S.U&

JOURNAL

OF

NATURAL PHILOSOPHY:
CHEMISTRY,

AND

THE ARTS.

VOL. V.
3ittustrateu toitfc <£n0ratimg0;

BY WILLIAM NICHOLSON.

LONDON:

PRINTED BY \V. STRATFORD, CROWN-COURT TEIYIPLE-BAR FOR

THE AUTHOR, No. 10, SOHO-SQUARE

AND SOLD BY

G. and J. ROBINSONS, PATERNOSTER *ROW.
/ 1 S03 .

Alio*

ADVERTISEMENT.

JL HE Authors of Original Papers in the present Volume,
are John Dal ton, Esq. ; Mr. J. Andrew; Sir A. N. Edel-
crantz; Samuel Day, Esq.; The Right Honourable the
Marquis of Exeter ; W. N. ; Mr. Robert Harrup ; J. B. ;
The Rev. Wm. Gregor; Mr. Benjamin Hooke ; Mr. John
Gough ; and Mr. Frederick Accum. Of foreign Works,
M. Proust ; Joses ; Vauquelin ; Trousset ; Lagrave ; Darcet ;
Van-Marum ; Vassali Eandi ; Carbonell ; Parmentier ; Cadett;
Boullay ; Ritter and Curaudau. And of English Memoirs
abridged or extracted, B. H. Latrobe, F. A. P. S. ; Mr.
Robert Dossie; Thomas Eccleston, Esq. ; Mr. John Webb;
Mr. Richard Knight ; The Right. Hon. Sir J. Banks, Bart.
P. R S. ; William Herschell, L. L. D. F. R. S. ; Richard
Kirwan, L. L. D. F. JL S. ; Richard Chenevix, Esq. F. R.S.;
John Templeton, A. L. S. ; Benjamin Smith Barton, M D ;
Philip Crampton, M. D. ; H. Davy, Esq.; Mr. William
Henry ; M. Komarewski ; and Charles Hatchett, Esq.

Of the Engravings the Subjects are, 1. An improved
Gun-Lock, by Mr. John Webb. 2. An Apparatus for spliting
Logs of Wood, by Mr. R. Knight. 3. Mr. Eccleston's Peat-
borer. 4. The Ornifcus Prasgustator, as it resides in the
Mouth of the Bay Alewife. 5, Outline Drawing of the
Clupea Tyrannus or Bay Alewife. 6. Figure to illustrate a
new Method of computing the Longitude, by Mr. Andrew.
7. Two Plates of Figures illustrative of Dr. Herschell's Memoir
on the Structure of the Heavens. 8. Sir. A. N. Edelcrantz's
new Statical Lamp. 9. An Ancient Magazine Gun for
quick firing. 10. An Ancient Lock of thirteen hundred
Combinations. 11. An Apparatus for Distillation, by Sir

A.N.

ADVERTISEMENT.

A.N. Edelcrantz. 1 2. A Galvanic Apparatus by Mr. Davy#
13. An Electrical Battery of Talc. 14. A Compound Arti-
ficial Magnet of four Poles. 15. The Swedish Telegraph,
invented by Sir A. N. Edelcrantz. 16. An Apparatus for
determining the comparative Wear of Gold, by the Hon. H.
Cavendish, Esq. 17. Mr. Henry's Apparatus for measuring
the Absorption of Gafes. 18. A Subterraneous Graphome-
ter, by M. Komarzewski.

Soho Square, August, 1803.

TABLE OF CONTENTS

TO THIS FIFTH VOLUME.

MAY 1803^

Engravings of the following Objecls : 1. An improved Gun Lock, by Mr. John
Webb; 2. An Apparatus for fplitting Logs of Wood, by Mr. R. Knight;
3. Mr. Ecclefton's Peat Borer; 4. The Onifcus Praeguftator, as it refides in
the Mouth of the Bay Alewife j 5. Outline of the Clupea Tyrannus or Bay
Alewife; 6. Figure to illuftrate a new Method of computing the Longitude,
by Mr. Andrew.

I. A Drawing and Defcrlption of the Clupea Tyrannus and Onifcus Praeguf-
tator. By Benjamin Henry Latrobe, F. A. P. S. - - - I'

II. The Principles on which the Purification of Fifh-oil may be performed, and
of the Ufes to which it is applicable. By Robert Doffie. - j

III. An EfTay on the Fecula of Green Plants. By ProfeiTor Prouft. 16

IV. Defcription of a Borer for draining Boggy land. By T. Ecclefton, Esq. 28

V. Defcription of an Improvement in the Gun-Lock by which the cafual Dif-
charge of the Piece is prevented. By Mr. John Webb. 29

VI. Defcription and Account on a fimple Apparatus for breaking-up Logs of
Wood by the Explofion of Gunpowder. By Mr. Richard Knight. 3i

VII. Letter from Mr. Dalton, containing Obfervations concerning the Deter-
mination of the Zero of Heat, the thermometrical Gradation, and the Law
by which denfe or non-elaftic Fluids expand by Heat. 34

VIII. Memoir containing the Phyfical and Chemical Examination of the Teeth.
By Cit. JoiTes of Rennes. - ------ S6

IX. A new Method of clearing obferved Lunar Diftances of the Effects of Pa-
rallax and Refraction, for the Purpofe of determining the Longitude at Sea or
Land. By Mr. J. Andrew. Communicated by the Author. - 43

X. Analyfis of the Propolis or Maftic of Bees. By Cit. Vauquelin. 48
XI- Memoir on the cutaneous aeriform Tranfpiration. Read at the public

Sitting of the Society of Health, at Grenoble, the 4th Frimaire, in the Year
11. By Cit. Trouffet, M. D. &c 50

Scientific News, 54, — Decree of the French Government relative to the new Or-
ganization of the National Inftitute, ib. — Galvanic information, 58. — Prize
queftion, 59, — Hermaphrodite fifli, 60. — Experiments calculated to prove that
the Laws of Galvaniim appear to differ from thole of Electricity. By La-
grave, Member of the Galvanic Society, ib. — Galvanic Experiments, tending
to afcertain the Exiftence of two Fluids in the Animal Economy, the one pofi-
tive and the other negative, which, by their Union, appear to produce the
Agency of Vitality. By Lagrave, Member of the Galvanic Society. 62

Account of New Books, 63. — Tranfactions of the American Philofophical So-
ciety held at Philadelphia for promoting uleful Knowledge, ib. — The Che-
mical Pocket Book, or Memoranda Chemica j arranged in a Compendium
of Chemiftry. By James Parkinfon, Holborn. 64

JUNE

ii CONTENTS.

JUNE 1803.

Engravings of the following Objects : 1. 2. Two Plates of Figures illuftrativeof
Dr. Herfchel's Memoir on the Structure of the Heavens j 3. The Chevalier
D'Edelcrantz's New Statical Lamp, in which the Oil is kept conftantly at any
required Height, without any Fountain Refervoir j 4. An ancient Magazine
Gun for quick firing, communicated by the Right Honourable the Earl of
Warwick.

I. A Report of the State of His Majefty's Flock of Fine-wooled Spanifh Sheep
during the Years 1800 and J 801 j with ibme Account of the Progrels that has
been made towards the Introduction of that valuable Breed into thofe Pai >f
the United Kingdom where fine Clothing Wools are grown with Advantage.
By the Right Hon. Sir Jofeph Banks, Bart. P. R. S. &c. &c. - 65

II. Defcription of a New Procefs of Refining. By Cit. Darcet, Nephew. 70

III. Remarks on the Conlbuclion of the Heavens. By William Herfchel,
LL. D.F.R. S. From the Philof* Tranfa6tions, 1802. - - 75

IV. Defcription of a New Statical Lamp., which of itielf raifes and keeps the Oil
at a conftant Height. By M. D'Edelcrantz, of Stockholm, Member of feveral
Academies and Literary Societies, Knight of the Order of the Polar Star,
&c. - 93

V. On Oily Hidrogen. By ProfefTor Prouft. 97

VI. Letter from Fortis to J. C. Delametherie, on a Shower of Mud which fell
at Ud na. 101

VII. Letter from M. Van. Marum to M. Berthollet. Containing an Account
of ibme Experiments, mewing the Method of extinguiihing violent Fires with
very fmall Quantities of Water, by Means of Portable Pumps. - 103

VIII. Report, prefented to the Clafs of Accurate Knowledge of the Academy of
Turin, in the fitting of the 2d Nivofe, (Dec. 23, 1802) in the Year II, on
the Action of Galvanifm, and on the Application of this Fluid, and that of
Electricity, in the Healing Art, by Antoine-Marie Vaffaii Eandi. 109

IX. Account of Two Mufquets of peculiar C on fl.ru cl ion for the Purpofe of quick
firing.— W. N. 116

X. Of Rain. By Richard Kirwan, LL. D. F. R. S. Prefident of the Royal
Irifh Academy, &c. - --120

XI. Obfervations and Experiments undertaken with a View to determine the
Quantity of Sulphur contained in Sulphuric Acid ; and of this latter contained
in Sulphates in general. By Richard Chencvix, F. R. S. and M. R. I. A. 126

Scientific News, 133. — Improvement on Lamps, ib.— Improvement on the Mode
of Watching Cities, ib. — Some Account of a pretended new Metal offered for
Sale and examined by Richard Chenevix, El'q. 13(5.— A new Method of Paint-
ing, propofed by M. Carbonell, a Spanifh Pbyfician, capable of being advan-
tageoufly fubftituted for Painting in Diftemper. - - - ■ 139

Account of New Books, 142. — Report of the intended North London Canal
Navigation ; with general Eftunate, &c. &c. ib. — Defcription of an improved
Armillary Sphere exhibiting at one View the true Solar, or Newtonian Syltem,
agreeably to that Order, Harmony, Beauty, and Variety obfervabJe in the
Heavens j whereby the Science of Aftronomy will be familiarly exempli-
fied, 143.— A Theory of Winds and Waves, ib. — New Galvanic Experi-
ments 144

JULY

CONTENTS. iii

JULY 1803.

Engravings of the following Objects : 1. An Ancient Secret Lock of Thirteen
Hundred Combinations; 2. An Apparatus for Diitillation, by Sir A. N.
Edelcrantz; 3. Galvanic Apparatus, by Mr. Davy; 4. Electrical Battery of
Talc; 5. Compound Artificial Magnet of Four Poles; 6. The Swedifh Tele-
graph invented by Sir A, N. Edelcrantz.

I. On the Naturalization of Plants. By John Templeton, A.L. S. From the
Irilh Traniaaions, Vol. VIII. - - 145

II. A Method of remedying certain Inconveniences arifing from the Inequality
of Heat in large Diftillatiom By Sir A. N. Edelcrantz. - 156

III. Account of a Time-Piece for regiftering the Attendance of Watchmen,
and for fimilar Purpofes; conftru6led by MefTrs. Boulton and Watt, for the
Rt. Hon. the Marquis of Exeter. In a Letter from his Lordfhip. 158

IV. Some Account of the Poifonous and Injurious Honey of North America.
By Benj. Smith Barton, M. D. i$y

V. On the Compofition andUfeof Chocolate. By Citizen Parmentier. 175

VI. On the Caules by which the Oxigen of the Atmofphere is fupplied or reno-
vated. In a Letter from Mr. RoDert Harrup. - - - 184

VII. Report on a Memoir fent to la Societe Libre des Pharmaciens, of Paris.
By Cit. Robert, Chief Phyfician to the Hofpital of Humanity at Rouen. By
Citizens C. L. Cadet and Boullay. - - - - 189

VIII. Defcription of a Telegraph ufed in Sweden.' Conftrucled by Sir A. N.
Edelcrantz, Counfellor of the Chancery, and private Secretary to the King of
Sweden, Archivift of the Orders of His Majefty, and One of the Eighteen
Members of the Swedifh Academy. From the Copy of a Treatife on Tele-
graphs, communicated by the Author. - - - -193

IX. Additional Obfervations on the Probability that the Eruptions of Lunar Vol-
canos may lbraetimes reach the Earth. By a Correfpondent. - 201

X. Defcription of an Ancient Lock of Combination. W. N. - 203

XI. Analyiis of a Pulmonary Calculus. By Philip Crampton, M. D. Member
of the Royal College of Surgeons in Ireland. Communicated by the Honour-
able George Knox, F. R. S. M. R. I. A. &c. - /- - 205

XII. Of the State of Vapour fubfifting in the Atmofphere. By Richard Kirwan,
Efq. LLD. F.R.S. andP.R. I. A. - ,- - - 207

XIII. Notices concerning fome Philofophical Apparatus. ---Electrical Battery of
Talc— Complex Horfefhoe Magnet.— -Mr. Davy's Apparatus, &c. 216

XIV. Experiment to determine the relative Quantities of Light afforded by
Candles of different Dimenfions, in a Letter from a Correfpondent. 219

Scientific News, 220. — On the Nutriment to be obtained from Bones, ib. — Me-
thod of preparing Muriatic Ether with fimple Acid ; by M. BafTe, Apothecary
at Hameln, 221. — On the Effects produced by the Decortication of Trees. 222

Account of New Books, 223. — Refearches into the Properties of Spring Water,
with Medical Cautions (iiluftrated by Cafes) againft the Ufe of Lead in the
Conftruclion of Pumps, Water Pipes, Cifterns, &c. ib. — Uieful Hints to thofe
who are afflicted with Rupturer; on the Nature, Cure, and Confequence of
the Difeafe ; and on the Empirical Practices of the piefent Day. 224

AUGUST

ir CONTENTS.

AUGUST 1803.

Engravings of the following Objects : 1 . An Apparatus for determining the
comparative Wear of Gold. By the Hon. H. Cavendifh, Eiq. j 2. Mr.
Henry's Apparatus for meafuring the Abibrption of Gafes j 3. A Subterra-
neous Graphometer, by M. Komarzewfki.

I. On the Production of Sulphate of Magnefia from the Aflies of Pit-Coal, with
Remarks on the Efflorefcence of the fame Salt, obferved by Dr.Boftock. In a
Letter from the Rev. William Gregor. - 225

II. The Method of making Artificial Yeaft in Germany and Sweden. Commu-
nicated by Sir A. N. Edelcrantz. 228

HI. Remarkable Fact of the Difappearance of a Mixture of Oxigen and Hy-
drogen, at the common Temperature over Water j inducing the Probability
that Water may be formed at low Heats. In a Letter from Mr. B. Hooke. ib.

IV. Experiments on the Quantity of Gafes abforbedby Water, at different Tem-
peratures, and under different PrefTures. By Mr. William Henry. 229

V. Of the State of Vapour fubfifting in the Atmofphere. By Richard Kirwan,
Ei'q. LLD. F. R.S. and P. R.I. A. ... 242

VI. Experiments and Gbfervations in Support of the Theory of Ventriloquifm
which is founded on the Reflection of Sound. In a Letter from Mr. John
Gough. - _..--- 247

VII. Examination of the fo called Salt of Bitumen, the Bit-Nobin of the Hin-
doos. By Frederick Accum, Practical Chemift and Teacher of Che-
miftry. - - - - - - - 251

VIII. Experiments on the Invifible Rays of the Solar Speclrum. By M. Rit-
ter, of Jena. Communicated by M. Vicktred, Doctor in the Univerfity of
Copenhagen, to the Editors of the Bulletin des Sciences at Paris, No. 73. 255

IX. An Account of fome Experiments and Observations on the ConfKtuent
Parts of certain Aftringent Vegetables; and on their Opeiation in Tanning.
By Humphry Davy, Ei'q. Profeflbr of Chemiftry in the Royal lnftitution. 256

X. Memoir on the Nature and the new Properties of the Pruific Acid. By
Cit. Curaudau, correfponding Member of La Societe libre des Pharmaciens
de Paris. _.----. 277

XI. Defcription of the Subterraneous Graphometer invented by M. Komar-
zewfki, F. R. S. and prefented to &e National Inftitute of France. 283

XII. Experiments and Observations on the various Alloys, on the Specific Gra-
vity, and on the comparative Wear of Gold. Abftracled from the Memoir of
Charles Hatchett, Efq. F. R.S. ----- 285

XIII. Obfervations of the Tranfit of Mercury over the Difk of the Sunj to
which is addtd, an Investigation of the Caufes which often prevent the proper
Action of Mirrors. By William Herfchell, LL.D. F. R, S. - 304

A

JOURNAL

OF

NATURAL PHILOSOPHY, CHEMISTRY,

AND

THE ARTS,

MA Y, 1803.

ARTICLE I.

A Drawing and Defcription of the Clupea Tyrannus and Otiifcus
Prccgujlator. ^Benjamin Henry Latrc-be, F.A.P.S*

To Thomas P. Smith, one of the Secretaries of the American
Philofophical Society.
SIR,

1 BEG leave, through your means, to communicate to the Intfoduaor? tt*
American Philofophical Society, an account of an infect, whofe marks#
mode of habitation, a£ leaft during fome part of his life, has
appeared to me one of the moll: lingular, not to fay whimficalj
that can be conceived.

In the month of March 1797, illnefs confined me for feveral
days, at the hoiife of a friend on York river in Virginia, du-
ring his abfence. My inability to move further than to the
fliore of the river, gave me leifure to examine carefully, and
in more than an hundred inftances, the fa& I am going to
mention.

Among the fifh that at this early feafon of the year refort to Defcription of

the waters of York river, the alewife or oldwife, called the ^e £ A cf]cdr

r the bay aletvije»

* From the Tranfaaions of the American Phil. Society, V. 77.
Vol. V,— May, B bay*

Largtf infeft rc<
fident in the
mouth of the
Iftl

thought to be eY«
lential to its life
and not fepara-
rable without
deftrudlion ci-
ther of the fi/h,
*r ofitfelf.

Delineation.

Befcnption of
Linnaeus under
the name of
6mfcus Pbjfodv

DESCRIPTION Of THE CttfPEA TYRANNCi.

bay-alewife, (clupea nondefcripta) Arrives in very confiderable*
/hoals, and in fome feafons their number is almoft incredible'.
They are fully of the fize of a large herring, and are princi-
pally diftinguifhed from the herring, by a bay or red fpot above
the gill-fin. (fee the drawing) They are, when caught from
March to May, full-roed and fat, and arc at leaft as good a
fifh for the table as the herring.

In this feafon, each of thefe alewives carries in her mouth an
infect, about two inches long, hanging with its back down-
wards, and firmly holding itfelf by its fourteen legs to the pa-
late. The fiihermen call this infect the loufe. It is with diffi-
culty that it can be feparated, and perhaps never without in-
jury to the jaws of the fifh. The fiihermen therefore confider
» the infect as eflential to the life of the filh ; for when it is taken
out, and the fifh is thrown again into the water, he is inca-
pable of fwimming, and foon dies. I endeavoured in nume-
rous in fiances to preferve both the infect and the fifh from in-
jury, but was always obliged either to deflroy the one, or to
injure the other. I have fometimes fucceeded in taking out
the infect in a brifk and lively ftate. As foon as he was let
free from my grafp, he immediately fcrambled nimbly back
into the month of the fifh, and refumed his pofitkm. In every
inftance he was difguftingly corpulent, and uupleafant to han-
dle ; and it feemed, that whether he have obtained his port
by force, or by favor, whether he be a mere traveller, or a
conflant refident, or what etfe may be his bufinels where lie
is found ; he certainly has a fat place of it, and fares lump*
tuoufly every day.

The drawings annexed to this account were made from the
Jive infecl, and from the fifh out of whofe mouth he was taken.
I had no books to refer to, then ; but examining the Syfte?ua
Naturaof Linnaeus, I was furprized to find fo exact a defcrip-
tion of the infect as follows (fee Salvii editio, Holmia 176*3,
p. 10G0. alfo Trattner's Vienna edition, fame page).
*' Infecl. apt. Oniscus, Pedes XIV.
Antenna fetacea
Corpus ovale.
0. Pbjfodes, ubdomine fubtus nudo, Cauda ovata..
Habitat in pelago \ corpus prater caput, tt caudam ultimam,
e.r feptem fcgmentis trunci, et quinaue Cauda. Antenna utrinquc
duo, brevet i Cauda folium terminate omni 'no ovatiun ; ad latera

utrinquc

DESCRIPTION OF THE CLUPEA TYRANNUS. $

ktrinquefubtus audturh duobus petiolis diphyllis, foliolis lanceola*
tis, obtufis, cauda brevioribus. Cauda articuli fubtus obtecli nu-
merous veficulus longitudine cauda."

From the particularity with which the onifcus phyfodes is
tlefcribed by Linnaeus, it is evident that he had the infect be-
fore him, or a defcription by an attentive obferver. It appears
alfo from the «* Habitat in pelago" that the O. Phyfodes, if But differing in
this be the infea, is found detached from his conductor. JaJyjjfjJ-
There are a few points in which the O. Phyfodes differs from the ocean.
my infed. I did not obferve the antennae, perhaps for Want
of fufficient attention, or of a microfcope. The petioli of the
tail were not, to appearance, two-leaved, and I am certain
that the fegments oi the tail, and the tail itfelf, were without
the veficuli longitudine cauda.

There are many circum fiances, to afce'rtain which is effen- Whether the

tial to the natural hiftory of this infefi. The fifti whofe mouth !"fe^ b.e c<?n"
i-ii- iir • • i , it- ftantly in the

he inhabits comes, about the lame time with the chad^ into mouth of the

the rivers of Virginia from the ocean, and continues to travel fi&t &c*
upwards from the beginning of March, to the middle of May ;
as long as they are caught upon their paflage up the river,
they are found fat and full of roe. Every filh which I faw had
the onifcus in his mouth ; and I was aflured, not only by the
more ignorant fifhermen, but by a very intelligent man who
came down now and then to divert himfelf with flfliing, that,
in 40 years obfervation * he had never feen a bay ale wife with-
out the loufe. The chad begin to return from the frelh water
lean and Jhotten, about the end of May and beginning of June,
and continue defcending during the remaining fummer months.
No one attempts then to catch them, for they are unfit for the
table. Whether the bay alewife returns with the chad, I
could not learn, but it is certain that after June it is not thought
worth the trouble to catch them. No one could tell me poji-
tively whether the onifcus flill continues with them, but it was
the opinion of my informant, that, lilce every other parafite,
he deferts his prote&or in his reduced ftate, for he could not
recollect that he had ever feen him in the mouth of thofe acci-
dentally caught in the feine in July or Augufl.

I confider, therefore, the natural hiftory of the onifcus, or be the fame
which I now communicate, as very imperfect ; and it were *s. th<; om^us of
to be wifhed that fome lover of natural fcience would follow
up the enquiry, by endeavouring to afcertain whether hecon-

B 2 tinue

£ DESCRIPTION OP THE CLL'PEA 1YHA.NNX/S.

tinue with, or quit the fifli before his return to the ocean, and

alio whether he be the onifcus phyfodes of Linnaeus, qui

habitat in pclago.
Proposed name. Should he be an infect hitherto undefcribed, 1 think he

might be very aptly named onifcus pr&guflator.

The bayalcwife The bay alewife is not accurately defcribed in any ichthyo*

not accurately logical work which I have (een ; nor can I from my drawings,
defcribed. ? . , , » , , . , r ?

which were made with a very weak hand, venture a detcnp-

tion. From his having a regular praeguftator, I would fuggeft

that he ought to be named clupea tyrannus*

teaches on the The onifcus refembles the minion of a tyrant in other re-«

wiifcui. fpects, for he is not without thofe who fuck him. Many of

thofe which I caught had two or three leaches on their bodies,

adhering lb clofely, that their removal coil them their heads.

Moft of the marine onifci appear to be troublefome to fome

one or other fifli. The onifcus ceti is well known as the

plague -of' whales, and many of the reft are mentioned in

jLinmeus and Gmelin, as peftes pifcium.

BENJ. HENRY LATROBE, F. A. P. S.

Qu. If men- P. S. A gentleman well fkilled in entomology informs me

tioned in Block's tnat jie believes, that io Block's Hiftory of Fifties, a work not
to be had in Philadelphia, this onifcus is mentioned. But,
from a late examination of Gmelin and Fabricius, I am con-
vinced that the onifcus praeguftator is a fpecies not hitherto
accurately defcribed — Gmelin had probably feen the Linnaean
infect, having changed the antenna utrinque duo, to antennis
quaternis, and left out moft of the long defcription given by
Linnaeus. Neither he, Linnaeus, nor Fabricius, mention the
circumftance of habitation in the mouth of the filh, and the
induftrious and copious Fabricius, who having changed the
names of the genera, calls him cymothoa phyfodes, copies
the defcription of Gmelin, excepting the mention of the four
antennae, which in hi& arrangement form a character of the
genus, /

Thd

PURIFICATION OF FISH-OIL. 5

The Principles oil which the Purification of Fijh-oil may be per*
formed, and of the Ufes to which it is applicable. By Robert
Dossif. *.

1 HAT the fetid fraell of fiuVoil is chiefly owing to putre-Fator of fifh-
faclion, it is unneceflary tp fhow ; but though this be the !„t££a™n and
principal eaufe, there is another likewife, which is, uftion empyreurna.
pr burning the oil, occasioned by the ftrong heat employed
for the extracting it from the blubber of the larger fifh, and
which produces a ftrong empyreumatic fcent that is not
jalways to be equally removed by the fame means as the putrid
fmell, but remains fometimes very prevalent after that is taken
away.

In order to the perfect edulcoration of oils, there are con- The fa™
fequently two kinds of fetor or ftink.to be removed, viz. [^jf j^0*
the putrid, and the empyreumatic.; and the fame means do
not always equally avail againft both.

The putrid fmell of fifh-oil is of two kinds ; the rancid, The oil itfelf

■which is peculiar to oils j and the common putrid fmell, which ™nyci^c°™eit

is the general efTe£t of the putrefaction of animal fluids, or of may putrefy as

the vafcular folids, when commixed with aqueous fluids. t0,us mixture of

. r n .. ,, other matters.

Fifh-oil has not only rancidity, or the firlt kind of putrid Fifh-oil has both

fmells peculiar to oils, but alfo the fecond or general kinds ; thefe putrid

,..'„, n . • - t • i , i ,- fmells. It w

fts the oil, for the molt part, is commixed with the gelatinous tains geiat-me
humour common to all animals, and fome kinds with a pro- and rile.
portion of the bile likewife ; and thofe humours putrefying
combine their putrid fcent with the rancidity of the oil, and,
jn Cafes where great heat has been ufed4 with that and the
empyreurna alfo.

The reafon of the prefence of the gelatinous fluid in fifli- The gelatine Is
oil is this : that the blubber, which con fifts partly of adipofe j. °J^cveJ£™*
veficles, and partly of the membrana cellulofa, which cpn-&c.
tains the gelatinous fluid, is, for tlie moft part, kept a cpn-
fiderable time before the oil is feparated from it, either from
the want of convenient opportunities to extract the oil, or in
order to the obtaining a larger proportion ; as the putrid

* Communicated to the Society for the encouragement of Arts .
long ago, but now publifhed by them in the original form.

efTervefcenc^

con,-

6 PURIFICATION PF FISH-OIt.

effervefcence which then comes on, rupturing the veficlcs,
makes the blabber yield a greater quantity of oil than could
be extracted before fuch change was produced ; and the
veficles of the tela cellulofa, containing the gelatinous matter,
being alfo burft from the fame caufe, fuch matter being then,
rendered faponaceous by the putrefaction, a part of it mixes
intimately with the oil, and constitutes it a compound of the
proper oleaginous parts and this, heterogeneous fluid.
How the bile The prefence of the bile in fifti-oil is occasioned by its

mixed. being, in many cafes, extracted from the liver of the fifh $

which is not to be fo profitably done by other means as by
putrefaction ; and the bile being confequently difcharged,
together with the oil from the veflels of the liver containing
them, combines with it, both from the original faponaceous
property of bile, and from that which it acquires by putre^
faction.
Train oil i$ This holds good particularly of the cod-oil, or common

particularly train, brought from Newfoundland ; which, from its high
yellow colour, vifcid confidence, and repugnance to burn-
ing well in lamps, manifefts fenfibly the prefence of bile and
the gelatinous fluid ; which latter, by the faponaceous power
of the bile, is commixed in a greater proportion in this than
in any other kind of fifti-oil,
Perfeft oils are A tendency to putrefy, or at moft but in an extremely flow
^utrcf1^0^10 manl^er' is not an abfolute property of perfed oils in a fimple
or pure ftate ; but it is a relative property dependant upon
their accidental contract or commixture with the aqueou*
fluid. This is evident from the cafe of oils concreted into a
febaceous form | which being perfectly oleaginous and un-
combined with any water, except fuch as enters into their
unlefs water be component parts will not putrefy unlefs water, or foraething
prefent, containing it, is brought in contact with them, But the

fluid animal, and moft vegetable oils, being compounded
pf perfect oils with other mixed fubflances, either fub-
But moft oils oleaginous or gelatinous, have always a putrefcence per fe,
will putrefy or tendency to putrefy, without further admixture of aqueous
moifture. This commixture of heterogeneous matter in fifh-
pij, particularly of the gelatinous fluid and bile, gives rife to
even after edul- a further principle of purification thanjlmple edulcoration, or
coratiom fae removing the fetor; for the prefence of fuch humours in the

oil renders it fubjedi to a fecond putrefcence per fe, fiippofing

the

TUR1FICATI0N OF FJSH-OIL. *J

the fir ft corrected ; makes it unfit for the purpofe of the woollen
manufacture, as the heat through which this is in fome cafes
employed, caufes this matter to contract a moft difagreeable
empyreuma. It alfo prevents its burning in lamps, as well
from its vifcidity as from the repugnance which the prefence
of water gives to all oleaginous matter. It is therefore neeef-
iary to free the oil from this heterogeneous matter; after
which it can be fubject only to the rancid putrefcence, or
that which is proper to oils as fuch.

The fubftances which have been or may be applied to the Enumeration of
removing or preventing the effects of putrefcence, are, acids, p°r|^g ^^
alkalies, metallic calces, neutral falts, ethereal and eflential Acids, alkalies,
oils, vinous fpirits, water, and air. With refpeft to acids, J*jJe \£%f
though they may be applied with effect to the removal or alcohol, waterj
prevention of putrefaction in mixed animal and vegetable3'1'
fubftances, yet they have not the fame efficacy when emr eligible,
ployed in the cafe of oils j for in a fmall proportion, without
the fubfequent aid of alkalies, they rather increafe than
diminifh the foetor, and in a large proportion they CQagulatp
the oils, and change their other properties as well as their con-
fidence. Though they might therefore be employed with
the affiftance of alkalies, yet requiring a more expenfive and
complex procefs, and not being moreover necelfary, as the
fame end may be obtained by the ufe of alkalies only, they
may be deemed improper for the purification of animal oils
for commercial purpofes. Alkaline fubftances, both falts but alkalies are
and earths, are the m oft powerful inftruments in the edul-tefl>
coration of oils ; but as their action on putrid oils, and the
method of applying them to this end, are not the fame in.
both, it is proper to confider them diftin&ly.

Of alkaline falts it is the fixed kind only which are proper Fixed alkaline
to be ufed for the edulcoration of oils. Fixed alkaline falts, ca^onates in-
jn a diflblved ftate, being commixed with putrefying animal procefs jC P°
fubftapcps, appear to combine with putrid matter, and mixing
with fome of the principles, form inftantly volatile alkaline
falts. On the lefs putrid they feem to a&, after their com-
bination, by an acceleration of the putrefcent action, till
they attain the degree which produces volatile falts. This is
evident by the fenfible pijtrid ferment and fmell which appear
after their commixture ; but which gradually abating, the qil
is rendered fweeter, much lighter-coloured and thinner.

PURIFICATION OF FISH-OIL.

and arc very Their great ufe in the edalcoration of fifti-oil arifes, there-

|f f|£einJUr,fy"fore> from their converting fuch parts of the gelatinous fluid
and bile as are highly putrefied, inftantly into volatile falts,
and caufing a rapid putrefaction of the other parts ; by which
but they do not means the oil is freed from them by their diflipation. They
remove empy- j0 not^ hovvever> equally act on the parts of the oil on which
the empyreumatic fcent depends, unlefs by the afliftance of
heat; for when they are commixed with the oils without heat,
in proportion as the putrid fmell diminilhes, that becomes
more fenfibly prevalent. The ultimate a6tion of lixiviate
falts on animal oils, except with refpect to the empyreuma,
feems to be the fame either with or without the medium of
heat j for the fame urinous and putrid fmell, gradual diminu-
tion of the colour, and fetid fcent, happens in one cafe as in
the other, except with regard to the acceleration of the
changes ; and fuch falts, where the purification is required
to be made in a great degree, are a neceflary means, as they
are more effectual than any other fubftance that can be em-
ployed.

The ufe of lixiviate falts alone is not, however, the moft
expedient method that can be purfued for the edulcoration
of oils, for feveral reafons. If they be ufed alone, cold, in
the requifite proportions, they coagulate a confiderable part
of the oil, which will not again feparate from them under a
very great length of time ; and when they have deftroyed
the putrid fcent, a ftrong bitter empyreumatic fmell remains.
The fame inconvenience, with relation to the coagulation of
part of the oil, refults when they are ufed alone with heat.
The fuper-addition of common fait, (which refolves the
coagulum and counteracts the faponaceous power of the
lixiviate fait, by which the oil and water are made to combine)
is therefore neceflary ; and the expence arifing from the larger
proportion of lixiviate fait, requires it to be employed if no
Alkaline earths, other alkali be taken in aid, and renders the junction of alkaline
earths with it extremely proper in the edulcoration of oils
Lime >s good but for commercial ufes. Lime has alfo an edulcorative power
it coagulates. on an;ma{ 0j|s . ?t jt has ajf0 f0 ftrorig a coagulative aftion,

that the additio M of a large proportion of alkaline falts be-
comes, when it is ufed, neceflary to reduce the concreted
dil to a fluid ftate ; and therefore this fubfbmce alone is not
proper for that purpofe. The combination of lixiviate fait

with

The alkaline
carbonates
render part of
the oil folid j

but this is cor-
rected by com-
mon fait.

as do alfo foap

PURIFICATION OV FlSH-OIL. §

with lime/ or the folution commonly called foap-lye, has an
effectual edulcorative action on fetid oils ; but it makes a trou-
blefome coagulation of part of the oil, if no common fait be
employed, and muft be ufed in fuch large proportion, if no
alkaline earth be added, as renders the method too expenfive.

Lime has a power of combining with and abforbing the Lime alone is
putrid parts of the gelatinous fluid and bile, when commixed imPr0Peri
with oil ; and effects, either with or without heat, a confider-
able edulcoration of fetid oils ; but it combines fo ftrongly
with them, either cold or hot, that the feparation is difficult to
be effected, even with the addition of brine ; and the oil,
when a large proportion of it is ufed, can fcarcely be at all
brought from its concreted to a fluid ftate, but by an equiva-
lent large proportion of lixiviate fait : the ufe of lime therefore,
alone, is improper, or even in a great proportion with other
ingredients. But when only a leffer degree of edulcoration is unlefs in fmal!
required, a moderate quantity, conjoined with an equal orPr.°Porj)0" and
greater weight of chalk, which affifts its feparation from the
oil, may, on account of its great cheapnefs, be employed very
advantageoufly : it will in this cafe admit of precipitation from and brine,
the oil by the addition of brine. It may be alfo expediently
ufed, when lixiviate fait is employed with heat for the moll:
perfect purification of oils ; for it will in that cafe give room
for the diminishing of the quantity of lixiviate fait, though the
proportion be neverthelefs fo reftrained as not to exceed what
the proportion of lixiviate fait (juft requifite for the edulcora-
tion) can feparate from the oil.

Chalk has an abforbing power fimilar to lime, but in a lefs Chalk lefseflet-
degree on the putrid fubftance of oil ; it does not, however, tual » but "Jay
combine fo ftrongly with the oil as to refift feparation in the othcr matters.
fame manner, and is therefore very proper to be conjoined
either with lixiviate falts or lime,, as it renders a lefs quantity
of either fufficient, and indeed contributes to the feparation
of the oil from them.

Magnefia alba or the alkaline earth which is the bafis of the Magnefia and
fai catharticus, and the Angular earth vvKv. is the bafis 0falu™flereJeaed-
alum, both have an edulcorating power J fetid oils; but,
like lime, have too ftrong an attraction with ihem to be fepa-
'rated fo as to admit of the reduction of the oil from the con:
creted ftate to which they reduce it ; and therefore, as they
are not fuperior in efficacy to lime and chalk, but much dearer

3 or

|0 PURIFICATION OF FISH-OIL.

or more difficult to be obtained, they may be rejected from;

the number of ingredjenis that are proper for the purifying of

oils, with a view to commercial advantages,

Sea-falt ufeful Sea-falt has an antifeptic power on the mixed folid parts of

in mixtures but an;ma]s . but ufed alone, or diifolved in water, it does not
not alone. '

appear to letter) the putrid fetor of oils, but on the contrary

rather increafes it. If, after their commixture with it, they
are fubjecled to heat, it rather depraves than improves the
oils ; but though by its own immediate aclion on them it
conduces fo little to the edulcoration of oils, yet it is a me-
dium for the feparation of water and the alkaline fubftances
requifite to be employed to that end. It is of great utility in
the ecjulcorative procefles : for when alkaline falts or earths
combine with the water neceflary to their action on the oils,
or themfelves form coagulums or corrections with it, a folu-
tion of fait will loofen the bond and diflblve the clofe union ;
fo that the oil being feparated will float on the aqueous fluid,
while the earth, if any be in the mixture, will be precipi-
tated and fink clofe together to the bottom of the containing
veflel.
Muriate of Sal catharticus, glauber fait, nitrum vitriolatum, tartar, and

ttjj ™jjate Other neutral falts, though they counteraa putrefaftion in the
potafh, &c. of mixed or folid parts of animals, feem to have little, effect on
little value- 0j|s w;tn refpecl to their edulcoration, and cannot therefore
be ranked amongft the fubftances proper to be ufed for that
purpofe.
Oxide of lead is Lead reduced to the ftate of a calx, either in the form of
very powerful, mjmum or litharge, has a ftrong edulcorative power on fetid
oils, and is indeed applied to that end, wi^h refpect to one
kind of vegetable oil, for a very bad purpofe, confidering its
malignant qualities on the human body.

In the cafe of train-oiJ, which will fcarcely ever be con-
fidered among the efculent kinds in this country, the fame
objection againft its ufe would not lie ; and employed either
with or without heat, it is a powerful abforbent both of the
putrid and empyreumatic parts that occafion the foetor.
but was reje&ed As however there may be fome prejudice againil its ufe,
from prejudice. even \n any way, and as it is not abfolutely neceflary, I have
not given it a place among the ingredients of the procefles I
recommend.

The

PURIFICATION OF FISH-OIL. \\

The ochrous earth of iron, commonly called red ochre, Jias Red ochre may-
an abforbing power on the putrid parts of oil, but combines turc>
fo ftrongly, that the feparation is tedious even with the addi-
tion of brine ; if, neverthelefs, it is added when chalk and
lime have been fome time commixed with the oil, as in pro-
cefs the firft, it will promote the edulcorative intention, and
will fubfide along with them ; and, as it has fome advantage
without increafing the expence, unlefs in the mod incon-
fiderable degree, its ufe may be expediently admitted in that
procefs.

EfTentiat and ethereal oils are applicable to the prevention Volatile oils in.
of putrefaction in the mixed and folid parts of vegetables, softly"* *"
but are not fo to the edulcoration of fetid oils ; and if they had
the delired effect, they would not, on account of their price,
anfwer the commercial end, unlefs the due effect was pro-
duced by adding them to the oils in a very fmall quantity.

The fame holds good of fpirits of wine as of eflential and So likewife are
ethereal oils, both with refpea to their efficacy and the ex-alcoholandether*
pence.

Water has an edulcorative action on fetid oils, by carrying Water by agita-
off the moil putrid parts of the gelatinous fluid or bile, in **"» improves
which, as was above explained, the principal fcetor refides, f00n pUtrefy
if the quantity added be large, and an intimate commixture aSain»
be made of them by ftirring them together for a confider-
able time : this only partially removing thofe heterogeneous
putrefcent fubftances, the remaining part foon acquires the
fame ftate and the oil again grows fetid, though not to the
Tame degree as before.

Water is, however, a neceffary medium for the action of It is necefiary
falts and the feparation of alkaline earths and calces of metals, ^cheefl^mPoun*
when they are employed for the edulcoration of oils, as will
appear from a confi deration of my proceues.

Air edulcorates oil by carrying off the mofl putrid parts, Air is ftill lefs
which are neceffarily extremely volatile. It may be made to efte<aual*
act on them either by fimple expofure of them to it with a
Jarge extent of furface, or by forcing it through them by means
of ventilators as has been practifed by fome dealers ; but is
now, I believe, neglected on account of their finding the im-
provement of oils by it not adequate to the trouble, as the
gelatinous matter and bile, not reduced to a certain degree of
putrefaction, being left behind, putrefy again to nearly the
fame degree as before.

It

12

FURIFICATION OF FISH-OIL,

Refumption.
Lime, chalk,
fea-falt, and
alkali, are the
materials for
purifying oils.

It appears from thefe feveral obfervations, that the cheapeffc
ingredients which Can be ufed for the edulcoration of trains
oils, are lime and chalk, which may, with the addition of a
proper quantity of folution of fea-falt or brine, be made to
procure a feparation of them from the oils, according to pro-?
cefs the firft, fo as to anfwer for fome purpofes; that the
lixiviate Gilt is the mofl powerful purifier of oils, and, with
the afljftarice of chalk and brine, will, without; heat, accords
ing to procefs the fecond, effect a very confiderable degree of
edulcoration ; and that lixiviate fait ufed with heat, with the
addition of lime and chalk, to fave a part of the quantity
which would otherwife be neceffary, and of brine to procure
a quick feparation, will perform an edulcoration fufficient for
all commercial purpofes, according to procefs the third ; but
that calcined lead and the ochrous earth of iron may, perhaps,
be applied in fome cafes with acjvant^ge, where the oil is not
defigned for efculent ufe,

proeefs i.
Moderate puri-
fication.
Chalk and
flacked lime
agitated with
oil j fait water
added ; repofe }
deanution.

PROCESS THE FIRST.

For purifying Fijh-oil in a moderate Degree, and at a very little
Expence,

TAKE an ounce of chalk in powder, and half an ounce of
lime flacked by expofure to the air; put them into a gallon of
{linking oil, and, having mixed them well together by flirring^
add half a pint of water, and mix that alfo with them by the
fame means. When they have flood an hour or two, repeat
the flirring, and continue the fame treatment at convenient
intervals for two or three days j after which, fuperadd a pint
and a half of water, in which an ounce of fait is dUTolved,
and mix them as the other ingredients, repeating the flirring,
as before, for a day or two, l<et the whole then fland at reft,
and the water will fink below the oil, and the chalk fubfida
in it to the bottom of the veflel. The oil will become clear,
be of a lighter colour, and have coniiderably lefs fmcll, but
will not be purified in a manner equal to what is effected by
the other proceflfes below given ; though, as this is done with
the expence of only, one ounce of fait, it may be practifed.
advantageoufly for many purpofes, efpecially as a preparation
for the next method, the operation of which will be thereby
facilitated.

PROCESS

UNIFICATION Of FISH-OU* |*|

PROCESS Tti£ SECOND.

ib purify, to a great Degree, Fijh+oil without Heat.

TAKE a gallon of crude flinking oil, or rather fuch as has Procefs a.
teen prepared as above mentioned, and add to it an ounce °f^J!f J^"^
powdered chalk j ftir them well together feveral times, as inheat. Agitate
the preceding procefs ; and after they have been mixed fome^th.cha,^! ad,i
hours or a whole day, add an ounce of pearl-alhes, diitolvedpeari.afliesi
in four ounces of water, and repeat the ftirring as before. falt water *•
After they have been fo treated for fome hours, put in a pint u^.'
of water, in which two ounces of fait are diflfolved, and pro*
ceed as before ; the oil and brine will feparate on flanding
fome days, and the oil will be greatly improved both in frnell
and colour. Where a greater purity is required, the quantity s
of pearl-aflies muft be increafep!, and the time before the ad-
dition of the fait and water prolonged.

If the fame operation is repeated feveral times, diminiming Repetition of
each time the quantity of ingredients one half, the oil may be1 e proce s*
brought to a very light colour, and rendered equally fweet in
{mell with the common fpermaceti oil.

By this procefs the cod-oil may be made to burn; and,
when it is fo putrid as not to be fit for any ufe,. either alone or
mixed, it may be fo corrected by the firft part of the procefs,
as to be equal to that commonly fold : but where this procefs
is practifed in the cafe of fuch putrid oil, ufe half an ounce of
ehalk and half an ounce of lime. «

PROCESS THE THIRD.

To purify Fijh-bil with the Affiflance of Heat, where the greatefi
Purity is required, and particularly for the Woollen Manufacture.

TAKE a gallon ot crude flinking oil, and mix it with aProcefs j.
quarter of an ounce of powdered1 chalk, a quarter of an ouncefi^*teft P"rJ*
of lime, flacked in the air, and half a pint of water ; ftir themwith chalk and
together ; and when they have flood fome hours, add a pintI;"je J a<Jd water
of water and two ounces of peari-aihes, and place them overand fimmer it
a fire that will juft keep them fimmering, till the oil appearsjver a fires aid
of a light amber colour, and has loft, all frnell except a hot, and boil . repofe:
greafy, foap*like fcent. Then fuperadd half a pint of water decantation.

in

J4 PURIFICATION OF FISH-OIL*

in which an ounce of fait has been diflblved ; and having
boiled them half an hour, pour them into a proper vefTel, and
let them (land till the feparation of the oil, water, and lime
be made, as in the preceding procefs* Where this operation
is performed to prepare oil for the woollen manufacture, the
fait may be omitted ; but the feparation o( the lime from the
dil will be flower, and a longer boiling will be neceffary*

If the oil be required yet more pure, treat it, after it is fe-
parated from the water, &c. according to the fecond procefs,
with an ounce of chalk, a quarter of an ounce of pearl-afhes,
and half an ounce of fait*

Obfervations on Procefs the Firji.

Ob&t7*ti<ms» This procefs may be performed on any kind of fifli or fea-

oil that is putrid and (linking, and will improve it in fmell,
and generally render the colour lighter, if previoufly dark and
brown : it will alfo conduce to render thefe ails fitter for burn-
ing, which are, in their crude ftate, faulty in that point ; but
it will not meliorate them to the full degree they admit of even
Without heat, and ftlould therefore be praclifed when only a
moderate improvement is required.

The dregs may Secondly, When the oil is taken off from the dregs and

be a?ed. brine, the dregs which fwim on the brine (hould be taken off

it alfo, and put into another vefTel of a deep form ; and oil
landing, particularly if frefh water be added and ftirred with
them, nearly the whole remaining part of the oil will feparate
from the foulnefs ; or, to fave this trouble, the dregs, when
taken off, may be put to any future quantity of oil that is to
be edulcorated by this method, which will anfwer the fame

, purpofe.

Objervdtiom on Procefs the Third.

Procefs 3 is beft Firft. — This is moft advantageoufly perfof med on traifi-oiJ,
Jer train-oil. ca]|eci vicious whale-oil ; and the more putrid and foul it may-
be, the greater will be the proportional improvement, efpe.
dally if there be no mixture of the other kinds of rifh-oils,
particularly the feal, which do not admit of being edulcorated
perfectly by means of heat, but require other methods : but
when the vicious oil is pure from admixture of others, how-
ever (linking it may be> the bad fmell will be removed by this
procefs duly executed, and the brown colour changed to a

Very

PURIFICATION OF FISH-OIL. }J

very light amber ; and thefe qualities will be much more per-
manent in this than in any crude oil, as it will not, from the
degree of purity to which it is brought, be fubject to putrefy
again under a great length of time, whether it be kept open
or in clofe ve(fels.

The oil in this (late will burn away without leaving the leaf! It will then bur*
remains of foulnefs in the lamp : and, being rendered more clcar» *c%
fluid than before, will go further, when ufed in the woollen
manufacture, than any other kind, and will be much more
eafily fcoured from the wool.

If neverthelefs there be any branches of the woollen manu- Kitchen-fluff
facture which require the ufe of a more thick and unctuous JJ^n , J^ .,
oil, this may be rendered fo by the addition of a proper quan- is wanted.
tity of tallow or fat, of which a certain proportion will per-
fectly incorporate with the oil, the fluidity and transparency
being ftill preferred, as well as all the other qualities that "
render it fuitable to the intended purpofe. This may be rnoffc
beneficially done by adding a proper quantity of the refufe
greafe of families, commonly called kltchen-jluff, which being
put to the oil, when moderately heated, will immediately dif-
folve in it, and let fall alfo its impurities or foulnefs to the
bottom of the veflel, and render the purified admixture a con-
siderable faving to the manufacturers.

Secondly. The different qualities and difpofitions of dif- Tn#e quantities
ferent parcels of vicious oil with refpect toed ulceration, render mJ^S^riSS
various proportions neceflary of the ingredients to be ufed.
The quantities Hated in the above procefs are the leaft which
will effect the end in general, and frequently greater will be
required; but this may always be firft tried ; and if it be found,
aflcr fix or eight hours fimmering of the mixture, that no gra-
dual improvement is making in the fmell and colour, but that
the oil continues the fame in thofe particulars, and remains
alfo mixed with the chalk and lime, and in a thick turbid (rate,
a fourth or third part of the firft quantity of pearl-afhes mould
be added, and the fimmering continued till the oil be perfect.
As the quantity of the water is leflened by the evaporation, it
is neceffary to make frefh additions from time to time, that
there may be always nearly the original proportion.

Thirdly. If it be inconvenient to give the whole time of and the boiling
boiling at once, the fire may be fuffered to go out and be re* Ps!.forme(1.*t
Kindled at any diltance ot time ; an i jr, m fuch cafe, a imall

proportion

id

PURIFICATION OP FISH-OIL,

proportion of pearl-afhes diflblved in water be added, and tke
mixture feveral times flirred betwixt the times of boiling, it
will facilitate the operation. The time of boiling may be alfo
much fhortened, if the chalk, lime, and pearl-afhes, be added
for fome days before, and the mixture freqently ftirred.

PROCESS THE FOURTH.

Which may be praclifed alone, injlead of Proeefs the Firji, as it
will edulcorate and purify Fijh-oil to a considerable Degree, Jb
as to anfwer moft Purpofes, and for Proeefs the Third, zvheii
the whole is performed.

Proeefs 4.
Purification by
Eme water.

TAKE a gallon of crude {Uniting oil, and put to it a pint
of water poured off from two ounces of lime flacked in the
air ; let them ftand together, and ftir them up feveral times
for the firil twenty-four hours ; then let them ftand a day, and
the lime* water will fink below the oil, which rauft be carefully
feparated from them. Take this oil, if not fuffieiently puri-
fied for your purpofe, and treat it as directed in Proeefs the
Third, diminifhing the quantity of pearl-afhes to one ounce,
and omitting the lime and chalk.

ROBERT DOSSIE. *

feCula not
precipitable
Tty water.

Ill

An Effay on the Fecula of Green Plants. By Profejbr Proust,

(Concluded from Page 278.Vol. IV.;

1 BELIEVE Parmentier was the firft who doubted, and it
was hot unreafonable in his time, whether the tincture of fe-
cula in alcohol was refinous, becaufe it was not precipitated
by water. But when we confider that water can never de-
tach it from the gluten, that alcohol, oils and greafe have ex-
clufively that property, and laftly, that this fubftance, when
feparated from the alcohol and left to itfelf, is a fat body, te*

* The dregs, remaining after the fundry procefles above men-
tioned, will form an excellent manure ; as has been fince noticed in
Dr. Hunter's Georgical EfTay*.

nacious

ON THE FECULA OF 6UEEtt PLANTS. J7

Parlous and ihfoluble in water; it mutt be acknowledged that •
there is no other product in vegetables to which it approaches
fo nearly. But we fhall find, that, in order to give it this cha-
racter more perfectly, it is only neceffary to add to it a little
oxigen.

The oxigenated muriatic acid, in a few days, bleaches and But rendered
. , , „ . . . ... , .. , more completely

hardens the green retm ; it then becomes ropy, like boiled refinous by ox-

turpentine and its colour is very diffufible in water; but if the igcnatioa.
green part of the fecula belonged to the coloured juices, con-
tained in dying ingredients, oxigen would not convert it into
a refin. At prefent, when experience has taught us not to
fix fuch ftrict limits to vegetable produces as heretofore, be-
caufe we fo often find them united by intermediate qualities,
we (hall not be furprifed to fee that a refin, at its maximum of
divifibility, can mix with water. Do we not find that cam-
phor, effential oils, both animal and vegetable, farcocolle, &c.
are completely diflblved by water ? Yet we do not from that
circumftance exclude fuch products from the claffification
which analyfis affigns to them.

The green fecula acquire, by the action of oxigenated mil- When it turn*
riatic acid, that tawny brown colour which indicates the de-
cay of the leaves in winter, and their aqueous difTufion be-
comes abundantly turbid. On the whole, then, we may infer,
that though the colouring matter of the fecula cannot relift the
action of water, when extracted by alcohol, it is neverthelefs,
in all its other qualities, a fubftance truly refinous; and though
this product, which is one of the moft curious of the vegetable
kingdom, becaufe it adorns it by its various combinations, has
not been admitted in the fyftem of chemical knowledge, yet the
chemifts who have been the moft occupied with it, fuch as
Rouelle, Danel, Sage, Parmentier, &c. have not thought it
lefs worthy of their inveftigations.

This refin, when diffolved in potafli, quits it to unite with This refin quiti
filk, which it tinges of a clear green, but too fugitive to be- JJ^SJSr,
come ufeful ; notwithftanding which it refills the action of with annrfcl
verjuice ; but its attraction for gluten in preference to the ve- ™attcr llkc *
getable fibre, is conformable to eftabliflied principles; for, in
general, colouring bodies attach themfelves to animalifed fub-
ftances, rather than to the fibres of flax, hemp, or cotton.
There is then fomething in the fecula analogous to wool, to
filk, &c. It is the gluten.

Vol. V.— May. C V. Let

Jg ON THK FECULA OF GREEN PLANTS.

V, Let us now examine the fecula by tefts more adapted t*
difclofe die new characters of animalifation.

The fecula pu- j£ ,*n fumraer, the fecula, either boiled or raw, be kept

animal body. underwater, in lefs than twenty -four hours it yields a dif-
agreeable fmell, and foon exhales an excrementous fetor which
continually increafes, and, to which it might be dangerous to
be long expofed. The infectious miafma anting from it, in-
ftantly difcolours metallic writings ; and its liquor, which may
be compared to a cadaverous fanies, alfo rapidly blackens
plates of filv.er.

Steeping of flax. It is, without doubt, from the corruption of this principle,
rather than from any other caufe, that the pernicious exhala-
tions from hemp and flax, while fleeping, arife. Running
waters, which are equally proper to feparate the flax as ftand-
ing ones, quickly carry off their extractive juices; there can
only remain the fecula intangled in the green fibres which is
fufceptible of being deftroyed by fleeping.

The liquor, which at the end of a year, remains above the
rotten fecula, contains fulphurated hidrogen, carbonate of
ammonia, and gluten diflblved by the intervention of the latter
principle.

The liquid very This liquor has alfo this peculiarity, that it prefer ves its

cor{atnately fter" ]ftercoral fmdl after lonS boiling. The produft of its diflilla-
tion contains carbonate of ammonia, combined with a prin-
ciple of infection, which does not blacken metallic folutions,
and with the nature of which I am not at all acquainted* —
Acids, by precipitating the fecula and faturating the ammonia,
do not weaken it ; this has, for a long time, induced me to

The infe&ion think, that though the effluvia from a mats of animal putrefac-

trefyi'nz bodies. ^on ma^ ^erve as a vemc*e to tne phofphorus and fulphur con-
tained in it, yet thefe combuflibles are not alone, the caufe of
the infection. For there is a great difference, for example,
between the fmell of rotten fifh or flefli, of corrupted fecula,
of ftinking cheefe, and thofe of phofphorated and fulphurated
hidrogen.

On Putrefaction.

What, then, is putrefaction ? A change of which we have
very few clear ideas.
Putrefaction is When fecula, curd, flefh, or any organic matters in general,
not destruction, ^yQ pafl*e(j through a certain period of this change, which we

are

Ott ftfE FECULA OF GREEN PLANTS. j£

Are accuftomed to call putrefaction, all at once they flop in a- '
ftate of permanence, in which, unknown combinations feem
to fix, and as it were to fait them, to embalm them, fo as to
infure their duration in this new ftate and to fecure them from
all fubfequent deftruction.

When, for example, the curd, the fecula, the gluten, or but a permanent
the flefh, after having paused through all the changes of an in- ftate*
fection, which is often deadly, and thofe derangements of co-
lour and of form which disfigure them, have at laft arrived,
the one to a cheely ftate ; the vegetables, the dung-hills to
mould, turf, or poudrette ; — flefti itfelf has not been annihi-
lated after an ichorous ftagnation of fifteen years : all ftop at
this point, without being able to pafs the limit, without ever
attaining, at leaft under our eyes, that final diflblution which
muft terminate their exiftence, or reduce them to a mere
earthy matter, inert non ab jimile?n cineribust to ufe the ex-
preflion of Stahl, in ftiort, to a ftate in which no trace of the
radical of their organization can be difcovered.

Putrefaction of this kind in ftri&nefs takes place no where. Complete de-
No fooner do we perceive the derangement of the organiza-. ^J. lv.e P*tr€-
tion of an animal or vegetable matter, lividity, infection, where feen,
but we conclude that this procefs has commenced ; and with-
out confideration, we confound thefe appearances, which be-
long to a fpecies of fermentation, little known, with the ef-
fects of that which alone is the true putrefaction, if its end
agrees with the notions we form of if ; if it be truly an ope-
ration determined by nature to analyfe and refolve into their
laft principles, thofe fubftances which are fubmitted to it.

Hence we may conclude, that ab folate putrefaction is a
thing we are totally unacquainted with. But let us return to
the fecula ; it is time to attend to that which is in fuch a ftate
of divifion as to pafs the filtre.

VII. We will take as an example, the filtered j uice of cab- Fecula from cab-
bage, one of thofe plants which yields it moft abundantly. kaSe Ju^e>
And, at the fame time, the better to demonftrate the differ- albumen.
ence between this fecond fecula and albumen, we will fubmit
the latter to the fame proofs. The white of an egg beat up
with a pound of water, and filtered, will furnifh the teft li-
quor we want.

lft. Into water heated to 50 degrees, immerfe two matrafles, It feparates fro»
one with the filtered juice, the other with albumen. In an ^r b> kfs
C 2 inftant

£0 ON THE FECULA OF GREEN PLANTS.

inftant thejuice will be clouded with cheefe-like flocks which
fall to the bottom ; but at this temperature, the albumen does
not experience the flighted change.

Fee ula, though 2d. Place on a furnace two matrafles, the one with juice

fails by heat! mixed with twenty parts of water, and the other with albu*
men. The fecula, however diluted it may be, will never-
thelefs be entirely feparated by the heat ; thus clearly proving
its infolubility. With refpect to the water of the albumen, as
it heats, it opalifes, without loiing its tranfparency ; it boils,
and becomes contracted, but does not depofit flocks, or any
thing refembling fecula. And, if at laft the evaporation be
com pleated in an open veflel, it ends by leaving only a coat
of white egg. Darcet has already (hewed that albumen dif-
perfed in a great quantity of waiter, is no longer feparable by
heat. Albumen is a foluble mucilage, fecula is not; and the
temperature which coagulates the latter produces no change
on the ftateof thefirft.

Fecula conti- 3d. The water of albumen remains feveral days unaltered ;

nua y epara . ^e jujce 0f plants, on the contrary, is in a continual ftate of
change which never ceafes to difturb its tranfparency. Filter
the juice, it becomes turbid; repeat the filtering, it again be-
comes clouded ; in fliort it continually depofits white fecula.

Albumen a&s 4th. Albumen changes the juice of violets green, and re-

on tefts like an ftores reddened turnlole to blue.

alkali : fecula , . „ , _ . k . . . r , r

not. J he white tecula, walned, does not produce either or thele

changes. And how fhould it? The juices of cabbage, hem-
lock and many others redden turnfole. Betides the property
of changing it to green is not polTefled by the albumen itfelf :
it is known to be owing to a mixture of alcali.
.They differ m 5th. Alcohol feparates light, tranfparent, glary flocks from

alcohol- WU *^e vvater °f albumen, which retain, on the filtre, the ap-
pearance of boiled white of eg£. The juice of plants only
yields to alcohol a whitifli opake powder, which quickly falls
to the bottom of the veflel.

withacloV 6i^' All the acids, hidro-fulphurated water, and ammonia

precipitate the fecula diflblved in the juices ; but thefe re-agents
operate no change on the water of albumen.

*»th ox.mur. The oxigenated muriatic acid precipitates and oxidates" the

■*** » white fecula ; the fame acid firft oxidates and then precipitates

the albumen.

7th, Cryflallized

ON THE KECUL1 OF GREEN PLANTS.- 21

7th. Cryftallized carbonate of potato, magnefia, fea-falt, and with com-
n „ ^i n ,i • i~ pound falts.

muriate of potato, fal-ammonia, faltpetre, &c. thrown into r

a filtered juice, caufe the feeula, which by its nature is but

little foluble, to precipitate in proportion as they diffolve.

The water of the albumen is not difturbed by any of thefe falts.

Confluences.

The white feeula depofited fpontaneoufly, or by alcohol, Feeula infoluble
• i r i .-» • • r i i i • t,, it ■ ,l in water; albu-

acids, falts, &c. is infoluble in water. The albumen is the re- men fo]uble#

verfe : the acids which precipitate the feeula, do not alter the

folution of albumen.

No fait is capable of depriving the albumen of water ; but
with the feeula it is different; its affinity for water is fo weak
that there is none which does not deftroy it; and, consequently
precipitate it.

The white of egg dried and afterwards foftened is reftored, Other ftriking
in bulk, in opacity, in whitenefs to boiled albumen. Not fo differences,
the white feeula ; it becomes of a deep brown. Nay the
greateft number are entirely blackened in drying, fuch asthofe
of cabbage, creffes, folanum lico perficum , &c. and if they are
foftened in water, they will never affume the appearances
which are known in white of egg. In toort, this feeula is
nothing but a part of the gluten which forms the bafis of the
green feeula. If, for example, the feeula of white cabbage, Green and white
feparated by the filtre, be compared with that which is ob-fecu!a*
tained from its juice by heal, and both he deprived of their
colouring parts, the final left difference will not be difcovered.
But, above all, the white feeula is the moft eahly difiblved,
becaufe it is not, like that which is green, in a ftate of com-
bination which oppofes it. All plants contain a portion of
gluten, which, not having been vivified by the light, remains
without colour.

The cabbage, the endive, the (efcarolle) and the plants
blanched by the art of the gardener, alfo yield white feeula,
but in much lefs quantity than when they are permitted to re-
main green. The ftalk of the cabbage and that of hemlock
afford pale feeula in comparifon with that obtained from their'
leaves. But in general it is not neceflary that vegetables fliould
fliow much colour outwardly to indicate their pofTeffing much

gluten.

2£ ©S THE FECULA OF GREEN PLANTS.

Separation hf gluten. The fmall houleleek, as we (hall' fee prefently, yields

exclufive cha- an abundant fecula of a deep colour, and particularly rich in

rafter of albu- wax.

VI II. But it will be faid, that the albumen being the only
product in which the property of coagulating by heat has been
noticed, it would appear natural to conclude that, &c. But
the milk of almonds alfo feparates by heat, alcohol, acids, &c\
Thisis a fad which has been always known in pharmacy, and
neverthelefs a conclufion has never been formed from this
flender appearance that emulfions contained white of egg, be-
caufe even if the characters of animalifation had been per-
ceived in the principles of the emuliions, they ought likewife
to have exhibited other ftriking marks of refemblance before
they could have been coniidered as albuminous *.

The characters It is alfo in this point of view that the gluten of fecula mull

of fecula and foe regarded, becaufe it is neither tenacious, nor elaftic, nor

gluten are not 1,11,

the fame fermentable, like that of cheele f. In announcing it to che-

throughout, &c. m]fts as a product analogous to that from wheat, Rouelle only
brought forward part of the chara&eis which conftitute the
agreement, thofe alone which belong to the nature of the com-
ponent parts, becaufe the external marks of refemblance do
not exit! ; for the fame reafon, my object, in defending the
labours of this great matter, is much more to retain in the ca-
talogue of his difcoveries that of an animalifed matter found
more immediately in the leaves, than of gluten properly fo
called, becaufe this in fa6t, is the difcovery which the author
of the " Syftem" has rendered doubtful in his work. Break

* Rouelle had a much better foundation than he was aware of,
for comparing the green juice of plants to an emulfion. Thecheefe
feparated from the milk of almonds, by fome one of thefe means,
being warned and dried, yields an oil by expreflion, and afterwards
all the produces of cafeum, by diftillation. This, without doubt,
is the reafon why almonds and all forts of nuts, afford fo great a
quantity of nitrogen, with nitric acid.

The thin milk of almonds contains gum, a little extractive mat-
ter, and fugar, which is either that of the cane, or that which I
difcovered in the grape, and which I fhall defcribe when treating
of fermentation.

t The gluten of wheat is fufceptible of a fermentation which is
peculiar to it. The gafes difengaged are carbonic acid and tolerably
pure hidrogcn in abundance, I lhall hereafter refume this fubjecl:.

the

ON THE FECULA OF GREEN PLANTS. 23

the aggregation of animalifed matters, take away the forms of
filk, horn, wool, feather, &c. and it is clear that then being
confidered only as to their conftitnent parts, they would be al-
bumen, gluten, fibre, and all that can be ftated, becaufeif the
conftituent parts are, in all refpecls, the fame, (which even
now has not hitherto been examined, and which neverthelefs
is the only proper means of diftinguifhing them from each
other,) nothing would remain but to afcertain the proportions
in which nature has combined them, in order to give them
their refpective properties or being.

But, it may be added, that if the albumen be not feparated Whether fecula
from the juices with characters as diftina as may be wifhed, be aIbamen*
this muft be afcribed to the extracl, the falts, and the acids
which are conftantly united with it, and which cannot but dif-
guife it a little ; it is particularly in the warnings of flour that
it muft be fought, to be obtained in fuch a ftate of purity as
to put its nature paft all doubt. Let us fee then what the
warnings of flour will afford.

IX. The water of flour like a recently filtered juice, is in a Water of flour
ftate of change continually increafing, and which does not refenMes a fil-
ceafe until the acid arifing from the fermentation of the fac-
charine principle has completed the precipitation of the gluten.

All the acids, all the falts which have been applied to the
juices operate in a fimilar manner upon the wafhings of flour;
alcohol does the fame, but not vinegar, becaufe it diflblves the The gluten fe-
gluten. In a word, it is not by coagulating the gluten that parated by acids,
acids feparate it from juices and the water of meal, becaufe
ammonia and falts do the fame, but rather by attracting the
folvent of a fubflance which appears to borrow its folubility
from a pure and fimple divifion, but not from an affinity fimi-
lar to that which unites gums, fugar, or albumen to water.

The water from flour expofed to a heat of fifty degrees, and by moderate
parts with its gluten like the juice of plants. Neither can fo-heat'
lubility be imparted to the gluten by diluting it with a large
quantity of water. It is precipitated by the flighteft impref-
iion of heat.

I have collected to the quantity of an ounce of gluten, fe-
parated by heat from fuch wafhings, to be kept in its own
moifture; it fermented and produced vinegar and ammonia.
At prefent, after two years, it is a dark mafs, cellular, odo-
rous and favoury, like the eheefe from glutei.

To

524 ON THE FECULA OF GREEN PLANTS.

Albumen has To conclude; albumen has not yet been difcovered in vc-

«* been dif- getables. Though it is not to be thence inferred, that it is

covered in . .

vegetables, impoflible it fliould be formed there as" well as in animals.

The time in which we live, more fertile than ever in obfer-
vations, convinces us daily that there are few products, either
of one kingdom or the other, which can be truly confulered
as exclufive. Neverthelefs it muft be admitted that in en-
deavouring to eftablifh the exiftence of albumen to the exelu-
fion of the gluten of green plants, the learned author of the
" Syftem" has depended too much on the feeble fupport of a
fimple appearance. It appears to me that, before ftating the
exiftence of the albumen, he ought to have ftrengthened his
firft opinion with facts more conclufive than the (ingle one of
concrefcibility. Let us not however overlook that, in fo vaft
an enterprife as his, it is very difficult for an author to bring
all his materials together with equal precifion.
Remarks on It will be in the fame difpofition that I (hall extend thefe

other objects, conclusions to the other products, placed by Fourcroy, without
fufficient examination, among the glutinous fubftances of ve-
getables.

There exifts, fays he, an obfervatian more exact and more
pofitive than that of Rouelle upon the prefence of this gluti-
nous matter in the vegetable texture which forms linen, paper,
&c. p. 296. vol. vii. It is fufficient to recall this paffage to
the recollection of its author. More details on my part, would
have too much the appearance of cenfure. I think Fourcroy
will fupprefs it in a new edition as well as that relative to the
pafle of mallows. If this pafte be entitled to be placed in the
clafs of the animalifed products of vegetables^ almond pafte,
and thofe of frangepane, eggs, marmalade, &c. are equally
deferving to be fo arranged.
Bird-lime is a With refpect to the bird-lime mentioned in the fame chap-
jtmd of turpen-tc^ .^ y uniVerfally known to be only a kind of turpentine,
an inflammable aromatic refin, foluble in alcohol, formed by
vegetation in the fibrous texlure of the holly-oak, in the fruit
of the elder, perhaps in its bark, and in other plants, but in
no refpect a glutinous fubftance.
Green fccula x Potafh eafily diflblves green fecula, and divides it into

and leaves woody two Parts J one "n'tes lt^ to tne folvent and the other is fe-
xnatter# parated in the form of a green powder which is not affected by

a new quantity of potafh. This powder, being wafhed and

dried.

ON THE FECU1A OF GREEN PLANTS. jjj

dried, yields by diftillation the produ&s of white wood, of
linen, that is to fay, nothing ammoniacal. It is the woody
part which ufually accompanies the fecula in confequence of
the trituration.

