or

Jameson

8 6« Werner ian Natural Hislory Society, '

Jameson at the same time read before the society a series of
mineralogicil queries, — of which a copy is subjoined, —
drawn up with the view of directing the attention of mine-
ralogists to the particular objects pointed out by them.

MIKERALOGICAL QUERIES.

England,

1. Docs the granite of Cornwall belong to the oldest or
the newest granite formation ; or do both formations occur
in that county ?

2. Is the shorl rock of Cornwall disposed in an uncon-
formable and overlying position in regard to the older pri-
mitive rocks ? — If this be its position, on what rock or rocks
does it rest, and what are its other geoguostic relations ?

3. Doeg tlie serpentine of Cornwall belong to the first or
second serpentine formation; and what are the imbedded and
venigenons fossils it contains ?

4. What arc the characters of the different metalliferous
venigenous formations in Cornwall ^?— Are any of them iden-
tical with those described by Werner*, Mohsf^ Fricsle-
ben J, Jameson §, and others ?

5. Do the inclined slaty strata in the vicinity of Ply^
mouth belong to the transition class of rocks?

Q. Does the upper part of the mountain of Cader-^dris
in Wales belong to the newest flaerr trap formation ?

7. Are not the mountains in Cumberland ))rincipally
composed of transition rocks partially covered with the
newest flaetr trap formation ?

8. Is not the porphyry of Cumberland a variety of clink-
stone porphyry ?

p. Does the gypsum of Cumberland belong to the first or
second fla?tr gypsum formation?

Scoltwid.
\, Does the syenltic greenstone of Fassnet Burn, in East

• Neue Theorie von der entstehungder gan<rc> von A. G. "Wernex, 179 J.
+ Beschreibunp^ des Giuben Gchaiides Hininiclsfiirst, von F. Mohs. 1804.
\ Mineralogy Bcinerkiingen bei gelcgenhcit einer Rclse durch den Merk-
•wurdigstcJi Thcil dcs Harz-geberges von Fricsleben. 1795.

§ Mineralo^ical Description of Diimfriesihire; — and Ele.nenU of Geognosy.

Lothian,

IVernerian Natural History Society. 283

Lothian, belong to the transition rocks, or the newest flsetr
trap formation ?

2. Docs clay-stone occur in beds or veins in the coal-
fields of the Lothians ?

3. What are the geognostic characters and relations of th»
porphyritic rock oF the Ochil hills?

4. Is Inch Keith, in the Frith of Forth, entirely composed
,of rocks belonging to the independent coal formation?

5. Are the geognostic relations of the porphyry slate or
elink-stone porphyry of East Lothian the same as in other
countries?

6. What are the geognostic relations of the clay-stone,
compact felspar, and striped jasper of the Pentland hills?

7. Are the upper parts of the Lommonds in Fifeshire, of
Tinfo in Lanarkshire, and of the Eilden hills in Roxburgh-
shire, composed of rocks belonging to the newest flaetr trap
formation ?

8. What is the extent and mode of distribution of the
sienite of Galloway ?

9. Does the Craig of Ailsa in the Firth of Clyde, and the
Bass rock in the Frith of Forth, belong to the newest flaetr
trap formation ?

10. Does the pitchstone of Ardnamurchan belong to the
newest tlretr trap formation ?

.11. Is the granular quartz in the islands of Jura and Isla
subordinate to mica slate, or does it constitute a distinct
formation?

12. Are the Cullin mountains in the island of Skvc
composed of rocks belonging to the newest flaetr trap and
second porphyry formations?

. 13. What are the geognostic characters and relations of
the Scure Eigg in the isle of Egg, one of the Hebrides ?

14. Of what rock is the isle of Staffa composed 3 and
what are its geognostic characters and relations?

15. Is the porphyry of the isle of Rasay porphyry slate ?

16. What are the geognostic relations of the tremolite
of Glen-Elg, in Inverness-shire?

J 7. Does the upper part of Ben-Nevis belong to the

second

^84 Intelligence and Miscellaneous Articles,

second pori>hyry formation : — and if this be the case, on what
does the porphyry rest ?

18. Does the por])hyry of the Brauer near Blair in Athol
belong to the second porphyry formation ?

19. Does the granitic rock in the vicinity of Aberdeen
belong to the granite or sienite formations ?

20. Docs the sandstone of the Shetland islands belong to
the independent coal formation, or to any of the formations
described by Werner ?

21. In what species of mineral repository are the ores of
Sandlodge in Shetland contained; and what are the orycto-
gnostic and geognostic characters and relations of these
ores ?

22. Does the clay-stone of Papa Stour, one of the Shet-
lands, belong to the new flaetr trap or coal formations ?

23. Does the serpentine of the islands of Renst and Fet-
lar belong to the first or second serpentine formations?

LVI. Intelligence and Miscellaneous Articles,

THE MAMMOTH.

With the present Nnmber of the Philosophical Maga-
zine we have given a representation of the skeleton of
this stnpendous animal. Having, in our previous volumes,
given many particulars respecting the mannnoth, we shall
not here repeat them, but content ourselves with the fol-
lowing references to the volumes in which they may be
found :

Vol. xiii. p. 206; vol. xiv. p. 162. 228. 332; vol. xvi.
p. 154. 1/0; vol. XX. p. 100; vol. xxix, p. 141,

See also Plate V, vol. xiv.

The committee to whose management the members of the
association for the discovery of the interior parts of Africa
have intrusted the direction of their affairs, has engaged
aiiolher traveller in their service; a person now in this
country, highly accomplished ibr such a purpose, possessed

of

LiteUigence- and Miscellaneous Articles, SSA

of a strong vigorous constitution, great ardour in the pur^
suit oF knowledge, with a temper of mind ready to suhmit
to great privations, and prepared to accommodate himself
to the various trying situations to which the prejudices of
the inhabitants of that part of the world may possibly ex-
pose him'. .Great expectations are formed of his success.

Mr. Parkinson is expected to publish the second volume
of Organic Remains of a former World, in the beginning of
June. It will contain twenty plates, with the representations
of nearly two hundred fossils of the remains of zoophytes,
coloured from nature ; among which are several proving the
existence in the former world of at least twenty species of
the encrinus. It must be gratifying to the admirers of this
branch of natural history, to learn that great numbers of
these fossils are to be found in different parts of this island.

LECTURES.

Mr. Brookes's Summer Course of Lectures on Anatomy,
Physiology, and Surgery, will commence on Saturday, the
1 1th of June, at Seven o'clock in the Morning, at the
Theatre of Anatomy, Blenheim -Street, Great Marlborough-
Strcet.

In these Lectures the Structure of the Fluman Body will
be demonstrated on recent subjects, and further illustrated
by preparations, and the function of the different organs
will be explained.

The surgical operation's are so performed, and everv part
of surgery so elucidated, as may best tend to complete the
operating surgeon.

The art of injecting, and of making anatomical prepara-
tions, will be taught practically.

Gentlemen zealous in the pursuit of zoology, will meet
with uncommon opportunities of prosecuting their researched
in comparative anatomy.

Surgeons in the army and navy aiay be assisted in renew-
ing their anatomical kowledge, and every possible attention
will be paid to their accommodation as well as instruction.

Anatomical conversaziones will be held weekly, when the
different subjects treated of will be discussed fanuliarly, and

the

286 Lectures,

the students* views forwarded. — ^To these none but pitpifs
can be admitted.

Spacious apartments, thoroughly ventilated, and replete
with every convenience, are open from five o'clock in the
morning, for the purposes of dissecting and injecting, where
Mr. Brookes attends to direct the students, and demonstrate
the various parts as they appear on dissection.

An extensive museum, containing preparations illustrative
of every part of the human body and its diseases, appertain*
,. to this Theatre, to which students will have occasional ad-
mittance.— Gentlemen inclined to support this school by
contributing preternatural or morbid parts, subjects in natu-
ral history, &c. (individually of little value to the possessors)
may have the pleasure of seeing them preserved, arranged,
and registered, with the names of the donors.

Tei^ms. — For :i course of lectures, including the dissections,
51, 5s, For a perpetual pupil to the lectures and dissections,
10/. \0s.

The inconveniences usually attending anatomical investi-
gations are counteracted by an antiseptic process, the result
of experiments made by Mr. Brookes on human subjects at
Paris, in the year 1782; the account of which was delivered
to the Roval Society, and read on the 17th of June 17S4.
This method has since been so far improved, that the florid
colour of the muscles is preserved and even heightened.
Pupils may be accommodated in the house.— Gentlemen
established in practice, desirous of renewing their anatomical
knowledge, may be accommodated with an apartment to
dissect in privately.

Dr. Clutterbuck, Physician to the General Dispensary,
Aldersgate-street, will commence his Summer Course of Lec-
tures on the Theory and Practice oF Physic and the Materia
Medica, on Monday the 30th of May, at Eight in the Morn-
ing, precisely, viz., on the Theory and Practice, on Mondays,
Wednesdays, and Fridays : and on the Materia Medica, on
Tucsdavs and Thursdays, at the same hour.

In these lectures will be given an outline of the structure
and functions of the human b(Kly, as an indispensable preli-

• mi nary

List of Patents for New Inventions, 28/

minary to the knowlege of the nature and treatment of its
various disorders.

The lectures on the materia mcdica will contain the me-
dical and pharmaceutical history of the articles in general.
use ; with an explanation of iheir mode of acting, and their
application to the cure of diseases.

The subjects will be illustrated by occasional reference to
the practice of the Dispensary.

For further particulars, application maybe made at the
Dispensary, or at No. 17, St. PauKs Churchyard.

Dr. George Pearson, Senior Physician to St. Gcorge'i
Hospital, will begin his Summer Course of Lectures on the
Theory and Practice of Physic, MateriaMedica, and Chemis-
try, at his house in George-street, Hanover- square, the first
week in June: — viz. the Medical Lecture at Eight, and the
Chemical at Nine. — Particulars may be known in George-
street, or at St. George's Hospital.

Mr. John Taunton, Surgeon to the City and Finsbury
Dispensaries, &c., will commence his Summer Course of
Lectures on Anatomy, Physiology, Pathology, and Surgery,
on Saturday the 28th of May at Eight o'clock in the Evening,
at his house in Grevillc- street, Hatton Garden, where further
particulars may be known.

LIST OF PATENTS POR NEW INVENTIONS.

To William Francis Snowden, of Oxford-street, in the
county of Middlesex, esq. engine-maker, for certain im-
provements in an engine for cutting hay anj straw into
chaff, and for cutting other articles. February 4.

To John Shorter Morris, of Pancras Place, in the parish
of Pancras, in the county of Middlesex, geut., for his
machine for nfiangling. Febi-uary 4.

To Ralph Wedgwood, of Oxford- strebj, in the county of
Middlesex, gent., for his apparatus for producing several ori-
ginal writings or drawings at one and i^he same time, which'
he callsapennexpolygTaph; or pen and sylograpjnc manifold
writer. February 52.

To Samuel Thomson, of Addle-street, London, calen-
dcrcr; for a machine, engine, or frame for the purpose of
widening or stretching to the width, leather, linen, cotton^
and woollen stufls. March 3. .

METEORO-^

S8S

Meteorology^

METEOROLOGICAL TABLE,

Bv Mr. Carev, op the Strand,
For April 1 803.

Xy,\\% of the
iVlonth.

Thermomerer.

P 5

« ^ ! Height of
^ '^j the BaioiTi.
'c '*^ \ Inchtb.

Weather.

March 27

28

29

30

31

April I

2

3

4

5

6

7

8

9

10

U

12

13

14

15

17

18

19

$0
21

23
24
?5
26

35^

34

33

33

36

32

27

33

42

51

52

53

39

3S

46

48

47

40

48

16 39

37

U

40

34

4l

39

40

4i ^

39 i

s« !

35*^

37

42

39

41

42

40

48

46

54

57

58

51

52

55

54

47

57

58

63

51

53

46

33

47

47

4/

49

49

4^

45

35^
32
33
32

31

30

30

40

49

5i2

52

50

46

45

50

49

39

4G

47 j

46 I

35 !

36 I
35 !
32 j
40 I
35 I
S<J j
40
37

37 J

ii" t

3003
•05

•07

29'93
•91
•62

•87
•82
•60
•32
•68
•85

•91
30-25
•25
•23
•10
•26
•18
•02
•08
•12
29*96
•55
•55
•42
•42
'45
•63
•83
'.Srti

15

30
17
30
36
25
34
17
0
0
12
12
16
26
46
41
O
55
60
6^2
45
62
50
20
3^
15
30
25
15
27
26

Cloudy

Fair

Fair

Cloudy

Cloudy

Cloudy

Fair

Cloudy

Raiu

Kalu

Rain

Cloudy

Fair

Fair

Cloudy

Cloudy

Storms

Fair

Fair

Fair

Fair

Fair

Fair

Snow

gioudy

Storiny

Stormy

Storniv

Cloudy

Cloudy

Cloudy

• I

jN. B. The Barometer'* height is taken af one; o'clock.

[ 269 ]

LVII. Reduction of the Observation of the Transit of Mer^
airy over th^ Sun, observed at the Royal Observatory,
Greenwich^ on the 8th of November, 1802. Commu-
nicated by T. FiRMINGER, Esq,

JL HE particulars respecting this observation are detailed in
the annual sheets published by the Royal Society; but as
these sheets contain nothing more than a mere register of
the astronomical observations made in the Royal Observatory
at Greenwich, they are in general so little interesting, as to
be found in the hands of-but few astronomical or mathema-
tical persons. It was therefore thought advisable, previous
to giving a reduction of this transit, to transcribe the obser-
vation, as given in the account of the Greenwich observa-
tions of that year.

Transit of Mercury over the Sun on the 8th of November,

1802.

^^ I fitted the divided achromatic object-glass micrometer
to the 46-inch achromatic telescope, and adapted the tele-
tscope to distinct vision, by trying it upon a large spot near
the western limb of the Sun ; which 1 had no occasion to
alter duriog the whole period of the observation, as I con-
tinued to see Mercury perfectly distinct and well defined to
the end of the transit. After having made this arrangement,
I began measuring the distance of Mercury from the Sun's
nearest limb, by bringing the exterior limb of Mercury to
touch the interior limb of the Sun, and obtained the follow-
ing set of distances.

Vol. 30. No. 1^20. May 1808. T Time

290

Reduction of the Olscrvation of the

Time per

Trniiiil /^/'^'•^

Appui\mi

7 'i m »

J^'enrest Dutauces

Z,i<«65'

3and^

ITQIlill C-r"'^'^

1 1 inc.

Irych. ten.

ver.

Reduced,,.

h. m.

6.

h. ni.

8.

U 44

34

21 0

48

o

1

12

13

35-1

47

18

3

32

2

li

8

13

5 \'3

48

36

4

50

2

11

12

13

54-3

50

11

6

24

2

2

7

14

ۥ7

51

21

7

34

2

2

17

14

17-4

53

51

10

4

2

2|

«

14

28-1

55

1

11

14

2

2f

13

14

33-5

12 0

21

16

33

2

3

19

14

57-3

1

21

17

32

2

3

24

15

>•?

2

36

18

47

2

3^

2

15

3-3

10

21

26

31

2

3i

7

15

7-3

13

1

29

10

2

3

22

14

59-6

14

40

30

49

2

2{

17

14

36-6

34

6

50

12

2

1

2

13

27-5

39

46

55

51

2

0

7

12

52-p

40

33

56

38

2

0

2

12

49*0

42

19

58

23

1

9\

12

12

37*5

44

21

22 0

25

1

9

24

12

27*5

** From 12^ 50"" to 13^ 40"" per clock, or from 21^ 56"^ to
25^ 46"^ apparent time, I measured the horizontal diameter
of Mercury, which, from a- mean of 26 observations upon
the scale, amounted to 1 1-646 of the vernier; and from a
mean of 27 off the scale, it amounted to 15*255 parts of the
vernier; the mean of both amounts to 11*646 parts of the
vernier, or 8^'*1 7 ; aild the correction of the vernier is— 0"-95
of its parts, or — 0^^*73.

"By a mean of 21 measures the Sun's horizontal diameter
was 5 inches 0^- tenths 8*253 vernier, which diminished
by 0'95 the correction of adjustment leaves 5 inches Of
tenths 7*3' vernier = 5*0646 inches, answering to 32' 25 "*4,
the apparent diameter of the Sun ; from which we derive
the value of the scale.

*' At 14^ 51"" 36'*8, or 23^ 57"* 2r*4 apparent time, I
observed with the 46-inch achromatic telescope the thread
of light between Mercury and the Sun's limb to break, or

the

Transit of Mercury over the Sun, 291

the true inlernal contact at the exit of Mercury. Mr.
Richard Best*, who was observing near nie with a five-feet
achromatic telescope, made the same observation exactly
at the same time. The regular circumferences of Mercury
and the Sun appeared in contact about two seconds later,
the small ligament joining the limbs of Mercury and the
Sun being for that space of lime plainly visible.

* ' The external cbntact of Mercury and the Sun wds otDserved
at 14^ 53"* \6^'S or 23'-^ 59"" P*l apparent time by myself,
14 33 13-8 23 58 58'1 by Mr. Best.

T. FlRMINGER."

Method employed in reducing the Measures of the Distances
taken lij the Micrometer^ hetween the nearest Limbs of
the Sun and Mercury. (See Plate VIII.)

LetO (Fig. 3.) be the centre of the Sun, AC the apparent
path of Mercury, A O, BO, C O, any three observed distancesj
C D a perpendicular to AC, B F a perpendicular to A O,
and B E a right line parallel to C O meeting A 0 in E. Then,
because the differences of times between the observations are
given, and the planet's relative motion is nearly uniform, the
proportion of A C to A B, or of C O to B E, or A O to A E, is
given^ being as the time between the first and third obser-

* To this gentleman, who is extremely fond of astronomy, I was greatly
indebted for the assistance he afforded me during the whole time of the transit :
his readiness in reading off the scale of the micrometer enabled me to pro-
cure at least double the number of measures I could otherwise have done;
Throughout the whole of the measures, every possible care was taken in
making the exterior circular limb of Mercury to touch the nearest interior
limb of the Sun ; but in the middle of the observation, and at a time when
these distances were most wanted, I was prevented from, proceeding with so
much accuracy, or acquiring so great a number as I could have wished, in
consequence of a part of the micrometer coming up against one of the sup-
porting pieces of the object end of the telescope -, a Circumstance I was un-
prepared to meet, having never used the micrometer before, or understood
that such a defect existed. I mentioned this to Dr. Maskelyne when he re-
turned, (he being in Wiltshire at the time of the observation,) who said he
had often met with the same circumstance when observing the lucid parts
of the Sim in a solar ecUpse. This defect was soon afttf.- remedied by Mr.
George Doliond, by a very simple plan I suggested to him of making the sup-
port of the object end of the telescope to shift, by conneciing it to a move-
able collar;

T 8 vaiions

292 Reduction of the Observation of the

vations to the time between the llrst and second. Therefor*
A E, B E^ and O E, are given. But O E is to (B 0 + BE)
as (B O - B E) to (O F -^ F E),and B'F^'lfc '(B E -K F E) x
(B E - F E) ; whence A F, iB F, and the angle O A D he-
Softie known, and conse(|ucntly the nearest distance O D oF
lh6 centres,. as also A D the distance Merfciiry' his to move
from the tirst obsefvatioa to the middle of the transit, vvhicli
distunce divided by the horary motion will give the time.
The horary motion may be -either taken from the tables,- or
found from the observations, being = A B x 3600'^, and
divided by the time elapsed between the first and second
observations taken in seconds, and is the method here used
In determining the nearest approach of the centres, and ap-
parent middle of the transit. But they may with equal ease
be determined from the following algebraic formula which
the analysis gives us. t^et A, B, D, be the first, second,
and third distances, and x, y, z, the elapsed times between
the tirsi and second, second and third, and first and third
observations ; then .will the time between the first ohservatio!)
and the middle of the transit be

_ y ^ '^~+~^' X A^ - z" B"- + .^' D

Aud the nearest distance of the centres will be had from
this ibrmula :

J/ A + z B -f xD^ y A - a ii- 4- .t D x y A -|> g 13 - x D x s- B - i, A 4- rl)
4X1/Z X 2/ A^ - 2 B' Vjc D^

Assuming the apparent horary motion of Mercury
= 355'^-37o, the nearest apparent approach of the centres
comes out = 6o'^'l37, at 21'' 14'" 4()'\d apparent time, as
deduced from the following set of observations. Several
others were calculated, which do not agree so well *, thouoh
their mean approximates to nearly the same quantity. Jf
the horary- motion be deduced from the observations, and
not taken from, the tables, the middle of the transit will
come out about six seconds sooner.

* Owing to the defect arising' from the micrometer not being prdpef! v
VI. ;•. nag cable, as Ims been already itnted. '1'. F. ■■• --

Observations,

It. nearest dist.

Appt. time.

//

h. m. s.

60-215

21 14 40-3

60-213

40 4^

60-171

40- 5"

60-437

39'4

59-648

42-8

Transit of Mercury over the Sun. 293

Olservatidns. 1st, 1 Ith &c 12th

- 1st, llt1i & I6th

- 1st, nth & 15th

- 1st, 11th & 14th

- 1st, lOlh & 18th

Mean 60-137 21 14 405

Tf S'^'S be taken for the mean parallax of the Sun, the
horizontal parallax of Mercury from the Sun on the rlay of
the transit is 4^'' 1221 3, and at 21*^ 14^ 40'-5, the parallax in
longitude will' be — 2"-6775, and the parallax in latitude
+ 2".9923 to be applied to the apparent place : therefore the
geocentric nearest distance of their centres was 62''- 7 1 at
21^' U*" 10' apparent time.

From the above data several theorems have been given for
computing the effect of parallax in accelerating or retarding
the time of the beginning or end of a transit. The follow-
ing method, which is here employed, is as simple as any,
and will be found sufficiently accurate.

Let O (Fig. 4.) represent the centre of the Sun, M D the
relative path of Mercury, M its geocentric place at .egress,
and D at the nearest approach to the Sun's cehlfe : joih O D,
O M, and in D O take D 0, equal to the parallax at the egress
perpendicular to the path ; draw ^'jx, meeting the Sun's limb
in |Lc and parallel to D M, and ^ p perpendicular to D M,
and take p m in D M produced equal to the parallax at the
egress in^ the path ; then will ^u, be the apparent place of
Mercury at the egress, and m its place seen from the
P^arth's centre, as is manifest from the construction. Now
the egress is accelerated or retarded by the time Mercury
takes to describe M w, which is = mp +, pM; and as the:

M O D -h a O D,

angle |u. M p is = ~ — — p M = ftp x cot }

(MOD + ju^OD), and M 7?i = M p + y. p x cot i

(MOD + jw, O D) ; but if m C the parallax in longitude
be put = TT, ftC the parallax in latitude = |S, and the angle
M m C or the angle which the relative path makes with the

T 3 ecliptic

294 ReducitoH of the Observation of the

ecliptic =z (p^ m p will be = tt cos <p + ^ sine (p^ and p p

= /3 cos ^ — TT sine ^ : consequently

M ^« = s-C^Mp ^ <p) X ir cos (|u, M p ~ (^) /3

sinep^Mp "^ sine fj, Up ^''^■'^

will give the value of M ?n with the utmost accuracy. Now
as in the transit of Mercury D ^ must he very small, the
angle /x O D may be safely supposed = M O D, and there-
fore ju- M p = M O D ; whence we have this rule for finding
the effect or parallax.