This folution has all the characters of an animal folution ; The folution
it exhales ammonia, an odour which is that of a woad vat ; ra^er$#
it blackens tha filver evaporating bafon, and emits, by the
action of acids, an effluvium which darkens the writing of
white metals.

But in this cafe, as in the foap of wool, great part of the But the fecula
fecula experiences a lofs which deranges the nature and pro- cannrot ® re-
portion of its radicals. Acids only feparate a fmall quantity
of the fecula. The remainder acquires an extractive cha-
racter which difpofes it to unite with water. Neither alcohol
nor acids can feparate this new extract from falts. It is of a
fawn colour, and muriate of tin precipitates from it a dulky
lake.

With refpeft to the other, when collected and warned on Properties of the
the filtre, it is worthy of notice that it has not loft the pro. fcp«*ed natter,
perty of hardening by the heat of boiling water.

Alcohol acquires a deeper green from the precipitated
fecula than from that which is frefti. This arifes from the
refin, which not being deftruclible like the gluten, is united
in greater quantity to that which efcapes the deftruclion. As
to its other properties, this fecula, by diftillation, yields
ammoniacal products.

XI. An acid of 18 or 20 degrees difengages azote abund- Adds feparate
antly from green fecula ; a ftronger acid diuolves them with J**J^ ^JJ"J
facility, and feparates a little powder which is the ligneous
fragments of the plant.

However fparingly the nitric acid is ufed, it is but feldom
that cryftallifed oxalic acid can be obtained. It is refolved
into carbonic acid and water.

The folutions of fecula always contain the yellow bitter
principle pi' Welter, fulphuric acid, benzoic acid, oxalate of
lime and fat. If the folution of a fecula containing iron,
fuch as the folanum lycoperiicum, be precipitated with acetite
of lead, a powder compofed of oxalate and phofphate of lead,
and oxide of iron is obtained. On heating it with the blow-
pipe it burns, even the lead is diffipated and nothing remains
but a globule of phofphate of iron.

When

26 0N Tl*E PECULA OF GREEN PLANTS.

When a vegetable product contains? nitrogen, fulphur,
phofphorus, benzoic acid; fat, yellow bitter, iron in abund-
ance, no doubt can remain of its belonging to the clafs of
animalifed fubftances.

Of Wax.

Wax is a vegeta- XII. Wax is the work of vegetation, and not of the bees.
tie matter. l . . , , & '

It is, I think, in deriving nourishment from the gluten which

accompanies it in the duft of the ftamina that they make the
reparation. This duft yields ammonia in abundance, which
has led me to believe that it contains gluten ; and now that I
have di (covered wax in certain fecula, I am of opinion, that
if this duft was treated with nitric acid, wax would be ob-
tained.

It" may be had The fecula of the fm all houfeleek yielded a quantity that

from fecula. furprifed me. This wax is white, dry, brittle and without
fmell ; it cannot be confounded with the febaceous products
obtained from other fecula, fuch as thofe of hemlock and
folanum. MefTrs. Fernandez and Chabaneau examined it to
fatisfy themfelves; they chewed it, and were convinced that
this product was a perfect wax.

The fecula of green cabbage alfo yielded it, but in much
lefs quantity. The wax appears to me to be the varnifh
fpread over the plants by vegetation, doubtlefs to preferve

It covers plants} them from the effecls of wet, which might injure them. It
is this varnifh which divides the rain and the dew into the
filvery pearls upon the leaves of cabbages, poppies and fo
many other plants which afford this agreeable fpeclacle in our
gardens. It is alfo the wax which the curious gardener who
gathers a plum, a fig, or a grape is careful not to rub off
with his fingers.

At Paris, an orange on removing the paper in which it has
been wrapped from its leaving Portugal, will be found covered
with a farinaceous coating, which may be taken off with the
blade of a knife, and then brought to a candle and melted
to afcertain its nature.

The fecula of opium alfo contains a fat which from its
firm confiftence, nearly refembles wax, and which has been
known to many opiologifts.

and fi!k» Finally, raw filk is alfo covered with a coating of wax

■which is carried off, with the colour, by alcohol, and is
feparated from that fluid by cooling.

Of

ON THE FECXfLA OF GREEN PLANTS. 27

Offome other fecula left known.
When five or fix pounds of faffron are operated upon at the Fecua from
fame time in order to obtain the volatile oil and extract, a
fine powder is obfervable in the decoction, which renders it
cloudy, precipitates, and may befeparated by {training. This
powder warned affumes in drying the contraction and horn-like
appearance of the green fecula in fummer; it putrefies rapidly
and becomes food for worms if care be not taken. In the
fire this fecula yields all the produces of gluten. With alcalis
and lemon-juice, it tinges filk of very brilliant yellow.; j

1»

Borage.

A plant may contain gluten in two ftates: the one, in the from borage j
fecula ; the other, diffolved in its juice by means of potafh. •■■*•"

Such is the juice of borage; clarified, it is thick and of a
light blue colour ; a few drops of acid feparate from it a cheefy
curd which may be collected on the filtre, and is nothing but
gluten.

Elder. Dwarf Elder.
The berries, in themidftof an highly coloured, very gummy, from elder and
and flight by faccharine juice, contain a fecula as green as that war € cr*
of fpinach when it has been well purified from its red colour.
Alcohol extracts from it a green tincture ; the refidue is a
gluten not at all different from that of fecula.

On crufhing thefe berries their bird-lime (ticks to the fingers ;
it is of the fame confiftence as that from the holly-oak : fub-
mitted to fermentation thefe juices yield a very fmall quantity
of fpirit of a difagreeable fmell. It is fucceeded by an aftonifh-
ing quantity of very good diftilled vinegar.

Buckthorn.
Its juice, which contains a very naufeous bitter extract with from Buck-
gum and a little fugar, is thickened with a greenifh mud/ °rn:
which is feparated from it by heat and fermentatrbn. This
pulp, well wafhed, is of a clear green ; it is gluten mixed
with a fmall quantity of fibre. It affords carbonate of am-
monia, &c.

Vie Rofe.
Its petals yield by trituration a fine lightly coloured fecula, from the rofe.
which affords the fame products as gluten*

Grapes*

28

BORER FOR DRAINING BOGGY LANDS.

Grapes.
ftom grapes. Fecula is found abundantly in them, it is that which makes

the ley of wines ; but to fpeak of this product would be to
anticipate what I have to fay on fermentation. Laflly, gluten
is found in quinces, apples and, without doubt, in other
fruits ; it is found in the acorn, the horfe chefnut, the Spanifli
chefnut, rice, barley, rye, peafe, and beans of all forts. I
fhall return to this fubjeclin treating of the difference between
wheat which has germinated and that which has not under-
gone this operation.

IV.

drain riles up.

Remedy by

boring.

Defcription of a Borer for draining Boggy Land.
^Thomas Eccleston, Esq.*

Chief difficulty A HE greater!: obftacle to the effectual draining of many
of draining bogs, boggy lands, confifts in the earth in the bottoms of the ditches

The newly cut * . , . r . .. .. . A

or drains when newly cut, and more elpecially ir made to any

confiderable depth, rifing from the preflure of the waters
contained in the bog, by which the new-cut drains and ditches
are frequently fo nearly rilled up, as to impede the flowing of
the water they were intended to carry off, and thereby ren-
dering the work comparatively ineffectual.

There are different layers, or ft rata, in mofs or peat lands,
which will not allow the water eafily to filtrate through
them, yet are of fo foft and fpongy a nature as to rife from the
preflure of the water contained in the bog.

It becomes neceflary to give a free vent to the above con-
fined water, effectually to drain fuch lands. This has been
moit fuccefsfully done by the Augre, a model of which I
have herewith prefented to the fociety.

A common augre, or even a pole, will force a paflage,
and give vent to the water for a fliort time ; but owing to the
peat being only prefled fideways, and not cut out, the parts
foon join again, and the paflage of the water of courfe be-
comes completely obftrucled ; but by means of this augre, a
cylindrical column of peat of fix inches diameter will be
clearly cut out and taken thence, and a free paflage maintained
for a very confiderable fpace of time.

* Soc. of Arts. 1801.

The

Method infuf-

iicicnt.

iMJPkOVEMEKT IN THE GVit-LOCtt. ?>£

The firft experiment made, produced a clear augre-hole but tbe Ja»"ge
of the above dimenfions, four yards in depth,, in one hour; durablAole.
and the water, which had been pent up in the bog, rofe
above the level of the bottom of the ditch, from four to fix
inches ; and the bottom of the ditch, which was previoufly
very foft, and had begun to fwell and rife, in a few days
became more firm and folid, and this in fo great a degree,
that when cleared it remained without fwelling or riling in
the leaih It will confiderably reduce the expence of draining
iuch lands, by rendering them fo firm as to caufe the firft end-
drains to ftand.

The mod proper depth to bore, depends on the fituation.
Where the mofs lands lie low, and are in danger of being flooded,
no greater depth than what is abfolutely neceffary for draining
the fur face mould be bored, as, by deep boring, the land may
be funk fo low as to be liable to inundation.

A. Plate II. Fig. 2. The cutter of the borer, which pene- Defcriptlon.
trates the peat. B. The body of the borer, fix inches in
diameter. C. The aperture through which the peat in-
troduced by boring is drawn out. D. A portion of the iron
bar of the borer, to the upper part of which a crofs handle
is to be fixed.

V.

Defcription of an Improvement in the Gun-Lock by which, the
cafual Difcharge of the Piece is prevented. By Mr. John
Wkbb*.

A HAVE taken the liberty offending to the fociety an inven- The inventor*
tion of mine, to prevent the accidents which frequently at- letter*
tend the ufe of fire-arms, and which may be applied to the
gun-locks now in common ufe. It is contrived on fuch a
principle, that when it is on full cock, and the trigger pulled
in the common manner, it returns to the half cock only,
unlefs, at the fame time that the trigger is pulled, the prelfure
of the thumb is applied on a fpring placed upon the butt or
ftock of the gun ; in which cafe it gives fire in the ufual

• Tranfaclions of the Society of Arts, 1802. To the Secretary j
and the Society gave the inventor a bounty of twenty guineas.

manner.

JQ IMPROVEMENT IN THE GXJN-LOCK;

manner. The intent of this invention is to guard againft the"
cafualties which arife when fire-arms are left loaded, or the
misfortunes which frequently happen from twigs of trees or
bufhes catching the trigger when Iportfmen are paffing
through hedges.

I hope it will meet the approbation and encouragement of
the Society, and am,

S I R,

Your humble Servant,

JOHN WEBB

Defcription of Mr. John Webb's Gun-Lock, Plate 1 \ Fig. 1,
2, 3, 4, 5. The letters of the fever al Figures correfpond
together in the general Defcription.

Defcription of A is the cock — B, the hammer — C, the main fpring—
the lock. D, the tumbler— E, the large fear— F, the fmall fear— G

the fear faring — H, the (hank or arm of the large fear — I,
the thank or arm of the fmall fear — K, the thumb-piece — L,
the trigger — M, the lever of the thumb-piece — N, thefpring
■which holds the thumb-piece up, when not prefied upon by
the thumb.

Fig. 1, is an interior view of the lock at full cock.
Fig. 2. — The fame lock at half cock.
Fig. 3. — The lock when down.

Fig. 4. — The lock fixed in the gun-Hock, in order to fhow
the thumb-piece K and the trigger L, with their mode of
adion. When the gun is held cocked in the ufilal manner,
ready to fire, and the trigger L is pulled by the finger, the
thumb, being piefTed at the fame time on the piece K, raifes,
by means of the lever M, moveable on a pin in its centre,
the thank I of the fmall fear, and admits the cock to give
fire as in the common way ; whereas, if only the trigger L
is pulled, the lock flops at the half cock I ; further motion
being prevented by a notch in the fmall fear. A fpring, N,
Screwed to the ftock, returns the thumb-piece to its place,
when the thumb is taken off*.

Fig. 5 (hows, on a larger fcale, the conftruclion of the
tumbler, large and fmall fears, the fear-fpring, and the
manner in which they rife out of the bents of the tumbler.

VI. Defcription

APPARATUS FOR BREAKING UP LOGS OF WOOD. $£

VI.

Defcription and Account of a fimple Apparatus for breaking-up
Logs of Wood by the Explofton of Gunpowder, By Mr.
Richard Knight *.
S I R,

1 HAVE frequently obferved the great difficulty, labour. Remarks on the
and lofs of time experienced in breaking-up logs of wood, KnLht's aaj
particularly for the purpofe of fuel ; fuch as the flumps and paratus.
roots of large trees, which remain after the felling of timber,
many of which, efpecially fuch as confift of the harder and
more knotty kind, as oaks, elms, yews, &c, are frequently
left to rot in the ground, in order to avoid the neceiTary ex-
pence of breaking them to pieces in the common way, which
is generally effected by the axe, and driving a fucceffion of
iron wedges with a fledge hammer ; a laborious and tedious
procefs. Sometimes gunpowder is ufed, by fetting a blaft
in a fimilar way to that in mines or ftone-quarries. This
method, though lefs laborious than the former, is tedious, is
attended with feveral difficulties, and requires confiderable
experience and dexterity, or the plug will be more frequently
blown out than the block rent by the explotion. With a
view, therefore, to obviate thefe difficulties, I have con-
structed an inftrument, a iketch and defcription of which I
now inclofe for your approbation. The fimplicity of its con-
struction and application is fuch as almoft to preclude an idea
of its originality ; but as it has hitherto appeared entirely new
to all my acquaintance, and as I do not know that any thing
of the kind has ever before been prefented to the public, I
am induced to think it may not be unacceptable ; and fhould
it appear to you an object worthy the attention of the Society
of Arts, I (hall be happy in making it public through a
channel fo highly refpe6bble ,* and will, immediately on being
favoured with )Our opinion, tranfmit fo the fociety a com-
plete inftrument with the neceiTary appendages, and a more
minute defcription of its mode of application.

I am, Sir, Your obedient humble Servant,
RICHARD KNIGHT.
Fofter-lane, March 16, 1802.

* Tranfaftions of the Society cf Arts, 1802. The Inventor re-
vived the Silver Medal.

5 7 he

23 AfPAftAtUS FOR BREAKING! VP LOGS OF WOOft*

The following Articles iverefent to the Societj/. See Plate It*
Fig. 1 and 2.

A, the rending or blowing (brew, with a wire B, for the
purpofe of occafionally clearing the touch-hole, previous to
/ the introduction of the quick-match.

C, an auger proper to bore holes, to receive the charge
of the fcrew.

D, a gouge, to make an entrance for the auger.

E, a lever, to wind the fcrew into the wood, with a leather
thong F attached to it, in order to fatten it occafionally to
the fcrew, to prevent its being loft, in cafe it fliould be thrown
out when the block is burft open ; a circumftance which does
not often occur : for in all my experiments, when the wood
has been tolerably found, I have always found the fcrew left
fixed in one fide of the divided mafs.

A roll of twine is to be fteeped in a folution of nitre, for tha
purpofe of a quick match, or train, to difcharge the powder,
by thrufiinga piece thereof down the touch-hole, after taking
out the wire B.
Aceount of the The firft that was made was for J. Lloyd, Efq. of St. Afaph,
inftrument the ].d{Q member for Flint, who, having a great quantity of
timber on his eftate, confiders it a confiderable acquifition ;
and at Overton-Hall, laft fummer, fpoke fo favourably of it,
in my prefence, to Sir Jofeph Banks, that he immediately fent
for his fraith, and requeiied I would give him the neceffary
inftruclions for making one ; but'as I left that part of Derby -
fhire foon after, I had not an opportunity of feeing it finifhed.
Since my return home, I have had feveral made, fimilar to
that which I now prefent to the Society, which are better
finifhed, and have (harper threads than (mith's in general have
an opportunity of giving them.

Letter from Mr. Lloyd on the fame f abject.

DEAR SIR,

t of the AFTER you left us laft autumn, at Sir Jofeph Banks's, his

ufe and applica- fmith, who is a remarkably good workman, beftowed much

tionof the blaft- needlefs time and trouble in making a blafting-fcrew ; for he

1115 finifhed it in the higheft flyle of pohfh, and, I think, made the

thread of the worm too fine, or at leaft finer than was needful.

However, it anfwered moft completely, and very much to

Sir Jofeph's fatisfa&ion, who lamented he had not feen fuch a

contrivance

APPARATUS FOR BREAKING UP LOGS OF WOOD. 3$

Contrivance many years ago, when a relation of his ufed to
&!mufe him (elf with fplitting the roots of trees, &c. in the com*
mon way. I have ufed the blafting-fcrew, for fo I ihall call it,
all the laft and preceding winter, with the greateir. fuccefs>
and have gained many loads of fuel, which otherwife would
have been fufFered to rot, as the expehfe and labour in clearing
the roots in the ordinary Way renders the fuel fo procured too
expensive ; and fince I have had the fcrew, I have obferved
fome hundreds of roots in a rotting ftate in other places, from
the want of knowing that there was fuch a contrivance as the
fcrew. I think you would ferve the public in no fmall degree,
by divifing fome method of making its ufe known to the workL

When I was at Overton, fome pieces of very tough, knotty,
clofe-grained oak were picked from the timber-heap, for the
ufe of the Gregory lead-mine, by Sir Jofeph Banks's direction,
and the fcrew fevered fome pieees four or five feet in length,
and nine or ten in diameter, throwing Ihem fome feet afunder,
to the furprife of the miners, who were affembled on the mine*
bank. Sir Jofeph took the fcrew with him to Revefby-Abbey,
in Lincolnshire, where, I underftand, he had fome large roots,
that had lain by many years as ufelefs ; and I dare fay he wilt ,

give you a good account, and bear tefiimony to the utility of the
invention. We have ufed it without a tingle accident ; but my
neighbour, Lord Kirkwall, having procured one to be made
by that which I had from you, one or his fervants, in his Lord*
(hip's abfence, I prefume, put too much powder into the hole,
and the fcrew was blown as high as a one- pair pf-ftairs window,
and patfed through it into an apartment where a perfon then
happened to be, but without any farther mifchief than the lots
of a pane of glafs. Any one who ufes the inftrument will foon
Jearn what depth of fcrew will be fufficient to fplit any root in,
proportion to its ftrength, taking care that the fcrew has fuf-
ficient hold to refill: the force of the gunpowder, before the root
is cleft. I think much powder may be laved by ufing a cotton
match, impregnated by a folution of faltpetre, or any of the
combuftible matters generally made ufe of in fire-wrorks ; and
by the ufe of the cotton the hole through the fcrew may be
leflened, which will add to the action of the confined powder,
though a ftraw filled with powder, in the manner in which the
miners ufe it, anfwers very well. Should any one be timid in
ufing the fcrew, a chain or rope may eafily be attached to the
fcrew, and that fixed to any log, or fattened to a fiake driven

Vol, V.— May. D into

S4» DALTON ON THE ZERO O* HEAT!

into the ground. If wood is rotten, the fcrew cannot act. I a(Tur£
you, that when I go abroad, I conftantly fee great quantities of
roots in a rotten ftate, about almoft every farm-houfe, which
would not be the cafe if the utility of the inftrument were made
public. I am,

Your much-obliged friend, and humble fervant,
Wijvfair, March 26, 1802. J.LLOYD.

VII.

Letter from Mr. Dal ton, containing Observations Concerning
the Determination of the Zero of Heat, the thermometrical
Gradation, and the Law by which denfe or non-elajlic Fluids
expand jby Heat.

Manchefter, April 20th, 1803.

To Mr. NICHOLSON.
SIR,

Remarks on a IN your laft Number, page 221, a correfpondent has ad-

letter in our lad verted to an hypothefis which I fuggefted in my account of

eernine'the real experiments on the expanfion of elaflic fluids. It was, that

zero of heat. " the repulfive force of each particle [of gas] is exactly pro-

** portional to the whole quantity of heat combined with it,

when fubject to a given preilure. Having previoufly found

that 1000 parts of any elafb'c fluid, at temperature 55°, were

expanded to 1325 at 212°, it followed from the hypothefis,

that the quantity of heat in air, of 55°, is to the quantity in

air of 212&, as -y/1000 : ^1325, or as 10 : 10.9834- : from
which the real zero is deduced at 1573° below the freezing
point of water. I had moreover noted, that for 78-|° (as the
abovementioned writer has juftly corrected it) the expanfior*
of air was 16*7 parts, and for the other 7$j°, only 158. — •
From thefe data, calculating, as he fays, upon my hypothefis,
lie has deduced two other points for the real zero ; namely,
$714°, and 1486° : thefe inconfiftent refults, he thinks, tend
to difcredit, either the hypothefis, or the accuracy of the ex-*
periments. Now he mull give me leave to obferve, that the
two lafl deductions are not derived from my hypothefis, but
from another totally inconfiftent with it ; namely that the?
mercurial thermometer is an accurate meafure of heat. For,,
upon the hypothefis that the real temperature is as the cube-
root

BALTOl* ON THE ZERO OF HEAT. Qj

joot of the aerial fpace, it will be found, that when the mer-
curial thermometer ftands at 133-§Q, a proper equidifFerential
thermometer would ftand at 139° 3. Hence no inconfiflent
refults can be derived from the above data.

Before the merits of the hypothefis in queftion can be de-The mercurial
cided, we mull: have an inftrument to meafure equal incre- ^Twreft '*
xrients of heat. The mercurial thermometer equally divided meafure of fieat*
is not that meafure. De Luc has fhewn that the true mean
heat betwent freezing and boiling, is feveral degrees below
122° per fcale. Even Dr. Crawford, who has manifefted
more defire than any other perfon to find the mercurial ther
mometer an accurate meafure of heat, has concluded from a
variety of experiments, all of which prove that mercury ex*
pands more in the higher than in the lower part of the fcale^
that the thermometer is nearly accurate only. Now it has
been fhewn, that elaftic fluids obferve a general law of ex-
panfion, whether by heat. Or diminifhed preflure. Why
mould not liquids do the fame ? — I expe£t to be able in a E<pe<&itfo#

mort time to demonftrate that water and mercury agree in a* a!i ila,u'<«

, . r . r r c .? Wl11 be found *

one ana the lame law or rate or expanuon from the two obferve the fame

points at which they freeze and boil refpectively : and yet law of expan-
thefe two liquids are apparently the moil difcordant in this *
refpect. It would certainly be a moft extraordinary anomaly,
and inconfiflent with the fimplicity of the other laws of nature,
if mercury alone mould be excepted from a common law by
which all other liquids expand, not uniformly, but itfcreaf-
ingly, with equal increments of heat. The truth is, I be-
lieve, that the fame quantity of heat which raifes the mer-
curial thermoter 2° at the freezing point (of water), wil[
raife it about 3° at the boiling point, A mercurial thermo-
meter graduated according to the hypothefis I have fug-
gefted, that the increments of heat are as the increments of v
the cube roots of the manometrical fpaces, (in which cafe it
no where differs more than 7° from the common equal gra-
duation for 1 80) does, I apprehend, in all cafes, indicate tn£
true mean temperature, when hot and cold waters are mixed
together ; at ieaft, I have not been able as yet to find any de-
viation.

"With refpect to the difcordance, exhibited by Seguin, in Segum's defer * .
the refults of experiments to determine the real zero, it may m,nation °*
arife from an error in the theory, or from errors in thevexpe-

D 2 rimei%

3t> tXAMItfATtON OF THE TEETH.

riments. t am inclined to afcribe it to the latter. The fim-
plicity of the doctrine of heat, maintained by Drs. Irvine and
Crawford, is to me fo ftrikingly apparent, when contrafled
with the now prevailing, but, I think, unfounded diftin&ions
of combined and uncombined, or free caloric, that I fliould be
very unwilling to difcard it; but upon clear proof of its being
incompatible with the phenomena.

I am your obliged friend,

J. D ALT ON".

The bones long
ago analy fed j

bat not the

euimel of the
teeth.

Tlii* Uft is the
author** objeft.

, VIII.

Memoir containing the Phi/fical and Chemical Examination of
the Teeth. By Cit. Josses, of Remits *.

jT\.MONG thofe animal matters which have been analyfed
with the mod attention, the bones may be felecled. For a
long time, they were believed to be formed of earthy fnb-
ftances, the particles of which were connected by a peculiar
gluten : at prefent it is afcerlained, that they are a true faline
concretion, known by the name of phofphate of lime, mixed
with a certain quantity of gelatine. The experiments made
to prove this have been fo often repeated, particularly in the
extraction of phofphorus, and are fo well known, that they
cannot now be called in queftion.

But though there be no longer any doubt as to the ofleous
fubflance, the fame cannot be faid of the covering which
cloaths the furface of the expofed part of the teeth. This
Covering, conftantly confounded in the general clafs of J>ones,
feems never to have undergone a thorough examination, alone,
by an accurate decompotition. All the authors who have
treated of this fubjecl, appearing to have done it too inatten-
tively, have committed errors, which it is effential to correct.
Though it has been fuppofed, that this covering was formed
of materfals analogous to the ofleous part, to which it adheres,
it is neverfhelefs true, that it differs from it etfentially, in its
phyfica! and chemical qualities, and that it poflefles peculiar
properties, as may be eafily (hewn.

The intention of this work is, therefore, to afcertain the
corapofltion of this covering, to (hew its phyiical and che-

# Annales de Chemie, xliii. 2.

mical

EXAMINATION OF THE TEETH. 37

mical chara&ers, and to point out the error of confidering it

as a common offeous body, having no other difference but the

denfity arifing from the compa&nefs of its conftituent parts.

I (hall firft concifely point out the pbyfical characters of the Phyfical charac

enamel of the teeth, and then proceed to the chemical invef-^j°f ^ J^.

ligation. This analyfls rauft more fully elucidate the phyfio-

logical inferences I lhall then offer, to prove that nature has

affigned particular functions to this fubftance, which differs

abfolutely from the bones.

When examined on the fur face of the teeth, the enamel is It appears chryf-
,.,.,,., r 1-1 i r talhzed in its

white, lmooth, pohfned, tranlparent, very brittle, and or fra&ure.

extreme hardnefs : its fracture lliews a very diflinct, regular

chryflallization, formed of an affemblage of fmall brilliant

cryflals, very compact, and inclining to the fliape of needles.

On all the furfaces which it covers, as well as in the interior

of certain teeth where it is found, it is difpofed in radii, a

little oblique and horizontal, alinofl perpendicular to the body

of the bone, forming at the point of contact, with it two

angles, the upper one re-entering and acute, the other infe-

ferior, re-entering and obtufe. This fubftance is found in

this manner, in all animated beings which have teeth.

From this fliort fketch of the phyfical characters of the Its characters
teeth, it will be feen, that it is impoifible to avoid concluding, Qlf^c £££} °
that the enamel is very different from the offeous body to teeth,
which it adheres ; for which reafon I have often propofed to
•niyfelf, to make a fcrupulous examination of it, A favour-
able circumftance offered itfelf, and furnifhed me with an
opportunity of making the experiments I had long intended :
an opportunity which I (hould not eafily have found any
where but at Paris. Before recounting the means I have
employed, I ought to fay that thefe experiments have been
performed in the laboratory of the medical fchool.

The analogy of the work I wifhed to undertake, with the
interefling researches on animal fubflances, which continually
occupy the profeffors of chemiflry of the medical fchool : the
flattering approbation and eagernefs expreffed by profeffor
£)ei/eux, in affi fling me with his advice ; the zeal manifefted
by the pupils of this laboratory, to whom the care of per-
forming the operations is confided : in fhort, a, multitude of
facilities left me no doubt that my hopes would be crowned
with fuccefs.

One

38 EXAMINATION OF THE TEETH.

One of the firft things to be attended to, was to procure
the enamel pure : this operation was not without difficulty as
will be eafily conceived, from the clofe adherence which this
fubftance preferves with the cfleous body, from the time the
germ of the tooth is developed aod ha? paifed through the re-
gular periods of the formation of the enamel, and of ofiifica-
tion. Neverthelefs, a fufficient quantity may be difengage4
from the bony part, by the afiiftance of chemical agents,
which, without producing any efTeft on the animal, act very
readily on the bone ; fuch are the means which will be point-
ed out, and which I have employed tq perform the expe-
riments I am about to defcribe.

Having procured fome human teeth, as well as thofe of
feveral animals, I expofed them to the action of various che-
mical agents.
The enamel j then filed off the enameiied furfaCe of fome teeth, with-

affbrded a very - a T" r i •

(light indication out reaching the oueous part, I cauled the filings relulting

pf gelatine. from this operation to be boiled in water, and I fubmitted the
liquor to the action oftanin. I obtained fo flight a preci-
pitate, that this operation fcarcely mowed the prefence of
gelatine. On the contrary, the ofTeous body, in the fame
proportions, and by the fame procefs, yielded an abundant
precipitate.
Papin^s algefter j expofed whole teeth in water, to a degree of heat fuperior
but not the ena- to tnat of ebulition, by means of Papin's digefler ; the enamel
jnel of teeth. preierved its hardnefs and its figure, but the bony part was,

foftened and became friable.
The enamel does jn'a naked fire, the enamel does not burn like a bone; the
t,one. fmell arifing from the igneous decompofition of an animal

Aibftance, is fcarcely perceptible; it is not converted into
charcoal, but is (lightly browned and decrepitates.
DifVjllation ex- When carefully feparated from the body of the bone, and
tricates fcarcely dIftilled m t t thi fubftanCe (hews only a faint trace of
any thing from . . J

\u animal product ; it does not afford, like the bone, a great

quantity of phlegm, of oil, of corbonate of ammoniac, or of
carbonate hydrogen gas ; and in all its phyfical and chemical
characters, it prefents differences which keep it diftinct from
the offeous body.
It Is foluble in However unfufceptible of change the enamel may appear
•"•*• to be, it is neverthelefs foluble in all the acids, but with re-

markable differences, which depend on their radicals, their
3 concentration,

EXAMINATION OF THE TEETH. 39

concentration, their combined or infenfible caloric, and on
that caloric which, being only interpofed between their con-
stituent particles, is the caufe of their various temperature.
Hence arife varieties in the affinities, wliich change the at-
tractions, and produce different variations in the refults, of
which I fhall have occafion to fpeak.

Having plunged human teeth and thofe of feveral animals Nitric acid adtf
into nitric acid, I obferved that it aded rapidly on the enamel, [f^I^Jd
and flowly on the bone. The firft wasfoon entirely diffolved, flowly on the
and I could only perceive the offeous part, which in its turn* bone*
but in a much longer time, difappeared in an excefs of acid.
When the folution was compleated, I tafted it ; it appeared
to me ftill ftrongly acid, and I found that its tafte differed
from that of nitric acid. To judge of the nature of this li-The nitric folu-
quor, I filtered it, and fubmitted it to fome experiments, tl™J^r** acid.
which mowed that it contained phofphoric acid, difengaged,
without doubt, by the nitric acid.

Teeth digefted with muriatic acid, gave fimilar refults to Muriatic acid.
the former.

But the fame effects were not produced when I employed Sulphuric acid
fulphuric acid : whether concentrated or diluted with water, enamel S and
hot or cold, the effervefcence with the enamel, which I no- more on the
ticed in the other acids, did not take place with this. Itap-^6,
peared at firft to refufe to diffolve this fubftance, but I foon
faw it act on the bony part. In a little time I obferved it
precipitate a whitifh fait, which I knew to be a true fulpjiate.
of lime. This folution alfo preferved its acid tafte, of which
I could not deprive it, notwithstanding the pains I took by
adding frefh teeth. This acidity was owing to the phofphorip
acid which had been difengaged.

The experiments which I have juft 'defcribed with the The enamel fe«
three acids, did not fatisfy me ; they had been performed on P*rat.ed ty fu(-
teeth furnifhed with their enamel. The refults were there-
fore confufed, and it was neceffary to examine them in a
direct manner. I refolved, therefore, to operate upon the
enamel perfectly freed from the offeous part : I endeavoured
to fcparate it with a file, but this method appeared too labo-
rious and too tedious to fumifli me with a fufficient quantity.
I had recourfe to the fulphuric acid : the preference I gave to
it, was pointed out by the laft experiment I have noticed,
^hove* which had left me confiderable portions of the ename^

undiffolved*

40

SXAMINATK5N OF THE TEETH.

Ignition left a
white powder j

inicfiffblved, and perfectly deprived of the ofleous fiibfianc©„
This method (ucceeded beyond my hopes, by weakening the
acid a little, which I made warm to haflen the effect. Thus
I foon procured detached enamel in fuflkient quantity, amply
to fupply the experiments I propofed to make,
Ita appearance. The enamel, feparated in the manner I have defcribed,
was warned in feveral waters before it was ufed, by which
means it was freed from the fulphate of lime, attached to
its furface } it was then dried. Examined then with a magni-.
fying glafs, it (bowed tranfparent parts, the fracture of which,
when broken, prefented very well-defined needle-rihaped cry-*
itals. This enamel was very hard, and perfectly refembled
the fragments which I had broken in fplinters, from the upper
part of a tooth, by ftriking it with a hammer. It only dif-
fered from it in having a whiter appearance fuperficially,
owing to the lime having been made more evident. Some
pieces of this enamel were laid on burning coals j they decree
pitated, and their particles were thrown to a great diftance.

Other fragments, put into a red-hot crucible, having pro-,
duced the fame effect, I pulverized a certain quantity, and
heated it for fome minutes, in another crucible. This pow-,
der firft loll its very white colour, and became a little grey ;
but by continuing the fire, it regained its whitenefs : it then
crumbled eafily between the fingers ; its tafte was alcaline ;
when mixed with water, it was partly diffolved, and the fo-i
lution refembled lime-water.

Another part of this powder triturated with muriate of
ammonia, foon produced the decompofition of this fait, and
difcovered the ammonia ; and laftly, the calcined enamel
was equally foluble in nitric, muriatic, and fulphuric acids,
without any apparent difference. The folutions, examined
by different re-agents, correfponded with folutions of lime.
Though it was evident, from thefe experiments, that lime
was thebafis of the enamel, yet it remained to be difcovered
what it was united to, before calcination.

To obtain proofs on this head, I weighed four grammes of
enamel, prepared, as I have defcribed, with fulphuric acid ;
and, after having wafhed them well with a brufh, to remove
the fmall quantity of fulphate of lime, which was found dur-
ing the feparation of the ofleous part, and precipitated on iu
furface, I pulverized \hem, and proceeded to diftillafiqn in a

cpale^

which was lime.

Di filiation of
this enamel
drove off no
fluid.

EXAMINATION OF THE TEETH. 4|

fcoated glafs retort. The fire was urged fo as to bring the

retort to a red-heat, and after more than an hour, I remarked

in the neck of it, a white fublimation, very light. This was

the only product I obtained, and notwithstanding my care in

keeping up the fire, no fluid was condenfed.

When I judged that the operation was at an end, the ap- a fmall portion

paratus was difengaged, and I haftened to examine the fublr- of whlte fubii-

r , . , , r i ~ . r mate, containing

mate formed in the neck of the retort. J he quantity was lo fome ammonia,

fmall, that I had much trouble in collecting it ; it was dillblved

by nitric acid. I then had reafon to believe that it was lime,

volatized by the action of the fire ; never thelefs, as I had been

itruck with a flight ammoniacal odour, I introduced into the

neck of the retort, a match moiftened with muriatic acid, and

I obferved that fome white vapours were quickly formed.

Therefidue of the diftillation was a whitifh powder, whofe Refidue of lime
tafte was flightly cauftic : it was diflblved by water, and more
readily by acids, and changed tincture of violets to green.
Its folutiou, treated with different re-agents, yielded a true
lime.

On reflecting upon the products obtained during the opera- Whether the
tion, I have given an account of, I thought I obferved a kind enamel be ox-
of analogy with thofe afforded by oxalate of lime. To fa-
tisfy myfelf how far this opinion might be well founded, I
determined to proceed in the analyfis of the enamel, according
to the method pointed out by Fourcroy and Vauqiielin, in the
interefting work published by them on urinary calculi, in
which they (hew that the fpecies of concretion called mural
ftone (pierre murale), is entirely formed of oxalate of lime
and an animal fubftance,

I therefore pulverized fome enamel, and boiled a certain Enamel diflblved
quantity in liquid carbonate of potafh. The liquor was In PoUfl1,
fcarcely boiling, when I perceived a flightly penetrating
odour, nearly refembling that of ammonia. I then introduced
into the neck of the matrafs, a paper match, dipped in con-
centrated nitric acid ; immediately an abundant vapour was Ammoniacal
formed, fuch as is always feen when ammoniacal gas is brought vaP0Ur*
into contact with that difengaged from nitric acid.

When the ammoniacal odour had ceafed, I withdrew the
matrafs, and placed it on a fand-bath. After twenty-four
hours digeftion, I found at the bottom of the matrafs, a white
precipitate^, above which floated a limpid liquor -, it was de-
canted

42 EXAMINATION OF THE TEETH.

canted and filtered, and then poured upon a new quantity of
powdered enamel, and I proceeded as before : at the end of
a fecond digeftion of twenty-four hours, its tafte did not ap-
pear to be any longer alcaline.
Examination of Following the directions of the fame authors, I examined
luSon^tnorder the carbonate °f P0*^ »* which I had digefted the enamel,
to detect oxalic with acetite of lead and barytes ; and obtained a very abun-

fuccef5Vith0Ut dant white PreciPitate- Thefe refults, fimilar to thofe ob^
tained by the above two chemiffc, from mural or oxalite calr
culi, or calculi of oxalate, gave reafon to fuppofe that the
oxalic acid being combined with the lime in the enamel of
the teeth, formed there, alfo, an oxalate of lime. To afcer*
tain this, I tried to decompofe the two precipitates I have
mentioned, but all my endeavours on this point were without
fuccefs *.
Enamel feparat- Fearing that the fulphuric acid, which I had ufed in my
tefter. ° *~ preparatory procefTes, had altered fome of the component
parts of the enamel of the teeth, I procured fome by another
method, and recommenced my operations. Papin's digefter
juflified my hopes ; it afforded me an eafy method of obtain-
ing an abundant quantity, completely difengaged from the
offeous part, and which had not experienced any change from
an acid. The enamel obtained by this new method, and fub-
mitted to the fame experiments, no longer yielded fimilar refults.

* If my fufpicions had been realifcd, it will be perceived, that
the oxalate of lime being thus difcovered completely formed by
nature in living animals, and neceflary in the organifation of the
teeth, the oxalic acid would become a ftriking part of the beau-
tiful theory of the two learned men whom I have cited. This
would have afforded a natural explanation of the calculous oxalates
fn the urinary concretions, as well as of the oxalic acid ibmetimes
obferved in humours, though, their phenomena are always thought
to be unufual, and to arife from morbific affeiiiorjs.

As the formation of the enamel takes place in the firft years of
life, and neceflarily ceafes after the laft dentition, it may eafily be
conceived, that the reflux of the oxalic acid, or the liquid oxalate
lime, by way of urine, which has fo many points of ref'emblance
to offeous fubftances, muft have given rife to the concretion of the
mural calculi, which are more common in youth than in age, as
Fourcroy has well obferved in his works. But after much labour,
I found myfelf compelled to abandon my firft expectations, and to
endeavour, by new inveftigation*, to diicoverlUe truth.

This

MITHOD OF CLEARIKG OBSERVED LUNAR DISTANCES, &C. 43

This fubftance diftilled in a retort, did not now emit any The refidue of
ammoniacal odour, nor did it produce any fluid. The refidue this when dif-

,.„.,, . r i-ii i- tilled was hard

oi the dittillation was of a grey colour, which became white like porcelain

by calcination, and by the intenfe heat of the fire it acquired a"d «femble4

the hardnefs of porcelain ; it no longer had the alcaline tafte, ename|, &?,

it no longer decompofed muriate of ammonia ; it no longer

changed fyrup of violets green, water no longer a6led on it ;

it lhort, the enamel not diftilled and fubmitted to thefe latter

experiments, afforded the fame refults as the refidue of the

diftillation : I again placed fome in digefHon with diluted ful-

phuric acid, for the purpofe of treating it like the offeous fub-

ftances from which phofphoric acid is to be feparated, and I It feemed to be

obtained umilar refults ; that is to fay, acid phofphate of iimephofphatoflirae,

in folution in the liquor, with fulphate of lime, and fragments

of the enamel not decompofed. Thefe are the falts whofe

prefence has been afcertained from examinations by the ufual

methods.

From the great difference of thefe refults obtained in both The enamel
methods of treating the enamel of the* teeth, it will be feen JePafated.^.

° iulpn. acid it

that at firft I was led into an error by the effect of the ful- not pure,
phuric acid, which, in the preliminary preparation left con-
siderable portions of enamel, whofe physical characters caufed
me to believe them unchanged.

I have thought it ufeful for the interefr. of fcience, to make
known thefe furprifing differences, they may be advantageouily
applied in the medical art, and aflift. in explaining the pheno-
mena, as I had occafion to point out elfe where.

IX.

A New Method of Clearing obferved Lunar Dijlances of the Ef-
fects of Parallax and Refraction, for the Purpofe of determining
the Longitude at Sea or Land. By Mr. J. Andrew. Com*
municatcd by the Author.

JLrfET A, B, C, D, PI. 3. Fig. 3. be four given points on Principle of the
any fphere, and fo conflicted that they mall all lie on the fame meth°d de™>»-
imaginary plane; and let the fphere be fuppofed to be cut fo
by this plane, that the lines AB, BC, CD, DA, and BD,
joining the given points, may be all of them right lines, or
chords of great circles which may be fuppofed to have paffed

through

44« . AfETHOD OF CLEARING OBSERVED LUNAR DISTANCES

through thofe points before the cutting of the fphere. Farther,
let the chord AB be parallel to the chord DC, and fince the
four points A, B, C, D, lie in the fection of a fphere, that is,
in the circumference of the fame circle, the chord AD will be
/ equal to the chord BC, and the diagonal BD to the diagonal
AC. For the fame reafon (becaufe ABCD is a quadrilateral
figure infcribed in a circle) the rectangle under the diagonals
BD and AC is equal to the fum of the rectangles under the
oppofue fides AD, BC, and AB, DC ; or, becaufe BD and
AC are equal, as alfo AD and BC, the fquare of BD is equal
to the fquare of BC, together with the rectangle under AB
and DC, ,

Now let the point B reprefent the moon's apparent place,
and D the apparent place of the fun or a ftar, and let the chords
AB and DC be parallel to the horizon ; then is BD the chord
of the arc of the apparent diftance, and AD or BC are the
chords of the arcs of azimuth circles palling through the fun
or a ftar and the moon, intercepted between the parallels of
apparent altitude ; of in other words, AD or BC is the chord
of the difference of altitude. The length of the chord AB is
to that of DC in the ratio of the cofine of the altitude of the
object at B to the cofine of the altitude of the object at D,
and the rectangle under the chords AB and DC will be to the
rectangle under any two affumed chords parallel to AB and
DC, and terminated by the fame azimuth circles which pafs
through the points B and D, as the rectangle under the cofines
of the altitudes of the points B and D is to the rectangle under
the cofines of the altitudes of the two affumed chords. And
fince BD and BC are had by obfervation, the rectangle under
AB and DC is alfo known, being equal to BD2, — i BC*, or
to BD -f BC x BD — BC,

Make b the moon's true place, fituated fome where in the
fame azimuth circle that palled through B, and d the fun, or
flar's true place, fituated in the fame azimuth circle that paffed
through D ; and analagous to A B C D draw the quadrilateral
Figure abed, which will have all the properties of the former,
and ad or be will be the chord of the arc of the difference of
the true altitudes, and b d the chord of the arc of the true
diitance. And it has been already (hewn, that the rectangle
under the cofines of the apparent altitudes is to the rectangle
under the cofines of the true altitudes, as AB x DC is to

OF *HE EFFECtS OF FARALtA* AttD REFRACTIOtf. 45

ab X dc, wherefore the rectangle under ab and dc being found
' and added to the fquare of b c or a d, which is fuppoled to be
known, the Aim will be equal to the fquare of b d, the chord
of the true diftance, which may confequently be determined. Theorems for

If the half chords, or fines of half the arcs be ufed initead clearing the
of the chords of the whole arcs, the true diftance will, from the d,fta"ce of

... parallax and

foregoing principles, be obtained by the following theorems, refraaion.

1 . Sine* /app.dift.g&Qor* \ __ ^, Aliff. app. alt. f|& 0 or *\ ^ Q

2 Cos- M's true a,t- Co-. 0 or *'s true alt. q _

(Jos. ©'s app. alt. Cos. 0 or *.f% app. alt.

3. Sine* (diff- t^ah.^fe 0or*\ + fine, /tniedift. ffiSr Q or*\

If a table of chords, or of natural fines of the 2d power, Tables necefiary.
were conftrucled, the fquare numbers correfponding to certain
given arches, and converfely, the arches correfponding to cer-
tain given fquare numbers, to be employed in the folution of
the above theorems, might be had without farther trouble, by
infpe&ion. A fecond table might alfo be conftrufted fo as to
fit the 2* theorem, and Amplify the calculation for rinding </,
but this happens to have been already done, as Table IX,
with the (hort, additional, corrective Tables X. and XL. in the
3d edition of the requifite tables fully anfvver this purpofe, by
readily furnifhing a logarithm, which added to that of Q gives
the logarithm of q. The nature of thefe tables is explained
near the end of that work.

The method now propofed of folving the problem of the Advantages of
longitude, fo far as a folution depends on finding the true dif-
tance between the moon and the fun, or any given fixed fiar,
has feveral advantages, it \s conceived, over the common me-
thods, as the anfwer will in every poffible cafe, be determi-
nate; the diverfe affections of the fides of the fpherical tri-
angles commonly ufed never ocean* oning in this way any era-
baraffment to the operator, and as there never happens any
change of figns from -J- to — , or from — to -f-, in any part
of the calculation, it is plain the operation mufi always be clear
of ambiguity. It will alfo be found on trial, that the nature
of the numbers employed in this mode of calculation tends
very much to preclude fmall errors, or to render their effects
infenfible. A table of logarithms of natural numbers, a table
of the fquares of chords, and Table IX, with, its corrections

from

4$ METHOD OF CLEARING OBSERVED LUNAR DISTANCES

from the requifite tables, are all the tables neceflary (after
having found the moon and the fun or ftars true altitude) ac-
cording to the new method, for finding the true diftance re-
quired. And as they require to be opened only about feven
times, the whole operation might be eafily performed in about
five minutes ; and if carefully done, the anfwer will not vary
one fccond of a degree from the truth.

EXAMPLES.
JExample*» ] . Given the apparent altitude of the moon's center, 35° 49.57,

and the trtfe altitude 36° 33' 9" ; the apparent altitude of
the fun's center 28° 49' 54", and true altitude 28° 48' 19v,
and the apparent diftance of their centers 95° 31' 2" reqrf
the true diftance.

App. Alt.

Log. Cofiries,

True Alt*

3$ 35 49 57
0 28 49 54

- 9.90S8773 J

- 9.9425241 Q

° /

| 36 33 9

) 28 48 19

2) 7 0 3 19.8514014 2) 7 44 50 -f-

3 30 l! NatTtinG* 0037278 3 52 25 -

| App. dift. 47 45 31 Nat. fine1 5480725 -

Difference 5443447 Log. +

5394990
\ Diff. true alt. 3 52 25 N. S*.* 0045638

| Truedifl. 47 31 40 N. S.1 5440628
2

95 3 20

True diftance*

Log. Cofines*

9.9048840
9.9426341

19.8475181

19.8514014

0.0038833

9.735874Q

= 9.7319907

gd. Example from the Requifite Tables, page 38, 3d Edition, ad Jin.

App. alt. * A 17 , /t True alt. * 11 12 21

— — 3 9 38 Ho. Par. 54 42 - - JJ 10 26 28

2) 1 39

0 49 30 N. S.
\ App. dift. 21 47 51 N. S.

2) 0 45 53
01 42550 0 22 56'f L. S. 7.824347$
3713273 2

Log. 9.5S61148 =
Log. 9.5527587 =
Tab. IX. Log. 9.9990330

3855803 = S. 0000445 = 5.648695S
3570743 = D. 1373746

1374191 = 19.1380470

19.1379065 SB

1373746 2145 31,8 = 9.5690235
2

43 31 2\ = True diftance
3. Example

OF THE EFFECTS OF PARALLAX AND REFRACTION. 47

S. Example from the Requifite Tables, page 41 & 43, 3d Edition, ad fin*

App. alt. * 24 4S o „ True alt. * 24 45 57

3$ 12 30 Ho. Par. 56 15 J$) 13 20 42

2) 12 18 2) 11 25 15

~ Nat. fine 1071313 5 42 37§ L. S. 3.9978259

| App. dift. 25 44 17f — 4342618 2

Log. 9.7335131 = 5413936 = S. 0099004 = 7.99565 la

Log. 9.5147204 = 3271300 = D. 1765564

Tab. IX. Log. 9.9986500 1864568 = 19.2705783

19.2468835 == 1765564 Sine 25 3456 = 9.635289J

2

True diftance = 51 9 52

t. July 6th, 1790, at 9* 13' 15" A. M. apparent time, the apparent alti-
tudes and diftance of the fun and moon's centers were obferved as
follows: Moon's alt. 25° 29' Jl", Sun's alt. 15° 54' 5" diftance
66° 19' 32'', Moon's Ho. Par. 54' 2,5" regd the true diftance.

J\pp. alt. © 25 29 1 1 True alt. ]$ 26 16 28

' 0 l5 ;34< 5 Q 15 50 55

Difference 9 35 6 Tab. II. 0069802 10 25 33 Tab. II. 0082550

App. dill. 66 19 32 Tab. II. 2992304 2903825

Leg. 9.4657548 = 2922502 T. dift. 66 15 4 Tab. II. 2986375

Tab. IX. Log. 9.9972157 ' .

9.4629705 sfe 2903S25

Note. — In the three firft examples the computation is car-
ried on by the help of the tables that are in common ufe, but
in this kit example, by referring to the propofed table of tha
fquares of chords, under the title of Table II. fome idea may
be had of the labour required in the more improved method of
computation. There is nothing farther to add than that, if
after the many modern improvements in the way of clearing
the obferved lunar diftances of the effects of parallax and refrac-
tion, the prefent mode fhould be thought of utility, and worthy
of adoption, the neceflary tables, or at leaft that part which
Knew, will be published in a feparate oclavo volume.

Analyfis

48

ON THE PROPOLIS OR MASTIC OF BLE§«

Its general pre
pertie3 and ap-
plication.

Amlyfis of the Propolis or Maftic of Bees* By dr.
Vaucuelin.

mXc!8 °r bCe HE ProPoIis is wel1 known to be, (tie firft matter coleSc^

by the bees of a fwarm, newly placed in a hive. This 4<ib-
fiance, is refmous, duclile, adorant and of a reddiih brown
colour, more or lefs deep.

The propolis adheres fo ftrongly to the legs and feet ,of the-
bee, which has colle&ed it, that it is not able to free itfelvfrom
it. Other working bees, to whom this bee feems to^refent
its legs, carry off, with their jaws, this tenacious matter, and
apply it round the infide of. the hive, .particularly over aJJ the
projections: hence this name of propolis, i which figmfies in
the Greek before the city. ' '. 2 " h

This propolis is at, .firft foft and Veryi«extenfibfe;- 'rjiu't it
hardens, and at lad becomes very folid. It is not yet known
from what part of plantVit is extracted : it is believed' that it
comes from that fpecies of gum-refin whrcn coals and defends
mod of the buds, of trees and flirubs from wet. By Continu-
ing this work withinfide the hive, all the foreign bodies, which
are introduced into thejeommon habitation jand areVtoo heavy
to be removed to the outtide, are covered over w^lh this mat-
ter, and thus put out of the boundary.

The following are the obfervations made by Cit. Vauquelin
on this fubjeel, and which he has inferted in a report made to
the Society of Agriculture, in concert with Cit. Lafteyrie.

In the mafs it is blackiih; but it is femitranfparent when in
thin plates. The heat of the fingers is fufficient to foften it
and give it all the ductility of wax: but it is more ropy and
tenacious. Like wax it may be kneaded between the teeth,
without any perceptible tafte. Its odour is aromatic, refem-
bling that of melilot, of balfam of Peru, or of the Banana
poplar.

One hundred grammes of this fubftance were digefted, for
twenty-four hours", in very pure alcohol. The liquor accjuired
a deep red tint: and was thus filtered. Frefh fpirit of wine
was put to the refidue, and left to digeft again in the cold*
during twenty-four hours. As it had gained but little colour,

* Abridged in the Bulletin de la Societe Philomathique, from
the Memoirs of the Society of Agriculture of the Department of
the Seine.

5 a third

Analyfis :

Solution in al-
cohol :
filtration*

ON THE PROPOLIS OF MASTIC OF BEES. ^.Q

a third quantity of alcohol was added to the marc, then boiled
for a few minutes : and filtered quite hot, Six portions of al-
cohol were fucceffively added to the marc and boiled : finally
to deprive it of the fat matters it retained from fragments of
bees, as well as fome vegetable fubftances and grains of fand,
boiling fulphuric ether was poured on it, and the mafs was
prefled through a fine ftrainer. The refidue dried, weighed
J 4 grammes.

To obtain the fubftance which had been dhTolved by the Precipitate by
alcohol, the whole quantity that had been employed in theC0>m8*
different warnings was collected, and paffed through a fine
ftrainer, which flopped all the matter precipitated by the cold.
This refidue was wrapped in unfized paper and prefled ; when
dried and melted, it weighed 14 grammes.

All the alcohol was then diftilled and reduced to three- Diftillation gave
fourths of its quantity. The liquor which came over had an xSwfoStito
aromatic odour ; but it did not render water turbid, nor was which remain-
it acid. What remained in the retort was of a deeper colour. ed ln tne retort
t • • i ... , r , . , , ga"-'e a refinous

its precipitate by water was ropy like the relins which areob- precipitate by

tained by the fame means. By diluting this liquor with water water« The
and boiling it, a refiniform mafs was obtained on cooling, of a
red brown colour, femi-tranfparent and very brittle, which
weighed 57 grammes. The water in which this matter had
been diflblved, contained an acid.

This refinous mafs, or pure propolis melts readily on the Properties of
fire: it yields by diftillation a volatile oil, white and of a very the refin.
agreeable fmell. The fixed part then acquires a deeper colour
and becomes harder: it is foluble in fixed and volatile oils.
It is a true refin, very fimilar to balfam of Peru, of which it
contains the acid.

The 14 grammes of precipitate produced by cooling, were The firft pre-
true wax, poflefiing all its properties. It remains to be known ciPitate was
whether this wax is actually mixed with the propolis by the
bees ; or whether, in collecting the latter with too little care
the wax is not united to the refin.

grammes.

Pure wax -

14

Component

Pure refin of propolis -

57

parts.

Refiduum of extraneous bodies

14

Lofs; acid j aroma,. -

15

100
Vol. V..— May. E Memoir

50

ON CUTANEOUS AERIFORM TRANSPIRATION.

XI.

Introdu&ory
observations.

Memoir on the cutaneous aeriform Tranfpiration. Read at the
public Sitting of the Society of Health, at Grenoble, the Mh
Frimaire, in the year 11. By Cit. Trousset, M. D. etc.*

JlHYSICIANS have in all ages endeavoured to afcertain
the influence of the air on the human body ; but how it is to
be conceived that the ancients, who were not even acquainted
with the gravity of that fluid, fhould be able to determine its
action ? For the fame reafon, if we except Hippocrates, who
in his work fays plainly that the air is digefted in the lungs
like the food in the ftomach, his cotemporaries and their fuc-
ceflbrs have only left behind them, on this fubject, incoherent
fancies, often ridiculous, and always wrong ; the offspring of
imaginations undirected by any certain experience.

If it were my intention to confider the influence of the air,
in all its relations, I fhould firft attend to refpiration, a function
of fuch importance, that without it life could not be Curtained,
while alone it would require fome time for its difcullion.

But modern chemifts, after having made an accurate analy-
fis of atmofpheric air, have formed a theory of refpiration, fo
ingenious, fo complete, and founded on fuch exact experiments,
that every effort which has hitherto been made to overturn it
has only ferved to render it more folid.

I could, then, only repeat here what has been already faid
by Lavoifier, Seguin, Crawford, Fourcroy, Chaptal, &c. for
this fubject has been to well elucidated by the labours of thefe
celebrated chemifts, that it may be faid to be exhaufled ; and
their doctrine, on this topic, has been fo difTeminated, that, at
prefent, it is known and adopted by all who employ themfelves
in fcientific purfuits ; I fhall, therefore, difpenfe with a repe-
tition that would be faftidious and ufelefs.
Whether gas But though the operations of the lungs are very accurately

th T-'tted fr°m known, the functions of the fkin have not been fo diftinctly
elucidated. Independent of the cutaneous tranfpiration (o
carefully and diligently obferved by Sanctorius and many others,
we may enquire whether one or feveral aeriform fluids efcape

* Annales de Chimie, XLV. 73.

bv

ON CUTANEOUS AERIFORM TRANSPIRATION". $\

by the fkin ? And if fo, what may be their nature ? Thefe are
the queflions I propofe to examine in the preient memoir.

The ancients did not even fufpect the cutaneous tranfpiration
of air, and make no mention of it in any of their works.

The count de Milly firfi announced, in 1777,* the dif- C. de MUlyfirfc
covery of an elaftic fluid which patTes off by the fkin. He obferved ic*
afferts that, being in a warm bath, half a pint might have been
collected in the fpace of three hours; and from his analyfis,
which was both inaccurate and very incomplete, he concluded
that it was fixed air (carbonic acid gas.)

M. Ingenhouz, fome time afterwards noticed this tranfpi- D. Ingenhouz.
ration of air by the fkin, but he believed it to be phlogifti-
catedair. (nitrogen gas.)

M. M. Prieftley and Fontana repeated the experiments of Prieftley,
the two preceding philofophers, but could not perceive any Fontana*
aeriform emanation from the {kin.

M. Jurine, furgeon at Geneva, intending to be a competi- jurine.
tor for the prize propofed by the Royal Society of Medicine, f
repeated the experiments of M. M. Milly and Jngenhouz, not
only on himfeif but on feveral individuals of all ages, ufing
different kinds of water and varying the temperature; he in-
forms us that he never difcovered any emanation of air. Pre-
fuming that the water, by its preffure might have obftrucled
the paffage of the air; or that it contracted the exhaling air-
veflels of the Ikin, he continued his inquiries, by varying the
proceffes before ufed by M. M. Prieftley and Fontana, and he
thought he had proved by experiments, the inaccuracy of
which may be eafily (hewn, that a fmall quantity of fixed air
(carbonic acid gas) is conftantly emitted by the ikin.

Cit. Fourcroy expreffes himfeif thus : u it is not true, as fome Fourcroy.
moderns have afferted, that elaftic fluids and particularly car-
bonic acid gas are tranfpired by the fkin" *.

Such, a very few years ago, was the ftate of the queftion
which now engages us. Incorrecl experiments, the contra-
dictory refults of which were difputed either wholly or in part,

* Memoirs of the Royal Academy of Sciences at Berlin, for
1777, p. 32.

t See Hiftory and Memoirs of the Society of Medicine, Vol.
X. p. 54, and fol.
* Fourcroy, Syftem of Chemical Knowledge, Vol. IX. p. 203.
E 2 left

52

ON CUTANEOUS AERIFORM TRANSPIRATION.

Obfervation of
gas emitted
from the fkin in
the bath.

left philofophers in uncertainty, and appeared to require new
obfervations, in order that the opinions of chemifts might be
finally fettled on this fubjeft.

I had often meditated on this fubjecl with an intention of en-
gaging in it, when in the fpring of the year eight, while attend-
ing one of my patients in the bath, I perceived that he was
entirely covered with bubbles of air ; the hairs on his body
were furrounded with bubbles decreafing from the bafe to the
fummit, fo that many of them prefented the appearance of
pyramids more or lefs elevated. I difplacedall thefe bubbles,
and in half an hour afterwards there appeared an equal quan-
tity.
It was nitrogen. On witnefling this phenomenon, I engaged my patient to
continue the bath, and collected fucceffively feveral jars of
this gas, which I examined with much care and at different
times. I was fatisfied that it was perfe&ly pure nitrogen gas,
without any mixture of carbonic acid.

I wifhed then to know whether this phenomenon was ge-
neral, or depended on the pathologic itate of the fubject.
Experiments made on mylelf and on feveral other individuals
did not offer any thing fimilar.

I communicated my experiments and their refults to Cit.
Fourcroy, in the beginning of the year nine, who encouraged
me to repeat them. Stimulated by the approbation of this ce-
lebrated profefTor, I undertook the talk. It was not enough
for me, in fa£i, to be certain of the accuracy of my experi-
ments, it was alfo neceffary to convince others.

In the fpring of the year nine, having collected a certain
quantity of this gas with great care, I rilled a fmall glafs jar
10 lines in diameter, and eight inches high, with it; a taper
was inftantly extinguifhed in it eleven times fucceffively.

I endeavoured to decant a fimilar meafure of this gas, but
could not fucceed, which I could eafily have done had it been
carbonic acid.

It was paffed through lime-water without rendering it turbid
or diminifhing in volume.

It underwent no change with ammoniacal gas.

It did not affect blue vegetable colours.

Phofphorus which had remained immerfed in it for more than
a month, was Scarcely diminifhed in bulk.

I judged

Detail of expe-
riments on this

ON CUTANEOUS AERIFORM TRANSPIRATION. 53

I judged thefe experiments to be more than fufficient to (how
that it was nitrogen gas.

I again tranfmitted the refult of thefe new experiments to
Cit. Fourcroy, in Fru&idor of the year nine; probably his
occupations have prevented him from fending me any reply.

Having fince that period reflected much on the importance
of this difcovery, I have continued to attend to it, but my
notions are entirely changed with regard to the confequences
to be drawn from it.

Formerly in the letters written to Profeflfor Fourcroy, and Tne emlffion of
efpecially in the latter, I confidered as a particular facl, de- J ordered as a
pendant on the pathologic ftate ; at prefent I am compelled general pheno-
to conlider it as a general phenomenon belonging to the whole menon'
human fpecies.

111. Becaufe it is probable that the gas fo abundantly yielded
by the fkin of M. le Comte de Milly, was nitrogen gas, as
may be feen by an attentive perufal of his memoir.

2d. M. Ingenhouz, convinced by his own experiments, that
an aeriform fluid is emitted by the fkin, believed if to be phlo-
gifticated gas (nitrogen gas.)

3d. My experiments confirm the fufpicion of M. Ingen-
houz.

4th. Some time ago I met with another perfon who tranf-
pired abundantly in the bath j the bubbles with which he is
conftantly covered are not dilTolved in the water, it is proba-
bably nitrogen gas, I acknowledge, however, that I have
never made any exacl experiment on it.

. 5th. The experiments made by M. M. Prieftley, Fontana
and J urine, which confided in placing open veflels under their
arm-pits, do not prove any thing in oppoiition to what I have
before advanced, becaufe it is evident that thefe veflels being
full of atmofpheric air, it could not be difplaced by nitrogen
gas, whofe fpecific gravity is lefs ; while this effect would
have taken place with carbonic acid gas, if, as M. Jurine
infers from his experiments, that this laft fluid is conftantly
difengaged by the fkin.

Thofe made by M. Jurine, by placing his arm in a glafs cy-
linder, are not more conclulive, becaufe they were performed
with a view to prove that it was carbonic acid gas which ef-
caped, and the proper means were not taken to point out the
prefence and the quantity of nitrogen gas, whofe difengage-
ment he did not even fufpeft.

M

54 SCIENTIFIC NEWS.

The water fup- But why was not this phenomenon, which I believe to be
SfidnmoftftrUaSenera1' obferved by M. M. Prieftley, Fontana, Jurine, &c.
perfons. and why is it not equally perceptible in all individuals placed

in the fame circumftances ? It is probable, as I have faid in
the beginning of this memoir, after M. Jurine, that the water
acting by its weight upon the exhaling air-veffels of the fkin
differently upon different fubje&s, may obftruct the paflage of
all gafeous bodies in the greateft number of individuals.

I fliall here conclude this memoir, which I might have ex-
tended much farther, had I been inclined to difcufs all the
queftions to which the phenomenon naturally gives birth ; but
having had no other defign but to call the attention of natural
philofophers to the fubjeel, and fatisfied with having began
the refearch, I leave the completion to more fkilful chemifts.

SCIENTIFIC NEWS.

Decree of the French Government relative to tlie new Organization
of the National Injlitute.

New organiza- J- ^^ government of the republic, upon the report of the
tion of the minifter of the interior, having advifed with the counfei of
French inftitute. ftat<^ decree as folIowg .

I. The national inftitute at prefent divided into three clafles,
{hall from henceforth be divided into four ; that is to fay,

Firft Clafs. Clafs of phyfical and mathematical fciences.

Second Clafs, Clafs of French language and literature.

Tliird Clafs. Clafs of hiflory and foreign literature.

Fourth Clafs. Clafs of the fine arts.

The actual members and foreign aflbciates of the inftitute,
fhall be divided into thefe four claffes.

A committee of five, members of the inftitute, named by
the Firft Conful, fhall adjuft this divifion, which fhall be fub-
mitted to the approbation of government.

II. The firft clafs fliall be formed of the ten fe&ions which
at prefent compofe the firft clafs of the inftitute, with a new
fc&ion of geography and navigation, and eight foreign affo-
ciatos.

Tho

Mathematical
Sciences -

Phyfical Sci-
ences - -

SCIENTIFIC NEWS. - 55

The feclions fhall be compofed and called as follows : ^ew organiza-

Geometry - - - - 6 members, tion of the
Mechanics - 6 ditto. French inftitu*;

Aftronomy - 6 ditto.

Geography and Navigation - 3 ditto.
„ General Phyfics - - - 6 ditto.

-.Chemiftry - 6 members.

Mineralogy - - - - 6 ditto.
Botany . . - - 6 ditto.

Rural Economy and Veterinary Art 6 ditto.
Anatomy and Zoology - - 6 ditto.
*- Medicine and Surgery - - 6 ditto.
The firft clafs fhall appoint, with the approbation of the
Firft Conful, two perpetual fecretaries, one for the mathema-
tical fciences, the other for the phyfical fciences. The per-
petual fecretaries fhall be members of the clafs, but (ball not
form a part of any fection.

The firft clafs may elect fix of its members from the other
claffes of the inftitute.

It may name an hundred correfpondents felected from the
learned men of France and foreign countries.

III. The fecond clafs fhall be compofed of forty members.
It is particularly charged with the compofition of the

dictionary of the French language. It fhall examine with
refpect to language, the important works of literature, hiftory
and the fciences. The collection of its critical obfervations
fhall be publifhed at leaft, four times in a year.

It fhall name from its own body, and with the approbation
of the Firft Conful, a perpetual fecretary, who fhall continue
to be of the number of the forty members which compofe it.

It may elect twelve of its members from the other dafTes of
the inflitute.

IV. The third clafs fhall be compofed of forty members and
eight foreign alTociates.

The objects of its refearches and laboucs fhall be learned
languages; antiquities and monuments; hiftory and all the
moral and political fciences connected with hiftory. It fhall
particularly apply itfelf to the enriching of French literature
with the works of Greek, Latin and Oriental authors, which
have not yet been tranflated.

It fhall employ itfelf in the continuation of diplomatic col-
lections.

It

56 SCIENTIFIC NEWS.

New organlza- It (hall name from its own body, under the approbation of
French inAitute. ^e ^r^ Conful, a perpetual fecretary, who (hall be of the
number of the forty members which compofe the clafs.

It may elect nine of its members from the other clafles of
the inftitute.

It may name (ixty correfpondents, natives or foreigners.

V. The fourth clafs (hall be compofed of twenty-eight
members and eight foreign aiTociates.

They (hall be divided into fections, defcribed and formed as
follows :

Painting - - - - 10 members.

Sculpture ----- 6 ditto.
Architecture 6 ditto.

Engraving ----- 3 ditto.
M ufic (composition) 3 ditto.

It (hall appoint, with the approbation of the Firft Confu!,
a perpetual fecretary, who (hall be a member of the clafs, but
fliall not be a part of a fection.

It may elect fix of its members from the other clafles of the
institute.

It may name thirty-fix correfpondents, national or foreign.

VI. The foreign aflbciated members (hall have a delibera-
tive voice only on fubjects of fcience, literature and the arts ;
they (hall not form part of any fection, nor interfere in any
ufage.

VII. The prefent actual national aiTociates of the inititute
(hall form part of the one hundred and ninety -fix correfpon-
dents attached to the clafles of the fciences, belles lettres, and
fine arts.

Correfpondents may not alTume the title of members of the
inftitute.

They (hall lofe that of correfpondent when they (hall be
domiciliated at Paris.

VIII. Nominations to vacant places fliall be made by each
clafs in which the vacancy happens, the perfons elected (hall
be confirmed by the Firft Conful.

IX. The members of the four clafles fliall enjoy a reciprocal
right to aflift at the particular fittings of each clafs, and may
deliver lectures when they are requefted.

They fliall' re-unite four times in a year into one body, to
communicate their proceedings.

They

SCIENTIFIC NEWS 57

They (hall elecl in common the librarian and under librarian New organiza-
of the inftitute, as well as all thofe agents who belong to the Sonof^.
inftitute in common.

Each clafs (hall prefent for the approbation of the govern-
ment, the particular ftatutes and regulations of its internal
police.

X. Each clafs fliall hold one public fitting every year, at
which the other three fliall affift.

XI. The inftitute (hall receive annually from the public trea-
fury 1 ,500 fr. for each of its non-aflbciated members, 6,000
fr. for each of its perpetual fecretaries ; and for its expences,
a fum which fliall be fixed every year, upon the demand of the
inftitute, and comprifed in the eftimates of the minifter of the
interior.

XII. There fliall be an adminiftrative committee for the in-
ftitute, compofed of five members, two from the firft clafs,
and one from each of the others, named by their refpeclive
clafles.

This committee (hall regulate in the general fittings pre-
ferred by Art. IX. all that relates to the adminiftration, to the
general expences of the inftitute, and to the divifion of its
funds between the four clafles.

Each clafs (hall afterwards regulate the application of the
funds afligned to it for its expences, as well as all that concerns
the printing and publifhing its memoirs. [ /

XIII. Every year the clafles fliall diftribute prizes, the num-
ber and value of which (hall be regulated as follows :

The firft clafs, a prize of 3,000 francs.

The fecond and third clafs, each a prize of 1,500 francs.

The fourth clafs, grand prizes of painting, fculpture, archi-
tecture and mufical competition. Thofe who (hall have gained
one of the grand prizes, (hall be fent to Rome, and main-
tained at the expence of government.

The above decree was followed by a fecond, appointing
the members of the different clafles, and regulating the days
of their meeting.

The fittings of the firft clafs are to be held every Monday ;
thofe of the fecond clafs every Wednefday ; thofe of the third
every Friday ; and thofe of the fourth every Saturday.

The fittings are to be held in the fame place, and to Iail from
three o'clock till five.

4 The

58 SCIENTIFIC NEWS.

Neworganira- The firft: fitting of the firft clafs, in Vend^miare; that of
FrLlinftitutc. the fecond> in Nivofe ; that of the third, in Germinal; and
that of the fourth, in Meflidor ; are to be public.

In conformity to thefe decrees, the national inftitute has been
re-organifed.

The firft clafs, that of phyfical and mathematical fciences,
held its firft fitting on Monday the 11th Pluviofe.

C. Chaptal was chofen prefident; and C. Cuvier, perpe-
tual fecretary of the feclion of phyfical fciences ; and C. De-
lambre, for that of mathematical fciences.

The committee to propofe regulations are CC. Laplace,
Monge, and Fourcroy.

The fitting of the fecond clafs, that of French language and
literature, was held on Wednefday the 13th.

Prefident: C. Luc ien Bonaparte. Perpetual fecretary : C.
Suard.

Committee, &c. CC. Morallet, Bigot-Preameneu and
Andrieux.

The third clafs, that of hiftory and foreign literature, on
Friday the 15th.

Prefident: C. Le Brun. Perpetual fecretary: C. Dacier.

Committee, &c. CC. Paftoret, Dutheil, and Sylveftre de
Sacy.

The fourth clafs, that of the fine arts, on Saturday the 16th.

Prefident : C. Vincent. Perpetual fecretary : C. Labre-
ton.

Committee, &c. CC. Vincent, Danon, Dufourny, Gretry
and Moitte.

Galvanic Information.

Galvanic re- THE Moniteur of the 2d Floreal (April 22,) fays "the
fearches. galvanic fociety continues its labours with zeal and with the

mod marked fuccefs."

" Cit. Gautherot has performed a fuccefiion of experiments
tending to prove that the developement of electricity is pro-
portionate to the furfaces.

" New difcoveries have been publilhed by Profeifor Aldini
relative to the exiftence of a galvanic atmofphere, and to the
contraaibility of the heart.

¥ Cit.

/ SCIENTIFIC NEWS. §Q

" Cit. Nauches, the prefident, with his co-labourers Bo*«
net and Pajd-Laforet, have fucceeded, by the affiftance of
two homogeneous metallic conductors, in fubtracting the elec-
tric fluid of the brain, and fpinal marrow of an ox, immedi-
ately after its death, and conveying it to the thighs of a frog,
•where it produced mufcular contractions. This operation was
equally fuccefsful upon the palpitating mufcles, and could not
be prolonged beyond a quarter of an hour after death. The
fenator Lamartilliere has given an explanation of the difen-
gagement of mucofity by one of the poles of the pile, and
has made it appear that depends on a chemical decompo-
fition.

Cit. Paroifle took notice that, of the mufcles, the dia-
phragm preferved its galvanic excitability the longefl.

Cit. Izaer gave an account of the conftru6tion of a pile,
difcovered by Cit. Alizeau, in which the roundels, impreg-
nated with a faline folution, are replaced by moiftened fait,
and which preferves its power for a month, without being
cleanedf

The committee of medical application, confiding of M. M.
Guillotin, Dudaujon, Petit-Radel, &c. have made a number
of experiments on afphixia produced by ftrangulation.

f? The application of galvanifm to the cure of difeafes which
had been fufpended on account of the unfavourable feafon, is
to be refumed in a ward which has been appropriated, by the
minifter of the interior, to that purpofe, in the hofpital of the
Ecole de Medicine, and in a laboratory belonging to the fo-
ciety."

.

Prize Quejlion.

The Society of Arts and Sciences at Utrecht, has propofed thefol- prize queftion#
lowing Prize Quejlionfor the Year J 803. Eleftricity.

**, What is the true nature of the electric matter ? Is it a
compound ? What are the chemical changes it undergoes,
when united with other bodies, and which it produces in thofe
bodies ?"

The prize, which is to be adjudged on the firft of October,
1803, confifts of 30 ducats; and the memoirs are to be ad-
drefled to Dr. Luckman, at Utrecht.

Hermaphrodite

60 SCIENTIFIC NEWS.

Hermaphrodite Fijli.

Hermaphrodite In Vol. XXI. of the " New Tranfaclions of the Royal Aca-
demy of Sciences at Stockholm" is an account of an eel (gadus
lota) in which eggs and foft roe were found at the fame time*
It is by profeflbr J. G. Pipping. c

Experiment calculated to prove that the Laws of Gakanifm appear
to differ from thofe of Eleclricity. By Lag rave, Member
of the Galvanic Society *.

Suppofed differ- The experiments which I fubmit to the public have ap-

the^eaHrLd Peared to me to differ from the Iaws of eledricity, in this re-
galvanic fluids, fpect, that the galvanic fluid feeks the mod: intimate affinities,

and that electricity appears to endeavour to efcape at the firft

touch.

My Experiments were as follows :

Experiments I raifed a pile of feventy pair of plates, of copper and

du&or. °nSCOn"zmc> perfectly free from oxidation ; I then applied, to the

zinc end, a conductor fix ells long, which 1 patted once round

my arm, then twice round my body, above my cloaths, from

whence I conducted it round my thigh and my leg, alfo once

round each, and fecured its lower extremity to my foot, in a

Galvanic mock bucket of warm water : I wetted my right hand, (the great

perceived m the conductor was round my arm, thi^h and leg, on the left fide)
moiftened hand ; Jr ° 6> '

and having brought my tore-nnger to the copper end, J ex-
perienced the moft lively (hock in this hand and arm, but felt
nothing from the great conductor of the zinc end. Surprized
not having had the flighteft fenfation from this pole, I repeated
the experiment with the fame effect ; and at firft believed
that, in this cafe, the galvanic fluid was governed by the laws
of electricity ; that is to fay, that it was difpofed to pafs off
in the foot, when by the fhorteft way ; but I quickly difcovered another caufe,
made with sTfe- wnen> on taking a copper wire, two feet long, in my right
condor* con- hand, and placing it in contact with the copper pole, I felt
ttor, the fhock in the foot immerfed in the bucket of water.. I was

equally aftonifhed at receiving the fhock in my foot, notwith-

* From the Journal de PhyGque, Ventofe, An. XI.

withftanding

SCIENTIFIC NEWS.

61

notwithstanding the wire was fo repeatedly wound round my
arm, my body, my thigh, and my leg, without yielding, in
this long courfe, the flighteft effect : I repeated this experi-
ment with the fame fuccefs ; and foon difcovered that the
fhock I received in my foot, to the exclufion of the other
points of contact, was only occafioned by the affinity of the
water for the galvanic fluid, and becaufe it foftened the epi-
dermis : but that which convinced me of it, was, that on and in various
putting drops of water alternately, on the turns of the wire, J^^" cJ^ft
and then bringing that connected with the copper pole in con- conductor, by

tad with it, I inftantly felt the (hock at the places where the P!acinS droPs of
. „ . . r r • water on it.

drops or water were put, and experienced no ieniation in

my foot. I repeated this experiment, putting a drop of water
upon the feveral turns of the wire, and connecting the cop-
per pole with it : fimilar effects were produced without my
perceiving the flighteft fenfation lower down; although I had
neglected to wipe off the moifture occafioned by the dif-
ferent drops of water. I obferve, .in this operation, the rule Conclufioas.
which governs electricity, that is to fay, that it is difpofed to
give the fpark by the fliorteft way ; but, on the other hand, I
alfo find, that the galvanic fluid is inclined to feek an affinity
which does not feem to agree with the electric fluid; becaufe,
we obtain a fpark from the firft contact, but here, the galvanic
fluid paffes through a confiderable fpace of the moft intimate
points of contact, without lofmg any of its power, and pro-
duces no fenfation until it has found an affinity favourable to
its difengagement. I felt alfo the moft diftinct effects, on
taking a wire of great length in one hand, with which I
touched the pofitive pole, as in the former experiment I made
a long circuit with it entirely round my room, and having
brought back the end to my left hand, I put the right in
contact, and felt a fimilar fhock in my right hand, but if I
took a wire of two feet in that hand, without being careful
to wet it as well as the other, I felt nothing. The fluid
pafled through the long circuit of the wire to reach that
point which offered the greateft affinity ; thus I placed a con-
ductor at either pole, and uniformly felt the lhock from that pole
which I touched with my naked and moiftened hand.

Such were my observations on this feries of experiments.

It will be the greateft fatisfaction to me, if they fhould give
rife to fuch clear opinions as may tend to the good of humanity
and to the progrefs of the arts and fciences.

Galvanic

62 SCIENTIFIC NEWSj

Galvanic Experiments, tending to afcertain the Exijlence of Tib*
Fluids in the Animal Economy, the one pojitive and the other
negative, which, by their Union, appear to produce the Agency
of Vitality, by La Grave, Member of the Galvanic Society *.

Galvanic pile BEING defirous of fatisfying myfelf concerning the pheno*

cle'and branT * mena which are exhibited in the experiments made on frogs;
with cloth by bringing part of each of their thighs in contact upon the

interpoied. cervical nerves, and perfuaded that this fact could only pro-
ceed from the concurrence of two fluids, the one pofitiveand
the other negative, as we find it in the pile of Volta, I felt
inclined to form a pile, compofcd of the nervous and mufcular
parts alternately. With this view, I procured a body, and
prepared and uncovered, as much as poffible, a certain num-
ber of the pectoral and intercoltal mufcles, which I cut into
the form of difcs; I then took the brain, not being able in this
experiment to make ufe of the nervous cords, and cut, as thin
as I could, the fame number of difcs as I had prepared from
the mufcular parts. Of thefe I raifed a pile to the number of
fifteen or fixteen couple, placing between the pairs, pieces of
cloth moiftened in falted water. It was in vain that I endea-
voured to raife my pile with the pieces of cloth ; the foft parts
of the brain and their flexibility prevented it. I attempted it
feveral times, becaufe the experiment appeared to me to be
curious, but I could not fucceed. Being ftijl defirous to over-
come thefe difficulties, it occurred to me that pieces of leather
or of hat might fulfil my wifhes, as they poflefs a proper ftifF-

ti , .». , nefs to fupport the foft part of the brain. In fact, I tried

r;at fubuituted rr *

/oi icth. both, but thofe of hat foon obtained the preference over the

pieces of leather, becaufe they have the quality of being po-
rous, of retaining the moifture better, and of poflefling a de-
gree of elafticity, which the leather has not. I then made
fbme frefli preparations of mufcleand brain, and raifed a pile,
making ufe of difcs of hat for feparating them ; but after hav-
ing raifed my pile to twenty couple, I experienced new diffi-
culties. The cerebral parts were crulhed and began to efcape
from the weight of the pile. I need not obferve that I took
care to examine whether this fmall number of pairs was fuf
ficient to produce the tafte. I obtained no effect from the

* From the Journal de Phyfique, Ventofe, An. XI.

twentieth
2

ACCOUNT OF NEW BOOKS. (JJ

twentieth couple: it was neceflary therefore to determine to

abandon the experiments, or to devife fome other mode. For Other contri-

this purpofe, I thought of making a layer of fmall firing thevauces*

length of the pile, tied to the glafs of the infulater of the pile

of Volta to fuftain my rounds and my pairs of the flefhy and

cerebral parts; this idea fucceeded. I continued then to

raife my pile upon thefe new fupports : I was aftonifhed and

much more impatient to perceive nothing at the thirtieth couple.

Obftinately bent on fucceeding or being convinced that my

opinion was erroneous I perfifled and continued to heighten

my pile ; I did not perceive the leaft effecT; until I had added

the fortieth pair. Encouraged by this fuccefs, I redoubled At the fiftieth

my attention and was thoroughly convinced of the exigence ^ perCefved

of the tafte at the fiftieth couple. Neverthelefs I continued and at the fix-

increafing the pile to the fixtieth, and the evidence of its ticth decifive*

effects was moft decifive.

Such were my difagreeable but curious experiments.

ACCOUNT OF NEW BOOKS.

TranfaStions of the American Philofophical Society held at Phila- Americas phi-

delphia for promoting Ufeful Knowledge. Vol. V. 1 802, lofophical tranf-

„~~,-/. ■ ait ions.

p.p. 328. Quarto.

A HE contents of this volume are I. Experiments on the
million of acids, and other liquids, in the form of vapour,
over feveral fubftances in a hot earthern tube*-— II. Experi-
ments relating to the change of place in different kinds of
air through feveral interpofing fubftances — III. Experiments
relating to the abforption of air by water— IV. Mifcellaneous
experiments relating to the do&rine of phlogiflon — V. Ex-
periments on the production of air by the freezing of water —

VI. Experiments on air expofed to heat in metallic tubes —

VII. Some account of the poifdttous and injurious honey of
North America — VIII. On the ephoron leukon, ufually called
the white fly of PafTaick river — IX. Remarks on certain
articles found in an Indian tumulus at Cincinnati, and now
depofited in the mufeum of the American philofophical
fociety — X. A drawing and defcription of the clupea tyrannus
and onifcus prseguftator (in the Prefent Number) — XL A

defcription

f>4> ACCOUNT OF NEW BOOKS.

defcription of a newly invented globe time-piece — XII. A
defcription of the pendant planetarium — XIII. On the ufe of
the thermometer in navigation — XIV. Sur les vegetaux, les
polypes et les infe&es — XV. Memoir on the analyfis of black
vomit — XVI. Obfervations on the foda, magnefia and lime,
contained in the water of the ocean ; (hewing that they operate
advantageoufly there by neutralizing acids, and among others
the feptic acid, and that fea-water may be rendered fit for
wafhing cloaths without the aid of foap — XVII. Defcription
of a Hopper for the openings by which the fewers of cities
receive the water of their drains — XVIII. A memoir on
animal cotton, or the infect fly-carrier (fee Phil. Journal for
April) — XIX. Note concerning a vegetable found under
ground — XX. Agronomical and thermometrical obfervations,
made at the confluence of the Miffiflippi, and Ohio rivers —
XXI. Agronomical and thermometrical obfervations made
on the boundary between the United States and his Ca-
tholic Majefty — XXII. Obfervations on the figure of the
earth — XXIII. Defcription of fome improvements in the
common fire-place, accompanied with models offered to the

confideration of the American philofophical ibciety. Apr

pendix, I. An account of a method of preventing the pre-
mature decay of peach trees. II. Defcription of a method
of cultivating peach-trees, with a view to prevent their pre-
mature decay ; confirmed by the experience of forty-five
years, in Delaware ftate and the weflern parts of Penfyl-

Parkinfon's Tfie Chemical Pocket Book ; or Memoranda Chemica ; arranged
in a Compendium of Chemijlry, By James Parkinson,
Holborn. The third Edition, zvith appropriate Tables and
Accounts of the lateft Difcoveries. \ 803 p. 272. 12mo.

THE character of this work is already eftablifhed. In the
prefent edition the neweft difcoveries are inferted. The
author has adopted the nomenclature of Chenevix.

A

JOURNAL

OF

NATURAL PHILOSOPHY, CHEMISTRY,

AND

THE ARTS.

JUNE, 1803.

ARTICLE L

A Report of the State of His Mujejly's Flock of Fine-wooled Spa±
ni/h Sheep during Vie Years ISOOand 1801 ; with fome Account
of the Progrefs that has been made towards the Introduction of
that valuable Breed into thofe Farts of the United Kingdom-
where fine Clothing Wools are grown with Advantage. By the
Right Hon. Sir Joseph Banks, Bart. P.R.S. %c. %c*.

vJN the 9th of June, 1800, when his majefty's Spanifh flock State of his mai
was ftiorn, it confifted of 1 00 ewes and wethers, which pro--foc^sof ^"'
duced as follows : June 9, 1800.

Wool wafhed on the (beeps' back - «• 398 lb.
Lofs in fcowering - - - - * 104-
Amount of fcowered wool <* 294

"Which produced, when forted, prime 2341b. at 5/. per lb. 1

choice 34* at 3 j. >65l. 11/.

fribbs 26, at 1/. U. J

• From a printed copy with which I was favoured by Sir Jofephi
In our Journal, Vol. IV. p. 289 (Oft. 1800) the reader will find
a copy of a projeft for extending the breed of fine-wooled Spanifb
jheep, now in tbepojfeffion of his majefiy, into all parts of Great Britain
where the growth of fine clothing wool is found to be profitable, which
Was alfo drawn up and circulated by the fame gentleman. The pre-
fent report may be confidered as a fequel to the interefting hiftory*
and propofal contained in the former paper. W. N.

Vol. V.— June. F Eight

56 STATE OP HIS MAJESTY'S EINE-VVCJOLED SPANISH SHEET.

Sheep difpofed .Eight rams and nine ewes were this year difpofed of, which

breed, in 1800. were a^ tna^ could be fpared from the flock. Two of the rams

went into Dorfetfhire, where the breed is much approved by

fome fkilful judges of Cheep, and feems likely to produce con-

fiderable advantage by croffing with the common fheep of the

country.

Mr. Bridge's Mr. Bridge, of Winford Eagle, communicated this year the

improved value rem^ °f an experiment he had made on three kinds of fheep,

of fheep and their viz. Dorfet, half Spanifh and half Dorfet, and half Spanifh

He kept thefe fheep from the year 1798, when they were
lambed, till February 1 800, when they were butchered as fat
fheep; and having valued them in June 1798, he found the
carcafes of each fort, with two years wool which had been
fhorn from them, to yield at that time the following increafe
in value :

Real Dorfet 4/. 5s. 6d.

Half Spanifh half Dorfet - - 4 3 8

Half Spanifh half Mendip - - 3 19 2
In thefe experiments Mr. Bridge's woolflapler values the Dor-
fet wool at Is. 2\d. a pound, and the half Spanifli wool at
Is. 4df . only ; but as the Spanifh crofs in both cafes increafed
the quantity of wool, and as half Spanifli wool has nevef,
when its value was properly known, been fold for lefs than
Is. 9d. and generally more than 2s. a pound, there can be no
doubt that the improvement in value, arifing from the crofs,
is in both cafes confiderable.
Mr. Ridgway's Mr. J. Ridgway, of Upperton, in the parifh of Yazor in
ftaternentof Herefordfhire, communicated an experiment, in which two
fheep, the one a Ryeland, and the other half Spanifli and half
Ryeland, of equal weights, were fed by him together ; the
half Spanifli fheep produced in a year 2 lb. 12ozs. more wool
and 5 lb. more mutton than the Ryelander. This gentleman,
whom his majefly gracioufly permitted to have rams from the
Spanifli flock fome years ago, has alfo fhewn by his accounts
that the wool of his flock of about 16 fcore fheep, has beenfo
much increafed both in quantity and in value by the Spanifli
crofs, as to have produced nearly twice as much money for
each clip after the Spanifli blood was eftablifhed in it, as it
ufually did before.

Ii%

j7*>.

STATE OF HIS MAJESTY'S FINE-WOOLED SPANISH SHEEP. (J7

In June 1801, the Spanifh flock confined of 108 ewes and His majefty'a

wethers SPanifh flock»

Wetners' Junei8oi.

Which produced in wool, wathed on the {beeps' back 397lb.
Lofs in fcowering - - - - - - 112

Amount of fcowered wool - 285

Which produced, when forted, prime, 237ID. at 5*. 6d. per lb.
choice, 31, at 31. 6 d.
fiibbs, 17, at is. yd.
The wool of the rams and fatting wethers which had been
kept feparate, was prepared for fale at the fame time, and
produced in

Wool wathed on the flieeps' back - - 220lb.
Lofs in fcowering - - - - - 82

Amount of fcowered wool - - - 138
Which produced, when forted, prime, 96lb. at 5s. perlb. 1

choice, 30, at 5s. 6d. > 30/. 6s,
fribbs, 12, at Is. 9d. 3
This year, eight rams and twenty-two ewes were fold. If Sheep difpofed
the foot rot had not unfortunately damaged the rams very ma. of to extend the
terially, more of them would have been difpofed of. It is,
however, obfervable, that although the rams that are kept at
Windfor, in rich land are occafionally attacked by this ha-
raffing difeafe, the ewes and wethers that feed on the dry and
hilly paftures of Oatlands have never been fubjed to lamenefs
of any kind.

Eleven wethers that had been fent to the marfhes, in order Account of the
to try the efted of rich pafture in fattening flieep of this breed, ?"e^n? and
were flaughtered this year by Mr. King of Newgate Market, wethers.
previous to the Smithfield meeting, which ufually takes place
the week before Chriftmas. Two of the carcafes were given
to perfons who had been ufeful in afcertaining the value of the
Spanifh breed ; the remaining nine were fold to Mr. Giblet,
butcher, in Bond Street, whofe judgment in fele&ing, and
liberality in purchafing the belt carcafes, is well known, both
to thofe of whom he buys, and to thofe who buy of him. The
fale bill is as follows :

1 (heep, 6 ftone 6 lb. at 6s. per none
1 ditto, 7 0 6s. -

I ditto, 6 1 6s. -

1 ditto, 7 2 6s. -

1 ditto, 5 6 6s. -

P2

£.

s.

d.

2

0

6

2

2

0

1

16

9

2

3

6

1

14

6

9

17

3

1 (beep

X-

*.

d.

9

17

1

1

11

6

1

15

9

1

13

p

1

17

6

0

11

0

2

3

0

flg STATE OF HIS MAJESTY'S FINE-WOOLED SPANISH SHEEP.

Brought over,

1 fheep, 5 ftone 2 lb. at 6s. per Hone

1 ditto, 5 7 6«. -

1 ditto, 5 4 6^. -

1 ditto, 6 2 6s. -

1 1 heads and plucks, at Is.
10 ftone 4 lb. fat, at 3s. lOd. ~

Refpecting the goodnefs of the mutton, enquiry muft be made
of Mr. Giblet, at whofe mop the carcafes were (hewn for fe-
veral days, and of his cuftomers who purchafed the joints.
Experience has, however, demonftrated already, both at
Windfor and at Weybridge, that Spanifh mutton is of the beft
quality for a gentleman's table.
Sale of their pelt The pelt wool of thefe 1 1 fheep was taken off, in order that
its value might be afcertained.

It weighed in the yoke - - . - 36 lb.

Lofs in fcowering - - - - 8

Amount of fcowered wool 28

It was fold as fkin wool for 4-s. 6d. a pound, and of courfe
produced 51. 19s. or 10s. a fheep, all expences deducted.
The amount of this profit was quite unexpected, and holds
forth a fource of advantage in this breed, that has not probably
hitherto been calculated upon.
The commend- Of all who have laboured to render his majefty's patriotic
Drf Parry of ° v'ews m importing Spanifh fheep permanently ufeful to his
Bath, in ad- fubje&s, Dr. Parry of Bath deferves the higheft commendation,
yancing his ma- Amidft the labours of a profeffion always toilfome when fuc~

jetty s patriotic r J

views as to this cefsful, and particularly fo at Bath, where perfons, whofe dif-
.©bject. cafes cannot be afcertained by the faculty elfewhere, conti-

nually refort, the do6ior found leifure to employ himfelf in the
improvement of the Britifh fleece, by croffing various breeds
with Spanifh rams prefented by his majefty to the Marquis of
Bath, and to the Bath Agricultural Society.

The prizes the dodor has continually obtained from the ju-
dicious and refpectable body from whom he borrowed rams,
for cloths made of his own wool, in the midft of a manufac-
turing country and amongft abundance of able competitors,
prove to a demonftration, that he has brought the fleeces of
the mixed breed very nearly to the value of the original Spa-
nifh;

STATE OF HIS MAJESTY'S F1NE-WOOLED SPANISH SHKEF. $Q

nifh ; nor is this to be wondered at, when we recollect that
the effect of a mixture of breeds operates in the following pro-
portions.

The firft crofs of a new breed gives to the lamb half of the Rate of imelia*

mmmm»m u)~~a c/\ - j. ration of wool

ram s blood, or 50 per cent. ^ by the Spanifl|

The fecond gives - - - - - 75 ditto, crofs.

The third 87 f ditto.

The fourth - 93| ditto.

At which period it is fald, that if the ewes have been judi-
ciouflv felecled, the difference of wool between the original
frock and the mixed breed is fcarcely to be difcerned by the
moft able practitioners.

More need not be faid of the doctor's merit. His book,
which every man who wifhes to improve wool ought to read,
will give a more juft idea of the acutenefs of his difcrimination,
the diligence with which he purfued his purpofe, and the fuc-
cefs that finally attended his judicious management, than can
be ftated in the brief form of a report like this.

Much, however, as Dr. Parry deferves the gratitude of all I-.ordi Somer-
who honour the fleece, Lord Somerville's merit Hands at leaft an/judkious
as eminently confpicuous. Emulating the example of his fo- labours in efta-
vereign, his lordfhip, whofe juft difcrimination of the valueof£|fo focfc,Spa~
different breeds of flock is admitted by the mod experienced
agriculturifts, made a voyage to Portugal, for the fole purpofe
of felecling by his own judgment, from the beft flocks in Spain,
fuch fheep as joined in the greater!: degree the merit of a good
carcafe, to the fuperiority in wool which the Merino flocks
are allowed to poffefs.

His lordftiip fucceeded, and brought home, more than two
years ago, a flock of the firft quality, which will probably re-
pay with advantage the cofts of the undertaking, as fome of
his lordfhip's rams are faid to have been already fold for 100
guineas each.

As ten crops of wool have now been (horn from his majefty's His majefty's

Spaniih flock, and not a Angle fheep from Spain has been in- Jock has Prove4
,,..,. ° r r by ten years ex-

troduced into it during the whole of the ten years that have perience, that

produced them, and as the tenth crop afforded nearly five-fixths Spaniih wool

of prime wool and only one-fourteenth of fribbs, it is to be neratg jn tnis cli-

hoped that the deep-rooted prejudice which has for ages de- mate, and that

ceived the people of England into an opinion that Spaniih wool exJ^jt.

degenerates in this climate, will now be finally lodged in that

catalogue

70 DESCRIPTION OF A NEW PROCESS OF REFINING.

catalogue of vulgar errors, which the increafe of human know-
ledge daily enlarges. It is to be hoped alfo, that a bold afler-
tion hazarded here, that the mutton of Spanifh fine-wooled
fheep is coarfe, tough, and little better than carrion, will b«
contradicted by the evidence of Mr. Giblet and his cuftomers,
to the fatisfa&ion of thofe who have unwarily given credit
to it.

His majefty having been pleafed to permit the fale of fuch
fheep as can be fpared from the Spanifh flock to be continued,
the rams will be delivered at Windfor, and the ewes at Oat-
lands, in the latter end of Auguft. At, however, it has been
fuggefted to his majefty that the carcafes of the fheep are evi-
dently improved, and that the wool has rather gained than loft
in value, fix guineas will be in future the price of a ram, and
two that of an ewe. And as his majefty has been gracioufly
pleafed to continue to entruft the management of the flock to
Sir Jofeph Banks, all letters on the fubject of it, addrefled to
him in Soho Square, will be anfwered, and the utmoft endea-
vours ufed to confult the convenience of thofe who with to be-
come purchafers.

July, 1802. JOS. BANKS.

II.

Defcription of a New Procefs of Refining. By Cit. Darcet,

Nephew*.

Caufesofperfec- J[ HOUGH the pradice of an art is alone fufficient to bring
tion in the arts. |fc tQ perfeaion^ [t muft alfo be admitted, that the greater num-
ber of ufes to which its produ&s are applied, as well as the
greater number of manufactories wherein its proceflTes are
carried on, are the principal caufes of its arriving quickly at
that defirable point; in fad, if the manufactured articles be of
general utility, if the procelTes be generally followed, a com-
petition is produced, and every manufacturer endeavours to
be victorious in the conteft in which he is engaged : it is then
that individual intereft Amplifies the operations of art and brings
them to perfection, it fucceeds in affording at a lower price
produces of a fimilar kind, or in many cafes of a fort preferable

* From the Journal de Phyfique, Vendemaire, An. XI.

DESCRIPTION OF A NEW PROCESS OF REFINING. 7 \

to thofe obtained by the original proceffes, and it is thus that

we daily fee a multitude of the arts arrive at a great degree

of perfection. I might produce as examples, the art of the Inftances.

pin-makers, that of the needle-maker, &c. &c. but I mean at

prefent to confine myfelf to a new procefs for refining *, the

details of which will fufficiently illuftrate what I advance.

It is known in commerce, that articles of gold and lilver, Standard of

after long ufe upon a change of fafliion, or from other circum- metedPate

° o . uncertain,

fiances, are melted together without attending to any rule or

proportion but that which arifes from the variable courfe of

trade.

The ingots obtained in thefe operations raufl, therefore, at
firft, contain different proportions of gold and lilver, but they
muft at laft be united with thofe metals, which in conformity
to the law will require to be added, in order to their employ-
ment in the arts of the jeweller and the iilverfmith.

To bring thefe metallic compounds into circulation again, Method of
that is to fay, to qualify them to be reconverted into works of bnn§ing metal*
gold or lilver, they muii undergo an operation which reduces ftandard,
them to the ftandard prefcribed by law, there are two methods
of accomplifhing this end.

The firll and molt natural is that which points out theaddU
tion of the quantity of gold, lilver, or copper, necefTary to
rellore the fixed proportions of the alloy.

In the fecond all the metals are feparated from each other,
and after reducing them to the Irate of pure or limple bodies,
the alloy is formed according to the legal proportions, but the
firft of thefe procefles conftitutes part of the fecond, inafmuch
as it employs the fame materials as are purified by means of
this laft, which is ufed to feparate an alloy of gold, lilver, &c.

It is to this operation that the name of refining is given.

All the operations of refining are founded upon the peculiar Refining pro-
properties of thofe bodies on which the refiner is to work. The Perly fo called*
chief procefs is that which bears the name of parting; its bafis Partin2*
is the infolubility of gold in the nitric acid ; this acid, by dif-
folving the filver and copper, leaves the gold, which was al-
loyed with thefe metals, at the bottom of the velfel in which
the folution is carried on.

* I here fpeak of refining as an art, without reference to its con-
nection with the financial operations of the ftate.

This

72

,Gold not com-
pletely purified
by the ufual pro-
cefles of parting.

Antient pro-
files. ■

Quartation.

Fufion witb,
nitre.

Granulation.

Parting by nitric
acid.

DESCRIPTION OF A NEW PROCESS OF REFINING.

This is feen by a (ingle experiment; but practice foon Chows
that for this folution to take place, it muft be made upon an
alloy of one part gold with four parts filver, and that it will
be more perfecl the greater quantity of concentrated acid is
employed, or the higher the degree of heat which is applied
to the velTels. Thefe obfervations improve the art, but do not
bring it to that point which will enable us to obtain the gold
in its greateft purity, for this metal very rarely comes from the
crucible more pure than 998 or 999 in a thoufand.

In this ftate it was that I found the art at my entrance into
the national refinery, where being placed as it were in com-
petition with the refiners of commerce, I fought the means of
improving the procefles already known, and I now offer to
the arts, that which has conftantly fucceeded with me during
two years operations carried on in the laboratory of Cit. Dize.

I (hall begin with defcribing the old procefles of refining,
and afterwards explain the method which I have fubftituted in
their (lead.

The ingots received in commerce by the refiners are more
or lefs rich, and more or lefs mixed with the fine metals, but
their purity is generally between 850 and 950 thoufandth parts.
They mix thefe ingots and unite them by fufion, fo that the
alloy intended to be formed fhall contain four parts of filyer to
one of gold ; they pour thefe alloys out in grains, and add to
every five kilogrammes 500 grammes, to the amount of 650
grammes of nitrate of potafh of the fecond boiling *,

The mixture is then melted in crucibles, where it is fuffered
to cool in a mafs, and thefe mafles are again fufed and granur
lated, to multiply the furfaces of the alloy to be fubmitted to
the action of the nitric acid which is employed ip the parting.

To perform this operation, the refiner diftributes the grains
in pots of ftone-ware, and pours two parts of nitric acid of
30 degrees over one part of the alloy. He places thefe pots
in a fand-bath, in order to affift the aclion of nitric acid upon
the filver, by means of the heat. When the folution is ef-

* The intention of this operation is to oxidate the copper and the
other metals which are mixed with the gold and filver j and in fa£t,
by this fufion, which is called (poujfee) the purity of the mafs is
J?rought to about .378 : hence the quantity of acid neceflary for its
folution is much diminiftied.

fected,

DESCRIPTION OF A NEW PROCESS OF REFINING. 73

fected, he decants the nitrate of filver, and wafhes the gold
until the water from the warnings will no longer decompofe
muriate of foda.

The gold is not yet freed from all alloy, he therefore adds to
it fome nitric acid of the fame ftrength, and brings the mixture
to ebullition, he then decants the nitrate of filver, wafhes the
gold, and adding to it nitric acid of 40°, he replaces the veflfel
on the fand-bath. When it has been fufficiently boiled, he
feparates the gold from the acid, and wafhes it with great care,
dries it by a gentle heat, melts it and forms it into ingots, the
purity of which, as I have faid above, does not generally ex-
ceed .998, and is even often below .995, which is the limit
fixed by law. In the latter cafe, the refiner is obliged to pro-
ceed to a new quartation and a new parting ; his expencesare
then doubled and may be even trebled, if in the fecond ope-
ration, he does not furmount the inconveniencies which caufed
the firft to fail.

This is the department of refining which I have brought Improved pro-
neareft to perfection, as will be feen in the defcription of my
procefs.

I mix, as in the old operation, the ingots of commerce, in Quartation and
fuch a manner, that when they are melted together, the gold ^eTunlredS^
in the alloy fhall bear proportion of one to four parts of filver. part of nitre.
I melt the ingots thus prepared, and when the matter is very
liquid, I project thereon about 200 grammes of nitrate of potafli
for every 20 kilogrammes of the alloy. This fmall quantity
O.f faltpetre is fufficient, as I have remarked, to oxidate the
tin, which is always combined in greater or lefs quantity with
the ingots of commerce. It is effential to feparate this tin,
becaufe in the operation of parting it becomes oxidated and
mixed with the gold, and at the time of that metal being
melted, it may perhaps be partly reduced and render it harfh
and of lefs purity.

When the whole is in perfect fufion, I immediately granu- Granulation,
late and diftribute it, as in the former method, into pots.
There I add to it the fame quantity of nitrid acid of the fame
ftrength, following exactly the fame manipulations as thofe I Parting as
have defcribed above : in one word I obferve the antient pro-
cefs to the moment, when the gold, after having been well
warned, is put into the crucible : I collect the gold in this ftate The parted gold

into as fmall a veflel as poffible, and add to it as much fu!phu-?^/ft/.wi'*
'' * ™ Julpbuncacidi

ric

14* DESCRIPTION OF A NEW PROCESS OP REFINING.

ric of 66° as will cover its furface ; I increafe the temperature
of this acid by placing my veflH on a fand-bath, I raife it to
ebullition, and keep it in that ftate for about an hour ; I then

gndwajbcd. fuffer the whole to cool *, I decant the acid and wafli the gold
until the water from the warnings will not yield any more pre-

It is then pure, cipitate with muriatic acid or alkalies. Nothing then remains
but to dry this gold, which is in powder, and to reduce it into
ingots, which will constantly be of the purity of 1.000, or 24
carats.

Thefe are all the details neceflary to direct the performance
of the operation which I propofe : the following are the ad-
vantages which I believe is actually pofleffes.

Advantages of I make nopoujje, consequently I fave both charcoal and cru-

the new procefs. cibJes . j ^ am enabjed to perform the operation without

pounding the metal fo often, and have fewer warnings and
meltings : but the greateft advantage of this improvement is
the considerable diminution of the fire left in the fcoria? ; for
in the former method the great quantity of nitrate of potafh
that was added, promoted the oxidation f, or the extreme di-
vifionof a confiderable part, of the filver, which then remained
in the fcoriae with the oxide of copper, the potafti, &c. and
this wafte amounted, in each operation, to 2400 grammes on
filver of the purity of .350 to .400. ; and this filver remained,
without yielding any profit, frequently for feveral years ; that
is to fay, until the time when the refiner had a fufficient quan-
tity of wafhings to make it worth refining.

I have already afTerted that I conftantly obtain the gold in
its greateft purity, or at 1.000. which is known to be a great

* I muft alfo obferve that it is efTential to fuffer thefulphuric acid
boiled with the gold, to be completely cold before it is decanted,
without this precaution, as the ftone-ware veffels ufed in France are
not capable of withftanding the great degree of heat acquired by the
acid in boiling, there is much hazard of being wounded by the frac-
ture of the veffels, and the drops of acid which are fcattered in all
directions;

For greater fafety, the bottom of the vefTel may be covered with
fiilphuric acid of 66 degrees, and at the temperature of the at-
mofphere.

f I dare not yet affirm that the filver is in the ftate of the fcorae
of the poujfeei I wait the refult of feveral experiments which I have
undertaken on this fubjec"l in order to fix my opinion.

advantage

ON THE CONSTRUCTION OF THE HEAVENS. 75

advantage in commerce, but it is of ftill more benefit to the
refiner, by his operation being certain ; and he no longer runs
any rifque, if the calculations of his alloy have been accurately
made, of being ruined by unfuccefsful operations, and by the
neceflity of repeating two or three times a procefs of which
nothing can infure the fuccefs.

III.

Remarks on the Conftruclion of the Heavens. By William
Herschfl, LL. D. F. R. S, From the Fhibf. Tranj 'actions,
1802. p. 477*.

IT has hitherto been the chief employment of the phyfical Celeftial objects
aftronomer, to fearch for new celeftial obj eels, whatfoever be^nXffed^0
might be their nature or condition ; but our flock of materials cording to their
is now fo increafed, that we fliould begin to arrange them refPeftlve na-
more fcientifically. The claffification adopted in my catalogues,
is little more than an arrangement of the objects for the conve-
nience of the obferver, and may be compared to the difpofi-
tion of the books in a library, where the different fizes of the
volumes is often more confidered than their contents. . But
here, in dividing the different parts of which the fidereal hea-
vens are compofed into proper claffes, I fliall have to exa-
mine the nature of the various celeitial objects that have been
hitherto examined, in order to arrange them in a manner moll
conformable to their conftru&ion. This will bring on fome Introductory ob-
extenfive confiderations, which would be too long for the fervations«
compafs of a tingle paper; I (hall therefore now only give an
enumeration of the fpecies that offer themfelves already to our
view, and leave a particular examination of the feparate di-
visions, for fome early future occations.

In proceeding from the mod fimple to the more complex
arrangements, feveral methods, taken from the known laws of
gravitation, will be fuggefted, by which the various fyftems
under confideration may be maintained ; but here alfo we fliall
confine ourfelves to a general review of the fubject, as obfer-

* To this Paper is annexed " a catalogue of 500 new nebulae,
nebulous ftars. planetary nebulae, and clufters of liars," for which
the reader is referred to the Tran factions.

vation

76 ON THE CONSTRUCTION OF THE HEAVENS.

vation muft furnifli us nrft with the necefiary data, to eftablifh,
the application of any one of thefe methods on a proper foun-
dation.

ENUMERATION OF THE PARTS THAT ENTER INTO THE
CONSTRUCTION OF THE HEAVENS.

I. Of infulated Stars.
i. Infulated In beginning our propofed enumeration, it might be ex-

ftars» pe&ed that the folar fyftem would ftand foremoft in the lift ;

whereas, by treating of infulated ftars, we feem, as it were, to
overlook one of the great component parts of the univerfe.
of which the It will, however, foon appear that this very fvftem, magnifi-
fun is one. cent as ^ js^ can onjy ranyc as a fingie individual belonging to

the fpecies which we are going to contider.
They are too far By calling a ftar infulated, I do not mean to denote its being

afunder to be totally unconnected with all other ftars or fyftems ; for no one,
fenfibly affe&ed, * . . . . J ' .

by gravitation. Dy tne 'aws of gravitation, can be mtirely free from the in-
fluence of other celeftial bodies. But, when ftars are fituated
at fuch immenfe diftances from each other as our fun, Arcturus,
Capella, Lyra, Sirius, Canobus, Markab, Bellatrix, Menkar,
Shedir, Algorah, Propus, and numberlefs others probably are,
we may then look upon them as fufficiently out of the reach of
mutual attractions, to deferve the name of infulated ftars.
Illnftration : In order not to take this affertion for granted, without fome

faa u!d re-C exam'nat»on* ^et us admit, as is highly probable, that the whole
qu'ue 33 millions orbit of the earth's annual motion does not fubtend more than

of years to fall an ancrle of one fecond of a degree, when feen from Sirius. In
together j ° . . , . ,

confequence of this, it appears by computation, that our iun and

Sirius, if we fuppofe their manes to be equal, would not fall

even if there together in lefs than 33 millions of years, even though they

were no contrary were not impeded by many contrary attractions of other neigh-

attradtions. . . . r , ,„ ,, r , . t . /-

bounng mlulated ftars ; and that, confequently, with the at-

fiftance of the oppofite energies exerted by fuch furrounding
ftars, thefe two bodies may remain for millions of ages, in a
ftate almoft equal to undifturbed reft. A ftar thus fituated may
certainly deferve to be called infulated, fince it does not imme-
diately enter into connection with any neighbouring ftar ; and
it is therefore highly probable, that our fun is one of a great
number that are in fimilar circumftances. To this may be
added, that the ftars we confider as infulated are alfo fur-
rounded by a magnificent collection of innumerable ftars, called

the

ON THE CONSTRUCTION OF THE HEAVENS. 77

the milky-way, which mud occafion a very powerful balance
of oppofite attractions, to hold the intermediate ftars in a ftate
of reft. For, though our fun, and all the ftars we fee, may
truly be faid to be in the plane of the milky-way, yet I am now
convinced, by a long inflection and continued examination of
it, that the milky-way itfelf confifts of ftars very differently
fcattered from thofe which are immediately about us. But of
this, more will be faid on another occafion.

From the detached fitualion of infulated ftars, it appears that initiated ftara
they are capable of being the centres of extenfive planetary may ^f the cen-

f a /^r.t- i • r- r u- / ters of planetary

iy Items. Of this we have a convincing proof in our iun, which, fyftems.

according to our claffification, is one of thefe ftars. Now, as
we enjoy the advantage of being able to view the folar fyftem
in all its parts, by means of our telefcopes, and are therefore
fufficiently acquainted with it, there will be no occafion to enter
into a detail of its conftruclion.

The queftion will now arife, whether every infulated ftar be Probably they
a fun like ours, attended with planets, fatellites, and numerous are { ''
comets ? And here, as nothing appears againft the fuppofition,
we may from analogy admit the probability of it. But, were
we to extend this argument to other fidereal conftruclions, or,
ftill farther, to every ftar of the heavens, as has been done fre-
quently, I mould not only hefitate, but even think that, from
what will be faid of ftars which enter into complicated fidereal
fyftems, the contrary is far more likely to be the cafe; and but the compli-
that, probably, we can only look for folar fyftems among in- probably 'ncrt^
fulated ftars.

II. Of Binary fidereal Syjlems, or double Stars,

The next part in the conftruclion of the heavens, that offers2* Double ftars,
itfelf to our confideration, is the union of two ftars, that are
formed together into one fyftem, by the laws of attraction.

If a certain ftar fiiould be fituated at any, perhaps immenfe,
diftance behind another, and but very little deviating from the
line in which we fee the firft, we mould then have the ap-
pearance of a double ftar. But thefe ftars, being totally uncon-
nected, would not form a binary fyftem. If, on the contrary,
two ftars fhould really be fituated very near each other, and at
the fame time fo far infulated as not to be materially aftecledorftarsrev°Mnff
by the attractions of neighbouring ftars, they will then compofecenter
a feparate fyftem, and remain united by the bond of their own

mutual

78

Four cafes of
•rbits.

Tn thefe cafes
die center of
gravity is confi
derabiy remote
from the larger
ftar.

ON THE CONSTRUCTION OF THE HEAVENS.

mutual gravitation towards each other. This fhould be called
a real double ftar j and any two ftars that are thus mutually
connected, form the binary fidereal fyftem which we are now
to confider.

It is ea fy to prove, from the doctrine of gravitation, that two
ftars may be fo connected together as to perform circles, or
fimilar ellipfes, round their common centre of gravity. In this
cafe, they will always move in directions oppofite and parallel
to each other ; and their fyftem, if not deftroyed by fome fo-
reign caufe, will remain permanent.

Figure 1 (Plate V.) represents two equal ftars a and /;,
moving in one common circular orbit round the centre o, but
in the oppofite directions of at and b t. In Fig. 2. we have a
fimilar connection of the two ftars ab ; but, as they are of dif-
ferent magnitudes, or contain unequal quantities of matter,
they will move in circular orbits of different dimenfions round
their common center of gravity o. Fig. 3. reprefents equal,
and Fig. 4. unequal ftars, moving in fimilar elliptical orbits
round a common centre ; and, in all thefe cafes, the directions
of the tangents ttt in the places a b, where the ftars are, wiU
be oppofite and parallel, as will be more fully explained here-
after.

Thefe four orbits, fimpleas they are, open an extenfive field
for reflection, and, I may add, for calculation. They fhew, even
before we come to more complicated combinations, where the
fame will be confirmed, that there is an efTential difference
between the construction of folar and fidereal fyftems. In
each folar fyftem, we have a very ponderous attractive centre,
by which all the planets, fatellites, and comets are governed,
and kept in their orbits. Sidereal fyftems take a greater fcope :
the ftars of which they are compofed move round an empty-
centre, to which they are nevertheless as firmly bound as the
planets to their mafly one. It is however not neceflary here
to enlarge on diftinctions which will hereafter be ftrongly fup-
ported by fact.;, when clufters of ftars come to be considered.
I (hall only add, that in the fubordinate bodies of the folar
fyftem itfelf, we have already inftances, in miniature, as it may-
be called, of the principle whereby the laws of attraction are
applicable to the folution of the moft complicated phenomena
of the heavens, by means of revolutions round empty centres.
For, although both the earth and its moon are retained in their
4 orbits

ON THE CONSTRUCTION OF THE HEAVENS. 79

orbits by the fun, yet their mutual fubordinate fyftem is fueh>
that they perform fecondary monthly revolutions round a centre
without a body placed in it. The fame indeed, though under
very narrow limits, may be faid of the fun and each planet
itfelf.

That no infulated ftars, of nearly an equal lize and diftance, If inflated ftars
can appear double to us, may be proved thus. Let Arfturus and ^ f^*?J°r *
Lyra be the ftars: thefe, by the rule of infulation, which we Arfturus and
nrnft now fuppofe can only take place when their diftance from Lyra> they can~ .
each other is not lefs than that of Sirius from us, if very accu- motenefs from
rately placed, would be feen under an angle of 60 degrees from the eartft appear
each other, They really are at about 59°. Now, in order to
make thefe ftars appear to us near enough to come under the
denomination of a double ftar of the firft clafs, we fhould re-
move the earth from them at leaft 41253 times farther than
Sirius is from us. But the fpace-penetrating power of a 7-feet
reflector, by which my obfervations on double ftars have been
made, cannot intitle us to fee ftars at fuch an immenfe diftance ;
for, even the 40-feet telefcope, as has been (hewn *, can only
reach ftars of the 1342d magnitude. It follows, therefore, that becaufe they

thefe ftars could not remain vifible in a 7-feet refkaor, if they .wo?idL1b"ome

r r i 1 , • ^ t r , wvifible before

were io tar removed as to make their angular diftance lets than they were re-

about 24J minutes; nor could even the 40-feet telefcope, un-mote enough,
der the fame'circumftances of removal, fhew them, unlefs they
were to be feen at leaft 2| minutes afunder. Moreover, this
calculation is made on a fuppofition that the ftars of which a,
double ftar is compofed, might be as fmall as any that can
poffibly be perceived ; but if, on the contrary, they mould
ftill appear of a considerable lize, it will then be fo much the
more evident that fuch ftars cannot have any great real dif«.
tance, and that, confequently, infulated ftars cannot appear
double, if they are fituated at equal diftances from us. If,
however, their arrangement (hould be fuch as has been men-
tioned before, then, one of them being far behind the other,
an apparent double ftar may certainly be produced ; but here
the appearance of proximity would be deceptive ; and the ob-
ject fo circumftanced could not be claifed in the lift of binary
fyftems. However, as we muft grant, that in particular fitu-It is highly im-
ations ftars apparently double may be compofed of fuch as are^rs*f*'' Lthat tikZ

fhould confiftof

* See Phil. Tranf. for 1800, Parti, page 83. ftars confide-

infulated,rab)y afunder»

30 ON THE CONSTRUCTION Of THE HEAVENS.

infulated, it cannot be improper to confult calculation, in or-
der to fee whether it be likely that the 700 double ftars I have
given in two catalogues, as well as many more I have fince
collected, fliould be of that kind. Such an inquiry, though
not very material to our prefent purpofe, will hereafter be of
ufe to us, when we come to confider more complicated fyf-
tems. For, if it can be fhovvn that the odds are very much
againft the cafual production of double ftars, the fame argu-
ment will be ftill more forcible, when applied to treble, qua-
druple, or multiple compofitions.
Computation Let us take zz Aquarii, for an inftance of computation.

probability116 This ftar is admitted, by Flamfteed, De la Caille, Bradley,
that the remoter and Mayer, to be of the 4th magnitude. The two ftars that
ftar fliould be «comp0fe jt being equal in brightnefs, each of them may be

much larger than

the mean lize as fuppofed to thine with half the light of the whole luftre. This,

is reouiiite } according to our way of reckoning magnitudes *, would make
them 4m x \/ 2 = 5y m ; that is, of between the 6th and 5th
magnitude each. Now, the light we receive from a ftar be-
ing as the fquare of its diameter direclly, and as the fquare of
its diftance inverfely, if one of the ftars of zz Aquarii be farther
off than the ftars of between the 6th and 5th magnitude are
from us, it muft be fo much larger in diameter, in order to
give us an equal quantity of light. Let it be at the diftance
of the ftars of the 7 th maguitude; then its diameter will be to
the diameter of the ftar which is neareft to us as 7 to 5-f, and
its bulk as 1,885 to 1 ; which is almoft double that of the

and the much neareft ftar. Then, putting the number of ftars we call of

greater impro- between the 6th and 5th magnitude at 450, we (hall have 686
firjon of the C°f the 7 th magnitude to combine with them, fo that they may

two ftars fliould make up a double ftar of the firft clafs, that is to fay, that the

agree with the ^ ftars fiot be more than #, afunder> Tne furface 0f

phenomena. J , ,

the globe contains 34036131547 circular fpaces, each of 5' m

diameter ; fo that each of the 686 ftars will have 49615357 of
thefe circles in which it might be placed ; but, of all that num-
ber, a fingle one would only be the proper fituation in which
it could make up a double ftar with one of the 450 given ftars.
The odds are ^ut thefe odds, which are above 75f millions to one againft
many millions the compofition of zz Aquarii, are extremely increafed by oui

to one.

* The expreflions 2m, 3m, 4m, &c. ftand for ftars at the diftance
of 2, 3, 4, &c. times that of Sirius, fuppofed unity,

foregoing

ON THE CONSTRUCTION OP THE HEAVENS* $\

foregoing calculation of the required (ize of the ftar, which
tnuft contain nearly double the mafs allotted to other ftars of
the 7th magnitude; of which, therefore; none but this one
can be proper for making up the required double ftar. If the
ftars of the 8th and 9th magnitudes, of which there will be 896
and 1 134, mould be taken in, by way of increafing the chance
in favour of the fuppofed compofition of our double ftar, the
advantage intended to be obtained by the addition" of numbers,
will be completely counteracted by the requifite uncommon,
bulk of the ftar which is to ferve the purpofe ; for, one of
the 8th magnitude, ought to be mOre than 2 J times bigger
than the reft : and, if the compofition were made by a ftar of
the 9th magnitude, no lefs than four times the bulk of the
other ftar which is to enter the compofition of the double ftar
would anfwer the purpofe Of its required brightness. Hence
therefore it is evident, that cafual fituations Will not account
for the multiplied phenomena of double ftars, and that confe-
quentiy their exiftence muft be owing to the influence of forte
general law of nature; now, as the mutual gravitation of bo-
dies towards each other is quite fufficient to account for the
union of two ftars, we are authorifed to afcribe fuch combina-
tions to that principle;

It will not be necefiary to infill any further on arguments Aftualobferva-
drawn from calculation, as I (hall foon communicate a feries of tl0n ,n(|,catef a

revolution of

obfervations made on double ftars; whereby it will be feeh> double ftars
that many oftftem have actually changed their fituatio'n with regard round their cen-
to each other, in a progrejfive courfe, denoting a periodical revo-
lution round eaeh other ; arid that the motion of jbme of them is
direct, while that of others is retrograde. Should thefe obfer-
vations be found fufficiently conclufive, we may already have
their periodical times near enough to calculate, within a cer-
tain degree of approximation, the parallax and mutual diftance
of the ftars which compofe thefe fyftems, by meafuring their
orbits, which fubtend a vifible angle.

Before we leave the fubjec"l of binary fyftems, I mould re- The fun is not
mark, that it evidently appears, that our fun does not enter thus combined j

i- • i , n r » „ though our fyf-

mto a combination with any other ftar, to as to form one or tem is not abfo-
thefe fyftems with it. This could not take place without our lutelv at reft«
immediately perceiving it ; and, though we may have good
reafon to believe that oiir fyftem is not perfectly at reft, yet the
caufes of its proper motion are more probably to be afcribed to
Vol. V. — Junk, G fome

gg ON TfiE CONSTRUCTION O*' THE- HEAVENS.

fome perturbations arifing from the proper motion of neigh-*
bouring liars or fyftems, than (o be placed to the account of
a periodical revolution round fome imaginary diftant centre.

III. Of more complicated Jidereal Syftems, or treble, quadruplet
quintuple, and multiple Stars.

3. Complicated Thofe who have admitted our arguments for the exiftence of
fidcreal l fyftems : reai double liars, will eafily advance a ftep farther, and allow

or treble, qua- J r

druple, &c that three itars may be connected in one mutual fyftem of re-
ftars* ciprocal attraction. And, as we have from theory pointed out,

in figures 1, 2, 3, and 4-j how two liars may be maintained in
a binary fytiem, we mail here mew that three ftars may like-
wife be preferved in a permanent connection, by revolving in
proper orbits about a common centre of motion.
Obfervations In all cafes where ftars are fuppofed to move round an empty

and inferences centre, in equal periodical times, it may be proved that an
nature of the imaginary attractive force may be- fuppofed to be lodged in
poflible revolu- that centre, which increafes in a direct ratio of the difiances.
by an attractive ^or ^lnce> m different circles, by the law of centripetal forces,
force, directed the fquares of the periodical times are as the radii divided by
the central attractive forces, it follows, that when thefe perio-
dical times are equal, the forces will be as the radii. Hence
we conclude, that in any fyftem of bodies, where the attractive
forces of all the reft upon any one of them, when reduced to a
direction as coming from the empty centre, can be (hewn to
be in a direct ratio of the diftance oi' that body from the centre,
the fyftem may revolve together without perturbation, and re-
main permanently connected without a central body.

Hence may be proved, as has teen mentioned before, that
two ftars will move round a hypothetical centre of attraction.
For let it be fuppofed that the empty centre o, in Fig. 1 and 3,
is poifeiled of an attractive force, increafing in the direct ratio
of the difiances oa : ob. Then, ftnee here ao and bo are
equal, the hypothetical attractions will be equal, and the bo-
dies will revolve in equal times. That this agrees with the
general law of attraction, is proved thus. The real attraction

of b upon a is ; and that of a uoon b is JL. ; and, fince-

b zz a, it will be : : : ao ; bo; which was required.

abz ub'2- ^

* In

to a center.

ON THE CONSTRUCTION OE THE HEAVENS, §3

In Figures 2 and 4, when the flars a and b are unequal, and Observations
their diftances from o alfo unequal, let o a = ra, and ob z=.m ; refne&in? the
and let the mafs of matter in a = w, and inb =zn. Then the nature bf the

, pofiible revolu-

attra&ion of b on a = , will be to the attraction of a on b tions governed

# £4 by an attractive

force, directed
= — -, 2nn:mi which is again directiy as«o:5o. t0 a center.

1 proceed now to explain a combination of three bodies, Figure of orbits,
moving round a centre of hypothetical attraction. Fig. 5 con-
tains a tingle orbit, wherein three equal bodies a b c, placed

at equal diflances, may revolve permanently. For, the real

attraction of b on a will be exprefled by — ; but this, reduced i

abx

to the direction of, will be only ., ' -7A; for, the attraction

ab3

in the direction & a is to that in the direction by, parallel to a o,

b b .by
as^7a ^Tt" The attraction alfo of c on a is equal to that

of b on a; therefore the whole attraction on a, in a direction

towards o, will be exprefled by w ' I. In the fame manner

ab3

we prove, that the attraction of a and c on b, in the direction

h o, is «__J — £ ; and that of a and b on c, in the direction c o,
ab3

2 c b v

is — 1-^-. Hence, a b and c being equal, the attractions in
ab3

the directions ao b o and c o will alfo be equal ; and, confe-
quently, in the direcl: ratio of thefe diflances. Or rather, the
hypothetical attractions being equal, it proves that, in order to
revolve permanently, a b and c muft be equal to each other.

Inftead of moving in one circular orbit, the three flars may
revolve in three equal ellipfes, round their common centre of
gravity, as in Fig. 6. And here we mould remark, that this
centre of gravity will be (ituated in the common focus o, of the
three ellipfes ; and that the abfolute attraction towards that
focus, will vary in the inverfe ratio of the fquares of the dis-
tances of any one of the flars from that centre, while the rela-
tive attractions remain in the direcl: ratio of their feverai dif-
tances from the fame centre. This will be more fully ex-
plained, when we come to confider the motion of four flars.
. G 2 A very

84 ON THE CONSTRUCTION OF THE HEAVfiNfJ

A ftmight-lined -A very lingular ftraight-lincd orbit, if fo it may be called,
orbit or ofciih- mayaifo exift in the following manner. It' a and b, Fig. 7,
tory motion. J 6 ,

are two large equal ftars, which are connected together by

their mutual gravitation towards each other, and have fuch
projectile motions as would caufe them to move in a circular
orbit about their common center of gravity, then may a third
fmall ftar c, fituated in a line drawn through o, and at rectan-
gles to the plane defcribed by the ftars a b, fall freely from reft,
with a gradually acquired motion to o; then, palling through
the plane of the orbit of the two ftars, it will proceed, but with
a gradually retarded motion, to a fecond point of reft d; and,
in this manner, the ftar c may continue to ofcillate between e
and d, in a ftraight line, palling from c, through the centre o,
to d, and back again to c. ^

In order to fee the poffibility and permanency of this con-
nection the better, let o be the centre of gravity of the three
bodies, when the ofcillating body is at c ; then, fuppofing the
bodies a and b to be at that moment in the plane p I, and ad-
mitting m to reprefent a body equal in mafs to the two bodies
a bt o will be the common centre of gravity of m and c. Then,
by the force of attraction, the body c and the fictitious body wt
will meet in o ; that is to fay, the plane p /, of the bodies a b,
will now be at p' I'. The fictitious body m may then be con-
ceived to move on till it comes to n, while the body c goes to
d; or, which is the fame, the plane of the bodies a b will novr
be in the pofition p" i" , as much beyond the centre of gravity o,
as it was on the oppofite fide m. By this time, both the ficti-
tious body m, now at n, and the real body c, now at d, have loft
their motion in oppofite directions, and begin to approach to
their common centre of gravity o, in which they will meet a
fecond time. It is evident that the orbit of the two large ftars
will fuffer confiderable perturbations, not only in its plane, but
alfo in its curvature, which will not remain ftrictly circular ;
the conftruction of the fyftem, however, is fuch as to contain a
fuflicic-nt compenfation for every difturbing force, and will con-
fequently be in its nature permanent.

Iii order to add an ofcillating ftar, it is not neceflary that the
two large ftars (hOuld be fo fituated as to move in a circular
orbit, without the ofcillating ftar. In Fig. 8, the ftars a and b
may have fuch projectile forces given them as would caufe
tliem todefcribe equal ellipfes, of any degree of excentricity.

If

©N THE CONSTRUCTION OF THE HEAVENS. 85

If now the fmall ftar c be added, the perturbations will tin- obfervations
doubtedly affed not only the plane of the orbits of the flars, and '"^""j"
but alfo their figures, which will become irregular moveable "atp„re ^/the
ovals. The extent alfo of the ofcillations of the flar c will be poffible revolu*
affeaed ; and will fometimes exceed the limits c d, and feme- ^ a^Sfve
times fall fliort of them. All thefe varieties may eafily be de- force, directed
duced from what has been already faid, when Fig. 7 was con- *° a cent»r»
fidered. It is however very evident, that this fyftem alfo
mull be permanent j fince not only the centre of gravity o will
always be at reft, but a o, whatever may be the perturbations
arifing from the (ituation of c, will ftill remain equal to 6 o.

It mould be remarked, that the vibratory motion of the flar
c will differ much from a cometary orbit, even though the lat-
ter mould be compreffed into an evanefcent elliplis. For,
while the former extends itfelf over the diameter of a globe in
which it may be fuppofed to be infcribed, the hypothetical
attractive force being fuppofed to be placed in its centre, the
cometary orbit will only defcribe a radius of the fame globe,
on account of its requiring afolid attractive centre.

After what has been faid, \t will hardly be necefTary to add,
that with the affiflance of any proper one of the combinations
pointed out in the four laft figures, the appearance of every
treble flar may be completely explained ; efpecially when the
different inclinations of the orbits of the flars, to the line of
fight, are taken into confederation.

If we admit of treble flars, we can have no reafon to op?
pofe more complicated connexions j and, in order to form an
idea how the laws of gravitation may eafily fupport fuch fyU
terns, I have joined fome additional delineations. TV very
fliort explanation of them will be fufficient.

Fig. 9 (Plate VI.) reprefents four flars, abc and d, ar-
ranged in a line ; a being equal to bt and c equal to d. Then,
if a o = b o, and c o = do, the centre of gravity will be in o;
and, with a proper adjuflment of projectile forces, the four flars
will revolve in two circular orbits round their common centre.
By calculating in the manner already pointed out, it will be
found, that when, for inflance, ao = 1, co = 3, and c = 4
= 1, then the mafs of matter in a = b} will be required to be
equal to 1,3492. j

It is not neceffary that the projectile force of the four flars
fliould be fuch as will occafion them to revolve in circles. The

fy fleuv

g(J ON THE CONSTRUCTION OP THE HEAVENS.

Obfervations fyftem will be equally permanent when they defcribe fimilar
refpeahreAe e^ip^es about the common center of gravity, which will alio be
nature of the the common focus of the four ellipfes. In Fig. 10. the ftars
^governed" a b c d> evolving in ellipfes that are fimilar, will always de-
by an attra&ive fcribe, at the fame time, equal angles in each ellipfis about the
foTc ntie6led centre of hypothetical attra&ion ; and, when they are removed
from abed to a b' c' df, they will ftill be fituated in a ftraight
line, and at the fame proportionate diftances from each other as
before. By this it appears, as we have already obferved, that
the abfolute hypothetical force in the fituation a' b ' d d', com-
pared to what it was when the ftars were at a b c d, is inverfely
as the fquares of the diftances ; but that its comparative exer-
tion on the flars, in their prefent fituation, is ftill in a direct
ratio of their diftances from the centre o, juft as it was when
they were at abed; or, to exprefs the fame perhaps more
clearly, the force exerted on a', is to that which was exerted

11

on a as . ■ — ; •— z . But the force exerted on a is to

ao\ ao\

that exerted on c, in our prefent inftance, as a o = 1 to c o
= 3 ; and ftill remains in the fame ratio when the ftars are at
af and c ' ; for the exertion will here be likewife as a o =; 1
to c'o = 3.

Fig. 1 1 reprefents four ftars in one circular orbit ; and its
calculation is fo fimple, that, after what has been faid of Fig. 5,
I need only remark that the ftars may be of any fize, provided
iheir mattes of matter are equal to each other.

It is alfo evident, that the projectile motion of four equal
ftars is not confined to that particular adjuftment which will
make them revolve in a circle. It will be fufticient, in order
to produce a permanent fyftem, if the ftars abed, in Fig. 12,
are imprefled with fuch projectile forces as will make them
defcribe equal ellipfes round the common centre o. And, as
the fame method of calculation which has been explained with
Figs. 6 and 1 0 may here be ufed, it will not be neceflary to
enter into particulars.

Fig. 13 reprefents four ftars, placed fo that, with properly
adjufted projcclHe forces, they may revolve in equal times, and
in two different circles, round their common centre of gravity
*. If ao = bo = 4, co = do =z 5, and c = d = 1, then
will the mafs of matter in a = bt required for the purpofe, be

ON THE CONSTRUCTION OF THE HEAVENS. 87

1,5136. This arrangement, remarkable as it may appear, Ob/ervatlons

cannot be made in all fixations ; for inftance, if the ,diftance ^^^

ao =zbo were aflumcd equal to 1, that of co = do being 2, nature of the

it would be impoffible to find fuch quantities of matter in a P.ofliUe revo,u-
1 n . _ tions governed

and b as would unite the four ftars into one fyftem. by an attractive

As we have fhewn how the arrangement in Fig. 10. may be fo^> d reeled
derived from that of Fig. 9, fo it will equally appear, (hat four
ftars may revolve in difFerent but fimilar ellipfes round their
common centre, as in Fig. 14. For here the four (tars, when
placed at abed, are exactly in the fituation reprefented in
Fig. 13; but, on account of difFerent projeclile forces, they
revolve, not as before in concentric circles, but in fimilar el-
liptical orbiis.

Fig. 15 reprefents three ftars, a be, in the fituation of Fig. 5,
to which a fmall ofcillating ftar, d, is added. The addition of
fuch a liar to Fig. 1, has been fufficiently explained in Fig. 7 ;
and, what has been remarked there, may eafily be applied to
our prefent figure. As the fictitious body mt in Fig. 7, was
made to reprefent the ftars a and b} it will now ftand for the
three ftars a b and c. If we fuppofe thefe liars to be of an
equal magnitude in both figures, the centre of gravity o, of the
three liars, will not be fo far from m and n as in Fig. 7 ; and
the perturbations will be proportionally lelTened.

Fig. 16 gives the fituation of three Itars, a be, moviilg in
equal elliptical orbits about their common focus o, while the
ftar d performs ofcillations between d and e. What has been
faid in explaining Fig. 8, will be fufficient to fhew, that the
prefent arrangement is equally to be admitted among the con-
ftruclions of fidereal fyftems that may be permanent.

We have before remarked, that any appearance of treble
ftars might be explained, by admitting the combinations
pointed out in Figs. 5, 6, 7, and 8 ; and it muff be equally
obvious, that quadruple fyftems, under what fiiape foever they
may mow themfelves, whether in ftraight lines, fquares, tra-
pezia, or any other feemingly the moft irregular configurations,
will readily find a folution from one or other of the arrange-
ments of the eight lafl figures.

More numerous combinations of ftars may ftill fake place,
by admitting fimple and regular perturbations ; for then all
forts of erratic orbits of multiple flexures may have a perrrta-
nent exiftence. But, as it would lead me too far, to apply cal-
culation to them, I forbear entering upo* the fubjeel at prefent.

Before

8$ ON THE CONSTRUCTION OP THE HEAVENS,

The numcroui ,Before I proceed, it will be proper to remark, that it may
ShlSr^Mn in Poffibly occur t0 many, who are not much acquainted with the
the heavens arrangement of the numberlefs ftars of the heavens, that what

P[eIeHinatdir haS b<ien faid may a11 be mere "^(s furmife ; and that, poffi-
quifirions is not bly, there may not be the leaft occafion for any fuch fpecula-
mere furmife. tions upon the fubjed. To this, however, it may be anfwered,
that fuch combinations as I have mentioned, are not the inven-
tions of fancy : they have an actual exiitence; and, were it
neceflary, I could point them out by thoufands. There is not
a (ingle' night when, in pafling over the zones of the heavens
by fweeping, I do not meet with numerous collections of double,
treble, quadruple, quintuple, and multiple ftars, apparently
infulated from other groups, and probably joined in fome fmall
fidereal fyftem of their own. I do not imagine that I have
pointed out the a&ual manner in which they are held together;
but it will always be a defirable ftep towards information, if
the poffibility of fuch unions, in many different ways, can be
laid before us ; and, very probably, thofe who have more
leifure to confider the different combinations of central forces,
than a practical aftronomer can have, may eafily enlarge oh
what has been laid down in the foregoing paragraphs.

IV. Of clujlering Stars, and the Milky-way.

4. Cluttering From quadruple, quintuple, and multiple ftars, we are na-

ft«s and the ^ mH ^ t ■ a contfderation of the vaft colledions of fmall
milky way. J . ,

ftars that are profufely fcattered over the milky-way. On a

very flight examination, it will appear that this immenfe ftarry
aggregation is by no means uniform. The ftars of which it is
compofed are very unequally fcattered, and (how evident
marks of cluftering together into many feparate allotments.
By referring to fome one of thefe cluftering collections in the
heavens, what will be faid of them will be much better under-
stood, than if we were to treat of them merely in a general way.
Let us take the fpace between /Sand y Cygni for an example, in
which the ftars are cluftering with a kind of divifion between
them, Co that we may fuppofe them to be cluftering towards
two different regions, by a computation, founded on obferva-
tions which afcertain the number of ftars in different fields of
view, it appears that our fpace between ft and V, taking an
average breadth of about five degrees of it, contains more
than 331 thoufand ftars j and, admitting them to be cluftering

two

ON THE CONSTRUCTION OF THE HEAVENS, g9

two different ways, we have 1 65 thoufand for each cluttering
collection. Now, as a more particular account of the milky-
way will be the fubject of a feparate paper, I fhall only ob-
ferve, that the above-mentioned milky appearances deferve
the name of cluttering collections, as they are certainly brighter
about the middle, and fainter near their undefined borders.
For, in my fweeps of the heavens, it has been fully afcer-
tained, that the brightnefs of the milky-way arifes only from
ttars ; and that their compreffion increafes in proportion to the
brightnefs of the milky-way.