Rule. The least ciistances of the centres divided by the
Sun's semidiameter give the cosine of an angle which call
w, from which subtract the inclination of the relative path
of Mercury to the ecliptic,' and call the difference %. Let
'Tf be the parallax by which the apparent longitude is di-
minished, (3 that by which the apparent latitude is increased,
m the horary motion of Mercury in its path in seconds and

3600'^

= T, then will the number of seconds by which the

m

ecvress is retarded be expressed

^sine CO sine w

In order to express this rule in numbers, we must find
from the tables the relative geocentric horary motions of
Mercury in latitude and longitude, and hence the angle <p.
Now Lalande's tables give us at the egress the relative
horary motion in longitude = 361^^ '455, and in latitude
5 1''* 7355 <p = 8"" 22^ 26"; and the semidiameter of the
Sun corrected for eradiation = 969": consequently m — 86^
17' 22", V = 77° 54f 5C)'' '. and the formula expressing thq
number of seconds by which the egress is retarded 9'93 *
-\- 2*126^ : from which having given the parallaxes in lati-
tude and longitude, the apparent egress for the centre of the
Earth may be easily computed, and hence the difference of
meridians of two places where the transit has been observed
may be found. The parallaxes may be calculated by the
common methods, or by the following formula, which will
be found sufficiently accurate for that purpose. Let A = the
latitude of th^ place of observation, R = the ARoi the mid-

heaveii;^

Transit af Mercury over the Sitn* ^D5

Iieavefi, P == the horizontal parallax of Mercury from the
Surt, L •=i its longitude, a = obi. ecliptic, thtn will the
parallax in longitude = P cos A sine L x cos (U — P)
COS. a cos L sine (R — P) sine a x cos L sine A, and
the parallax in latitude = P cos a sine x — P sine a
COS \ sine R : whence we have in the present case the parallax
in longitude at the egress or tt = — 2"*972 cos R cos A -f
!2'''62032 sine R cos A 4- 1'1375 sine A, and the parallax
in latitude or /3 = 3"* 78 sine A — 1 "'64 sine R cos A ; of
which the first must be subtracted from, and the second
added to, the apparent place of Mercury.

By computing the reductions from the above formulae, and
applying them to the times of the observed transit at the
different places of observation specified in the following
Table, the differences of their longitudes were as they stand
there determined. The Table also contains the quantity of
the reduction, and the eff'ect of parallax in longitude and
latitude.

Apparent

Time at

Observation.

Reduc-
tion.

Observa-
tions
Reduced.

Longitude

from
Greenwich.

Paralla^c

in
Long.

Paral-
lax in
Lat.

Names of the
Observers.

Paris

h. m. s.
0 7 34

- 17-398

h, m. s.
0 7 16-6

h. m. s.
0 9 24-3

s.
0-9781

3-615

Mean of all.

Gotha

0 41 15-8

-14-3

0 41 1-5

0 43 9-2

0-6348

3-771

Baron Von
Zach.

Utrecht

0 18 40-5

-16-8

0 18 23-7

0 20 31-4

0-8933

3735

M. Von Uten-
havenCalkoen

Leyden

0 15 53

-17-1

0 15 35-9

0 17 43-6

0-9238

3-727

M.VonBeack

Greenwich

23 58 11

-18-7

23 57 52-3

M095

3-653 T. Flrmin^er.

M. Von Zach observed the interior contact only, which
Jiiust be reduced by allowing 1™ 30* for the time between
the contacts ; and reduced to apparent time it gives 0*^ 41°'
J5"8 for the time at observation.

The shortest distance of the centres, combined with the
distance at the moment of the egress, gives the middle of
the transit at 21^ 14™ 28^-6, and hence the time of apparent
conjunction at 21^ 16'"2'-1 : but as the aberration of i he Sun
is — 20"*2, and that of Mercury -j- 18"*33, the true con-

T4 junction

596 Geological Journey to Mount Ramazzo

junction look place 6"^ SS^-S sooner, or at 21^ 9"^ 26*'S ap-
parent tin>e^ when the Sun's true place from the mean
equinox by Mayer's tables was 7** 16^ 17' 13"*3, or 7" 16^
17' 8"*5 if we take into account the correction to be made in
the tables which the Greenwich observations make — 5"
nearly. Hence the place of the node is found to be 1* 13^
5S' 56"-3.

LVIir. Geological Journey to Mount Ramazzo in the Jp-
pcnines of Ligurm ; Description of this Mountain; Dis-
covery of' the true VarioUte in its Bed ; of Lime ; of the
Arragonife ; and of Martial, Magnetic, Cupreous, and
Arsenical Pyrites, in the Steatitic Rock ; Manufacture of
the Sulphate of Magnesia, By M, Faujas St. Fond*.

Xn 1780, Messrs. de Saussure and Pictet visited the moun-
tain Madona della Guardia, elevated 422 toises above the
level of the sea, and of which mount Ramazzo forms a
part. 2\fter having given an excellent lithological descrip-
tion of the first mountain, Saussure thus expresses himself f:
*' On ascending and descending the mountain della Guardia,
we had a view to the westward of a mountain, from which
we were separated by a very deep ravine, and from whicU
we were informed that martial vitriol had been extracted ;
but I had no knowledge of the substance in which it was
found. At the distance from which we saw this mountain,
it seemed mixed with slate and ferruginous earths."

It was this mountain, (known by the name of Mount
Ramazzo,) thus neglected by Saussure, which principally
occupied my attention for two reasons : in the first place,
because I had been told that trenches were dug at the sum-
mit of this mountain, and that a manufacture of sulphate
of magnesia had been established there : secondly, because,
the steatitic and serpentine rocks of this mountain being
united to lime in certain points, I was anxious to visit this
curiositv so seldom discovered.

* "From Annates du Mushim d* HJstoire Naturelle, tome viil. p. 313.
t ^'"!i"S^ acy^'auisurt dans tes Jlpes, tome iv. p. 145.

M. Max!-

in the Jppenines of Liberia. 297

. -M. Maximilian Spinola of Genoa, who is skilled in seve-
ral branches of natural history, M. Viviani a botanist, and
my friend M. Marozari of Vicenza, an excellent minera-
logist, were anxious to accompany me. We took our depar-
ture at six o'clock in the morning from Genoa : we went
in a carriage to Cornigliani, where we visited M. Durazzo's
rich collection in natural history : from thence we proceeded
to Sestri, where M. Alberto Anseldo conducts a manufac-
tory of sulphate of magnesia with great spirit. This gentle-
man acted as our guide in the arduous excursion we were
about to rnake : our route lay through narrow by-ways,
profound ravines, and we were obliged to climb from rock
to rock, which were so flinty and slippery, that they re-
quired some experience in alpine travelling to surmount
them. We left our carriages at Sestri, and immediately en-
tered the bed of the river Charavagna on foot. We ascended
this torrent for about an hour. Its bed is broad, and wholly
covered with blocks of serpentine and other round stones;
which shows that it is subject to dreadful torrents ; but
there is scarcely any water in it in dry seasons. The follow-
ing are the remarks I made on ascending to a lime-kiln,
which I shall speak of by and by.

Notice upon the Stones in the Torrent of Charavagna,

1. Various pieces, larger or smaller, of a grayish steatitic
rock, of a drier grain than that of the other steatites, of
which I shall soon take notice. This rock has fissures or
cracks filled with greenish crystallized epidole, similar to
that of the alps at Oisan in the ci-devant Dauphine. I am
surprised how this rock escaped the attentive and vigilant
eye of Saussure. It is probable, since he has not mentioned
it, that the torrent of Charavagna was not then ])assable, or
at least when he visited the mountain della Guardia.

2. Tender serpentine of a blackish green shaded with
light green, and shining as if varnished, soft and even unc-
tuous to the touch, radiating into white streaks, wiih a
striated and undulous fracture, having a talcky appearance,
and strongly obedient to the magnet.

3. Serpentine, soft, aud analogous to that of No. 2, as to

the

f ^^ Geological Journey io Mount RdiHazzo

the constituent parts; but its colour is of a clearef gre^n :
its surface is much rrtore glossy than that of the preceding,
and its fracture mare gcntrr-liy imduF^tfed : but! what parti-
cularly distinguishes this beautiful speciihcri, which is sev^rt
inches long by five broad, is, that it is not only very attraict-
able by the magnet, but endo\<^ed with a Strong polarity
throughout its wholfe length ; and it attracts keenly al! one.
end, v^'hile it even repels with the Other.

4. Serpentine of a deep green^ with some sliadeS of ^
cTeai'er green, soft to the touch, but harder than (he pre-
ceding, having one of its facets striated, and something like
asbestos.

5. Another serpentine somewhat hard, of a greenish
black, with small spots of a greenish white near to each'
other,' anid which seem to have a tendency to the parallelo-
pipedon form, which gives to this variety of serpentine a false
aspect of black and white antique porphyry. But what
renders the latter remarkable, is, that it coritains in its sub-
sta-^ce, as well as upon its external facets, a multitude of very
brilliant small silvery scales of metalloidal appestrance {dial-
iage), the brilliancy of which is the more lively, as it shines
upon a black ground. This serpentine is strongly attracted
by the magnet.

6. Semi-hard serpentine, attractable, of a deep greenish
black, with some laminae of metalloidal appearance like silver,
and small layers more or less thin, but some of them a line
in thickness, of a substance of the nnctubus appearance of
Steatite ; and its colour being olive-green, shining, and of an
equal and rich tint, seems to be owing to chrome.

7. Semi-hard serpentine of a blueish-gtay, with longi-
tudinal compressed streaks, covered with a slight and trans-
parent couch, or rather with a kind of varnish of a deaf
azure blue. We also distovet* rn the fractures bf this beau-
tiful serpentine, some scales of a metalloid diallagc, and of
a silvery hue ; it is attractable by the magnet.

8. Serpentine of a deep greenish-gray, semi-hard, feebly
attractable, with small round globules, sometimes oblong,
of a compact white or greenish substance, harder and more
tiojnogeneous than that of the stone which contains them,

of

in the Appenlnes of Liguria, 299

of a steatitic aspcgt, and presenting, when we look at it
through the microscope, very fine lineaments which unite
aboiU the centre of each globule. Here we have a true va^
riolite, which ought not to be confounded with an amygda-
loid. The specimen I have described, and which was con-
founded with the other stones I have mentioned in the bed
of the Charavagna, is more remarkable from the globules
being distinct, a little projecting and distinct from each other,
a^ in the variolites of Durance, occupying one-third of the
size of the specimen ; they are also much nearer together,
and seem to touch, and they are confounded afterwards 5
forming at the extremity of the piece but a single couch
where the globules have disappeared, Jind where the same
substance of which they are composed no longer affects the
regular form.

This stone fixed my attention, since it gave me reason to
expect a variolite analogous to that of Durance, in a place
where no jierson had met with it, or even suspected it to
exist.

As the globules, however, of the true variolitfe belong to
a substance very like feldspar and fusible like it, and as I
have neither met with compact feldspar, (petro-silex of
the Germans,) nor feldspar under other forms ; I think the
round variolite which I found, was one of thofe stones
transported in great revolutions of the earth, and out of
its proper place.

I made these refjections when advaricing up the bed of
the torrent ; but I suddenly discovered a stony mass of a
white or greenish hue, weighing more than thirty pounds,
which, at fjrst sight, awakened in my mind the idea of feld-
spar : it may be described as follows :

9. Compact stone, with fine paste, translucid upon the
edges, soft to the touch, of a white slightly tinged wjth asr
paragus green, having the appearance of jade, breaking into
scales rather lamellous than conchoidal, scratching glass
strongly, and emitting some sparks when struck with steel ;
but it is not so hard as the jade. In the blow-pjpe it bub»
bles up almost as soon as the fire touches it, and melts very
soon into a yellowish transparent glass. On breaking this
2 stone.

300 GeologJcal Journey to Mmint. Ramazzo

stone, we perceived, some partsf, of a lively apple-grccn, ar-
ranged in small elongated laminae, flat arfd of a silky lustre,
owing to the diallagc.

I consider this stone as a true compact feldspar, mixed
with a little steatitic- serpentine, and with iridescence
{(iiallage): it is this mixture which contributes, perhaps, to
its great fusibility. I found another piece of it weighing
more than twelve pounds.

With the blow- pipe I made a comparative trial of the
greenish-white globules of the variolite No. 8, which I
found in the bed of the torrent, and they bubbled up and
melted with the same facility as the stone I have described.
Now, as the latter was of a large volume, and did not ap-
pear to come from any distance, for its angles were scarcely
abraded, I presumed that it should abound in some parts of
the neighbouring mountains, in the direction of the torrent
which had received these fragments, and that it v/as perhaps
found in a furrow, or mixed into the paste itself of some of
the serpentines, which T thought 1 should find in its proper
place. In fact, it was natural to think that the junction
of the molecules of feldspar in globules, at the time of the
formation of these mountains, might have given rise to va-
riolltes analogous to those known by the name of varioUtcs
(f Durance ; and thence I did not lose hopes of finding this
kind of stone in the same rock which contributed to its
formation.

10. Finallv, the bed of the torrent, in proportion as I ad-
vanced, presented me with various fragments of a compact
calctreous stone, hard and of a fine paste, susceptible of
beinn; polished, with some veins of calcareous spar which
traversed it ; I saw also some of the same spar adhering to a
rein of white quartz.

These calcareous stones found in a considerable number,
beside the serpentine, magnesian, and feldsparry stones I have
mentioned, left me also some hope of being able to observe
the points of contact of the magnesian with the calcareous
rock in a country quite free of wood, and torn up by tor-
rents, presenting great hills and deep ravines. Reflecting
in this manner, I advanced a little further, and in a deep

in the Appunines of Liguria. 'doi

, recess formed by the 'torrent of the river, I perceived upon
an eminence on the right ban4c of the Charavagna, a rustic
habitation, and a large lime -kiln at work.

Of the Calcareous Stone proper for being converted into Lime:
of its Bed beside Serpentines,

The lime-kihi used for calcining the stone, the singular
situation of which 1 shall soon describe, is of so peculiar
and unusual a construction, that it is worthy, of pur atten-
tionl In consequence of the extreme scarcity of Wood, the
saving of fuel has been their principal object : he;ith
and broom only of a large size are used for this pur-
pose ; these give a brisk but not a durable fire, and it be-
comes necessary to endeavour to preserve the heat as much
as possible. For this purpose, they have constructed of
strong and good masonry, a kind of square tower, sur-
niounted with a pyramid-formed capital of solid stone, which
s.erves as a kind of roof, and forces the heat to reverberate
upon the calcareous stone divided into fragments and in-
tended to be calcined. A simple straight aperture towards
the top of the vault serves for letting out the smoke, and
the humidity which exhales from the calcareous stone and
combustible; and it establishes a current of air necessary for
keeping up the fire, which being concentrated in a great
measure by the obstacles opposed to its wasting, acquires a
greater and steadier intensity. If, in some peculiar circum-
stances, they require a greater current of air, it may be
easily obtained by opening a small door placed, in one of
the faces of the pyraniidal wall, which serves as a roof to
the furnace. The lime-stone is introduced by a door made
behind 'the furnace, and it is withdrawn by the same aper-
ture when it" is calcined : the combustibles are placed below
upon a grating..

The quarry of Hme-stone is not far off, and is to be seeri
in the kind of ravine which serves for the bed of the torrent.
As my intention was to follow it in several points, so as to
become well acquainted with its situation, 1 continued to
asfccnd the torrent of Charavagna, by a route which becomes
more rapid as we advance. The soil was every where loaded
7 i ' with

302 Geological Joimiey to Mount Ramazzo

with serpentines of various kinds similar to those I have
mentioned : but there were also found considerable blocks
of amass composed of fragments of the serpentines above de-
scribed, and of the same lime I have mentioned, and similar
in every respect to that of which the lime is made : this
mass is strongly united by a calcareous sparry cement.

A second kind of mass, also arranged in large blocks, is to
be found in the neighbourhood of the first : both have been
detached from the neighbouring mountains, and do not
seem to have been brought from any distance : the one in
question is composed only of larger or smaller fragments of
different kinds of serpentine, which have entered into the
composition of the neighbouring mountains ; but we find
no lime in it as in the first mass, and the cement which has
imited these serpentines has lime in it, being entirely
stealitic. We soon met with these two varieties of masses
again upon the edges of one of the ravines of the torrent,
on the one edge beside some serpentines, and on tlie
other adhering to lime. It seemed at first sight as if
these masses served as intermedia, and were passing from
one genus to another : but in examining them again, and
reflecting that they must have been formed at the ex-
pense of the calcareous and steatitic rock, both of which
must have had at this period the same consistency and the
same hardness as at present, we could only attribute this
formation to an accidental revolution, long subsequent
without doubt to events of another order, which have
given birth to these mountains of serpentines, and to the
calcareous beds adhering to them, and which have furnished
the materials for these two masses. But let us now cast a
glance upon the lime in its bed, and see if it be cotemporary
with the serpentine rock, or if it be subsequent.

At a certain distance from the lime-kiln, and not far
from the hamlet of Serra, placed in an amphitheatre near
the precipice which hangs over the torrent of Chara-
vagna, we may observe in a very distinct manner a part of
the calcareous layers in their points of contact with the mag*
nesian rock. I give the preference to this spot over that
which is noarertbe lime-kiln, because vye see more distinctly

the

ijhfye Appenines cf Llgip'ia. 303

the junqtiou of bpth s,ubstances ; and the doubts we might
raise as to the lime-stone placed against it secondarily, and
afterwards .against the serpentine rock, disappear entirely
uf>on examining the. j:acts T haye mentioned.

In short, when the torrent in its various overflowings,
and when after storms its waters are' precipitated from
precipice to precipice with a violence and impetuosity car-
rying every thing before it, and laying bare the calcareous
and serpentine beds, ^so as tp present \.\q \vhole at full view ;
w,e then remark tVie gPfiy, hard, and .compact lirne-stQue,
which is modified into white calcareous spar, and forms
large strings or lineaments, which are joined and interlaced
with v^ry .small layers ot linea^iients of ateatitic serpentine.
These lineaments sometimes increase, and are developed
Ipngituflinally, and like stripes of a gray or greenish colour
around longitudinal or circular laminae of calcareous spar of
a white colour. In other parts adjacent, the two substances
forip a Iqind of net work. In a word, we think we can per-
ceive in the union and in the play of these two substances,
so different in their nature, the results of the movement of
the fluid which held both in solution at one and the same
time; and we only know the waters of the sea, and their
long. continuance upon these regions, at very remote periods,
as having acted upon masses which, constitute chains of
mountains.

Every thin^, therefore, inclines us to think, that.in this
case the lime-stone has been attached, or rather joined, to
the magnesian rock, not by an after process, but in one
and the sarpe operation, when, great accumulations of dis-
solved calcareous matters being, in the neighbourhood of
substances which have given bnlh to the serpentine rock,
their mplecules floated in the same fluid, which gave rise to
points of meeting, contact, union, and mixtuie, similar
to those we observe here. Nothing proves ipnore completely
that tbis mixture is ma^e f*jmultancously than the ehemicaf
state of these two substances ; for the purest of the lime-stone
contains 6, 7, .ai)d even 8 pi;r cent, of magnesian earth, while
the serpentine rQckibfUi as much lipac-^ioue i;;v ii^^piass.

Saussure.

304 Geological Journey to Mount Ramazzo

SaussLire had reinarked upon the mountain della Guardia,
an alternation of calcareous and serpentine layers ; whicli,
is perfectly analogous to what I have here described. . But
as such an operation could not be performed at a single jet,
we cannot refrain from remarking here also that nature
never takes into her account the operations of time.

Of the true Variolite (Variolites viridis verus) in the same
Rock in tvhich it has been produced.

As our object was to visit the quarrying of the materials
used in the manufacture of sulphate of magnesia upon
th^* highest part of Mount Ramazzo, M. Alberto Ansaldo,
who guided us, informed us that we must leave the bed of
the Charavagna, pass to the hamlet of Serra, and ascend
over shelving precipices into a direction opposite to that
of the torrent. The road, or rather the pass, was strait,
rapid, and slippery 3 we were surrounded on all sides by ser-
pentine rocks more or less green ; some were hard, others
S'jft : the grain of them also varied ; in some places it was
dry, and in others greasy and unctuous : enormous masses,
placed upon still huger masses, spread spontaneously, some
into irregular leaves more or less turned, and others into
striated pieces imitating asbestos : the d'lallage was distinct^
in some fractures, and exhibited a silvery lustre ; in others -
this was not to be seen ; and in this case the heart of the
stone, being of a deep blackish green, presented shades of a
clearer green.

We had ascended at least six hundred feet in height
from the hamlet of Serra; when being at this height, not
far from a small stream of water which runs through the
pass, and might serve as a point for reconnoitring, I per-
ceived a detached piece of serpentine, the surface of which
was covered with small globules of a whitish green, a little
projecting, and harder than the paste of the stone. I saw
with pleasure that it was a vavlolite not rolled nor trans-
ported from its place, but detached spontaneously by the
effect of moisture, or th«r alternation of heat and cold, from
an enormous mass of serpentine which was contiiruous.

^ This

in the Jppenines of Liguria. 305

This fine specimen is five inches \oug by three bl-oad ; one
of its facets presents the whole characters of a fine green
variohte, with small grains projecting a little, and of a green
much clearer than the heart of the stone, while the opposite
part is a true serpentine of a dark green, without globules
or variolitic spots* We could not doubt, after looking at
this specimen, that the substance which was joined in glo^
bules in order to form this variolite, was the result of an as*
semblage of a certain quantity of feldsparry substance, the
elementsof which had been mixed in the serpentine rock at the
time of its formation. This kind of separation may be con-
sidered as the result of a globulous imperfect crystallization,
determined by the attractive force of the feldsparry mok-
cules, which had more affinity fcr each other than for the
jnagnesian earth J and if these variolitic globules are only
superficial as it were, (for the bed m which we remark thera
is little more thajn three Unes thick,) it is because the sub-
stance of the feldspar was not abundant. In short, the
identity of th€ globulous substance is absolutely the same
with that which I found, separated and in voluminous pieces,
in the bed of the Charavagna, and which I have mentioned
in No. IX of the description of stones found in this torrent.
In fact, having attacked with the blowpipe son>e globules
of the variolite in question, they swelled upon the first at-
tack of the d-re, emitted some air bubbles, and formed a
yellowish transparent glass, like the fddsparry stone abov<3
mentioned.

A^ variolite equally well characterized,^ in the ucighbour*
hood of the rock of which it had once formed a part, gave
me good hopes of meeting with some more of them. These
hoj^s were soon realised ; for after we had ascended 300 feet
higher, we found beneath our feet several flat pieces, but
angular, and of hard serpentine of a lighter or darker green
fiUed with vK^iolitie globules, the grains of which were
much thicker, and penetraitcd into the whole mass of the
serpentine. I gathered several fi;;e specimens, some of which
are six or eight inches loi^ by^n inch in thickness, and of
so decided a character that we eaa easily distinguish with

Vol. 30. No. IftO. May 1 808. U the

306 Geological Journey to Mount Ramazzo

the microscope the commencement of the kind of radiated
crystallization which is peculiar to each globule.

The higher we ascended, the more of these specimens
did we find at the foot of the rocks of serpentine. T ob-
served with interest the general tendency these rocks natu-
rally have to divide into sphnters, or into large flat and
scaly fragments ; (this I attributed to a peculiar alteration
of the iron so abundant in this kind of stone;) when I
suddenly perceived upon the right of the pass, a mass of
serpentine in its bed more than eighteen feet high, with a
base of 40 feet broad, and which seemed as it were iso-
lated, either by natural and spontaneous decomposition of
the most tender parts of the rock, or by some other cause.
1 perceived upon this large mass some parts much greener
than others, penetrating deeply into the heart of this enor-
mous block, which was of a very dull blackish green.

I approached very close, and I ascertained that most of
the spots were produced by parts abounding in true variolite
of a grass green colbur, and white spots or grains, shaded
from an extremely clear green. All these parts formed
in variolites seemed extremely hard : I had soon some
proofs of this, when I struck them with a hammer, and it
was with great difficulty f obtained some good specimens.