We may indeed partly afcribe the increafe, both of bright-
nefs and of apparent compreffion, to a greater depth of the
fpace which contains thefe ttars ; but this will equally tend to
fhew their cluttering condition : for, fince the increafe of
brightnefs is gradual, the fpace containing the cluttering ttars
mutt tend to a fpherical form, if the gradual increafe of bright-
nefs is to be explained by the fituation of the ttars.

,\ V. Of Groups of Stars.

From cluttering ttars there is but a fhort tranfition to groups 5. Groups of
of ttars ; they are, however, fufficiently diftinct to deferve a s*
leparate notice. A group is a collection of clofely, and almoft
equally comprefled ttars, of any figure or outline ; it contain s
no particular condenfation that might point out the feat of an
hypothetical central force ; and is fufficiently feparated from
neighbouring ttars to (hew that it makes a peculiar fyftem of
its own. It mutt be remembered, that its being a feparate
fyftem does not exclude it from the action or influence of other
fyftems. We are to underftand this with the fame referve
that has been pointed out, when we explained what we called
infulated ttars.

The conftruction of groups of ttars is perhaps, of all the ob-
jects in the heavens, the raoft difficult to explain ; much lefs
can we now enter into a detail of the numerous obfervations I
have already made upon this fubject. I therefore proceed m
my enumeration.

VI. Of Clujlers of Stars.

Thefe are certainly the moft magnificent objects that can 6. Clutters of
be feen in the heavens. They are totally different from mere ftar**
groups of ttars, in their beautiful and artificial arrangement :

their

£Q ON THE CONSTRUCTION OF THE HEAVENS,

Jheir form is generally round ; and the compreffion of the ftars
ilievvs a gradual, and pretty fudden accumulation towards the
centre, where, aided by the depth of the clutter, which we can
have no doubt is of a globular form, the condenfation is fuch,
that the ftars are fufficiently comprefled to produce a mottled
luftre, nearly amounting to the femblance of a nucleus. A
centre of attraction is fo ft rongly indicated, by all the circum-
ftances of the appearance of the clufter, that we cannot doubt
a (ingle moment of its exiftence, either in a ftate of real foli-
dity, or in that of an empty centre, podelled of an hypotheti-
cal force, arifing from the joint exertion of the numerous ftars
that enter into the compolition of the duller.

The number of obfervations I have to give relating to this
article, in which my telefcopes, efpecially thofe of highfpace-
penetrating power, have been of the greateft fervice, of courfe
can find no room in this enumeration.

VII. Of Nebulae.

7. Nebula. Thefe curious objects, which, on account of their great dif7

tance, can only be feen by inltruments of great fpace-pene-
trating power, are perhaps all to be refolved into the three
laft mentioned fpecies. Cluttering collections. of' ftars, for in-
stance, may eafily be fuppoi'ed fur.iciendy removed to prefent
us with the appearance of a nebula of any fhape, which, like
the real object of which it is the miniature, wiil feem to*be gra-
dually brighter in the middle. Groups of ilars alfo may, by
diftance, alTume the femblance of nebulous patches ; and real
clutters of ftars, for the fame reafon, when their coinpofition
is beyond the reach of our molt powerful inftruments to refolve
them, will appear like round nebulcc that are gradually much
brighter in the middle. On this occafion I mult remark, that
with inltruments of high fpace-penetrating powers, fuch as my
40-feet telefcope, nebula? are the objects that may be per-
ceived at the greateft diftance. Cluttering collections of ftars,
much lefs than thofe we have mentioned before, may eafily
contain 50,000 of them ; and, as that number has been chofen
for an inftance of calculating the diftance at which one of the
moft remote objects might be ftill vifible*, 1 fliall take notice
of an evident confequence attending the refult of the compu-

* See Phil. Tranf. for 1800, page 83. N. B In the fame page,
line 22, for 5000 read 50,000.

3 tation ;

ON THE CONSTRUCTION OF THK HEAVENS. 91

tation ; which is, that a telefcope with a power of penetrating

into fpace, like my 40-feet one, has alfo, as it may be called,

a power of penetrating into time paft. To explain this, we [™™f*™*'

mufi: conlider that, from the known velocity of light, it may heavens, or fpacs

be proved, that when we look at Sirius, the rays which enter containing ita.s.

the eye cannot have been lefs than fix years and 4| months

coming from that ftar to the obferver. Hence it follows, that Light employing

o lix yea.s jii its

when we fee an object of the calculated diftance at which one paflage from S\-
of thefe very remote nebulae may Hill be perceived, the rays "»>s 3 ana near

J ... rii. tvvo mu ions or

of light which convey its- image to the eye, mult have been >ear3 in amvijJg
more than nineteen hundred and ten thoufand, that is* almoft from remote
two millions of years on their way;, and that, confequently, fo "L^,lilUjjT'
many years ago, this object mult already have had an exigence have exited {t
in the fidereal heavens, in order to fend out thofe rays by bnS ao°*
which we now perceive it.

VIII. Of Stars with Burs, or Slcller Nebula.
Situated as we are, at an immenfe diftance from the remote 3- Stellar ne-
parts of the heavens, it is not in the power of telefcopes to re-
folve many phenomena we can but juft perceive, which, could
we have a nearer view of them, might probably (hew ihem-
felves as objects that have long been known to us. A ftellar
nebula, perhaps, may be a real clufter of ftars, the whole light
of which is gathered fo nearly into one point, as to leave but
jufr. enough of the light of the clufter vifible to produce the
appearance of burs. This, however, admits of a doubt.

IX. Of milky Nebulofity.

The phenomenon of milky nebulofity is certainly of a molt 9*.M'% neiu-
interefting nature : it is probably of two different kinds ; one
of them being deceptive, namely, fuch as arifes from widely .
extended regions of clofely connected cluftering ftars, conti-
guous to each other, like the collections that conftruct our
milky-way. The other, on the contrary, being real, and pof-
ftbly at no very great diftance from us. The changes I have
obferved in the great milky nebulofity of Orion, %o years ago,
and which have alfo been noticed by other aftronomers, can-
not permit us to look upon this phenomenon as arifing from
immenfely diftant regions of fixed ftars. Even Huygens, the
difcoverer of it, was already of opinion that, in viewing it, we

faw,

9*2

to. Nebulous

ifcars.

jz. Planetary

nebulae.

ON THE CONSTRUCTION OP THE HEAVENS.

faw, as it were, through an opening into a region of light*.
Much more would he be convinced now, when changes in its
fhapeand luftre have been feen, that its light is not, like that
of the milky-way, compofed of ftars. To attempt even a guefs
at what this light may be, would be prefumptuous. If it
fhould be furmifed, for inftancq, that this nebulofity is of the
nature of the zodiacal light, we mould then be obliged to ad-
mit the exiftence of an effect without its caufe. An idea of
its phofphorical condition, is not more philofophical, unlefs we
could fhew from what fource of phofphorical matter, fuch im-
meafurable traces of luminous phenomena could draw their
exiftence, and permanency ; for, though minute changes have
been obferved, yet a general refemblance, allowing for the
difference of telefcopes, is ftill to be perceived in the great
nebulofity of Orion, even fince the time of its firft difcovery.

X. Of Nebulous Stars.

The nature of thefe remarkable objects is enveloped in much
obfcurity. It will probably require ages of obfervations, before
we can be enabled to form a proper eflimate of their condi-
tion. That ftars fhould have vifible atmofpheres, of fuch an
extent as thofe of wjiich I have given the fituation in this and
my former catalogues, is truly furprifing, unlefs we attribute
to fuch atmofpheres, the quality of felf-luminous milky nebulo-
fity. We can have no reafon to doubt of the ftarry nature of
the central point ; for, in no refpedt whatever does its appear-
ance differ from that of a ftar of an equal magnitude ; but,
when the great diflance of fuch ftars is taken into considera-
tion, the real extent of the furrounding nebulofity is truly
wonderful. A very curious one of this kind will be found in
the 4th clafs, No. 69.

XI. Planetary Nebula.

Thisfeems to be a fpecies of bodies that demands a particu-
lar attention. To inveftigate the planetary nature of thefe
nebulce, is not an eafy undertaking. If we admit them to con-
tain a great mafs of matter, fuch as that of which our fun is
compofed, and that they are, like the fun, furrounded by denfe
luminous clouds, it appears evidently that the intrinfic bright-
wfc of thefe clouds mull be far inferior to thofe of the fun, A

* See Syjle?na Saturnium, page 8 and 9,

part

OF A NEW STATICAL LAMP. <)$

j>art of the fan's difk, equal to a circle of 15" in diameter,
would far exceed the greatefl luflre of the full moon ; whereas,
the light of a planetary nebula, of an equal fize, is hardly
equal to that of a ftar of the 8th or 9th magnitude. If, on
the other hand, we fliould fuppofe them to be groups, or cluf-
ters of liars, at a diflanee fufficiently great to reduce them to
fo fmall an apparent diameter, we fhall be at a lofs to account
for their uniform light, if clufters; or for their circular forms,
if mere groups of liars.

. Perhaps they may be rather allied to nebulous liars. For,
fliould the planetary nebulae with lucid centres, of which the
next article will give an account, be an intermediate flep be-
tween planetary nebulce and nebulous liars, the appearances of
thefe different fpecies, when all the individuals of them are
fully examined, might throw a conliderabie light upon the
fubjec"t.

XII. Of planetary Nebulce with Centres.
In my fecond catalogue of nebula, a tingle inftance of a n. Planetary
planetary nebula with a bright central point was mentioned j nebul* Wltii
and, in No. 73 of the 4th clafs, is another of very nearly the
fame diameter, which has alfo a lucid, though not quite fo
regular a centre. From feveral particularities obferved in
their conftruction, it would feem as if they were related to
nebulous flars. If we might fuppofe that a gradual condenfa-
tion of the nebulofity about a nebulous liar could take place,
this would be one of them, in a very advanced flate of com-
preffion. A further difcuffion of this point, however, mull
be referved to a future opportunity.

IV.

Defcription of a New Statical Lamp, zvhich of itfelf raifesmid
keeps the Oil at a conftant Height. By M. D'Edelcrantz,
of Stockholm, Member of feveral Academies and Literary So-
cieties, Knight of the Order of the Polar Star, %c *.

OINCE the firft invention of the lamp with a double current Advantages of
of air by M. Argand, many attempts have been made to find Placil?S *c fe"

iL r i • *i_ r • r -i ii , r , fervoir of a lamp

the means of placing the refervoir of oil below the focket of below the flame*

* Communicated by the Author.

the

94* OP A NEW STATICAL IAM1*.

the lamp, and to raife if, in order riot only to prevent the

difagreeable fliadovv of lamps on the ordinary construction,

which always produces darknefs in fome part of the apartment,

but alfo to alter the contraction, and afford the manufacturing

arlift an opportunity of giving it thofe elegant forms of which

the inftrument is capable.

A new lamp I fiiall not (peak of * Keir's hydroftatic lamp, nor of that

thofe of Kier w'tn wheel-work by f Carcel, as they are both well known,

and of Carcel. but confine myfelf to the defcription of this new lamp, and

which I have confidered with the fame defign as thefe philo-

fophers.

Bcfcri -tion with The body of the lamp, Fig. I, confifts of three veffels,

draw-in* C Aalih, dehh, and bbfg. Thefe may be either cylindrical or

rectangular, and made of (beet iron, they differ little in height,

Defcripthn of a and about a line in their diameters, the veffels aahh, and

■Bwftatica dehh, are joined at their lower edges h h ; — dehh is clofed

at de; and aahh is -terminated at a a, by a fmall gallery or

balu tirade by way of ornament. The third veffel bbfg, which

pafles eafily between tjie other two, is alfo clofed at/g, by a

plate which projects about three lines ; from the center of this

there rifes a tube kkll, "to the extremity // of which is fcrewed

the focket of a common Argand's lamp. In the center of this

is fixed another tube pq, made of tin, in which the iron wire

win is placed, and is befides fixed to the plate de, at right

angles to its furface, the end of the wire is furnifhed with a

nut and fcrew o o. This wire fcrews to direct the veffel bbfg

in its motion between the two others, and the pofition of the

nut is intended to determine the limits of that motion.

To ufe this lamp, let us fuppofe the nut o o to be fo fixed,
that when the vefTei bbfg is at itsgreateff. height, there fhall
only remain a fpace of 14- or 15 lines between the two other
veilels, that is to fay, a length equal to d b. Now pour mer-
cury into the fpace between the two veffels to within the dif-
tance of a few lines at de, as to rr ; the edge of the middle
veflel will then be immerfed in mercury, and all communica-
tion between the infide of this veffel and the outer air will be
cut off. And if after having unferewed the focket of the lamp,
oil be poured into the inftrument by the aperture 1 1, it will

* Phil of. Journal, Quarto, III. 467.
f Philof. journal, New Series, II. 108.

occupy

OP A NEW STATICAL LAMP. 9j

occupy the fpace between the two ends fg and de, and the Defection of a
oil by preffing on the furface of the mercury at rr, will raife ™" ftat,wl
it a little on the outfide from its height and fpecific gravity.
The fpeciric gravity of oil to that of mercury is about as one
to 16, a column of oi-1 therefore of 16 inches would not raife
the mercury above an inch *.

If, after having filled the refervoir with oil, and fcrewed on
the focket, the Plate fg be fo adjufted with weights, that it
(hall become equal in weight to a column of oil whofe bafe is
fg, and height ks ; it is evident that the oil in the refervoir
will under this preflure rife to s s, and will conftantly remain
at that height while any remains, and while the weight of fg
continues unaltered, notwithstanding the fall of fg, which
when the oil is confumed, will be deprefled to de, and refl
on the Plate de. uutt, is a fmall tin tube, intended to re-
ceive the oil which may be fpilled ; it anfwers the* purpofe
of the fmall round glafs ufually hung beneath other lamps.

The height to which the oil may be raifed in a lamp of this
kind is arbitrary, fince to increafe the height of the focket it
is only neceflary to increafe the weight in proportion, always
providing a fpace for the rife of the mercury, equal to a 16th
part of the rife of the oil. This rife will be conftant, the
weight being always the fame/ as it does not in any refpeel
depend on the quantity of oil in the refervoir.

It is neceflary, however, to obferve refpe6ting the inva-
riability of the counterpoifing weight, that it will not be geo-
metrically accurate. We know by the laws of hydroftatics,
that a folid body lofes by immerfion in any fluid as much of its
weight as is equal to the weight of the fluid difplaced by it;
now as the oil is confumed, the middle veflel finks deeper into
the mercury, and confequently lofes of its weight, it will
therefore after fome time be evidently incapable of fupporting
the column of oil at the fame height as before. But if this
middle veflel be made of very th'in fheet iron and has not much
range, this diminution will be inconfiderable, and may in prac-
tice be entirely neglected. The lamp in the figure being ad-
jufted to 10 lines, will contain oil fufficient for eight hours, at
the end of this time, the furface of the oil in the focket will

* L e. Half an inch rife without and half an inch depreflion
within. N.

have

96 OF A NEW STATICAL LAM!1.

Defcrlptlon of a have fallen but two or three lines, whilfl the flame will not b4
new^ftatical materially injured by a fall of four or five. By admitting a
larger interval between de and fg, the lamp will hold more
oil and burn longer. To raife the oil to its proper height on
thefe occafions, it will be necefTary to add more weights ; for
example, one ounce for each line of the height required.

The method of filling and ufing the lamp will naturally be
underflood from the foregoing defcription. I (hall only add,
that the quantity of mercury required will be about a pound,
and that when once put into the lamp it need not be removed
from thence, unlefs it mould be thought proper to clean the
infide of the lamp at intervals. lathis cafe the oil and mer-
cury may be poured together into a glafs or earthen veilel, and
the mercury afterwards feparated from the oil by a paper
ilrainer. The inflrument may be cleaned with warm water
and a feather, it may then be filled again, and when the proper
weights are placed, the rife of the oil mufl be produced by a
gentle fhaking of the lamp, any unufual prefiure for this pur-
pofe mufl be avoided. The oil will not rife to its proper and
conftant height till a few moments after being lighted. The
length of the lower current of air requires high chimneys to
produce a clear light. Thefe mufl be taken off when the
lamp is extinguished. To remove it with fafety, the column
or upper part of it mufl be taken off, and the inflrument be
carried carefully by its focket.

It will eafily appear, that various ornamental and elegant
forms may be given to this lamp, the determination of which
will remain with the manufacturing artifl. Our prefent defign
reprefents a truncated column, on a fquare bafe, ornamented
with four balls, which alfo ferve for the counterpoifing
weights.

I have thought proper to call this inflrument a flatical lamp,
as depending on the equilibrium of three different bodies,
two of them fluid, and one folid.

Pa

ON OILY HIDROGEN. §7

On Oily Hidrogen. By Profejfor Proust *.

I HE perufal of the memoir of the Dutch chemifts having Gas by diftilla-
fuggefted to me the idea of making two experiments on the
gas obtained by the diftillation of olive-oil, I apprehend, doc-
tor, that you will fee the refult with pleafure. With refpect
to the inferences which I have ventured to draw from them,
if they be not true, they will neverthelefs contribute to extend
the fcale of this new order of fa&s, and increafe the means of
fmdying them with better effect.

I call this gas oily, becaufe it feems to me that its great Called oily gas,'
weight ; its white, footy, heavy flame ; its ftrong fmell ; and
above all, its property of becoming lighter by being pafled
feveral times over alcohol, point out a fimple folution of the
oily vapour in carbonated hidrogen.

The pureft oil rauft yield a considerable quantity of carbonic Pure oils yielfi
acid with the oily gas. Berthollet was perfectly right in faying ^°^ce ^
that a certain dofe of oxigen would be found in the oils : be- gas:
fides, the abforption which they continually make authorifes they contain
it. It may perhaps be attempted to conned this acid with the oxlSen#
principles of that mucous body which Scheele feparated from
them by oxide of lead j but if on the one hand, the nature of
the ingredients in this operation be well considered, and on
the other, that of the fugar of oils, I believe it will not be Sugar of oils$
unreafonable to fuppofe that the fugar was entirely formed
during their co&ion with the oxide.

It is free from every metallic matter, iince it does not render not the fame as
hidro-fulphurated water turbid ; but it is particularly diftin- fugars#
guifhable from all our vegetable fugars, becaufe it is not fuf-
ceptible of any fermentation, corruption or mouldinefs. I Its unchange-
have kept three or four ounces of it full ten years, which is of a e na ure\
the confidence of a tolerably clear fyrup, without its having
experienced the flighted alteration in the greatefr. heats. In
a word> I am very much difpofed to believe that this fpecies
of fugar is rather a new product than a fubftance feparated
from the oils.

* From the Journal de Phyfique, Germinal, An. XI.
Vol. V.— June H Diftilled

98 °N OILY HIDROGEN.

Diftilled oil again difcovers characters to which little atten-
tion has been given. It is changed into a volatile odorous or
eflential oil, doubtlefs by diiTblving a certain quantity of car-
bonated hidrogen. The following are fome of its properties :
Properties of When heated with water in a retort, part of it comes over

dialed oil. in the diftillation. It has a very powerful but difagreeable
fmell, with a degree of lightnefs which places it in the rank
of volatile oils, becaufe its weight to that of olive-oil is not
more than as 91 to 100. It fwims upon alcohol, which dif-
folves it with eafe. Laftly, it enters into ebullition as readily
as fpirit of turpentine ; and if a lighted taper be brought to
the mouth of the matrafs, the vapour of it burns like that of
volatile oil.

I have not particularly examined the acid liquor which ac-
companies the diftilled oil : I (hall only infert a fact relative to
Scbate of potato its hiftory. If foap be diftilled to the deftruction of its oil,

remains after the t]]e fal;ne refic]ue wnicn J fll0u](J nave expeded to be the
diftillation of * .

foap. carbonate, is found to be the febate of potafh. It is cryltal-

lizable, and the fulphuric acid inftantly difengages that pene-
trating vapour called febacic acid. But to return to the oily
hidrogen, which holds in folution the factitious eflPeniiai oil
which I have mentioned at the beginning. When the heat
fuddenly ftrikes that portion of the oil which is found there,
as if in a red hot tube, it pafles from the vapourous flate to
that of carbonated hidrogen, in the fame way as happens to
ether, alcohol, radical vinegar, eflence of turpentine, &c.
when they pals through a red-hot tube.

I fhall conclude this by an experiment which Rouelle made
in his lectures, and which I alfo fhow in mine ; becaufe in ad-
dition to the agreeable fpectacle, the explanation of its caufes
is perfectly conformable to the theory of inflammations.

Beautiful ap- Pour half a fpoonful of olive-oil into a fmall melting cruci-

pearance from ^Ie obfeurely red, or at that degree of heat which (hall have
the furfden com- , ..„ J . . r . ° . . . . . , ,

.bullion of oil ; been dilcovered by tome previous experiments. A thick cloud

of white fmoke will immediately rife which takes fire at its
fummit, that is to fay, four or five feet diftant from the cru-
cible. If on the contrary, the combuftion of the cloud arifes
from the crucible, it is occasioned by the heat being too great.
In that cafe we mutt wait a few minutes, and the phenomenon
and wax. W»H appear in all its magnificence. A piece of wax will give

the fame effects, but it feems to me to require more previous
preparations than the oil.

On

ON dlLY HIDROGEN. QQ

On the Difoxidation of Iron.

The fimpleft truths of chemiftry are not always thofe which The, <imPleft
' J J truths of che-

are the molt eafily mown in public teaching. For example, m]({Ty notal-

nothing can be more evident to the mod numerous auditory ws»ys eafy to be
., L . ,. . . , . •"'•»*.-•*■ manifefted in a

than that, m the tube experiment, the iron carries with it an ieaure,

overcharge of oxigen, becaufe every one of the fpeclators can
fatisfy him felf by his eyes, and acquire an abfolute conviction
of that which is intended to be mown ; but when amidft the Instance. Dif-
connexion of ideas and proofs, we come to thofe which relate oxidationofiron
to the difoxidation of this metal, we mull quit facls and re-
place them by fuppoiitions, becaufe it is not poffible to exe-
cute them with facility in public. In fadt, it is impoffible
either to apply a degree of heat in a few inflants to the oxide
of iron, fumcient to deoxidate it, nor can it even be eafily
reduced by melting. But by the following procefs this diffi-
culty is partly overcome.

Heat for an hour a mixture of one ounce of iron ore of Eafy procefs for
Eiba, and two gros of charcoal, in a fmall coated glafs retort, <his 'deoxidatioa
at the bottom of which the clay has been left of the thicknefs . re*h t ,
of two inches. Place it immediately on the grate of the fur- in a glafs retort
nace, and its neck will then projeft from the furnace by the wich chaicoal*
door of the fire-place. Clofe it with fragments of bricks and
earth, which will keep the retort in its fituation. If the neck
be not long enough to reach into the pneumatic-trough, which
,in this cafe ought to be a fallad-difti or a foup-plate covered
with a plate of lead perforated, add to it another which muft
be luted with paper and ftarch.

Having done this, cover with the ufual precautions> the
grate and the retort with charcoal. It receives from this dif-
pofition a much more intenfe heat than if it had been placed
on the bars. The carbonic acid and carbonated oxide are
then obtained with the greateft facility.

When the retort is cold, its belly will be found to be nearly State of the
filled with pure iron of a fpongy appearance^ which acquires reducediroa*
the metallic brilliancy by friction with any polifhed fubftance.
This mafs is broken with difficulty, and notwithstanding the
feparation of its parts, they will be all found to be foldered
together. On heating it dexteroufly by the blow-pipe, it burns
with fparkling. The magnet attracts the whole of it. Part
of it may be ufed to give hidrogen with fulphuric acid, in

H 2 fhort

100

Bituminous
odour from its •
folution.

The proccfs with
coal of blood,

gives ammo-
niacal gas.

Inflammation.

with oxigcn ;

9ttended with,
cxpanfion.

ON OtLY HIDROGEtf.

fhort every ene is convinced on touching it, that it is iron re-*
duced to its primitive ftate, and that if it were formed into a
raafs, it might conftitute bar-iron.

As carburet is formed in this operation, the diflblution of
the iron yields the fame bituminous fmell as that which is
obferved in crude iron.

If inftead of wood-charcoal, that of blood well wafhed be
mixed with the oxide, ammoniacal carbonate will be depofited
in the neck of the retort. I have explained the caufe of this
product in my fecond memoir on Pruffian blue. The folution
of iron then affords phofphate with the potafh at the firft mo-
ment of its precipitation. The bituminous odour of the folu-
tion of caft. iron as well as the gas, are alfo obtained from re*
cently made charcoal of blood, by the application of fulphuric
acid, it takes fire at the mouth of the matrafs. The reafon of
this is fo evident, that it would be fuperfluous to dwell on it.

Four inches of this gas, and one of oxigen, cannot be in-
flamed in a tube with the charge of a pocket electrophorus ;
neither can it with two of oxigen, nor even with three. My
object in thefe experiments was to difcover if charcoal or oil
would be precipitated.

Laftly, with four inches of oxigen or equal parts an inflam-
mation takes place ; but it caufes an agreeable furprife to ob-
ferve that, on opening the ftop-cock, the gazeous refidue in-
ftead of being diminifhed, is on the contrary, increafed to
thirteen or fourteen inches. This fudden expanfion is accom-
panied by another fa6l equally curious, the explanation of
which is obvious, on recollecting the obfervation of Monge,
on an atmofphere more or lefs compreffed. This is a cloud or
thick mift which fills the tube as the refidue efcapes from its
former compreflion. Let us now examine our eight inches of
mixture which has increafed in bulk to thirteen or fourteen by
the inflammation.

On transferring it through lime-water, it will be found that
it fcarcely troubles it, and even at fometimes not perceptibly
at all. It alfo, within a few lines, prefer ves its dimenlion*
of thirteen or fourteen inches.

If a light be prefented to it, it will be feen that it is not
oily hidrogen. Its blue flame defcends flowly, and it is con-
fumed without the leaft detonation.. Laftly, it has but a weak
odour very different from that of oily hidrogen.

This

ON OILY HIDROGEN. 101

This gas burnt with oxigen is wholly converted into car- The expanded
bonic acid, and is no longer dilatable however fmall the quan- ^bJ^^,jJ
tity of oxigen mixed with it may be. when burned

The following are the conjectures which I form at prefentwith 0X1Sen«
from thefe refults.

I do not think that the refidue retains the lead trace of oxi-
gen after the inflammation, otherwife it would bum with rapi-
dity, which is far from being the cafe.

Four inches of oxigen generally confume feven and a half Conjectures or
of pure hidrogen in my eudiometer, and as our refiduary gasln erences*
contains only a very fmall quantity of carbonic acid, it follows,
that thefe four inches have confumed a quantity of hidrogen
which would have been at leaft equal to feven inches, had it
been in the ufual Hate of dilatation at which the preiTure of
the atmofphere keeps it.

Four inches of oily hidrogen therefore contain, according
to this, feven inches of pure hidrogen condenfed into the bulk
of four.

Again our refidue after the combuftion of four inches of
oily gas, is all at once changed into thirteen or fourteen inches
of carbonated hidrogen. We muft therefore conclude, that
the feven inches of hidrogen comprefled into the bulk of four,
held in folution a quantity of oil capable of being converted,
by a high temperature, into thirteen or fourteen inches of car-
bonated hidrogen.

I fay a high temperature, becaufe in fact, that alone is ca-
pable of changing oil into carbonated hidrogen.

Whence I conclude, that in the inflammation of four parts
of oily gas, by an equal quantity of oxigen, nothing is really
burnt but the hidrogen.

VI.

Letter from Fortis to J. G. Delametherie, on a Shower
of Mud which fell at Udina *.

JL HAVE juft received at the fame time, the number of the
Journal de Phyfique, in which you notice the different opi-
nions refpecYmg flones fallen from above, of which almoft every

* In the Journal de Phyfique, Germinal, An. XI.

country

102

Muddy ihower
which extended
over feveral
league..

Its probable
nature.

ON A SHOWER OF MUD. „

country has a tale or hiftory to relate, and the details by my
friend Cernazai, a good mineralogift of Udina, of a flimy rain
which actually fell there in the evening of the 6th of this
month, the wind having blown with violence from the eaft
for feveral days. The furface of the land which has been en-
tirely watered with this jflrange rain, appears to be from ten
to twelve leagues in diameter from the fea-fhore to the foot of
the Alps of Carnia. Here, my dear friend are the means of
eftabli Qiing a brick furnace in the higher regions of the at-
mofphere, by thofe who are already convinced that materials
are fufpended there, fufceptible of a fufion fimilar to that of
the interior of a volcano. I know not if the partifans of that
opinion which brings down the lavas from the moon, will be
able to derive any fupport from the mud which has jufl coated
the fields of Friuli ; but for my own part, I was at firft of
opinion, that the wind having been charged, in Sicily or near
Naples, with volcanic duft thrown up by a whirlwind, had
depoflted it at the foot of the mountains of Carnia, which
had obftru&ed the further progrefs of the clouds. But having
iince examined a fpecimen of the fediment in queftion, fent
to me by my friend at Udina, and which I forward to you
with this letter *, by a very powerful magnifier, I am con-
vinced that there is not the leail refemblance between this
argillaceous earth and the detritus thrown by volcanoes into the
upper regions of the atmofphere. It appears to me much
more probable that a hurricane, or perhaps a water-fpout had
pumped up the flimy water left by the large rivers wiien they
overfl w our richeft plains, and raifed it into thefc regions in
which the wind had acted upon it. It is in confequence of
fuch very, natural and common events, that worms, tadpoles,
and fmall fifties are frequently feen to fall from on high, with-
out any one dreaming of their proceeding from an aerial race
or from another globe.

You, my dear and learned friend, may make what ufe you
think proper of this limple unlkilful explanation.

* This earth is light, of the colour of brick«duft, and feems to,
be argillaceous. Note of J, C, Delametherie.

Lelter

METHOD OF EXTINGUIS HrNG FIRE, 103

VII.

Letter fromM. Van Marum toM. Berthollet. Containing
an Account of fame Experiments, fieiving the Method of exiin-
guijking violent Fires with very f mall Quantities of Water, by
Means of Portable Pumps,
SIR,

HEN I had the pleafure to fee you, during my flay in Hiftory of an
Paris, in September laft, you informed me that my experi- exttaeuifhing
ments, made on a large fcale fome years ago, to fhew the prac- fire,
ticability of extinguishing very violent fires with an inconfi-
derable quantity of water, were entirely unknown in France.
You at the fame time requefted me to fend you an account of
the experiments to be read at the national inftitute, and in-
ferted in the Annates de Chemie, My compliance with your
requeft has been prevented till now by the want of time. The
circiimflances which gave rife to the experiments were the fol-
lowing :

Nine years ago, Van Aken, a Swede, publifhed at Stock- Anti -incendiary
holm, Copenhagen, and Berlin, that he could very quickly ex- ^*ter oi Van
tinguifh large artificial fires with an inconliderable quantity of
a liquid which he called anti-incendiary, the competition of
which he had for fome time kept fecret. Having obferved in
the journals, that M. Van Aken had repeated his experiments
with much fuccefs in Berlin, before fome members of the aca-
demy of fciences, I wrote to the celebrated M. Klaproth, re-
queuing, if he knew the compofition of the anti-incendiary
liquid, he would communicate it to me ; intending to (hew, at
this place, the merit of the invention, by an experiment on a
large fcale. With this intention, as foon as I had received
M. Klaproth's communication, I caufed Van Aken's liquid to
be prepared under my immediate infpedtion. The compofi- its compofition,
tion was a folution of 40lb. of fulphate of iron, and 30lb. of ful-
phate of alumine, mixed with 20lb. of the red oxide of iron,
and 200lb. of clay. I then commenced a feries of compara-
tive experiments, by forming two combuftible mafles, alike in
all circumftances ; fetting them on fire, and extinguifliing one
of them with the liquid of Van Aken, and the other with com-
mon water, I was much furprifed to find, in feveral trials, that,

by

104- METHOD OF EXTINGUISHING FIRE.

On trial itprov. by ufing the two liquids in the fame manner, the fire was al-

ed lcfs effectual . ,. .„ . . , , , ,. ,, ,

than common -v extinguitned more quickly by the common water than by

water. the anti-incendiary liquor; but I obferved, at the fame time,

that a very inconfiderable quantity of water, if judicioufly di-
rected, would extinguifli a very violent fire. The refult of my
Experiment to firft experiments in this refpeei, led me to make others on a
^^^^ larger fcale, and which I mall defcribe alone: I took two
water is needful cafks, which had been full of pitch, and of which the infide
inextinguiming was yet we]j covered with that inflammable fubftance ; the
heads of thefe were then taken out, and in order to aftift the
operation of combuftion, I gave them a conical fhape, placing
the larger aperture of 20 inches diameter uppermoft, the other
of 16 inches diameter below, mounted on a three-legged
ftand, a few inches from the ground, fo that the fire might be
kept as brifk as polfible by the free current of air paffing
through the calk. I covered the infide of each calk with a
frefn coat of pitch, and having placed (havings of wood in each
cafli, I lighted them one after the other. I began to extin-
guish this fire when it was at its height. For this purpofe I
made ufe of an iron ladle capable of holding two ounces of
water, and provided with a very long handle, being kept at
thediftance of four or five feet from the apparatus by the vioT
lence of the fire. I carefully poured the water from this ladle
in very fniall ftreams over the infide of the calk, placing the
ladle on the edge of the calk, and moving it gradually along
the edge as the flames ceafed. In this way the firft ladle full
of water extinguifhed nearly one half of the fire, and what re-
mained was effectually put out by a fecond ladle full, ufed in
the fame manner. The linking fuccefs of this experiment,
induced me to repeat it in the prefence of many perfons, and
with care and attention in the application and management of
the water, I have more than once fucceeded in extinguifliing an
highly ignited calk with a fingle ladlefull of two ounces of
water,
•theory. The It will appear furprifing at firft that fo violent a fire could
fteam keeps off be extinguifhed with fo fmall a quantity of water ; the reafon
will, however, be eajily underftood when we reflect that, ac-
cording to well-known facls and principles, the flame of a
burning body will ceafe whenever its contact with the atmof-
pheric air is prevented: now, when a fmall quantity of water
is thrown upon an highly-ignited body, part of that. water is

inftantly

METHOD OF EXTINGUISHING FIRE. J05

inilantly reduced to fleam, which, riling from the furface of
the burning body, prevents the contact of the atmofpheric air,
and by that means puts out the flame, which cannot appear
again while the production of the fleam is continued.

According to thefe experiments, it appears that the art of Inftru&lons
extinguishing a violent fire with a fmall quantity of water, con- f™™^ °Je^
lifts in this : that the water be thrown on that part of the fire
which is the moft violent ; fo that the quantity of fleam pro-
duced, which fupprefles the flame, may be the greatefl poflible :
that water be continued to be thrown on the neigbouring in-
flamed parts, as foon as the fire has ceafed in that on which the
operation was began, and that all the burning parts be vifited
in this way as quickly as poflible. By thus following the flames
regularly with flreams of water, they may be every where fup-
prefled before the part on which the operation was began, fhall
have entirely loft by evaporation the water with which it was
moiftened : this is often neceflary to prevent the parts from
breaking out afrefh ; for, on the principle above-mentioned, a
burning body, of which the flames are fupprefled, cannot
be again in flames until the water thrown on it be totally eva- v
porated.

Being convinced by thefe experiments, that a fmall quan- Experiment on a
tity of water is fufficient to extinguifh ordinary fires, efpecially larScr fcal««
in an early flage. I have endeavoured to produce the fame
conviction among my fellow-citizens, by repeating the expe-
riments I have defcribed, and have advifed them to provide
themfelves with fmall portable pumps for their ufe in cafe of
neceffity. Many immediately followed my advice, and their
good effecl being proved, the number has gradually increafed in
feveral towns in Holland, efpecially after an experiment which
I made in this place in May, 1797, to fhew, on a larger fcale,
the advantages to be derived from a well-regulated direction
of flreams of water, in the extinguifliing even the mofl violent
fires, and with very fmall quantities of water, where portable
pumps are ufed.

The following is the experiment :

I prepared a (hell of dry wood, forming a room of 24 feet A wooden edi-
long, 23 feet wide, and fourteen feet high, having two doors fic<! fet.on **f
on one fide, and two windows on the other ; this box, provided ed.
with the wood- work of a roof, was uncovered above, and its par-
tition raifed fix inches from the ground ; fo that, having a cur-
rent

1CXS

Repetition;

Experiment at

Gotha.

METHOD OP EXTINGUISHING FIRE.

I

rent of air from the bottom upwards, the combuflion might be
rendered as brifk as poflible when the building fhould be fet on
rlre. The infide of the partitions were ftrongly pitched, and
were befide covered with twitted ftraw, which was alfo
pitched. To the inner part of this ftraw covering, I fattened
wood (havings, and befides this a coarfe cotton cloth, foaked
in oil of turpentine, in order that the whole infide of the build-
ing might be quickly on fire. Very foon after lighting it, the
flames being rendered more britk by the wind, were every
where fo violent, that it was confidered by my affiftants as im-
poffibletoextinguifh them: I fucceeded, however, after the
method above directed, in little more than four minutes, and
with five buckets of water, a part of which was walled by the
negligence of my affiftants, as was proved by the following
experiment :

Having invited only a few perfons to witnefs this, my firft
experiment, on the 8 th May, I repaired my apparatus, and
repeated it on the 1 1th, before a great number of fpe&ators :
the flames were no lefs violent than in the preceding experi-
ment. I now undertook to direct the jets of water in perfon,
and fucceeded in extinguifhing the fire in three minutes, and
employed only three buckets of water, each containing about
eighteen pints.

Being at Gotha in July 1801, the duke and duchefs of Gotha
prefled me much for a repetition of my experiment at their own
expence, the details of which they had feen in the German
journals ; in order to make the matter more fully underftood
in that part of Germany, where, as in every other place, fires
often make the moft dreadful ravages, in confequence of the ig-
norance of the method of properly ufing the fmall quantity of
water which they may have at hand. The obliging manner in
which their highneffes made their requeft, and my own wifh to
render it more generally ufeful, induced me to repeat it. The
celebrated aftronomer, Von Zach, affifted me in this experi-
ment, and had the goodnefs to infert an account of it in a
German periodical paper, intitled Reichs Anrieger, 6th Auguft,
1798, No. 119.

M. Lalandearrivingat Gotha on the 30th July, four days after
this experiment, was well acquainted with its refults, and, as
he has iince told me, fpoke of it at the National Inftitute, foon
after his return to Paris j but informed me, at the fame time,

9 that

METHOD OF EXTINGUISHING FIRE. ]07

that the truth of his account was doubted. In order to clear
away all doubt on that head, I fubjoin the following liberal
tranflation of the verbal procefs of the experiment which Von
Zach had drawn up, and inferted in the above-mentioned pe-
riodical paper :

Do&or Van Marum * being at Gotha, in the courfe of a lite- Verbal procefs of
rary journey, which he was making in Germany in 1798, the methodof ex-
(Juke of Gotha, well known as an amateur of the phyfical and tinguiihmg fire,
mathematical fciences, fignified his defire to fee, on a large
fcale, that experiment of extinguishing fires, the effect of
which M. Van Marum had (hewn him, in extinguishing a
pitched calk, fet on fire, with a fmall ladle of water. He
caufed a building to be constructed under M. Van Marum's di-
rection, in the duchefs's garden, of equal dimenfions in all re-
fpects with that ufed for the fame experiment at Harlaem,
which was of 24- feet long, 20 feet wide, and 14 feet high. It
had two doors on the north-eaft fide, and two window-like
openings on the north-weft fide ; the top was left entirely open
to give the flames a free vent ; the infide of this receptacle
was plaflered with pitch, and afterwards covered with ftraw
matts, on which melted pitch had been poured. To the bot-
tom of thefe matts, cotton wicks, foaked in fpirits of turpen-
tine, were fufpended, that fo the building might be every
where on fire at the fame time. In this ftate the fire, excited by
the wind, was foon fo violent, that the flames, with thick
clouds of fmoke, were carried feveral feet above the opening
of the roof, and fo fiercely, that the fpectators afiembled about
the building quickly drew back ; many were of opinion that
it would not be poffible to extinguifli it, but that the building
muft be reduced to afhes. When the ftraw mats were entirely
confumed, the interior wood work of the building was foon on
fire in every part. The raoft unfavourable circumftances at-
tended this experiment ; for the wind drove the flames directly
through the two doors on the north-eaft fide, by which it had
been intended to introduce the ftreams of water to extinguifli
them : but notwithstanding this, M. Van Marum placed a
fmall portable pump (or engine) before the door in that part of
the north-eaft fide of the building neareft to the fouth»eaft-fide ;

* The remainder of this memoir being the words of the report,
it has not been marked as a quotation, ---N,

without

108 METHOD OF EXTINGUISHING FIRE.

Verbal procefs of without regarding the apprehenfions of his affiftants, he fet It
the method of *n ac^on> and placing himfelf before this door, as near as the
extinguishing intenfe heat of the fire would admit, he directed the flreams of
rc* water firft towards the fouth-eaft fide, and as near the door as

was poffible, and continued until the flames were extinguished
on the fide, and fprinkled with water in the fame direction ;
after which the water was directed along the fouth-eaft fide,
and afterwards the north-eaft, fo that in a few minutes the
flames were got under, and the burning partitions were extin-
guifiied. After this the pump was placed before one of the
openings in the north^weft fide. He alfo very foon extinguifiied
the fouth-eaft fide ; and laftly, coming to the centre of the build-
ing, where the fire appeared here and there in the chinks of the
boards and the holes left by the nails, breaking out at intervals
in fmall flaflies, he entirely extinguiflied them, and thus per-
fectly fubdued this violent fire. It was eftimated by feveral
of the fpeclators, that the fire was extinguifiied at moft in
three minutes from the commencement of the action of the
pumps to the time when the wood juft remained burning, and
broke out afrefh in fome places ; thefe renewals were however
fo inconfiderable, that the burning parts were quenched by
means of fome wet rags fattened to a fiick. Before fetting
the pump to work, itsrefervoir was filled with four buckets of
water ; but in carrying it to the firft window of the building,
and from thence to the middle of it, near a bucket full was
fpilt ; fo that it may be pofitively affirmed, that this violent fire
was extinguifiied with three buckets of water, excluding that
which was afterwards ufed to quench thefe parts of the build-
ing which remained red. It was eafily obferved, when the
fire was out, that not only the ftraw matts were burned, but
the entire wood work of the building had been on fire, info-
much that the fmalleft part of wood could not be found in the
infide of the building which had not been more or lefs fe-
verely burnt. The north-eaft fide in particular, againft which
the wind drove the flames with the moft violence, was entirely
charred.

The experiment made at Gotha differed materially from
that at Harlaem, as the flames and thick fmoke, which came
out at the doors on the latter experiment, rendered accefs to
the building with the pump very difficult ; fo that it was only
by means of perfuafion, and the courageous example which

M.Vaa

METHOD OF EXTINGUISHING FIRE. \Qg

"M. Van Marum himfelf fet in leading his affiftanis and dire6L Verbal procefsof
ing the operations of the pump, that he could prevail on them J^^od of °
to face the danger, which they confidered as very dreadful. extinguilhing

Therefult of the foregoing fafts is, that in applying the fire*
method of extinguifliing fire, the circumftances to be ob-
ferved are thefe, that, to extinguifh the moft violent fire, it is
only neceflary to wet the furface of the burning matter in the
part in which the flames are feen, and that for this purpofe
only a fmall quantity of water is needful, if the parts be wetted
in the proper manner. In operations of this kind, therefore,
particular attention mud be paid to throwing the water in fuch
a way, that the entire furface of the burning part fhall be
wetted and extinguifhed, and that in fuch a way that an extin-
guiflied part fhall never be left between two others which are
in flames ; for if attention be not paid to this, the heat of the
flames burning here and there will quickly change the water
with which the part has been wetted into fleam, and the whole
will again take fire. In order, then, to extinguifh a fire in all
cafes, no more water mull be thrown on the burning part than
is needful to wet its furface ; and this I conceive to be all that
is requifite to extinguifh a fire whatever may be the circum-
ilancesof its origin.

VIII.

Report, prefented to the Clafs of Accurate Knowledge of the Aca-
demy of Turin, in the fitting of the 2d Nivofe, (Dec, 23, 1802,)
in the Year 1 1 , on the Action of Galvanijm, and on the Appli-
cation of this Fluid, and that of Electricity, in the Healing
Art, by Antoine-Marie Vassali Eandi. *

JL HE galvanic experiments, made the 22d and 26th of laft Hiftorical intr*.
Thermidor, before a confiderable number of fpe&ators, by duftion'
your alTociates Giulio, Rofli, and myfelf, On the heads and
trunks of three perfons who had been decapitated, the report
of which you have caufed to be printed, excited many ques-
tions refpe&ing this agent, and, by analogy, on electricity.
Thefe two fluids, and their ufes, have furnifhed the fubjecl of

* From the Journal de Phyfique, Germinal, An. XL

the

110 ON THE ACTION OF GALVANISM*

the ordinary converfations of well-informed people ; and, a3
always happens, when a difcovery is the topic, fome have ex-
aggerated its advantages, and others have defpi fed it. This
diverfity of opinion led our aflbciate, citizen Charles Boffi,
(qu. Rofli) to propofe two judicious queftions to me, which I
have endeavoured to refolve in the following letter, written to
him in the beginning of Vendemiaire. I could eafilyhave fwelled
it to greater extent by additional reafons and numerous inftances
of cures obtained by means of galvanifm and electricity, as
well as with others of misfortunes, occafioned by thefe fluids,
and with the conftant correfpondence which I have obferved
between the moral powers, that is to fay, the ftrength of mind
and courage of the viclims of juftice, and the effects of the
galvanic fluid upon their bodies ; but thefe obfervations belong
to the general report of the experiments we have made fince
, the 26th Thermidor ; I (hall, therefore, confine my felf to pre-
fenting you the letter which I wrote at the above-mentioned
time.
Queftions for " You afked me, in one of our late academic fittings,

difcuflion. whence it arofe that, after the number of experiments made

by the raoft able philofophers of the pad: age, on the electric
fluid, the difcovery of which is one of its moft brilliant con-
quers, fo little is determined relative to the medical action of
this fluid on (he human body ; and whether galvanifm appears
really already to promife refujts of more utility in the art of
healing ? I fhail inform you what my opinion is, or rather, I
fliall fubmit to you the inferences, which the different experi-
ments made by me alone, or in which I have affifted and wit-
neffed, have enabled me to draw with more certainty than I
ever dared to hope when I began ferioufly to engage in this
purfuit.
Galvanifm con- I confider galvanifm as a modification of electricity, which
fidered as a mo- renders that fluid more active; as the fmall flame, ieparated
tricity. " ty lne blow-pipe, is infinitely more powerful than the large

flame from which it proceeds. I have read feveral experi-
ments to the clafs, which fupport this parallel between electric
Proofs of its ef- city and galvanifm. Animals which had been only ftunned
fefts on animals, by tjie moft powerful explofions of the magic table, were
killed in lefs than three minutes by galvanifm, which was far
from being flrong.

The

ON T«£ ACTION OF GALVANISM. HI

The fluid of a pile of 25 pair of plates of filsrer and zinc, on metals and
of the fize of a crown piece, feparated by difcs of pafteboard water»
moiftened in* water, faturated with muriate of ammonia, oxi-
dates the metals by decompofing the water, while it is fcarcely-
perceptible to the fingers, and (hews but very fmall fparks.
Brilliant electric fparks, which are fharply felt by our bodies,
do not oxidate the metals, or decompofe the water, if they are
not fo ftrong as to explode. On pafling the galvanic ftream
through the body of a frog, it has happened that his humours onYrogs.
have been decompofed, and I have feen him fwell fo prodigioufly,
that he was unable to fink himfelf below the water, though
perfectly lively ; this I have never obferved in frogs tormented
by exploding fparks. All thefe facts, to which I could add many
others, prove the fuperior activity of galvanifm, when com-
pared with electricity. Hence it refults, that the fluid from utility of Volta'j
the electro-motor of Volta maybe highly ufeful in cafes where ele&ro-motor.
the ordinary electricity is not fufficiently active. You are ac-
quainted with fome of the experiments which I have made
with my colleagues, Julio and Roffi ; we have others ftill more
interefting, which have determined phyfiological facts that
have always been doubtful from a want of the means of veri-
fying them. Laftly, we have tried the application of it in fe-
veral diforders with the greateft fuccefs. Here are three in-
ftances :

A lady, about 30 years of age, after a continuation of vio- Cure of agutta
lent pain in the head, loft the fight of the right eye. Citizen ^fm^y gaI~
Roffi was confulted on the complaint, and after a careful exa-
mination of this eye, which to appearance was as healthy and
clear as the left, he concluded that it could be only a paralytic
of the optic nerve, or what is called a guttafercna, which, al-
lowing the patient to fee only a thick mill, increafed her mif-
fortune, while it alfo contributed to derange the fight of the
other eye, fo that the was in continual fear of falling, and was
not even able to difcern with the right eye thofe objects which
were within her reach. Roffi, being indifpofed, fent to me to
apply galvanifm. I formed a pile of thirty pair of fuch plates
as are mentioned above, and making ufe of gold cords for con-
ductors, I cauled the galvanic ftream to enter clofe to the ex-
ternal angle of the eye, and to pafs out fometimes through the
eye-brow ; fometimes exactly at the opthalmic vein, which
goes through the hole of the orbit ; and fometimes clofe to the

internal

vanifm.

U2 ON THE ACTION OF G AL V ANlsflf .

internal angle of the fame eye. The operation was attended
with fome pain ; it caufed tears to flow abundantly ; but after
having received fucceflive galvanic (hocks for half an hour, the
fight of the eye began to be reftored. Being unwilling to fa-
tigue the lady, and to allow time for nature to act, the opera-
tion was fufpended until the evening, when it was repeated for
thirty minutes alfo. The following day the eye began to per-
ceive the outlines of bodies. Having repeated the operation
for three fucceffivedays, (lie not only was capable of feeing ob-
jects and the phyfiognomy of perfons, but even the balls of their
eyes. Before this operation, in confequence of a confultation with
doctor John Baptifte Anforni, firft phyfician to the Hofpital de
la Charitd, I had galvanifed a girl of 27 years of age, of a
Cure of a para- melancholy habit, who, after fome flight attacks, had a hemi-
^feyae^eya^jn_of paralyfis of the right tide, which particularly affected the arm,
the cheek, and the eye. The other fymptoms had yielded to
bleeding, and the ufe of fuch other remedies as had been indi-
cated, but the eye remained eonftantly fixed, with pains in its
mufcles. Ten minutes of galvanifation were fufficient to ex-
cite an abundant flood of tears, and a difcharge of water
through the noftril on that fide which had been always clofed
after the above attack ; the pains in the mufcles were alfo
much alleviated ; (lie could even turn the eye to either fide,
but had great difficulty to raife or deprefs it, accompanied with
a fenfation of weight round the eye. The operation was re-
peated after a day's repofe, which reftored the complete free-
dom of motion to the eye, and freed it from every unpleafanfc
fenfation.

Thefe two operations were performed in the prefence of fe-
veral perfons, and executed almoft wholly by citizen Hea-
cinthe Carena, teacher of phytic in the national college of
Turin.

The advantages of galvanifm will appear flill more deci-
fively to you by the cure of the hydrophobia, lately accom-
plifhed by citizen Roffi, who will give a detailed and exact ac*
count of it in an interefting memoir, on which he is employed.

A man whohad been bitten on the middle finger by a mad dog
came to confult him for the pains he felt in his arm and back,
and particularly in the finger, which had been bitten a month
before. The actual cautery, applied to the finger, removed
the pains, but in a few days they returned, accompanied by
4 fymptoms

Cure of the hy
drophobia by |
'galvanifm.

ON THE ACTION OF GALVANISM. 113

fymptoms of hydrophobia. He could no longer bear the fight
of water without flmddering ; an inflammation of the throat
obftructed his fwallowing even chewed bread, and a violent
defire to bite appeared every inftant.

In this ftate he was brought to citizen Rofli, who perceiving
that he could not endure the fight of water, or even of any
mining body, prepared, in another room, a pile of 50 pairs of
zinc and lilver plates, feparated by 50 difcs of pafteboard,
moiftened in a folution of muriate of ammonia ; he then made
ufe of fmall ftrips of moiftened white brown paper for a con-
ductor, on which he caufed the naked feet of the patient to be
placed, and at the moment he opened his mouth to bite, he
thruft in the end of the conducting-rod, which communicated
with the other extremity of the pile. The patient fuffered
much during this operation, which, after feveral (hocks, ren-
dered him fo weak, that he was unable to ftand : being then
extended on the floor, he was galvanifed with facility. The
operation produced a copious perfpiration. After fome time,
Rofli caufed the man to be carried home, with directions that
he fhould be brought again the following day, that the opera-
tion might be repeated. It was at two o'clock in the afternoon
that the patient was galvanifed, at fix o'clock on the following
morning he came alone to citizen Rofli, to tell him he was
perfectly cured, for he felt no pain, nor difficulty in fwallow*
ing, and had entirely loft all averfion to water and other li-
quids : but no arguments could induce him to fubmit to ano-
ther operation.

In a few days after, fome flight pains having caufed him to
dread a new attack of the hydrophobia, he returned to Rofli,
who, by galvanifm, again removed all the fymptoms. This
cure was likewife performed in prefence of feveral people.
The patient is poflefled of fuch fenfibility, that more than a
month afterwards he felt the fenfation of galvanic fliocks as
far as his fhoulders, which I could fcarcely perceive beyond
the third joint of the finger, and I am not among the leaft fuf-
ceptible. From thefe eflays you will perceive what benefits
may be hoped from galvanifm. I do not doubt that an agent Benefits to te
of fuch activity may be the means of preferving many indivi- expe&ed from
duals from the grave, by applying it at the moment when an
accidental caufe has fufpended the functions of the vital organs.

Vol. V.— June. I This

1 14* ON THE ACTION OF GALVAtflSMi

This will become more obvious from the explanation of the
medical action of electricity on the human body.
Difference of Several celebrated writers have placed electricity among

mjTeTearicity " ^e mo^ certain ana* active remedies ; others have demonftrat-
arifing from its ed the inutility and even danger of this fluid as a remedy ;
implication. each of them haye fupported their opinion by well-afcertained

facts.

Nothing is more eafy to be accounted for when we reflect
on the very great number of thofe, who, in the application
of electricity as a medicine, have only acted empirically with-
out having confulted the nature of the diforder, or of the agent
by which they intended to cure it. It is for this reafon that, in
the memoir which will appear in the volume of the academy,
I have recommended the greateft caution in the ufe of galvan-
Electricitymay ifm, which, like electricity, may do a great deal of harm ;
do harm when an(j tnat j nave aflerted that this remedy, though very excel-
pliedt lent in itfelf, has done more harm than good in confequence of

improper application. I (hall not fpeak of the chimerical pro-
perties which, iii the enthufiafm of novelty, have been attri-
buted to electricity, fuch as that of conveying to the human
body, by friction with them, the action of remedies fealed up
in glafs tubes.
New remedies ^ 's notorious that it is the fate of every new difcovery to be
injudicioufly fQ over-rated, that its opponents are at no lofs for reafons to
9 ' object to it, but after fome time things are brought to the pro-
per level, eftabliflied by the more intimate knowledge of the
agent. Thus thofe who are fufficiently acquainted with the
properties of electricity, know how to diftinguifli the cafes in
which it can be employed to advantage from thofe in which
it would be injurious. Of ten patients affected with the
fame complaint, who undergo a fimilar courfe of electricity,
five may be entirely cured, and the other five fhall be very
ill.

Thofe who are cured extol electricity as the belt of reme-
dies ; thofe who fufFer fay that it only increafed their com-
plaint ; both fpeak from accurate experiments ; both are right
and wrong at the fame time from making the application too
general, that is to fay, becaufe they do not difiinguifh the
caufe of the diforder which requires to be oppofed by the ufe
of electricity. I will explain myfelf: The fame complaint,
4 for

ON THE ACTION OF GALVANISM. \ Jg

for inftancejbiatica *, may be occafioned either by obftructed
humours, by their too great quantity, or by a defect in the re-
action of the folids; it may alfo arife from organic defects,
from a change in the humours, from a venomous, or as it is
called an acrid principle, or from a peculiar virus which is
found in the humours.

Thofe five who are affected from an obftruction in the hu-
mours receive the greateft benefit from electricity, which fets
them in motion ; the other five, who are tormented by a fcia-
tica proceeding from vitiated humours will grow worfe under
the electric treatment, which increafes the acridity of the hu-
mours, carrying off part of the water which kept the poifon
diluted. This theory of the effects of electricity on the human
body is founded on the nature of this fluid, and on the proper-
ties it manifefts in numerous experiments.

The electric fluid tends conftantly to an equilibrium, and Conftant ten-

this tendency is fo ftrong, that it is feen to penetrate through eSic flu^d to

the air to a certain diftance, and to fpread itfelf on idio-elec- an equilibrium,

trie bodies. It is this tendency which caufes electrifed water urged a/f.tne

• in ii .„ » . , mode of its ac-

to run in a continued uream through capillary iyphons, whence tion.

it pafles flowly in drops, if the electrization is flopped. It is
by the fame tendency that electricity accelerates the circulation
of the blood in animals f, and of the humours in vegetables.
It is, Iaftly, by the fame tendency that when the electric fpark
pafles from one conductor into another by connecting wires, if
the cohefion of the body be not fufliciently great to prevent it
Jt takes with it, in its paflage, fome of the conducting particles,
which ferve it as a vehicle. This property, which is mani-
fefted by the ordinary effects of thunder, and of feveral expe-
riments, (hews the caufe of the increafed evaporation of elec-
trifed liquids, and the greater tranfpiration of animals and ve-
getables under fimilar circumftances. It is clear, therefore,
that in every cafe of obftructed humours, if other fymptoms do
not forbid, electricity will be a very good remedy ; on the

* Doctor Balbis obferved to me, that all the fpecies of fciatica
could be very well accounted for without having recourfe to the
hypothec's of corrupted humours j I replied to my learned brother,
that it was mydefire to compare my theory with the chief theories
of fciatic affections without attending to their probability.

f Van Marum feems to have afcertained that it does not produce
this effect. See his account of the Haarlem machine. — N.

I 2 contrary,

116 ON THE ACTION OP GALVANISM.

contrary, if the complaint proceeds from vitiated humours, or
from a diluted virus being contained in them, then electricity,
either by evaporating the diluting humour, or by caufing a
greater change, will be hurtful. Hence it is evident, that
electricity and galvanifm ought to be ufed with the greateft
circumfpeclion, and that the nature of the diforder, as well as
of thefe fluids, mult be confidered, before it can be decided,
whether the application is proper or not. It muft alfo be ob-
ferved that this remedy, on account of its activity, like all
other remedies, however good they may be, becomes dan-
gerous when abufed.
Anlnftanceof I might bring many inflances of injury occafioned by the
ImprLenTap^ mifapplication of electricity, even in cafes where a lhort time
plication of gal- before it had been indicated. But I (hall only produce one
vanifin. cafe reiatjve i0 galvanifm. A young female had been cured

of pains in the mufcles of her face by galvanifm ; but after the
cure, in confequence of continuing the application (he did
herfelf harm, which increafed by the galvanifation, and did
not ceafe until fhe left herfelf intirely to the powers of nature,
affifted by nourifhing food. The patient, who is not capable
of forming an opinion on the ftate of his health, muft therefore
confult an able phyfician, one who does not defpife nature and
new discoveries. By this caution he will never be hurt by the
application of ele&ricity or galvanifm, which as Boerhaave
fays (Elem. Chemicc, pars. 3. procerus 198.) of another very
active remedy: mire praftat in multis incurabilibus : at prude ti-
ter dprudenti medico, abjiine fi metfwdum nefcis.

IX.

Account of two Mufquets of peculiar Confiruclion for the Purpofe
of quick firing. — W. N.

Two mufquets JL HE two pieces are the property of the Rt. Hon. the Earl

belonging to the f Warwick , who has permitted me to examine and defcribe

ear. of War- r

wick. them : both have the name Wm. Martindale, Londini, in gold

upon the barrel, and the falhion of mounting them is little dif-
ferent from that at prefent ufed. This name might perhaps
fix the time of their fabrication near ;y, if the regifters of the
Armourer's Company, or other fimilar books were to be con-
futed.

ACCOUNT OP TWO MUSQUET8. J 27

fulted. I fhould fuppofe them to have been made about a
century ago. Neither of them is in good condition.

One of thefe pieces is conftru&ed precifely on the principle, One refembles
and with the fame parts, as the piftol belonging to Lord Ca-^sC^oe|'
melford, which was defcribed in our laft Volume, page 250,
but the workmanfhip is not fo good. The chamber piece is of
brafs, and the barrel is 30| inches long. I think the maga-
zine would hold nine or ten balls.

The fecond piece is on a different conftruclion. It feems Defcrlption of
to have been invented before the other, probably by the fame Mother. jt
perfon. The barrel, which is 39 inches long, has no breech primes at once*
pin, but is perforated clearly through. The ufual charge of
powder and ball is lodged in a feparate iron cylinder, (Fig. 3,
Plate VIII.) two inches and three quarters long, and of the
fame bore as that of the piece itfelf, namely a little more than
half an inch, or 0.54 inch. The metal of this cylinder is about Defcrlption of a
one twelfth of an inch thick, and it is lodged for actual fervice ?uic1c firing*
in the pofterior part of the bore of the gun, which is enlarged
for the purpofe of receiving it (fee Fig. 2, letter G.) The
gun is provided with five of thefe cylinders, four of which are
lodged in cells in the flock ready for ufe, while the fifth is
fuppofed to be placed in the gun itfelf. There is a touch hole
in the cylinder which anfwers to another in the barrel that
opens into the pan ; and this laft is a cylinder fixed to the bar-
rel itfelf, having an excavation on its upper furface for lodg-
ing the priming (B, Fig. 1 and 2.) Immediately behind the
breech end of the barrel there is a receptacle in the ftock, or
rather in the barrel itfelf (E), for lodging the charged cylinder
previous to Aiding it into the chamber of the barrel. It is to
be obferved, that the metal of the barrel is continued back
four inches farther than the termination of the bore, and that
it is in this ftrong metallic part that the receptacle E is made.
The lock itfelf is attached to the piece by having the part im-
mediately beneath the (hutting face of the hammer, fitted upon
the fixed cylindrical pan B, and fecured by an end fcrew fo as
to move round upon that cylinder. So that it is to be under-
stood, that the lock plate can either remain in the ufual por-
tion, or may be brought up to a polition in which its length
fhall be rather more than at right angles with the length of the
barrel, as in the line H. In this laft pofition the priming is
given, and the piece cocked exactly by the fame means as in

kord

U3 ACCOUNT OF TWO MUSO.UETS.

Dsfcription of a Lord Camelford's piftol, excepting that here the lock itfelf
quickUfiring. performs the motion, inftead of the cylinder that carries the
pan, which continues unmoved. In Fig. 1 . the flud D pro-
ceeding from the barrel reacts upon the hammer, and (huts it
at the fame time that the flat bar proceeding from the cock
comes to reft on a notch in the barrel, and caufes it to acquire
the pofition of full-cock. Fig. 2. is a fection of the' barrel feen
endwife, and of the lock railed up. When the lock, and the
piece to which it is fixed are returned to the ufual fituation,
the receptacle E is filled by a folid piece of iron, which forms
a portion of AC, and effectually refifts the recoil which the
piece C would otherwife undergo. At A is a catch that ferves
to fecure the lock and apparatus in the laft-mentioned pofition ;
but when the gun has been difcharged, and the fubfequent
operations are to be relumed, that catch is drawn back, and
the fpring C throws the appparatus of the lock a little way up,
in order that it may be then raifed, and the empty charge-
piece taken out and another put in, &c.

It may perhaps be confidered as loofe conjecture to fuppofe
thefe guns were originally invented by the Marquis of Wor-
cefter, whofe " Century of Inventions" was publifhed about
1655, and hath fince been reprinted by various publifhers,
and in periodical works. Out of this work I copy the follow-
ing, which will at leaf! amufe the reader.
Accounts of in- « 58. How to make a piftol difcharge a dozen times with
quick firing by °nce loading, and without fo much as once new priming requi-
thc Marquis of fite, or to change it out of one hand into the other, and flop
Worcelter- one's horfe."

This feems to have been the piftol of Lord Camelford be-
fore defcribed in our Journal, and the firft of the guns here
mentioned.

'*. 69. Another way as faft and effectual, but more proper
for carabines.

" 70. A way with a flafk appropriated unto it, which will
furnifh either piftol or carabine with a dozen charges in three
minutes time, to do the execution of a dozen fhots as foon as
one pleafeth proportionably.

"71. A third way, and particular for mufquets, without
taking them from their refts to charge or prime, to a like exe-
cution, and as faft as the flafk, the mufquet containing but
one charge at a time."

I fup-

ACCOUNT OP TWO MUSQUETS. \ \\)

I fuppofe this laft to have been the contrivance, of which the Accounts of in-
(ketch is given in Plate 8. ventions of

'* 72. A way for a harquebufs, a crock, or fhip mufquet, Jh^Marqufs of
fix upon a carriage, {hooting with fuch expedition, as without Worcefter.
danger one may charge level, and difcharge them fixty times
in a minute of an hour two or three together. •

" 73. A fixth way, moil excellent for fakers, differing from
the other, yet as fwift.

"74. A feventh way, tried and approved before the late
king (of ever blefled memory) and an hundred lords and com-
mons, in a cannon of eight inches half quarter, to (hoot bullets
of 64 pounds weight, and 24 pounds of powder twenty times
in fix minutes ; fo clear from danger, that after all were dis-
charged, a pound of butter did not melt being laid upon the
cannon-breech, nor the green oil difcoloured that was firft
anointed and ufed between the barrel thereof and the engine,
having never in it, nor within fix feet, but one charge at a
time."

The diameter of this piece is fully fufficient to carry an iron A Chlnefe can-
ball of 64lb. I fuppofe this contrivance to have been the non with a num-
fame as one which was ufed in China much later, viz. in the chambers,
year 1725, in the third * year of the emperor Yong-tcheng,
and made from a model prefented by the chief of one of the
provinces. Its bore was about one inch, and confequently it
threw a ball of lefs than four ounces of iron, or fix of lead. A,
receptacle was made in the hinder part of the barrel, fimilar
to the mufquet juft defcribed ; but infiead of the charge being
lodged in the kind of iron cartridge, Fig. 3, Plate VIII. there
was an a&ual breech piece for containing the charge, which
piece was lodged in the receptacle when in fervice, and could
be placed or replaced by an handle like that of any other vef-
fel. The gun was provided with four of them. If the Mar-
quis of Worcefter's great gun was of this defcription, the heat
would be chiefly produced in the fhifting piece, and confe-
quently the gun would, as he fays, continue cool. This fhift-
ing piece muft have been very weighty, even without its
charge, and little durable in its fitting.

'** 75. A way that one man in the cabin may govern the Inventions of
whole fide of fliip mufquets to the number, if need require, of Worcefter fo°r
2 or 3000 fhots. quick firing.

* Memoirs concernant les Chinois, vol. 7. Paris, 1782.

" 76.

\20 0P *AIN.

*' 76. A way that againft feveral advances to a fort or caf-
tle one man may charge fifty cannons, and flopping when he
pleafeth, though out of fight of the cannon.

" 77. A rare way likewife for mufquetoons, fattened to
the pummel of the faddle, fo that a common trooper cannot
mifs to charge them with twenty or thirty bullets at a time,
even in full career.

" When I firft gave my thoughts to make guns (hoot often,
I thought there had been but one only exquifite way invent-
able, yet by feveral trials and much charge I have perfectly
tried all thefe."

X.

Of Bain. By Richard Kirwan, LL.D. F.B.S. Prefi-
dcnt of the Royal lrijk Academy, fyc. *.

Rain is not AJlMINUTION of the temperature of air, replete with
frigemion*6" moifture, below the degree at which its faturation takes place,
whether this refrigeration were caufed by rarefaction, or by
the intermixture with colder air, has been generally fuppofed
the caufe of rain ; but this hypothefis in both its branches has
been fatisfactorily refuted : the firft by Sauflure f and the fe-
cond by De Lucj. And in fact refrigeration will indeed
feparate moifture from air cooled below the temperature ne-
for this produces ceflfary to hold it in folution. But this feparation will termi-
dew or clouds. nate? if gradual, in the production of dew, as already feen,
or, if fudden, in the production of a cloud, as in the experi-
ment of Tornea mentioned by Maupertuis, but cannot nor has
in any inftance produced rain.
Rain is caufed Rain is the immediate refult of the union of the particles

of eleclriclty0n wn'cn ^orm c^ou^s J ar>d tn»s union is the confequence of the
fubtraction of the electric atmofpheres which keep them at a
diftance from each other ; and this fubftracYton is itfelf the con-
fequence either of the fupcrior attraction of better conductors
or of the attraction or repulfion of other clouds through the
ctufes mentioned in the firft fection of this chapter. The

* Irifh Academy, 1802, p. 487.

f Hygrom. § 2z4.

% De Luc Idees de Meteorologie, p. 43, &c.

confequence

• P RAIN. 121

confequence of the attraction of clouds is their incorporation,
and the refult of their incorporation is the increafed volume of
their conftituent particles, an increafe proportioned to the at-
traction that produced it; the increafed volumes, thus pro-
duced, form thofe drops whofe collection we call rain. The
weight of thefe being fuperior to the refiftance of air, they
neceflarily defcend, and the caufe of their different fize is thus
clearly difcerned.