Several of these pieces had a multitude of globules ana-
logous and similar in every respect to the variolite of Du-
rance : sometimes, however, the variolitic spots only en-
tered to the depth of an inch and a half into the stone, and
the rest seemed to be nothing else than a pure serpentinous
rock ; at other places the vanolite entered deeper into the
mass : in some places the granulous surface was not much
larger than the palm of the hand ; in others it was double
this size; in short, by continuing to observe more vario-
lites in other blocks, I was convinced that this singular
stone is not in a vein in the masses of serpentines, but that
it exists indifferently, sometimes in one place and some-
times in another, without order or regularity. It is the
same with the arrangement of the globules : we see them
huddled together upon some pieces, and as it were arranged

in

i?i the Jppenines of Liguria, 30/

in an equal and distinct manner, while they are thinly
scattered upon others, or sometimes so close together that
they are confounded, and form merely a large whitish
spot.

I shall finish these details by observing, that I possess
among my numerous specimens a remarkable piece, which
will demonstrate to those acquainted with the composition
of rocks, that the variolite of Mount Ramazzo took its rise
in a true serpentinous rock. I shall now describe this rare
and curious specimen in few words.

Its colour is the same with that of the other serpentines
I have mentioned ; but the rock from which 1 detached it
with the hammer was very hard, its texture very close 5 but
striated at the same time in gi scaly manner; and its scales
frequently interposed between the streaks, and intersecting
them transversely, render this rock difficult to break : it is
torn in some measure rather, than broken, and requires
heavy blows with the hammer. In this way I procured this
fine specimen with a fracture a little undulous, but pure and
clean, and which admits of our seeing upon the two large
faces of the stone its texture, as well as upon the rock it-
self. We see perfectly upon a part which forms almost the
half of the piece, and not only upon the faces but through-
out its whole thickness, a multitude of variolitic globules
of almost equal size, of a clear green, issuing every where
from the streaks and scaly parts of the stone, as if they were
sown in it : these globules become smaller afterwards in
proportion as they approach that part of the specimen
which has none of them ; and this last part is then nothing
but pure serpentine mixed with some irregular and thin-
lineaments of a white colour, not belonging to the variolite,
and some of them slightly effervesce with the nitrid acid.

From the above facts we see that the true variolite exists
in Mount Ramazzo, and that it is cotemporary with the
serpentines in which we find it at the height of more than
1500 feet above the level of the sea. It is to be presumed
we shall find it at a greater elevation, and perhaps in still
greater abundance, in other parts of the Ligurian Appe*
oines.

Us 0/

SOS Geological Journey to Mou7it Ramazzo

Of the Mine of Magnesia upon the highest Part of Mount
Ramazzo,

The route becomes more and more difficult as we approach
the rugged summit, where the quarries and establishment
of M. Alberto Ansaldo are situated, nor do we lose sight of
serpentine rocks the whole way : these are more or less
compact, lamellous, streaked, glossy, unctuous, or dry and
friable. We pass several ravines, and mount from precipice
to precipice, until we come to about 1800 feet above the
kvel of the sea, being the summit of Mount Ramazzo,
where we find a small flat piece of ground, upon which
are built some penthouses for preparing the mineral, and ap-
paratus for stamping, roasting, leying, &c. ; — in a word,
for extracting the sulphate of magnesia in a simple and in-
teresting manner.

This operation consists in carefully collecting a very py-
ritous steatite, which is found rather in heaps and large
fragments than in regular seams : they afterwards roast it,
after reducing it to pieces, in order to evaporate a little of the
arsenic which is combined with it. It is in this operation of
Toasting that the sulphur which is combined with the iron is
disposed to quit its base, and attaches itself to- the magnesian
earth of the serpentine, in order to form the sulphate of
magnesia. They pound this roasted pyrites in a rough man-
ner ; it is then arranged in large heaps, which they water
slightly : the combination with the magnesian earth is then;
finished by a slow fermentation which the matter under-
goes : these earths are afterwards leyed, and a very abun-
dant sulphate of magnesia is obtained, which is purified and
refined in another establishment belonging to M.. Alberto*
Ansaldo, at Sestri.

After having examined the first preparation of the ferru-
ginous and arsenical pyrites of Mount Ramazzo, we entered
the galleries of the mine, which are close to the penthouses t
they are large, but the working of them is not regulated :
they follow the pyrites and the pyritous steatite wherever
they meet it, sometimes in a straight line and sometime*
laterally, just as it presents itself. The excavations are made
, - in

in the Appenines of Liguna* 309

in an Irregular manner, and without any precautions for the
safety of the workmen : the pickaxe, however, alone is
used. The explosion by gunpowder would certainly bring
down the roots of the quarries, which are no where supported
by props or bulwarks. The various specimens I collected
here w^re :

1st. A greenish steatite, the surface of which, as well as
its interior texture, is penetrated with a kind of pyritous
varnish of a bronze colour^ but so light and so efflorescent
(if I may use the expression) that it seems as if the heart of
the steatite, which is black, was shown through this kind of
varnish. This pyritous steatite is very heavy ; it blackens
paper, and moves the magnetic needle strongly. It cou-
tiins a small proportion of copper, but scarcely percep-
tible.

2d. The same steatite, still richer in pyrites, with the
flight yellowish or bronze varnish I have mentioned, which
seems to gild the black serpentine rock, is soft to the touch,
blackening -the fingers, and forcibly obedient to the magnet.
,We find in the same rock arsenical magnetic pyrites, very
tieavy, and with a metallic fracture of a grayish white.

3d. This is a rare and superb specimen, being five inches
nine lines long by four inches broad : the base of it is a ser-
pentine of a dee^i black, a little glossy, blackening paper,
without a pyritous appearance; but very heavy, and strongly
attractable by the magnet, remarkable from needles of trans-
parent white arragoniie, one crystal of which is two inches
three lines Ions; and four lines in diameter, of a hexao'onal
figure, but always without a pyramid. Other crystals of a
still greater diameter are to be seen, sometimes in kinds of
cavities in the specimen, sometimes in the mass irself of
the pyritous serpentine, and seem to have been formed si-
multaneously with the pyritous and magnesian elements of
which this rock is composed.

4th. We find a few yards from the quarries, and a little
lower down, some old excavations, but not so deep : here
there is a striated and silky-like pyrites, with beautiful
green efflorescences qf carbonated copper. This steatite is

Us soft

3 IP On Machines in General.

soft to the touch, and has yellow ochrey spots in it, app$»
rently proceeding from grains of altered cupreous and ter*
ruginous pyrites. M. Ansaldo informed me, that this py-
rites was formerly wrought for the sake of its sulphate of
copper, but abandoned on account of its poverty.

LIX. Essay upon Machines in General, By M. Carnot^
Member of the French Institute , &c, &€,

[Continued from p. 221.]

Problem,

XX. 1 HE virtual movetnent being known of any given
system of hard bodies^ (i. e. that ivhich it would assume if
each of the bodies were free^) to find the real movement which
it should have ihefolloujing instant.

Solution. Let us denominate each molecule of the
system, - - - - - m

Its virtual given velocity, - '- - W

Its real velocity sought, - , - V

The velocity it loses, in such a manner that W is
the result of V and of this velocity, - - U

Let us now imagine that we make the system assume

an arbitrary geometrical movement, and let the velocity

which m will then have be - - - u

The angle formed by the directions of W and V, X

The angle formed by the directions of W and U, Y

The angle formed by the directions of V and U, Z

The angle formed by the directions of W and u, x

. The angle formed by the directions of V and «, y

The angle formed by the directions of U and u^ z

This being done, we shall have the equation s m u\J

cosine x = O (F) ; by means of which we shall find in all

cases the state of the system, by attributing successively to

the indeterminates u different relations and arbitrary direct'

lions.

Definitions.
XXI. Let us imagine a system of bodies in movement \r\

any

Oh Machines in Genet aL 311

any given manner : let m be the mass of each of these bodies,
and V its velocity ; let us now suppose that we make the sy-
stem assume any geometrical movement, and let u be the ve-
locity which w will then have, (and what I shall call its geo-
metrical velocity,) and let y be the angle comprehended be-
tween the directions of V and u \ this being done, the quan-
tity 772 7/ V cosine y will be named the momentum of the
quantity of movement mW^ with respect to the geometrical
velocity u ; and the smn of all these quantities, namely
s m uY cosine y, will be called the momentum of the
quantity of movement of the system with respect to the
geometrical movement which we have made it assume :
thus the momentum of the quantity of movement of a system
ef bodies, iv'ith respect to any geometrical movement, is the
sum of the products of the quantities of 7novement of the ho-
dies which compose it, multiplifd each ly the geometrical
velocity of this body, estimated in the ratio of this quantity
^ of movement. In such a manner that by preserving the de-
nominations of the problem, s m uW cosine x is the mo-
raentum of the quantity of movement of the system before the
shock ; s muV cosine y is the momentum of the quantity of
movement of the same system after the shock ; and s m u U
cosine z is the momentum of the quantity of movement lost
in the shock (all these momentabeing referred to ihesamegco-
Jiietrical movement). Thus, from the fundamental equation
(F) we may conclude, that in the shock of hard bodies, whether
these bodies be all moveable, or some of them fixed, or, what
comes to the same thing, whether the shock be immediate, or
made by means of any machine without spring, the momentum
of the quantity of' movejnent lost by the general system is
equal to zero,

W being the result of V and U, it is clear that we
have W cosine x = cosine y •\- \] cosine z, or m u W co-
sine X — m uY cosine y -\' m 2l\] cosine z, or lastly,
s mu\Sl cosine x = smuY cosine y •\- s m u U cosine z :
now we have found s m 7t \] cosine 3; = .0 ; therefore
s m uW cosine x -i- s muV cosine ?/, that is to say, in
respect to any geometrical movement, the momentum of

U 4 the

3-1 2 On Machines in General^

the qucnitUy of movement of the system^ immediately after
the shock, is equal to the momentum of the quantity of move-
merit immediately htfore the shock.

When we decompose the velocity which a body would
assume if it were tree, into two, one of which is the velocity
it actually assumes, and the other the velocity it loses ; and
reciprocally if we decompose the velocity it loses, into two,
one of them being that which it would have taken if it had
been free, the other will be the velocity it gains : whence it
visibly follows, that what we understand by the velocity
gained by a body, and what we understand by its velocity
lost, are two quantities equal and directly opposite :^ this
being done, the momentum of the quantity of movement
lost by 7n, with respect ^o the geometrical velocity «, being,
according to the preceding definition, m u U cosine 2, the
momentum of the quantity of movement gained by the
same body will be — w z/ U cosine z ; for there is no dif-^
ference between these two quantities, except in this, that the
angle comprehended between u and the velocity gained is the
supplement of that comprehended between u and U ; so that
one of these angles being sharp, the other will be obtuse, and
its cosine equal to the cosine of the other, taken negatively.
Hence it follows^ that the momentum of the quantity of
rnovement lost by the general system, with respect to any
geometrical movement, (which is null, as we have seen
above,) is the same thing as the difference between the mo-
mentum of the quantity of movement lost by any part of
the bodies which compose it, and the momentum of the
quantity of movement gained by the other bodies of the
same system : thus this difference is equal to zero, and thus
the one of these two quantities is equal to the other ; that is
to say, the momentum, of the quantity of movement lost in the
shock hy any part of the bodies of the system, with respect
to any geometrical mpvement, is equal to the momentum of
the quantity of movement gained by the other bodies of the
same system.

We may, therefore, from the preceding definition, col-
lect the thre^ propositions contained in the following

Theorem.

On Machines in General, 313

Theorem.
XXII. In the shock of li(D-d todies, whether this shock le
immediate, or whether it he made lij means of amj machine
jvithont spring, it is clear that in respect io> ajiij geometrical
7novement, —

\st. The momentum of the quantity of movement lost ly
lite whole system is equal to zero,

2d, The momentum of the quantity of movement lost ly
any pait-of the bodies of the system, is equal to the momen-
turn of the quantity of movement gained by the other part,

3d. The momentum cf the quantity of real movement of
the general system, immediately after the shock, is equal (a
tlie momentum of the quantity of movement of the same sy-
stem, immediately before the shock.

it is clear, from the preceding definition, that these three
propositions are radically the same, and are nothing else
than the same fundamental equation (F) expressed in dif-
ferent ways.

We may also remark that these propositions bear a great
relation to those we extract from the consideration of the
Tuomenta relatively to different axes ; but the latter are less
general, and are easily inferred from those established
in XVII.

There is, therefore, as we see by the third proposition of
this theorem, in every percussion or communication of
movement, whether immediate, or caused by the intermedium
of a machine, a quantity which is not altered by the shock :
this quantity is not, as Descartes thought, the sum of the
quantities of movement ; nor is it the sum of the active
forces, because the latter is only preserved in the case where
the movement changes by insensible degrees, as we shall
see lower down, and it always diminishes when there is
percussion, as will be proved in the second corollary.
When the system is free, the quantity of movement estimated
in any ratio, is in truth the same before and after the per-
cussion; but this preservation does not take place if there
are obstacles, any more than that of the momenta of quan-
tity of movements referred to different axes : all these quan-
tities

314 On Machines in GeneraL

titles are therefore altered by the shock, or at least are only
preserved in some particular cases. But there is another
t^uantity, which neither the various obstacles opposed to the
movement, nor the machines which transmit it, nor the
intensity of the different percussions can change ; it is the
momentum of the quantity of movement of the general sy-
stem, with respect to each of the geometrical movements
of which it is susceptible ; and this principle contains in it-
self alone all the laws of equilibrium and of movament in
hard bodies: we shall even see in corollary 1\^, that this law
equally extends to other kinds of bodies, whatever be their
nature and degree of elasticity.

If the shock destroyed all the movements, we should have
V = 0 : therefore the equation would be reduced to s m
W u cosine x = 0 ; which shows us that this case hap])ens ;
namely, that all the movements are reciprocally destroyed
by the shock, in the case where, immediately before this
shock, the movientum of the quantity of movement of the
general system is null, relatively to all the geometrical move-
ments of which it is susceptible.

First Corollary.

XX TIT. Among all (he movements of ivhich any system of
hard bodies acting upon each other is susceptible, whether by
an immediate shock, or by any machines without spring, that
movement ivhich shall really take place the instant after-
wards will be the geometrical movement, which is surh that
the sum of the products of each cf the masses, by the square
of the velocity which it ivill lose, is a minimum, i. e. less
ihan the sum of the products of each of these bodies, by the
velocity it would have lost, if the system had taken any other
geometrical movem'^nt.

Here it must be remarked, that, by giving for the mini-
mum the sum of the products of each mass, by the square
of its velocity lost, I understand solely that the diffe-
rential of this sum is null ; i, e. that its diflerence from
what it would be if the system had a geometrical move-
ment infinitely little different froni the first, is equal to zero :

thus

On Machines in General. Z\%

thus Ibis sum mav be sometimes a maximum, or even nei-
ther a maximum nor a mi?iimum ; and 1 have only to establish
d s m U* = 0.

Demonstration. — It is at first evident that the true move-
ment of the system after the shock should be geometrical ;
for geometrical movements being those which do not alter
the action which is exercised among bodies, it is clear that
the first in order is the same movement as assumed by the
system : it is therefore required to know, which, among all
possible geometrical movements, is the one that should take
place. Now, supposing that it should take another infinitely
Jittlc different from that which we are seeking, the velocity
of each molecule m would then have been V; let us decom-
pose V'' into two, one of which shall be V, i. e. the real ve-
locity, and the other V' : this being done, it is evident that if
the bodies had not other velocities than these last V, the
movement would be still geometrical, for V^^ is visibly the
riesult of V' and of a velocity equal and directly opposite to V:
now, bv hypothesis, the molecules taken two by two do not
tend, either in virtue of V, or in virtue of —V, to approach
or recede, since in these two cases the movement is geo-
metrical: thus, by. supposing that the molecules w have at
once the velocities V and — V, or their result V', they
will neither knd to approach nor to recede; and therefore
the movement will then be geometrical : thus, if we
call z' the angle comprehended between the directions of V"
and U, we shall have by means of the fundamental equation
(F) s m U V' cosine 2 = 0: on the other side, let us call
U' the velocity which m would lose if its effective velocity
were V, so that W would be the result of V and U^ it
would necessarily follow that U' would be composed of U
and of a velocity eq.ial and directly opposite to V'; whence
it evidently follows, that V'—U or d U z= — V' cosine
2"; therefore the equation s m U V' cosine z' — 0, found
above, becomes s 7?i \J d U -= 0 or d s jn U' = 0.

Suppose, for cxaniple, tv\o globes A and 13 striking each
other obliouely, I demand their movements after tlie
phock.

Suppose

316 On Machines in General,

Suppose that the velocity of A, estimated according to
the line of the centres, was before the shock g, and after the
shock V ; that the velocity of B, also estimated according
to the line of the centres, was before the shock I, and after
the shock u; that {he velocity of A, estimated perpendicu-
larly to the same line, was before the shock a, and after the
shock V ; finally, that the velocity of B, also estimated per-
pendicularly to this line of the centres, was before the shock
l\ and after the shock u' ; this being done, by our proposi-
tion, the movement being necessarily geometrical, we must at
first have V= 7^; thus the velocity lost by A, according to the
line of the centres, will be a — w, and that lost by B, in the
same direction, will be Z' — 2^ : besides, in the direction per-
pendicular to the line of the centres, the velocity lost by A
will be a' —V', and that lost by B will be h'—u'; there-

fore i/(a — «)* + (a' — V')* will be the absolute velocity

lost by A , and that lost by B will be // (i — u) ^ ^ {h' — u') *:
therefore, according to the proposition, we should have
J [A (a - uY + A ((?' -Vy + B {h^uy + B (^' - w) ^]
= 0,orA(a-z/) d u •{• K (a'-V) dY' + B {h'-u)du-\-E
^I'^u") d u' = Oj an equation which should generally take
place, 2. e. whatever be the values of du, dY\ and d u' :
therefore the co -efficient of each of these differentials must
be equal to zero ; which gives V = g', u' ~ h' ^ and u—Ka
+ Bi. a.E.D. ;^^^

It is clear that this proposition contains all the laws of
the shock of hard bodies, whether this shock be immediate,
or be made by means of any machine, since it assigns the
character nnder which we recognise, among all possible
movements, that which should really take place at each in-
stant : this principle has a considerable analogy with that
found by M. Maupertuis, and by him called prindpe de la
snoindre action. See his "Essai de Cosmologie.'*

Second Corollakf.
XXIV. In the shock of hard bodies, whether some of them
,uref.xcd, or all moveable, or {iv hat comes to the same thing)

whether

On Machines in General, 317

whether the shock be immediate^ or given hj means of any
machine without spring, the sum of the active forces before
the shock is always equal to the sum of the active forces
ajter the shock, plus the sum of the active forces which would
take place if the velocity which remains to each moveable
body were equal to that which it has lost in the shock.

That is to say, we must prove the following equation ,
5mW* = 5 Tw V* -f 5 771 U^ Now it is easily deduced from
the fundamental equation (E) ; for W being the result of V
and U, it is clear that W V and U are proportional to the
three sides of a certain triangle : thus by trigonometry we
have W^ = V* 4- U* + 2 V U cosine z : therefore s wW*
= s mV^ + s mU^ + Q s mVlJ cosine Z : now by the
equation (E) we have s mV \J cosine Z = 0 ; therefore
the preceding equation is reduced to s m VV^ = smV^ +
s m U*. Q. E. D.

We see, therefore, as has been said (XXT), that by thi:^
transformation the analogy of the equation (E) with the pre-
servation of the active forces becomes striking : we may also
easily demonstrate the one by the other, as we shall see in
XXVI.

The analogy of this same equation with the preservation
of the active forces in a system of hard bodies the move-
ment of which changes by insensible degrees, is still more
evident, since it then regards a case peculiar from that we
have examined ; it is in fact visibly the particular case where
U is infinitely small, and therefore U^ is infinitely small of
the second order ; this reduces the equation to s m W* =^ s 7n
V* : but this preservation will be explained more at length
in the following corollary.

Third Corollary.

XXV. When any system of hard bodies changes its move-
ment by insensible degrees ; i/', for a moment^ we call m the
Tuass of each of the bodies, V its velocity, p its vis motrix,
R the angle comprehended between the directions ofV and p,
u the velocity which m would have if we made the system take
any geometrical movement, r the angle formed by u and p,
3 ythe

S 1 8 On Machines in General,

y the cm gle formed by V and u, d t the element of the time ; tee
shall have these two equations:

smVpd /cosineR — s wVfl^ V=0:
smup d t cosine r— s mud (V cos y.) = 0.
Demonstration. — In the first place, pdt cos R is visibly
the velocity which the vis motrix p would have impressed
ujx)n w in the direction of V, if this body had been free .-
besides, dY \s the velocity which it would in reality receive
in the same direction ; therefore pdt cosine R — (i V is
the velocity lost by 7n in the direction of V, in virtue of the
reciprocal action of the bodies : it is therefore this quantity
that we must put for U cos. Z in the fundamental equation
(E), which becomes by this substitution s mV p d t cosine.
R ~ 3' m V dV = o', being the first of the two equations
which we had to demonstrate.

Secondly, pdt cosine r is the velocity which the vis mo-
Irix p would liave impressed upon m in the directioDj of 7/,
if this body had been free ; besides, V cosine y being the
velocity of m in the direction of ^^, d (V cosine y) is the
quantity which this velocity estimated in the same direction
auiiments : therefore pdt cosine r -^ d (V cosine y) is the
velocity lost by m in the direction of 2i, in virtue of the re-
ciprocal action of the bodies : it is therefore this quantity
which we must put for U cosine z in the second equation (F),
which becomes by this substitution s mup d t cosine r —
smu d {Si cosine y) = 0, which is the second of the twa
equations we had to demonstrate.

These equations are therefore nothing else than the fun-
damental equations (E) and (F) applied to the case where
the movement changes by insensible degrees, and therefore-
thev contain all the laws of this .movement : we may re-
mark also, that the first of th^se two equations is only a par-
ticular case of the second, for the same reason that the
equation (E), whence it is extracted, is contained in that
(F) whence the second is extracted. Bui this first equation
s mV p d t cosine \{ -- s mV dV = 0 deserves particular
attention; because it contains the famous principle of the
preseiration of active forces in a system of hard bodies the
movement of which chanirei bv insensible degrees : thus ;

Let

On Machines in Genei'aL 319

Let us first call d s ilie element of the curve described by
the corpuscle m during d t ; this being done, we shall have

V d t — d s f and therefore the preceding equation assumes
this form smpd s_ cosine R — 57?iVt?V = 0. Now let us
suppose for a moment that the curve described by m is an
inflexible line, ihat m is a. moveable grain interwoven with
this curve, that it traverses it freely, i, e. without being
pressed by the re-actions of the other parts of the system,
that it experiences at each point of this curve the same
vis motrix as that with which it was animated in the first
case; and that, finally, in this first case the initial velocity
of w is K, while in the second it will be null at the first
instant, and V'' after an indeterminate time / ; this being
done, by integrating the preceding equation, in order to
have the state of the system at the end of the time /, we
shall have for the first case s' s m p d s cosine R — 5' 5 m

V c? V = 0, s' designating the sign of integration relative
to the duration of the movement, while s is the sign of in-
tegration relative to the figure of the system : no\v_, s' s m

s mV^ .

V fi V = • therefore the equation may be placed ia

jt

this form s' s m p d s cosine R — 5 ?» V* -f C = 0 ; C

being a constant added to con)plete the integral : in order to

determine it, we shall observe that at the first instant we

have V = K and s' s m p d s cosine R = 0 ; therefore

smYJ-
C = — - — 5 therefore Is' s m p d s cosine R — 5 tw V*

s mYi} = 0 : by the same reasons we have for the second
case 2 s' s m p d s cosine R — 5 ?« V' * = 0, without a con-
stant, because we suppose V' as null at the first instant:
taking away therefore this e<juation from the preceding one,
reducing and transposing, we have s m V- •=■ s m }L- -^ s m
V'*; that is to say, in any system of hard bodies the mtve-
ment of which changes by insensible degrees, the stnn of the
active forces at the end of arnj given time is equal to the sum
of the initial active forces, plus the sum of the active forces
ivhich would take place if each moveable particle had for its
velocity ihat which it would have acquired by freely traversing
iJie curve it had described, and supposing bendes that it had

bun

320 On Chemical Nomenclaticrc,

ieen animated at each point of (his curve, with the same vis
matrix which it there really experiences^ and that' its velocity
at the first instant had been null.

It is this proposition which we call the principle of the
preservation of active forces ; and whence we may conclude
that,

In a system of hard bodies the movement of which cJmnges
ly insensible degrees ^ and which are not animated with any
vis motrix, the sum of the active forces is a constant qtian-
tity, i. e. the same for eve^-y instant.

For in this cas-e we have by hypothesis p = 0, which
gives V = 0, and therefore 5 ?« V^ = 5 m K- ; an equation
besides which is extracted immedialely from that smpV dt
cosine R — 5mV€?V=0, found in XXIV^ which, on
account of p = 0, is reduced to s w V £? V = 0, the integral
of which completed is \ s m Y^ r=. \ s m YJ- =05 whence
follows the equation j; w V^ = ^ m K-. a. E. D.

[To be continued.]

LX. On Chemical Nomenclature, By a Correspondent.
To Mr, Tilloch.

SIR,

J. HE importance of an accurate and scientific nomenclature
being now admitted by every lover of chemistry, 1 shall
make no apology for suggesting what I consider an improve-
ment. The metalline salts are named after a plan which
is extremely defective. It proceeds upon the supposion that
no more than two oxides of any metal can combine with
the same acid. The salt whose base is the first of these
oxides is named as if there were no oxide present : thus,
the protoxide of iron and sulphuric acid form what is called
sulphate of iron. On the other hand, the salt which con-
tains the second of these oxides is known by oxy being
prefixed, as in the oxy- sulphate of iron.

This mode of nomenclature is objectionable on several
accounts.

1.3t, It is extremely deficient in tbe extent of application.

as

On Chemical Nomenclature. 321

as it makes not the least provision for those metals which
combine with three and four proportions ot" oxygen ; conse-
quently there are no names for those salts which contain
oxides intermediate between the minimum and the maxi-
mum. For instance, late experiments have shown that no
less than three oxides of iron combine with the sulphuric
acid. The first of these combinations is called sulphate of
iron, the last is called oxy- sulphate ; and for the second
therq is no chemical name.

2dly. It is evident that great confusion must arise from
the want of some di^^tinction between a superfluity of
oxygen in the acid, and a maximum in the base. Am I
to suppose that the oxy-prussiate of iron is the peroxide
combined with prussic acid ; — or must I conclude that it is
the nictal in an inferior degree of oxidation combined with
oxy-prussic acid ? Indeed, by pursuing the present nomen-
clature, we may soon expect to hear of oxy-oxy-prussiates
and oxy-hyper-oxy-muriates, when there are at the same
time an excess of oxygen in the acid and a maximum in
the base.

3dly. When any metal has more oxides than two, the
present nomenclature leaves us totally unable to distinguish
the particular oxide united to the acid. Thus any one would
suppose that the nitrate, sulphate and hyperoxymuriate of
letid, each contained the same oxide base ; yet we find these
.salts severally containing the prot-, deut-, and per-oxides.

In short, to these capital defects in nomenclature I ascribe
the slow progress which has hitherto been made in our
knowledge of the metallic salts, and I conclude that some
improvement is absolutely necessary. That which I would
suggest has at least the advantage of clearness and sin)plicity.
I would carry into the nomenclature of these salts, Doctor
Thomson's mode of designating the metallic oxides. For
nitrate of lead, I would say nitrated protoxide of lead; and
for oxy-nitrate, I would say (if such salts can be formed)
nitrated deutoxide, tritoxide, or peroxide, according to the
degree in which the metal may happen to be oxided. By
this cliange every possible variety of these salts is provided
vith a name, ck*arly distinguishing tfie decree to which the

Vol. 30. No. 120c May 1608. X baic

3i22 On the Manufactures carried on at Bangalore ,

base is oxided, and totally free from all the obscurity of the
method now in use. Yours, E. B.

P. S. As Mr. Davy's late experiments hold out to us the
prospect of decomposing several substances hitherto ranked
with simple bodies, I would beg leave to suggest the pre-
priety of adopting names for them as nearly as possible allied
to the nomenclature in use. I would call the base of the
muriatic acid, muria ; that of the boracic, borax ; and that
of the fluoric, fluor. We should not object to these words,
that they w''l be unmeaning in their new application, and
that same of them have been used before to signify other
substances. We should recollect that words are only the
signs of thlirgs, and possess no other relation to them than
that which is derived from custom : we should also remem-
ber, that the words borax and fluor, though formerly vised,
are no longer chemical terms, and may therefore without
impropriety be applied to any new substance. Upon this
principle, I have always lanw^nted that the base of nitric
acid was not called nitre, iiastead of azote or nitrogen ; for,
if the acid were named regularly after cither of these, it
would be the azotic or nitrogenic, and not the nitric, acid.

LXJ. yksotiut of tJte Manufactures carried on at Bangalore y
and the Processes employed hy the Natives in Dyeing Silk
and Cotton,

[Concluded from p. 272.]

Jl he weaver* of Bangalore seem to me to be a very In-
genious class of men, and, with encouragement, to be
capable of making very rich, fine, elegant cloths of any
kind that may be in demand : but, having been chiefly ac-
customed to work goods for the use of the court at Seringa-
patam, they must now labour under great disadvantages ;
for it never can be expected that the court of Mysore should
equal that of Seringapatam, nor will the English officers
ever demand the native goods so much as the Mussulman
iirdars did. The manufacturers of this place can never,
therefore, be expected to equal what they were in Hyder's
6 reign^

and the Processes used for Dyeing Silk and Cotton. 323

l^eign, unless some foreign market can be found for the
goods. Purnea, very desirous of the re-estabhshment of
this city, has forwarded by me the musters of cotton and
silk cloth that accompany this account, with a request that
they may be presented in his name to the marquis Wel-
lesley : and I beg leave to recommend, that the attention of
the hoard of trade may he directed to them, with a view of
forming some commercial arrangements that may assist in
restoring a country which has suffered so much.

The silk manufacture seems especially favourable for a
country so far from the sea and from navigable rivers ; as
long carriage, on such a valuable article, is of little import-
ance. At present all the <raw material is imported : but I
see no reason why it might not be raised in Mysore to great
advantage. Tippoo 'had commenced a trial ; but his arbi-
trary nlbasurcs were little calculated to ensure success. Some
of the mulbcxry-trees, however, that remain in his gardens
show how well the plant agrees with this cllnjate. It is
true, that the experiments hitherto tried below the Ghauts
have not been favourable : but much resolution and patience
are always required, to introduce any new article of cultiva-
tion ; and I suspect that the climate here, owing to its being
more temperate, will be found more favourable than that of
the lower Carnatic.

There is a small duty levied here on every loom ; and it
is judiciously diminished to those who keep many, in order
to encourage men of wealth to employ their capital in that
way. A man who has one loom pays, annually, 3\fanayns
{^s. Q\d,) ; two looms pay 5 fanams (3s, 4|£/.) ; and a man
who keeps more tl^an tvvo looms pays only ibr each two
fanauiSy or Is, Ad. All shopkeepers pay similar trifling
duties.

There is here a set of people called Rungani, who act as
tailors, cloth printers, and dyers. Their printcJ cloths ar«
very coarse^.aad.the art among them is in a very imperfect
stale. The onl) iwo colours th^t they can give in printing
are red and black.. Their process is as follows :

The cloth that is to be printed is kept all night in a mix-

X 2 ture

32-i On the Manufactures carried on at Bangalore,

ture of sheep's dung and water. Next morning it is washed,
and then bleached the wliolc day in the sun, having water
occasionally. At night it is again put into a mixture of
5hcep*s dung and water, to which is added a little quick-
lime. Next morning it is waslicd again, and then put into
a cold infusion of arulay jnyrohalans, [terminalia arulaj
Buch. MSS.) mixed with some gum of the dinduga tree,
{Andersonia Panchmomn^ Roxb. MSS.). The quantity of
myrohalans for 12 cubits of cloth is 6 dudus weight (2-i*o-o%
ounces), and of gum two dudus \\Q\ghi (IG-^Pyi^^^ drachms).
The cloth, after being thoroughly wet in this, is taken out,
and dried in the sun. It is then folded, placed on a smooth
plank, and well beaten with a stick, which serves instead
of mangling.

The mordant for the red dye is as follows : Dissolve in
one seer (68 cubical inches) of hot water, 0 dudits weight
(2^4^^-6_ ounces) of alum, and \-2dudus weight {^\-^^^ ounces)
of dinduga gum. This mordant is poured into a cavity that
is made in a block of timber, and covered with four folds
of country blanket wcU'moistened wiih the dinduga muci-
lage. The wooden blocks for printing are moistened with
the mordant, by applying their surfaces to the blankets. The
cloth to be printed is laid on a table covered with four folds
of old cloth, and the blocks are applied, and pressed dowu
by the hand. It is then kept for eight or ten days.

If the printer wishes to add black to the pattern, the
cloth must be again printed with the following mordant.
Take 5 seers (3y%3jvlbs.) of iron dross, and 5 seers of old
iron, put them into a pot containing rather hiorcthan two ale
quarts (2-i- seers) of hoi ka.7iji, or decoction of rice; then add
half a seer {^i-^^^^^^omiCQs) of sugar-jagory, and keep it six
or seven days. Next add half a seer of dinduga gum rubbed
up with a little ghee (boiled butter), and allow it all night
to dissolve : the mordant is then fit for use, and is applied
in the same manner as the other. After this the cloth re-
quires only four days to dry.

After the mordants have been dried on it, the cloth must
be taken to the tank, washed very well, by beating it on a

tStone

and ike Processes used for Dyeing Silk and Cotton, 325

tiXone for an hour, and then dried. In order to give it the
colour, put a piece, that has received the mordants, into a
pot, with 20 seers (about five gallons) of water of the kind
called here salt, one half seer of popll bark, and one diidu
weight {6j>o\ro drachms) of castor oil ; then boil it for two
hours, all the while carefully stirring the whole. The cloth
is then taken out, and dried in the sun. At night it is
soaked in a mixture of sheep's dung and water, next morn-
ing washed, and then bleached all day. At night it is again
put into the mixture of sheep's dung and water, and next
day is again bleached. The operation is then finished by
starching it with Jiavji. The black is a fixed colour, but the
red is perishable.

With the pa/W77^fi wood these Rungaru dye cotton cloth
of a red colour, which is bright, but does not stand wash-
ing. It is said that the people of Madras have the art of
fixing it. The process used by tli£ Rungaru is as fgllows :
Prepare the cloth by soaking each piece in a seer of water,
containing six diuh/s weight of powdered myrolalajis. Then
dip it into two or three seers (about two quarts) of a decoc-
tion of patunga wood, in which have been dissolved two
diidus weight of aUun. Then dry the cloth in the sun. The
operation must be repeated four or five times, until the co-
lour be deep enough. The decoction of paiunga is made as
follows t Beat two seers (It^oVM^s*) of patu/iga wood, put it
into a pot with 20 sccjs (about 5 gallons) of water, and boil
for six hours.

'Jlie Niligaru are another class of dyers, of the same cast
with the potmakers, and derive their name from their dyeing
with the iiilaox indigo. The whole of this dye that is used
here comes from the lower Carnati^:, or northern CIrcars. In
order to make a vat, the Niligaru take ten seers (fi/uVo'^s.)
of indigo, ground with a little water to a fine powder ; put it
into a pot capable of containing 50 seer^k measure (or a little
more than 12 ale gallons) ; and add a decoction of to gasliay
lijay or seed of the cassia torn, which is made as follows:
Take 4 seers measure (t^^oV Winchester gallon) of the seed,
and boil it for 6 hours in four or five seers of water (about an
;ale gallon). The boiled seed, as well as the decoction^ must

X3 be

326 On the Manufactures carried 07i at Bangalore,

be put into the vat ; and then there must be added 10 secr^
(6yVirg-lb.) of powdered soiduj or impure soda, 12 setrs
(7tVJ^0 of quicklime, and two seers of ihe ley of pot-ash
(137 cubical inches). The whole is then stirred with a
stick, and the mouth of the pot is covered up. Every even-
ing and morning, for four days, three seers (206 cubical
inches) more of the icy must be added ; and in the last por.
tion must be put about the size of an apple of quicklime.
The vat now rests for three days ; when four or five seers of
boiling waier must be added to it, and the vat is then ready
for dyeing. The ley of potash is prepared as follows : Burn
to ashes the branches of the ctf//i {euphorhmm tirucalli), or
of the titrayena {achyranthes muricata) : of these ashes put
2 seers (I iVo-o^^-^ ^^"^^^ ^ P°^ ^" ^^^ bottom of which there
IS a small hole. The hole is covered with a small inverted
cup, and that by some rice husks or chaff. Above these
are put the ashes, and on them are poured by degrees 23
seers, or about 6 ale gallons of water, which filters through
the hole in the bottom of the pf)t, and forms the ley. It
must be observed, that the water used by the Niligaru is al-
ways either that called here salt; 6r that which is found in
places abounding with calcareous tttffa.

The indigo vat having been prepared, an estimate is
formed of the number of seers weight of cotton that it will
dye. For every seer weight of cotton thread pass a seer
measure of water through the pot containing the ashes, and
in this weak ley dip the seer of cotton ; wash it well, and
then wring out the water. The solution of indigo is then
divided into five equal parts. The thread is dipped, by
seers weight at a time, into these pots, till the colour in
each is exhausted ; and what does not obtain a proper co-
lour in the first, after being dried, receives repeated dips,
until the colour arrives at the required intensity. The so-
lution of indigo is kept for a month, and every night a little
lime-water is added : this enables it to give some more co-
Jour, which next day is again exhausted by dyeing some
more cotton. The colour given by one dip is called mavi,
and is a sky-blue ; that which is given by five dips in a
strong pot, is of an intense colour, nearly approaching to

^ ^ blacky

and the Processes used for Dyeing Silk aTid Cotton. 327

black, and is in fact called black by the natives, among
whom it is in great esteem.

From (he weavers the N Hi gam receive cotton, and silk
thread dyed yellow with turmeric, and return it to them ol
a green colour, which it obtains by a dip in a weak pot.

At Bangalore, as well as in all the neighbouring country,
goni is a considerable article oF manufacture. It is a coarse
but very strong sack-cloth, from IS to £2 cubits in length,
and from \ to I- of a cubit broad ; and is made from the
janupa, ov crotalariajuncea. It is divided into three kinds,
which differ in value according to their strength and to the
closeness of the fabric. The same people, who are a par-
ticular cast of i33en, cultivate the plant, ami carry on the
manufacture, until the go7ii be fit for sale ; the price of the
hemp cannot therefore be ascertained, as it is not sold in
that state. The gojii-maker hires from some farmer as much
high ground as he thinks will raise a quantity i\^ janiipa suf-
ficient.to employ his family to manufacture in one year.
The soil ought to be red or black, like the best kinds used
for the cultivation of ragy. It is allowed no manure ; and
the seed is sown broad-cast on th-e ground, without any
previous cultivation, at the season when the rains become
what the natives call male, that is to say, when they be-
come heavy. After being sown, the field is ploughed twice,
once lengthwise, and once across ; but receives no further
cultivation- At other times the jafmpa is cultivated on rioe-
ground in the dry season ; but it must then be watered from
a canal, or reservoir. It requires four months to ripen,
which is known by the seeds having come to full maturity.
After being cut down, -it is spread out to the sun, andxlried.
The seed is then beaten out by strikingthe pods with a stick.
After this the stems arc tied upin largx? bundles, about
^wo fathoms in circumference, and are prese,rved in stacks^ .
or under sheds. The bundles are taken out as wanted,
and put in the water, at which time their bands are cut, and
the stems being opened out are kept down to the bottom
by stones or mud. According to circumstances, ihey re-
<^uire to be kept in the water from six t() eight days. They
^r^ known to be ready, when the bark separates easily &oa>

X4 . "the

328 On Ihe Alanufaciures carried on at Bangalore ,

the pith. It is then taken out of the water, and a man,
taking it up hy handfuls, beats them on the ground, oc-
casionally washes them until they be clean ; and at the same
time picks out ivith his hand the remainder of the pith, un-
til nothing except the bark be left. This is then dried, and,
being taken up by handfuls, is beaten with a stick to sepa-
rate and clean the fibres. The hemp is then completely
ready, and is spun into thread on a spindle, both by the
men and women. The men alone weave it, and perform
this labour in the open air with a very rude loon).

Leather is tanned here by a class of people esteemed of
very low cast, and called Madigaru, -

To dress the raw hides of sheep or goats, tlie Madigaru in
the first place wash them clean, and then rub each with the
fourth part of a kind of soft paste, made of 6 dudus weight
of the milky juice of the yccada {asclepias gigantca), about
() dudus \\c\^-\t (2-j-*^f-j/'g- ounces) of salt (nmiiate of soda),
and twelve dudus weight of ragij savguty, or pudding of
the cynosurus coracanus, with a sufficient quantity of water.
This paste is rubbed on the hairy side, and the skins are
then exposed for three days to the sun ; after which tl)ey
are washed with water, beating them well on a stone, as is
usual in this country. This takes off tlie hair. Then pow-
der 2 seers (nVdV^t).) of arulay myrolalans^ and put them
and one skin into a pot with 3 or 4 seers measure of hot
water, where it is to remain for three days. 'Jlie skin is
then to be washed and dried.

This tanned skin is dyed black as follows : Take of old
iron, and of the dross of iron forges, each a handful : of
plantain and lime-skins, each fiv^e or six ; put them into a
pot with some ragy kanjiy or decoction of ragy^ and let tiicm
stand for eight days. Then rub the liquor on the skins,
which immediately become black.

These skins may be dyed red by the following process :
Take of ungarbled lac 2 dudus weight (about 13 drachms),
oi' suja caray or fine soda, 1 dudu weight, and o^ lodu bark
2 dudus weight. Having taken the slicks from the lac, and
powdered the soda and bark, boil them all together in a seer
of water (68|- cubical inches) for J -.^ hour. Rub the skin,.

after

and the Processes used in Dijewg Silk avd Cotton, 32^
after it has been freed from the hair as before mentioned,
\vith this decoction ; and then put it into the pot with the
tnyrohalans and water for three days. This is a good co-
lour, and for many purposes the skins are well dressed.

The hilJes of oxen and buffaloes are dressed as follows :
For each skin take 2 seers (ItVoM^O ^^ quick -lime, and 5
or () seers measure (about J-j ale gallon) of water ; and iii
this mixture keep the skins for eight days, and rub off the
hair. Then for each skin take ten seers, by weight, (al>out
6 lb.) of the unpeeled sticks of the iayvgadu {cassia auriai-
lata), and 10 seers measure of water (about 2^ ale gallons),
and in this infusion keep the skins for ft>ur days. For an
equal length of time, add the same quaniity of taijngaduand
water. Then wash, and drv the skins in the sun, stietching
them out with pegs. Thi^ leather is very bail.

The oil-makers at Bangalore are a very considerable chss
of people, and are of the kind that use two bullocks in their
mill, of which a drawing is jriven (Plate VIII *). The mortar
is a block of granite. This class of people are called Jotypha-
7iaday or Jotynagnrada Ganagaru. They express ihe follow-
ing kinds of oil : wuli'-ellu, Jmts*-dluy haralu^ cohri^ ip^yx
and hoiiigay.

, The wjiW-ellu oil is expressed frou] two varieties or
species o^ sesarnum seed, called here suruiianrt nuCi cari ellus.
They are the same with the wnllay and phnlugana ellus of
Scringapatam. The first gives the least oil; but for the
table it is esteemed the best of any in the country : the
price, however, of the two kinds is the same. T^.e mill re-
ceives at one time about seventy seers measure (2-p\*g- Win-
chester bushels) of sesamum seed ; and, in the course of
grinding, ten Cuclia seers measure of water (S^oV ale quarts)
are gradually added. The grinding continues for six hours,

* A, A, (Fig. 1 and 2) the mortar, J feet G inches outside measure from
rt to h. The inside cavity is L' feet wide. The heig-ht from the p^round to
the top of the mortar is 6 feet 3 inches from the ground, and the block of
which it is made descends into the earth G feet i) inches. The pestle B, B,
IS 5 feet 1 inch in length. The cross hH.ndle of the pestie C, is 'S feet 7 incites
long, by whicli, with the help of a cord, the pestle is attached to the post D,
4 feet 8 inches long, fastened into the beam E, F, which measures Jg feet
Ifom £ to G, and 5 feet 5 inches from G Co F.

•svhen

330 On the Manufactures carried on at Bangalore, &c,

when the farinaceous parts of the seed, and the water, form
a cake; and this having been removed, the oil is found
clean and pure in the bottom of the mortar, from whence
it is taken by a cup. Seventy Pucka seers (^y%\ Win-
chester bushels) of surugafiaf or 65 seers of cari-ellu seed
(^tVoV Winchester bushels), give 2 ,Cucha maunds (rather
more than 54. ale gallons) of oil. The mill requires the-la-
hour of two men and four oxen, and grinds twice a day,
Thu oxen are fed entirely on straw, and are allowed none of
the cake ; which is sometimes dressed with greens and fruits
into curry, and at others given to milch cattle.

The huts' 'cllu is managed exactly in the same manner as
the sesamum. The seventy seers measure require a little
more water than the other ellu, and give 65 seers of oil (or
a little more than 4^ gallons). This also is used for the
table. The cake is never used for curry, but is commonly
given to milch cattle.

The harulu, or castor oil, is made indifferently from
either the lart^e or smiill varieties of the ricinus. It is the

o

common lamp oil of the country, and is also used in medi-
cine. The oil made by boiling is only for family use; all
that is made for sale is expressed in the mill. To form
the cake, seventy seers of the seed require only five seers,
Cucha measure (ItV^ ^^^ quarts), of water, and give 60
seers (4VoV ^^^ gallons) of oil ; which, after being tak^ii
out of the mill, must be boiled for half an hour, and
then strained through a cloih. The cake is used d,5
fuel.

Coh'i oil is that made from the dried kernel of the coco-
nut, which is called colri. This oil is chiefly used for
anointing the hair and skin. Cakes are also fried in it, and
it is sometimes used for the lamp. The mill receives 6
maunds weight of the cobri (almost 93 lb.), and 1 1 Cucha
seers measure of water (a little more than 3 ale quarts). This
produces three maimds (about 7-/o ^^^ gallons) 'of oil. The
natives eat the cake dressed in various ways.

The ipay oil, made from the fruit of the hassia longifolia,
is used for the lamps burned before the gods, being esteemed
of a better quality than that of the ricinus. The mill takes

70 seers

Description of the Bermuda Islands , &c. 33t

70 seers measure, and the seed requires to be moistened
with 12 Cucha seers (34- ale quarts) of tamarind water, in
which 2 seers of tamarinds have been infused. The produce
is 70 seers (4-^^^^^ij' ale gallons) of oil. The cake is used as
6oap to wash oil out of the hair of those who anoint them-
selves.

The lioingny oil, produced from the seed of the robinia
mitis, is used for the lamp ; but it consumes very quickly.
It is also used externally in many diseases. Take 70 seers,
Pucca measure, of the seed freed from the pods, add 4 Cucha
seers measure of water (ixVo- ale quart), and beat them in a
mortar into a paste. Then tread the paste with the ieet;
and, having kept it for two or three days, dry it in the sun.
It is then put into the mill with one Cucha seer (19-jeg. cubi-
cal inches) of water. It produces 40 seers (2f ale gallons)
of oil. For fuel, the cake is mixed with cow-dung.

The English weight, to which all the native weights are
reduced^ is the pound avoirdupois.