The repulfion of clouds fimilarly electrified, and not greatly Developemcnt of
differing in magnitude, terminates in a bare increafe of dif- ** effe"s*
tance ; but, if their magnitudes be much difproportioned, it
may terminate in attraction, or at leaft in forcing the confti-
tuent particles into clofer contact, and thus by increafing their
magnitude effect the fame refult.

When the attraction takes place between clouds differently
and highly electrified, and within what electricians call the
ftriking dijlance, the electric fluid is fet free, the coalefcence of
the nubiious particles is more rapid and complete, and hence
the large drops that follow flafhes of lightning, or even floods,
where the quantities both of vapour and electron are confider-
able, as between the tropics.

Upon thefe principles moft of the phenomena relative to rain
appear to me eafily explicable ; of thefe the moft remarkable
are :

1. That rains are more copious but lefs frequent in the Phenomonaof

fouthern parts of our hemifphere not much elevated over the rain#

fea, than in the more northern latitudes. They are more co- More copious but

pious when their productive caufes occui?, evidently becaufe lefs fre<juentin
, i, " - » - , . . , . , , low latitudes,

the quantity of lufpended vapour is much greater in the hotter

than in the colder regions ; but they are lefs frequent, becaufe
the variations of wind in different directions which introduce
and intermix clouds indifferently electrified are lefs frequent ;
this might be proved by inftancing the rainy feafons between
the tropics, were it not that this illuftration would extend this
paper to too great a length. Even in moderately elevated
iituations between the tropics, if infulated and of fmall extent
as the ifland of St. Helena, it feldom rains.

2. That, in the temperate latitudes, rains are alfo more Moft copious
copious, though commonly lefs frequent, in fummer than in thou8. *"ft f™*
winter, for the reafons already afjigned. Dry fummers are
then the confequence of uniform winds, from whatever quar-
ter

122 or RAfN.

ter they may blow, as wet fummers are of their variation, par-
ticularly if in oppofite directions, and if they reach heights
fufficient to intermix the clouds that fubfifted during the reign
of their antagonifts.
Southerly winds 3. Southerly winds are moft frequently accompanied with

'Euro ra'n 'n rain' m n10^ Parts °^ EuroPe at leaft> and probably in moft
parts of our hemifphere ; but northerly and eajlerh/, with clear,
dry, and ferene weather. Becaufe foutherly winds are not
only warmer, proceeding from warmer climates, butalfo more
highly electrified than the foil of the colder countries into
which they flow. Hence the copious vapours they contain are
quickly deprived of part of their electron, and thus converted
into clouds; but the fuperior ftrata of the atmofphere. under
which the fouthern air is introduced, not being fupported by air
as denfe as that which fubfifted under them before their intro-
duction, necetfarily defcend and mix with the inferior fouthern air ;
by this intermixture they are warmed, and deprive the clouds
already formed and in its vicinity of part of their electron, or
perhaps in conformity to the eleventh principle, they are them-
felves deprived of part of their electron by thofe clouds, and
the vapours they contain are thus converted into clouds ; in
either way clouds differently electrified mufr be formed. Hence
proceeds their gradual attraction to each other which termi-
nates in thofe gentle fhowers that ufually accompany this wind.
Northerly and eafterly winds on the contrary, proceeding from
colder countries are lefs highly electrified than the foil of the
countries they invade ; and hence from the oppofite reafons to
thofe juft mentioned they introduce ferene weather and a dik
pofition adverfe to nubification.

The reafons hitherto adduced to explain the different effects
of thefe different winds, evidently arofe from an ignorance of
the origin and progrefs of thefe winds. It was imagined that
foutherly winds, flowing into colder countries were fuddenly
cooled by an intermixture with the colder air of thofe coun-
tries, and that thus their vapours were condenfed into rain,
yet, even fo, this intermixture could only produce clouds and
not rain, but in fact this intermixture cannot take place, ex-
cept with the fuperior and unmoved ftrata of the atmofphere,
and thefe alone could not produce numerous clouds, much
lefs copious rains ; for the air of the countries into which thefe

foutherly

OF RAIN. 123

foutherly winds flow, mud itfelf have flown northwards, be-
fore the more fouthern air could enter upon them, as (hewn
p. J29.

Moreover, foutherly winds retain much warmth, and north-
erly winds are fo much colder in the countries into which they
are introduced, that their temperature cannot be fuppofed
fufrlciently altered to depofit much vapour in the one cafe, or
diflblve much of that already condenfed in the other ; on the *
contrary, the warm foutherly wind (hould diflblve the clouds
already formed, and the northerly, by their encreafed cold,
fhould produce many more.

Hence electrical agency muft of neceflity be recurred to,
though I do not doubt but it may be more correctly applied by
perfons better verfed in electrical knowledge than I can pre-
tend to be. Currents of air flowing in different directions at
different heights in the atmofphere, mutt undoubtedly be inti-
mately connected with thefe effects, but with thefe we are at
prefent too little acquainted.

4. That a difpofition to rain is generally connected with a The diminilhed

diminution of the weight of the atmofphere, as is a difpofition wei8nt of thf

r -,,.., t, r atmofphere in-

to lerenity with the increafe of its weight. Became under creafes evapora-

the diminifhed weight of the atmofphere, the eruption of va- tlo.n and caufes
pours both from land and water is much more copious, a dif-
pofition highly favourable to nubification, and the clouds al-
ready formed defcend lower, are more concentrated, and
hence more difpofed to react upon and attract each other and
thus produce rain. The increafed weight of the atmofphere
mufl: produce oppofite effects and induce a difpofition adverfe
to the production of rain.

5. That more rain falls on the furface of the earth than on More rain falls
fmall elevations above it, as from 30 to fome 100 feet: fee ^n^tS"1
Phil. Tranf. 1769, p. 361 ; and of 1771, 297; and of 1777, elevations,

p. 256. This effect feems to me to proceed from the greater
ftillnefs and tranquillity of the air near the furface of the earth
than at greater elevations. To prove this, it is only neceflary
to collect the rain that falls in moderate weather on both fitu-
ations, with that which falls on both, in more ftormy weather.
If this explanation be juft the difference between the quanti-
ties collected in both fituations will be found greater in the
Utter than in the former cafe. This experiment I (hall make,
and communicate the refult to the academy.

6. That

124 or rain.

Rain oamoun- 6. That the quantities of rain collected at the (op of high

Iw thra.P,ain' mountains' and on Plains about half a mi,e diftant from tho,e
mountains are nearly equal, but in fummer there falls fome-
what more on the plains, and in winter fomewhat lefs. Phil.
Tranf. 1771, p. 295. The greater quantity of rain collected
in fummer on plains appears to me to proceed from the caufe
juft mentioned, the lefs difturbed flate of the atmofphere; but
the quantity of rain gained through the influence of this caufe
is often, in great meafure, compenfated by that arifing from
the condenfation of fogs formed on the fummits of mountains,
particularly at night, when neither fog nor rain exift on the
plians. But in winter, thefe mifts being much more frequent
and denfer on the fummits of mountains, the quantity of moif-
ture which they depofit is tar more confiderable.
More rain on the 7. That it rains much more on the weftern coafts of moil
wefterly coafts parts of Europe, particularly if mountainous, than in the in-
terior parts of thofe countries, or on the eaftern coafts of the
Britannic iflands.

The caufe of thefe phenomena is very obvious. Wefterly
winds are by far the moft frequent in moft parts of Europe ;
thefe flow from the Atlantic which bounds it, and generally
convey marine clouds electrified differently from the foil or
land over which they flow, as alfo from that of the higher
clouds under which they reign. Hence proceeds their mu-
tual attraction, and thence rain. This effect muft take place
principally on the weftern coafts ; when they proceed further,
this different electrical ftate muft either ceafeor be diminithed.
When the coafts are mountainous, thefe mountains quickly ab-
ford the ele£tric matter contained in the weftern blafts, and by
collifion, condenfe the vapours they contain, firft into clouds,
and finally into rain. Hence it often happens that wefterly
winds, particularly in fummer, produce no rain, either be-
caufe they introduce no clouds, or meet with none differently
electrified.
Countries where 8* That in fome countries it fcarce ever rains. — This arifes
it never rains, from local circumftances, as is apparent in the following in-
Peru. fiances : 1. It never rains on the plains of Peru from the gulf

of Guyaquil, nearly under the equator, up to latitude 23°
fouth, nor is thunder ever heard there, though thefe plains
border on the Pacific Ocean, but they receive a flight dew
every night. Bouguer, fig. de la Terre XXIII. 2 Ulloa*s

Mem.

OF RAIN. 125

Mem. p. 157. 2 Phil. Tranf. Abr. 132. Plainly from the
following reafons : Thefe plains are entirely fandy, and, con-
fequently, emit, very little vapour, being foon parched by the
heat that there prevails ; confequently the intermixture of ma-
rine vapours can produce no effect. -Again, the clouds in
thefe trac"ts are elevated to a great height, and are attracted
by the electrical agency of the Cordellierres that border on
thefe plains, to their lofty fummits, and there produce copious
rains ; hence alfo the fandy and extenfive defarts of Arabia Arabia.
and Africa are feldom refreftied by rain. 2. It fcarce ever Africa,
rains in Egypt, particularly in Upper Egypt. Now it is to Egypt.
be obferved, that Egypt is fo fituated betwixt lofty mountains
that no wind can enter it without paffing over them, but the
northerly winds, which iffue from the Mediterranean ; for a
foutherly wind mull pafs over the mountains of Abyffinia ; an
eafterly, over thofe that intercede between the Red Sea and
the Nile, and proceeding from the Defarts of Arabia, can
convey little or no vapour ; and wefterly winds mull; pafs over
the Defarts of Africa and Mount Atlas. Now the northerly
wind does not begin to blow until the month of June, when
Egypt is fo fcorched as to emit fcarce any vapour, and the few
clouds it may convey are attracted by the mountains of Abyf-
finia. Towards the middle of June the inundation of the
Nile, it is true, commences, and then, as the northerly wind
Hill continues, perhaps rain might be expeded, but little at-
tention being paid to it then, we are not informed whether
any falls or not, perhaps the clouds then alfo pafs to the moun-
tains of Abyffinia, whither this wind conveys them, and which
they deluge with rain ; all other winds depofit their moifture
on the reverfe of the mountains they pafs over.

Prognojlics of Ravi.

When the barometer falls, and the hygrometer rifes, rain is Pmgnoftics of
announced. ram*

When the barometer rifes, and the hygrometer falls, we may
expect fair weather, if farther changes do not appear in thefe
inftruments, as fometimes there fuddenly do.

If the barometer falls and the hygrometer alfo, xvindy wea-
ther will probably follow — particularly if the barometer falls
much below its natural height, which in Dublin is from 29,9
, to 29,98,

Again,

V26

Prognostics of
change in the
barometer.

EXPERIMENTS ON SULPHURIC AC*D.

Again, in the morning the hygrometer is generally higher
than at noon, by reifon of the difference of temperature ; but
if it ftands lower at noon in a greater proportion than the dif-
ference of temperature demands, it prognoliicates fair wea-
ther.— On the contrary, if at noon it be higher than it flood in
the morning, rain may be expected. SaufT. Hygr. p. 356.

To forefee the Rife or Fall of the Barometer in Day-time.

Obferve it at feven o'clock in the morning, and afterwards
at nine and at ten. If it remains fteady, its next motion will
probably be downwards. So alfo if it falls within that interval
of time, the probability is, that it will fink Hill lower. But if
it rifes within that interval, the chances of a greater rife or of
a greater fall are equal.

Again, obferve the barometer at one in the afternoon, and
again at three ; if it remains unmoved, it is probable that it
will rife, but if it has fallen, the chances of a farther rife or
fall are equal.

XI.

Uncertainty in
the analyfis of
pyrites from the
combuftion of
the fulphur.

The burned ful.
phur, or fulph.
acid, precip. by
b-irytes.

Ohfervations and Experiments undertaken with a View to deter-
mine the Quantity of Sulphur contained in Sulphuric Acid ; and
of this latter contained in Sulphates in general. By Richard
Chenevix, F. R. S. and M. R. I. A. (Irifti Acad. 1802.)

IN a paper which I had the honour to prefent to the Royal
Society of London, and the fubject of which was the analyfis
of fome arfeniates of copper, and of iron, I had occafion, in
examining many pyrites, matrices of thofe ores, to remark the
very great inequality which prevailed in the refults of repeated
experiments, made with a view to determine the proportion
of fulphur. But I foon perceived, that the inaccuracy was
caufed by a partial combuftion and acidification of the radical,
through the means of the nitric acid, employed to diflblve the
ore.

Having therefore, in the ufual manner, ascertained what
quantity of that ingredient remained untouched, I was forced
to feek the reft of it in the liquor, which had waflied the va-
rious precipitates. To obtain it, I poured a folution of nitrate

of

EXPERIMENTS ON SULPHURIC ACID. 127

of barytes into thofe warnings, when all the other fubftances
had been carefully feparated, and was thereby enabled to pre-
cipitate, in a ftate of purity, the fulphate of barytes, formed
by that earth, and by the portion of fulphur originally acidified,
in the tirft treatment of the ore by nitric acid. To come at
the knowledge of the proportion of fulphur, contained in a
given quantity of fulphate of barytes, I had recourfe, in the
firft inftance, to the quantity of fulphur, faid by Lavoifier to
be contained in fulphuric acid, and, in the next, to the pro-
portions of the latter, announced in the fynoptic tables of
Fourcroy, as entering into the compofition of fulphate of ba-
rytes. According to the former of thofe chymifts, 1 00 parts Deduction of the
of fulphuric acid contain 71 of fulphur and 29 of oxyg-en; and'^Phubrf"™thc
again, in adopting the proportions of the latter, we have 33 received propor-
per cent, of acid, in fulphate of barytes. But if 100 con- tions did "ot
tain 71 of fulphur, 33 muft contain 23.43. Confequently, for experiments.
every 100 parts of fulphate of barytes, I was to allow 23.43
of fulphur. But, by the refults of my analyfes, I had fuch
quantities of fulphate of barytes, as induced me to doubt the
accuracy of one or other of the ftatements, by which I efti-
mated the quantity of real fulphur contained in the ore.

No perfon is better acquainted than our celebrated prefi-
dent, with the many difficulties that occur in the analyfis of
falts in general ; particularly with regard to the quantity of
real acid they may contain. It has been a work of trouble to
the ableft chymifts, and they have not always agreed in their
refults. The proportions, announced by Fourcroy, may there-
fore be doubted, in common with thofe of the other learned
operators, to whom I have alluded.

The real quantity of acid, produced by the combuftion of The real quarr-
any acidifiable bafis, can be determined by one or other of the *lty of acid
following methods only : by direct combination, in fome fait, ing its radical,
the proportions of which are already known ; or by obtaining, determinable by
in a ftate perfectly free from water, the acid refulting from f°me known fak,
fuch combuftion. To the former method, the general objec- orelfeby obtain-
tions againft all analyfis of falts muft apply. The latter is j^?.** acid dry*
ftill more defective. It is by no means certain, that we have certain from
ever yet obtained any acid, in a ftate of perfect ficcity, unlefs complexity ; the
we except the phofphoric and the arfenic ; for even the cryftal- CafeT impTa°cli-
lized vegetable acids retain a portion of water in their cryftal- cable,
lization. It is not that I abfolutely deny our having obtained

them

128 EXPERIMENTS ON SULPHURIC ACIfir.

them fo ; but I fay merely, that we have no proof. It would
indeed be fetting narrow bounds to the perfection of nature,
to aflert, that no combuftible body could, when faturated with
oxygen, aflume, of itfelf, the ftate of liquidity ; or that the
oxide of the particular fubftance, called hydrogen, muft be
prefent to confer that property. Doubtlefs, fulphuric acid
may, as well as water, contain, in itfelf, fojuft a proportion
of fpecific heat, as to remain liquid at the temperature of our
globe, and under the preflure of our atmofphere. But, both
water and fulphuric acid being eafily volatilized, and having a
powerful affinity for each other, it is noteafy, if even poffible,
by diftillation, to feparate them with fufficient accuracy, in
experiments of delicate inquiry. A fecond fource of error,
therefore, remained open in this branch of the calculation,
which gave the proportion of 23.43 of fulphur, as that con-
tained in 100 parts of fulphate of barytes.
Exp. too fat' However, before I would allow myfelf to call in queftion
fieTbjhitric !" ^ucn authorities as thofe I have quoted, I inftituted the fol-
acid j lowing experiments : In a tubulated glafs retort, I put 100

parts of purified fulphur, and poured upon them ftrong nitric
acid. A quilled receiver, plunging into a Woulfe's apparatus,
was adapted to the retort ; and, all being well luted, I pro-
ceeded to diftil. The liquor, which came over, was poured
back feveral times upon the fulphur, until the whole was dif-
folved. The water, which had come over, and that, through
which the nitrous gas, produced during the operation, had
pafled, were eflayed for fulphureous acid, and no traces of it
could be found. No fulphur had been volatilized; therefore
no fufpicion could remain, that all was not converted into ful-
and theactd phuric acid. The liquors, which were in the various parts of

thrown down tj apparatUc were united ; and to them was added a fuffi-
with nitrate or t r > >

barytes. cient quantity of nitrate of barytes. The whole was evapo-

rated gently ; becaufe, though I am well acquainted with the
very little folubility of fulphate of barytes, I well know that
nitric acid will retain a fmall portion of it, particularly when
Rcfults, that formed in a liquor where that acid abounds. In a firft experi-
phate of barytes ment, I obtained 694 from 100 of fulphur, in a fecond, 348
contain 14.5 from 50, and in a third, 347 from the fame quantity. But
alfo the oxygen. tne nmP^e ruIe of three reduced thefe quantities to 14.6, or
14.4 per cent, of fulphur, contained in fulphate of barytes;
a difference wholly to be neglected. If, therefore we take
2 14.5

EXPERIMENTS ON SULPHURIC ACID. ]^9

H.5 as the average, for the quantity of fulphur contained in
100 parts of fulphate of barytes, we (hall not be far from the
truth. From the accordance of thefe experiments, repeated
and varied, I have now no doubt, but concerning the fource
where I was to feek the error, which gave 23.43 as the juft
proportion. »

To afcertain this point, I operated in the following manner, *• Investigation.
I prepared fome lime, as pure, I believe, as chymical means ha*7 bTLut** f
can procure it. I digefled white marble in muriatic acid j and, marble in mun-
by leaving an excefs of the earth, was certain, that by the atlc fai* tbe"

r i . . . preap. by carb.

fuperior affinity of lime for that acid, nothing elfe had been cfpotajh, and
taken up. Upon trying the folution with ammonia, no preci- w#^a«^
pitate took place. By means of carbonate of potato, I fepa-
rated the lime in the ftate of carbonate ; and, after well wath-
ing the precipitate, expofed it in a platina-crucible to a vio-
lent heat, till the weight no longer diminifhed. I am ac-
quainted with no more efficacious method to prepare lime, fit
for the delicate purpofes of fcientific chymiftry.

One handred parts of this lime were diflblved in dilute mu-II- ioo p. lime
riatic acid, in the fame platina-crucible, previoufly weighed : dl?T ln mur* .

acid, were preclp,

and then fulphuric acid was added in fufficient quantity. Sul- by fulpb. acid, *

phate of lime was precipitated ; and the veflel was expofed to and tlle mar*

l r a i ii- iii ac,c* and water

a heat, at nrlt gentle, to evaporate the liquor ; and then, by driven ofF by

degrees, raifed to a temperature, which could expel every ignition.
thing but the combined fulphuric acid, and leave the fulphate
of lime completely calcined. The crucible with the fait was
then weighed and the augmentation was 76.— It appears to The dry ful-
me, that, if we admit (and I fee no reafon that we mould not Phat? was 7?
admit it) that calcined lime and calcined fulphate of lime are were diyasfcL
wholly exempt from water, it muft be clear, that the 76 addi-
tional weight were fulphuric acid ; and, that the fulphuric
acid muft in this flate, more than in any other, approach
nearer to what may be termed, abfolutely real acid. One
hundred parts of calcined fulphate of lime contain therefore

Lime 57 Component part%

Sulphuric acid 43 £2?***^

100

By the former experiments (thofe made upon fulphur con- III. ioo parts
verted into acid, and then united to barytes) we had the quan- j^' <*
.tity of fulphur, contained in fulphate of barytes. By the folvcd in water

Vol. V.— June. K lattef

]30 EXPERIMENTS ON SULPHURIC ACID*

by the addition latter (thofe made by directly combining lime with fulpburic
of oxalic and acid) we had the proportion of real acid, contained in calcined
acid. fulphate of lime. Confequently, by knowing the ratio, that

fulphate of barytes bears to fulphate of lime, with regard to
the acid in each, we fhall arrive at the knowledge of the
quantity of fulphur, contained in real fulphuric acid. For
this purpofe, I attempted to diflblve, in water, 100 parts of
fulphate of lime. But finding, in this method of proceeding,
a confiderable inconvenience arifing from the great quantity of
liquor, neceffary to effect the folution of that fait, I had re-
courfe to the following expedient. Upon 100 grains of cal-
cined fulphate of lime, I poured fome oxalic acid, which at-
tracts the bafis with an affinity fuperior to that exercifed by
fulphuric acid. Oxalate of lime was here formed ; but oxa-
late of lime is foluble in a very fmali excefs of any acid. A
little muriatic acid operated a complete folution ; and thus a
great quantity of fulphate of lime required but little water to
muriate of ba- diflblve it. Into this liquor, muriate of barytes was poured,
added Threw anc* Offered to remain fome time, gently heated. By thefe
down the acid in means, any oxalate of barytes, that might have been formed,

futph. of barytes was retajne£i -m f0Iution, by the original excefs of acid; and
weighing 1X3. 'jo

This acid was the entire quantity of fulphate of barytes was deposited. Of
known to be 43 the exadnefs of all thefe methods, which I ufed, as the in-
struments by which I afcertained thefe remits, I convinced
myfelf by various preliminary experiments. After the ufual
filtration, warning and drying at the gentle heat of a fand-
bath, I obtained in one experiment 185, in another 183, and>
laftly, in another 180. This difference does not exceed the
limits of what all perfons, converfant in analytic chymiftry,
will allow to experiments of this nature. We may therefore
take 1 83 as the mean proportion ; confequently, we fhall fay,
that 183 of fulphate of Barytes contain the fame quantity of
fulphuric acid, as 100 of fulphate of lime; and 183 : 43 ::
The proportion 100 : 23.5. Therefore 23.5 is the proportion of acid in 100
rntes°is therefore of fulPhate of barytes. But we have before feen, that 14.5
23.5 acid, and of fulphur, acidified by nitric acid, form that portion of ful-
the fulphur in pburic add, contained in 100 of fulphate of barytes : viz.

this, by the firft r * „ r J .

exp. was 14.5. 23.5. We mutt now fay, that 23.5 : 14.5 : : 100: 61.5, and
Real fulph. acid the fourth term will be the proportion of fulphur = 61.5,
Uiph^andt the which combined with 38.5 of oxygen will form 100 of real

reft = 9 o oxi- fulphuric acid.

gen : or 6i£ to Tn

38i=lOO. • m

EXPERIMENTS ON SULPHURIC ACID. 131

In neither of the proportions, whether it be of the acid
contained in the fait, or of the combuftible bafis contained in
the acid, do I agree with the two chymifts whom I have
quoted. This juftly excited fome doubts in my mind, and
led me to repeat my experiments. Nor mould I yet be
thoroughly fatisfied, If I could not, upon other grounds, than
by fuppofing inaccuracy in them, account for the apparent
differences. We muft ever expect to fee the errors of our
predeceffors corrected by men, much inferior in abilities ; but
who, by pofTefling more certain means, fupply the want of
genius and invention. At the time in which the experi- Former experi-
ments were made, that determined the proportion of 33 per ^"J*^^^
cent, of fulphuric acid in fulphate of barytes, it was not known becaufe barytes

that we had never obtained any barytes pure ; and that a con- had not then
/•lit . /. /.« V , «• /• b^en obtained

liderable portion of carbonic acid refitted the action ot every pure>

degree of heat that had been applied to carbonate of barytes.
The fact was, I believe, firft obferved by Pelletier ; but the
method of avoiding the inconvenience was pointed out by
Vauquelin. He decompofes nitrate of barytes by lime, and a
moderate degree of heat is fufficient to expel all the acid and
the water. The chymifts, I have mentioned, performed fyn-
thetic experiments, by combining, directly or indirectly, ful-
phuric acid, and fuch barytes as they imagined to be pure.
The conftant fimilarity of their refults is fufficient to prove the
accuracy of their operations ; but working upon an impure
fubftance, they muft have been contented with a fimilarity of
error.

Three caufes may exift which are capable of accounting and becaufe La-
for any variation, whether in plus or in minus, that might have ^1 \"fPhur \™~
appeared in the experiments, by which Lavoifier determined oxigen,
the quantity of fulphuric acid, obtained by the combuftion of
fulphur in oxigen gas.

lit. A part of the fulphur may be volatilized during com- might have vo-
buftion. lati2td fome>

2d. All the fulphur may not be converted into fulphuric and " mperfedly

•it. '. - . ,. r . . . . acidified fome,

acid ; but part may remain in the ttate or tulphureous acid.

3d. In rectifying, fome acid may come over along with the and been embar-
water; or, vice verfa, fome water remain with the acid. [* IC&\f ying."
Thefe confiderations will excufe me for having propofed a
doubt where the authority of fo great a man exifts againft the
experiments which I have related.

K 2 The

132 EXPERIMENTS ON SULPHURIC ACIt><

Expts. of Taf- The method which I had ufed to afcertain the quantity of
MdrtGIhton!rd, fuJPhurin an ore, had been pradifed by Taflaert, (Annates de
Chimie, No. 82 : Analyfis of Cobelt from Tunaberg) but he
calculated according to the proportions of Lavoiiier and of
Fourcroy. In another paper by Thenard, (Annates de Chimie,
No. 96.) he ftates the proportions of fulphuric acid, obtained
by treating fulphur with nitric acid, to be

Sulphur - 55.56

Oxygen - ... 44.44

100.00

but in the extract given by Guyton in that No. of the Annates
de Chimie, the mode of operation is not defcribed. Calcined
fulphate of barytes is eftimated in the fame paper to contain

Barytes - - - - - 74.82
Sulphuric acid - - - - -25.18

100.00
which proportions are as near to what I had found as can be
expe&eo ; for fulphate of barytes does not contain more than
3 per cent, of water of cryftallization, and they muft be de-
ducted from the quintal.
From the deter- Having determined with accuracy the proportion of acid in
Midam°an0fnS! an? inr°Iubie ^lphate, it is eafy to proceed to the determina-
luble fulphate, tion of that contained in any other fulphate. The docimaftic
it becomes eafy art or anaiytic chymiftry in general, cannot however expeft to
others. derive fuch advantages from the knowledge of foluble falts, as

of thofe, which, from their infolubility, may be ufed with ac-
curacy in delicate experiments to determine the proportions of
the conftituent parts of bodies. But if, with this mode of ope-
rating, we compare the quantities of real acid, faid (in thofe^
excellent tables with which Mr. Kirwan has enriched the fci-
ence) to be contained in fulphuric acid of different fpecific gra-
vities, they will ferve as proofs of their mutual validity ; and
perhaps demonftrate, that fulphuric acid, as well as water,
and fome other bodies, may of itfelf enjoy liquidity, at the
temperature and preflure which aft upon our globe.

SCIENTIFIC

SCIENTIFIC NEWS, 133

SCIENTIFIC NEWS.
Improvement on Lamps.

l\ VERY great improvement in the conftru&ion of lamps New lamp of

and reflectors, has been lately made by Mr. Nicholas Paul Mr* N* Pau1,

of Geneva, who in conjunction with Mr. Smethurft, an

eminent lamp contractor has lately made a public experiment,

by illuminating the upper part of New Bond Street.

. Fifteen only of the new lamps with reflectors, were fub-

ftituted in place of more than double that number of common

ones ; the effect of which was, that the ftreet was enlightened

with at leaft twice the ufual quantity of light.

This effect is produced, not by the combuftion of an extra
quantity of oil, but by the fcientiflc conduction of the ap-
paratus ; the lamp being formed upon the principles of the
beft air furnace ; fo that the whole of the combuftible material
employed, is converted into light and heat, without fmoke ;
and that portion of light which would have afcended and been
loft, is diftributed to thofe fituations where it is required, by
means of reflectors fo formed as to diftribute the fame uniformly
over the illuminated fpace, and to obliterate the fhadow that
would be formed by the body of the lamp.

Thefe lamps and reflectors are not merely adapted to light-
ing the public ftreets, but by various modifications, are ac-
commodated to every circumftance where lamps or candles
can be made ufe of*.

Improvement on the Mode of Watching Cities.

Samuel Day, Efq. of Charter-houfe, Hinton, inrSomerfet- Mr. Day's
(hire, in the commiflion of the peace for the county, has directed watchman'* re-
his attention to the application of a mechanical check upon
the diligence and precifion of watchmen, labourers, and all
other clafles of men, whofe duty requires that they mould at-
tend at certain places at appointed times. His own account
of this interefting arrangement is as follows f.

* I have received the above from Mr. Paul, but expect to give
a fuller account from my own examination, in our next Number.

W.N.

f From a printed paper with which he has favoured me. W» N«

From

134" SCIENTIFIC NEWS

Mr. Day'i From the concurrent teftimony of many Individuals, the

watchman's re- prefent fyftem of watching cities is languid and inadequate :
no houfe is fecure, when depredation is determined on, or if
there be any fecurity, it is more from the means taken within,
than from the watching without. Magiftrates have feen and
pointed out the defects in the fyftem, and have at times ap-
plied what means they could to counteract the evils arifing from
thofe defecls hut their means have been ineffectual : and
householders have been obliged to fubmit to their rifques with
no other confolation but that of thinking, that though the
plan of watching was bad, it was better than none. In at-
tentively considering the plan, the defecls feem to reduce
themfelves to the following heads ; \ft, The too long intervals
which watchmen take, between their going their rounds — by
which it appears that confidering any individual houfe, that
lioufe has not the benefit of actual watching more than ten
minutes through the whole night.

2ndlj/. The Watchman's call of the hours, — from which
no fervice arifes to any, but to the depredators of the night,
as is obvious to any one who reflects, that of the many hundred
housebreakings and ftreet-robberies committed in London in
the year, how few of the depredators are detected or taken
by the watchmen themfelves, from no fault perhaps of thefe
laft, but becaufe the thieves have taken advantage of the
watchman's repofe in his box, and what is more, of the notice
which he gives, by vociferation, of his diftance or approach,
by which they haften, or delay their attack, or carry off their
plunder accordingly.

3dly. The uncertainty of the watchman's doing his duty— -
who either from intoxication, drowfinefs, or indolence, or
induced by the badnefs of the night, may mifs his rounds,
without detection.

$th. The ufe ot he lanthorn, which anfwers no purpofe
but that of adding to the fignal of the watchman's approach.
And laftly the uf< of the watch-box, which anfwers no end
but that of promoting drowfinefs, and perhaps difeafe, from
the chills which are increafed by inaction in a cold damp
houfe.

F<>r thefe defects it will be atked what effectual remedy can
be piopofed ? To double the number of Watchmen would be
the mod obvious, but is out of the queftion when we confider

the

SCIENTIFIC NEWS. 135

the enormous expence which would attend it, and is un- Mr. Day's
neceflfary when we reflect that the ufual number of men em- watchman's re-
ployed, will be fufficient, if any mode can be adopted of fixing
and afcertaining their vigilance. The initrument called the
zvatchman's noctuary, or labourer's regulator, offers a mode for
this purpofe. By one of fuch being placed at each end of a
watchman's round, it will be afcertained how the man con-
tinued his movements through the night, to a nicety of ten •
minutes at any period of the watch — and the flighteft irregu-
larity or omiflion will be vifible the next morning to the in-
fpector or conftable, whofe office it (hall be to open the machine.
The teft of regular and well-fuftained vigilance is given by
the Watchman's dropping a token as he paffes, every half
hour, quarter, or half quarter, into a receiver or cell ; each
half hour or quarter prefenting it's own cell to receive the
fame, and each cell, like time itfelf, irrecoverable when
paffed. No trick or fraud on the watchman's part can
counteract the movement of the horizontal wheel formed of
thefe cells, and completing a revolution once in twelve hours.
He has no command over it, and each cell (as it moves under
the receiver) will be a kind of fpeaking witnefs of his diligence
and fidelity in going his rounds, anfwering the next morning
to the exact periods he either was or ought to have been
there.

By this means the calls of the Watchmen, which were only
militated for the purpofe of his giving notice of being on his
duty, will be fuperfeded ; and a coniiderable expence of animal
exertion will be faved to the individual, which might better
be converted into that of going his rounds twice, where he
now only goes once. Warnings to the nightly thief of timely
attack or retreat will likewife be taken away, and if inftead
of an open the watchman was to carry a dark lanthorn, the
robber would have no fecurity whatever in calculating the
moment of his depredation, and might be detected in the very
outfet of his attack, as the flighteft found would alarm the
watchman walking in filence, and not drowning diftant noife
by that of his own voice.

Of the objections to this new mode of ameliorating the
watching of cities, the only one feems to the expence of the
time pieces, — and confidering the number which the larger
parishes will have occafion for, this expence will be im-
portant ;

136 SCIENTIFIC NEWS.

Mr. Day's portant * ; but let it be confidered that it will not amount t»
w*,tc nian s re" more than three pence in the pound of a rate on houfes, and
that the firft will be the fole expence — probably to be faved by
diminifliing the number of patroles to one half (or lefs) of what
they now are. But trifling indeed will be the expence when
compared with the Iofles fuflained by the public in depreda-
1 tions, which, according to a late work on the police of the
metropolis, amounts to two millions and upwards.

The befl fituation for thefe machines will be at each end of a
watchman's round, perhaps certain rounds will require three.
They ought to ftand in a convenient recefsin the flreet, fecured
by rivetings of iron, or let into a wall, or placed on a ftrong
bracket within the iron railing of an area ; and, if the dial
plates were fuffered to appear, would be ufeful in the day as
well as in the night : as an eight-day clock it would require
no attention to it's movement but once a week, and the morn-
ing infpector might attend to the flight duty of winding it up.

The annual expence of keeping it in repair is too trifling to
be taken notice of.

I have to remark that the fame machine will anfwer in
cuftomhoufes, warehoufes, banking-houfes, docks, and every
place where vigilance, to be ufeful, muft be exacl.

Some Account of a pretended new Metal offered for Sale, and
examined by Richard Chenevix, Esq.
Interefting paper AN extremely curious and interefting paper by R. Chene-
palladium. V1K> Efq, was read on Thurfday the 12th, and the following

week, at the Royal Society. It purported to be an inquiry

into the properties of a fuppofed new metal called palladiuf/i, or

newfiker.
The manner in This fubftance announced to the public in a fmall printed
^ff'adt' T* PaPer> partially circulated, was fold at an extravagantly high
public. price. The notice is as follows ; it is given verbatim, as the

language in which it is written is not unworthy of attention f .

* It is prefumed that each time piece will amount to not lefs than
.twelve guineas, and each round will require two. D— — . I ap-
prehend they may be made for much lefs than half the money.
W.N.

T I received a fmall piece by the poft. The piece of the Ipecimen
was at the rate of about one milling per grain.

PALLADIUM

SCIENTIFIC NEWS. 137

PALLADIUM, OR NEW SILVER,

JIas thefe Properties among others, that Jliezv it to be a new
noble Metal.

1. It diflblves in pure fpirit of nitre, and makes a dark red
folution.

2. Green vitriol throws it down in the ftate of a regulus
from this folution, as it always does gold from aqua regia,

3. If you evaporate the folution you get a red calx that
diflblves in fpirit of fait or other acids.

4. It is thrown down by quick -filver and by all the metals
but gold, platina, and filver.

5. Its fpecific gravity by hammering was only 1 1.3, but by
flatting as much as 1 1.8.

6. In a common fire it tarnifhes a little and turns blue, but
comes bright again, like other noble metals, when ftronger
heated.

7. The greater! heat of a blackfmith's fire will hardly
melt it.

8. But if you touch it while hot with a fmall bit of Sulphur
it runs as eafily as Zinc.

It is fold by Mrs. Fojler, at No. 26, Gerrard Street, Soho,
London, In famples of five (hillings, half a guinea, and one
guinea each.

Immediately on the receipt of this paper, ' Mr. Chenevix Examined by
went to the place where it was advertifed to be fold, and Mr' Chenevi**
bought a piece which he fubmitled to the trials propofed by
the author of the impofition. Mrs. Fofter, it appears, is only
the vender, and totally unacquainted with the perfon who
brought the metallic fubftance and the printed paper to her
houfe

In every refpect but one, the alTertions in the paper
Mr. Chenevix found to cortefpond with his own experi-
ments. The fpecific gravity he found to vary in different
pieces from one to two per. cent.

The refemblance which, in many of its properties, this Sufplcion that It
fingular fubftance bore to Platina, induced a fufpicion in the ™^ontai'1
mind of Mr. Chenevix that the laft mentioned metal formed a
part of the compound, if indeed it was a compound body ;
but the effential characters of difference were fo ftriking and
2 numerous

138

SCIENTIFIC NEWS.

numerous as almoft entirely to remove this doubt, or to con-
vince him that palladium was really a fimple fubftance ; as
its concealed author pretended, and not an impofition upon
the public, as Mr. Chenevix has now proved it to be.
It is platina and It appears then, from Mr. Chenevix's experiments, that
mercury. ^Js pretended fimple metal is a combination of platina and

mercury; and it mtift excite not only aftonifhment, but humi-
lity in the cultivation of natural knowledge, to find that a
combination of two metals, each upon fo high a fpecific gravity
as thole which are combined in palladium, fliould produce a
compound, the fpecific gravity of which is lefs than that of the
leaft weight of the component fubftances ; and, moreover,
that mercury whofe affinity for caloric had hitherto been
found to baffle all attempts to deftroy its volatility ; could,
when combined with platina, become as fixed as any metallic
fubftance, with which we are acquainted. But nature laughs
at our theories, and forces us from time to time, by extraordi-
nary difcoveries of this fort, to acknowledge that we are her
vaflals, and that we drive in vain to bring her within our
laws.
Procefs for com- Without entering into any detail of the contents of this
pofing it. paper, which is interesting in many other refpects, as well

as in the difcoveries which it announces, we fhall fliortly
ftate one of the means, feveral being given, by which
Mr. Chenevix accomplishes the production of palladium ;
or, at leaft, of a fubftance having every chemical or phyfical
property of that fuppofed metal. He diflblves platina, pro-
cured from the ammoniacal fait, in nitro muriatic acid. To
this he adds twice its weight, at leaft, of red oxide of
mercury, but if the acid be not faturated he adds more till the
whole liquor is perfectly neutralized. This combination of
muriate of platina and mercury, is then to be poured into a
folution of green fulphate of iron, and the black metallic
precipitate which is thereby formed is, when collected, and
the excefs of mercury driven off, at a red heat, fufed in a
Black's furnace. It melts into a metallic button at a white heat,
and becomes palladium ; a compound as it feems, of two
parts of platina to one of mercury.
Variations in Mr. Chenevix finds it difficult always to combine with

ccompoun . pjatjna ^g fame qUantity 0f mercury; and the fpecific gravity
of his palladium varies like that which is fold by Mrs. Fofter ;
4 but

SCIENTIFIC HEWS. 1J9

but he has found, when the experiment completely fucceeds,
that palladium, containing one third of mercury, is of the
fpecific gravity of 11.5,— when it contains one fourth of that
metal, the fpecific gravity is one part higher ; and the higher
the fpecific gravity, the greater is the proportion of platma,
and the lefs the ductility of the compound. Above 12.5, it
fo far ceafes to have the properties of palladium, that it is no
longer foluble in nitric acid.

The remaining particulars of this highly interefting paper
we muft defer till after its publication by the Royal Society.

A new Method of Painting, propqfed by M. Carbonell, a
Spanijh Phyfician, capable of being advantageoujly fubftituted
for Painting in Diftemper *.

THE difagreeable fmell perceived on entering rooms newly Bad fmell of
painted in7 diftemper is univerfally known. It is only after Pj£"J£« in dIf-
having left thefe rooms expofed to the action of the air, that
they are habitable. A procefs which remedies thefe two in-
conveniences, deferves therefore to be adopted, and it is with
that view that we infert that lately publilhed by M . Carbonell*
a Spanifh phyfician.

The mode of operation, defcribed by the author, is very Simple procefs
fimple, it confifts in fubftituting the ferum of the blood of ferum 0°f blood
oxen, inftead of the folution of glue commonly ufed to mix up infteadof fizej
the colouring matter.

To fucceed, the following methods mufl be ufed :

lft. The butcher muft be directed to receive the blood of
one or more oxen in proper veflels. When the blood is quite
cold, that is to fay three or four hours after it is drawn, the
veflels muft be gently inclined, by which means, a clear, am-
ber-coloured liquor will be decanted. This muft be pafled
through a ftrainer to feparate the fragments of the clot which
have broken off and been mixed with it.

2d. Reduce to powder quick-lime, which has been fprinkled with flaked
with a little water to diminilh the adhefion of its integrant
parts. Pafs this powder through a fieve, and depofit it im-
mediately in boxes or bottles well clofed.

* Bibliotheque de Sonini, No. V.

3d. When

140 SCIENTIFIC NEWS.

Manner of ufmg 3d. Wheg thefe two materials are to be ufed, the ferum iV

it, &c. fir ft poured into a wooden or earthen vefTel, and mixed with

a fufficient quantity of the lime, pulverized as directed above,

taking care to preferve the mixture of a proper fluidity to be

eafily Ipread with the brum over the furfaces to be covered.

4th. Too great a quantity of this paint mull not be prepared
at once, becaufe it thickens very faft, and when it has acquired
too much confidence it cannot be ufed. This inconvenience
may, however, -be remedied by keeping the fluidity at the
fame point, by the addition of a fufficient quantity of ferum,
which fhould always be kept in a veifel near that containing
the paint, that it may be ufed when neceflary.
Addition of co- 5th. The colour fo prepared, fhould be ufed as quickly as
lour. poffible.

General re- 6th. As the colour refulting from the application of this pre-

roarks. paration is always white, and as there are circumftances in

which a different colour is wifhed for, this may be obtained,
by adding a bolar earth of a red, black, green, or yellow fpe-
cies to the ferum, at the fame time as the lime is mixed. Even
a beautiful blue may be obtained by ufing the blue glafs pre-
pared from oxide of cobalt, provided it be reduced to an im-
palpable powder.

7 th. The ftrength of the compofition being neceflarily lef-
fened by the addition of the bolar colouring matters, the fame
degree of folidity may be preferved by adding to the ferum
ufed for diluting this compofition, a few whites of eggs ; but
particular care mufi be taken not to put too many, otherwife
the paint will be fubjecl; to fcale off.

8th. This paint can only be applied on wood-work or coat-
ings of plafter, which have not been previoufly covered with
oil-paint.

9th. As one layer will not be fufficient, two or three may
be laid on thofe furfaces which are required to be well painted ;
but before laying on a fecond coat, that which has been al-
ready applied mull be perfectly dry.

lQlh. A beautiful polilh may be given to this paint by fric-
tion, in the fame manner as to other forts of paint ; it need
only be obferved, that it is better to greafe the cloths ufed for
rubbing it, with clear whale oil, rather than with any other
kind of oil.

11th. To

SCIENTIFIC NEWS. \^

11th. To temper this paint whether white or coloured, it
is neceflary that the ferum -fhould be frelh and not have under-
gone any change, otherwife the paint will be of a bad quality
and not durable.

The prefervation of the ferum, particularly ii> the fumraer,
requires much caution, becaufe this fluid has a great tendency
to putrefy. It is therefore eflential to keep it in a cool place,
and to examine before ufing it, whether it has begun to emit
a bad fmell ; for, in that cafe, care mull be taken not to ufe it.

For the fame reafon the veiTels in which the ferum is kept
muft be carefully cleaned, and warned frequently with hot
water, to remove the fpoilt portions of this fluid, with which
the pores of the vefiels might be impregnated. !

M. Carbonell aflferts that this paint is fo durable, that when Very durable.
prepared with good materials, it may be ufed to paint the
walls of damp houfes, without fear of its coming off; an ad*
vantage certainly not pofleflbd by difiemper painting.

The fame author alfo afferts that he has made many experi-
ments with this fame paint, and has obtained fatisfaclory re-
mits ; and in all cafes fo conftant, that he doubts not, when
it mall be known, that it will be generally adopted. He in- May be ufd in
ftances, among other examples, the ufe which is made of it out-door work,
at Barcelona, as well in the exterior of buildings as within-
fide, and he has always obferved, not only that the fun, the
air, moifture or drought, produce no change on it, but alio
that it is free from bad fmell ; fo much fo, that places where it
has been ufed may be inhabited without danger the very day
of its application.

One might be difpofed, at the firft glance, to believe that It is verydif-

the new paint propofed by M. Carbonell, is nearly the fame fere,nt trom the

; t » r -ii i ,- i i r i *&> ^ ■. m'lk paint,

with that or milk, detcnbed iome years ago by Cit. Cadet

Devaux, This latter paint may alfo have fucceeded ; but on
reflecting upon the eflential difference which exifts between
the ferum of the blood and that of milk, it will foon be per-
ceived that if the milk paint is good, that of M. Carbonell mull
be better.

But experience muft decide in this refpecl, and it is to be
prefumed that a fnort time will make known which of the two
methods deierves the preference.

The work in which M. Carbonell has given the details re-
lative to the preparation and ufe of his paint with ferum, is

dedicated

1 J42 ' ACCOUNT OF NEW BOOKS.

dedicated to the queen of Spain. This work has been printed
in the Spanifh language : it would be very worthy of being
tranflated into French, which would be the means of giving it
greater publicity.

ACCOUNT OF NEW BOOKS.

North London Rep0rt 0f the intended North London Canal Navigation ; with
general EJlimate, Sfc. fyc. By R. Dodd, Engineer.
1802. p. 23 Quarto.

Ti

HE line of this intended canal is to communicate with the
Thames near Bell-Wharf, and, paffing through Ratcliffe and
Whitechapel, is to join a bafon near Hackney turnpike,
from which the the main line is to extend to the river Lea
near Waltham Abbey, Two collateral cuts are alfo to be
continued from this bafon for the convenience of the eaftern
and northern fuburbs of the city. From Waltham Abbey
the river Lea is to be navigated as far as Bifhop's Stortford,
at which place the intended line will again commence and be
continued until it forms a junction with the Cam below Cam-
bridge, From thence that river is navigable to the wafh or
Lynn deeps.

The advantages to be derived from the propofed meafure
are numerous, whether confidered as facilitating the con-
veyance of provifions to the capital ; as furnithing a fafer and
cheaper communication from the wharfs and warehoufes at
the eaftern extremity of the town, to the northern and weftern
parts of it ; as leflening very much the diftance and danger
of water carriage between the metropolis and the whole of
the eaft coaft ; or, as affording the government a ready means
of tranfporting troops and military ftores in the event of an in-
vafion of that part of the Iiland. «

The general advantages of Canals as well as thofe peculiar
to the prefent ftatute are ftated with confiderable perspicuity
by Mr. Dodd in the prefent volume.

Defcription

ACCOUNT OF BOOKS. 143

Defcription of an improved Armillary Sphere exhibiting at one Pattrlck on the
View the true Solar, or Newtonian Sj/Jlem, agreeabty to that armilIary fPhere»
Order, Harmony, Beauty, and Variety obfervable in the Hea-
vens; whereby the Science of Ajironomy Will be familiarly ex-
emplified. By T. Pattrick, Optician, and Manufacturer of
Adam's and Senex's Globes, No. 29, King Street, Co vent-
Garden, 1802. pp. 24. \2mo.

THE patent nautical angle, whereby a fhip's departure, on the nautical
meridional difference of latitude, &c. are obtained fromin-ans *
fpe&ion, with the greateft accuracy, in plain failing, oblique,
current and mercator, with a Hiding fcale of meridional .
parts, graduated to four miles. By the fame author, 1 803,
pp. 19. 12mo.

Theorie des Vents et des Ondes : A Theory of the Winds and
Waves, by M, de la Coudray. 1 Vol. in 8vo. Price 3
Francs. Bernard, Paris, 1802.

Expofe des Temperatures ; An Account of Temperatures, in
which the various ftate of the atmofphere, and the influence
of the air on the human frame, animals and plants, are
treated on in the way of aphorifm. Price fewed, 5 Francs.
Barrois, Paris, 1802.

De V Eleclricite Medicate : A Treatife on Medical Electricity,
by Cit. Sigaud Lafond. Profeflbr of Natural Philofophy
and Chymiftry, in the Central School of Chers. Affociate
of the National InfHtute, &c. 1 Vol. 8vo. 618 pages,
with plates, 6 Francs fewed. Delaplace, Paris, 1802.

Nouveaux TraitS fur la Confiruclion et Invention des nouveaux
Barometres, Thermometres, Hygrometres, Aereometres et autres
Decouvertes de Phyfique Exptrimentales : A Treatife on the
Conftruclion and Invention of Barometers, Thermometers,
Hygrometers, Areometers, and other Difcoveries in Ex-
perimental Philofophy, by Affier Perricat the Elder, Engi-
neer, &c. : with Meteorological Obfervalions made on the
Mountains by many learned Men, and by the Author him-
felf, with comparative Tables. 1 Vol. Svo. Price 2 Francs,
10 Cents. Paris, 1802.

Traiic

|4,£ ACCOUNT OF BOOKS.

New Books; Traite d'Optique: A Treatife on Optics, anew Edition revifed
and corrected, with Additions, particularly on the Produc-
tion of the Images in Optical Inflruments, on the Achro-
matic Telefcope, and on the Iris, by many Pupils of the
Polytechnic School, with all the Plates of the old Edition,
and the Addition of many new Ones, by Lacaille. 1 Vol.
8vo. Price 3 Francs.

Nouvelks Experiences Galvaniques: New Galvanic Experi-
ments by Nyften, Phyfician, 8vo. Price fewed, 2 Francs.
50 Cents. Levraults, Paris.

URNAL

OF

NATURAL PHILOSOPHY, CHEMISTRY,

AND

T H E ARTS.

JULY, 1803.

ARTICLE I.

On the Naturalization of Plants. By John TempletoN;
A L. S. From the Iri/h Tranfadions, Vol. VIII.

1 HE naturalization of plants is an object of fuch importance, Naturalization
and a fubjea that is at prefent fo little underftood, that any ^^"Jj"1*
attempt to extend our knowledge of it, however trifling, may
/till tend towards improvement, and perhaps ferve as a foun-
dation, on which at fome future period a more perfect ftruciure
may be erecled. Many experiments are yet wanting, much
remains to be yet done, and, like other branches of know-
ledge, it will require the united efforts of numbers to bring it
to perfection.

The fame Almighty hand that formed the earth, has feat- though highly

tered in far diftant regions vegetables which the neceffity or b«nefictel »
, r -. i • i i • / countries.

ruxury or man excites him to endeavour to accumulate about

his home. And if we at the prefent time furvey the different
nations of the earth, we will find that mpft of them have re-
ceived great and important benefits by the introduction of
foreign plants ; and that there is no country, however nume-
rous its collection of plants, but may yet receive confiderable
advantages by the naturalization of others.

Botany, a fcience which every one engaged in the fhidy of Particularly t«
Will readily acknowledge to afford one of the pureft of human the ******

Vol. V.—July. L pleafurea,

14$ ON THE NATURALIZATION OF PLANTS.

pleafures, from the introduction of exotics derives its principal
fupport; and certainly whatever tends to facilitate this amiable
fludy is truly deferving of the attention of every philanthropic
mind. As all botanifts cannot have an opportunity of ex-
amining plants in their native foils at proper feafons, it is there-
fore only by tranfplanting and cultivating, they can become
acquainted with the productions of diftant countries; and to
cultivate them with fuccefs we mult derive our information
principally from the plants tbemfelves : each has certainly a
peculiar character, which were we truly acquainted with,, thofe
tedious experiments with each newly acquired fpecies, which
now nearly exhauft the patience of all lovers of plants, would
be no longer necefiary ; gardening might then boaft of being
eftablithed on fcientific principles, and would then never adopt
rules contrary to what nature dictates.

Nor will the, fcorning truth and tafte, devote
To ftrange and alien foils, her feedling ftems j
Fix the dark fallow on the mountain's brow,
Or to the mofs-grown margin of the lake
Bid the dry pine defcend. From nature's laws
She draws her own : nature and flie are one.

Mason's English Garden, B. Ill, line 226.

By our prefent imperfect knowledge of the phyfiology of

plants, we are neceffitated to accept of every affiftance within

our reach : and plants being fo immediately connected with

every modification of the atmofphere, meteorology, which has

hitherto been conlidered as an object of curiofity, is a fource

from which we may derive much ufeful information.

The mean heats Heat being found to increafe or decreafe nearly in a regular

of different ch- progreffion, according to the degrees of latitude, if the latitude
mates confider- r _ » ' . b . . . h . , , , ....

ably govern their or the place where a plant is round be known, by conlulting

vegetation, ]yfr, Kirwan's table of the mean annual temperature of dif-
ferent latitudes *, we may find whether the temperature nearly
correfponds with our own. Or, fuppofing the mean annual
temperature of Dublin, lat. 52°, equal 50 of temperature, by
adding one for every degree of latitude fouthward, and fub-
trading one for every degree of latitude northward, we have
the temperature correctly enough for our purpofe. For thefe

* See an eftimate of the temperature of different latitudes by
R. Kirwan, Efqj page 17.

2 calculations

i

ON THE NATURALIZATION OF rLANTS. 147

calculations need not be carried to the greateft degree of cor-
rectnefs, as we know that, if we except a few, plants have a
contiderable range of latitude ; thofe which cannot bear froft, but with con-
being found to extend from the northern to the fouthern verge fud^rable latl"
of the torrid zone, and many of thofe which grow on the
fouthern limits of the temperate, to approach the borders of
the frozen zone. Thus of the Lapland plants near three hun*
dred are found in the environs of Paris *, many of them much
farther fouth, and fome, as the water lillies (nymphaa) , fundew
(drofera), arrow-head (fagittaria), &c. even natives of India f .

In the latitude 44-° on the European, and 34° on the Ame- plants do greatly

rican continent J, it is not unufual for water to be frozen in accommodate
T * r r r i r i themfelves to th«

January; and as lome iealons are much more levere than Cnmate.

others, plants growing confiderably farther to the fouthward

would be liable to fufFer by cold in fuch feafons, if nature had

not provided a remedy by their manner of growing, which

enables them to refift the cold of fuch rigorous feafons; and

on this account many of them will be found to thrive, when

tranfplanted nine or ten degrees further north than their native

jftations.

From ancient authors it appears that Italy formerly expe- Inftances in the
rienced the fame degree of cold as the American continent 3ncien* and Pre*
under the fame parallel of latitude does at prefent. Therefore Italy*
it is highly probable, that Italian plants not introduced into
Italy fince that time, might in a feries of years be changed
from their now tender to their once hardy Hate.

But in conducting fuch an experiment as the naturalization
©f plants from a fouthern to a northern climate, fo many mi-
nute circumftances require our attention, that few people have
either time or patience to reach the withed for goal.

But a careful attention to the characters which the plants
themfelves prefent, will enable us to proceed with more cer-
tainty, and hopes of having our endeavours crowned with
fuccefs.

By the appearance of the roots and leaves we may nearly In naturalizing

determine in what kind of foil the plant is raoft likely to thrive. piants. Partici*r
^ , _ r J attention muft be

Kobuft roots and flefhy or rigid leaves require a dry foil, ac-paid to the foil.

* See Flora Lapponica & Thuillier's Flore des Environs de Paris,
f See Hunters Evlyns Sylva, p. 552.

J See Kirwan on the Temperature of different Latitudes, p. 50.

L 2 wording

148 ON THE NATURALIZATION OF PLANTS.

Inftruftioui. cording to their thicknefs; ftirT clay or fandy loam, as beans,
peach, and apple trees; robuft fpongy roots which have a
tendency to mat near the fur face with thin leaves, as the alder
(betula dims), willows (falix), require a fomewhat (tiff foil
with moifiure ; many of the falix genus will not grow with
their accuftomed vigour, in a light turfy or peat mold foil, for
want of the neceflary refiftance to the roots, although fuitable
in refpect to moifiure. Slender, hard and wiry roots, as thofe
of the pine, ciftus, &c. require dry, fandy, or gravelly foils.
And extremely fine and hairlike roots, as thofe of erica, hal-
mia, rhododendron, &c. muft have a foil whole particles will
not impede the (hooting of their tender fibres, and with a fmall
but regular degree of moifiure, that the roots, which by their
form cannot refill: the flighteft drought, may not be deflroyed.
Plants in a warm climate perfpire more than in a cold one ; fo
in a warm they require much, and in a cold one little moifiure.
Therefore, when tranfplanled from a warm to a cold climate,
they mould have a dryer foil, and from a colder to a warmer,
a moifter one, than their native ftation.

In tranfplanta- In the firft cafe, not being able to perfpire the fuperabun-

tion to a cold Jant moifiure, they will be rotted : and in the Iaft, not having
climate the foil .. . _ * J . • ; •■ ' , ,-■ • i 7

muft be dryer; moiiture iuflicient to lupply the lots by perlpiration, the growth

and the contrary. wiH be flow, difeafe and death will follow, unlefs they receive
a timely fupply of moifiure : by the red or yellow colour of
the leaves we may difcern the approach of the firll evil, and
by the flunted growth, and fmall curled leaves, that of the
laft. A large quantity of pure circulating fluid feldom injures
plants, but flagnant water is certain deftru&ion to almofl every
vegetable.
Local fibration After having determined the mod fuitable foil, we muft
or expofureisof afterwards ftrive to give each plant a proper fituation. It is
auence. we^ known, that plants from a fhady will not thrive well in

an open, nor plants from an open in a fhady fituation. But
the neceffity of a natural fituation is by no plant more evidently
illuftrated than by the common myrtle (myrtus communis),
Even at Glenarm, in the latitude 54° 56' N. it grows with
great luxuriance contiguous to the fea, and braves our coldeft
winters ; yet all attempts to naturalize it in an inland fituation,
feveral degrees farther fouth, and in a much more genial cli-
mate, have hitherto proved unfuccefsful. The olive tree

cannot

ON THE NATURALIZATION OF PLANTS. 149

cannot poffibly be cultivated in the interior of Afia or Ame-
rica, though the latitude be in other refpe&s favourable, nor
is it fruitful when excluded from the fea breezes *.

The caufe of this may be that near the fea th« temperature The myrtle
is more regular than within land, and fudden changes we pcr^ J j^V "J^JJJ
haps unfavourable to evergreens: for we always find thofe the temperature

with broad leaves grow beft in the made, and thofe with nar-Xf"* ,efs* .

6 ■ . Other remarks,

row leaves on elevated places, in both of which fituations the

temperature is more regular than in open expofures or confined
vallies. And we may often obferve plants growing on a fome-
what elevated fituation, if fheltered from ftrong winds, lefs
hurt in a fevere winter, than others in low warm and fheltered
places. For vapour being railed in fuch places during the
day, produces a greater degree of cold by condenfation and
evaporation in the night, than is experienced in other places
where the coldnefs of the air prevented the rife of vapour
during the day. From every obfervation it appears, that thofe
plants which have the leaft lap in winter, or whofe fap is of a
refinous or oily nature, fuffer lead from cold, and that the
principal caufe of deftru&ion is the veflels being burft by the
freezing of the fap. The hoar-froft, which is always mod
abundant in vales, tends in a great degree to promote this ;
for being changed into water, part only of this water is eva-
porated during the day, the reft remains to be converted into
ice by the cold of the enfuing night. This icy covering en-
creafes the cold, till the vital principle +, and refi ft ance given
by the formation of the bark to the entrance of cold, are over-
come, the fap frozen, and at the fame time the veflels burft
by the expanfive force of freezing. This gives the reafon
why plants in a fituation where the fun does not thine on them
to thaw the hoar-froft, fuffer leaft in fevere feafons ; and that
plants removed in autumn, unlefs the (hoots are completely
hardened, will be more liable to be injured by froft than thofe
of the fame fpecies, the defcent or fixation of whofe fap has
received no check by tranfplanting. Miller remarks, that
thofe plants which were removed in the autumn of 1739, were

* See Saint Pierre's Studies of Nature, tranfiated by Hunter,
Vol. I. page 607. Dublin edition.

f See Smith's Trails relating to Natural Hiftory, page 177, and
Philofophical Tranfa&ions for 1788.

moftly

J50 ©N THE NATURALIZATION OF PLANTS.

mofily killed by the cold of the enfuing winter, while many
of the fame fpecies efcaped uninjured : and the fame may be
always obferved after every fevere winter *.
Sun/nine and Few deciduous fhrubs agree with (hade ; their natural place

is the funny ontfkirts of the foreft; and when otherwife fituated,
long and flender branches, with large thin leaves, fhew their
unhealthy flate. From thefe the climbing plants are eafily
diftinguilhed by their tendency to contortion, or (hooting forth
roots or tendrils. To the deciduous climbers a flight (hade is
not hurtful, as it is only there they can find the neceflary fup-
port ; but in the deep recefles of the foreft, the evergreen
climbers will fpread around their tangling branches, and thrive
with wild luxuriance,

Where fcarce a funbeam wanders through the gloom.

Thomson's Seasons.

never appearing, if the foil is fufficiently moift in fummer, to
be hurt by the thicken1 (hade of deciduous trees,
fhade defends The (hade is alfo the natural fituation for young plants. By
plants from froft. the parentai ftiade they are proteded from the drought of fum-
mer, and the cold of winter. The more a plant is (haded in
winter, and the nearer it is to any large body, the lefs danger
it will be in of fuffering from froft. For when a plant or water
is fo fituated as to be overtopped by trees, a great part of the
hoar or frofty particles, which would fall on it, is intercepted.
Under trees we may often obferve water unfrozen, and plants
unhurt by the feverity of cold, and many retaining their leaves ;
when water at a fmall diftance is frozen, and plants of the fame
fpecies, but unfliaded, lofe their leaves and furTer confiderably.
As large bodies are not eafily cooled, the cold is in Come de-
gree mitigated by the items of large trees. That this is the
cafe maY be perceived, the twigs and fmaller branches being
covered with hoarfroft, when the trunk and larger branches
remain uncovered.

* The following experiments may throw fome light upon the caufe
of plants remaining unfrozen, when the furrounding water is frozen.
Water enclofed in fcaled glafs globules remains unfrozen, till the
thermometer defcends to twenty-four ; unfealed ones freeze and
burft immediately on being cooled down to freezing water. Oil
enckild in the fame kind of globules continued unexpanded, and
confequently the globules unbroken, when placed in a mixture of
foow and fal ammoniac, and cooled below o,

Dr,

ON THE NATURALIZATION OF PLANTS. 15 1

Dr. Wilfon of Glafgow obferved, that when a great degree Remarkable
of cold prevailed, palifades extending outward from a houfe, 1^^"^ 0f e
and alfo from a large pillar, were covered with hoarfroft, in froft on infu-
the mod regular manner, according to their proximity or dif- lated bodies.
tance from the houfe or pillar, thofe next the houfe or pillar
remaining free from hoarfroft, while the more diftant ones
were entirely covered *. This accounts for the fig-tree moots,
mentioned by Miller, being killed when growing out from the
wall, at the fame time when the other (hoots clofe nailed to it
efcaped unhurt f . From this circumftance, moft people have
affixed thofe plants which they with to naturalize to the cli-
mate againft walls. But when put to a wall, care fliould be
taken that they are fheltered from ftrong winds, which gene-
rally injure the leaves and young (hoots, thereby deftroying
the plant if it is not vigorous. On this account the flems of
large trees are preferable for climbing plants, and there they
muft always be more admired as appearing more natural.

But in/lead of affixing to walls thofe plants which require no
fupport, we might cultivate them in pots or boxes, which may
be placed in their proper expofure during the fummer, and,
until their hardinefs is determined, removed under the fir or
other trees in winter, the thicknefs of whofe (hade ought to be
proportioned to the apparent tendernefs of the plant.

Thefe pots or boxes (hould be always funk in the earth, and
in winter the furface covered with mofs. The drier the ground
the better, for funken pots are liable to be too damp.

The beft manner of treating ericas is to place them in a Treatment of
proper fituation in the fpring, and on the approach of fevere e"cas andothcr
weather to fix branches of fpruce-fir about them, augmenting
the covering as the cold encreafes. But as the cold feldom
becomes fuddenly fevere, and a (light froft does them little in-
jury, the erica tubliflora, one of the moft tender, bearing about
29° of Fahrenheit's thermometer ; it is beft not to begin cover-
ing too foon, left, as they are plants that require a very (mall
degree of heat, they mould be made to (hoot, in which cafe
the (lighteft froft will perhaps detlroy them. To protect her-
baceous plants from froft, mofs is the moft proper covering, by
remaining alive through the winter; even after being pulled
up, it is not liable to heating and putrefaction, as all dead ve-

* Philofophical Tranfaaions, Vol. lxx. p. 471, 2.
f Miller's Dictionary, Article Ficus.

getable

15? ON THE NATURALIZATION OF FLANTS.

getable fubllances are, by which they impart to the plant heat
and moifture (the two principal agents which caufe vegetation)
thereby putting the vegetating powers in action, and filling
the plant with fap, at an improper feafon. In our culture of
annuals our only care is directed to placing them in proper
foils and expofures. For, that no region of the earth fliould
remain uninhabited, with a liberal hand have the annual plants
been diftributed ; from thefe do men and animals derive their
principal fupport, and of all the vegetable kingdom, they are
bell adapted for naturalization. By bringing their feed to per-
fection in a fingle feafon, they are capable of cultivation in a
greater variety of climates than any other vegetables, And
the feed, being equally undeftroyed by natural heat and cold,
lies dormant, till genial weather calls forth its latent powers,
and urges it to vegetation, whether among the frozen fnows
of Siberia, or the burning fands of Africa. The refeda odorata
(mignionette), a native of Egypt, and helianthus annuus (fun-
flower), of Mexico and Peru, ripen their feed, and are thereby
perpetuated in our northern latitudes. St. Pierre * fays, the
peafants of Finland cultivate tobacco (nicotiana tahacum) , with
fuccefs, beyond the fixty-firft degree of latitude; and that
barley fucceeds in the very bofom of the north. Amidft the
rocks of Finland he faw crops of this grain as beautiful as ever
the plains of Paleftine produced f.
Criterions by When we endeavour to naturalize plants, that we may dif-

exo't cs may be ^inguim thofe which offer the fairefi profpect of fuccefs, a
diftinguifhed. comparifon of the exotics with the natives of the foil will be
our furefr. guide. Thus we find, that throughout the frofty
regions of the north, the trees, Ihrubs, bulbous and perrennials,
complete their (hoots, and, before the cold of the winter com-
mences, enclofe in hybernacule or fcaly buds, the embryo for
the coming year. And there is every reafon to believe that all
exotics will ceafe growing, and form thefe buds or hybernacule
in the open air during the courfe of our fummer, will not fufFer
from the feverity of our winter. In the hot-houfe many plants
complete their (hoots that would not probably do fo in the
open air, the heat not being fufficient to caufe them to grow
with the vigour neceflary for their completion before winter.

* See St. Pierre's Studies of Nature, tranflated by Hunter, Dub-
lin edition, Vol. I. page 604.

f See the fame Work, page 667.

Neverthelefs

ON THE NATURALIZATION OF HANTS, J53

Neverthelefs many of thefe, if not all, might be brought, by
enuring them to the open air, to bear our climate. The ca-
melia japonica, thea viridis, and calycanthus praecox, which
were formerly kept in the hot-houfe, then in the green-houfe,
are now fufficiently naturalized to grow in the open air, and
are as little injured with the cold of our winters as either the
common or Portugal laurels.

Some exceptions to this obfervation feem to prefent them- Exceptions to
felves. The robinia pfeudo acacia (two-thomed acacia) does •■ ru,e*
not form external hybernacule, nor complete its (hoots, yet
grows well in our climate ; it however, when the froft comes
on early, lofes a great part of its fummer (hoots. Several fpe-
cies of the ciftus, that ceafe growing on the approach of winter,
but form no hybernacule, live through our mild winters, but
iuifer greatly in fevere frofts. And others, as the lauruftinus
(viburnium thus) continue to (hoot and flower, unlefs the froft
is fevere throughout the winter, fuftained by their vitality, or
that principle whofe exiftence preferves plants unhurt by cold
before flowering, but which ceafes to exift when the parts of
fructification have performed their office *.

The lauruftinus is one of thofe plants that were introduced On thelaurufti.
to Ireland before green-houfes were known, confequently n,u*' J?uddl,e* ,

, , , . .. rt . . . ' , . / globofa and fuf.

planted in the open ground, and experience (hews that it is chia coccinea.

feldom hurt by froft. By it we find that fome plants, which
to appearance are not fitted for our climate, do yet outlive our
winters ; and that, without a knowledge of their native ftations,
we may fometimes fuppofe plants to be tender which are really
hardy : thus the lauruftinus is unhurt by froft in Ireland until
the cold exceeds that of its own climate. The buddlea glo-
bofa and fufchia coccinea are other inftances of plants, that
without a knowledge of their native climate, Chili, we would
not fuppofe capable of being naturalized to ours. Yet is the
buddlea feldom injured by our cold, and the fufchia, although
killed to the ground by the winter's cold, fends forth abund-
ance of (hoots which attain the height of three feet in fummer,
and are decorated with its elegant flowers, which are larger
and much more brilliant than ever they are when confined in
a houfe.

* See Smith's Tra&s, page 177, and Philofophical Tranfaaions
for 1788.

And

|54« OI* THE NATURALIZATION OF FLANTS.

The plants of And there is a little doubt but many plants of Chili, and even
elevated tropical (j10re wnjch grovv yvithifl the tropics, when found near the ele-
endure the cold vation of perpetual froft, would bear the cold of Spitzbergen ;
of the higher for on the tops of mountains are found the plants of the plains
of more" northern latitudes. Thus is the falix herbacea of
Lapland and Spitzbergen found on the lops of Mourne moun-
tains at about the elevation of 2,500 feet. On the Serra of
Madeira, latitude 32°, 38', and elevated 5,162 feet, is found
the erica arborea, of the neighbourhood of Genoa, latitude
44°, 25' *. Therefore as the temperature which prevails at
the elevation of 5,162 feet, in latitude 32°, is found nearly to
correfpond with that of 51° north : the erica arborea, which
grows at that elevation in latitude 32°, will find a climate
fuited to its nature in latitude 51° f. But as the before men-
tioned plants have a confiderable range of latitude, it may be
cultivated farther north when the foil and lituation are favour-
able. At James Holmes's, Efq. on the eaftern fliore of Car-
rickfergus Bay, four miles nortij of Belfaft, there is a plant in
the greateit vigour at the prefent time (July 1799) which has
now flood uninjured three as fevere winters as Ireland ever
experienced, viz. 1794, 5, 1797, 8, and 1798, 9%.

The lituation is however favourable, being again ft a weftern

wall facing the fea, and well (heltered by diftant trees from

ftrong winds. And in the neighbourhood of the fea I have

little doubt but it would grow lull farther north.

The fea air is The fea air has generally been reckoned a powerful obftaclc

affirmed to be no to j]ave plantations on its fliores. But many obfervations hav<
obftacle to plan- r ... • , , , . ,

tations; but that convinced me that it is the wind alone which prevents th<
the open expo- growth of trees on the (bores of the fea. Aud that on a large
pernicious. plain, where the winds are unimpeded in their courfe, the

fame difficulty of raifing plantations as on the margin of the

ocean will be experienced.

' * See Sketch of a Tour on the Continent, by J. E. Smith'
M.D. F.R.S. &c. page 200, Vol. I.

f On dividing 15,577, the height of perpetual froft at th<
equator, by the difference of the temperature ahove and below, il
is found that every 299 feet of elevation lefltn heat 1°, and on di-
viding 5,162 feet by 299, we have 17°, which fubtracted from
mean annual temperature of latitude 32°, give 52, for the Sen
bf Madeira, correfponding with the latitude 51° (1.)

X See Kirwan's table of mean annual temperatures.

ON THE NATURALIZATION OF PLANTS. ]55

In Fofter's account of Cook's fecond voyage, it is men- Instances of
tioned, that the trees on New Zealand were growing fo clofe ^^ fo^the'lea
to the edge of the water, that the fliip's mails were entangled where fheltered.
among their branches ; and in particular fituations the fame
proximity of trees to the fea might be obferved in various lati-
tudes. At Fairhead, the mod northerly extremity of Ireland,
and expofed to the fury of the northern ocean, the forbus
aucuparia {mountain afb), betula alba (birch), quercus robur
(oak), with other indigenous trees, grow luxuriantly within
15 or 20 yards of high-water-mark. The reafon of this ap-,
pears to be that they grow upon the lower part of very high
land, which caufes an eddy to be formed about them when
the wind blows from the fea ; and by the fame high land they
are protected from the fouth and fouthweft winds.

On the top of the rocks the wind rages with the greater} As plantations

fury, even the grafs feeming blighted, whereas below the j£"vf ne J5 *hc

rocks every plant appears in a thriving irate, and fome houfes ed, it is proper

fituated on the lower part never have their thatched roofs dif- .t0 1befih.t0 P1;"1*
, , , i n T i it n inland» in order

turbea by the ltorms. In every other part along the coaft that the firft

where land is of the fame form it is covered with thriving trees may pro-
wood, but where the land is nearly level for a length of way tjje coaft .
inland no wood appears, and every hedge is feen never to rife
higher than the top of the bank which protects it from the wind.
Therefore in order to plant near the fea on a low fhore, it is
neceffary to commence the plantations a confiderable way in-
land, and to allow the young trees to have others feveral feet
taller than themfelves behind them : thefe will have the fame
effect as high land, for by means of the oppofition offered by
innumerable Items and branches the force of the wind will be
greatly leffened ; as we may find by Handing on the windward
fide of a thick wood during a ftorm, where, if the trees are
lofty, the wind is much lefs violent than on an open4plain. In
water the effect of this kind of oppofition is vifible, for if into
the bed of a fwift itream we drive a number of flakes, the
water, although it continues to flow, yet has its velocity dimi-
nithed confiderably.

Our firft plantations in an expofed place ought always to and the firft
be of fuch trees as are natives of mountains for thefe are plantations
fitted by nature to bear the rude blafts of winter, and by the natives of moun-
ftiffnefs of their leaves, or flexibility of their footftalks, to re- tains

main

156 METHOD OF REMEDYING INCONVENIENCES

main uninjured by a dimmer ftorm. Of the firft, we have the
various race of pines ; of the laft, the birch, the afpen and
the mountain afli *.

Thos by a careful inspection of the operations of nature, is
the hand of man enabled to collect the productions of diftant
countries around his home, cover the arid heath with waving
green, and make the lonely wildernefs aflume a pleating
gloom.

II.

A Method of remedying certain Inconveniences arifing from the
Inequality of Heat in large Dijlillation. By Sir A. A. Edel-~

ERAUTZ f.

In diftillation IT is generally known that every diftillation confifts of two
thcoperationsare principal operations ; the conversion of the matter under dif-
and2. to con-' tillation into fteam by heat, and the condenfation of that fleam
denfe. by cold. In order to the fpeedy accomplifliment of thefe two

objects, and without any unneceflary expence of fuel, a per-
fect equilibrium muft be eftablithed between the evaporating
heat and the condenfing cold; that is to fay, fuppofing this-
laft to be conftant, as it may be practically made, (a given
quantity of water at a fixed temperature paffing through the
The heat muft cooler in a given time.) The heat mull then be fo regulated

be adjufted to ^^ the quantity of fteam produced (hall be neither more or
the cooling _ • J ' f .

power. lets than can be condenled in the lame time, by the cold ap-

plied to it. A want of attention to this circumftance produces
the two following inconveniences, particularly in the diftilla-
tion of fpirituous liquors.
Strong heat ]ft. jf tne fire De too brifk, a confiderable quantity of the

diffipates part of confined fteam will pafs from the worm into the open air, oc-
the vapor. cafioning a lofs of the matter under diftillation, and a wafte of

fuel.

* Among the rocks of A'gnew's Hill in the county of Antrim,
I found thepopulus tremula (afpen tree) growing luxuriantly on
the eaftern face, at about the elevation of 1,450. And on the top
of Slemifh, the forbus aucuparia (mountain a/h) expofed to every
ftorm at the elevation of 1 ,398 feet.

} Annales de Chimie, XLV. 297.

2nd.

FROM INEQUALITY OF HEAT IN LARGE DISTILLATION. ]57

2nd. If the fire be differed to flacken too much, theconden- Low heat caufes
fation produces a vacuum in the worm and the alembic, which ente°Ut^n*,r_t(>
not being fupplied in the fame proportion by frefh fleam, oc- when expelled
cations the outer air to enter, which renders the evaporation carries out va-
and condenfation more difficult, and when it is, at laft, driven
out, it takes with it a portion of the fleam, thus occafioning a
lofs of the matter under diftillation, as well as a lofs of time.

In order to remedy thefe defects, and at the fame time to Inftruments for
furnifh a fimple method of regiflering the adual heat, I have ^^ying thefc
thought of the following inflrument, which is applicable to
any diftilling apparatus, and is nothing more than an applica-
tion of known principles of theory to actual practice.

a, b, c, d, Fig. 1. is a bent tube of copper or glafs in fe- An inverted
parate pieces, with a bulb at b; the upper end of the tube a {Jph™ °f.con"

i . , , l r ~ , denfed fluid, and

may be attached to the worm by means or a lcrew. The length a mercurial gage

b c, c d is of four feet, and the capacity of the bulb b, is a little which a,,°w3 of
larger than the whole capacity of the tube be d. The diftillation internal or ex-
being begun, the condenfed fleam will pais by a and the bulb te.rnal preiTure,

b, into the tube bed; and when its two arms are full, the li- „,, ?" • con?'

' * ^ municdcion from

quor will run out at d, into the veftel J n tended to receive it. without.
Thefe two arms, therefore, remain full during the whole of
the diftillation, and in this confifts the remedy to the inconve-
nience above-mentioned ; it is evident that if the fire becomes
too quick, the uncondenfed fleam cannot force a paflageto the
outer air, in order to diffipate itfelf, till it has driven out all
the liquor contained in the tube b c, and has overcome the
preftlire of a column equal in height to c d. Again, the outer
air cannot enter to fill up the vacuum produced by the flow-
nefs of the fire, but by driving back the column dc, and
overcoming the prefture of the fame height. Now this co-
lumn being four feet, gives range and time fufficient for the
operator to regulate the fire accordingly. If the tube bed
were made of glafs, we fhould only have to obferve the level
of the liquor in the two arms, the fall in b c would indicate
that the heat Ihould be diminiflied, and in c d, that it (hould
be increafed: but tubes of this length being fubject to acci-
dents, I prefer attaching to c a fmall regulator of glafs, e f e,
the two arms of which, e f, each of three inches long, con-
tain mercury, and which rifing in them alternately, will indicate
the flate of the heat and ihe fleam with fufficient accuracy.
This regulator may be placed in a bottle or flafk, which will

protect

J58 ACCOUNT OF A TIME-PIECE,

protect it from injury. Between it and the worm is a cock gr
which at firft communicates with the outer air, but after hav-
ing produced a ftrong heat, the fleam is feen efcaping at g ;
by turning it a communication is opened between the worm
and the regulator, which then begins its operations. The bulb
b prevents the liquor prefled by the outer air from rifing into
e f e, and the alembic. It is fuperfluous to add, that, of
whatever form the capital may be, it fhould be well luted, in
order to prevent the accefs of the outer air.

III.

Account of a Time-Piece for regifiering the Attendance of Watch-
men, andforfimilar Purpqfes; conjlrudied by Mejfrs. Boulton
and Watt, for the Right Honourable ^cMarquis of Ex*
e t e R . In a Letter from h is Lord/hip .

To Mr. NICHOLSON.
SIR,

jTIAVING feen Mr. Day's account of his watchman's regu-
lator in your Journal, dated June], 1803, I think it may be
proper to inform you that a clock for a fimilar purpofe has been
invented by Meffrs. Boulton and Watt, Birmingham, which
cofts no more than thirty (hillings. I have had two of them
above four years. They go eight days, and have a face like
clock, but do not ftrike. The dial goes round, and the hour
finger is fixed ; round the edge of the dial are moveable iron
pins, correfponding with the quarters in each hour. A fmall
hammer placed behind the hour finger, when -moved down-
wards, puflies into the dial, one of the pins which happen to
be under it at the time, which pin remains fo abafed until the
dial nearly returns to the fame place, when by an inclofed
plane the pin is raifed up into its firft pofition. This gives
time to have the machine examined in the morning, to fee
how many pins have been ftruck, and at what time they were
pufhed downwards. The hammer is moved by the pulling of
a chain with a handle, like houfe-door bells, which, by cranks
and wires is attached to it. I have one in my library, the
handle is out of doors. The other machine is placed n a build-
ing

POISONOVS HONEV OF NORTH AMERICA. 159

ing at the other end of my premifes. I have always two
watchmen every night, and they go the round every half hour.
I am,
SIR,

Your obedient humble fervant,

EXETER,
Burghles, June 9, 1 8 03 .

IV.

Some Account of the Poifonous and Injurious Honey of North
America. By Benjamin Smith Barton, M. D.*

IN the year 1785, I had an opportunity of obferving fome Honey is fome-
of the difagreeable effe&s of our wild honey upon feveral per- *™™T°fJ™h *
fons who had eaten of it, in the weftern parts of Pennfylvania, injure the con-
near the river Ohio. From thefe effe&s I was perfuaded, that ftitutl0n-
a fubftance which is generally confidered as entirely innocent,
is capable of doing much injury to the conftitution. I was,
therefore, induced to pay fome attention to the fubjedt. The
refult of my inquiries I now communicate to the Philofophical
Society.

It is not neceffary to make any remarks on the fabric of ho- it always par-
ney. It may be fufficient to obferve, that the honey will al- takes of the n*~*
ways partake, in a greater or IefTer degree, of the fmell, the ers whence it
tafte, and general properties, of the flowers from which it is « gathered.
obtained. This obvious facTfhould have folicited more of the
attention of thofe whofe employment it is to raife large num-
bers of bees, for the purpofe of obtaining the valuable pro-
duct of thefe little infedts. But, in this country at leaft, hardly
any attention has been paid to the fubje<5t. Perhaps, the fol-
lowing loofe hints, by pointing out fome of the fources from
which an ill-flavoured or pernicious honey is obtained, may be
of fome fervice to the new or remote fettlers of our country.

I mull obferve, that in thefe hints I do not mean to include Common honey,
among the difagreeable confequences of the eating of honey,
the occafional effecl: of its purging : for although, as I fhall
prefently obferve, a purging is one of the common effects of
the poifonous honey, yet the moft innocent honey will often

* American Tranfa&ions, V. 51.

induce

160

roiaoNous honey op north amerIca.

Symptoms pro-
duced by dele-
terious honey*

induce the fame ftate of the body, when it is eaten in large
quantities, or when it meets with an irritable flate of the
bowels.

The honey which I call deleterious or poifonous honey, pro-
duces, as far as I have learned, the following fy mptoms, or
effects : viz. in the beginning, a dimnefs of light or vertigo,
fucceeded by .a delirium #, which isfomelimes mild and plea-
fant, and fometimes ferocious; ebriety, pain in the ftomach
and inteflines, convulfions, profufe perfpiration, foaming at
the mouth, vomiting, and purging ; and, in a few inflances,
death. In fome perfons, a vomiting is the firfl effect of the
poifon. When this is the cafe, it is probable, that the per-
fons fuffer much lefs from the honey than when no vomiting
is induced. Sometimes, the honey has been obferved to pro-
duce a temporary palfy of the limbs ; an effect which I have
remarked, in animals that have eaten of one of thofe very ve-
getables f from whole flowers the bees obtain a pernicious
honey.
Tbey arc feldom Death is very feldom the confequence of the eating of this
kind of honey j. The violent impreffion which it makes upon
the flomach and inteflines often induces an early vomiting or
purging, which are both favourable to the fpeedy recovery of
the fufferer. The fever which it excites is frequently relieved,
In a fliort time, by the profufe perfpiration, and perhaps by
the foaming at the mouth. I may add, that as the human
' conftitution refifts, to an aflonifhing degree, the effects of the
narcotick and other poifonous vegetables that are belt known
to us, fo we need not wonder, that it alfo refifts the effects
of the deleterious honey, which is procured from fuch vege-
tables.

fatal

* An intelligent friend of mine related to me the cafe of a perfon
who, for a thort time, was feverely afFecled from the eating of wild
honey, in Virginia. He imagined that a perfon feized him rudely
by one arm, and then by the other. After this, he fell into con-
vulfions, from which, however, he recovered, in about an hour.
It was imagined that this honey was obtained from a kind of poifon-
ous mufhroom.

f The Kalmia latifolia.

% We fliall afterwards fee, that not one of Xenophon's men died
from the deleterious honey which they had eaten, in large quantities,
on the mores of the Euxine-Sea.

It

POISONOUS HONEY OF NORTH AMERICA; \0\

It deferves to be mentioned, that the honey which is formed ReTpefting the
by two different hives of bees in the fame tree, or at a little UnwhSefome or
diftance from each other, often poflefles the moftoppofite pro* poifonous honey,
perties. Nay, the honey from the fame individual comb is
fometimes not lefs different in tafte,- in colour, and in its ef-
fects. Thus one uratum or portion of it may be eaten with-
out the lead inconvenience^ whilft that which is immediately
adjacent to it (hall oceafion the feveral effects which I have
juft enumerated.

I have taken fome pains to learn nhat are the figns by which
the deleterious honey may, at firfr. view, bediftinguifhed from
innocent honey. I am informed that there is no difficulty in
the matter.

The poifonous honey is faid, by fome; to be of a crimfon-
colour; by others, it is faid to be of a reddifh-brown colour,
and of a thicker confluence than common innocent honey.

Thefe are the figns by which, I am told, the moft experi-
enced hunters, in the fouthern parts of North-America, are
enabled to diftinguifh pernicious from innocent honey.

On a fubjecl fuch as this> I feel every difpofition to pay a
good deal of deference to the experience of an American
hunter. Even philofophers may obtain much ufefui informa-
tion from hunters, however wandering their life; however
rude their manners. It is in the povfrer of our hunters to en-
rich natural hiftory with many important fa£ts. But we ought
not, I pjrefume, to confide implicitly in every thing they
tell us.

I have good feafons for doubting whether the figns which I The external

have mentioned will enable us, in every inftanee, to deter- gns 3re n,°^

. J very condttfiyfc

mine whether honey be poilonous or innocent.

The honey of the bee, undoubtedly fometimes partakes
of the colour of the flowers from which it is gathered. The
bees gather honey from many flowers of a crimfon colour,
and from many flowers whofe colour is a reddifli brown. In
thefe cafes, it is probable that the honey will fometimes
borrow, in fome degree, the colour of the flowers. Yet
there are many crimfon-coloured and reddifh-brown coloured
flowers that are perfectly innocent. The honey obtained
from them will, I prefume, be innocent alfo. Mr. Bruce
fays he was furprifed to fee, at Dixan, in Abyffinia, •? theRedhoc«j|
feoney red like blood, and nothing," he remarks, " can have

Vol. V.-^July, M m

|£2 POISONOUS HONEY OF NORTH AMERICA.

an appearance more difgufting than this, when mixed with
melted butter *." Nothing is faid, by this author, that can
lead us to fuppofe that the Dixan honey was poifonous. From
the manner in which it is mentioned, it is pretty evident that
it was not poifonous. Linnaeus informs, us that in Sweden
the honey, in the autumn, is principally gathered from the
flowers of the erica, or heath, and that this honey is of a
fomewhat reddifh colour ; and accordingly, he obferves, thofe
provinces of the country that are deftitute of the heath, fuch
White honey. as the province of Oelandia, furnilh a white honey +. The
great naturalift fays nothing concerning the properties of the
heath-honey. However, we may prefume, when we re-
collect the minute accuracy of Linnaeus, that this honey did
not poflefs any dangerous properties, otherwife he would have
noted the circumftance. Whilft I reiided in Edinburgh, I
had the honey from the Highlands frequently brought to my
table. I often remarked that this honey had a dirty brownifh
colour, and I was told that it was chiefly procured from the
different fpecies of erica, perhaps principally from the " bloom-
ing hather}," which abound in the Highlands. I never
heard the people in Edinburgh, although they confume
large quantities of this honey, complain that it poflenes any
noxious property. If it were actively poifonous, or injurious,
the quality would have been, long fince, obferved. I welt
remember, however, that, for two years that I ufed it, it
almoft always rendered me drowfy. Sometimes, indeed, it
compofed me to fleep as effectually as a moderate dofe of
laudanum would have done. A foreigner, who had not been
accuftomed to eat anodyne honey, was better capable of re-
marking the effect which I have mentioned than the natives,
who have been in the habit of ufing it from their infancy.
I do not find that this fingular property of the Scots honey has
been noticed by any writer §. I have, therefore, related it,

* Travels to difcover the fource of the Nile. Vol. V. or Ap-
pendix, p. 151. Quarto edition.
•f- Fauna Suecica.
J Burns.

§ Dr. Withering fays bees extract a great deal of honey from the
flowers of the erica vulgaris, or common heath, and he remarks that
*' •« where heath abounds, the honey has a reddifh call." A botanical

arrangement of Britifh plants, &c. Vol. 1ft.

though

POISONOUS HONEY OF NORTH AMERICA. IQ$

though it rather oppofes any objection to the figns employed
by our hunters to diftinguifti poifonous from innocent honey.
But he who is ftudious of truth, fliould relate ufeful fa6h as
they are, without regarding what is their connection with a
favourite fyftem, or opinion.

The learned Jofeph Acofta fpeaks of a grey-coloured honey
comb which he faw in the province of Charcas, in South-
America. The honey of this comb, he fays, is «' fharp and
black." He fays nothing farther of its properties *.

An ingenious friend of mine f, to whom the public are in- The poifonou*
debted for a variety of valuable information concerning the ^^J™3^
natural productions of various parts of North-America, in- diftinguifhed but
forms me, that, in the Carolinas and Floridas, the poifonous b* cautioU3 *$j
honey is fo fimilar, in colour, tafte, and odour, to the com-
mon, or innocent honey, that the former cannot be diftinguifh-
ed from the latter. It is owing, he fays, to this circumftance,
that fo many accidents daily happen from the ufe of the wild
honey. He was informed, that it is experience alone which
enables the hunters and others to determine, whether the
honey which they find in the woods be poifonous or innocent.
They have obferved that the injurious effects manifeft them-
felves in a fhort time after the honey is taken into the ftomach.
They are accuftomed, therefore, to eat a fmall quantity, be-
fore they venture to fatisfy their appetite. Should this pro-
duce ant/ difagreeable effects, they do not think it prudent to
continue the ufe of it. But, if in a fhort time, it fliould oc-
cafion no inconvenience, they think they may, with perfect
fafety, indulge their appetite to the full.

I have been informed that the poifonous honey, by boiling Sa5cl tobe «»-
and by draining, may be rendered as innocent as any honey boJlinfaal *
whatever. It is, likewife, faid, that by long keeping it be- Graining,
comes harmlefs.

The honey of which I am treating is poifonous to dogs, as
well as to men.

Hitherto, I have not been able to obtain any certain in- Remedies,
formation concerning the means to be purGied in the treat-
ment of perfons labouring under the effects of the poifonous

* The Natur.aH an4 Morall Hiftorie of the Eaft and Weft
Indies, &c. p. 303. '
f Mr. William Bartram.

M 3. honey

\$± POISONOUS HONEY OF NORTH AMERICA!

honey. It is faid that the Indians, and fame of the Whiles,
ufe cold bathing with advantage. It is probable that this
practice has been ufeful. As the effects produced by this
honey are fo fimilar to thofe produced by feveral narcotic
vegetables that are well known to us, iuch as opium, hen-
bane *, thorn-apple +, &c. it is probable that the fame means
of treatment will be found ufeful in both cafes. Qf thofe
means it is not neceflary to make particular mention in this
place.
The bees them- ft would be curious to afcertain, whether the bees are
bably injured by ever mjlired or deftroyed by the quaffing of the nectar of the
jhe plants which flowers from which they prepare the poifonous honey. It is
Kone n0X1°US probable that they are ; and, perhaps, fome of the difeafes
of thefe little infects may arife from this fource t. It is true,
indeed, that there are fome poifonous plants the nectar of
which the bees will not touch. This is the cafe with the fri-
tillaria imperials, or crown imperial §. I do not remember
to have feen bees in, or immediately about, the flowers of
the common rofebay, or oleander j|, in the tube of which there
is a fluid which deft toys thoufands of the common houfe flies.
But what is called inftind is not always fure. The bees may
prepare an honey from plants that are very injurious to therm
The excellent Mr. Evelyn, fpeaking of the elm fays, " but
I hear an ill report of this tree for bees, that, furfeiting of the
blooming feeds, they are obnoxious to the lafk **, at their
firft going abroad in fpring, which endangers whole flocks, if
remedies be not timely exhibited ; therefore, 'tis faid, in great

* Hyofcyamus niger.

-J- Datura ftramonium.

X Dr. James E. Smith aflerts that the honey or ne&or of plants
is not poifonous to bees. Syllabus to a Cgurfe of Leftures on Botany ^
p. 23. I have fome good reafon to believe that, fometimes at leaft,
the contrary is the cafe.

§ Linnaeus, fpeaking of this plant, fays, " Nulla, excepto
Meliantbo, copiofiori melle fcatet planta, quam ha?c; fed apes id
non colliguntP Praelectiones in Ordines Naturales Plantarum.
EdidJt Gifeke. p. 297. Hamburgi, 1792.

|] Nerium oleander.

** This is one of the moll mortal difeafes of bees. It is beauti-
fully defcribed, and the remedies for it mentioned, by Virgil,
Georgic. lib. iv. 1. 251—280.

5 elm

POISONOUS HONEY OF NORTH AMERICA. 165

elm countries they do not thrive ; but the truth of which I am
yet to learn *".

In South-Carolina, in Georgia, and in the two Floridas, but Diftri&s where
more efpecially in Eaft-Florida, the inftances of injuries from ^f ^ J"^1*
the eating of wild-honey are more numerous than in any other
parts of North-America, that are known to us.

There is a tract of country included between the rivers
St. Ilia and St. Mary's in Eaft-Florida, that is remarkable for
abounding in vaft numbers of bees. Thefe infects, which
were originally introduced into Florida by the Spaniards f,
have encreafed into innumerable fwarms, from the facility
wilii which they procure their food, in perhaps the richeil
flowered-country of North-America. In this trad of country,
the alarming effects of wild-honey are often experienced, by
the fettlers, by wandring hunters, and by favages.

It j,s highly probable, that this poifonous honey is procured ^e^eratum#
from a confiderable number of the flowers of the countries flowers that
wluch I have mentioned. A complete lift of thefe flowers afford iU
would be acceptable : but fuch a lift it will be difficult to pro-
cure at prefent. Perhaps, my hints may induce fome intelli-
gent native of the country to favour us with his obfervations
on the fubject. Meanwhile, I am happy to have it in my
power to mention fome of the vegetables from whole flowers
the bees extract a deleterious honey, not only in the country
between the St. Ilia and St. Mary's, but alfo in fome other
parts of North-America,

Thefe vegetables are the kalmia anguftifolia and latifolia Enumeration of
of Linnaeus, the kalmia hirfuta of Walter j, the andromedu
mariana, and fome other fpecies of this genus.

I. Every American has heard of the poifonous properties Kalmia angus-
of the kalmia anguftifolia and latifolia, The former of thefe f0jia.
plants is known, in the United States, by the names of dwarf-
laurel, ivy, lambkill, &c. It has long been known, that
its leaves, when eaten by (beep, prove fatal to them. The
following fact will fliow that the flowers likewife are endued
with a poifonous property.

* Silva : or a Difcourfe on Foreft-trees, &c p. 133 and 134#
Dr. Hunter's edition.

f See Tranfaclions of the American Philofophical Society,
Vol. III. No. 31.

| Flora Carolinians, p. 138.

About

]66 .POISONOUS HONEY OF NORTH AMERICA.

Narrative of About twenty years fince, a party of young men, folicited

Jrorn^hofc vege- ^Y ^e Pr°fpe& of gain, moved, with a few hives of bees,
ubJes. from Pennfylvania into the Jerfeys. They were induced

to believe that the favannas of this latter country were very
favourable to the encreafe of their bees, and, consequently,
to the making of honey. They, accordingly, placed their
hives in the midft of thefe favannas, which were finely painted
with the flowers of the kalmia anguftifolia. The bees encreaf-
ed prodigioufly, and it was evident that the principal part of
the honey which they made was obtained from the flowers of
the plant which I have juft mentioned. I cannot learn that
there was any thing uncommon in the appearance of the
honey : but all the adventurers, who eat of it, became in-
toxicated to a great degree. From this experiment, they
"were fenfible that it would not be prudent to fell their honey ;
but, unwilling to lofe all their labour, they made the honey
into the drink well known by the name metheglin, fuppofing
that the intoxicating quality which had refided in the honey
would be loft in the metheglin. In this refpecl, however,
they were miftaken. The drink alfo intoxicated them, after
which they removed their hives.

In North-Carolina, this fpecies of kalmia and the andromeda
mariana are fuppofed to be the principal vegetables from
which the bees prepare the poifonous honey that is common
in that part of the United States.
The kalmia IJ. That the kalmia latifolia, known in the United States

uti aa po oiy ky tjie liames 0f laurel, great-laurel, wintergreen, fpoon-
haunch, fpoon-wood, &c. is alfo a poifon. Its leaves, in-
deed, are eaten, with impunity, by the deer"*, and by the
round-horned elk f. But they are poifonous to flieep, to
horned-cattle and to horfes. In the former of thefe animals,
they produce convulfions, foaming at the mputh, and death.
Many of General Bradock's horfes were deftroyed by eating
the leaves and the twigs of this fhrub, in the month of
June 1755, a few days before this unfortunate General's
defeat and death. In the fevere winter of the years 1790
and 1791, there appeared to be fuch unequivocal reafons for
believing that feveral perfons, in Philadelphia, had died in

* Cervus Virginianus of Gmelin.
f Cervus Wapiti, mihi.

confequence

POISONOUS HONEY OF NORTH AMERICA, \Q^

confequence of their eating our pheafant *, in whofe crops and infe&ing
the leaves and buds of the kalmia latifolia were found, that the,r flcftu
the mayor of the city thought it prudent and his duty, to
warn the people againft the ufe of this bird, by a public
proclamation. I know that by many perfons, efpeciaily by
fome lovers of pheafant-flefh, the circuraftance juft mentioned,
was fuppofed to be deftitute of foundation. But the founda-
tion was a folid one. This might be fliown by feveral well-
authenticated facls. It is lufficient for my prefent purpofe
to obferve, that the collection of a deleterious honey from the
flowers of this fpecies of kalmia gives fome countenance to
the opinion, that the flefh of pheafants that had eaten of the
leaves and buds of this plant may have been impregnated with
a pernicious quality +.

I have been informed, that our Indians fometimes inten- ufe<] for fu^e.
tionally poifoned themfelves with a deco&ion of the leaves
of this kalmia. The powder of the leaves has been employed
(but I fufpeft with little advantage) in the inflammatory itage
of certain fevers. From experiments made upon myfelf, I
find that this powder is ftemutatory.

To fome conftitutions the flowers of the kalmia latifolia,
«ven externally applied, are found to prove injurious.

III. The kalmia hirfuta appears to poflefs nearly the fame ^a|mja hirfuta
properties as the two fpecies which I have juft mentioned.

This pretty little flirub is a native of South-Carolina, Georgia,
and Florida.

In Georgia and in Florida, this fpecies of kalmia is fup-
pofed to be the principal vegetable from which the deleterious
honey in thofe parts of our continent is procured.

IV. The andromeda mariana, or broad leafed moorwort, Andromeda ma-
is a very common plant in many parts of North America, riana.

* Tetrao Cupido of Linnaeus.

+ It is not a new fufpicion, that the flefh of animals that have
eaten of the leaves, &c. of deleterious vegetables is fometimes
endued with a poifonous property. Georg, H. Welfchius, a very
learned German writer, quoted by Dr. Haller, (See Hiftoria Stir-
pium Indigenarum Helvetia Incboata. Tom. I. p. 433.) fays,
that the flefh of a hare which was fed with the leaves of the rho-
dodendron ferrugineum proved mortal to the guefts: This fpecies
of rhododendron is a native of Switzerland, Siberia, and other
parts of the old world.

Thfc

168 POISONOUI HONEY ©F NORTH AMERICA.

The leaves are poifonous to fheep. The petioli, or foot*
ftalks of the leaves and the feeds, within the feed-veffe!, are
covered with a brown powder, fimilar to that of kalmiae.
This powder applied to the noftrils occafions violent fneez-
ing *; From the flowers of this plant, the bees extract con-
fiderable quantities of honey ; and it delerves to be mentioned
that this honey, as well as that obtained from fome other
American fpecies of andromeda, has frequently the very (me\\
of the flowers from which it is obtained f.
Plant? affording I have already obferved, that it is highly probable, that
the American poifonous honey is procured from the flowers of
a confiderable number of the plants of the country. I have
mentioned but a few of them. But there are many others
which I have fome reafons for fufpecfing are alio capable of
affording an injurious honey. Indeed, every flower that is
poifonous to man, and is capable of affording honey, may
produce an honey injurious to man ; fince the properties of
this fluid are fo dependant upon the properties of the plants
from which it is procured. There is, therefore, more poetry
than philofophy in the following lines of Mr. Pope ;

*' In the nice bee, what fenfe fo fubtly true,

f* From pois'nous herbs extracts the healing clew."

Essay on Man, Epiftle L lines 211 & 212:

I have been informed that, in (he fouthern parts of our con-
tinent, there is a plant, called hemlock, from the flowers of

£ For fome information relative to the properties of the andro?
meda mariana, fee Collections for an Eflay towards a Materia
Medica of the United States, pages 19, 20, 47. Philadelphia,
1798.

-f- In juflice to the fine genus of andromeda, I muft obferve, that
all the (pecies do not furnifh a pernicious honey. The androrqeda
nitida or lucida of Bartram affords an abundance of ne£tar? or
honey. The flowers of this fpecies are called by the country
people cf Carolina and Georgia, " honey flowers, " not, however,
mcrtly from the circumftance juft mentioned, but f.-om the regular
pofition of the flowers on the peduncle, which open like the cells
cf a honey-comb, and from the odour of thefe flowers, which
greatly refembles that of honey. This fpecies grows abundantly
jn the fwanips called bay-galls. The inhabitants of Carolina are
univerfally of opinion, that it affords the greater! quantity of honey,
jind that of the beft quality.

whicft

POISONOUS HONEY OF NORTH AMERICA. ] fj9

which the bees prepare a honey that is poifonous. The Plants affording
flowers are faid to be yellow, and the root a deadly poifon. p° W10U* one'*
I do not know what plant this is. Mod probably, it is fome
Umbelliferous plant, perhaps a cicuta, an angelica, or a
fcandix.

Some fpecies of agaricus, at leaft fome fungous vegetables,
that grow in the fouthern itates, are extremely poifonous*
As accidents from the ufe of deleterious honey have happen-
ed in the fame countries in which thefe poifonous fungi grow,
it has bedn fuppofed, and aflerted, that the poifonous honey
H prepared from a dew that collects upon thefe fungi. Per-
haps, this fuppofition is not entirely devoid of foundation *.

I (hall now mention a few vegetables from the flowers of
which, I think, it will be found, that the bees colled a poifon-
ous, or injurious honey. Thefe are:

* If the celebrated author of the Recherches Philofophiques fur
Jes Americans be ftill living, this account of our poifonous and in-
jurious honey (thould my memoir fall into his hands) would afford
him fome entertainment. I would advife him to connect: the facts,
which I here communicate, with the remarks concerning our in-
fects contained in the firft volume of the Recherches (fee p. 169
■and 170.) I hope? however, that Mr. De Pauw, who, notwith-
ftanding his love of fyltem and his many errors, is certainly a man
of great reading, will recollect, that the Greek and Roman writers
(as we fhall afterwards fee) have faid much concerning the poifon-
ous honey of various parts of the old world. And now let me add,
that in America there is as good honey as in any other parts of the
world ; and there is not a fcarcity of this good honey. The honey
which is collected from the flowers of the tulip-tree (liriodendron
tulipifera), the buckwheat (polygonum fagopyrum), the red-maple
(acer rubrum), the clover (trifolium), and many other plants is '
excellent. The Abbe Clavigero fays, the bee of Yucatan and Chiapa
makes " the fine clear honey of Eftabentun, of an aromatic flavour,
fuperior to that of all the other kinds of honey with which we are
acquainted." (a) The Hiftory of Mexico, Vol. I. p. 68. Perhaps on
fome future occalion, I may communicate to the Philofophicai
Society a lift of thoie indigenous vegetables which, as furnifhing
an innocent and excellent honey, are worthy of prefervation in
the neighbourhood of apiaries. The lift is an extenfive one.

(a) This fine honey, according to the Mexican hiftorian, is
?• made from a fragrant white flower like jeflamine, which blows in
September."

I. The

170 POISONOUS HONEY OF NORTH AMERICA.

Plants affording 1. The rhododendron maximum, or Pennfylvania mountain
poifonous honey. JaureI# Thjs be|ongs to a very a6live genius of pIants< We

have already feen that one of the fpecies, the rhododendron
ferrugineum, was, long ago, obferved to produce the fame
effects which have been afcribed to the kalmia latifolia. An-
other fpecies, the rhododendron cryfanthum, has been found
a pqvverful medicine, and has been ufed in Ruflia, with
much advantage, in the ifchias, in chronick-rheumatifm, and
in other difeafes ; and we fhall immediately fee that from
another fpecies a poifonous honey has been procured in the
neighbourhood of the Euxine-Sea. The footftalks of the
leaves, and alfo the feeds, of our rhododendron maximum, are
covered with the fame brown powder as I obferved covered
the leaf-footftalks and the feeds of feveral of the andromedae,
and the kalmiae. This powder in the rhododendron, as well
as in the andromedae and kalmine, excites fneezing, and it is
curious to obferve that a fneezing is mentioned by Diofcorides
among the fymptoms produced by the honey about Heraclea
Pontica. That honey, as will be prefently fhown, is pro-
cured from the rhododendron ponticum.

II. The azalea nudiflora. This fine flirub is' well known
in Pennfylvania, and other parts of the United States, by the
name of wild honeyfuckle. Of its properties I know nothing
certain. It has, however, too much of the family face, and
is too frequently found in company with the rhododendron
maximum, and the kalmiae, not to make me fufpicious that it
partakes alfo of the characters of thefe deleterious vegetables.
Moreover, a fpecies of this genus, the azalea pontica of
Linnaeus, is fuppofed to be the aegolethron of Pliny, who
mentions it as the plant from which the poifonous honey about
Heraclea Pontica is prepared. The tube of the flower of our
azalea is perforated by the large bee, called bumble-bee.

III. Datura firamonium. This plant is known by a variety
of names, fuch as Jameftown-weed, gymfin; ftink-weed,
French-chefnut. Its active and poifonous properties are now
pretty generally known. Children have often been injured
by eating the feeds. The tube of the flower contains a con-
iiderable quantity of honey. This honey is bitter, and has
much of the poifonous fmell. Bees quaff it. But admitting
that it is of a poifonous nature, it does not follow that our
cultivated bees (if I may be allowed to ufe this expreftion)

will

POISONOUS HONEY ©F NORTH AMERICA. J7[

will collect fo much of this honey as to prove injurious to thofe

who eat of it. But, in particular places, where this plant has

been permitted to increafe to a great degree, large quantities

of honey may be collected from it : and I cannot help fuf-

pecling that the ufe of this honey may prove injurious *.

Some of the ancient writers of Greece and Rome have re- Ancient ac-

lated innances of the deleterious properties of the honey oicounts °f

_, , ,:. *. ;: r * ■ I- i noxious honer.

certain countries. the botanift Diofcorides, ipeaking ot the

rhododendron ponticum, a fpecies of the fame genus to which
our mountain laurel belongs, has the following words,:
" About Heraclea Poniica, at certain feafons of the year,
the honey occafions madnefs in thofe who eat of it j and this
is undoubtedly owing to the quality of the flowers from which
the honey is diitilled. This honey occafions an abundant
fweating, but the patients are eafed by giving them rue, falt-
meats, and metheglin, in proportion as they vomit. This
honey," continues the Greek botanift, " is very acid, and
caufes freezing. It takes away rednefs from the face, when
pounded with coftus. Mixed with fait or aloes, it difperfes
the black fpots which remain after bruifes. If dogs or fvvine
{"wallow the excrements of perfons who have eaten of this
honey, they fall into the fame accidents f.

Pliny has alfo taken notice of this poifonous honey. " In
fome years," fays the Roman naturalift, ?' the honey is very
dangerous about Heraclea Pontica. It is known to authors
from what flowers the bees extract this honey. Here is what
we have learned of the matter. In thofe parts, there is a
plant called a:golethron, whofe flowers, in a wet fpring, ac-
quire a very dangerous quality, when they fade. The honey
which the bees make of them is more liquid than ufual, more
heavy, and redder. Its fmell caufes fneezing. Thofe who
have eaten of it fweat exceflively, lie upon the ground, and
call for nothing but cool drinks $". He then makes the very
remarks which I have quoted from Diofcorides, whofe words,
indeed, as Mr. Tournefort obferves, he feems to have merely
tranflated. The following remark, however, appears to be-

* See the late Dr. Samuel Cooper's inaugural differtation on the
properties and effects of the Datura Stramonium, p. 33. Phi-
ladelphia, 1797.

f Diofcorides, as quoted by Mr. Tournefort.

I C. Plinii Secundi Natmalis Hiftorise, Lib. XXI. cap. xiii.

long

noxious honey.

J72 POISONOUS HONEY OF NORTH AMERICA.

Ancient ac- long to Pliny : " Upon the fame coaft: of the Pontus, there
is found another fort of honey, which is called mcenomenon *,
becaufe thofe who eat of it are rendered mad. It is fuppofed,
that bees colled it from the flowers of the rhododendros, which
is common among the forefts. The people of thofe parts, al-
though they pay the Romans a part of their tribute in wax,
are very cautious how they offer them their honey f ."

The Greeks and the Romans have often defcribed the
various plants that were known to them, in fuch dark and
obfeure terms, that the botanifts of modern times are frequent-
ly at a lofs to determine, not merely the fpecies but alfo the
genus the ancient writers have mentioned. With refpeft,
however, to the plants which I have juft mentioned, the
difficulty does not feem to be great. Mr. Tournefort has, I
think, fnown, in a very fatisfaclory manner, that the aegole-
tbron of Pliny in the chamee-rhododendros pontica maxima,
Mefpili folio, flore luteo of his ]nftitutiones, a plant fince
defcribed by Linnseus, and by other botanifts, by the name of
azalea pontica. Mr. Tournefort has likewife fhown, that the
other plant called by Pliny rhododendros in his chamierhodo-
dendros pontica maxima, folio laurocerati, flore coeruleo
purpurefcente j. This is the rhododendron ponticum of
Linnaeus. It is confiderably allied to the azalea pontica.

Xenophon has recorded the remarkable effects of fome
poifonous honey, in his celebrated work, called Memora-
bilia.

When the army of the ten thoufand had arrived near Tre-
bifond, on the coaft of the Euxine or Black Sea, an accident
befel the troops which was the caufe of great conffernation.
*' As there were a great many bee-hives," fay the illuftrious
general and hiftorian, " the foldiers did not fpare the honey.
They were taken with a vomiting and purging, attended with
a delirium, fo that the lead affecled feemed like men drunk,
and others like mad men, or people on the point of death.
The earth was ftrewed with, bodies, as after a battle; not a
perfon, however, died, and the diforder ceafed the next day,
about the fame hour- that it began. On the third and fourth

* From the Greek verb, Ma.'vQ^j&j, infanio.

f Ibid.

X Inftitutiojies, &c,

days,

POISONOUS HONEY OF NORTH AMERICA. J73

days, the foldiers rofe, but in a condition people are in after Ancient ac-

tati'ng a ftrong potion V count* ofk

„. r . . . noxious honey.

The fame fad is recorded by Diodorus Siculus.

Mr. Tournefort thinks there is every probability that this

poifonous honey was fucked from the flowers of fome fpecies

of chamaerhododendros, or rhododendron. He obferves that

all the country about Trebifond is full of the (pedes of this

plant, and he remarks that Father Lambert, Theatin mif-

fionary, agrees thut the honey which the bees extract from a

certain fhrub in Colchis or Mingrelia, is dangerous, and

caufes vomiting. Lambert calls this fhrub oleandro giallo, or

the yellow rofe-laurel, which Mr. Tournefort fays is, without

difpute, his chamaerhododendron pontica maxima, Mefpili

folio, flore luteo f ; the azalea pontica, already mentioned.

There are feveral pafiages in the Roman poets, which plainly

(how, that they were no ftrangers to the poifonous properties

of certain kinds of honey. It is not neceflary to mention all

thefe paffages. But the following are worthy of notice.

Virgil cautions us not to fufFer a yew tree to grow about

bee-hives :

Neu propius te&is taxumfme.

Georgic Lib. IV. 1. 47.

In his 9th Ecologue, the fame philofophic poet fpeaks of
the yews of Corfica as being particularly injurious to bees.
Sic tua Cynuvas fugiant examina taxos. 1. 30.

The honey of Corfica, as Dr. Martyn ftrongly exprefTes
it, " infamous for its evil qualities *."

The

* Thefe are nearly the words of Mr. Totirneforfs tranflation.
I am forry that I have not the original work of Xenophon at hand.

t See Tourneforfs Voyage into the Levant. Vol. iii. p. 68.
Englifli tranflation. London, 1741.

X $ee his Tranflation of the Georgics of Virgil, note to line 47,
in book IV. Dr. Martyn's criticifms and annotations always de-
mand attention. I greatly doubt, however, if the taxus of Virgi!
be the common yew, or any fpecies of that genus. Martyn hirnlelf
allows, that " it does not appear from other writers (befide Virgil),
that Corfica abounded in yews." I have been affured, that the yew
is not an indigenous vegetable in that ifland, and that it is even
rare among the foreign vegetables. It may, indeed, be faid,
perhaps it was common in the time of Virgil. I wouldobferve,
that the ye\v is mvich lefs poifonous than has been commonly fup-

pofti

2 Y4" POISONOUS HONEY OF NORTH AMERICA.

Advantages of The raiting of bees, for the purpofes of procuring their

SoTtoVhepSmci nonev anc* tne*r wax» mav> at *°me future period, become an
•ear beehives, objeft of great importance to the United States. Surely then,
*c# it would be a matter of confequence to attend to the cultivation

or prefervation of thofe vegetables which furnifti an innocent
and a well-flavoured honey, and a good wax. But even in a
more limited view of the fubjeel, fome knowledge of thefe
vegetables feems to be indifpenfibly neceflary . And in the new
fettlement, whither the fettler has carried his bees, where im-
provements are ftill very imperfect, it cannot be deemed a tri-
vial talk to have pointed out fome of thofe vegetables from
which an injurious honey is obtained.

The ancients, who, in fome refpe&s at leaft, were equal
to the moderns, appear to have paid much attention to this
fubject. Virgil * and Columella have both told us what plants
ought to grow about apiaries. It is unneceflary to repeat, in
this place, what the two Roman writers have faid on the
fubject. The Georgics of the Mantuan poet are in the hands
of every man of tafte ; and the work of Columella fjhould
be read, wherever agriculture engages the attention of gentle-
men.

The proper management of bees may be confidered as a
fcience. It is not fufficient that bees merely make honey and
wax. Their honey may be injurious or poifonous, and their
wax may be nearly ufelefs. To afiift, and to direct the labours
of thefe little infecls, the knowledge and the hand of man are

pofed. I know not that any modern writer has pretended that the
bees procure a pernicious honey from its flowers. Thefe facls give
rife to my fufpicion, that the taxus of Virgil was not the yew, or
taxus of the modern hotanifts. If not the yew, what vegetable was
it ? Perhaps, the buxus virens, or box. This vegetable abounds
in Corfica, where to this day it is known by the name of taxo* The
gentleman from whom I received this information allured me, that
the bees of Corfica are very fond of the flowers of the box, and
that the honey from this fource is reputed poifonous. The box is,
unqueftionably, a poifonous vegetable. But there is ftill a dif-
ficulty in the cafe. Virgil mentions both taxus and buxus. I
think there can be no doubt that his buxus (fee Georgic, lib. II.
1. 449.) is the buxus of the modern hotanifts.

* See Georgicorum, lib. IV. 1. 30.— 32.

f De Re Ruttica, libri XII.

required.

Q,N THE COMPOSITION AND USE OF CHOCOLATE. J75

required. Let, then, this interefted being be at lead attentive
to his own benefits and pleafures. Let hitn carefully remove
from about the habitations of his bees every fetid or poifonous
vegetable, however comely its colour or its form. In particu-
lar, let him be careful to remove thofe vegetables which are
noxious to himfelf. In place of thefe, let him fpread the
" marjoram and thyme/' and other plants, M the love of
bees*/' and his labours will be rewarded. He may, then,
furnifh his table with an honey not inferior to that of Mount
Hermettus, or of Athens; nor to that of Sicily, to which
Virgil has fo handfomely alluded in the feventh Eclogue :

Nerine Galatea, thymo mihi dulcior Hybla,
Candidior cygnis, hcderd formofior alb&.

L. 37, 38.

V.

On the Compofition and Ufe of Chocolate^ By Citizen Par-

MENTIER f.

^•MONG the fubftances with which the conqueft of the new Preparation of
continent has enriched the old, muft be placed the cocoa or chocolate ty the
cacao nut. From this fruit, or rather from this feed, it is that
the Mexicans have, from time immemorial, prepared their fa-
vourite beverage, chocolate: This confifts of cocoa roafted
and bruifed, which they mixed by ftirring water, and added
the flour of maize to give it confiftency, together with pi-
mento to flavour it. The exigence of fugar was unknown to Importation of
them, becaufe the cane, which is indigenous to India beyond .tne fugar cane
the Ganges, was not brought to Saint Domingo by Defticaca in(ncs ^^
until 1506; and becaufe Balaftro was the firft who fubmitted America,
this plant to the operation of the mill, in America £.

The Spaniards partook of the enthufiafm of the Mexicans in The preparation
the wonderful properties which they afcribed to chocolate ; £J^§e*i*
and its preparation, notwithstanding the little fkill it requires, Spaniards,
foon became in their hands an object of fpeculation ; they kept

* Armftrong.

f From the Annales de Chimie, No. 134, torn. XLV, 139.
X See an excellent fketch of the only hiftory of Sugar, by Dr.
Falconer, in our Journal, quarto feries, II, 136.

4 • it

176

Sugar added to

Difeovered by
•thcr nations.

Extraordinary
•virtues attribu-
ted to it.

Whether well
founded.

017 THE COMPOSITION AftD t'SE OF C&OCOlATtf.

Jt fecret, and fold, and continue to fell to other nations, a fim-1
pie parte of cocoa roafred, bruifed and brought into the form
of cylindrical rolls, for chocolate. *

The ufe of fugar having been rendered more common irf
Europe by the introduction of the cane into our colonies, it
foon became the u'niverfal condiment, and the Spaniards did
not fail to make it an addition to the preparation of chocolate,
for the purpofe of correcting its unp'leafantnek to thofe who
were tfnacctfftomed to this beverage ; but it was not till fome
time afterwards that other nations made the difeovery that co-
coa was its bafe, fugar its feafoning, and cinnamon and vanilla
its aromatic ingredients. This difcovery became a fource of
wealth to a number of individuals, who in their turn made a
myftery of it; hence arofe the chocolates of Italy, of Portugal,
and of Spain, which, compared with thofe prepared in Paris,
and the other towns of France, poflefs no fuperiority. Why
fhould we allow thofe countries to have fuch an advantage over
us? The ingredients which form chocolate are not cultivated
in them any more than with us, we all obtain them from the
fame fources and at the fame charges. At Naples, Lifbon,
and Madrid, the chocolate of France is in great efteem ; bat
it is an eftablifhed maxim in all countries that one (hall be
thought a prophet at home,- and this proverb may alfo be ap-
plied to chocolate.

I ftiall not enquire whether chocolate really deferves the en-
comiums beftowed on it, or whether it be advantageous in all
the cafes in which its ufe is recommended. If we credit the
writings of the phyiicians of the two worlds, nature has formed
the cocoa as a remedy for all the evils that afflict the human
race, and as the means of prolonging life beyond its accuftom-
ed limits. But it is difficult to guard againft exaggeration,
particularly on the fubject of productions which frequently have
no other value but that arifmg from their growing at a diftance
from us, and under another hemifphere. From experience
and obfervation we have learned nothing more than that cho-
colate is an agreeable aliment, light and of eafy digeition; it
is for that reafon given particularly to convalefcents, to per-»
fons of delicate habits, and to the aged. In fact, to obtain its
good effects uniformly, it is neceflary that the ingredients of
which it is compofed mould be properly felecled, well pre-
pared, and intimately mixed, fo as to form a foft, homogene-
ous, parte.

Oil

ON THE COMPOSITION AND USE OF CHOCOLATE. 17?

On the other hand, on confidering the nature of the fub- It »« « pharma-
ftances which form chocolate, and the mode in which their t-0
combination is produced, we are forced to acknowledge all
the characleriftics of a preparation truly pharmaceutical, and
to allow that it requires a degree of care and attention, of
which ordinary labourers are incapable without fuperintend-
ance and direction.

The felection of cocoa is not fufficient to give that quality to an<* requires t»
chocolate which it ought to have: this fruit muft be lifted, then mj^f ,. *
roafted by a gentle heat to deprive it of its humidity and to
develope the odour and flavour which belongs to it; it muft
be peeled grain by grain to feparate the bark, the germ or ra-
dicle and thofe nuts which appear to be fpoiled ; the cocoa,
thus picked, muft be ground for a long time with a certain
quantity of the fugar on a ftone, gradually heated on a fand*
bath ; the remainder of the fugar is not to be added until the
fecond bruiting, and the aromatic ingredients, which are
pounded with the fugar, are not to be put in till near the clofe
of t[ie operation. It is then divided into a mafs of a fuitable
weight, and faftiioned in tin moulds, whence it is taken when
cold to be wrapped up, care being taken to keep it in a dry
cold place : the winter is the mod favourable feafon for this
operation.

Since the various fpecies of cocoa which are found in com- Preparation of
merce could not, were each treated feparately, produce cho- chocolate for
colate of a good quality ; it is ufual to mix them in proportions pUrp0fes.
which are determined by theprice intended to be charged, and
by thetafte or fancy of the confumer; when it is flavoured by
cinnamon alone, it is called chocolat defantS : it bears the name
of chocolate of half, one, two, or three vanilloes, when there
are a half, one, two, or three pods of that fruit in a pound of
it, becaufe the weight of the pods are unequal.

Chocolate thus compofed is infinitely preferable to the crude Superior to that
pafte of cocoa which is ftill prepared in the Antilles, and which ^^fromtl,c
the Spaniards continue to fend to us, under the pretence that
it is more commodious in that ftate, becaufe the fugar and aro-
matic ingredient may be added in the reqtiifite proportion when
ufed, but the chocolate thus made does not pofTefs a perfect
homogenity. The butter of cocoa conftantly rifes to the fur-
face ; for when the fugar is bruited with cocoa in the ftone>
during the mixture, a more intimate combination of all the
Vol. V, — July. m N principles

Frauds in the
manufacture.

17S on the Composition and use of chocolate*

principles is effected. In a word, the chocolate thus obtained
is more completely dilTolved, more mifcible in water and con-
fequently more eafy of digeftion : on the other hand, although
cocoa does not become rancid fo eafily as the fruits which are
analogous to it, it may be apprehended that from being expofed
too fuddenly to the action of the heat neceffary to bruife the nut,
the oil and the batter which it contains being fet free, it may
* lofe part of its mildnefs and become acrid and heating*

Of the Frauds committed in the Fabrication of Chocolate.
It h, no doubt, unfortunate, that in the commerce of food,
in which the love of humanity, that fen lira en t fo pure and fo
natural, might feem to banith all want of confidence, and
every fordid intereft, we neverthelefs difcover that frauds are
multiplied in proportion as the objects pafs into different hands
to acquire their alimentary or medicinal properties. It is not
my intention to attach perfonal blame to any individual, but
the improper conduct of fome manufacturers render it necef-
fary to give precautions, which are, no doubt, ufelefs with re-
gard to others, who fulfil the duties of their ufeful profeffion
with a degree of fidelity worthy of the belt of times.

Baume, in his Elements of Pharmacy, and Demachy, in his
Art of the Liqueur-maker, have difcovered part of the abufes
which are committed in the fale of chocolate. I (hall feel
happy if, by adding fome observations to what has been al-
ready publilhed by thofe chemifts, I mould fucceed in preferv-
ihg the juft reputation it deferves, and which it has loft in the
Opinion of fome individuals only by the faults of the prepara-
tion, or by the addition of materials foreign to its compofition.
Inftance of the Among the number of perfons I have heard complain againft
bad efteftsaii- cnocoiate J fim\l inftance a lady of a tolerably good confti til-
ling from foreign . r-i •
ingredients. "On, to whom it had been prefenbedas a medicine; the ill ef-
fects (lie experienced from it gave me rcafon to fufpect the pu-
rity of her chocolate : I examined it, and found that it con-
tained a quantity of farinaceous matter. Now this fubftance
had been exprefsly forbidden by her phyfician ; I perfuaded
her not to difcontinue the ufe of chocolate, but to procure it
elfewhere: the uneafinefs, the oppreffion, and the acidity
which had tormented her, foon diiappeared, and her ftomach
Was infenfibly reftored. Thus the mean to which fhe ought
to have been indebted lor her cure, were likely to have proved
the caufe of her deftruction.

I thought

Partly noticed
by others.

ON THE COMPOSITION AND USE &§ CHOCOLATE. 1/i)

I thought it a duty to take this opportunity to examine other Examination of
chocolates bought indifcriminately from feveral makers; fome vanous kmds*
I found to be faithfully prepared ; but others contained the fa-
rina of wheat, others the farina of lentils, of peas and of beans,
and laftly, the fecula of potatoes. It will be faid that thefe
lubftances are not injurious to the animal economy; and to that
I agree. But in circumftances in which chocolate makes part The added »n-
of a regimen, and is prefcribedas a medicinal food, they can^ gredients though

!• ..... , . i , f r- i i • x i not unwhole-

not but be prejudicial to the health: betides, why introduce fomemaybeim.

them into it? they are intirely foreign to the compofition of proper in the
chocolate. Thefe obfervations apply to all the additions which
are mentioned in advertifements, and fuppofed by fome per*
fons to be improvements.

But admitting what is not true, that it is neceflary to make Any addition
chocolate thicker and more fubftantial, the mixtures here men- lmProPer>
tioned pught not to be made till the moment of its preparation,
and, if I may be allowed the exprefiion, under the eye of the
confumer. I muft obferve that, if it be thought ufeful to add
farinaceous matters, they mould always be employed in the
itate of fecula or ftarch, becaufe in that date they are deprived
of glutinous and extractive matter, and contain the alimentary
principle only.

The compofition of chocolate ought to be diftinguifhed from unlefs made by
its preparation, or making up ; the latter is in the province of tlie confumer.
the confumer, who may add at his pleafure the yolks of eggs,
for the purpofe of giving to his beverage a more faponaceous
character, and make life of milk inflead of water to increafe
its nutritive properties. It has even been remarked that many
who are unable to take milk without the immediate production
of acidity, have fucceeded in digefting it by the help of a little
chocolate ; but I again repeat, that if it fhould be the defign
Of a phyfician to prefcribe it, it is a medicine on whofe effects
he cannot rely, while its compofition continues arbitrary and
uncertain.

There are other frauds ftill more injurious to the effects of Injurious frauds.
chocolate, which I have alfo difcovered in my examination ;
fome makers procure, at a low price, the refufe of cocoa pafte,
from which the butter has been extracted, and replace it by
oils or animal fats ; others add roafted almonds, gum tragacanth,
or gum arabic ; and laftly there are fome who provide them-
felves with acrid, bitter, and newly gathered cocoa-nuts, be-

N 2 caufo*

130 ON THE COMPOSITION AND USE OF CHOCOLATE.

caufe thefe articles, which are always to be had at low prices
are capable of bearing a greater quantity of fugar, which pro-
portionally diminilhes (he prime coft of the chocolate.
Bad qualities We muft alfo obferve that, with the bell intentions, the cho-

want'of IkiH colate may be of inferior quality, without containing any fo-
reign ingredient, becaufe the fubftances in its compoiition may
have been ill-felefted, or the firfl operation may have been, in
fome refpecls, carelefsly prepared : the whole art confifts in
choofing the quality of the cocoa, and above all, in avoiding
either extreme in roafiing it ; if it be too flightly roafted, it re-
tains a difagreeable tafte ; if it be burned, it not only acquires
bitternefs, but the liquid prepared from it is black and wants
that uncluofity which is fo much admired in it ; and laftly, if
the germ be not feparated from the two lobes of the fruit, its
hard and horny ftale, refilling the action of the bruiting and the
boiling, it will be found entire at the bottom of the cup of
chocolate : its prefence is fufneient to (how that the firfl work,
which confifts in peeling the cocoa grain by grain, has been
neglecled, and that no more care has been beftowed on the
fubfequent operations.
or by carelefihefs Another obfervation is that the greater number of the work-
in the fabrica- men to wnom the fabrication of chocolate is confined require
much overlooking on the part of the mailer; they may be un-
faithful when they are employed by talk-work ; they will bruife
and work the pafte carelefsly, and, to lave labour and time,
they give a degree of heat which is too powerful and particu-
larly injurious to the quality of the chocolate.

Methods of difcovering the Frauds,
Methods of dif- It is not enough to have pointed out the frauds praclifed in
covering frauds. tjie fabrication of chocolate, and all the defects of negligence
or choice in the qualities of the materials and in the prepara-
tion. We (hall have only accompliftied half our object, if we
do not enable the con ( timer to diftinguifh them fo as not to be
miftaken.
Qualities of cho Thofe who are accuftomed to pure chocolate can eafily
colatewhen ge- ju^ge of its goodnefs : its fracture ought to (how nothing of a
granulated appearance. On tafting it, it ought to melt in the
mouth, and leave a fort of frefhnefs ; and laftly, in making
drink of it, it ought to acquire, either with water or with milk,
only a moderate confiftence.

2 In

ON THE COMPOSITION AND USE OP CHOCOLATE. , 18J

In all cafes when the chocolate leaves a pafty tafte in the
mouth ; when in preparing it, the liquor exhales on the firft
boiling a fmell of glue ; and when after its entire cooling it is
converted into a fpecies of jelly, we may be certain that the
chocolate contains farinaceous matter, in quantity proportioned
to the degree of the effecls here pointed out: if it depofits at
the bottom of the cup, fraall hard bodies, and an earthy or
gravelly fediment, it is a proof that it has not been well picked
and that raw fugar, more or lefs coarfe, has been ufed inftead
of refined fugar. The fmell of cheefe difcovers the prefence
of animal fats, and rancidity, or that of emultive feeds ; and
the bitter, faline or mufty flavour announces that the cocoa
employed was too green, too much roafted or decayed.

It cannot be too often repeated that chocolate is not an in- Probity and care
different preparation ; it does not require fcience, but probity preparation*.
and care; the makers of chocolate ought to leave the con-
fumers the right to add what they pleafe, when they are de-
firous either to increafe its efficacy or its pieafantnefs, accord-
ing to their own choice. They are often led by improper con-
fidence, or an economy ill underftood, to take it of an inferior
quality ; for chocolate in fad poflfefles a real value, notwith-
standing which, many are unwilling to pay more than half its
fair price, while others pay much too dear for it.

The limits of a notice will not permit us to point out the
characters which diftiuguifh the cocoas of commerce from each
other, nor to afcertain here at what price the chocolate can be
obtained by thofe who fabricate it : thefe details fiiall be the
fubjecYof a feparate memoir.

It refults from what I have faid, that chocolate is not at pre- General refult.
fent what it was when the Spaniards conquered Mexico, at
the beginning of the iixteenth century ; that no peculiar me-
thod U required for its preparation ; that though the proportions
of the elements which compofe it may be varied, the procefs
for applying and difpofing them to form a good compound,
muft be conftantand invariable; that its quality depends upon
the choice of the ingredients and the care employed in combi-
ning them ; that negligence, avarice, and quackery change its
nature fo much as to convert it into a heavy, indigeftible and
heating fluid ; that in order to procure it with all the qualities
which characlerife good chocolate, it is neceflary to buy of
dealers of good character, and at a fair price ; and laftly, that

every

182

ON THE COMPOSITION AND USE OP CHOCOLATE.

Additional ob
fervations by
Vadct.

Un-manufac-
tured chocolate
was found to
contain a metal
lie precipitate

every manufacturer who admits into the composition of choco*
late, materials which ought not to form a part of it, or at leaft,
which the confumer does not require, directly injures his health.
He who adulterates an article of general ufe, ought to be-
aware that though he conceals himfelf in the obfeurity of his
work-fhops to introduce low priced ingredients into his choco-
late, and to difguife them, yet he cannot efcape from a chemi-
cal analyfis, which can inftantly difcover his frauds, and de-
nounces his pernicious art and his name to the public notice.

To the observations contained in this notice, I (hall add thofe
which citizen L. C. Cadet has communicated to me on the che-
mical analyfis of certain foods. I (hall ufe his own words :
" The prefect of the police lately charged me to analyfe
fome chocolate which he fufpecled to contain fome noxious
fubftances. J fliall not enter into the detail of the multiplied
experiments which this examination required, but (ball confine
this notice to a (ingle remark, founded on the following fac"t :

" To difcover whether this chocolate contained any metallic
fubftance, I incinerated it and waflied the afhes with very pure
• nitric acid, which retained every thing that was fqluhle.

The filtered lixivium was clear, but I had fcarcely poured in-
to it a hidro-fulphuret, when I obtained a very abundant, black,
metallic precipitate. This refult gave me much uneafinefs,
becaufe J was ftill ignorant of the nature of the metal, and it is
always diftreffing to find a pernicious fubftance in an article of
food. I tried the lixivium with prufiiate of potam. Immedi-
ately a beautiful Pruflian blue was formed, which removed my
apprehenfions. I continued the examination with different
re-agents, and the oxalic acid (bowed me the prefence of lime.
It was interefting to learn whether the iron and the lime which
I had difcovered would be met with in all chocolates : I then
made an analyfis of the Caracca cocoa and of fome of the bed
from the plantations : I did not find in them either lime or

found in the nut metal. J immediately caufed fome chocolate to be prepared
but are mtrodu- . < i r

cedbythepre- from the lame cocoa and very white cryftallized fugar ; the
fent methods of analyfis difcovered a pretty large proportion of iron and lime.
It is, therefore, the fabrication which introduces thefe two
fubftances into the chocolate, and the quantity is greater in
proportion to the care bellowed on the manipulation. In facl
the cocoa is roafted in a cylinder of fheet iron fimilar to thofe
ufed in roafting>coffee. Jt is afterwards beat in an iron mortar

and

— of iron,

dad alfo lime,

»hkh are not

■Working.

ON THE COMPOSITION AND USE OF CHOCOLATE. ] g<$

and finally ground with an iron roller on a calcareous (lone,
the furface of which is worn by the friction, and affords the
lime.

" If the cocoa was roafted in a vefTel of lefs oxidable me- Propofed alter •
tal, or in well baked earthen-ware ; if the parte was ground atl0ns'
on a granite or a porphyry with a roller of the fame materials,
the chocolate would contain neither lime nor iron. In mani-
pulations on a large fcale, metallic fubftances are often intro-
duced into the fubjects of operation. Hence the extract of
tamarinds, and more particularly the extract of liquorice (Spa-
nish juice,) contains fo great a quantity of copper, that this
metal is frequently vifible at the firft infpeclion; for the fame
reafon apothecaries are obliged to purify them to avoid thofe
ferious accidents they might occafion.

" I was curious to know what was the proportion of metal proportions of
and earth thus introduced into the chocolate. I repeated the Sauced?6
experiments with care on quantities accurately weighed, and
I afcertained that five hectogrammes (one pound) contained
twenty-four decigrammes (forty-eight grains) of lime, and
twenty decigrammes (thirty-fix grains) of iron J this propor-
tion is th« minimum. Thus a map who takes a cup of choco-
late daily, at the end of the year has eaten eight hundred and
fixty-four decigrammes (three ounces) of lime, and feven
hundred and forty decigrammes (two ounces two gros) of iron,.

" As iron is a falubrious metal and as the proportion of the
lime in the chocolate is not very confiderable, no uneafinefs
need be formed refpecting the ufe of this aliment ; neverthelefs, Utility of analy*
I am of opinion that pliyficians will perceive the utility of col- fing allments«
lecting the analyfes of the different fubftances ufed for the
nouriftiment of mankind. Until our perfect growth, the deve-
lopement and folidification of our bones requires that we fhould
abforb from our food a certain quantity of lime ; and we re-
collect with intereii the labours of Citizens Vauquelin and
Alexander Brogniart, who found lime in flour, and who cal-
culated that a man who confumes only one pound of bread in
a day will have eaten near two pounds of lime at the year's
end.

" When a man has arrived at the fumroit of his growth, Phyfiologica!

he has no longer occafion for the fame quantity of lime ; hence

it is found abundantly in his urine and excrements; but as this

earth, in the different digeftive pafTages meets with different

3 acids

184 ON THB COMPOSITION AND USE OF CHOCOLATE.

acids which combine with it and form falts, the greater num*
ber of which, fuch as the phofphate and oxalate are but little
foluble, it frequently produces diforders in the moft necefiary
organs of life ; it is known that it is the bafe of moft of the
urinary calculi and arthritic concretion. It is therefore highly
important to the progrefs of medicine, to examine the aliments
which contain this earth, in an oftenfible manner. The Citi-
zens Vauquelin and Alexander Brogniart, found it in abundance
in bread : I have difcovered it in chocolate.

'? Citizen Delaville, in a memoir which made part of the
hundred and twenty-fecond number of the Annates de Chemie,
fays, fpeaking of the fap of cabbages, " this fap evaporated
yields a confiderable quantity of fulphate of lime, the fap of
radithes affords refults nearly fimilar."

" Here then are four aliments which are frequently era-
ployed at the fame time, and which carry into the pafiages of
digeftion a confiderable quantity of lime. Other inftances
might be cited, fuch as ciders ameliorated by the merchants
with chalk, and I have thought thefe facts were not unworthy
of the attention of phyficians. It is the aflerablage of fuch
obfervations, trifling in appearance, which frequently explain
the caufe of the phenomena belonging to phyfiology. Nothing
ftiould be neglected in animal chemiftry, the principal aim of
which is the prefervation of our health and the annihilation of
the moft dreadful maladies which afflict human nature.

VI.

On the Caufes by which the Oxigen of the Atmofphere isfupplied
or renovated. In a Letter from Mr. Robert Harrvp.