LXII. Descriplion of the Bermuda Islands, and particularly
the Island of St, George. Addressed to the Directors of
the French Museum of Natural History, by M,A. F. Mi-
CHAUX, temporary Jgmit of the French Imperial Ad-
ministration of IVoods and Forests in North America'^,

X EMBARKED at Bourdcaux on the 5th of February, 1806,
for the United States; my voyage having for its object to
collect and transmit to the administration in the department
of woods and forests, a great quantity of seeds and plant*
of sucli forest trees as might be naturalized in Franco, or
succeed in those uncultivated districts where our own indi-
genous trees refuse to grow. On the 23d of March the
American vessel, on board of which I was, fell in with the
I.eander, an English man-of-war, commanded by captain
Whitby, who, suspecting our cargo to belong to French
jnerchants_, sent the ship to Halifax, in Nova Scotia. I

* From Annalcs du J^lnsvum d'HisioiTe NaturelUi tome viit. p. 355.

-was

632 Description of the Bermuda Islands,

"Was the only one of all the passengers who was ordered on
board the Lcander, where I remained for 43 days, during
which time the cruize lasted. This disagreeable event re-
uioved me more than 600 leagues from Charlestown ; but it
gave me ait opportunity of visiting the Bermuda Islands,
where the Leander anchored on the 7th of April, to take in
water. We remained there eight days, and I obtained per-
niission from captain Whitby (who always treated me with
the utmost politeness) to go on shore frequently : upon
these visits I made the observations I am about to com-
municate*.

The number of islands composing the Archipelago of the
Bermudas is so considerable, that the inhabitants say they
are equal to the days of the year. The largest are only from
12 to 13 miles long, The smallest look l,ike lime rocks just
rising above the surface of the sea. The whole occupies an
extent of about 35 miles in lent^th by 20 or 25 broad. To-
wards the north himiense strata of rocks extend from 30 to
40 miles, rendering the approach of vessels dangerous.

These islands, although much lower than tht^ Azores,
present nearly th^ same appearance at a distance,, and re-
semble long and high ridges of hillocks covered with a
darkish verdure. They are not surrounded by ^ t^at and
sandy beach like the Floridas, but skirted by high rocks,
against which the waves are continually breaking.

The island near which the English ships of war generally
anchor is called St. George's, which is also the name of the
chief town. The town of riamilton is in another island,
ilfteen miles off; these two arc tht^ only towns in the Ber-
ynudas. There are no bouses so close together in any other
place as to entitle them even to the name of villai^es.

St. George's island is situated at the north end of the
Archipelago, and it was the only one on which I landed.
It is of the second class in point of size, being nine miles
long by three broad in sonie places, and only a quarter of a
mile in others. The straights, which separate its southern
shores from the islands of St. David, forni the harbour, and

* M. Michaux was liumantly released at Halifax, by captair^ Whitby,
^nd prDccedcd to New York.— i'V*/jr/t Editor,

its

and paTtlculdrly the Island of St, George, 333

its entrance is strongly barricadoed by the projecting point
of another island. It is edged round with blackish rocks,
varying in height from 5 to 25 feet. When viewed at a
distance, these rocks resemble a long hillock, the inequali-
ties in which constitute so many small valleys. Upon the
heights the soil is dry and sandy, and frequently ihe bare
rock is seen : in the low grounds, on the contrary, the earth
15 a brown clay slighily moistened, and its vigorous vegcta*
tion announces its extreme fertility.

Three fourths of the island are covered Vvlth wood ; the
rest is partly cultivated, or so barren that it is not suscepti*
ble of cultivation.

The plants peculiar to the island arc few in number : and
although my journeys through the island were very rapid,
I think I may safely affirm that the number of species does
not exceed 140 or loO. Among these plants we find seve-
ral bclonffincr to the antient continent, which do not sccni
to have been of a nature to occasion them to be tran.-jplantcd
here : these are, the verbascum thapsus, anagaUis arvensis,
mcrairialis annua, leontodon taraxacum^ pUnitago major,
urtica urcns^ gcntiana nana, oxalis acetosclla, Sec. We
also find here the great cabbage palm tree, chamccrops pal-
meto^ and the rhm toxicodendruvi of North America. As
to other plants, I could only ascertain a small number of
them ; but I collected seeds of all those which had been
preserved the year before, among others a strawberry plant,
the aromatic flowers of which resemble sage, and it is on
this account called sage-bask by the inliabitants ; a beautiful
species of veibcna, and a small medicago, each foot of which
scarcely occupies an inch of ground ; this is ihe most com*
nion plant in the country, forming almost the whole of the
verdure every where; the surface of the ground not beintr, as
in Europe and the United States, covered chieHy with the
grasses, of which last there are very few kinds in the Ber-
mudas.

The juniperus Bermudiana, called by the inhabitants ce^
dar, is the only forest tree in these islands : the whole arc
nearly covered vviih them ; and it is this tree which, when
seen in clumps at a distance, gives a dull and sombre ap-^

pearance

S34 Description of the Bermuda Islands,

pearanco to the islands. It grows throughout the whole
island, in every kind of exposure ; but in the valleys its ve-
getation is more vigorous than upon the summit of the
hills, and the primordial branches .attain to a great height,
its elevation does not exceed 40 or 50 feet, and its diameter
is from a foot to 15 inches. Although the branches have a
tendency to expand from the trunk, those of the full-grown
trees touch each other ; which may give an idea of the di-
stance at which they are placed. Upon the heights, and in
places which having been recently laid bare are replenished
with young trees from the seeds of the old, one fourth of
the young trees forms a thicket ; the branches shoot out
very close to the earth, and extend eight or ten feet around
the parent tree.

These cedar trees are not felled at any regular season i
they cut down a tree whenever they think it of a sufficient
size for their purpose, leaving it to nature to till up the va-
cancies made by these occasional removals ; and to this im-
providence may in a great measure be ascribed the high
price to which the wood of these trees has risen.

It was the tlourishing season when I was at the Bermudas.
The female trees were discernible at the distance of 15 or
20 paces by the darker colour of their foliage : the seeds
are ripe about the end of October, but they fall during win-
ter; so that I could find only a very few upon the trees.
I am very anxious to see them cultivated, and have no
doubt that this tree woidd be a valuable acquisition, either
for the island of Corsica, or for some parts of our de-
partments of the South near the Mediterranean. They make
a syrup of these seeds, said to be extremely useful in cer-
tain pulmonary complaints.

Thtjimiperi/s Bermiidiana is very much esteemed, bn ac-
count of the quality of its wood * ; it is fine grained, com-
pact, and more resinous than the jjiniperus Virginiana. As
in the former species the sap is only five or six lines thick in
a tree of 1 2 or 14 inches diameter, this wood is employed

* We may judge of its colour and smell from the black lead pencils called
English crayons : the juniper tree of the Bermudas and that of Virginia are
equally employed in their fabrication.

in

and particularly the Island of St, George, 335

in building sloops, which has been the principal branch of
the industry of the Berraudians for a long period. These
vessels are remarkable for their quick sailing, and last
for a long time. It is said, however, that they are more
liable to go to pieces than oak vessels when they strike.
Six luggers, or cutters, from 120 to 140 tons, and copper-
bottomed, have been built at the Bermudas by order of the
English government.

The cedar tree is the sole riches of the inhabitants ; and
the fortune of every individual is estimated by the number
of trees he possesses. They are sold on the ground at a gui-
nea each.

1 was told there were no quadrupeds natural to the coun-
try. The only birds I saw in the woods were, the cardinal,
loxia cardinaliSy and the blue bird, motacilla sialis, which
they say belongs to the continent of North America.

Every year, in the months of March and April, the Ca-
chalot whales approach very near the shores, where some of
the inhabitants, but particularly the men of colour, fish for
them.

The shell-fish which are most common belong to the
genera of turbo, donax, and mytilla. The latter are very
abundant, and arc only 5 or (> lines long.

Agriculture, which is now entirely neglected in the Ber-
-mudas, once flourished there, as is proved by the records
of the custom-house, which mention the quantity of sugar
and wines annually exported from the colony. The present
inhabitants employ the small number of negrf>es they possess
in cultivating pot-herbs and maize, and in feeding poultry.
They have very few cattle or horses, and I saw only about
a dozen cows on the island, which were deriving a scanty
maintenance from the medkago 1 have mentioned. In the
country there are enclosures which might form a better sort
of pasturage, but they are all planted with cedar trees. ^ Pro-
visions of every kind are so rare, and so dear, thai the ships
of war which are constantly arriving at ilie Bermudas can
only procure potatoes and onions.

There is but one kind of stone in the island, which i»
found in great abundance a few feet below the surface.

Upon

S3G Description of the Bermuda Llands, ^c.

Upon coming out oF the quarry it is very white, and so ten-
der that it may be reduced to powder between the fingers;
uhcn exposed to the air it becomes of a deep gray and in-
durates. When seen through the microscope it appeared
to me as composed of a very fine sand and of shells. Two
t]uarrics are wrought near the town, in each of which eight
or ten negroes or mulattoes are emplovcd, who earn from a
piaster to a piaster and a half daily. Their labour is easy :
the stones when detached from the mass are sawn into pieces>
of about one or two feet broad by six or eight inches thick.

Neither at St. George's island nor at any other of the
Bermudas are there any springs or rivulets, and experience
has shown that wells cannot be dug ; rain water, therefore,
is alone made use of, which, from the precautions used, is
not only sufficient for the inhabitants, but also for supply-
ing the ships of war which put in there for the purpose.

About 100 yards from the sea, there are constructed
upon an inclined plane two immense terraces of a triangular
form, destined to receive the rain water, which flows into
cisterns, around which the empty casks are rolled, and lillcd
by means of hand pumps.

The walls of these terraces are of mason work ; and al-
though each occupies a space of 450 or 500 fathoms, they
are not always sufficient for the &up[)ly of the shipping.
The distance of these government cisterns Irpm the town is
about a mile. The road to them is eight or ten feet broad,
and is shaded by cedar trees. vShips of v\'ar of the first and
second rate cannot enter the harbour, but arc anchored one
or two miles off.

The town of St. George's has only 'ibO or 300 house?. It
is intersected by a dozen of narrow street? not paved, and
one of which only admits of a carriage to pass : the houses,
which mostlv consist ot only one story above the ground,
are generally coloured yellow. The wliolc are of stone, and
covered with tiles, with a gutter round the roof to receive
the rain water : this roof, which is painted white, reflects
the ravs of the sun so strongly as to be very injunous to the
eyesight.

Several houses have small gardens^ the walls of which

are

On Colalt and NickeL 337

are eovered with the cactus opuntia. The most common
pot-herbs, however, are alone cultivated in them. In some
I have sten the carica papaya, the melia azedarachf the La-
Tianier, and the geranium roseum and zonale.

We meet with very few people in the streets, and the in-
habiiants seem to be extremely indolent. There are only
live or six shops in the town, where spices, trinkets, and
cloths, are sold at a very high price. The Americans im-
port into the place planks, maize, flour, butter, and some
other provisions, for which they receive ready money. The
money of the country is the heavy piaster.

They estimate the population of the Bermudas at eight or
nine thousand souls. I do not know the proportion of
whites to negroes, but the latter are said to be more nume-
rous. The lower classes are accused of misleading ships in
stormy weather, in order to pillage those who have the mis-
fortune to be thrown on their shores ; and the Bermudian
pirates have always been proverbial for their barbarity.

These islands are said to be very healthy ;. which cannot
be doubted from their situation.

LXIIf. Facts upon which to found a History of Col alt and
NickeL J3y M.Proust. Extracted iy M.Chexilevil*^

1 HE sulphuric, muriatic, and nitric acids oxidize metals
in the same manner. There is a disengagement of hydrogen
with the first two.

Sulphates. — Of these there are two ; the one simple, an4
the other tripled by some neutral salt with a base of potash
or ammonia.

1st. The simple sulphate has a slightly pungent taste, a
little bitter, and somewhat metallic. Its crystals, not
voluminous, are heaped up sections of irregular octae-
drons : they are of a gooseberry red, unalterable in the air ;
they lose 42 hundredth parts of water upon distillation ;

•,From AnnaJes de Chimie, torn. Ix. p. 260.

VoK 30, No. li^o. May 1808. Y they

338 Facts upon which to found a History

they are then red coIaureJ and opaque. In this state they
can support a red heat without being decomposed, except
in those points at which they touch the retort.

2d. When we mix sulphate of potash with the fore-
going-, we obtain more vohmiinous crystals, which are
rhomboidal cubes. This triple salt is less soluble than the
simple 5 it only loses 0:26 of water upon distillation.

Carbonate, — The carbonate of potash gives from 0*40 to
0*42 of carbonate of cobalt with the simple sulphate. An
excess of alkali dissolves a great part of the precipitate.
Ebullition and cold water decompose this solution.

Oxide at the minimjim. — 100 parts of carbonate leave,.
after the separation of the water and carbonic acid, from
0*60 to 0*62 of greenish gr;iy oxide. In order to have it
very pure, we must charge the retorts as full as possible, and
heat them gradually. Without these precautions, we ob-
tain an oxide mixed with oxide at the maximum, which, in
this case, gives oxygenated gas with the muriatic acid, while
that which is pure does not give an atom of it.

The gray oxide is dissolved with effervescence in the nitric
acid, without giving nitrous gas ; when heated in the open
air. It 'becomes black immediately. We easily discover aa
oxide, some parts of which are raised to the maximum by
the application of a weak acid, which dissolves only the
minor oxide. Ammonia operates the same separation as
Thenaid remarked.

Oxide by Precipitation, — 1st. Some drops of nitrate of
cobalt, poured into boiling water with a little potash in it,
give a blue precipitate, which at last becomes red if the
ebullition be continued :. in this case a hydrate is formed !

2d. If we employ alkali^Jed water cold, the blue precipi-
tate is formed ; but in place of making a hydrate it passes
to the green, without the contact of the air being able to
obscure its shade : it preserves this colour after being dried»

3d. If v/e boil this green precipitate, while it is fresh, ia
water with a little potash, it becomes a reddish gray, and
does not change any more.

The weak aci^s, vinegar for instance, dissolve the first
' i • precipitate

cf Cobalt and Nickel, '^-'^ ^3§

precipitate totally : applied to the other two, they separate
black oxide from them. Lastly, the blue oxide does not
give any gas with the muriatic acid, while the green does.

From this we mfcwt coi>clude, that the blue oxtd^id oxy-
genated at the expense of tlie air contained in cold Hquids-,
and that the grec'n oxide is a mixture of blue oxide and black
oxide, M. Proust thinks nevertheless, that there is some-
thing more than a simple niixture ; for the blue and black"
colours would not give this shade of grass green, which,
distinguishes it from every other oxide. Nothing but a
true combination can yield a colour foreign to that of
its components, and Kirtder the action of the air from
elevating to the maximum the portion of blue oxide which
forms part of the greeii precipitate. In order to oxidize thi^
precipitate completely, we must dry it by means of heat, as
Thenard has shown.

The reddish gray precipitate, in the third experiment, is a
mixture of hydrate'and black oxide.

It is only the minirmim oxide that can be combined with
the acids : the green oxide is never obtained from any so-
lution, and cannot become the base of any saline combina-
tion.

Ammonia and Oxide of Cobalt. — ^The gray oxide put into
a well-closed flask, along with ammonia, communicates
to it a slight red colour, which does not become higher,
however long the flask is kept : this oxide is therefore but
very difficultly soluble in ammonia. But if the flas-k remain
uncorked the ammonia is very quickly coloured^ because it
attracts carbonic acid from the air. We mar operate this
solution in a very short time, by placing the flask in a
large bason, in which we put a salt of carbonic acid.

If we only saturate the Ammonia with acid, the solution
is that of the oxide in the carbonate of ammonia. If we
continue to make the carbonic acid pass, we obtain a solution
oi carbonate of cobalt in the carbanate of ammonia* Thiy
solution^ when kept in a flask full and corked, deposits cry-
stals of metallic carbonate j it abandons a part of them by
the addition of water : an excess of volatile alkali redissolves
this precipitate. We may make this solution \tiry speedily,
by throwing carbonate of cobalt into carbonate of ammonia.

Y2 If

$40 Fads upon which to found a History

If wc pivt pure ammonia upon carbonate of cobak in ex-
cess, this alters the ease eompletely. The carbonate of' co-
balt is divided into two parts : the one yields its acid to the
ammonia and becomes hydrate, which is precipitated to the
bottom of the vessel, while the portion not decomposed is
dissolved into alkaline carbonate.

Here we have already two kinds of ammoniaca) solutions
of cobalt. There is a third discovered by Tassaert, but in
general very little remarked hitherto. We obtain it by put-
ting hydrate well washed, or blue oxide, into a flask full of
ammonia and well closed. The solution is made in 24
hours. It is red like the former; but differs from them in
this respect, that if we pour a drop of it into boiling water,
blue oxide is immediately precipitated ; when we operate
with cold water we obtain green oxide. If ammonia dis-
solves the hydrate of cobalt, or the fresh blue oxide, more
easily than the gray oxide, it is because the two former are
in very minute division.

Distillation of the arnmoniacal Solution. — When we distil
the solution of carbonated cobalt, carbonate of ammonia
passes over ; the liquor in the end deposits an oxide at first
of a dirty green, but which afterwards becomes black. This
is a mixture of gray oxide and black oxide.

How happens this byper*oxidation ? M. Proust merely
states the fact, and abstains from explanation where data
are wanting.

Hydrate of Cobalt, — The crystals of sulphate, or of ni-
trate, thrown into a flask full of liquid potash, and im-
mediately closed, are there decomposed : a blue precipitate
is formed, which passes to the violet, afterwards to the red_,
by becoming hydrate.

If we boil hydrate with potash, the latter dissolves oxide,
and is tinged with a fine blue colour. This solution is de-
composed upon the addition of water. In the air the oxide
becomes black, and is deposited.

The hydrate is dissolved cold in the cafbonate of potash,
and tinges it red. The oxide is not dissolved.

The hydrate of cobalt is of the colour of a dead rose leaf:
Ihe acids dissolve it with heat, and without effervescence.

The hydrate is not decomposed by ebullition, either in

pure

of Cobalt and Nickel. 34 1

pure water or in alkalized water. It loses from 20 to 21 of
water by heat, and is reduced to very pure gray oxide.

It keeps very badly under water : when it is in contact
with the air it becomes black. The dry hydrate is better
preserved, but attracts carbonic acid.

When we throw crystals of sulphate into a flask full of
ammonia and immediately closed, they give a blue preeipi- ^
tate, which d(K?s not become red a« in the potash. M. Proust
asserts that the hydrate is formed, but that it is dissolved
in some proportion in ammonia ; so that it is the hydrate
which colours the solution, and not the simple oxide.

Valuation of the Oxygen in the minor Oxide. — 100 parts of
gray oxide, reduced with proper precautions in a closed
crucible, give 63| of metallic grains. The quintal of cobalt
seems therefore to absorb 19 of oxygen, in order to become
minor oxide.

Major oxide. — If we distil a nitric solution of cobaU,
black crusts are deposited upon the sides of the retort, ni-
trous gas is disengaged, and we obtain from 1 25 to 1 26 of
black oxide as the residue. Hence we may conclude, thai
the maximum of ihe oxidation of the cobalt exists about 25
or 26 in 100.

This oxide is not dissolved in the nitric and sulphuric
acids, except by losing the portion of oxygen which consti-
tuted its maximum.

It gives oxygen gas with the mtlriatic acid.
it is inso-luble in ammonia and potash.
The black oxide, heated for half an hour at the bottom
Df a crucible, again becomes gray oxide by losing its oxvgen;
we may then tinge the vitrescible matters blue.

Messrs. Proust and Thalaker found the black oxide at
Pavias, in a journey to Valentia. It is also found in cobalt
ores, which have been called vltrecus or Hack ores.

The carbonate and hydrate of cobalt is changed into black
oxide, by the contact of the oxy-muriatic acid.

The nitrous and sulphurous acids dissolve the black oxide,
and form with it nitrate and sulphate at the minimum.

Muriate of Cobalt. — The gray oxide is dissolved with heat
in an acid of 15°. The warm or cold solution is of a deep

Y 3 blue:

342 Fads 7ipG7i ivhkh to found a History

blue; it crystallizes easily ; the crystals arc blue; it is the
dc-hydratcd muriate. As soon as it absorbs huniidity it be-
comes red.

The muriatic acid at 15^ yields a great deal oF gas with
black oxide. This solution is green while it retains the gas;
but as soon as it has lost it, it becomes blue. The blue
traits of the muriate of cobalt, dried upon paper, are nothing
else than de-hydrated muriate. When they are green, it is
because the salt still contains muriate of nickel, which
tinges it yellow, and forms green with the blue.

Its Distillation. — When brought to a red heat in a luted
retort, those parts only which touch the glass are decom-
posed : the products then are muriatic acid in vapour, mixed
with oxygenated acid. The glass is tinged blue. The non-
decomposed muriate is sublimed, after being melted in gray
flaky flowers ; these undergo a kind of condensation, which
renders them insoluble in water for at least 12 hours. Lat-
terJy, they give a solution of common muriate.

Arsenil-c and Arseniatc. — Thearsenite of cobalt is -prepafed
bv pouring a solution of cobalt well diluted into a solution
of arsenlte of potash. W^ obtain a red precipitate, which
preserves this colour upon drying.

Character of the Ars-cnite, — 1st. Heated in a tube closed
at one end, it is decon^posed ; the oxide of arsenic is sub-
limed, and the glass is tinged blue.

2d. The nitric aeid dissolves it, and there is nitrous gas.
3d. The nmriatic solution is decomposed bv sulphuretted
hydrogen, which precipitates orpiment.

4th. Pure potash, with the assistance of heat, sets free
the blueoxide.

Arsenlate. — We obtain it by using arseniate of potash in
place of arscnite. The precipitate is red, like the arsenitc.

Characters. — 1st. Heated in the tul>e, it does not give
any sublimate; it becomes violet, without tingeing theglass.
2d. The nitric acid dissolves it without nitrous gas.
Sd. Its muriatic solution is not disturbed by the sulphu-
retted hydrogen until two hours after the mixture.

4th. Pure potash sets inx tlie blue oxide, and is combined
with the acid.

The

vf Cobalt and Nickel. 343

The red efflorescences which we find upon minerals con-
taining cobalt arc formed of arseniate. IM. Proust found
llie arsenite in the heart of some pieces only.

Hydro svlphnret ted Oxide. Siilpkiiret oj Cobalt. — The gray
oxide, the hydrate, and carbonate, take from water the sul-
phuretted liydrogen, and become hydro-sulphuretted oxide*
The latter is not dissolved in ammonia; it give? water and sul-
phnrous acid upon distillation. The remainder is sulphiiret.

The oxides when heated with sulphur become sulphuret.
Cobalt absorbs 40 per cent, of sulphur. The authoj h^s still
some doubts upon this subject.

Facts respeciiug the History of Nickel,

Nitrate, — 100 parts of metal dissolved in the nitric acid,
and distilled until perfectly decomposed, leave from 123 to
126 of greenish gray oxide at the viinimum. The nitric
acid cannot make this oxide pass to the muximum.

In order to ascertain the purity of the oxide of nickel,
we must dissolve it in the muriatic a<:id and heat it. If it
contains a littJe oxide of cobalt, ther« will be an extrication
of oxygenated muriatic gas : if it be pure, none will be dis-
engaged.

The gray oxide is dissolved in all the acids, and gives the
same solutions as the metals.

Nitrate at the min'minm. — By (tistilling the nitrate of
nickel with the same precautions as the nitrate of copper,
we obtain, as with the latter, a nitrate with excess of base,
which is insoluble in water, 100 parts of nickel give 142
of this nitrate : on deducting the 25 parts of oxygen ab-
sorbed by the aaetalj we have 1 7 parts of acid .fixed upon
this oxide-

100 parts of iry nitrate of nickel gave upon distillation
5^0 of water, and 25 of oxide : therefore 53 of acid. These
proportioniJ are not rigorously exact, because the last^ por-f:
tions of water are a little acid. •

Muriate of Nickel, — ^This is a gramilous crystallization of
an apple green, and very deliquescent.

The traces of this salt, when dried upon paper, are yellow.

Y 4 This

341 Facts itpon which tofcund a History

This muriate loses 55 of water. What remains is a yel-
low de-hydratcd muriate, which again becomes green in the
air, by aI)soibing water.