To Mr. NICHOLSON.
S I R,

IF you think the inclofed paper of fufficient importance to
meet the public eye, be fo kind as to give it a place in your
valuable and interefting Journal,

I am, Sir,

your obedient humble fervant,
ROBERT HARRUP,
Chobham, June 22, 18Q3,

WHEN

CAUSES BY WHICH THE OXIGEN, &C. ] g5

WHEN we confider the great importance of oxigen in Great import-
the fyftem of nature, its almoft univerfal agency and the im- ance and Pr°d'-
menfe quantities which are every inftant confumed on the fur- tjon 0f oxigerf*
face of the globe, the queftion naturally arifes, from what co- in thefyftcm of
pious fources are we fupplied with this wonderful fubftance inna ure'
a gafeous ftate? As neither animal life nor combuftion can be
maintained one moment without it, the quantity daily de-
ftroyed mud exceed all calculation. To form fome diftant
idea of this confumption, let us endeavour to afcertain the
leaft poffible quantity which muft neceflarily be decompofedin
a given time, in a large populous city. It is proved by expe-
riment, that one perfon confumes about five cubic feet of at-
mofpheric air in an hour, or, in other words, decompofes the
oxigen gas contained in that quantity. Now, if this gas is
taken at one fourth of the whole, it will be found that 100
perfons decompofe 125 cubic feet every hour, and if the popu-
lation of London be taken at 800,000 perfons only, the quan-
tity decompofed every hour, will amount to no lefs than one
million cubic feet. But if this quantity is deftroyed by refpi- Confumption in
ration alone, how much more muft be confumed by combuf-{f°ndo"I2?.mi1*

J lions of cubic

tion in the fame fpace of time. It would indeed be difficult feet in a day.

to afcertain with any degree of precifion, the quantity necef-

fary for maintaining a common fire, but if the combuftion of a

middle fized candle be equal to the confumption of one perfon

by refpiration, it is certainly much under-rating the quantity

if taken at four times that of the former. However, fup-

pofing it to amount to no more, it muft follow that the oxigen

gas decompofed by refpiration and combuftion only, in the

City of London, amounts to the enormous quantity of five

million cubic feet per hour.

Soon after the difcovery of the component parts of atmo- Renovation of
fpheric air, Drs. Prieftley and Ingenhouz thewed by a great^^r.by vegc*
number of experiments, that oxigen gas was emitted by ve-
getables when expofed to the rays of the fun. From this fact
it was immediately concluded, that the atmofphere was princi-
pally, if not altogether, fupplied with oxigen gas from this
fource. This opinion, which ftill obtains without any attempt
to controvert it, appears to me objectionable in feveral re(pe6ts.
In the firft place, it is doubtful if the fupply from this quarter
be at all adequate to the confumption for Dr. Prieftley, like-
wife founcj that vegetables during the night, emitted a gas to-
tally

IStf

fappofed to be
insufficient for

vetfons ft 4 tc»i.

©xlgen abound*
no !efs in the
air over feas,
deferts, and
frozen regions,
as in places
where vegeta-
tion and the folar
influence pre-
dominate the
moil.

CAUSBS BY WHICH THK OXlGtN

tally unfit for refpiration or combuftion, fo that the- oxigen gas
formed in the day would not only be confumed in the night by
thefe proceffes, but a deleterious gas added to theatmofphere.
But fuppofing the quantity of this latter to be fo fmall as to
produce no effe6t, yet it muft be admitted, that while the fun
is under the horizon, none of the former can be produced ;
indeed it is only by the direft influence of the folar rays on
living vegetables that it is evolved at all. How many circum-
ftances then under the temporary deprivation of light, muft
concur to obftrucl the evolution of this falufary fluid from ve-
getation. The inhabitants of countries where fogs or clouds
obftruft the folar rays for weeks, nay months together, muft be
indebted for life to the winds wafting oxigen gas from regions
far diftant from their own, where a perpetual fpring and cloud-
lefs fikies prevail. In the depth of winter, when half the world
lies buried under ice and fnow, and vegetation fuffers a tem-
porary fufpenfion, every living creature in thefe climates muft
be indebted to the fame friendly winds and regions for health
and life.

Thofe portions of the furface of the globe which furnifh
oxigen gas from vegetation, are not only fubject to moft of the
perpetual interruptions already mentioned, but make but a
fmall part when compared with the whole. The vaft tracls
of ocean can afford nothing for the prefervation of animated
beings more than the fandy defect bounded only by the horizon,
or the eternally frozen regions of either pole, and the blafts of
the north would carry deftruclion to all at leaft who inhabit
near the artic circle. It would be only in the torrid zone
where we could expe<5l to find, in fufficient quantity, that life
fupporting fluid, which, unfortunately for the common received
opinion, is as abundant in the midft of London at all times, as
at Nova Zembla, or on the line. As nature, ever uniform,
makes the moft ample provifinn for carrying on her operations
throughout her works, it cannot be ferioufly maintained that
(lie would truft a bufinefs of fo much importance as the pre-
fervation of animal life, to means fo precarious as clear or
cloudy weather, or the viciflitudes of the feafons. The quan-
tity of oxigen gas contained in the atmofphere is found to be
nearly the lame at all times and in all places, whether in the
depth of winter or middle of fmnrner, whether on land or on
water, whether in the crouched city or remote hamlet, but if

the

©F THE ATMOSPHERE IS SUPPLIED. J87

the general opinion were juft, it would be fubject to perpetual

variation. From this fingle fact we infer, that affinity or at- The fupply is

traction is concerned in keeping up a conftantand regular fup- ^[°e^ Jhcmicaj

ply, and that however unequal at different times the con- affinity j

fumption may be, that power will frill continue to act in a

proportionate degree. Several years ago, I conjectured that

the water in a ftate of folution in the atmofphere, or that which

compofes the clouds, might be decompofed by the action of

light, and confequently furniih a fufficient fupply. With this not perhaps

view I made feveral experiments, by expofing water in glafs ntio°n of aqlfeoua

veflels to the influence of the rays of the fun, but could never vapor,

fucceed in producing a fingle bubble of any fort of gas, although

confined with air of different degrees of denfity, and in vacuo,

and expofed for feveral months. At that time I attributed the

want of fuccefs to the difficulty of imitating nature, therefore

did not abandon the idea entire-ly.

Meditating on the fubject fome time after, I conceived it but from the

extremely probable, whatever may have been alledged to the ?jJ?JSi

contrary, that azotic gas has fome degree of affinity for oxi- withoxigen.

gen, and that the combined action of this fluid and light might

be fufficiently powerful to decompofe water. To determine

this point, I made the following experiment, which fucceeded

beyond expectation. Into a fmall tranfparent glafs retort, Experiment.

filled with frefh drawn pump-water, I introduced 17 ounce Azote gas was

. r r expofed to water

meafures of pure azotic gas of the temperature or 56°, and jn an inverted

inverted it into a bottle filled with water, and funk to the neck veffeL
in a pot of fand ; the mouth of the retort defcended to within
about an inch of the bottom of the bottle. After accurately
marking that part of the neck of the retort at which the water
flood, it was placed on the outfide of a window fronting the
fouth, April 22, 1801. On the firlt three or four days of ex-
pofure, a number of very minute bubbles appeared on the fides
of the glafs and rofe to the furface. They after this entirely
ceafed, and the water became fome what turbid. In about
three weeks, having recovered in a great degree its transpa-
rency, an infinite number of fmall yellowifh particles were
uniformly diffufed through it, and which continued to the end
of the experiment. The volume of included gas was per-
ceived to be increafed fome time after expofure, and after fome
days of uninterrupted funjliine. Some time in the beginning of
October, long after the gas had ceafed to gain any additional

bulk.

188

In the courfc of
time the gas was

incrcafed,

almoft one
fourth^

and was better
than common
air.

There was no
hidrogen.

But the oxigen
is never thelefs
thought to have
come from the
water.

Qu. Ifthedeve-
lopement of
oxigen from
water in contact
with azote be
not the reno-
vating caufe in
the atmofphere.

CAUSES BY WHICH THE OXIGEtt, &C

bulk, the apparatus was taken in, and being brought to the
temperature of 56°, I had the fatisfa&ion to find it was in-
creafed confiderably. After marking the neck of the retort
where the water now flood, in order to know whether any
farther change would take place, the whole was placed in a
dark clofet, near which a conusant fire was kept. After (land-
ing till November 23, 1 802, no increafe or diminution had
taken place. Upon examination, the increafe was found to
be fomewhat more than four ounces, as the whole meafured
upwards of 21. It now exhibited all the properties of atmof-
pheric air. A fmall taper continued to burn in a given portion
the fame fpace of time as in an equal quantity of common air.
By feveral trials with Mr. Davy's eudiometer, it was found to
contain a fomewhat larger proportion of oxigen gas then the
air of a large room where the trials were made. And the teft
by fulphuret of potafh (lie wed the fame. What appeared fur-
prifing was, that no hidrogen gas could be found. Its abfence
is not eafily accounted for, I can only conjeclure that the hi-
drogen might have entered into combination with fome extra-
neous fubflance contained in the water, as the oxigen was
evolved particularly, as all that part of the infide of the retort
with which the water was in contact, was lined with a pelucid
whitith film, which came off in large flakes upon rinfing it.
It feems to me extremely difficult if not impoffible, to account
for the oxigen gas produced in this experiment/ otherwife than
from the decompofition of the water. It cannot be fuppofed
that this quantity of gas (no lefs than 4ozs.) was held in an un-
combined flate in the water, which in all amounted to little
more than a pint. That portion of oxigen gas which is found
naturally in water, feems to have been extricated at the be-
ginning of the experiment as already mentioned, which alto-
gether could not have amounted to two drams by meafure at
moll, and no more was obferved to arife. Neither could it
be from putrefaction, as the water was free from fmell, and no
hidrogen gas produced.

Are we to conclude, then, from thefe fa6ls, that by the
combined a6tion of light and azotic gas water is decompofed,
and that when the gas ceafes to act, or is faturated, if I may
ufe the expreflion, no further decompofition takes place till a
portion of the oxigen gas is feparated ? If this be admitted,
we can readily account for the immenfe quantity of oxigen gas

with

REPORT ON A MEMOIR. J'gg

with which the atmofphere muft be necefTarily fupplied to keep
pace with the confumption, and alfo why it is only found in
one invariable proportion.

VII.

Report on a Memoir * fent to la Societc Libre des Pharmaciens,
of Paris. By Cit. Robert, Chief Phyficianto the Hofpital
Of Humanity, at Rouen. By f Citizens C. L. Cadet and
Boullay.

'OITIZEN ROBERT recounts the different experiments Introductory
made by Citizens Fourcroy and Vauquelin, on the erTeds 0f obfervations.
fur-oxigenated muriate of potafli united to certain combuftible
bodies, and fubmitted to the action of a blow or friction ; thefe
brilliant detonations are now known to all chemifts; they are
equally well informed of the inflammations which take place
when the fame bodies are plunged into concentrated fulphuric
acid. Cit. Robert has modified the latter experiments in an
interefting manner. • Inltead of throwing the inflammable mix- cit. Robert's
tures into the acid, he only touches them with a tube wetted experiments,
with this acid. In this manner he inflamed,

lft. Three parts of the fur-oxigenated muriate, and one
part of fulphur.

2d. Three parts of the fame fait, half a part of charcoal,
and as much fulphur.

3d. Equal parts of antimony and fur-oxigenated muriate.

4th. Equal parts of fulphuret of antimony and of the fait.

5th. Equal parts of kermes and golden fulphur (and the
fait.)

6th. Equal parts of arfenic and the fait.

7th. Three parts of the muriate and one of fugar.

8th. Three parts of the muriate and one of charcoal.

9th. A part and a half of the muriate and three parts of
gunpowder.

* The fubjecT: of the Memoir itfelf is the inflammation of com-
buftible bodies combined with fur-oxigenated muriate of potam, by
contact with fulphuric apd. C Ss B.

t From the Annales ae Chimie, Frimaire, An, XI.

And

]9(J REPORT ON A MEMOIR,

And laftly, partes made with alcohol, olive-oil, and fur-*
bxigenated muriate of potafh.
repeated with \ve have repeated all thefe experiments which fucceeded

perfectly, as well as the following, which appeared with reafon
to Cit. Robert, to deferve attention.

He charged a piftol with common gunpowder, and having
primed it with the mixture of powder and muriate mentioned
above, he inflamed it with the fulphuric match *, and it went
. off.
further experi. Cit. Robert obferved, that the report, the colour of the
^complete the ^ame> a°d the odour exhaled by the various combuftibles are
enquiry. eflentially different; but he made no enquiries refpefting the

gafes they formed, or the compounds which remained after
the inflammation. We propofed to collect the gazeous pro-
ducts in a hidro-pneumatic apparatus, for the purpofe of ex-
amining them, but the time appointed by the fociety for mak-
ing our report being but a few days, we have poftponed thefe
enquiries.

Tho* curiofity alone may appear interefted in purfuing
fuch experiments, we have thought it a duty to try, in a fimi-
lar manner, feveral Ample and compound fubftances, the in-
flammation of which had not been before attempted.

New Experiments made by the Commijfwners.

New experi- The manner of operating being nearly the fame, to avoid

meats. the continual repetition of the fame formula, we fhall only

point out the fubftances united with the fur-oxigenaled muriate

Phofphorus. of potafh. Phofphorus prefented beautiful deflagration. Hi-

Hidrogengas. drogen gas took fire. To perform this experiment, we filled

a bladder with inflammable air. To its flop-cock we affixed

a fimple adjutage or copper tube with a fingle jet. We moif-

tened this tube with fulphuric acid, and touched it with fur-

oxigenated muriate of potafh, at the fame time preffing the

bladder to make the current of the gas pafs over the fait. At

the inflant of contact the gas took fire, as if by the eledric

fpark.

Ifculs. Gold, filver, zinc and iron, yielded no other phenomenon

but the decrepitation of the fait alone. We were not furprifed

* The tube and fulphuric acid, Tranflator.

REPORT ON A MEMOIR. \Q\

at this negative refult with the two firtt metals, which are not
eafily oxidable, but zinc and iron promifed an inflammation*
becaufe they detonate by a blow.

Brown oxide of copper, the refidue of the difiillation of Metallic oxide*
acetate of copper burnt without flame, with fparks refembling
thofe from gerbes d'artificc (a kind of firework called the wheat
fheaf.)

Metallic fulphurets fucceeded pretty well, particularly the fulphurets,
fulphuret of tin or aurum mufivium, and the black fulphure of
mercury. The laft yields a very beautiful white flame. Am-
ber, fuccinic acid, bitumen, did not take fire, but the decre-
pitation was very considerable.

Among the vegetable fubftances fome inflamed eafily, fuch Vegetables.
as the volatile oils, refin, turpentine, gum copal *, and gum
elemi, gum arabic, the duft of lycopodium, foap, camphor,
cotton, and fawduft. This laft article did not always fucceed,
but with the addition of a little fulphur it makes an excellent
powder of fufion, which from the facility of its inflammation
by a re-agent, may be ufeful to mineralogies.

We tried ftarch, it inflamed with difficulty, but we fuc-
ceeded in making it burn. Ether takes fire very quickly. We
©bferved that in this experiment as well as in thofe with cam-
phor and alcohol, very little of the fur-oxigenated muriate was
decompofed, and it did not burn, but was folely of fervice to
favour the inflammation. To afcertain that fad, we mixed
fulphur with the refidue of the experiment, the fulphuric match
produced a fecond eombuftion.

We made a paite with the fur-oxigenated muriate and
honey; this mixture caught fire, fwelling up and emitting an
odour of boiling, fugar mixed with a very penetrating acid,
which one of us believed to be acetic acid.

Chryfiallized benzoic acid diffufes a confiderable reddffli
flame; tartareous acid and acidule burn alfo very well; tar-
trite of potafh offers a beautiful whitifli flame; tartrite of foda
prefents neither inflammation nor light. Antimoniated tartrite
of pjtaih gives beautiful fparks without flame.

Oxalic acid with the oxigenated muriate fparkles without

* The gum refin, copal, ftill but little known, has been aflimi-
lattd by feme chemifts with amber. This experiment eftablimes a
very remarkable difference between thefe two iubfrances.

inflammation.

\QC2 REPORT ON A MEMOIR.

inflammation. Acetic acid produces a confiderable deflagra-
tion and a beautiful blueilh flame. The acetates of potam
and foda take fire with crackling.

Animal matters. Thefe refults induced us to examine what animal matters
were fufceptible of burning by the lame proceffes ; we tried
dried gluten and hartfliorn (havings without fuccefs.

The yolk of an egg, wax, butter, tallow and greafe, burnt ;
like oil, but with lefs crackling; wool and a piece of rabbit's
fkin with its fur on, ftrongly impregnated with fur-oxigenated
muriate of potafh, were inflamed and continued to burn until
their total incineration.

Singular refults. Among thofe experiments which prefented us remarkable
Angularities, we muft mention the fulminating powder which
we could never fet fire to, though it was decompofed with a
confiderable difengagement of gas and heat. Three other
mixtures with metallic bafes furprifed us greatly by their ter-
rifying detonation, by their rapid inflammation, and by their
ftronor efTeCr. in fire-arms*. Cil. Robert has no doubt tried

o

them, but he makes no obfervation on them. We fhall copy
his referve, and only allow ourfelves two remarks. The arms
are ftrongly oxided and foon deftroyed by thefe mixtures,
which are expenfive and more difficult to prepare than gun--
powder; we think they are not capable of being granulated.
Their inflammability would render their carriage and their ufe
too dangerous, fince a blow or frifiion produces detonation.
We (hall conceal their names, becaufe malevolence too often
abufes the fatal fecrets made known by chemifts. The re-
membrance of the calamities at Eflbne, ftill more the public
falety makes it our duty to be filent, and not to give a new re-
fource to the cruel art of deftroying mankind.

* They take fire like powder by the fpark from a gun flint.

Defcription

DESCRIPTION OF A TELEGRAPH USED IN SWEDEN; 195

VIII.

Defcription of a Telegraph ufed in Siveden. Conftrucled by Sir
A. N. Edelcrantz, CounfeUor of the Chancery, and pri-
vate Secretary to the King of Siveden, Archivift of the Orders
of His Majejiy, and One of the Eighteen Members of tht
Swedifh Academy. From the Copy of a Treatife on Telegraphs,
communicated by the Author.

x\FTER numerous obfervations on the various defcriptions Qualities requl-

of fignals, and an hiftorical detail of the ufe of them, from the flte !" a te,c"

. graph j

raoft remote antiquity to the prefent time, the author ftates

the principal qualities of a good telegraph to confift in :

1. Perfection in the principle of the machine, and in the
nature of the fignals.

2. Perfection in the means employed to work the machine;
The firft of thefe requires : 1. a fufficient number of fignals

to exprefs not only letters, but alfo fuch words and phrafes as
are in general ufe : 2. that the fignals (hall be fo apparent;
that any one may fee them very dillinclly : 3. that the appli-
cation of the fignals to their refpeclive fignifications (hall be
«afily underftood and retained «

The fecond requires : 1 . the leaft poffible weight and fric-
tion of the parts : 2. quicknefs in the movements and changes
of the fignals : 3. certainty to prevent miftakes and ambiguous
remits.

The credit of uniting all thefe qualities in one machine, are firft united by
afcribed to M. Chappe, the inventor of the French telegraph, M* ChaPPe« •
of which he gives a defcription. The number of fignals it is
capable of, allowing the angle of inclination of its refpective
arms to be 45°, is 256 ; by diminifliing that angle to 30° they
may be increafed to 864, and in like manner the number may
be ftill further augmented by every diminution of the angle,
but the fignals would be proportionally lefs diftincl.

When this difcovery was announced, the learned of all coun- Attempts to
tries inftituted enquiries into its principles and conftru&ion. difcoverthecon*
Among others, the Chevalier made various machines, fome pr;ncjp]es 0f ^
refembling the French telegraph, and others totally different, French tele.
and after many attempts he fucceeded in conftru&ing thatgrap
which is the principal fubjeft of his treatife, and to which he

Vol. V. — July. O gave

\94f , DESCRIPTION OF A. TELEGRAPH USED IN SWEDEN,

Advantages of gave the preference, becaufe it occupied lefs fpace, was more
b^the^hor. raP^ anc* eafy m "s movemenls, more certain and unequivocal

to the fight, and, to all its other advantages, added that of

being ufeful by night.

Defcription of the Machine.

Defection. a, b, c, d, e, f, (Fig. 1, PI. XII.) is a frame of wood, in the

openings of which are placed ten mutters at equal diflances
from each other, in three vertical ranks, that in the middle
confiding of four (nutters. Thefe (butters, which mould be as
thin as poffible, may be made of wood, iron or copper, and
are fixed on an axis on, the extremities of which move in holes
made in the frame. On the axis on, perpendicular to its di-
rection, but with an angle of 45° to the furface of the fliutteF
is a fmall arm ms, from one extremity of which a firing de-
fcends to the bottom of the frame, by means of this and of the
arm ?ns, the (hutter receives at pleafure a vertical or horizontal
pofition. Fig. 1 reprefents all the (hutters in a vertical pofi-
tion, and Fig. 4 (hows the profile of the machine, the (butters
being horizontal. It will be eafily feen, that when the (hutters
which are very thin, are obferved from a diftance and horizon-
tally, they will be fcarcely perceptible ; but they become vi-
fible, if, by drawing the firing s k, a vertical pofition is given
to them. When the machine is at reft, the (hutters are kept
in a horizontal pofition by a weight q attached to them at /,
and are fupported by the pin p I. In the other pofition they
are kept upright by a piece of wood p place behind them, but
which is mown in front in the plate. To prevent the firings
from getting entangled, the arms ms are fixed at unequal dif-
tances from their refpe&ive (hutters. The (Irings pafs through
holes made in the crofs plank ur, or uuu, (Fig 2.) which
(hows the plan. They may then be made to pafs through the
plank wxv, and be fecured to ten rings tt, each correfponding
to one finger, by which means a fmall machine may be conve-
niently worked.
Number of its According to this conftruction, 1024 combinations or dif-
iTgnah. tin6t fignals may be formed by raifing or lowering the (hutters.

The better to diftinguifii them they are exprefled by numbers
on the following principle. Leaving out the upper (hutter A,
the machine will confift of three vertical lines, with three (but-
ters on each. To the upper (butter of each line give the value
4 of

DESCRIPTION OF A TELEGRAPH USED IN SWEDEN. \Qj

of lt to the fecond 2, and to the laft 4, and from the value
of the tingle (nutters form that of their combinations. Thus
when the firft and fecond mutters on a line are vifible, they
will fignify 3 = 1 + 2, the firft and third 5 = 1 + 4, the
fecond and third 6 = 2 + 4, and the three together 7 =
1 +2 + 4, and in the fame manner for each vertical line.
If in any of the lines no fhutter is vifible, the vacancy is ex-
prefTed by o. Thefe three lines give 5 1 2 different fignals,
and the number is doubled by the addition of the fhutter A.
Thus in expreffing the number of the fignal, fuppofe the firft
and fecond fhutters of the firft line to be feen, all three on the
fecond line, and none on the third, the value muft be written
370, if to thefe the fhutter A is added, the number muft be
exprefTed by A 370, and fo of every other combination. On
the left fide of the machine is placed an arm H, the ufe of
which is partly to direct the arrangement of the lines, begin-
ning from that fide ; and partly to point out the middle fhutter
in each line. It may be made moveable on hinges, and can
then be concealed or made vifible at pleafure. It will be
eafily conceived that the method of valuing the lines may be
varied by agreement, fo as to be reckoned from right to left,
or horizontally, in either direction : thus the pofition of the
telegraph as indicated above, may be exprefTed by 370 —
670 - 073 - 076 - 662 - 266 - 332 or 233, but the me-
thod firft defcribed feems to be the moft natural.

By the mode of reckoning, the value of the fhutters as de-
fcribed above, it will be feen that they are capable of expref-
fing every number of three places, from 000 to 777, which
does not contain an eight or nine. To make ufe of thefe num-
bers, a table muft be conftructed on the following plan.

O 2

\96

DESCRIPTION OF A TELEGRAPH USED IN SWEDEN.

Table of
cyphers.

000

100

200 and fo on

000 - - - 777

100 - - - 677

200 - - - 577

001 776

101 - - - 676

201 - - - 576

-

002 775

102 - - - 675

202 - - - 575

003 774

103 674

203 --- 574

004- - - - 773

104 - - - 673

204 573

005 - - - 772

105 - - - 672

205 - - - 572

006 - - - 77 1

106 67 1

206 - - - 571

007 770

107 - - - 670

207 - - - 570

010 - - - 767

1 10 - - - 667

210 567

Oil - - - 766

111 - - - 666

211 - - - 566

012 - . - 765

112 665

212 - - - 565

013 764

113 664

213 - - - 564

014 - - - 763

114 - - - 663

214 - - - 563

015 762

115 662

215 - - - 562

016 - - - 761

116 661

216 56]

017 - - - 760

117 660

217 560

020 757

120 657

220 - - - 557

021 756

121 - - - 656

221 -' - - 556

022 755

122 - - - 655

222 555

023 754

123 654

223 554

024- 753

124 - - - 653

224 553

025 752

125 652

225 - - - 552

026 - - - 751

126 - - - 651

226 - - - 551

027 - - - 750

127 650

227 550

completing the feries in each direction until the whole number
of combinations are expreffed, and tilling up the vacancies be-
tween the double row of numbers with fuch letters, figures,
words or fentences, as may have been previouily agreed upon,
its ufe by night. The two rows of numbers are only neceflary when the tele-
graph is intended to be ufed by night as well as by day, in
which cafe it mult be obvious, that when the concerted fignal
is made by raiting the mutters, thofe lights which ate placed
behind them, as will be defcribed hereafter, become hid, and
the value of the fignal is reverfed in confequence of the open
fpaces being vifible inflead of the clofed ones.

A fecond table muft alfo be formed to contain the fame feries

with the letter A prefixed as defcribed above.

The correfpond- When the correfpondence requires fecrecy, the fignifica-

ence may be tions of thefe numbers, and the methods of eftimating their

value may be varied almoft to infinity by any one verfed in the

knowldge

DESCRIPTION OP A TELEGRAPH USED IN SWEDEN. 197

knowledge of cryptography. Several plans of this kind are
inferted by the Chevalier, the details of which would extend
the limits of this paper too far.

Methods of working the Machine.

It has been already noticed, that a fmall machine may be Methods of
worked by the rings tt, but as the ftrength of the fingers arewor ms*
unequal to the weight and refiftance of a large machine, more
powerful means muft be had recourfe to. With this view the
author propofes to replace the rings with metal rods affixed to
the firings, and having a button at the lower extremity of each.
To work the machine fo prepared, he propofes to have an in-
ftrument of iron nearly in the form of a T, at the bdttom of
which (hall be an opening or ftirrup to receive the foot. The
crofs arm of it is to have ten notches correfponding to the ends
of the rods, and is to be kept on a level with them by a weight
behind. When a lignal is to be made, the ends of the rods
hanging to the mutters which are to be clofed, are flipped into
their refpe&ive notches, and the machine is worked by pref-
fkig down the inftrument with the foot. When the lignal has
been obferved the foot is withdrawn, and the inftrument re-
fiored to its original pofition, by the weight which has been
defcribed. The rods are then difengaged, and the whole is
in a fiate of preparation for the next lignal. This may be
more expeditioufly performed by another contrivance formed
of ten plates of metal moveable on a common axis, and each
having a hollow in its outer edge. When the machine is at
reft, thefe plates are in a vertical pofition, and the box con-
taining them is placed before the lower ends of the rods. To
make a fignal, the plates correfponding with the rods intended
to be acted on, are pufned with the fingers into an horizontal
pofition, and the box Hid along in two grooves made for the
purpofe, by which means all thofe rods are prefled into their
refpeclive notches at once, and a confiderable fpace of time
is faved, while the rods whofe correfponding plates retain their
vertical pofition are unmoved. If a ftill greater force is re-
quired to work the machine than can be obtained by the foot,
a winch with rackwork, or with a pulley, inftaad of the up-
right bar of the inftrument, may be applied to the crofs arm.

In order to afford more perfpicuity in making a lignal, the Each fignal may

Chevalier alfo propofes to form the combinations of each re- be made by

r ~. drawing one rod

fpeQro&-fcjrte

TQg DESCRIPTION OE A TELEGRAPH USED IN SWEDEN.

fpecVive line by means of united firings, thus to reprefent I
a firing attached to that.fhutter is faflened to a rod numbered
1 ; for 2, a llring is brought from that fhutter to a rod num-
bered 2; but to produce 3, a firing from each of the fhutters
1 and 2 is affixed to the rod numbered 3, and in a fimilar
manner 5, 6 and 7, are each produced by combining the firings
before they are united to the rods. In this method the num-
ber of the rods are increafed to 22, but as only one of each
line can be ufed at once, and they are all numbered, there is
lefs probability of a miflake, and the quicknefs of the opera-
tion is increafed.
Requires only According to the conflruction above defcribed, it will be
one or ^per- feen ^^ one perfon js fufficierit to work the largeft telegraph
at the extremities of the line of flations, provided the telefcope
is fo placed that he can look-out and work the (nutters at the
fame time ; but in the intermediate flations, where the obferva-
tions mull be made with two telefcopes, in contrary directions,
who need not there Ihould always be two perfons who may relieve each other,
be men of jt js not reqUifiie that they mould be men above the common

rank ; all that is wanted of them is to be able to write down
the numbers, and to combine 1,2, 3, 4. In the attempts
Children made by the Chevalier, he, during a year and half, employed

employed. on\y children, and a very few hours were fufficient to give

them a complete knowledge of what was required of them. It
was for this reafon he was induced to facrifice ibmething of the
limplicity of the mechanifm to fimplicity in the execution.
When thofe employed are not well fkilled in the ufe of the
machine, it is important not to load their memory or their con-
ception with too many details, and it is probably to this as
much as to rapidity of execution that the chief merit of this
telegraph is owing.
Theobfervatory. The obfervatory fhould always be placed below the tele-
graph, and fhould enclofe the telefcopes and machinery with
which the telegraph is worked. It ought to be as much dark-
ened as poffible, and painted black withinfide, in order that
all foreign light may be excluded, by which means the impref-
fion of an object is rendered much more diflincl to the eye.

Methods of vfing the Telegraph by Night.

Methods of For the purpofe of rendering the telegraph ufeful in the

ufmg the tele- night, the following plans are adopted.

graph by night. r

DESCRIPTION OF A TELEGRAPH* USED IN SWEDEN. ] Q$

In the firfl it is propofed to place a lamp behind each (hut- Firft plan.
ter at fuch a diftance as not to obflruct the movements, and
rather above the axis. In this method, by doling the fliutters
according to the plan indicated above, the lamps correfpond-
ing to the fhutters which are railed will difappear, and thofe
"which remain vifible will form a fignal the reverfe of that in-
tended, the value of which will be found on the right fide of
the table of cyphers defcribed before; hence the day fignal
will be before the fignification, and the night fignal after it.
But as this plan was found to be inconvenient in practice, or at
great difiances the following was fubflituted for it, a, b, c, d, Second plan.
(Fig. 3.) is a tin lanthorn having only two openings e, to
permit the pafiage of the light ; placed on oppofite fides, and co-
vered with talc or mufcovy glafs. Between thefe two openings
a good lamp is fituated fo as to give light in both directions.
g,f, k is a quadrant of tin adapted to each fide of the lanthorn,
and moveable on its axis h, in fuch a manner, that by means
of a firing attached to the arm 4 it may be raifed before the
openings of the lanthorn, but falls again by its own weight
when the firing is let go. Ten of thefe lamps are to be fixed
on a frame in a fimilar manner to the ten fhutters ufed by day,
the firings depending from each are united at the foot of the
machine, according to the fame principles and the fame com-
binations as in the day telegraph ; but as the weight and fric-
tion to be overcome is much lefs, this machine may be worked
at all times with the hands alone. One advantage which this
eftablifhment poflefles over the day telegraph is, that it does
not require to be placed above the horizon, it is even better
to be below it. Befides, in every point of view it is more
eafily worked and is much fuperior in utility to the telegraph.

It is known that the fiars rrfay be feen in the middle of the probable vlfibi-
day from the bottom of a deep well ; it remains to be proved, Jjty,°f thg lamp8
if, by a fimilar effect the lamps can be feen in the day-time
with the aflifiance of very long tubes : fhould this be practica-
ble it will be highly advantageous in many refpe6te, particu-
larly in requiring only one eflablifhment for both purpofes.
By means of the equatorial telefcopes of Short or Ramfden,
the flars may be obferved at noon even clofe to the fun, hence
it is probable that if all foreign light is excluded, the lamps
will be vifible on a dark ground. Telefcopes which magnify
the mofl will be preferable, becaufe they darken the field of

view

200 DESCRIPTION OF A TELEGRAPH USED IN SWEDEN,

view more than thofe of fmaller power, without diminifhing
the impreffion of the light on the eye in any confiderable de-
gree.

Ufefulnefs of Opinions are divided on the utility of telegraphs, and fome

eSraP s> 0f tne;r opponents found their arguments on the alterations
to which the tranfparency of the air is liable, and which im-
pede their ufe. But the art of feeing through fogs and dark-
nefs will perhaps never be difcovered. It will fcarcely be
contended that navigation is a ufelefs fcience, becaufe winds
and tempefts fometimes impede it. Others confider the ex-
pence of telegraphs as too great in proportion to their utility.

to goyemments. But independent of the advantages arifing to every govern-
ment, in being enabled to tranfmit its orders to the extremities
of the kingdom in lefs than a quarter of an hour, and to be
no lefs expeditioufly informed of what is paffing on the fron-
tiers, it is in time of war, when events occur on the know-
ledge of which the fafety of thoufands may depend, and which
require precautions as prompt as vigorous ; it is in fuch a pe-
riod that the value of telegraphs is incalculable, and their coft
bears no comparifon with their utility, particularly if the ex-
pence of couriers faved by their means is taken into the ac-
count. It may be added, that the ufe of thefe machines in
France during the late war furnifhed inconteftable proofs of
their utility.

There are two ways in which this machine may be ufeful ;
the firft, when a quick communication between the two places
is required ; and the fecond, when this communication is not
practicable in any other way. The poft goes from Sweden to
Finland in five days, but if the diftance was divided into tele-
graphic ftations, intelligence might be conveyed in three or
four minutes. Should the poft be retarded or interrupted either
by the obftacles of the feafon, by the infecurity of the lakes,
or by contrary winds or tempefts, the communication may be
kept up with the cuftomary expedition of the poft, by form-
ing ftations in thofe places where the principal obftruclions are
met with, fuch for example as the fea of Aland ; or with the
greateft rapidity, by placing them along the whole road,
to fcience. From every appearance it is expe&ed that natural philofo-

phy will acquire many important benefits from thefe eftablifh-
ments. Every telegraph is a real obfervatory, which, with
the affiftance of fome inftrument, and the requifite information

m

1

OBSERVATIONS ON ERUPTIONS OF LUNAR VOLCANOS. C20\

in thofe who govern it, might enrich the fcience with new
difcoveries. An acquaintance with the effects of the re-
fraction of the air might be difleminated by daily experiments ;
meteorology, which is the leaft cultivated, and perhaps the
moft difficult branch of natural philofophy, might be ftored
with difcoveries on the influence of heat and cold, humidity,
ftorms, changes of weather, fogs, fnow and rain, as well as
that produced by feveral other meteors on the tranfparency
of the air ; a daily comparifon of the indications given by
the barometer, the hygrometer, the anemometer, and the
electrometer, with thofe of the diaphanometer of M. de Sauf-
fure *, and of the cyanometer t, might, in time, lead to very
unexpected refults.

At the conclufion of the work, the chevalier notices the Englifli tele-
telegraph erected on our admiralty, which appears to have SraPh«
been an invention fubfequent to his, and to be Jefs complete.
His telegraphs were eftablifhed in Sweden in 1794, ours was
not erected until 1796, and the number of its fignals does
not exceed 64, unlefs thofe are reckoned which depend on
the order in which the mutters are fliown, and which ar«
liable to great ambiguity.

IX.

Additional Obferrations on the Probability that the Eruptions of
Lunar Volcanos may fomttimes reach the Earth, By a Cor-
refpondeut.

To Mr. NICHOLSON.
SIR,

uOME time ago, I addrefled a letter to you, on the pro-
bability that the eruptions of lunar volcanos may fometimes reach
the earth ; which was inferted in your Journal for December
laft. I will now beg leave to trouble you with a few additional
obfervations on the hypothefis, I there ventured to advance.

* EJfayfur VHygrometrie, §371.

+ S£e a defcription of this inftrument in obfervations fur la
jphifique et fur l'Hiftorie Naturelle, par Roller, 1791, mars, p. 199.

In

202 OBSERVATIONS ON ERUPTIONS OF LUNAR VOLCANOS.

More particular jn fig. 4, p]ate x. fuppofing E and M to be the centers
the probability °^ l^e earth and moon ;PQK to be a path which a body muft
of projeftiles defcribe, fo as to be equally attracted by both ; it will appear
Mrth8tot£ thC evident from a very eafy calculation, that, P Q K is a circle
moon. vvhofe radius C P is equal to about 24£ femidiameters of the

moon, and the diftance of whofe center C, from the center
of the moon, is equal 2T femidiamelers (nearly).' If there-
fore, the lunar volcanos in any part of the hemifphere of that
planet, which is vifible to us, mould project bodies with a
force fufficient to carry them through 24 of her femidiameter$ ;
i. e. with a velocity of about * 7000 feet in a fecond, they
muft neceflarily throw them within the fphere of the earth's at-
traction. It may be faid, however, that the atmofphere of
the moon, although rarer and of lefs altitude than that of the
earth, may yet be con liderable enough to afford fome refiftance
to the motion of bodies ; allowing, therefore, (the utmoft
that can be allowed) that a body projected from a lunar
volcano, has a refiftance equivalent to that of two miles of an
atmofphere of equal denfity with ours, and fuppofing the
velocity of projection to be 12000 feet per fecond, and the
body to be a fphere whofe diameter is one foot, and fpecific
gravity 10,000 times that of the atmofphere j it would lofe
in its paffage lefs than T of its firft velocity, and would ftill
retain more than fufficient force to carry it within the fphere
Terreftrial vol- 0f tne earth's attraaion. That the volcanos of the earth
duce^the re- throw out heavy bodies with a force at leaft equal to this,
^uifite velocity, feems eafily proved; for a body fuch as we have fuppofed,
if proje&ed upwards with the above-mentioned velocity,
would rife to the height of about nine miles from the earth's
furface, in a medium of equal refiftance with our atmofphere.
It may be objected, that the atmofphere becomes confiderably
rarer at that height, fo as to render the calculation of the
effect- of refiftance greater than it would be in reality ; this,
however, may be more than counterbalanced by the effect of
the elafticity of the atmofphere, and of the vacuum produced
by bodies moving with fuch very great velocity. That volcanos
frequently during an eruption, throw up heavy bodies to the
height of eight or nine miles, will, I believe, be acknow-

* It was by rniftake that I ftated in my laft letter, the velocity
ceceflary at 12,000 feet per fecond.

ledged.

DESCRIPTION OE AN ANCIENT LOCK. 203

ledged. I will now conclude with an attempt to anfwer your
objection, from the bodies being in a ftate of ignition when
they fall to the earth. As the fpace between the earth and
moon muft be either nearly, or altogether a vacuum, it rouft
be almoft, if not quite, a non-conduclor of heat ; fo that it
may eafily be conceived, that a body paffing through it, may
retain during its patfage of about four or five days, nearly
the fame degree of heat with which it fet out, efpecially as no
change of texture takes place, by which its heat can become
latent.

I remain,

Your's, &c.
Cambridge, May, 2Uh, 1803. , J. B.

P. S. For the principles of the estimations, which I have
made of the refinance of the atmofphere. See Alzuood on
Recldinear Motion, fed. 5th.

Defcription of an Ancient Lock of Combination. W. N.

1 HE lock delineated in Plate IX. is fixed in the lid of an Secret lock of
old brafs money box for the pocket ; from which Mr. Lathamofan old money
King Street, Soho, who deals in articles of curiofity, permitted
me to make a drawing.

Fig. 1. is a perfpeclive view of the box, which meafures Defcription and
about three inches in diameter. Fig. 2. fhews the outfide ofdrawin8'
the lid, at one edge of which is a hinge, and upon the outfide
are figures of the fun, the moon, and two clock faces with
hands. The figure of the moon can be Aided nearer or farther
from the center, and carries a bolt placed within the lid. The
other three parts, namely, the fun and the hands of the clock,
can be moved round their center pieces, and left in any
fituation at pleafure. Fig. 3. (hews the infideof the lid. The
bolt which is moveable along by means of the figure of the
moon, is here feen with three tails, pointing to three
circular pieces, in each of which pieces there is a notch to re-
ceive its correspondent tail. Thefe pieces move round by
means of the three parts on the other fide, and it will thence be
eafily underftood tljat the bolt cannot be Hided back, nor the

box

204 DESCRIPTION OF AN ANCIENT LOCK.

box opened, unlefs one particular point of the fun, and each
of the hands be duly placed from a knowledge of the fecret.
And as there are twelve points to' the fun, and twelve marks
for the hours on each dial, we may (without confidering the
probability of intermediate pofitions) reckons the chances
as eleven to one, againft fetting the fun to the proper pofilion;
and eleven times ftill more againft fetting the fun and face of
The fecret of t^e dials right at the fame time ; and again eleven times more

the lock is fe- . * ° , ■ °

cureasi33itoi. againft all thefe being duly fet at once. That is to fay, the
chances are 11 times 11 = 121, taken 11 times or = 1331.
And confequently the lock is very fecure.

As I hope foon to give a fhort eflay on locks, I (hall only
make a few remarks on the prefent machine. In the firft

Cardan's lock. p]ac^ it may be not iced that this> like the jock of Cardan *,

which confifts of four or more rollers, is a fecret lock, and
not a lock of combination ; this laft term being ufually applied
Sacret locks and to locks in which a fecret can be changed through a great
binatkxn. number of varieties, at the pleafure of the owner. And,

fecondly, that it has a practical defect very common to all
fecret locks; namely, that a ikilful examiner may difcover
the fecret, if the workmanthip be in the fmalleft degree in-
Thc prefent accurate. In this manner I opened the prefent lock, at the
opened. * very nr^ trial. ^ tne tnree notched pieces be not truly

circular, and the motion of the bolt extremely precife, and
the lengths of the tails accurately adjufted, one of thefe tails
will bear before the other. I therefore prefled the bolt back,
by urging the figure of the moon towards that of the fun, and
then turned the three pieces round one after the other. Two
of them moved freely round, and the third gave notice when
the bolt fell in, and confequently told its fecret. Of the re-
maining two pieces, one moved freely, and the other hung
and (hewed its pofition. And laftly, the third then required
only to be moved till the bolt took its notch, and went quite
back.
Bot It may be This lock could be eafily made fafe, by adding mort teeth
roadefafebya t0 the infide pieces all round, and making the tails of the
2aagel.S DoIt terminate in fmall projections adapted to take between

thofe teeth. By this contrivance, the tentative procefs of
turning the pieces would be rendered impracticable.

* The fecret padlock of four rollers is fold at our ironmongers.
I bought one at Downer's in Fleet Street, for fixteen pence.

It

ANALYSIS OP A PULMONARY CALCULUS. 205

It would alfo be eafy to make it into a true lock of com- And alfo ex-
bination ; by making each of the circular pieces to confift of combinations.
two equal pieces, locking into each other by contrate teeth,
and fcrewed together by a nut. And if one of thefe pieces
were permanently fixed to the axis, and the other were to
carry the edge-teeth, and notch, as mentioned in the laft .

paragraph, the lock would not only be fecure from opening
by the method I ufed ; but it would" alfo be in the choice of
the pofTeflTor to vary the fecret of the portions by unfcrewing
the nut, and changing the application of the contrate teeth,
after which he would fecure them together as before.

XI.

Andy fis of a Pulmonary Calculus, by Philip Crampton,
M. D. Member of the Royal College of Surgeons in Ireland.
Communicated by the Honourable George Knox.
F. R. S. M. R. I. A. %c *.

ME apology feems necefTary for offering the analyfis of a Difficulty of ob-
fingle pulmonary concretion, but the difficulty of procuring tam»ng puimo-
thofe fubftances, and the importance of every facl, however
infulated, which relates to the changes that take place in the
bodies of living animals mutt plead my excufe.

I have no where been able to find a detailed analyfis of They have not
pulmonary calculi ; Mr. Fourcroy mentions them in a general been examined,
way, as being fimilar to lachrymal, pineal and fali vary con-
cretions, all of which he fays are compofed, as might be ex*
peeled a-priori, of phofphate of lime (either from a fuper*
abundance of that fubftance in the fluids of furfaces, or in the
blood)

But as the calculus in queftion neither agrees with any of
thofe in its external characters, nor in its chemical compofi-
tion, without in the lead calling in queftion the accuracy of
Mr. Fourcroy, I fhall briefly ftate the refult of my own ex-
amination of it.

The calculus which is the fubject of this paper, was taken Defcriptlon an<J

from the lungs of a deceafed foldier, in the year 1796, and niftory °f a

pulmonary cal-
culus.
* Read before the Royal Society in Auguft 1802.

2 was

«20fl ANALYSIS OF A PULMONARY CALCULU9.

was depofitcd in the mufeum of the Royal College of Surgeons
in Ireland, It was irregularly fpheroidal and meafured about
6| inches in circumference. It appeared to be formed of fhort
thick branches, proceeding from a folid center ; its fracture
was laminated, of a pure white colour, fmall communicating
canals appeared to interfect its fubftance in every direction *«
The faw cuts it with difficulty ; 10 grains afforded an
analyfis.

grs.
It wns carbonate 3.7 carbonic acid.

4.5 lime.

1 .8 albumen and water.

of lime.

10.0.

The analyfis. I fliall not trefpafs on your time by detailing the procefs of

fo fimple an analyfis, fuffice it to fay, that it diffolved with
effervefcence in the fulphuric, nitric, muriatic, and acetic
acids, leaving fome floculi of coagulated animal matter (pro-
bably albumen) floating in the liquor of folution, the gas
which was extricated precipitated lime from lime water, and
the quantity of carbonic acid was afcertained, by adding a
known quantity of muriatic acid to a certain quantity of the
calculus, and taking the lofs after effervefcence for the weight
of the carbonic acid which was extricated. A portion of the
calculus expofed to a low heat affumed a blackith hue, but
when fubjedted to a white heat for 20 minutes, it became of
a brilliant white colour. The refidium was found to confifl

Other calculi of pure lime. Morgani Epift. 17 to 19 upon the fubject of
pulmonary calculi, fays, that he has feen many of thefe fub-
itances coughed up, that they were light and porous like
pumice ftone, and varied from the fize of a millet-feed, to
that of a pea ; but he once faw a calculus which had been taken
from the lungs of a perfon who had died of Thifis Pul-
monalis, which weighed 20 grains, was " hard and heavy
like marble." Dodenius faw a pulmonary calculus taken after
death from the lungs of a nobleman, which affected the fhape
of the bronchia?, having fhort thick branches proceeding
from it, and canals which interfered it in every direction.
Morton faw fmooth cretaceous ftones taken from the lungs,
Morgani Epift. XV. 23.

* Apparently formed by the depofition of calculous matter upon
the bronchial veffels.

refcred to.

ANALYSIS OF A PULMONARY CALCULUS. 207

It would appear thence that there are at leaft two kinds of Probability that
pulmonary concretions: thofe which Morgani obferved tobe*"^^^
thrown up by coughing, anfwer the defcription of the the carbonate
calculi, examined by M. Fourcroy, and thofe it has been ^J^?hofphate
ftated were compofed of phofphat of lime, while the con-
cretions which Were hard and heavy like marble, it is pro-
bable agree in their chemical compofition, as well as in their
external characters with the calculus, which is the fubject of
this paper ; this it has been proved was compofed of carbonate
of lime. A queftion then naturally arifes, as to the forma-
tion of carbonate of lime in the lungs. Was it depofited as
fuch from the blood or formed in the Bronchia? by the chemical
combination of its principles ? We have certainly not hitherto
been able to detect carbonate of lime in the blood, and we
have no reafon to fuppofe that the phofphat or lime which
exifls in it, can be decompofed by the carbonic acid which
is formed in the lungs, to avoid thefe alternatives, the chemical
phyfiologift might be inclined to look to an external caufe for
the formation of this extraordinary fubftance, and with this
view, he would enquire into the previous occupation of the
perfon from whofe lungs it had. been taken ; but he would be
checked in his enquiries by the recollection that the fame
chemical affinities which can form carbonate of lime in the
teeth and bones, may by an accdental coincidence depofit
it in the lungs.

XII.

Of the State of Vapour fubfijllng in the Atinofphere. ^j/Richard
Kirwan, Esq. LLD. F.R. S. and P. R. LA *.

V APOUR or moifture in the atmofphere may fublift in denfe The fubfiftence
air, or in air highly rarified : that it is found in the former is J^2«S in*
well known, and that it may fublift in the latter appears by the highly rarefied
obfervations of Bouguer, for he faw clouds three or fourhun-air*
dred toifes above Chimboracho, and confequently at the
height of twenty-two thoufand five hundred and twenty-eight
Englifh feet, or 4,3 miles over the level of the fea ; a height

* From his eflfay on the variations of the atmofphere j In the
Irilh tranfa&ions, Vol. vin\

at

208

Latent Heat of
ft earn.

— is lefs the
greater its
temperature*

STATE OF VAPOUR SUBSISTING IN THE ATMOSPHERE.

at which in the temperature of 32Q a barometer would Hand
at 12,7 inches. At fuch heights, and at much inferior, fince
evaporation proceeds much more quickly, it is not to be fup-
pofed that all the vapour fo rapidly produced is diflblved in the
ambient air, but part rifes uncombined as it does under an ex-
haufted or half exhaufted receiver, and in this' cafe Mr. De
Luc's fyftem is admiffible. This emiflion of pure vapour feems
to begin at heights at which the denfity of the air is 25 (that
is at heights at which the barometer would ftand at twenty-five
inches, and thus I fhall in future exprefs the various denfities
of air,) at lead it is very confiderable where the denfity is
twenty, as already feen, p. 309. This leads me to treat of
the properties and ftate of pure invifible vapour, namely, its
fpecific heat, elafticity, and fpecific gravity.

The immortal Doclor Black, the father of all difcoveries of
this kind, informed me that the vapour of water, boiling at
212°, that is at 180° above the freezing point, and pofleffing
the fame fenfible heat as the water, contains nine hundred and
forty times more latent heat than an equal weight of water
does heated to 212°, or 5,222 times more latent heat than it
does of fenfible heat, counting from the freezing point, for
180 x 5,222 = 940 nearly. In this cafe the preflure or den-
fity of the atmofphere is thirty, the barometer Handing at the
height of thirty inches; and with Doclor Black's account the
experiments of Mr. Schmidt of Gieflen very nearly agree,
for according to him the latent heat of the vapour of water,
barometer 29,84 inches, and the heat 212°, is 5,33 times
greater than its fenfible heat above the freezing point, now
180 x 5,33 = 959*4*. The difference or excefs in his
experiment proceeds from the preflure of the atmofphere being
fomewhat lower, as Mr. Watt's experiments prove.

Mr. Watt difcovered that the latent heat of fieam diminifh-
ed in proportion as its fenfible heat increafed, Phil. Tranf.
1784, p. 335. Now the fenfible heat of fleam exceeds 180Q
above the freezing point when the barometer fiands above
thirty inches, and is lefs than 180° when the barometer ftands
lower than thirty inches, as Mr. De Luc firft. difcovered, and
may be feen in Sir George Shuckburgh's, and*Mr. De Luc's
tables, Phil. Tranf. 1779. p. 375. From thefe I have deduced
the following table:

* 4 Gren's Phys. Journal, p. 315.

Heat

STATE OF VAPOUR SUBSISTING IN THE ATMOSPHERE,

Heat o f
boiling
water.

Bar.

30
29

28

27

26

2.5
94
25

22
21
20
19
18
17
16
15
11

Heat.

212°
210,28

208,52
206,73
204,91
203,06
201,18
199,27
197,33
]95,36
193,36
191,06
188,46
1 85,56
184,36
180,86
176,70

209

The accuracy of this table even in the lower Table of the
part of the fcale is fufficiently apparent by the re- h^Vingvvltsr°at
fult of the experiments of Sauffure on ebullition on different irations

,,_,,„, . of the barometer,

Mount Blanc ; for on that enormous mountain, the from ,0 incfte»
barometer (landing at 16 French inches or 17,05 t0 i4inche8«
Englifh, he found water to boil at the heat of
68°, 993 of Reaumur, a degree which on Geneva
thermometers is equal to 1 85°,56 Englifh. Hence
we fee that diftillation maybe more ad vantageouf-
Iy efFecled on mountains than on plains, and at low
barometrical heights than at the greater, yet w'th-i
in certain limits ; for at heights that furpafs eight
or ten thoufand feet, the fuel, by reafon of the ra-
rity of the air, is more (lowly confumed. Hence
alfofrom the knowledge of the degree of the heat
of ebullition to two or more decimal places, the
(late of the barometer above or below 212° may '
infer to one or more decimal places.— The rea-
fon of this rapid diminution of the heat of ebulli-
tion below 25 inches is evidently the diminution of refiftance,
from the diminiflied weight of the atmofphere, which then is
very fenfible; but as the cold continually produced by evapo-
ration is then alfo very confiderable, the time neceffary to pro-
cure ebullition is longer as SaufiTure remarked on Mount Blanc*
vol. vii. in 8vo. § 2011, p. 328. He found the heat of ebul-
lition barometer 16 to be 68°,993 degrees, or in Englifh mea-
sures barometer 17,05. 185°, 5 of Fahr. (counting one of
Reaumur at Geneva = 2,225 of Fahr.)

Hence (ince, according to Mr. Watt, the fenfible heats of Hence the fpe-

the vapours of boiling water at different barometrical heights £fic heakc,°£-

* & ' . fteam at differ-

are as the barometrical heights reciprocally, and the fpecific ent tempera-
heats of the vapours of water boiling are as the fenfible Heats tures#
reciprocally, it being known, that the fpecific heat of the va-
pour of water heated to 180 degrees above the freezing point
is 940. The fpecific or latent heat of the vapour of boiling
water, whofe fenfible heat is known, (and it may be known by
the barometrical height as fhewn in the above table and the
notes) may alfo be difcovered.

Thus the fenfible heat of the vapour of boiling water ba- Inftance.
rometer 30 being 180° above the freezing point (212° — 32°
= 180°) and the fpecific or latent heat of vapour, whofe fen-

Vol. V.— July. P iible

210 STATE OF VAPOUR SUBSISTING Itf THE ATMOSPHERE.

fible heat is 2Q8°,56 (that is 176,56 above 32°) as it is when
the barometer ftands at 28 inches, is 958 for -£f 176,56. 180
: : 940.958 *.
Untombined As pure invifible vapour does not in ray opinion (of which I

vapour confiaer- nave already ftated the grounds) exift in the atmofphere when
its denfity is higher than 25, as it is in me# of the inhabited
parts of the globe, but is always in this cafe united to air, an
enquiry into its latent heat at different temperatures below ebul-
lition were fuperfluous. But as it does exift in air whofe denfity
is 25 or lefs, fince it is found in air whofe denfity is 12,5, it
becomes neceflary to examine its latent heat in fuch cafes, in
all temperatures inferior to that of ebullition. Now, by ana-
logy, I apprehend, this latent heat in all inferior temperatures
may thus be determined :
Determination of As the fetifible heat of ebullition, when the barometer is at 25

the latent heat of or Deiow 25 is to the latent heat of the vapour at ebullition, fois
pure vapour. r.

the ftnfible heat of water heated to any inferior degree above

32° to the latent heat of its vapour, multiplied by 5,222. Thus
the fenfible heat of water in ebullition barometer 25 being
171°,4 (= 203°,4-32°) its fpecificheat is 987 /=169206j

the latent heat of the vapour of water at 22° above congela-
tion (that is 52 on Fahr. fcale) is 657 for 4r 171°, 4. 987 : :
22°. 126 x 5,22 = 657. The latent heat of vapour in fuch
cafes cannot be determined by experiment on account of the
admixture of atmofpheric air, we mud therefore refort to ana-
logy, which in this cafe is perfect.

The latent heat of pure vapour at greater heights is more
confiderable : thus at heights, at which the barometer ftands at
20 inches, the latent heat of vapour whofe temperature is 22*
above 32°, as in the laft cafe, is 730 ; for the heat of ebulli-
tion is 194°,8, per table, == 162°,8 above 32°; andthelatent
heat of the vapour at ebullition is 1039. Now —• 162,8.
1039 : : 2°. 140 and 140 x 5,22 =730.

As air is cooled by the reception of moifture diflfolved in it,
we muft infer that its capacity for containing heat is increafed,
and hence moift air is more difficultly heated or cooled than dry
air of the fame temperature. (For the cold proceeds from the
abforption and not from theexpulfion of caloric.)

• Hence 169206, being the produft of 180° X940, is the com-
mon dividend of all fenfible heats belowo 180° . when the latent heat
•f the vapour is fought at barometrical heights below 30 inches.

4 The

STATE OF VAPOUR SUBSISTING IN THE ATMOSPHERE.

211

The elasticity or expanfive force of pure vapour has been Elafticity of
examined at every fifth degree of Reaumur above Oto 110°. lectures above
by Mr. Betancourt, and may befeen in an excellent work of freezing.
Prony's, his Architecture Hydraulique, he has by a mod ingeni-
ous calculation interpolated the expanfions anfwering to the in-
termediate degrees. But Mr. Schmidt feems to have deter-
mined this expanfive force ftiltmore exa&ly than Betancourt.
Hence I here infert his table, adding Farenheit' s for Reaumur's
degrees, and diftinguilhing the expanfions interpolated by cal-
culation from thofe actually obferved by /. The forces are mea-
fured by the elevation of a mercurial column in inches and
hundreds of a French inch *.

Reau-

Farenheit.

Expanfive

Reau-

Farenheit.

Expanfive

mur.

force.

mur.

Force.

1

34°,25

,01/

21

79°,25

1,01/

2

36,5

,03/

22

81,5

1,01

3

38,75

,05/

23

83,75

1,19/

4

4-1,

,07 /

24

86,

1,29/

5

43,25 i

,11

25

88,25

1,30

6

45,5

,15

26

90,5

1,38/

7

47,75

,16/

27

92,75

1,42

8

50, '

,20/

28

^ 95,

1,60/

9

52,25

,251

29

97,25

1,80/

10

54,5

,23

30

99,5

1,93

11

56,75

,34/

si'

101,75

1,02/

12

59,

,38

32

104,

1,12/

13

61,25

,44

33

106,25

2,23

14

63,5

,50/

34

108,5

2,40/

15

65,75

,55

35

110,75

2,68

16

68,

,61

36

113,

2,80/

17

70,25

,69/

37

115,25

3,20

18

72,5

,76

38

117,5

19

74,75

,84/

39

119,75

3,40

20

77,

,90

40

122,

3,64

j

80

212,

28,

* The Paris cubic inch =r 1,21 Englifli. Now the Englifli cubic
inch of mercury when its fpecific gravity is 13,6 weights 3443,2'
Engliih grains, therefore the Paris inch weighs 4 1 86 Englifli grains,
and 11^ of this inch — 418,6grs : and T-|T of this inch41,86 grains.

P2

Note.

212 STATE OF VAPOUR SUBSISTING IN THE ATMOSPHERE.

Note. — lft. Moft of the interpolations from the 88th degree
to the 122nd I have myfelf inferted as thofe calculated by-
Schmidt erred too widely by his own account. 4Gren. Phyf.
Journ. 273.

2d. Mr. Piclet has alfo made a fet of curious experiments
on the elafticity of pure vapour in low temperature. Ejfaisdc
jR/ty/tijue, p. 157. He found (hat a grain of warm water in
•vacuo evaporates in forty minutes in the temperature of 38^
Fahr. under a receiver containing 1452 Englifli cubic inches,*
but that it did not diffufe itfelf equally in lefs than fix hours,
and then raifed the hygrometer from 17° to 60° that is 43°,
and during this whole time the cold under the receiver was
conftantly decreasing, though (lowly, which decreafe un-
doubtedly contributed to the diffufion of the vapour.

Mr. Schmidt has alfo made aferies of experiments upon the
dilatibility of air, made as dry as, poffible by expofure to hot tar-
tctfin, an object of great importance, that had never before been
examined. This table I here infert, converting Reaumur's
degrees into thofe of Fahr. and adding from his formula the
degrees he omitted.

' Expanfions of dry Air,

Table of expan-

i

fionsof dry air.

Reau»

Fahr.

Expanfion of

Reau-

Fahr.

Expanfions of one

mur.

one Inch at 3s

j mur.

Inch at 320.

1

1

34°/^

,004467

79°,25

,0938175

36,5

,008935

81,5 '

,0982S50

38,75

,0134025

83,75

,1027525

4

41,

,0178700

24

86,

,1072200

43,25

,0223375

88,25

,11116875

45,5

,0268050

90,5

,1116155

47,75

,0312726

92,75

,1206225

8

50,

,035740

28

95,

,1250909

52,25

,0402075

97,25

,1295557

54,5

,0446750

99,5

,1340250

56,75

,0491425

101,75

,1384925

12

59,

,0536100

32

104,

,1429600

61,25

,0580775

106,25

,147427.5

63,5

,0625450

108,5

,1518950

65,75

,0670125

110,75

,1563625

16

68,

,0714800

36

113,

,1608300

70,25

,0759475

115,25

,1652975

72,5

,0804150

117,5

,1697650

74,75

,0848825

119,75

,1742825

20

.77,

,0893500

40

122,
212,

,1787000
,3574000

* Ibid, page 91,

Nits.

S*ATE OF VAPOUR SUBSISTING IN THE ATMOSPHERJ. 213

Note. — 1. Hence we fee that 1000 inches or meafures of
dry air at 32° would become 1004,4675 at 34,25 Fahr. and
at 50°. would become 1017,87. Hence 1000 meifures of
dry air gain 1,985555, &c. by each degree of Fahr. above 32°
(or morecompendiouily 1,9856 which is true to two decimal
places) or nearly two.

2, We fee the fource of the difcordani refults of D'Amon-
toms, De Luc, Lambert, Schuckburg, Roy, Berthollet, and
Monge, &c. for they all operated upon air more impregnat-
ed with various degrees of moifture; beiides taking the boil-
ing point at different barometrical heights ; in the prefent ex-
periments it was taken at 29,841 Englifli inches.

3. It appears that the expanfions are as the differences of
heat above 32° as D'Amontons, Lambert, and Schuckburg alfo
noticed, though their experiments, not being. made on perfectly
dry air, could not be very exact.

The dilatation of the moifture contained in air has been fe- Dilatations of ait
parately examined by Mr. Schmidt, ami he has fhewn how from fat^at«i with
it the volume of air iaturated with moiluire, laturated I fay at
every degree of Reaumur, may be difcovered ; the refult of
his experiments appear in the following table of the volume
which 1000 meafures at 32° of air would acquire if Jhturated
•with moijlure at each degree of Reaumur above 32° expreffed
on Farenheit's (bale *.

Reau-

Fahr.

Expanfiva

Reau-

Fahr.

Expanfive

mur.

Force.

mur.

Force.

1°

34°,25

1010,56

70,25

1122,68

36,5

1010,78

72,5

1 1 32,25

38,75

1016,45

74,75

1142,53

,41,

1022,21

20

77,

1152,83

5

43,25

1028,58

79,25

1164,02

45,5 .

1034,97

81,5

1175,23

47,75

1040,41

83,75

1186,52

8

50,

1048,52

24

86,

1198,59

52,25

1056,26

25

88,25

1211,44

10

54,5

1064,72

90,5

1223,65

56,75

1071,28

92,75

1279,62

12

59f

1078,52

28

95,

1377,09

61,25

1087,11

97,25

1494,02

63,5

1095,76

3 0

99,5

1610,02

15

65,75 .

1104,46

101,75

1725,49-

l»

68,

1113,21

32

104,

1849,96

33

106,25

1983,42

* To prevent

miftakes, it i

nuft b

e noted ths

t this table is not

meant

214 5TATJC OF VAPOUR SUBSISTING IN THE ATMOSPHERE

Remarks. Note. — 1. Hence we fee that air faturated with moifturp

Air faturated at high heats is much more expanded than dry air of the fame

with moifturc r j ,

expands more temperature, as De Luc and General Roy have alfo obferved.
than dry air. but in temperatures below 36°,5 dry air is more dilatable
which probably induced SaufTure to conclude it was fo at
higher temperatures. At 54,5 the difference is very percep-
tible for J 000 parts dry air at 32° are expanded at 54°,5 that
is by 22°,5 above the freezing point to 1044,67, whereas
1000 parts of air faturated with moifture, are extended to
1064,72 and in higher heats, the differences of expanfion are
incomparably greater.
Moift air more 2. Hence it is plain why moift air, fuch as that of the Weft
u oca mg Indies is much more fuffocating than dry air of the fame tem-

perature. For 1000 cubic inches of air faturated with moif.
ture at 869 of Fahr. contain nearly 76 inches of moifture
which is ufelefs to refpiration.
Gen. Roy's 3. Thefe experiments agree with thofe of general Roy, in

experiments. wnich fleam was introduced at hazard, for the general found
that from 32° to 52° each degree gave at a mean 2,588, and
eonfequently thefe 20° would expand 1000 inches to 1051,76,
and by Schmidt's experiments much more accurately made,
we have 1050,33.
Irr-gularity of 4. Schmidt alfo obferved a peculiarity in the expanfion of
the expansions moift ajr, previoufly noticed by Roy, for Schmidt found that
9 the expanfibility of air, faturated with moifture, was fmaller
than the expanfibility of pure vapour, until the 167th degree
of Fahr. but in higher degrees they confiantly approached
nearer to each other. And the general obferved that the mean
rate of expanfion, which from 152° to 172° of Fahr. was 12
for each degree, did from the 172° to the 192° increafe to
17,88 for each degree, and increaled ftill more after the 192d
to the boiling point. The fluggifhnefs of expanfion of air,
faturated with moifture at about 32°, was alfo noticed by the
general, and he hence concludes the mean rate of expanfion
from 0 to 32° of Fahr. to be 2,27 for each degree, which is
fmaller than that of drier air.

meant to exprefs the dilatations of air faturated at any particular
degree of heat it would acquire at other fuperior degrees, but only
the bulk that 1000 parts dry air at 32° would acquire by faturation
at each higher degree.

Thefe,

STATE OF VAPOUR SUBSISTING IN THE ATMOSPHKRf . 215

Thefe variations of the rates of expanfibilify of moid air, afcribed to dif-
faturated at different temperatures, Schmidt very juftly attri- Je"nact%°ff"^t
bates to the variation of the degrees of affinity or adherence temperatures.
of air and vapour to each other at different temperatures. At
32Q Fahr. it is very ftrong, and alfo below that degree ; and
hence the ftrong folvent power of air, colder than the water
it acts upon, remarked by Richman ; but if both are equally
cold very little moifture will be taken up by the air, as already
mentioned ; and hence I have faid that air diflblves vapour
when this is in a nafcent ftate. But in heats above 167° or
170° air and vapour are difpoied to feparate.

5. Hence we may deduce the impoflibility of difcovering a Hence there

coefficient univerfaliy applicable to exprefs the rate of expan- ca.n be "od<Lter-

_ . . n . . minate coeffi-

uon of air in every ftate of moifture,, (as Tremley has well cient to exprefc

noticed. See 2 Sauflure Voy. aux Alpes 4to). This mud *** ratc*
vary with the mean ftate of hygrometers above and below the
heights to be meafured ; and experiments of this kind have
not yet been made. De Luc's coefficient anfwers tolerably
well for very dry air, that is whofe faturability is greateft, Sir
George Schuckburg's for air much moifter,*and general Roy's
for air ftill more moift, that is whofe faturability is fmalleft.
Hence each fucceeds in certain cafes, and fails in others. The
dilatation or contraction, which air faturated with moifture at
any one given degree of temperature receives without the ad-
dition of any more moifture, at any higher or lower degree of
temperature, has not as yet been difcovered; for Schmidt,
who alone has attempted it, is juftly diffident of the correcl-
nefs of the table he has given of it, and in fact it is not
grounded on the indication of any known hygrometer, and
improperly fuppofes the L. degree to indicate the mean be-
twixt the loweft and faturation. Whereas the LXVth degree
on Sauffure's indicates that mean; and XCVIIL and not C.
indicates faturation.

According to Mr. Watt (as ftated by De Luc, 3 Meteor o- Specific gravities
log : p. 14-5) the fpecific gravity of pure vapour is to that of °f vapour and *
air as 4- to 9. I fuppofe he compares it with air at the ufual
denfity of 30 or 29, and at fome particular temperature which
is not mentioned ; for at high temperatures the difference muft
be much greater, as appears by the foregoing tables.

(To be concluded in our next.)

210 NOTICES CONCERNING PHILOSOPHICAL APPARATUS.

t

XIII.

Notices concerning fome Philofophical Apparatus. — Electrical Bat-
tery of Talc. — Complex Ilorfejhoe Magnet. — Mr. Davy's
apparatus, fyc.

Battery of talc. SEVERAL years ago (in 1788), when I was bufied in elec-
trical refearches, I was induced to conftruct a battery of talc,
in confequence of the very great capacity of that fubftance
which I found (conformably to the determination of Mr. Ca-
vendifli with glafs), to be inverfely as its thicknefs. As our
galvanic refearches now feem to give additional intereft to ap-
paratus of great capacity and low intenfity, I have thought it
might be acceptable to give a fketch of it.
Jfftimate of the The full charge of two fquare inches of talc gives a fhock
elcclnca! capa- fufficiently fevere to be felt above the elbows, giving a fpark
is as the thick- of above one tenth of an inch long, and requiring the friction
nefs inverfely j 0f more than one foot of glafs to charge it. I compared thif
that'ofgTafs?3 ta*c w'tn a 'arSe jar °f 351 fquare inches, and 0.082 inch
thick, and the talc was 0.01 125 inch thick. The communi-
cation from plus to minus was made by one tingle wire, and
Lane's electrometer was fet fo that the talc exploded regularly
at each turn of a feven inch cylinder. The jar was then placed
in the circuit, and exploded at twenty-one turns. Their ab-
folute capacities were therefore as 1 to 21. But the furfaces
are as 1 to 175, whence the capacities of equal furfaces were
as 1 to yrs, or about 1 to 8. And the thicknefles are in-
verfely 1 1 and 82, whence it appears that the, actual capacities
proved rather in favour of the talc, if* taken from the inverted
ratio of the thicknefs. This, however, may be only ap-
parent, becaufe the talc was more rapidly charged, and had
an infulated rim of only 0.4 inch, whereas the glafs had a bare
rim of 4.0 inches, in addition to which it may be obferved,
that the uncertainty of the refult is not quoted, than the un-
avoidable errors from the admeafurements of the thickneffes
and the unfteadinefs of excitation.
Drawing and Plate XI. Fig. 1 . reprefents a battery compofed of 12 pieces

defcription or* a ^f talc, each meafuring 2.6 inches in the fide, and coated on
inche! fquare^0 a ^ur^ace °* tvv0 %iare inches. The thicknefs of each piece
and equivalent to was 0.0025 inch, and consequently its capacity may be taken
ofglaft uarefeetat about 20 times that of thin window glafs of one-twentieth.
2 of

KOTICES CONCERNING PHILOSOPHICAL APPARATUS. 217

of an inch thick. The whole furface was 4S fquare inches,
which multiplied by 20, anfwers to 960 fquare inches of glafs
in capacity, or almoft feven fquare feet. It is nece(fary that
a card fhould be placed between each plate of talc and its
neighbour, and hence by an eafy computation, it is found that
the talcs and cards (of T% of an inch thick), requifite to an-
fwer to 100 feet of glafs would be about 3f inches thick. .