The dc-hydrated muriate, when fire is applied to it, does
not melt : those parts only which touch the glass are decom-
posed : there is then an extrication of simple muriatic acid
afid oxygenated acid : the salt not decomposed is sublimed
under the form of pearl-like flowers of a golden yellow.
These flowers in two days absorb Immidity, and become
green. The muriatic acid dissolves them with difficulty.

100 parts of muriate of nickel gave, by means of carbo-
nate of potash, from 61 to (52 of carbonate; which supposes
from 33 to 31 of oxide.

Sulphates of Nickel. — ^Th ere are two, the one simple and
the other potashed. The first crystallizes in hexaedral prisms
terminated by«an irregular pyramid ; the second in rhomr
boidal prisms.

The simple sulphate loses 46 parts out of the 100 of water.
The de-hydrated residue again becomes green on absorbing
humidity. When strongly heated for an hour, and at a
red heat, in a luted retort, it is partly reduced to the state of
sulphate with an excess of base : water takes away that part
which has not lost its acid.

100 parts of ibis sulphate gave 6i of carbonate of a clear
green.

The potashed sulphate loses 24-lOOdths of water. The re-
sidue acts like that of the sin]|)le sulphate. The potashed
sulphate only gives from 27 to 28 of carbonate for 100.

The two sulphates of nickel are transparent, of a fine eme-
rald green ; they are unalterable in the air. M. Proust
thinks that the sulphate of potash is united to that of the
nickel in a constant proportion.

Extraction of the Nickel on a large Scale, — Let there be
an ample solution of ore first calcined, and afterwards vi-
triolized with the residues of ether. It is requisite to sepa-
rate the nicke) from iron, copper, arsenic, bismuth, and
cobalt. The iron is at the 7naximum : in this state it has
Uttle affinity for the acids. We may then precipitate it to

the

of Colalt and Nickel. 345

!he state oF arsenlate, by means of potash, which we must
add gradually. Ammonia, or a prussiate^ afterwards proven
if all the iron has been precipitated.

Into the filtered solution we make a current of sulphuretted
hydrogen to pass j the copper, hismutli, and the whole of
the arsenic arc precipitated in the form of sulphurets.

When the sulphuretted hydrogen occasions no more pre-
cipitate, we reduce the liquor in order to crystallize it. The
potashed sulphate of nickel, less soluble than the potashed
sulphate of cobalt, is the first to crystallize. On repealing
the crystallizations, we succeed in separating the two salts;
as to the last portions of the salt of nickel, washing them
in cold water takes off the sulphate of cobalt they contain.

All these crystallizations require a bason of fine silver, if
we wish to proceed smoothly.

We ascertain that a salt of nickel is pure, when the preci-
pitate dissolved in ammonia abandons this solvent with-
out OUT finding any cobalt in it.

When we jM-ceipitate a sulphate of nickel, we must not
be too sparing of the potash : without this precaution we
might run the risk of precipitating sulphate with excess of
base ; which would alter the purity of the precipitate.

Carlonale of Nickel. — 100 parts heated in a retort give
from 54 to 65 of grccnislr gray oxide at the minimum.
When we heat it in contact with the air, the oxide i^
.black.

The minor oxide becomes carbona^te when exposed to
the air.

Hydrate of Nickel. — All the salts of nickel when thrown
into boiling potash are changed into green hydrate ; boiling
does not alter the shade of them. Potash neither dissolves
the hydrate nor the oxide of nickel.

The hydrate heated is reduced to gray oxide.

The oxide is in the state of hydrate in the saline com-
binations. The alkalis precipitate it in this state.

Major Oxide of NickeL — The carbonate and hydrate rise
jto the maTi'mum, when we put them in contact with the
x)xygenated muriatic acid. Jt is itiore difficuU to oxidize the
gray oxide.

The

346 On Coledl and Kkkel.

; The dry major oxide of nickel is black ; when in a mass
its fracture is vitreous.

This oxide, preserved in ammonia, gives out bubbles, re-
turns to the state of gray oxide, and is dissolved in the alkali.

It gives a considerable quantity of oxygenated acid, with
a muriatic acid at 15°. The solution is greenish yellow :
crystals are formed upon cooling.

The oxides of nickel are reduced like those of cobalt.
They are melted in the same way, with this difference only,
that the cobalt gives a larger globule.

This metal hns taken a surcharge of sulphur from 46 to
100 ; but the author has still his doubts on this subject.

Arsentie and Arseniate. — They are formed like those of
cobalt, and are of a fine apple-green colour. The arsenite
healed in the tube loses its colour with water, sets at liberty
some white oxide, and passes to the olive-green. Charcoal
is necessary in order to take away all the arsenic.

When heated in a platina spoon, the arsenic is speedily
dissipated. An oxide at the minimum remains.

The arseniate heated in a gun-barrel loses its colour with
water ; becoming of a hyacmth and transparent appearance:
but at a red heat it passes to the clear yellow, and remains
unalterable.

In the spoon the arseniate becomes white, reddens with-
out melting, or emitting the smallest arsenical fumes ; we
must avoid flame in order to decompose it.

Recapitulation.
M. Proust concludes from the foregoing facts, and from
those he has published in other memoirs, that cobalt, nickel,
and most of the other known melals, have only two degrees
of oxidation distinctly marked : he has not asserted, how-
ever, that a metal can only absorb two proportions of oxygen :
he only says that it is not yet time to admit all the oxides
hitherto spoken of, and in which we have neither seen the
quantity of oxygen ascertained, nor the combinations which
they are susceptible of forming with the acids ; and he adds
that colour is not a sufficient character by which to distin-
guish them.

8 There

The, mean Motions of the Sun and Moon, ^c. 347

There are only two metals which have as yet presented
to the author more than two oxidations : these are tin and
lead : notwithstanding this, the quantity of oxygen in the
ox'idi: of t'm {ihchastoi' aurumimisivum) is not yet known,
nor that oF the oxide in the nitrate of lead which has been
boiled with plates of this metal.

It seems that the different oxides of one and the same me-
tal may be intermediately dissolved, and form true combina-
tions. Thus the green oxide of cobalt is a combination of
blue and black oxide.

May not minium be a combination of brown oxide and
of oxide at 9 in 100, and analogous to the foregoing?

Finally; all the magnetic ores of iron and the attractable
sands arc mixtures or combinations of this order : if this were
not the case, what could prevent the minor oxide from rising
to the maximum P The oxide of the gun-barrel which has
served to decompose the water is also in the same case ; it is
formed of the two oxides.

LXIV. The mean Motions of the Sun and Moon, of the
Sun's Perigee, the Moon's Perigee and A^ode ; the Times
cfflieir several Revolutions, both in respect to the Equinox
and to the fixed Stars, and in respect to each other: de-
duced from the New Tables of the Sun and Moon lately
published by the French Board of Longitude. By James
Epps, Esq,

To Mr. Tilloch.

SIR,
C

*^HOULD you think the enclosed paper deserving a place ia
your Magazine, it is at your service. It contains the result
of very tedious though not difficult calculations; and, as it
exhibits^ an interesting view of the modern solar and lunar
astronomy, will, I think, prove acceptable to your astrono-
mical readers. 1 am, sir, yours &c.

James Epps.*

No. 4, Commercial Road,
May 14,1806.

The

3 JS Tke mean ^lotions cj the Sun and Moon,

The sun's mean motion in i a „• p -§ "I
respect to the equmox, in j^ - io Q ^ co
100 years^ or 36524 days - 99 11 29 46 36*73

,....,..,. in one year,
or 365 days - - - — 11 29 45 40'368W

The sun's mean diprnal
motion - - - - — -^ — .59 8*3297763

The motion of the sun's
perigee in respect to the
equinox, in 100 years, or
36524 days - - I 43 11'

, in one year,

or 365 days - - 61-8693188

The diurnal motion of the
perigee - - - -— — -^ — 0*16950498

Hence, the motion of the
sun's mean anomaly, in 100
years, or 36524 days - 99 1 1 28 3 25*75

in one year - — 1 1 29 44 38*499

The diurnal motion of
the sun's mean anomaly ^-^59 8*1602713

The moon's mean motion
in respect to the equinox, in
100 years, or 36524 days 1336 9 24 42 8-2

, in one year,

or 365 Jays - - - 13 4 9 23 4*8755

The moon's mean diurnal
motion - - - 13 10 35*0270561748

The motion of the moon's
perigee in respect to the
equinox, in 100 years, or
36524 days - - - 11 3 iff 5fl 44*4

in one year,

or 365 days - - - — j 10 39 45*79

The diurnal motion of the
perigee - - - ^ 41*05695979

Plence, the motion of the
moon's mean anomaly, in
100 years - - 1325 6 5 45 23*8

And

of the Sun*s Perigee , &fc* 349

And the motion of the

K » 5

moon s mean anomaly, m ^ c^ q i§

•f.i

to

one year, or 365 days - 13 2 28 43 19*085

The diurnal motion of the
mean anomaly - - 133 53'9700fll638

The retrograde mean mo-
tion of the moon's node, in
respect to the equinox, in
100 years, or 36524 days - 5 4 14 8 31*4

in one year,

or 365 days - - • 19 19 43*360557

The mean diurnal mo-
tion of the node - 3 10*63934344

The mean diurnal motion
of the moon from the sun 12 11 26*697280

The mean diurnal motion
of the moon from hernode 13 13 45*666400

From the above mean motions are deduced the following
revolutions :

The sun's mean revolution in ^ i; ^ 4

5^ >^ s «

respect to the equinox, called the ^ J ;^ b
mean astronomical, solar, or tro-
pical year - - - . 365 5 48 51*58732

The sun's mean revolution in
respect to the fixed stars, or the
mean sidereal year ; (supposing
the mean annual precession 50'* 1) 365 6 9 11*49648

The sun's mean revolution in
respect to the perigee, or the
mean anomalistic year - - 365 6 13 58*074

The entire revolution of the sun's perigee, in
respect to the equinox, is therefore 7645793
days, nearly, or 209 Gregorian centuries and
about 33 years.

Since the progressive mean motion of the
perigee in one year, in respect to the fixed
stars, is only U"*7693188, the sidereal revo-

iutlon

350 The mean^ Motion of the Sun and Moon, &Co

lution of the perigee will therefore be more
than five times that of the tropical.

The time required bv the sun <.• g "§ "I
in passing over one degree or ,§ :5 § cc
mean longitude - - - — 24 20 58*1433

The time required by the sun's
perigee, in performing the same,
is above 58 years, or more exactly 2123S 7 31 42*3205

The mean |>eriodical revolution
of the moon in respect to the
equinox 27 7 43 4-64670 •

The mean sidereal revolution of
the moon, or the revolution in re-
spect to the fixed stars - - 27 7 43 ll'477IO

The mean syiKxiic revolution,
or the revolution of the moon to
the sun, called a mean lunation Q9 19 44 2*850426

The mean anomalistic revolu-
tion of the moon - - - 27 13 18 33-3391155

The mean revolution of the
moon in respect to her node - 27 5 5 35*6053

The mean revolution of moon*s
perigee in respect to the equinox 3231 11 4 6*69936

The sidereal revolution of the .,

moon's perigee

The mean revolution of the
moon's node in respect to the
equinox - -

The sidereal revolution of the
node - - - ~ ."

Time of moon's describing 1""
mean motion - - - -

Time required by moon*s pe-
rigee in describing I'* motion

by moon*s anomaly -

by moon's node

Mean motion of sun's anomaly
during a synodic revolution, or one

lunation, 29^- 6' 19"-96ll066,

Mean

3232

13

36 41*26610

6798

4
H

14 51*1556

6793

2B 19'8rp3

—

1

49 17-17978

8

23

95 50-68531

—

1

50 13-0936

18

21

13 49*475

MiTieralogical Account of the Island of Corsica. 351

Mean motion of moon's ano- . .j | •«
maly for the same intervaf, « j| § c§
385^ 49' 0"- 8 186293.

Mean motion of the moon from
her node for the same interval,
390° 40' 13"-9587lCO.

Periodof 12 mean lunations - 354 12 48 34*205X

Period of 223 mean lunations,
for the restitution of eclipses - 6585 7 42 35*6450

LXV. Mineralogieul Account of the Island of Corsica ; con^
tained in a Letter from M, Ram passe, formerly an Officer^
in the Cars lean Light Infantry^ to M. Fa u J as de St»
Fond*.

1 SHALL novv endeavour to gratify your desire, commum-
cated to me on my leaving Paris, of having some detaik of
my mineralogical^ inquiries in Corsica, and particularly
upon the orbicular granite of that island, of wbich a single
isolated block only has yet been recognised.

In order to make myself master of the subject, it was ne-
cessary to visit the interior of the Pieve d*Orexza. and I first
proceeded to reconnoitre the high mountain called Santo-Pie-
tro-de-Rostino, from which proceed the enormous masses of
quartz mixed with green diallage, with which the bed of the
rivulet of the village of Stazzona is encumbered. I shall not
at present enter upon a detail of the reasons which should
incline us to reject the improper denomination of verdc
antico di arezza, which was at first given to this stone.
After this visit, I wished to direct my steps ta Liamoiie
by the Vleve de Caccia ; but the extremely warm temperature
which then reigned hindered me, and it was not until the
end of August following that I undertook this journey.

Before entering into the details of my excursion to Lia-
mone, allow me to mention a new rock which I disco-
vered in the Niolo : it is of a peculiar texture and composi-

♦ from Annalis du Museum tTHistoire XatureHe, tome vUi. p. 470.

tion>

352 Mifieralogical. Account of the Island of Cor sled,

tion, and I never met with it before. The following is the
route I took to the place where I found this beautiful rock.

By moving in the direction which I traced out to myself
when leaving Basiioj I not only followed some chains of
mountains from N.W. to S^and from E. to W. but I also tra-
versed several valleys, and turned considerable gulfs which se-
parate them in various directions. When I was in iho. Pieve
(TOstriconiy where the chain commences which divides the
island through its whole length to its southern extremity, I
traversed the highest mountains which presented themselves
to me, and among others that of Niolo, called in the language
to the country Monte- Per tusato, because it is pierced at its
summit. Its base seemed to be intersected by some de-
tached masses, and others adhering to it, of jaspers and por-
phyries of great variety. I followed the valley which leads
to the place called Santa- Maria-la- Stella. Between these
two points, south-east from the former and south from the
latter, and at an equal distance from both, there is a high
mountain covered with wood, upon the western brow of
which I discovered a block of stone, almost square, about
four feet and a half long. It was sunk into the ground, and
exhibited globular bodies on one of its side?, remarkable
from their disposition and colour, and fixed in the stony
mass : some were about an inch in diameter, whW^ others
•were larger or smaller : all of them presented^ a peculiar
character which I had never seen in any stone. Not more
than six inches of this rock was exhibited above ground; and
in order to ascertain its dimensions I took away the earth
which surrounded it. I then found that it was two feet and
some inches in thickness. I also observed that its angles
were entire and acute ; which made me think that it had
never been removed sipce placed there, and particularly be-
cause the part of the slope of the mountain where it was is
bare ; and because, among the various blocks and masses
which surround it, it is the only one which is covered with
vegetable earth. I could only bring away a piece weighing
about 24 pounds ; the rest was too large and heavy.

When the specimen was detached and exposed to view, it
seemed to me so beautiful and so extraordinary an appendage

to

Mlnerahgical Jccount of the Island of Corsica. 353

tx) the magnificent orbicular granite of Corsica, the celebrity
of which is so well known.

You may perhaps think I am exaggerating, but the fol-
lowing is the accurate description of the stone taken upon the
spot :

The rock, the heart of which seems to be porphyroiclal, has
its paste composed of stony elements of a petro- siliceous
nature, irregularly disposed in small grains, in points and in
lineaments more or less rounded off, tying as it were with
each other, and varying in colour in proportion to the va-
rious degrees of alteration the ferruginous principle, which
is very abundant in this rock, has undergone : nevertheless
its general aspect, when seen at a certain distance, is the
reddish brown mixed with white spots shaded with red.

It is in the midst of this paste that we observe regular
spheroidal bodies, from one to three inches in diameter,
scattered here and there at imequal distances, and imbedded
in the mass : the system of ibe formation of these kinds of
balls can only be considered as the result of a globulous cry-
stallization, which must have taken place rapidly; and not
like geodites, which would have been formed apart, and en-
veloped subsequently in a porphyritical substance.

The method of crystallization in question is so far remark-
able, that we can form no idea of it except by representing a
circle into which a multitude of small stony bodies, oblong
and compressed, of a petro- siliceous nature, very close to
each other, must have been directed in radii, and as it were
from end to end, from the circumference towards the centre
of the circle, which gives them the appearance of divergent
radii; and there has resulted from it a globulous solid,
which with the hammer we may drive out from the place it
occupies, leaving a hole of its own form behind it. The
tendency of the crystallization has been such, that we see
around the spherical bodies in question, in the paste of the
stone, and round the spheres, the matter of the paste itself,
which, according to the tendency it had to approach it, has
formed a kind of aureolus, or zones, which surround several
of the bowls, which may be more easily remarked than de»

Vol. 30. No. 120. May 1808. Z scribeds

3 54 Mineralogical Account of the Island of Corsica,

scribed : indeed, no precise or just idea can be formed without
seeing the stone itself.

The dimensions of my specimen are as follows : It is
1 7 inches broad, 1 2 high, and seven inches thick at its
base : the side which I have got cut and polished presents
l.*! or 16 of these globules, among which we may remark
several that are enchased as it were into each other.

After spending a considerable time on the spot where I
found this specimen, I proceeded towards Liamone on the
gulf of Valinco.

Having arrived at the village of Olmetto on this gulf, the
place pointed out to me as containing the orbicular granite,
I proceeded to Taravo. 1 dug np the makis covering a part
of the hillock on which Stazzona is situated, and minutely
examined every corner. I sounded the small lake in the
neighbourhood : I visited the sea- shore : I also sounded
the river, and explored it in various points by means of
divers : I even followed its course upon the two banks
for more than a league and a half: and finding nothing by
these means, I formed the resolution of exploring 45 miles
of ground beyond Stazzona.

I endeavoured to assure myself of the composition of the
eranites Iving upon the heights surrounding the great valley
of Taravo : T attacked every rock I saw, and found some
specimens the composition of which resembled the granite
in question.

After having pursued my researches still further, I entered
the bed of the Taravo, and traversed the two banks for
more than tvvo leagues : at the moment when I was re-
doubling my efforts to finish my investigation, I was
obliged to desist on account of the rain and snow, it being
now December.

I collected the various specimens of rocks which I pro-
cored at Valinco : and after having made a comparative ex-
amination of them w ith the orbicular granite, I ascertained
that in some of these specimens there were hornblend and
feldspar, but not in the same order, nor in the same arrange-
ment: nevertheless, I think we may inicr from these spcci-

mens:,

Mineralogical Account of the Island of Ctyrsica, 355

mens, that by finibhing the object of the visit I paid to the
two banks of the torrent, we shall perhaps succeed in dis-
covering the primordial masses of the beautiful orbicular
granite of which a small partial mass only has been hitherto
dicovered : ih^ angles of it were rounded, and it was found
isolated upon the beach of Taravo, half a league from the sea,
in the gulf of Valinco.

"From the information I procured on this occasion, I
think I proved to a certainty that the small mass of this gra-
nite, already known, comes from no place except Corsica ;
for you know that several naturalists have formed various
conjectures upon the subject.

In the course of this tedious journey, I had also an op-
portunity of discovering an ore of iron, the stratum of
which is half a league in length.

After having passed "the river Oposata, in order to arrive
at Calvy, in a plain above the village of Calenzana, to the
eastward of Galeria, I found a stratum of iron ore, placed
horizontally in a yellow earth, which at times disappears
throughout the whole length of the ore, and the mineral of
which is presented in three diflerent views. At first it ap-
pears under the character of scaly iron, arranged in thin
layers, mixed with a yellowish ochrey earth ; afterwards it
appears as a heavy blackish iron, compact, and almost en-
tirely disengaged from every heterogeneous substance ; and
under a third aspect, in elongated spheroids from four to
five inches in diameter, exfoliating at its surface, and com-
pressed at the two sides : this gives it angles at intervals ; and
the sandy character and composition of it made me deno-
minate it arenaceous iron : and I procured the necessary
specimens for the experiments I intended to try upon it.

Having ascertained from these trials that this ore Was very
productive, I transmitted to the council of mines several
specimens of the above stratum, begging them to publish the
result of their assays.

Z 2 LXVI. On

[ 356 ]

LXVr. On the Identity of Silex and Oxygen, By
Mr, Hume, of Long' Acre ^ London,

A

[Continued from p. 280.]

To Mr, Tilloch,

SIR,

MONG these promiscuous observations, it would be un-
pardonable to omit iron, which is one of the more constant
associates of silex. These two ingredients seem to be al-
most inseparable companions, especially in every thing of a
primeval nature ; for, in all original districts, mountains,
rocks, and soils, and in every native compound of any con-
sequence and extent, whatever the aspect, situation and
contents may be, these two elementary bodies are sure to
present themselves, and, T may add, are always united ;
for, though the silex maybe elicited from the mineral in its
simple form, the metal, on the contrary, is always oxidized.
So universally is this metal dispersed through the works
of nature, that very few instances occur in which it is to-
tally absent ; its ubiquity is truly proverbial, and is exceeded
by nothing, if we except silex or oxygen ; indeed it pervades
almost every solid substance, and even animal and vegetable
bodies are seldom exempt from its influence, but often exhibit
iron evidently as a constituent in their s^j'stem. Hence, the
history of iron becomes a most interesting subject to the
physiologist, and, if we add its wonderful property of mag-
netism, it seems to be one of the most fertile for the ima-
gination of every philosopher. As this metal is never dis-
covered in the pure state, but is more frequently conjoined
with oxygen than any other body; and as this process seems
to have been effected in the immediate vicinity of silex, I
see no particular or unreasonable objection, if, in all such
instances, we assign the genuine cause of the oxidizement
of iron, solely to this prototype of oxygen. I feel less diffi-
culty in admitting this conclusion, when it is consi-
dered, that the more cogept examples are dcducible from
originally Jormed matter, from the real primordial rock,
coeval \vith the globe itself, and made tangible, probably,

soon

On the Identity of Silex and Oxygen, 357

soon after, or even at that very period when, the ^^ Earth
was without form and void.**

The inlimacy between silex and iron, and the consecutive
oxidizement of the latter, need not be further urged ; it oc-
curs in such numberless cases, that whoever is at ail conver-
sant in mineralogy, and will take the trouble to search with
candour, can be at no loss for evidence, sufficient to establish
this singular concomitance. Thus, let us take, as an instance,
that substance, familiarly known by the name of emery.
Here, the iron is truly united to the silex in a very close man-
ner, and not as a mere mixture, for the metal is oxidized and
imbedded in this surplus of oxygen. "This,** says M.Haiiy,
speaking of emery, " is a true combination of quartz and
iron, in which the two substances contract a stronger ad-
herence than a mere interposition of their molecules.*'

Though iron is considered ^s a pure metal and a simple
substance, that is, when divested, by the usual methods, of
the common impurities, to which it has a habitual affinity,
particularly of these, viz. carbon, phosphorus, and silex; still,
there is strong reason to believe that it has never been totally
exempt from one or other of these substances. Indeed, it ap-
pears that some of these very impurities are required to render
the metal more perfect, to add to its splendour, ductility,
and other properties, which the arts demand. Thus, to make
good steel there must be an addition of carbon as well as
silex ; and, if brilliancy, hardness, and a susceptibility of
higher polish are to be considered as improvements, the
carbon and the silex, in this case, seem to render the metal
still more metallic, if such a term may be allowed.

In an analysis of four different specimens of steel, by
M. Vauquelin, the result was this, taking it on an average
to avoid fractions : that one hundred thousand parts of these
samples of metal consist of 9817 of iron, 723 of carbon,
870 of phosphorus, and rather more than 288 of silex. That
it is very difficult to deprive iron of all foreign matters, may
be readily conjectured from this philosopher's labours, and
the following observation confirms this truth, that iron is
never pure. " The analysis of the varieties of steel,** says
this very accurate chemist, *^ is one of those parts of the.

Z 3 science

35 S On the Identity of Silex and Oxygen,

science the least advanced and the most difficult, especially
when our object of research is the exact estimation of the
principles which they contain : — it is thus, for example, that,
in dissolving steel in dilute sulphuric acid, the hydrogen
which is evolved, dissolves and carries off a part of the
carbon, the quantity of which varies according to a multi-
tude of circumstances."

From this and other authorities, and from a prejudice,
which, I acknowledge, 1 have long been disposed to che-
rish, it may be inferred, that whatever emits smell cannot
be considered as a simple body, and hence, the purity of
hydrogen as an clement must be doubted ; that species,
however, which we obtain from the decomposition of water
by the metals, is certainly very objectionable, if there be
any truth in this observation ; for the gas is never free from
a ver^ perceptible odour, whether it has been procured by
means of zinc or iron.

It is certainly not always prudent to generalize too freely
upon these subjects, yet it is difficult on some occasions to
avoid it entirely. The hydrogen gas, alluded to by M. Vau-
quelin, in these analyses, was undoubtedly impure, as
it contained a certain portion of carbon from the metal,
though not the whole ; for, finding this mode of operating
inconclusive, he at last had recourse to the sulphurous acid,
with which he apparently succeeded in separating the whole.

Fluoric acid, from its peculiar effects upon the siliceous
compounds, deserves a particular notice in the present in-
quiry, especially as its whole history remains still clouded
with inconsistency and ambiguity] for, either the tables of
affinity respecting its habitudes are erroneous, or the acid
itself must be considered as a monstrous anomaly in the
doctrine of chemical attractions. These tables begin with
lime, and go on progressively with some of the earths and
alkalies to silex, the very last in the enumeration, with
which, by the way, it has never yet been united so as to
produce a true salt. From Bergman's experiment, we learn,
that he dissolved silex in fluoric acid, and that after the so-
lution had remained undisturbed for two years, a number
of crystals had formed at the bottom of the liquor in the

• • vessel.

On the Identity of S ilex and Oxygen. 359

vessel. But, what were these crystals? They were pure silex,
aod had deserted this very acid, which, in all other cases,
would have seized on it and dragged it into even aeriform
existence. The native fluate of lime is so very generally con-
taminated with silex, if this expression may be allowed,
that it is probable no fluoric acid exists without some of this
ingredient; it may indeed owe its origin to this body, so
uniformly are they associated.

But, that singular influence of fluoric ^cid upon silex,
the corrosion of glass, is what has been chiefly noticed by
most authors, for it does not appear that a direct application
to the mere silex has yet been attempted, at least, with thai
precision which might have obtained a satisfactory result.
T-hat this acid should prefer the silex to the alkali, and in
a case of single elective attraction too, is contrary to every
table that has yet been published, and hence, in this ex-
ample at least, it forms an exception to the general rule.
But if, in similar experiments, the acid selects the silex from
lime, a substance which is placed at the top of the list, in all
arrangements, how much further does this error extend?
Though in making experiments with this very curious li-
quid I have employed various species of glass, ^principally
with a view to improve this method of etching, I have
generally preferred plate- glass, on account of its form, con-
venience, and greater capability to endure the necessary
pressure, so as to secure a number of perfect impressions.
This glass is always, without exception, composed of
lime, silex, alkali, and, occasionally, some other ingredients
of less consequence in the present question.

It is astonishing, that in all the accounts of the decom-
position of glass by fluoric acid, and even by other means
of still greater energy, by electricity, little notice has been
taken of the oxide of lead, and the subseqient disposition
of the whole of the ingredients. I make no doubt, that
flint-glass has been more frequently employed than any
other, but I do not find that silex has ever put on that pe-
culiar character of an earth, an alkali, or a salifiable base,
ajid attached itself to the negative pole. On this subject, I
confess, I feel extremely solicitous, as, in the late very

Z 4 splendid

300 On the Idejitity of Silex and Oxygen^

splendid discoveries, which now, and probably will ever
continue to, engross the attention of the scientific world,
the decomposition of glass and consequent disposal of all
its ingredients, form a question, to nie al least, of the ut'*
most interest; since, as far as I can judge of the pheno*
mena, which have already been described, there appear cir*
cumsiances more likely to confirm, than invalidate, my
opinion of the nature of silex.

There is a remarkable similitude in the effects of oxygen
and silex on the metals, particularly in that process called
vitrifcatio??, which is, in every meaning of the word, a
coniplete saturation. By means, of these, particularly the
silex, all the metals, perhaps, with no exception, from
being the most opaque bodies in the universe, may be ren<»
dered quite pellucid, affording an endless variety of the most
charming tints, as useful as they arc elegant, smce it is chief-
ly from metals and metallic. substances that the most durable
and valuable colours arc obtained for staining glass and mak-
ing artificial gems. The best op.ike colours, such as are most
suitable for enamel, water, oil, crayon, and all other descrip-
tions of painting, are derived also from the metals, combined
with one or both of these substances ; and though alumine
and other bodies are occasionally present, they are as ofter^
absent. Even the precious stones and the less valuable peb-
bles, spars, and an infinite list of fossil productions, seem
to derive their intrinsic value, beauty and other excellen-
cies, entirely from the power of silex on the metals. Thus,
the dull opacity of lead is as effectually changed by the sand,
used in the composition of flint-glass, and the whole com-
pound appears not less diaphanous, than the very same metal
is, when, by means oi oxygen ^ it is dissolved in nitric acid,
properly diluted with water ; such, however, is the infe-
rence I would draw from these premises.

The near connection between potash and silex, is not less
manifest than in the other associations which have been
already noticed ; indeed, seeing with what avidity the base
of potash (according to the late discoveries) clings to oxy-
gen, I am furnished with this plea, that its original and
necessary quantity had been obtained from silex ; for all the

potash

On the Tdenlity of Silex and Oxygen. 3^1

potash ^of commerce contains silex, and retains it with some
di'gree oF force, not as an adventitious ingredient, but ra-
ther as the superabundance oi' that primitive store, from
whence it had derived that portion which is essential to its
existence as potash. Now, that the constitution of potash
no longer remains in doubt, and that oxygen has been proved
to be as essential to the formation of potash as it is to that of
sulphuric acid, I see no explanation more congenial and satis-,-
factory than what I have here ventured to suggest, especially
uhcn it is proved that the primitive seat of potash is in rocks
^nd stoneSy and in the very centre of such bodies, where the
^itmosphere can have had no influence ; for, as far as regards
its vegetable and animal existence, all is merely secondary,
and, consequently, does nut apply so forcibly in this theory,
though, even here also, we need be at no loss for proofs.

The power which silex exercises over potash, soda, and.
^ variety of other substances which enter into the compo-
sition of glass, is a notorious instance of its neutralizing
efficacy ; for no acid more completely obtunds the acrimgny
of alkaline bodies and disarms them of their corrosive clija-
racter. The effervescence, which resvills when silex and
the alkali enter into fusion, and form this insipid compound,
is not observable till the materials are on the point of per-
fect conibinalion : hence, as son)ething is apparently evolved,
neither oxvgen nor any other aeriform fluid can be supposed
to enter ; so that the acidity, if the term may be applied, to
coerce the alkaline matter, is alone due to the sand which
is usually employed in the making of this beautiful and use-
ful compound. Indeed, vitrification, in all instances, seems
to be accon)plished by silex or by oxygen ; and the glass
of lead, of antimony, of phosphorus, borax, or of any other
body, is due to one, as much as the glass in common use,
is to the other of these oxygenating agents.

In many very trite and familiar experiments, upon bodies
containing either silex, an acid, or oxygen in some con-
dition or other, tfee phenomena which succeed may be
traced to the same cause. Thus, scintillation of hard bodies
on collision again'st each other, as flint against seel ; that of
two siliceous stones, which emit not only light but the pe-
culiar

362 On the Identity of Silex and Oxygen.

culiar quartzy or rather sulphurous smell, already noticed ;
the effects produced by various species of phosphor! ; fric-
tion of two pieces of borax ; the electric nature of glass ;
that of amber, tourmaline, and of resinous bodies ; the
light evolved by friction and collision of bonnet-cane and
other vegetables which contain silex ; and, in short, all other •
analogous examples may be adduced as additional illustra- "
lions on this subject.

If I were to select a case, in which silex seems to be de-
posited as it were, and deprived of the caloric which had
suspended it in the state of gaseous oxygen, it would be ^
that of a natural hot-spring, such as the Bath-waters, which •
are confessedly impregnated with sand or silex, not merely •
in suspension as an accidental material, but perfectly dis--'
solved so as to be imperceptible to our sight. Besides these ^
waters, all other hot springs contain silex In solution ; that
of Carlsbad; the Geyser, and Rykum, in Iceland; and many
others, which, it is said, issue, for the most part, from
granitic and other siliceous rocks. If these waters were cold
the argument might fail, but while the temperature of the
ambient medium can be taken into the account, I should
not be willing to retract this opinion, as far as it concerns
the nature of all hot-springs. It is f;tated from good autho-
rity, that in the kingdom of Portugal alone, there are up-
wards of 200 of these springs, the greater number of which,
and the hottest, originate where silex is most abundant.

The presence of nitrogen in the Bath- waters, and, pro-
bably, in all other hot-springs, is a curious occurrence, and
furnishes a proper theme for speculation. Whether it be
the remainder of decomposed atmospheric air, which has
been bereft of its oxygen, and that this is disposed of
in the water, in the way I have supposed, is a question
I shall not urge. The late Doctor Black analysed the hot-'
springs of Iceland, but the analysis, I believe, was not
performed upon the spot, and, consequently, no notice
could be taken of nitrogen gas. In the gallon of Geyser
water, he found upwards of 31 grains of silex ; and in the
other, that of the Kykura spring, the proportion was 29
grains of the same ingredient in the English gallon.

The

Dissection of a Case of Hydrocephalus intermis, 363

The effect of silex in various cases is the same as an acid,
and in some situations, where an acid or acid properties
really exist, no other cause is present. All acids we know
are not sour, some on the contrary, are insipid, and, there-
forcy it would he too much to expect silex to possess this
property. It is, however, a strong support to this question
to see my idea of its general acid quality corroborateilr by
others, for it has lately been observed, (Journal des Mines,
tome XX. p. 245.) that " in the analysis of ores, silex acts
very sensiidy as an acid.'*

[To be continued.]

LXVII. Report of Surgical Cases in the City and Finshury
Dispensaries, for November 1807; containing a Dissec-
tion of' a Case of Hydrocephalus internus. By John
Taunton, Esq,

In the month of November there were admitted on the
books of the City and Finshury Dispensaries 237 surgical
patients.

Cured or relieved — 229

Died — — 3

Under cure — 25

257

Since which time there have been admitted 1007. -

Some time since I was requested to examine by dissec-^
tion, the head of J. W. aetat. about 9 years. It was remarked
at the birth of this child, by a very intelligent surgeon, that
the head was large, and that it was probable there was water
contained in the brain. The child grew, and enjoyed good
health till the 1 7th month after birth ; but the head continued
large. He was then seized with the hooping-cough, which was
very violent, and he lost his sight for some time. It was now
pronounced decidedly, to be a case of hydrocephalus internus.
On his recovering from the hooping-cough he regained
his sight and strength, so as to enable him to walk with tlie
hand of his nurse, or in a^ go-cart : his appetite was goody

and

364 Dissection of a Case of Hydrocephalus intemus.

and his evacuations regular : but his head increased in size
beyond the proportion it ought to have borne to the other
parts of the body. He was naturally of a lively turn, and
reasoned with great acuteness for his years, — observing, that
it would be very difficult to regain his present lime, which
-was lost, in point of education.

About two years before his death he wore a quicksilver
girdle, and took some very stimulating snufF, from which he
appeared to be relieved for some time.

About six months preceding death, he fell, and struck the
back part of his head; from which he complained of great
pain, which brought on violent vomiting, fits, and sometimes
a loss of all sensation; as in a kind of lethargv.

About ten weeks before death, a blister was applied be-
tween the shoulders, from which he appeared to receive
consicjerable relief; the head was shaved, and some stimulat-
ing oils rubbed in, as ol. origan, 8cc. : after one of these
rubbings he lost his speech entirely, and remained insensible
till his death.

The child was of a spare habit of body ; but independent of
the head, which was greatly enlarged, had a healthy appear-
ance, and was moderately tall.

The bones of the scull were unusually thin, to which the
dura mater did not adhere with the common degree of
firmness; the vessels were turgid ; otherwise the membrane
and its sinuses were natural.

On raising the dura niater, the brain presented an uni-
form smooth surface, without the least convoluted appear-
ance; the tunica arachnoidea and pia mater were healthy,,
the vessels lying upon the surface of the latter membrane.

The cerebrum was flaccid, and the undulation of the water
could be distinctly perceived : on removing the upper part of
the right hemisphere, although the incision was made more
than two inches above the corpus callosum, it ppened ihq
lateral ventricle: tne two lamiuje forming the septum luci-
dum were separated from each other more than half an
inch.

The lateral ventricles were greatly enlarged, and contained
thirty-two ounces of a siraw-colourcd fluid; but theve w^s

not

Notices respecting New Books, 365

not any appearance of inflammation on the membranes lining
these cavities.

On exposing the cerebellmn, the right lobe appeared
somewhat flaccid, in which a cist was placed containing
eight ounces of a brown straw-coloured fluid, not having any
communication with the fourth ventricle or other outlet.

The optic nerves were small, soft, and of a brown colour.

The other parts of the brain and nerves were natural.
We perceive that the reasoning faculty was more complete
than could have been expected. From such extensive de-
rangement of parts, is it not probable that the early and slow-
formation of the fluid, and consequent distension of the
lateral ventricles before the bones of the scull were com*
pletely ossified. Or capable of affording that resistance which
they are in the adult state, prevented in a great degree the
effects of pressure, by allowing the bones to enlarge from
the gradual pressure from within daring their more membra-
nous state ? as we see a comparatively trifling pressure on the
brain in the adult, when the bones are iucapable of exten-
sion, whether it be in consequence of external violence or
of inflammation, by which a fluid is effused into the lateral
ventricles, productive in a short time of the most serious
consequences.

We also perceive that nearly one half of the substance of the
cereLelhim was destroyed, by its place being occupied by a
cist which contained eight ounces of a fluid; and yet the ca-
pability of associating ideas remained, which was also observed
in the case of miss M. See Phil. Mag. vol. xxix. page 169.

Greville street, Hatton Garden, JOHN TaUNTON".

Mav 24, 1808.

LXVIII. Notices respecting Netv Books,

i\j.R. Parkes has for some time been engaged in revising
and correcting the Chemical Catechism, in order toaccom-
tnodate every part of that work to the new discoveries of
Davy and others. A new edition thus amended, and with
other very considerable additions, is in the press, and will
be-ipfiady for delivery some time in June.

Mr,

366 Royal Society,

Mr. Carnuchael proposes to publish in the course of the
ensuing summer, the second edition of his Essay upon the
^Effects of the Salts of Iron upon Cancer, with many addi-
tional cases, and several interesting practical observations
upon that disease.

' Mr. Carmichael has received some communications from
practitioners, concerning their experience of those prepara-
tions, for which he begs to return his warmest thanks; and
he at the same time takes this opportunity of earnestly re-
questing such of the profession as have deemed the remedy
he recommended worthy of a trial, to inform him (addressed
to No. 3, Gardener's Place, Dublin,) of their experience of
its effects, before the end of June next, in order that he
may insert their observations in his Essay, and that thus the
merits of the remedy may be justly appreciated.

LXIX. Froceedings of Learned Societies,

ROYAL 50CIETV.

April 28. — This society met after the Easter recess, the
president in the chair. A mathematical paper, by Doctor
Young, was read, on the motion of fluids in flexible tubes,
and the resistance of angular tubes to such fluids. A num-
ber of hydraulic experiments were performed ; but the re-
sult was not of a nature to be stated here. This paper was
merely designed as prefatory and introductory to this author's
next Croonian lecture on muscular motion.

May 5. — A letter from Mr. Cadell, at Paris, to H. Davy,
Esq., secretary of the Royal Society, was read. In this letter
Mr. Cadell states, that the French chemists have success-
fully repeated Mr. Davy's experiments upon the decompo-
sition of the fixed alkalies ; and that they have found a re-
markable confirmation of his discovery in the action of
heated iron upon potash and soda.

This chemical result has been obtained by Messrs. Gay
Lussac and Thenard. These gentlemen introduced potash
into the\)ottom of a gun-barrel bent in the form of an S :
iron filings filled the middle of it, which was strongly heated.

By

Royal Society, 3G7

By the action of the potash upon the healed, iron, it is de-
composed, and the metallic base partly distils over, and is
partly found in a state of alloy with the iron. — ^The same
letter states, that Mr. Berthollet jun. has read a paper to
the Institute, in which he endeavours to confirm his father's
analysis of ammonia.

May 12 and 19. — ^The president in the chair. These two
evenings were occupied in reading an interesting and able
paper containing the results of an analysis of numerous spe-
cimens of different calculi, by Mr. Brande. The object of
the inquiry was to ascertain the relative quantities of uric
acid, and phosphats of magwesia and lime ; and to determine
the effects of the usual solvents, alkali and acids, for calculi
in the bladder and kidneys. It appeared that out of 150
stones, 60 were found composed of phosphoric acid and ani-
mal matter, and that only 12 were found of pure uric acid ;
the phosphats of magnesia and of lime, with a slight por-
tion of uric acid and animal matter, were the most common.
Some of the stones had pieces of bougies, hazel-nuts, and
peas for nuclei. To Mr. Brande's experiments Mr. Home
added some practical observations, tending to prove that, if
alkaline solvents were used, they might dissolve the uric
acid ; but that ihe phosphoric, which is always the most
plentiful, would thereby be increased, and the virulence of
the disease, however mitigated for the moment, would
eventually become much more dangerous. The same ad-
verse effects were ascribed to the use of acids as solvents : so
that we have yet to discover a safe and efficient remedy for
calculous diseases.

May 26. — The president in the chair. The reading of a
paper, by Messrs. Allen and Pepys, on the effects of respira.
tion on the atmosphe're commenced. The authors took a ge-
neral view of what the principal philosophers have written on
this subject, as an introduction to their observations ; and
expressed a hope of ascertaining with more accuracy than
preceding experimenters, by means of their eudiometer, the
quantity of oxygen consumed, and carbonic gas emittcd,^
by the lungs in ^ given period.

UNIVERSITY

368 University of Ed'mlurgh. — JVernerian Society,

UNIVERSITY OF EDINBURGH.

We congratulate the lovers of science, as well as the pub-
lic in general, on the Sj>lendid acquisition which this Uni-
versity has just now made by the magnificent collection of
minerals bequeathed by the late Dr. Thomson of Naples.

This celebrated mineralogist, during a long residence in a
country extremely fertile in the most interesting products of
the mineral kingdom, has lost no opportunity of forming a
most splendid collection, which, having lortunately escaped
every danger, has arrived in Edinburgh untouched. Go
vernment not only indulgently remitted the duties> but
allowed the whole to pass unsearched.

The liberal endowment (with which Dr. Thomson has ac-
companied this l^equest) of 1500'., the interest of which
he has destined for the payment of a lecturer on mineralogy,
and the support of the cabinet, we hope, will be the means
of handing it do-wn to posterity in its present high state of
preservation. — It is contained in forty very large boxes,
•which are deposited in the museum of the University ; and,
we understand, proper cases are making for the reception of
the specimens.

The interesting and valuable collection of the late inge-
nious Dr. Hutton, of this place, has also been deposited in
the museum.

WERNERIAN NATURAL HISTORY SOCIETY.

At the last meeting of the Wernerian Natural History
Society (14th May), Mr. P. Walker read an account of the
Birds that frequent the neighbourhood of Edinburgh. He
enumerated 178 species; of which 11 belonged to the. genus
Faleo ; 4 to the genus Strix; 1 to Lanius ; 8 to Corvus ;
1 toOriolus; 1 to Cuculus ; 1 Picus ; 1 Alcedo; J Upupa ;
I Certhia ; 2Sturnus; 6 Turdtis; 1 Ampelis ; 2 Loxia ;
CEmberhiza; 8 Fringilla ; 1 Muscicapa; 3 Alauda; 15Mo-
tacilla ; 4 Parus ; 4 Hirundo ; 1 Caprimulgus; sCoIumba;
1 Phasianus; 6 Tetrao; 3 Ardea; 6 Scolopax ; 7 Tringa ;
4 Charadrius ; I Hasmatopus ; 3 Rallus ; 3 Fulica; 4 Po-
^iiQcps ; 4Alca; 6 Colymbus : 2 Sterna 5 12 Lai us: 1 Pro-
3 cellaria;

JVer^erian Natural History Society, 369

cdkria ; 5 Merganser; 20 Anas; 4 Pelecanus. This account
Was accompanied wiih interesting observations on the di-
stinctions of several of the species, their changes of plumage
at different ages and times of the year, and their kind of
food 5 and specimens of some of the dubious species were
exhibited.

Mr. Jameson, at the same meeting, read the following
mineralogical queries, and stated the reasons that induced
him to consider the objects pointed out by them as deserving
the particular attention of mineralogists.

Mineralogical Queries,

I, In what species of rock are the metalliferous veins of
tyndrum situated, and what are the minerals they contain ?

9. Are the leadglance veins of strontian situated in sienite,
and what are their other geognostic relations ?

3. Are the trap-veins that traverse the mining field at
Strontian, basalt, porphyry-slate, or green-stone ; or do ail
these different species of rock occur in that district?

4. Does the quartz rock of Scuraben and Morven in
Caithness, and of Portsoy in Banffshire, occur in an uncon-
formable and overlying position, or does it belong to the
conformable primitive rocks, as clay-slate or mica-slate?

5. Does not the granular rock of Ben Nevis rather be-
long to the sienite than the granite formation?

6. Does the rock of the Hill of Kinnoul near Perth be-
long to the floetz-trap of newest floetz-trap formation ?

7. Is the mountain of Cairnsmuir in Galloway composed
of old granite ?

8. What are the extent and particular geognostic relations
of the black pitchstnne of Eskdale-muir in Dumfries-shre ?

9. Does the black pitchstone of the Cheviot Hills belong
to the newest flcetz-trap formation ?

JO. On what formation does the porphyry-slate of Braed
Hills near Edinburgh rest, and what are the venigcnous aud
imbedded fossils it contains ?

II. What are the geognostic characters and relations of
the edge and flat coal bed? or seams in Mid-Lothian ?

Vol. 30. No. 120» May 1808. A a if. Oa

370 London Royal College of Surgeo?is. — M, Carnot,

12. On what formation does the CaUon Hill near Edin-
burgh rest ?

13. Does the greenstone of Corstorphin Hill belong to the
independent coal formation?

14. Does the hill on which the town of Stirling is built
belong to the coal formation ?

15. What are the geognostic characters and relations of
the veins that traverse or are included in the greenstone of
the independent coal formation ?

16. What are the characters of the transition greenstone
of the south of Scotland ?

17. What are the particular species of petrifactions that
occur in the transition limestone near the Crook, on the
road from Edinburgh to Moffat ? P. N. Sec.

ROYAL COLLEGE OF SURGEONS, LONDON.

The Royal College of Surgeons have adjudged the Jack-
507/za/z prize for the best dissertation on '^Diseases of the
Eye and its Appendages, and the Treatment of them,'' to
John Hvslop, Esq. Surgeon, Fenchurch-street. The same
gentleman obtained the prize in 1 805, for the best disser-
tation on " Injuries of the Head."

LXX. Intelligence and Miscellaneous Articles,

M. CARNOT.

W iTH our present number we have given a head of the
above celebrated French author, whose ^cellent Treatises
on the Infinitesimal Calculus, and on Machines, have ap-
peared in this work. Of a character so well known among
men of science, it is unnecessary that we should say more
than merely that he has been successively a member of the
first Legislative Assembly, the National Convention, the
Directory, and the National Institute of France. In 1800
he was the French minister of war. Besides the works al-
ready enumerated, M. Carnot is the author of an Eulogium
en Marshal Vauban, a discourse which gained the prize of the

Dijon

Cotton. — Travels. — Pyrosoma Atlanticum, 371

Dijon ac ad einy in 1784; a Collection of Fugitive Poetry;
and of several Reports to the Convention, and Speeches made
while President of the Directory ; all of which have been
j)rinted and extensively circulated. M. Carnot was born
the 13th of May, 1733.

COTTON.

M. Louis Dupoy, a colonist of St. Domingo, lately ar-
rived in France with a variety of seeds and specimens of
the cotton plant. The seeds have been distributed among the
members of the agricultural society of Paris; and at a late
meeting, several reports were read from members who had
attempted the cultivation of this commodity in France : all
these reports concur in giving a most flattering account of '
the success of the experiment. In Provence and Languedoc
in particular, the crop of cotton was very abundant, and
equalled in quality the production of the West Indies, as has
been certified to the Frfnch legislature by several colonists.

TRAVELS.

M. Michaux, the author of Travels through North Ame-
rica, has been recently sent by the French government, a
second time, to explore the forests of that vast continent.
He is now actively engaged in fulfilling the object of his
mission, and has transmitted to the professors of natural
history in the French Institute, several specimens of seeds,
with a view to the cultivation in France of the American
oak and other useful trees.

PYROSOMA ATLANTICUM.

M. Peron, in his late voyage, observed this animal, not
described before by naturalists, in between the 3d and 4th
degrees of N. latitude. Its luminous property renders it
one of the most splendid of all known zoophites. The
darkness was intense when it was first discovered, the wind
blew with violence, and the progress of the vessel was rapid.
All at once there appeared, at some distance, a vast sheet
of phosphorus floating upon the waves before the vessel. The
ship having passed through this brilliant part, the crew disco-
vered that the light was occasioned by an immense number

A a 2 of

372 Chinese 'Radish. -^Lectures.

of small animals, which swam at difierent depths, and af3-
. Sumed various forms. Those which were deepest looked
like red-hot shot, and those on the surface resembled tubes
of red-hot iron. Some were soon caught, and they were
found to vary in size from three to seven inches. All the
exterior surface was bristled with thick oblong tubercles,
shining like so many diamonds, and these seemed to be the
principal seat of phosphorescence. In the inside there ap-
peared a multitude of oblong narrow glands, which pos-
sessed the phosphoric property in a high degree. The co-
lour, when at rest, is an opal yellow mixed with greeny but
on the slightest motion, or spontaneous contraction, the
animal instantly becomes luminous. As it loses its phos-
phorescence it passes successively through a number of tints,
^uch as red, orange, green, and azure blue.

CHINESE RADTSW.

Experiments lately made at Venice show that the oil of
the Chinese radish is preferable to any other kind known,
not only for culinary purposes, and giving light, but also
is a medicine. From the experiments lately madti by Dr,
Oliviero, it is found to be extremely usefyl in rheumatic and
pulmonary affections, and has been employed with much
success in convulsive coughs. It is not liable to spoil by
keeping, like other oils, nor is the plant injured by the
strongest frosts. The^ seed, which is very abundant, is
gathered in May and June,

LECTURES.

Dr. Satterby and Dr. Young propose to gire two Courses
of Medical Lectures next winter at the Middlesex Hospital,
Dr. Satterby's will be Clinical Lectures, and any of the
pupils of the hospital attending them will have the privilege
of seeing the patients whose cases are discussed. He will be
assisted in the department of morbid anatomy by Mr. Cart-
Wriorht. Dr. Young's Course will be on the Elements of
the Medical Sciences in general, and on the Practice of
Physic in particular. It has been erroneously stated in se-
VSriil periodical publications, that Dr. Young had a large

medical

Lectures.— Patents for New Inventions, sfS

iwpdical work nearly ready for the press : the mistake arose
from his having been for some time engaged in the prepa-
ration of these Lectures.

Mr. George Singer is now constructing a powerful Vol-
taic Battery; to be employed in a Course of public Lectures
ou the Chemical Agencies of Electricity. These .Lectures
will comprise the Exhibition of all the recent Discoveries ;
and are arranged for delivery early in the month of June, at
the Scientific Institution, No. 3. Prince's-slreet, Cavendish-
square.

Dr. George Pearson, F.R.S., and Senior Physician to
St. George's Hospital, will recommence his Summer Course
of Lectures on Physic and Chemistry, on Monday June 6,
at No. 9, George- street, Hanover- square, at the usual
Morning Hours j viz. the Therapeutics at a quarter before
Eight: the Practice of Physic at half after Eight ; and the
Chemistry at a quarter after Nine. — Clinical Lc<:tures are
given, as usual, on the Patients of St. George's Hospital
every Saturday morning, at Nine o'clock ; and the Prac-
tice of Vaccination \\\\\ be taught at the Institution in
Broad-street, Golden-square, during the Summer Course.

j;iST OF PATENTS FOR NEW INVENTIONS.

To Eichard Willcox,of the parish of St. Marv, Lambeth,
mechanist; for certain niachinery, whereby all objects in
the sea or clear water can be discovered from the surface
thereof with accuracy; and for raising, suspending, and
towing into harbour ships of war, and every other descrip-
tion of vessels that are or may be sunk at sea or near the sea-
coast, channels, harbours, road -steads, or other places, and
removing sunken rocks or other obstructions in rivers, har-
bours, and channels. March 3, 180S.

To John Cowden and John Partridge, of Francis- street,
Tottenham Court Koad, stove-grate manufacturers; forcer-
tain improvements in register and other stoves. March 3.

To Thomas Jeflerson, of the parish of St. Saviour, Souih-
wark, tanner and leather-dresser; Joseph Ellis, of the same
parish, tanner and leather-dresser; and Alexander Galloway,
ofHolborn in the county of Middlesex, mechanist and engi-

A a 3 neer ;

374 List of Patents for New Inventions »

neer; for a machine for the purpose of finishing, glazing,
and glossing of leather. March 7.

To Marc Isanibard Brunei, of Chelsea ; for certain im-
provements on circular saws for sawing wood in an easy and
expeditious manner. March 14.

To Henry Maudslay, of Margaret-street, Gavendish-
squ^re, mechanist ; for a machine for printing calicoes and
other articles. March 14.

To Bryan Donkin, of Fort Place, Bermondsey, gent, j for
a pen upon a new construction. March 14.

To George Nathaniel Pollard, of Queen-street, South-
wark, lapidary ; for certain improvements in machinery for
grinding, smoothing, and polishing plate and other glass
for looking-glasses, mirrors, and various other articles.
March 14.

To Edward Weeks, of Llaveny Hall, in the parish of Hen-
lau and county of Denbigh, in North Wales, gardener; for
a forcing-frame on a new and improved construction, for
raisins; and forcino; of cucumbers, melons, strawberries, and
other fruits and plants. March 17-

To Anthony Thomas, of Duke-street, St. Jameses; for a
method of manufacturing hats, bonnets_, and other articles of
the like description. March 26.

To Benjamin Cook, of Birmingham, manufacturer; for a
new method of making barrels for fowling-pieces, muskets,
pistols, and other similar fire-arms, and ram rods for the
same. March 26.

To John Dickson, of Edward -street, Southwark, engineer;
for an improved method of constructing cocks for stopping
fluids, and which cocks by one motion or operation will per-
mit such fluids to pass in different directions. March 29.

To Charles Dibdin, of Cranford, in the county of Mid-
dlesex, gent. ; for his method of facilitating the learning of
music. April 9.

To Daniel Dering Matthew, of Upper Marylebone-street,

in the county of Middlesex, esq. ; for certain improvements

in the construction of watches and chronometers. April 27.

To William Chapman, of the town and county of New-

pastle-iipon-Tyne, civil engineer; for his methods of con-

vevins;

List of Patents for New Inventions, — Meteorology, 375

veying. coals and other minerals in the working of mines, or
below ground, and of returning the empty vessels and car-
riages. April 27.

To William Bell, of Birmingham, in the county of War-
wick, engineer; for his improvements in making pipes, or
pumps, for conducting water and other liquids. April 30.

To Edward Coleman, Professor at the Veterinary College,
in the parish of St. Pancras, in the county of Middlesex ;
for certain improvements in the construction and application
of a horse-shoe, which will completely prevent several dis-
eases to which the feet of horses are subject, more espe-
cially that very general disease called contraction of the
hoof; and is also particularly adapted for flat convex feet,'
for horses of cavalry, and for hunting ; and for all other
purposes where the loss of a shoe is productive of great in-
convenience. April 30. ^

METEOROLOGY.

Meteorological observations in a tabular form compress so
much information in a small compass, and facilitate com-
parisons in such a manner as to render them highly useful.
In both of these views the following tables cannot but prove
acceptable to many of our readers. The estimate of rain
has been given to the public for several years : Dr. Clarke's
meteorological table did not commence till last June, but
we understand that gentleman means steadily to pursue the
game plan.

To facilitate pursuits of this kind, it is of importance that
such a rain gauge should be provided as may collect all the
snow as well as rain that may fall, and so arranged that the
danger of bursting in a time of frost may be averted. A
correspondent suggests that this object may be gained by ad-
mitting the common gauge into a hot-house kept at the tem-
perature of 60"" of Fahrenheit's thermometer, placing the
large end of the cone at the top, in one of the squares now
. occupied by a pane of glass. Should any better method for
pbtaining such a desideratum present itself to any of our
readers, we shall be happy in being enabled to communicate
\i to the public.

Qtiantity

376 MeleoroIogTf,

Quantity of B-ahiy which fell at the following Places in the
Year 1807. In Inches and Decirfials. By the Rev. J. Blanch-
ARD, of Noifins^harn*.

1807.

u

1

• I-l

U

o
0

it

H

0-82

II

*

a

(J
a

2

"re

1

1

2

To

c

•J

1

Jan.

2-4 '.

0-64

1-S7

1-40 1-50

0 85

3-33

2-73

2 92

2-38

073

FeL:

2-44

l-i8

1-ec

1-79 2-77

2-(M

2 09

3 59

4 59

5 5.S

4 00

1 23

Mar.

0-23

0-50

1-36

044 1-69

1-21

2 60

112

1 52

2-21

0-57

073

Apr.

o\r)

J -02

0-81

0-G7 2-:56

1-77

1-17

3-19

S G6

2-90

1-72

094

May,

5-4V

;^-:^!;

3-47

5-26, 2-80

2 5S

4 70

3 75

3 97

4-47

2 86

5 03

Jujiey

O-.'lS

1-74

1-92

2-8 i! 2-52

M3

2 65

1-25

2 26

2-27

400

3 00

Jail,,

1-6^

O'SS

1-54

2-26 2-25

i-n

2-43

3-50

3 74

4-48

3 43

2-55

''Ug.

3-in

1-94

l-fi4

1-57

1-27

3-31

2- 18

1

2 92

3 49

4 58

1 40

Sf:pt.

•>2£'

2-18

2-17

1-27

1-45

2-86

3 34

> 10-08

10-27

7 92

6-86

1-70

Oct.

2-4S

0-94

0-9J

3- IS

1-78

1-93

1-60

S

6 08

7 09

5-15

1-70

/Vw.

7-54

S'tiS

2-27

1-18

3-83

6-Oy

5 57

4-00

4 93

5 07

5 50

3-33

Dec.

0-8S

0'76

IDS

2-67

0-91

26-9-,

0-8G

3-20

3 26

4-53

2 6-i

0-93

Total,

J9-9S

18-20

20-17

24-45

25-13

30 04

.3701

49 93

52-93

43-69

23 32

A Meteorological Talle from June to Decemler, 1807. By
Dr. Clarke, of Nottingham.

ts^ The followuig observations on the thenuometer are made at 8 A.M

2 P. M and 1 1 P. M and on the barometer at 2 P, M. The former instru-

ment is placed in the open air, exposed to the west, but in a situation sur

rounded by buildings, which prevent any alteration of temperature from cur-

rents of air. The direction of the \

vind is taken from the vane of St. Peter's

church ; and the numbers state how o

ften it has been observed in anv particular

quarter auringf the month. 1

1807.

i KEtCMOMf.Ti-R

BAROMKTER. 1

WEA. 1

WJNDS. 1

1

Is

0

Is

u

>.

csi

^

'hJT;

1

c

> JZ
to '^

0

.1

2 c

0

0)'

c
5

2

1

X

75"

:2

46^

S

0

E

-1

0

20

10

5

C/2
24

iz;

June,

57«-85

100

30 31

29-531 i9 ^-^

•33

37

July,

-0

52

64 00

«

30-50

29 52

29-90

•56

17

H

11

8

55

19

August,

78

^3

S4-98

9 1

30- 18

2959

29 85

34

28

s

11

11

53

18

Seplemier,

67

40

51-93

10

30 i5

29-21

29-69

■55

15

15

5

1

43

41

October,

65

40

53-29

14'

30- 15

29-19

29-83

-51

23

8

8

8

51

26

Xovcmber,

50

z6

88-93

M

30 10

9S 43

29 44

•80

14

16

16

2

41

31

December.

50

24

38-14

13

30 24

29- 11

29 84

■55

25
142

6
72

2
77

9
44

48
315

34

Avr. for |
7 Mont, f

52" -73

—

^978

Totl.

206

* A-ny communications on this branch of Meteorology will be thankfully
received by the Rev. J. Blanchard, Master of the Academy, Nottingham.

METEOilO-

Meteorology.

METEOROLOGICAL TABLE,

Bv Mr. Carev, of the Strand,
, For May 1808.

377

Days of the
rvlouth.

Thermometer.

■^1

c Z

Height of

tnc Barom.

Inches.

Weather.

April 27

May

28
29
30
I
2
3
4
5
6
7
8
9

10
U
12
13
M4
15
16
17
18
19
£0
21
22
23
24
25
26

37"

40

39

41

49

46

59

54

bQ

57

bQ

58

52

51

52

bb

bQ

57

60

69

61

55

46

52

51

60

53

54

54

bl

40"

46

43

50

b9

Q'i

69

73

68

70

69

61

52

57

58

6b

68

76

79

SO

73

58

59

65

64

62

60

65

70

64

38

38

46

47

b9

47

bQ

57

bQ

57

50

45

49

48

54

bb

64

67

68

bb

49

48

-49

bb

54

52

52

b1

bl

29*67
•89
•90
•90
•95
•90
•84
•84
•80
•74

•60
•60
•75

30-06
•20
•38
•19
•19
•02
•06
•15
•21

29*98
•80
•60
•72
•09
•89
•07

o
16
31
46
51
64
59
72
47
62
bl
46
0
27
15
25
45
79
70
92
70
39
45
bb
35
20
19
40
52
15

Kam

Cloudy

Cloudy

Cloudy

Fair

Fair

Fair

Fair

Cloudy

Fair

Fair

Cloudy

Rain

Stormy

Stormy

Cloudy

Fair

Fair

Fair

Fair

P'air

Showery

Fair

Fair

Cloudy

Showery

Showery

Fair

Fair

Showerv

N. B. The Barometer*s height is taken atoi^e o'clock.

C 378 ]

INDEX TO VOL. XXX.

ACABEMT, SLPetershurgg^
^Icetate of Birytes. On decom-
position of by soda 36
j^cidi acetic^ with dcohol. On 64
ylc'idy muriatic. On radical of 105
Mhumen and hark. On 91
Alcohol. Experiments with on
muriates, Sec. 64
Alkalies, Combination of with
oils 42

• . Composition oF, 366

Allen on respiration, 367

Jlfrlcan Society 284

Analysis of chromate of iron 223
Angelica antiseptic to cattle 190
Antiquaries. Society of 182
Ardent siprit made from' leaves
and prunings of vines 226
Astronomy. 67, 127, 227, 347

hangalore. Manufactures at 2^^
Bark and albumen. On 91

Barome'er. Englefield's 46, 176
Barytes, acetate of. On decom-
posing - 36

• , pure. On 40

Basaltes. On 182

£fl/j. On torpidity of, 249
Bermuda islands. Description

^^' 331

Berthollet on time as a chemical

agent 193

Biddle on contraction of mercury

by cold 1 74

Blancbard's meteorological table

Booh. Ntw 1S8, 285, 365
Botany 253, 280, 333

Brandt on calculi 367

Buchamian on uses of steam 225
Buildings in hidia. Internal de-
corations of 221

Calculi. On, 367

Cadet on camphorated water, 66
Calomel. New process for pre-
paring, 93, 133
Caloric. On, 158

Camphorated water. Peculiar
property in, d^

Carefs meteorological tables, 96,
191,288,377
Carnot. On machines, 8, 154,
207, ^10. • Works of, 270
Cattle, remedies for, 94, 190
Cement which resists fire and wa-
ter, 190
Chemical agent. Time one, 193
Chinese radish. Oil of, 372
Chromate of iron. Analysis pf,

223
C/^r-^A meteorological table, 3^6
Cobalt. On, 337

Combustion. On, 158

Comet oi \%o''^. On, 67, 182
Corsica. Account of, 351

Cotton. On dyeing in India, 259,
325, 373 ; culture of, in
France, 373

Cranites. On, 92

Cuvier on elephants, 15

Darcet on decomposition of ace-
tate of barytes, 36

Darw'miana, 109

Davy's bases oT alkalies confirm-
ed, 366.

Diseases, contagious. Fumiga-
tions for, 26

Diseases of plants, a prize ques-
tion, 93

Dispensary Reports, 90, 176, 363

Elephants. Living and fo'^sil, i ,
Englefeld'sh^LYomeier, 46, 176
Epidote. On a variety of, 223
Epps's solar and lunar motions,

347

Ether, acetic. On, 64 3 muriatic,

101', nitric i 177

i^jr^ on musical tenmperament, 3
Fire, to extinguish in the dresses

of females, 173

Firminger on transit of mercuiy

in 1782, 289

Fremy

Fremy on combining

lead and alkalies
Fumigation to destroy infection

I N D

oils with
42

26

Gas-Ughls. On, 92

Geology^ 182, 187,282, 296
Geological Society, i ^3

Gilding, /ill se, to prepare, 221

Hall on oEconomical uses of vine
leaves and prunings, 226

Hawles^s system of music. On, 3

Her schtl on Newton's concentric
rings, 72, 115, 19^. On comet
of 1 807, 182. On Olbers's new
planet, 227

H'tdeSf how dre.^sed in India, 328

Home on functions of the spleen

92

Honvard and Go's new prepara-
tion of calonicl 93, 133

Hume on sulphur as a vermifuge,

Hume on the identity of silex
and oxygen, 165, 274, 356

India. On buildings in, 221 j
manufactures of, 259,322
Indigo cultivated in France, 1 89
Insects. On destroying, 71

Iron, Chromate of, 223

'Jameson on cotemporaneous or
enclosed veins, 1 87 J onminera-
logical maps, 281 j queries, 369

JeweVs new calomel, 133

Kingsley on meteoric stones,

232
Knighton bark and albumen, 91

Lampadius's liquid sulphur. On,

Lrj</. Combination of, with oils,

42
Learned Societies f 91, 182, 280,

366
Leather dressing, in India> 328
Lectures J 28^, 372

E X. 379

Linn a an Soc'ety, 280

Linna^us^s ssxu.d system reform-
ed, 253
Lowe on the comet of 1807, 67

Machines. Essay on, 8, IJ4,
207, 310
Magnesia. Mine of, 208

Mammoth. On the, 284

Mangali on torpidity, 245

Manufactures in India, 259, 322
Mechanics. New power in, 62,
72, 272
Medical Inslitut.ons. Utility of.

Medical Soafty, hondon^ lS6
Mercury. On contraction of, by
cold, 134

Mercury. Transit of, in J 782,

2f89
Meteoric Stones. Remarkable
shower of, , 232

MHeorology, 96, 191, 288, 375
Mica applied to walls as a pig-
ment- 222
Michaux's description of Ber-
muda, 3 31
Mineral waiers. On, 1 29
Mineralogy, 182, 187,282, 296,

Monkeys. On torpidity of, 24 J
Moon. Motions of, 347

Morvcaus fumigations, 26

Mosaic pwuement, 1 82

Mountain barometer. Engle-

field's, 46, 176

Muriatic ether. On, loi

Muriates, metallic, with alcohol.

On, 64

Musical temperament. On, 3

Nautical invention f 191

Nickel. On, 337

Nettles antiseptic to cattle, 1 90
Nezvton^s concentric rings. On,
72, 115, 195
Nomenclature, chemical. On, 320

0/7, manufacture, of in India, 329
Oil of Chinese radish. Uses, 372
Oils.

i8o

I K D £ X.

OUs, Combination of, with lead

and alkalies, 4!^

Olbers's miu planet. Herschel on,

ia;

Optics. Experiments on, 72,11^,

195, 163

Oxidation, Only two degrees of.

Oxygen, identity of, with silex,

165,274,356

Oxymuriat'ic acldiv'itb alcohol, 64

Patents. List of, 94, 19 1, 287,373
Pi rperes* d cwipositiofi of acetate

cfbarytes. On,

36

Ptpys on respiration,

367

Petersburg Academy,

. ^.«3

Potaib. On constituent

princi*-

pies of,

173

Prize questionsy

93

Fyrosoma ailaii.'iciim,

371

Rain. Quantity in 1807, ^"^6

Rampasse's history of Corsica,

Richardson's geological observa-
tions on Ireland, 182
Robiquet on liquid sulphur, 30

on pure barvtes, 36

Rocks. On blasting, 97

Po!off on mineral waters, 132
Royal Sociefy, 91, 18 ,280, 366
Ryul College of Surgeons^ London ,

SchoJcs on caloric, 1^8

SileXf identity of, with oxygen,

l^'5» 2 74' 30
Silk. On dyeing in India, 259,

324
SUHman-'OVi meteoric stones, 232
Skins, how dressed in India, 328
Socieliesy Learnedj gi, 182, 280,
366
Spirits made from leaves and

prunings of vines, 226

Spltcn. On functions of, 92
St, F(?/-7/' J journey lo mount Ila-

mazzo, 296

Stains, to remove from linen, 189

Stanhope Temperament. Ort, ^

Steam employed to heat build-*

ings, and to dry articles of

manufacture, 225

Stones from clouds, 232

Sulphur of Lamp adtus. On, 30

Sulphur a good vermifuge, 7 1

Sulphurous mineral waters. On,

129

Sun. Motions of, 347

Surgical CaseSy 90, 176, ^6^

Siuanivick on new mechanical

power, 62

Taerg on constituent principles

of potash, 173

Tamping. On blasting rocks by,

97

Tanning In India> 328

7"^ wK/cff'i Dispensary reports, 90^

176,363

Taunton on medical institutions,

i7r
Taylor on blasting rocks, 97
Thi-Tiard on cihers^ 64, loi, 177
Tkornton^s reformed sexual sy-
stem of Linnaeus, 253
Time^ influence of, as a chemical

On, 245
271

agent.
Torpidity of animals.
Travels,

University of Edinlurgh,

34S

Varioiite. On, 304

Faiiquelin on liquid sulphur 30
Fermifuge. A good one, 7I
Vidal on new power in me-

chanics.

12, 272

Vines. G^'.conomical uses of prun-
ings and leaves of, 226

Walker on apparent magni-
tudes, 163
JVernerian Society, 186, 281,368
^7/;«OT(^ on mineral \^aters, 129
iVilna, university of, 93
IVool. New method of scouring 94
Zoophit. s. New species of, 3 7 J
Zoysiti, a variety of epidote, 223

END OF THE THIRTiETH VOLUME.
printed by liirhard Tgijl</r rtnd Co., Shoe Lane.

,^'

SirH.C.En^leAdds.Moiwtam3aranuttr, ^hih-^-^oLUZ.Fl.I.
hyTkof Jones of Mount Street.

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FkdM^yclXKXM.11.

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I'hil.lia^.Vol.XXXJnLV:

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