This instrument for the purpofes of low intenfities would be size of a battery
incomparably cheaper and more manageable than glafs. In- equivalent tq

ill /• • n r i r 7- i i 20>°00 fquare

deed a battery anlwenng to twenty thouland lquare feet would feet#
be very portable, and might be put into a box of one foot
fquare and two feet deep. But it mull be remembered that
the intenfity cannot be greater than to give an explofive fpark
of one thirteenth of an inch, or lefs, and confequently that
this apparatus is limited to experiments requiring no greater
intenfity.

The conftruc~tion is that defcribed by Beccaria, in his arti- Beccaria's
ficial electricity. Fig. 2. reprefents the arrangement of the attery*
plates of talc with fquare coatings of tinfoil between them.
From each coating alternately fucceeds a tail, fo that all the
pofitive fides unite above, and all the negative below. » In • • *

Fig. 1. the wire c. communicates with all the coatings of one
kind, and the wire a in like manner unites all the coatings
from the oppofite fides j and at b is an infulated fcrew wire
forming the electrometer of Lane. The pillar fupporting the
fcrew e may either be of glafs or other infulating matter, or
elfe a piece of amber, d may be placed between the battery
and e. In my apparatus, the talcs were confined between two
fquares of glafs, and on the outfide of thefe were two fmaller
pieces of wood as in the figure.

I did not make many experiments with this battery, becaufe
the fpontaneous explofions of one plate ufuaily broke all the
reft, and it was my intention to have them fomewhat thicker,
and to have interpofed cards between plate and plate. But
other purfuits have hitherto prevented my refuming this object.

Complex Ilorfefhoe Magnet.

Fig. 3. in ihe fame Plate XI. was given me by the late Complex horfe-
George Adams of Fleet Street. It was wrapped in a paper on ftoe maSnet»
which the workman who made it had written the following
Wprds.

" The

21$ NOTICES CONCERNING PHILOSOPHICAL APPARATUS

" The outfide bit taken off, but drops when the infide one

flicks, but drops when the outfide one is put on. Apply the

magnet as directed, the ftrokes to be north to north ftrait acrofs

the infide, very difficult to gain, but may be otherwife varied

at pleafure."

has four poles When I firft had it, the middle piece would not drop off

and fcur neutral when tjie outer was put but on the contrary, the outer

points, which r . , " .

•re changed in was difengaged by application of the inner piece, and this is

their power by the cafe at prefent. I could not obtain any explanation of the
obfcure writing I have copied. The fketch fhows where the
poles were at firft and ftill are placed, being four in number,
fo that it feems to be two horfeflioe magnets joined by a fhort
bar nearly ftrait. It barely held its own weight by the outer
piece, and much lefs by the inner ; but now, whether by the
courfe of time in which it has been carelefsly thrown in a
drawer among other metallic matters for fixteen years, or whe-
ther from any other caufe, its attraction is frrongeft at the inner
extremities though not fufficient to bear its weight.

Galvanic Apparatus.
Davy's apparatus Plate X. Fig. 2 and 3. reprefents the apparatus of Mr. Davy

^ffi/1 for takin§ the galvanic fPark in the gal*es *•

Fig. 1 . reprefents the apparatus for taking the fpark. A is
a tube graduated to grain meafures. C is a platina wire her-
metically fealed into the tube and having a piece of charcoal
attached to its top. B is a moveable platina wire, having
charcoal at the top ; the effect is produced by making the con-
tact between the piece of charcoal. In cafes where the fluids
are very imperfect conductors, the wires may be ufed without
the charcoal.

Fig. 2. reprefents the apparatus for taking the fpark in gafes,
it is ufed over mercury. A and B are the communicating pla-
tina wires to which the charcoal is fattened, and C is the gra-
duated tube in which the gas is acted upon.

* Royal Inftitution, I. 214.

XIV. Experiment

EXPERIMENT ON CANDLE LIGHT. 219

XIV,

Experiment to determine the relative Quantities of Light afforded
by Candles of different Dimenfions, in a Letter from a Cor-
respondent.

To Mr. NICHOLSON.
SIR,

A HOUGH your ingenious correfpondent Mr. Ezekiel Prefatory re-
Walker, aflerts with confiderable decifion, that the light af- ?*«J£5,n
forded by candles, is proportioned to the quantity of material perimentsoa
con fumed, yet as he has not given the detail of his experi- light, &c»
ments, but feemsin fome meafure to have deduced thisrefult
by argument, from the fuppofed nature of the fubjecl ; and
as the quantity of light does undoubtedly follow a very dif-
ferent ratio in candles which require muffing, accordingly as
that operation is either performed or neglected. I think it
very detirable, that a courfe of experiments (hould be infti-
tuted for the purpofe of affording the refults you have your-
felf enumerated in your annotation upon one of that gentle-
man's papers. In the mean time, I prefent you with a tingle
experiment upon his two wax candles, which were taken by
me in preference, becaufe they require no fnuffing.

One of thefe candles was a taper of iixteen to the pound, Experiment with
and meafured in length twelve inches; the other was a^j^^
thicker candle of fix to the pound, and nine inches long. It candle.
is not neceflary to ftate the diameters, becaufe they are not
required in the prefent eftimate, and might if neceflary, be
deduced with greater precilion from the weight and length,
than from actual admeafurement ; and with regard to the
wicks, I have only to remark, that they were well adapted to
the candles — though it was impoffible for me to afcertain their
weight or finenefs in the manufactured ftate.

Thefe two candles were lighted at the fame time, and when
tfiey were in the ftate of full and perfect combuftion, their
lengths were refpe&ively meafured and noted down. The
intenfities of their lights, were compared by the method of
fhadows. The diftance between the two candles was twenty-
four inches; and when the fhadows were of equal intenfity,
the diftance of thefcreen from the neareft candle was ieventy-

two

220 EXPERIMENT ON CANDLE LIGHT.

Experiment with I wo inches. The fhadow into which the large candle threw
V.hJ" and a its light, was evidently ruddy or brownilh, while the other
cmdle. fhadow illuminated by the fmall flame, feemed to have a

blutfh tinge. The flames themfelves appeared to differ in their
afpect; in the Tame manner as their fhadows : now the lights
emitted being inverfely as the fquare of the diftances, will be
as 36 to 64, or as 9 to 16 ; and when both were extinguished,
it was found that three inches of the large candle had been
burned, and 5.8 inches of the fmaller : but of the larger
candle, fifty-four inches in length make one pound, and of the
fmaller 192 inches make the pound; and if we divide 54
inches by three, the quotient will be 1 8, which (hews, that
the whole pound of large candles would have required
eighteen times our period for its confumption : in like manner,
by dividing 192 by 5.8, we have a quotient of 33.1, or the
time of burning a pound of the fmall candles. And laftly, if
we multiply the quantity of light afforded by each candle, by
the time required to confume a pound of each, we fhallhave
the proportionate quantities of light afforded by equal expen-
ditures of the combuftible, that is to fay, 18 multiplied by 16,
produce 28S, or the light afforded by the larger candle, and
33.1 multiplied by 9, gives 297.9 for the fmaller: which is
one part in 29 in favour of the fmall candle.

I confider this difference as a greater quantity than the
errors of experiment, though upon the whole, it feems to con-
firm Mr. Walker's doctrine.

Reft
tailed

SCIENTIFIC NEWS.
On the Nutriment to be obiained from Bones,

efuks asde- J[N" the firfl volume of the octavo feries of this Journal, page
jed j rouft. I0Q^ notjce n taken of the experiments on this fubject, detail-
ed by profefifor Prouft of Madrid, in his inquiry into the
means of improving the fubfiftence of the foldier. He ilates
the quantity of jelly obtained from bones to be very variable,
according to the. nature of thofe employed, viz. from nine
pints to thirteen quarts, from five pounds of bones; thofe from
the rump and fpine yielding the moll and befl ; and thofe of
the legs and thighs the leaf! and molt unpalatable. i

Sine

-SCIENTIFIC NEW«. 221

Since his work a memoir on the gelatine of bones has been By Cadet dc
publiflied at Paris by Cadet de Vaux, extracts from which Vaux*
have been circulated through France by order of the minifter
of the interior, in which this method of making a wholefome
■and pleafant food is ftrongly recommended. His experiments
are faid to have afforded remits nearly fimilar to thofe of
Prouft, but on being repeated by Dr. Young feem to have
completely failed* His experiment which is inferted in the
fifteenth number of the Journals of the Royal Inftitution, is
as follows:

Three quarters of a pound of bones were taken from a Dr* Young**
piece of beef which had been roafted; they were principally expen
the vertebral and fpinal proceffes; they were reduced to a
fmooth pafte, by pounding them for twenty minutes, with
a little water, in a large mortar. They were kept on the
fire in an earthern pipkin, fimmering or flowly boiling, for
forty hours, with the addition of proper vegetables, fo as to
make a quart of broth. The broth (hewed no tendency to
jelly when cold ; it tafted only of the vegetables, and had
neither the appearance, nor the flavour of a highly nutricious
fubftance : there was nothing difagreeable in it except its in-
iipidity, but a few ounces of meat would probably have made
a better foup.

Method of preparing Muriatic Ether withfimple Acid; by munat^c'ecber
M. Boss a, Apothecary at Hameln*. by Bajfe.

MELT marine fait in a crucible and keep it in fufion an
hour, or til! the whole of the water of cryftalization is dif-
iipated. Put twenty ounces of this fait into a tubulated retort.,
adapt a curved tube to it, and plunge the tube to the bottom
of a bottle with two necks, into which have been poured ten
ounces of alcohol, marking 100 on Richter's alcoholimeter.
(This alcohol muft be prepared by mixing three parts of highly
rectified fpirit of wine with one part of potafh, melted and
pulverized whilfr. hot, and diftilling it in a retort till it be
diminifhed one half.) When the whole is well luted, pour
into the retort, in quantities of half a penny weight at a time,

* From Scherer's Journal de Chemie.

ten

222

SCIENTIFIC NEWS.

ten ounces of highly concentrated fulphuric acid. After each
introduction of acid, clofe the tubulure carefully, and put in
no more frelh acid till the fait has quite ceafed bubbling.
The cork of the other neck of the bottle muft be taken out
from time to time, to fuffer the air condenfed above the al-
cohol to efcape.

After all the acid is introduced, place the retort on a fand-
bath, and heat it gradually till all the muriatic acid be ex-
pelled. During this part of the operation, care muft be taken
frequently to cool the bottle containing the alcohol, by wrap-
ping a wet cloth round it.

The alcohol, thus charged with acid, is then put into a re-
tort and diftilled to one half. Shake the diftilled liquor with
a fufficient quantity of alcaline ley to carry off the acid, de-
cant the fupernatant portion, which is ether, and keep it in
bottles well corked. From the above mentioned quantities,
two ounces and a half of ether are ufually obtained.

M. Bofla aflerts, that by operating with thermoxy dated
muriatic acid, light alcoholic ether can never be obtained,
but only a heavy oleaginous ether, which, inftead of floating
on water, falls to the bottom of that liquid.

On the Effecls produced by the Decortication of Trees.

Decortication SEVERAL papers have lately appeared in the American

Philofophical Tranfa&ions, and other fcientific works, re-
commending the depriving trees of their bark as a means of
exterminating noxious infects which find fhelter in the crevices
of the bark, and between it and the body of the tree. From
the effects produced on two apple-trees, as related in the
Monthly Magazine for laft month, though the fource from
which their information is derived does not appear, it would
feem that this practice is deftructive of the tree itfelf. The
relator aflerts, that, one of the trees died in May following
the operation, and the other before the neighbouring trees
had ihed their leaves. He alfo ftates that the denuded trees
were affected by feveral long fiflures, which he attributes to
the alterations of heat and cold, and confiders as the im-
mediate caufe of their death. He concludes by a query,

whether

ACCOUNT OF NEW BOOKS. <£23

Whether (heltering the trunks by matting, or other effectual
means might caufe the fuccefs of the fcheme, and recommends
the experiment.

The fociety of agriculture/ commerce, fciences and arts
at Chalons, in the department of the Marne, have repro*
pofed the following prize queftion, to which no fatisfactory an-
iwer was received laft year.

" What defcription of ufeful plants of any fpecies, can Prize queftioa

be made to grow on the moft barren foils, fuch as thofe of the *]*nts f°r

° barren foils*

ancient Champagne (or department of the Marne) which

prefents little or no vegetable earth, above a chalky or fandy

tufa ?"

In confequence of the importance of the queftion, the .

fociety have increafed the value of the gold medal, from 1000

to 1500 grammes of (ilver, or 300 livres ; it is to be decreed

at the public fitting of the Society, on the 1ft of Vendemiaire

in the 12th year.

ACCOUNT OF NEW BOOKS.

Refearches into the Properties of Spring Water with Medical Lambe on fpring
Cautions (illujlrated by Cafes) againji the Ufe of Lead in the water*
Conjlruclion of Pumps, Water Pipes, Cijierns, fyc. By
William Lambe, M. D. late Fellow of St. John 's College
Cambridge, pp. 204. London, 1803.

JL HE object of this work is an inveftigation of the qualities
accidentally acquired by water, which render it in many in-
fiances injurious to health. Of thefe, lead is a principal
caufe, which in whatever form it is introduced into the human
body, is equally deleterious and fatal. In treating of this
poifonous metal as a receptacle or conductor of water, he
fliows how it is acted on by it and air, fo as to be capable of
fufpenfion in the fluid, by which means it is received into the
alimentary canals, and conveyed to every part of thefyftem.
Hence arife difeafes, which from their caufe being unfuf-
pected, and confequently fuffered to continue its effects, are
unconquerable by medical ikill. Many inftances of this de-
fcription are given, fome of which were removed by change
of refidence, and recurred on the return of the patient, nor

were

£0 -£ ACCOUNT OF NEW BOOKS.

were they effectually fobdued, until the difcovery of the
caufe, and the discontinuance of the ufe of the water which
produced them.

Mr. Lambe has (hewn a perfeverfng attention to the fubjeft
he has undertaken to invefligate, and has very clearly proved
•the .noxious effects arifing from the unguarded ufe of lead in
domeftic economy.

Sheldrake on Ufeful Hints to thofe ivho are afflicted with Ruptures, on the Na-
ruptures. - ture, Cure, and Confequeiices of the Difeafe ; and on the Em-

pirical Practices of the prefent Day. By T. Shel dr AK£,
{ Trufs-Maker to thcWepninfter-Hofpital, pp. 180. London,

1803.

A

JOURNAL

OF

NATURAL PHILOSOPHY, CHEMISTRY,

AND

THE ARTS.

AUGUST, 1803.

ARTICLE I.

On the Production of Sulphate of Magnefiafrom the AJhes of Pit-
Coal, with Remarks on the Effiorefcence of the fame Salt, ob-
ferved by Dr. Boftock. In a Letter from the Rev, William
Gregor.

To Mr. NICHOLSON.
SIR,

IN the number of your Philofophical Journal for December, "Effiorefcence

1802*, I read a letter from Dr. Boftock of Liverpool, infr"m a??es °/u
' . r p:t coal, which

which he gives an account of an unexpected production of the afforded gypfurn
fulphateof magnefia; which brought to my recollection a facl, and fujPha<£ ofJ
which fell under my notice, about two years ago, and which •
may poffibly tend to throw fome light upon the phenomenon
obferved by your correspondent. — Having accidentally dis-
covered a faline cruft adhering to the wood-work of a frame on
which I fift my coal-afhes, for economical and agricultural pur-
pofes, I fcraped off a fufficient quantity of this fubftance with
a view of afcertaining its nature. I diflfolved it in diftilled
water, and Separated all impurities from it, by the filter. This
folution tried by the ufual tefts, gave indications of the prefence
of fulphuric acid, of lime, and of ibme other earth. I evapo-
rated the folution, and fome gypfum wras Separated ; when this
fait ceafed to appear I poured off the fluid, which had affumed

* Vol. HI. p. 288.
Vol.V. — August. Q a brownifh

22(J SULPHATE OF MAGNESIA.

abrownifh hue. I gradually evaporated itftill further, and (et
it afide in a cool place: It (hot into a beautifully cry ftallized
fait, which agreed in form and properties with U)e pureft ful-
phate of magnefia, except as to colour, which inclined to-
wards a brownifh tint, which circumftance probably arofe from
the extractive matter of the decayed wood, which this fait had
penetrated. The coals, which had been lifted in this place,
were thofe from Liverpool and Wales. The place was open
to the air and rain.
Liverpool coal I" order to narrow my field of conjecture as to the origin of
treated more tjie above-mentioned falts, and to exclude, as far as pofiible,
a^purer refult. " tne concurrence of unknown circumftance?, I collected a fuf-
ficient quantity of allies from my own fire in my ftudy, where
I had burnt Liverpool coals only. On repeating the fame pro-
cefs, the refult was the fame : I obtained gypfum and a ftill
purer fulphate of magnefia : The quantity of the latter ex-
Welch coal alfo. ceeded that of the former. I examined alfo the allies pro-
duced by Welch coal, and I detected gypfum and the fulphate
of magnefia in them alfo. They contained, however, a much
larger quantity of gypfum than of the latter fait.

The exact quantities of thefe falts, which might be obtain-
ed from a given weight of the allies of thefe different coals,
I did not a/certain.
Thefe aflies The aflies obtained from the above-mentioned coals were

were a good ™- from t;me ^0 tjme fpread, (or to ufe our common and provin-
cial term) Jkeaded * over grafs, and with apparently good ef-
fects, notwithftanding the fulphate of magnefia, which, I wa»
well affured that they contained.
Mr. Tennant Mr. Tennant's difcovery of the unfriendly nature of magnefia

LfiasHid iti *° vegetati°n IS to De ranked amongft the few prominent and
carbonate are in- well eftablilhed facls in agriculture, which modern fagacity
lmical to vege- ^as broUght to light. Communications of fads and difcoveries

tation* but the . .... . . . r • • i , r

fulphate may in this highly important tcience are, indeed, abundantly lup-
be good. plied unto us by ingenious and experienced agricultures, but

the truth and the utility of the greater number of them mull,
from the nature of the fubjeel, depend upon fuch a variety of
variable circumftances, that the application of them to parti-
cular cafes can be only contidered as a matter of experiment.
But Mr. Tennant's obfervations, contained in his effay on the

* Etymologifts may probably recognize in this word the Greek
verb Zk@ccv,
5 different

SULPHATE OF MAGNEStA. 227

different forts of lime ufed in agriculture, feem to ftand, in a
great meafure, independent of local dnd contingent circum-
ftances, afid may be fafely recorded amonwft the certainties of
the fcience. But in this, as in other fubjccls wemuft be care-
ful, that our conclusions do not wander beyond the limits which
our premifes warrant. Magnefia and carbonate of magnefia
may be inimical to vegetation : But it by no means follows from
the admiffion of this fact, that magnefia combined with ful-
phuric acid pofleffes the fame dehVuclive properties.

I conjectured that the origin of thefe falts in coal afhes Was Origin of thefe
to be alcribed to the decomposition of fchiftus and pyrites, up ates*
both which fubftances are frequently found amongft pit coal.

In order to form a judgment refpecling the probability of Pyrites and /lea-
rn y conjecture, I mixed fome pounded pyrites with ionie IJ" 'gnKe^ and

„ J . J , / lJ r . then expofed to

iteatite reduced to powder in the proportion of about 2 : 1 the atmofphere
and expofed this mixture in a crucible for about an hour and a aff°rded fulphate
half to the heat of a brifk fire in a common grate. There
remained at the bottom of the crucible a dark red powder,
which was expofed to the air for a considerable time before I
examined it. — I threw it upon a fiitre and poured diftilled
water upon it, which tafted exceedingly bitter, and on fur-
ther examination, I found it to contain fulphate of magnefia.
Pruffiate of potafli did not betray the leaft trace of iron held in
folution. Whether the magnefian fait was in a ftate of ful-
phite at firft I cannot tell.

In places where fteatite and pyrites are plentiful, this procefs This artificial
for obtaining fulphate of magnefia would be neither difficult ^^JJiZ?
nor expenfive.-*In the cafe which Dr. Bollock records, might fitable.
there not have been fome coal afhes mixed with the clay ufed
for making the brick, on which he difcovered the faline efflo-
refcence ?

As I have never feen the foregoing facts noticed by any per*
fon, I have been induced to tranfmit an account of them to
you. If you think them worthy to be recorded, they are at
your fervice.

I am,
SIR,

Your obedient humble fervant,

WILLIAM GREGOR.
Creed, near Grampound, Cornwall,
July 6th, 1803.

Q2 II. The

228 0P MAKING ARTIFICIAL YEAST.

II.

The Method nf making Artificial Yeajl in Germany artdSiueden*.
Communicated by Sir A. N. Edelcrantz.

A'f-ficV >eaft. J[ q one hundred pounds of the bed malt, confining of one

One hundred r "

p.^nis »r malt Parl °f malted wheat and two parts of malted barley, dried in
is brewed wi:h the 0pen ajr anj wen ground or bruifed; add ten pounds of

h-^ps nearly in , , , . . . . , , , , , i rr

the common good hops, and brew the mixture with three hundred and fifty

way;— evapo- pounds of water to form wort, in the common way. After a

fermented VitiT mort bmh'rjg you feparate the grains and hops from the wort,

yea;t; — and which laft by continued boiling may be reduced to the half

agitated with or Qne hundred and feventy-five pounds. Cool it down as

nrty or more J r

pounds of meal, foon as poffible to 70° fahrenht. and mix it then with thirty-two

pounds of good yeafr, which this firft time may be common
brewers yeafl:, but in every fubfequent operation of the arti-
ficial. The wort will very foon ferment, and after four or
five hours it will be covered with a thick, white, yeafly froth.
When this appears, the whole mafs muff, be flrongly agitated,
and at the fame time mix it well with from fifty to feventy-five
pounds of fine ground meal of wheat or barley, either malted
or un malted. By keeping itconftantly in a cool place, it will
continue in a good ftate for ten or fifteen days in fummer, and
in winter from four to fix weeks, and flill longer if ftirred once
or twice daily. This yeaft, when employed in diftilleries,
breweries, or for making cider and vinegar, as alfo by bakers
and paflry-cooks, is aflerted to be as ufeful and effectual as the
beft common yeaft.

III.

Remarkable Facl of the Difappearance of a Mixture of Oxigen and
Hydrogen, at the common Temperature over Water ; inducing
ike Probability that Water may be formed at low Heats. In a
Letter from Mr. B. Hooke.

To Mr. NICHOLSON.
S I R,

1 F you think, the following facl which occurred to me in the
fummer of 1800 (and which feems rather to prove the forma-

* This,procefs was communicated to me by my learned friend, the
celebrated chemift, Mr. Weftrumb in Hamelm* and differs very
little, though more perfect, from the. method ufed in Sweden.

4 tion

EXPERIMENTS OF GASES ABSORBED BY WATER. 229

lion of water from its elements at common temperatures)
worthy a place in your very interefting Journal, the infertion
will oblige, Sir,

your's, &c.

B. HOOKE.
Fleet Street, July 12, 1803.

HAVING been accuftomed to keep (for the purpofe ofoxigenand

deflagrating) a mixture of oxigen and hidrogen gales in the h,dr°§e» mixed
• , , , , r . ../• , and confined in

proportion as nearly as I could guels that would form water, 1 an jnverted

was much lurprifed upon inverting a quart bottle of fuch a bot !e with a
..'*. i a ,° . . . ,. . , .r little water «Hf.

mixture in a pneumatic tub, to find the water immediately rile ed during

up and fill it; as I could only account for it by fuppofing water three months
had been formed from its conftituent parts, or that the gafes **^ va*
had efcaped from the bottle and left a vacuum. Either fup-
pofition appears to be attended with considerable difficulties;
for what nice pay of the affinities could occafion the abftrac-
tion of that portion of caloric which is eflential to the aeri-
form irate of the gafes, and mult be before water could poffi-
bly be formed ; and on the other hand, if the gafes had made
their efcape at the cork, what prevented the atmofpherical
air from entering ? The bottle containing the gafes had been
left inverted in a common bottle rack with a fmall quantity of
water in its neck for about three months.

IV. -,

Experiments on the Quantity of Gafes abforbed by Water, at dif-
ferent Temperatures, and under different Prejfures,. By Mr.
William Henry *.

T

HOUGH the folubility of an individual gas in water forms, Solubility of
generally, a part of its chemical hiftory, yet this property has Saflfs 5n w.at®r
been overlooked, in the examination of feveral fpecies of the examined,
clafs of aeriform fubftances. The carbonic acid, indeed, is
the only gas whofe relation to water has been an object of
much attention ; and, at a very early period of its h ftory, Mr.
Cavendifh, in the courfe of inquiries, the refults of which were except with
the groundwork of the moft important fubfequent difcoveries, j^rc g°Jar"
afcertained, with peculiar care, the proportion of carbonic acid

# From the Philofophical Tranfatfions for 1803.

gas

230 EXPERIMENTS OF GASES ABSORBED BY WATER

gas condenfible in water, at the temperature of 55° of Fahren-
heit. Dr. Prieftley aifo, about the fame period, directed hi$
attention to the faturation of water with fixed air, and con-
trived a fimple and effectual mode of obtaining this impregna-
tion. His apparatus, afterwards, gave way to the more ma-
nageable one of Dr. Nootb ; and this, in its turn, has been
(uperfeded by the improved mode of condenfing, into water^
many times its bulk of various gafes, invented and pra6tife4
by (everal chemical artills, (as well as by myfelf,) both in this
country and abroad.
Preflure. The influence of prefiure, in accomplifhing this ftrong im-

pregnation, was firft, I believe, fuggefted by Dr. Pneftley.
" In an exhaufted receiver/* that mod ingenious philofopher
pbferves, " Pyrmont water will actually boil, by the copious
difcharge of its air ; and I do not doubt, therefore, that
by means of a condenfing engine, water might be much more
highly impregnated with the virtues of the Pyrmont fpring *."

Before defcribing my experiments on the effects of addi-
tional preflTure, in faturatiug water with gafes, it will be ne-
ceflary to ftate the refults of others, that were previoufly ex-
pedient, to determine the quantity of each gas combinable
with water, at a given temperature, and under the ordinary
weight of the almofpbere. In a few instances, alfo, it was
deemed proper to afcertain the influence of different tempe-
ratures, over the condenfation of gafes in water.

SECTION I.

ON THE QUANTITY OF GASES ABSORBED BY WATER,
' . UNDEK THE USUAL PRESSURE OF THE ATMOSPHERE.

A pautus for ?n order to attain confulerable minutenefs in obferving the
fhewing the proportion of gafes ablot bed by water, an apparatus was em-
P^r°br^ofgas ployed, of which the following is a defcription.
water. The veflTel A (Plate J. Fig. 1.) is of glafs, about 2 inches

diameter, and 4-| inches long. Jt is graduated into cubical
inches, and quarter inches ; and furniflied at the top with a
brafs cap, into which a cock a js fcrewed. To the lower aper-
ture, a copper tube C is cemented, which is bent at a right
angle, the leg neareft the veflel being carried downwards, and

* Experiments on Air, arranged and methodized, Vol. J. p. 51,

furniflied

EXPERIMENTS OF GASES ABSORBED BY WATER.* 231

furnifhed with a cock b. B is a glafs tube, of about \ inch
bore, bent at a right angle, and graduated, from a given point,
into hundredth parts of a cubical inch. It is attached to the
copper pipe, by a tube of Indian rubber D, over which is a
covering of leather, forming a joint, which admits of the veflel
A being brilkly agitated. When the apparatus is ufed, it is
firft filled with quickfilver; a transfer bottle of elaftic gum,
furnifhed with a cock, and containing water of a known tem-
perature, is fcrewed on ; and a communication is opened,
through the cocks, between the bottle and the glafs veflel.
The lower cock b is then opened, through which the mercury
runs out, while its place is fupplied by a quantity of water
from above, meafurable by the fcale on A. This transfer is
removed, and another containing gas being fubftituted, a mea-
fured quantity of gas is admitted in a fimilar manner. Strong
agitation is now applied, by means of the joint D ; and mer-
cury is poured into the tube B, to fupply the defcent occa-
fioned by the abforption in A j its level being exactly pre-
ferved in both legs of the fyphon, both at the commencement
and clofe of the experiment. The quantity of mercury re-
quired for this purpofe, indicates precifely the amount of the
gas abforbed.

The only advantage of this apparatus over a cylindrical jar,
inverted in the ufual way over mercury, is, that by means of
the tube B, very minute degrees of abforption may be mea-
fured, which would fcarcely be perceived in a wide veflel.

For the more abforbable gafes, I found this inflrument to Another appa-r
anfwer perfectly well, but, for afcertaining the folubility of J*™ L^^-*
thofe which are taken up by water in only fmall proportion, I forbed by wat«r.
preferred one of different conftru&ion. It confifted fimply of
a glafs veflel, of the capacity of 57 \ cubical inches, and fliaped
as in Fig. 2. At a was cemented a cock, provided with a
fcrew ; and the lower cock b was of glafs, accurately ground
in. The veflel was then filled with water which had been
long boiled ; a lifting valve was fcrewed on a, the cock being
open, and the veflel was placed under the receiver of an air
pump, where it was kept for fome time, the pump being oc-
cafionaily worked, as long as any air bubbles could be feen to
arife. The gas under examination was next admitted from an
elaftic bottle, the cock b being opened, and a meat'ured quan-
tity of water let out. The gas and water were then violently

agitated

232 EXPERIMENTS OF GASES ABSORBED BY WATER.

agitated together; and the cock b opened under mercury,
which afcended into the veflel. The agitation was ftill conti-
nued, obferving to preferve the fame level of* mercury without
as within the veflel ; and, when it rofe no higher, the afcent
was noted by means of the graduated fcale. The quantity of
mercury that had entered the veflel, indicated the amount of
abforption that had enfued.
Another appa- § It might, however, be objected, that the water would ac-
fimp! y aCglafs clt"re a'r aga'n» while poured into the veflel ; and I therefore
globe with a fometimes ufed large glafs globes, having long necks, accu?
long neck. ratejy graduated. Thefe globes, being of very thin glafs,

were filled with boiling water, and inverted inftantly in a trough
of quickfilver. When the water became cold, the mercury
was, of courfe, found to have rifen partly into the veflel. This
portion was difplaced by a meafured quantity of gas; and the
abforption was denoted by the afcent of the mercury in the
graduated neck.
General proceed- The water employed in thefe experiments was boiled, during
lions!" C3U" fecial hours, in a tin veflel having an aperture barely fufficient
to allow the egrefs of the fleam, and poured, while boiling hot,
into glafs veflels, which were corked, and tightly tied over
with bladder. An equable temperature was produced in the
water, mercury, and gas, except when above 85°, by regu-
lating that of the room in which the experiments were made;
and the glafs veflel, during agitation, was carefully guarded
from the warmth of the hand. The agitation was continued,
till it appeared, by the fcale, to produce no further effect ;
and, in the abforption of difficultly condenfible gafes, was re-
peated at intervals, during a«fpace of from twelve to twenty-
four hours. Alterations of the barometer were always ob-
ferved ; and the refiduary gas meafured, or eflimated, at a
preflure of 29 £ inches.

I . Abforption of Carbonic Acid Gas by Water.

Carbonic acid That the temperature of water influences the proportion of

gas lefs abforb- caibonicacid which it is capable of abforbing, is already known

h'gher tempe- as a general fa£t ; * but the exacl amount of this influence has

raturcs. not, I believe, been hitherto afcertained. In the courfe of a

* See Mr. CavendifiYs experiments in the Phil. Tranf. Vol.
LVI. p. 163; and Fourcroy's tyjfeme, 4to. Tom. I. p. 215.

feries

EXPERIMENTS OF GASES ABSORBED BY WATER. C233

feries of experiments to determine it with precifion, I was

furprifed by obtaining remits which difTerecl conliderably from

each other, at the fame temperature of the gas and water ;

when boih were, in different experiments, of like purity; and

when the barometer had the fame elevation. Of the caufe of The refults at

thefe variations I was not aware, till my friend Mr. Dalton l!kt temPera"

../.../....■, tures and pref-

fnggefted, that they probably depended on the variable amount fures are not
of the reiidues • and, on repeating the experiments, with dif- conftant, unlefs
,. . , , , , • r llke quantities

ierent proportions between the gas and the water, this lug- 0f g a be pre-
geftion was fully confirmed. Thus, when two meafures offentC(1>
carbonic acid gas were agitated with one meafure of water,
the abforption was confidei ably greater than when, to the fame
quantity of water, a lefs proportion of gas was ufed. The becaufe the
caufe of this diminimed abforption, feems to be connected fmf!,er refidues

... ... . .... w'il contain a

with the proportion or common air contained in the unab- greater prcpor-

forbed refiduum ; for, betides the unavoidable contamination tion of common

c .% i.-i • > .1 ; • * +t air which retains

ot the gas employed, with a minute portion or the air ot the gas aiong with it.

vefTel ufed for its extrication, a fmall quantity will always be
liberated from the water, whatever pains have been taken to
deprive it of air, by previous long boiling, expofure under the
air pump, or both in fucceffion. That this is the true expla-
nation, appears alfo, from the refult of adding to the gas a
proportion of common air. Thus, when, at the temperature
of 55°, 20 meafures of carbonic acid are agitated with 10 of
water, at leaft 10 meafures of gas are taken up ; but, from a
mixture of 20 meafures of carbonic acid with 10 of common
air, 10 parts of water take only 6 of carbonic acid, or 4 lefs
than in the former inftance.

An analogous fadt. was obferved by Dr. Brotvnrigg *, who Reverfe fa£h

remarked that gas does not efcape from the water which it ThaJ gas efcaPc"

, . r . much more

impregnates, unlefs the water be in contact with air: for, when readily from

the Pouhon water was excluded from air, but, at the fame time, water when lt
,., , c -r - , . . . . can 2fi"ue '"to

liberty was given tor ^ts gas to arile into an empty bladder, common air,

the gas did not fpentaneoufly feparate from the water ; but,

on the contrary, remained united with it, when expofed to the

greateft heat of our climate. When the impregnated water,

he obferves, is thus excluded from air, the gas will efcape very

flowly, at any temperature lefs than 110° of Fahrenheit, al-

* See Dr. Brownrigg's Paper on the Pouhon Water. Phil. Tranf.
Vol. LXIV.

though

234 \ EXPERIMENTS OF GASES ABSORBED BY WATER.

though fuch heat be fufficienl for the diftillation of water ; nor
can it be wholly expelled by a heat of 160° or 170°, continued
two hours. But it is well known, that water faturated with
carbonic acid gives up its gas rapidly, when freely expofed to
the atmofphere.

In fixing the proportion of carbonic acid abforbed, it is
therefore neceflfary to note the quantity of refiduum, as is done
in the following table.

Tabulated refults
of carbonic acid
abforbed by

Experi-
ment.

Tempe-
rature.

Meafures
of water.

i
Meafures
of gas.

Quantity
abforbed.

Refidue.

Abforbed by
loo inches
of water.

water*

1

55

13

32

14

18

108

2

85

13

32

11

21

84

3

55 ,

13

24

14

10

108

4

55

10

15

10

5

100

5

55

20

20

18

2

90

6

55

19

19

16,

3

84

7

85

19

19

13

6

70

8

110

10

20

6

14

60

9

110

20

20

9

11

45

Mr. Cavendifh's
refults.

Since the above table was drawn up, I have been gratified
by remarking that, in the experiments of Mr. Cavendilh, fimi-
lar variations in the quantities abforbed, were produced by the
variable amount of the refidua ; as will appear from the follow-;
ing deductions from his experiments.

At the temperature of 55Q.

1. When the gas abforbed was to the refidue as 100 to 164,i;r
100 cubical inches of water took up - - 116

2. When the abforbed gas was to the refidue as 100 to 16,
100 inches of water took up •>• 10?

3. The abforbed gas being to the refidue as 100 to 10,
100 parts of water abforbed ... I02f

4. The abforption being to the refidue as 100 to If,
100 parts of water took up -

The quality of the refiduum, I only afcertained in experi-
ments 5 and 6 of the preceding table. In experiment 5, the
refiduary two meafures contained l\,per cent, of common air,
or 0.15 of a meafure. But, of thofe, .13 exifted previoufly
in die 20 meafures of carbonic acid gas j and the 20 meafures.

Of

95 1

EXPERIMENTS OP GASES ABSORBED BY WATER. $35

of water had, therefore, only given up .02 of a meafure, or
about T-^-y of its bulk. I apprehend, however, that the whole:
of the common air was not, even thu% extricated from the
water. In experiment 6, the 3 refiduary meafures contained
\ of common air.

To judge of the influence of temperature, it is effential that Carbonic acid is
the experiments compared mould be on fimilar proportions 0faW<xl»ed2at 55°
gas and water. Thus, from a companion of experiment 1 andtities as 9 to 7.
2, it appears, that about -^ of the whole bulk abforbable at
55°, is the diminution of the quantity of abforption produced
by each elevation of 10° of temperature; and the fame in-
ference follows from various other experiments, the refults of
which I have thought it needlefs to flate *.

2. Sulphuretted Hydrogen Gas.
One hundred parts of water, at 55° of temperature, abforbSu'phuretted
86 parts of this gas, obtained from fulphutct of iron and d i 1 u te ab ftniS^at 3q al
fulphuric acid, a refidue being .left, equal in bulk to the gas and 85®, in
abforbed. At *$*, under (imilar circumftances, the faroe^a£'l*es as
quantity abforbs 78.

3. Nitrous Oxide.

At 4-19, 100 cubic inches of water take up 50 of nitrous Nitrous oxide
oxide ; and, at 70°, the fame quantity takes up only 44. Ac-is a9bfovbed «;
cording to Mr. Davy, in whole experiments, from his intimatequantjtie$ as'
knowledge of this gas, and [kill in its preparation, I place more** to 7*
confidence than in my own, 100 inches of water at 45°, take
up 54- of nitrous oxide, the refiduum being about one half the
volume of the gas abforbed.

4. Lefs abforbable Gafes.

The experiments with thofe gafes which are abforbed only Lefs abforbable
in fparing proportion by water, I could not conveniently makeSafes»
at more than one temperature ; nor, indeed, did the obje£t

* During the abforption of carbonic acid by water, the gas and
water having previously the fame temperature, there is an extrica-
tion of calcoric, Sufficient to raife the temperature of the water be-
tween \ and \ of a degree of Fahrenheit. The fame effect is pro-
duced by the condensation of Sulphuretted hydrogen, and nitrous
oxide gales, though lefs apparently. To perceive this phenomenon,
conliderable quantities ef gas and water mould be ufed.

appear

23(5 EXPERIMENTS OF GASES ABSORBED BY WATER.

appear to me worthy of the time and attention which fuch a

repetition of them would have required. Of the accurac y of

the following, however, I fatisfied m)fe!f, by repeating each

two or three times ; and with gafes of the greateit attainable

purity*

100 cubic inches of water, at 60°, abfoib,

Thefe numbers Of nitrous gas - ... 5 inches.

are corrected Oxygenous gas - - - 2.63

in the appendix. Pholphuretted hydrogen ditto - 2.14

Gafeous oxide of carbon - - 2.01

Carburetted hydrogen gas - - J .40

Azotic gas .... 1.20

Hydrogen gas - 1.08

The folubility of atmofpherical air cannot eafily be afcer-

tained ; for, as 1 (hall hereafter (hew, in a memoir on the ex-

pulfion of gafes from water by each other, air is decomposed

by agitation with boiled water, its oxygenous portion being

abforbed in preference.

Fomerftate- -From the ltatements given by various philofophers, (the

mentsofair Abbe" Nollet, Drs. Hales, Prieilley, and Pearfon,) of the

feparable from quantjty of air feparable from water of different kinds, by heat

water inaccurate n .,«- t ^ i i ii

from the portion or a diminiihed prefTure, I expected that a much larger pro-

ilill left in the portion of the gafes conftituting the atmofphere would have
been abforbed by water, than the above numbers affigh. It is
to be recollected, however, that no method hitherto discovered
detaches from water all its air; and the unknown quantity
remaining in it, after thefe modes of feparation have been em-
ployed, is to be added to that with which a given volume of
water can be artificially impregnated. Dr. Pearfon, in hi»
enquiries into the nature of the gas obtained by paffing eleclric
difcharges through water, was at great pains to purify the
fubjeel of his experiments from air, by boiling and a powerful
air pump ; but he always found, that after the full effect of both
thefe methods, electricity liberated a further, and not an incon-
fiderable, portion of air *.
Exoulfionof Common fpring water may, I think, .be fairly taken as a

gas torn fpring fpecimen of water full charged with atmofpherical air ; and,
with the view of determining the quantity and kind of gafes
extricated from it, I made the following experiment. A glafs

Phil. Tranf. for 1797,

globe

EXPERIMENTS OF GASES ABSORBED BY WATER. 237

globe, of the rapacity of 117^ cubical inches, was filled with
water frefti from the well. To its month was adapted a curved
and ftoppered tube, which held £ of an inch ; and this was alfo
filled with water. The globe was then placed in a vefTel of
brine, which was kept boiling between fix and feven hours:;
and the gafes were received over mercury. Their quantity
and quality were as follows.

No.

Cub. inches.
1.25

Confined of

Carbonic acid. Air.
0.50 0.75

Proportion of

Oxygen gas in the

refiduary air.

0.20

Its nature and
quantity.

2

1.25

0.85

0.40

0.16

3

1.63

1.23

0.40

0.16

4

0.50

0.49

001

loft by acci-
dent

4.63

Ar remaining in 7 _ ^ ~

the bent tube. $ U1:>

3.07

1.56

5.38, total gas from 117| inches of water.

But, 4^ inches of water were expelled, owing to the ex-
panfion by heat. Therefore 117| — 4£ = 113 inches of
wafer, gave 5.38 inches of gas; and 100 inches, confe-
quently, gave 4.76, of which 3.38 were carbonic acid, and
1.38 atmofpherical air. Hence, the water afforded about -^ ,

its bulk of atmofpherical air, and ■—-. of a mixture of gafes.
In this eftimate, the gas remaining in the tube is reckoned as
Carbonic acid, which may be allowed, fince the portion laft
obtained held only -^ its bulk of common air.

SECTION II.

ON THE INFLUENCE OF PRESSURE IN PROMOTING THE
ABSORPTION OF GASES; AND THE DESCRIPTION OF AN
APPARATUS FOR EXHIBITING THIS PHENOMENON.

For the purpofe of determining the ratio between the addi- Method of ope*
tion of preflure and the increafed abforption of gafes by water, gafes wereab-6
I employed the apparatus, with fome addition, which has been forbe \ under
already defcribed. The tube B was lengthened at pleafure,pre ure*
with the view of obtaining, by a column of mercury, any ad-
ditional prelfure that might be required. The veflel A, Fig. 1,

238 EXPERIMENTS OF GASES ABSORBED BY WATER;

was then filled completely with mercury, which rof'e to its
correfponding level in the tube B. A given quantity of water^
of a known temperature, and afterwards a meafured volume
of gas, were transferred into the vefl'el, in the mode already
defcnbed ; and, as the mercury, by opening the cock b, was
brought to the fame level in both legs of the fyphon, the gas>
it i* evident, mull have been tinder the ordinary weight of th«
atmofphere. A quantity of mercury was next poured into
the leg B, fufficient to lorm a column 28 inches higher thai*
the level of the mercury in A, afler this addition ; and the
bulk of the gas was again noted. This Was found to be, pretty
exaclly, f, -£-, &c. of the fpace occupied before, when one,
two, or more additional atmofpheres were applied* Britk
agitation was now ufed, as long as any abforplion took place;
and, into the tube B an affiftant poured mercury, fo as to pre-
ferve in it the excefs of 28 inches above the level of the mer*
cury in A. The degree of abforption was known by the fcal*
on A, or, more accurately, by the quantity of mercury re-
quired to fupport the elevation of 28 inches in B,

By lengthening the column in B to 56 inches, the preflur©
of two additional atmofpheres was obtained ; and this was the
utmoft extent to which the addition of weight could be carried)
without forcing the joint at D.

When the cock b was opened, and the column in each leg
thus fuddenly fell to the fame level, the water, which had been
previoufly charged with gas, under a preflure of three atmo-
fpheres, effervefced violently ; but fome time elapfed before
the additional gas, forced in by compreffion, was wholly
evolved. Thefe appearances are very ftriking and amufing;
and are well calculated for exhibition in a chemical le&ure.
The apparatus, however, I have no doubt, may be greatly
improved; but, at the diftance of nearly 200 miles from the
metropolis, I was under the neceffity of uling fuch an one as
could be conitructed by my own hands.
Improved appa- A confiderable improvement in the conftru&ion of the ap*
*«us. paratus, which would obviate the expediency of the flexible

tube D, would be the following. To the lower neck of the
veflel A, Fig. 1, let a cap and cock, with a female fcrew, be
cemented ; and let the upper end of the pipe C be terminated
by a cock with a male fcrew. Introduce the gas and water,

EXPERIMENTS OF GASES ABSORBED BY WATER. O^Q

in the manner already defcribed ; apply the increafed preflure;
and, having flint the two additional cocks, unfcrew them from
each other. The veflel A will thus be detached, and agita-
tion may be eafily applied ; after which, again fcrew it into
its former place, and, on opening the two cocks, the mercury
will rife in the veflel A. Supply the defcent in B by frefli
mercury, and proceed as before, repeating alternately the
preflure and agitation, as long as any further abforption takes
plmce.

A further amendment of the apparatus, would confift in the
fubftitution of cocks of fome other metal than brafs, which,
however perfect at firft, are always injured by the repeated
action of the mercury. If cocks of glafs could be ground Ef-
ficiently tight, metal caps with fcrews might be cemented to
them.

For obferving the increafed abforption of lefs condenfible Operation under
gafes, I found it neceflary to fubftitute a veflel of larger fize^J? "Jforbablc *
than A, and of the capacity of at leaft 50 cubical inches. It is gafes.
reprefented by the dotted lines in Fig. I, and was furniflied
with a cock and fcrew at c. As it would have been trouble-
fome to have filled fo large a veflel entirely with quickfilver,
it was filled with boiled water, with the exception of a quan-
tity of quickfilver rather exceeding the bulk of the gas em-
ployed. The gas was admitted, as ufual, from a transfer bottle,
the mercury which it replaced efcaping through the cock b.
The increafed preflure was next applied ; and the experiment
conducted as before, except that the agitation was much longer
continued.

The refults of a feries of at leaft fifty experiments, on car- General law.

bonic acid, fulphuretted hydrogen gas, nitrous oxide, oxy- Water at 1,ke

genous and azotic gafes, with the above apparatus, eftablifh always abforbs

the following general law : that, under equal circumfiances o/'tne fame bulk °*
i •»//*;/. j d Sas> however

temperature, water takes up, m all cojes, the fame volume of con- ^nfe or rare,

denfed gas as of gas under ordinary preffure. But, as the fpaces

occupied by every gas are inverfely as the compreffing force,

it follows, that water takes up, of gas condenfed by one, two, orandconfequently

more additional atmofpheres, a quantity which, ordinarily com-* mafs or ' ?***-

. . i.i tity proportional

preffed, would be equal to twice, thnce, fyc. the volume abforbed t0 tne preffure,

under the common preffure of the atmofphere. By frequent re- ,

petion of the experiments, I obtained refults differing a little

from

240 EXPERIMENTS OF GASES ABSORBED BY WATER.

from the general principle above ftated ; but, for all practical
purpofes, I apprehend, the law has been announced with
fufficient accuracy *.
Increafed tern- jn pjace 0f tr,e cocfc Qt j cemented, in one experiment, a

by condensation. very fenfible thermometer. The veflel was next filled with
mercury through the cock b ; and the tube B being alfo filled,
the cock b was (hut, and a bottle of carbonic acid gas fcrewed
on. The cock b being then opened, the mercury defcended,
and a meafured quantity of carbonic acid arofe into the veflel
A. In the fame way, a meafured quantit) of water was in-
troduced. When the denfity of the air was fuddenly doubled
by a column of quickfilver, the mercury in the thermometer,
whofe bulb was ftill furrounded by the condenfed gas, rofe
about l£ degree. On agitating the veflel, till the water en-
compafled the bulb of the thermometer, an elevation of barely
\ a degree enfued in the temperature of the water. This
afcent would probably have been greater, if the evolved heat
had not been carried off by the mercury on which the water
iloated.

Munchejler, Dec. 8th, 1802.

APPENDIX.— (Since read.)

SINCE my paper was finifhed I have found that the num-
Coj*ecYions of bers afligned in it, as indicating the quantities taken up by

the forTrin '" W^f °f f°me °f the m°re abforbable> a"d of aI1 of the Iefs
paper. abforbable gafes, are rather below the truth. The accuracy of

thefe numbers I was led to doubt by a fufpicion that due at-
tention had not always been paid, in my former experiments, to
the quality of the unabforbed refiduum. For, the theory which
Mr. Dalton has fuggefted to me on this fubject, and which ap-
pears to be confirmed by my experiments, is that the abibrp-
Abforption of tion of gafes by water is purely a mechanical effect, and that

gafes is purely j^g arnount js exactly proportional to the denfity of the gas, con-
mcchamcal. ■ • ' •: J * "r . . T' J ... . . * '

iidered abitractedly from any other gas with which it may ac-
cidentally be mixed. Conformably to this theory, if the re-
fiduary gas contain \, T\y, or any other proportion of foreign
gas, the quantity abforbed by water will be f, T%, &c. fliort
of the maximum. The proof of thefe propofitions would
lead me into a minutenefs of detail not fuited to the prefent
occafion, I therefore haften to communicate the refults of my
lateft experiments.

The

EXPERIMENTS OF GASES ABSORBED BY WATER. 241

The report which I have already given of the quantity of On the correct

carbonic acid eras abforbed under the ordinary preflTure of the quantities of the
r . . J feveral gales ab-

atmofphere I find no reafon to correct, but of fulphurated hy- forbed.

drogen gas I have effected a larger abforption than the one
before ftated, and have repeatedly obferved its amount to be
106 or 108 by 100 meafures of water, at 60° of Fahrenheit,
which temperature is to be underftood in all the following ex-
periments.

Of feveral experiments on the abforption of nitrous oxide,
I take the following as a fair example of the whole. I agitated
at three feveral times, 1175 meafures of nitrous oxide, with
1320 meafures of water; 1025 parts of gas difappeared, and
the unabforbed remainder 150 contained 15 of foreign admix-
tures. It follows that 100 parts of water had taken up 77.6
of nitrous oxide ; and after adding to thefe the diminution of
abforption occafioned by the impurity of the refidium, it may
be inferred that 100 parts of water would abforb 86 of abfo-
lutely pure nitrous oxide.

With refpecl to the remaining gafes I have been prevented
by urgent profeffional engagements, from examining the quan-
tity of each abforbable under fimilar circurattances, except in
the inftances of oxygenous, azotic and hydrogenous gafes.
The refults of thefe experiments are comprifed in the follow-
ing table. The firft column (hows the quantity of gas which
100 parts of water, at 60°, have actually abforbed ; the fe-
cond the quantity which ought to be taken up, provided the
refidue were in a ftate of abfolute purity. In the example of
nitrous gas alone, the eftimated is lefs than the actual abforp-
tion ; becaufe a fmall portion of this gas lofes its aerial form,
by union with the oxygenous gas from which water cannot be
entirely freed.

A table (hewing the quantity of each gas abforbed by 100 Table of abforp-

eafures of water at 60°.

tions of gafes

Aftual

Abforption.

Inferred Abforption.

Nitrous gas -

5.

-

- 5.

Oxygenous gas

3.55 -

- .

- 3.7

Phofphuretted hydrogen gas

2.14. -

-

-

Gafeous oxide of carbon

2.01 -

-

•

Carburetted hydrogen gas

1.40 -

-

-

Azotic gas -

1.47 -

-

- 1.53

Hydrogenous ga§

1.53 -

-

- 1.61

Vol. V.— ^-August.

R

V.O/

242 STATE OF VAPOUR SUBSISTING IN THE ATMOSPHERE.

V.

Of the State of Vapour fubfijling in the Atmofphere. By Rich akd

KirwaJ<, Esq. LLD. F. R. S. and P. R. I. A*.

{Concluded froin- Page 215.)

R. SAUSSURE, Hygrometer, p. 284-, has given us the
fpecific gravity, not indeed of pare vapour, but of vapour dif-
folvedin air, with more precifion, for he tells us, J. That a cu-
bic foot of perfectly dry air has its volume augmented by -^
when faturated with ten grains of moifture 3t about 65° Fahr. of
heat, and barometer 28,77 inches (Englifh).
Specific gravity 2. That a cubic foot of pure or perfectly dry air of that den-
moil^air.*11 ^J anc* al tnat temperature weighs 751 grains (French), and
after diflblving 10 grains of moifture, by which it is dilated 7XT,
this new volume weighs 751 -f- 10 = 761 grains; but a cubic
foot of pure air augmented by an acceffion of I of its bulk of
pure air would weigh 751 -f- -^ 751 = 765 grains, that is 14
grains more. Hence he infers that in this cafe the fpecific gra-
vity of the diflblved moifture is to that of dry air as 10 to 14,
for -jJy of a cubic foot in the one cafe weighs 10 grains, and in
the other 1 4 grains nearly.
Sufpefted errors But I ftrongly fufpeel that the original experiment, on which

in the original ^ Ca]€lliati0n is founded, is erroneous, chiefly by reafon of the
experiment* J J

ftrong adherence of moifture to cold glafs, as will hereafter be

feen in treating of dew. From Schmidt's experiments, it may
be inferred, that the fpecific gravity of vapour diflblved in air
at this temperature is much lower with refpeft to that of pure
air than Sauflure has ftated, for he tells us that about 1066
meafures of dry air in temperature 65° would, if faturated with
moifture at that temperature, occupy the fpace of about 1 100
meafures, and confequently receive an augmentation amount-
ing to about y'L of their bulk ; now, transferring this ratio to
the cubic toot in Sauflure's experiment, it appears that TL of a
cubic foot thus added to the cubic foot of dry air weighs 10
grains ; but a cubic foot of dry air, augmented by an acceffion
of y'-y of flmilarair, would weigh 751 -f- 23,46 grains, which
approaches nearly to Mr. Watt's ratio, therefore the fpecific
gravity of vapour diflblved in air at this temperature is to that
of perfectly dry air as 10 to 23,5 nearly. It ftiould however

be

JTATE 0E VAPOUR SUBSISTING IN TttE ATMOSPHERE.

243

be recolle&ed that Mr. Sauflure found that a cubic foot of dry
air in reality took up 11,069 grains of mofture when faturated
at this temperature, and that it was only by way of conceflion
to thofe againft whom he argued, that he ffoted the weight
taken up at 10 grains; then we mould have of 11,069 to
2 1 , 1 95, or in round numbers as 1 1 to 2 1 or 1 0 to 1 9. And it
mould farther be remarked, that the temperature is given very
loofely, for it is ftated to be from 14 to 15 or 16 degrees of
Reaumur. See Hygrometer , p. 104 and 284.

Sauflure has given us a table, by the help of which the ab- Table of the

folute quantity of vapour at any barometrical height, in a cubic <luant.lt,e^ of va"

r > • • i • r 1 pour ,n a,r °*

foot of air being known, the proportion and abfolute quantity different den-
in a cubic foot, at another barometrical height, 3,6 inches fitles but hkc
lower, may be known from the mercurial height 28,77 to that
of three inches and one*half, nearly.

This table I here give, adapting it to our meafures.

Thus fuppofing the abfolute quantity
of diffblved vapour at any temperature,
and barometer 28,77 to be 10 grains per
cubic foot, then the quantity of vapour
at a height at which a barometer would
ftand at. 25, 17 inches would be 10 x
0,9528 = 9,528 and at the height at
which a barometer would Hand at (even
inches, the quantity in a cubic foot would
be only 10 X ,6230 = 6,23. But flilt
it is fuppofed that at thofe great heights, at which barometers
would Hand fo low, that the air is of the fame temperature as
the original experiment is made at, namely in this cafe, as it
is found at barometer 28,77 inches ; but fince in reality air at
great heights is generally much colder than below, to afcertain
the real proportion of vapour at thofe heights it will be necef-
fary to find the quantity of vapour which a cubic foot of air is
capable of holding at that temperature barometer 28,77, and
the ratio which the quantity or weight of vapour actually found
bears to the complement at that temperature. Then, 2. to
find the complement of a cubic foot of air at the temperature
which prevails at the given barometrical height, and diminifh it
in the fame ratio in which it was found diminiihed below, and
finally diminifh it ftill farther in the ratio which that barometri-
cal height demands. An example will fully explain this rule.

R 2 Thus

Barometer

Ratio.

28,77

1,0000

25,17

0,9528

21,57

0,8899

17,97

0,8264

14,37

0,7629

10,77

0,6887

7,17

0,6230

3,57 I

0,43 1 1 1

244

mm corrcftion for
different tem-
peratures*

Syftem of Lam-
bert refpecting
the quantities o
vapour in air of
different den-
sities.

STATU OF VAPOUR SUBSISTING IN THE ATMOSPHERE.

Thus Sauffure found, barometer 28,77 and thermometer 82°
of Fahr. a cubic foot of air contained about 10 grains of moi-
fture at Geneva. Now the complement of 82° is nearly 15
grains, and the ratio of 10 to 15 is-}. Then at Mount Blanc,
on the fame hour, the barometer flood at 16° and the thermo-
meter at26°,8 ; the complement of a cubic foot of air at this
temperature is 5,3 grains, which diminifhed in the ratio of 2
to 3 becomes 3,5, and this, farther diminifhed by the ratio
which the barometrical height of 16 inches demands, namely
,78 = 3,5 x ,78 = 2,7 grains, by obfervation it was found to
be 1,7 ; the difference is only one grain. Voy. aux Alpes, §
2007. How the temperature which prevails at thofe great
heights may be found, will be (hewn in the fequel.

The celebrated Lambert, of Berlin, Mem. Berlin. 1772,
has alfo given an eltimate of the proportion of vapour which
prevails in the atmofphere at different barometrical heights,
deduced from calculations founded on many fictions, fuch as
that of an homogeneous atmofphere, of pure air difiinct from
common air, and an erroneous fyftem of the afcent of heat ;
yet as it is much eafier in its application and in the inftance
juft quoted, approaches very near the truth, I have calculated
the refults of his fyftem, which is nothing more than that the
quantity of vapour at different barometrical heights above the
earth is in the ratios of the fquares of thofe heights. By an
homogeneous atmofphere it is probable he meant fuch a ftate of
the atmofphere as prevails in ferene unclouded weather, and it
is certainly only in fuch an atmofphere that any calculation can
be inftkuted.

Table of the Ratios of the Quantities of Vapour at different barome+-
trical Heights, theQuantity of the Surface of the Earth being given.

Barometer.

Ratio of

Barometer.

Ratio of

Barometer.

R >tio of

Vapour.

Vapour.

Vaprur

30,

900

24,

576

12

144

29,5

870

23,

529

11

1 2 )

29,

841

22

484

10

100

28,5

812

21

441

9

81

28,

784

20

400

8

61

27,5

756

19

361

7

49

27,

729

18

324

6

36

26,5

702

17

289

5

25

26",

676

16

256

4

16

25,5

650

15

225

3

9

25,

625

14

196

2

4

24,5

600

13

169

1

1

Tims

STATE OF VAPOUR SUBSISTING IN THE ATMOSPHERE. 245

Thus in the example laft quoted, the quantity of vapour in
a cubic foot at Geneva being 10 grains, barometer 28,77, the
quantity on Mount Blanc, barometer 16, fliould be ,309, for
as 827,7 (:= 28,77a) is to 256 (=T6a) fo is 10 to 0,309,
which differs from the truth by only 0,391 of a grain.

As vapours unite to air, partly through the agency of heat, Separation of
and partly through that of affinity and of elearicity, fo they fe- 2^arn^f"r
parate from it, foinetimes from a diminution of that degree of heat and of
heat which they poffeffed in their nafcent ftate, fometimes from eleftricity«
a diminution of affinity, and fometimes from an alteration in
their electrical ftate.

In their firft degree of coalefcence when feparated from air, Firft coalefcence
they form aggregrates of exceeding minute particles, feparated °or ^foudsT *
from air by the diminution of affinity, and alfo from each other
by eleclrical atmofpheres ; thefe aggregates are of equal, and
often lower, fpecific gravity, than the air in which tfjey are
formed, and yet are vifible by reafon of their opacity ; when
near the earth they are called foggs, mijls or haze, (which differ
only in denfity) and when at greater heights, clouds.

Vapours ifTuing from water or moifture warmer than the air Statement of the
to which they unite, are foon cooled by it and thence in great manner in which
meafure difmifled ; hence the morning mifts obferved in fum- form€d,
mer and the winter mifts of the colder regions ; evening mifts
on the contrary proceed from the fuperfatu ration of air with
vapours previoufly diflblved, arifing from the fupervening de*
creafed temperature. The inferior ftrata of the atmofphere
are fcarce ever fuperfaturated by vapours arifing from water or.
moifture warmer than the air into which they afcend ; for be-
fore the point of faturation can be attained, their affinity to the
portion of air to which they are united is weakened, and thence
exceeded by the unincumbered affinity of the fuperior ftrata,
and this happens fucceflively on to the higher regions ; but
with diminiftied activity, by reafon of the diminished denfity
of the higher ftrata, until their ulterior progrefs is checked by
faturation ; but as they are ftill continually recruited from be-
low, their quantity is at laft fo far increafed that they coalefce
into clouds. Here the procefs recommences, for from the fur-
face of thefe clouds a frelh evaporation often takes place, which,
after fome progrefs, is again checked in its turn, and clouds
are formed at a fuperior height ; thefe again give room to a
further evaporation, and a new ftage of clouds is formed, until

the

246 STATE OF VAPOUR SUBSISTING IN THE ATMOSPHERE.

the procefs is at laft arretted by the intenfe cold of the fuperior
regions. But the mere cold of congelation is not fufficient to
arreft it, for Bouguer informs us that clouds are formed 2500
feet above the lower line of congelation, and that ice itfelf
evaporates, though cooled, feveral degrees below the freezing
point, is well known. The diftance of the particles, both of
air and vapour, from each other, when fo far rarified as they
muft be in the fuperior regions of the atmofphere prevents their
coalefcence in any but the extreme degrees of cold.
Cloud sin ftrata Hence we fee that in the warmer latitudes and feafons, va-
atove each rjous ftrata Qf cioucjs mav De formed one above the other ;
MufchenbRook atteft*, that. even in Holland, in Auguft 1748,
he diftinclly difcerned three. Thefe diftind ltrata, varioufly
* v electrified and otherwife circumftanced, give occalion to vari-
ous phacnomena, the detail of which would here be mifplaced.
Clouds near The clouds which commonly crown the fummits even of low

mountain tops, mountains, and often announce rain, are caufed by the near
approach to faturation, at thofe elevations, and its actual at-
tainment through the evaporation from thofe fummits. But
the fummits of the loftieft mountains ever crowned with fnow,
are generally (hrouded in clouds from the cold they impart to
the air in contact with them, and the lofs of electricity con-
duced away from the vapours contained in that air, by the
mountain.
Heights at which The heights at which the lowed clouds are formed are va-
clouds are r;ous jn various latitudes and feafons ; greater in the warmer

and fmaller in the colder. In latitude 54* in Cumberland,
Mr. Crofthwaite obferved none lower than 2700 feet, and
none higher than 3150 in the eourfe of feveral years*. But
this country being mountainous they are probably lower than
in others under the fame parallel. Lambert, in Berlin, lati-
tude 52° 32', in the month of July 1773, found their height
7792 (eet, thermometer 65°, and the barometer fomewhat be-
low its mean height f. Schuckburg alio remarks, that clouds
frequently reft below the fummit of Sateve, whofe height is
2831 feet. Phil Tranf. 1777, p. 538, and Gentil at Pondi-
cherry, latitude 12°, obferved fome at the height of 1024-0
feet. 2 Voy. p. 79.

* D' Alton's Meteorological Obfervations, p. 41.
f Mem. Berlin, 1773, p. 44.

The

ON VENTRILOQUISM. 247

The weight of clouds, Sauflure eftimates at one-third or clouds weigh

one-fourth of that of the cubic foot of air in which they fub- ^ one *j*f

ot the air they
fjft. Hygrometer, p. 270. When the barometer rifes, clouds float jn.

are partly diflblved, a* denfe air is a better folvent than rarer

air, and partly rife higher in confequence of the increafed

fpecific gravity of the inferior air ; when the barometer falls

the contrary takes place.

VI.

Experiments and Obfervations infupport of that Theory of Ven-
triloquifm uhich is founded on the Rtfle&ion of Sound. In a
Letter from Mr. John Gough.

To Mr. NICHOLSON.
S I R,

JL OU have given a fliort but comprehenfive yiew of my whether the
theory of ventnloquifm, at page 202, of the fourth volume ofphenomenon of
your Journal ; after which, you obferve, that the raani^ftfeferabletoe'cho?
difficulty of managing the echos of a room renders my ex-
planation of the phenomenon doubtful. In order to examine
the force of this objection experimentally, I proceeded in the
following manner: perhaps the inftruments which were ufed
on the occafion, may be deemed childifh by many of your
readers ; but a genuine friend to phyfical inquiry looks for
the event pi' an experiment, and does not regard the appear*
ance of the apparatus.

Exp. 1. I took the (hell of a cocoa-nut, one end ofgxp. i. The
which had been cut off, fo as to make it an aperture, fome- beats of a watch
thing more than two inches in diameter : after lining this with chUfl?in one
woollen cloth, I put a watch into it, and furrounded the direction. This

whole with a pillow in a manner, that left no part of the fhell ftron|e* found

r v was then re-

in contact with the atmoiphere, except the open end. When flexed by a no-
things were thus prepared, the pillow was placed upon my ta,,lc *urracc and
ii • ii r , . r , . was referred to

knees, having the mouth of the nut turned from me : I then its laft direclioju

liftened tp the foupd of the watch, fitting in an ered pofture,
and obferved it to be weak, but diftincl as to direction : a
circular metal tray, one foot in diameter, was held up before
my face, in the next place, and at the diftance of two feet
from it; upon which, the clicking of the watch grew much

ftronger,

24-8 ON VENTRILOQUISM.

ftronger, and proceeded from the tray. The certainty of the
latter circumftance was afcertained by changing the place of
the reflector, fo as to make the found fall upon my right and
left ears alternately.
Eiq>- a. A fmall Exp, 2. The refult of the laft experiment convinced me
metallic rattle 0f ^e practicability of turning the echos of a room to the ufe
inftead of the °f a ventriloquift, feeing I had employed thofe of my own
watch ; and ]ap to a fimilar purpofe ; neverthelefs I defired to give an
tried: with additional proof of the fame thing, by the afiiftance of a
fimilar iefults. ftronger found. With this view, I took a fmall metal rattle,
belonging to a child's toy ; it weighed 25 grains, and con-
fided of two thin convex (hells of brafs, fomething lef? than
one inch broad: a pellet was lodged in the cavity formed by
the junction of thefe hollow plates; the motion of which pro-
duced a found, fuch as I wanted. This rattle being put into
the fame-cocoa nut prepared as in the laft experiment, I gave
a gentle motion to it by my finger, which was introduced at
the aperture ; and I foon perceived, that the found might be
transferred in this cafe alfo, from the fhell to the tray, but
not with equal certainty : for frequently a flight change, given
to the inclination of the refleclor, rendered the place of the
found evident, which was indiftinci before ; and the contrary.
The reafon of this uncertainty will be inveftigated hereafter;
and I may add at prefent, that a thin quarto as well as a fan
were fubftituted with fuccefs, in lieu of the tray; but bodies
of three or four inches in diameter, did not produce the effect.
The preceding experiments have been related with an atten-
tion to circum (lances, which cannot fail of inftru&ing any
one to repeat them accurately ; and a few trials will, without
doubt, convince him who will take the trouble, that the echos
of a room are fubjecl to external influence, as well as thofe of
a valley.
Obfervations on We come in the next place to examine the peculiarities
the fads. The that gave rife to thefe counterfeit founds ; that is the unufual

ieflec~ted found cjrcumftances 0f my experiments are to be reviewed, and
was made to pre- j r .

dominateover, their effects afcertained. The (hell was enconi nailed by a bad

and obliterate the conr]uflor 0f found on all fides, the mouth excepted; it was
direcUound, &c. . *

from this aperture then, that the pulles entered theatmolphere

with their wonted freedom. Now we know from experience,

that confined found does not diverge from the place of its

egrefs, as it. were from a centre : for fliould any one attend to

a

ON VENTRILOQUISM. 24<9

a noife coming from an open window, he always finds it
ftrongeft, in front of the paflage ; founds therefore refemble
the properties of a river entering a lake ; the current of
which affects its former direction, after it is freed from the re-
ftraints of a channel. My ear was placed behind the ap-
paratus, in relation to the (hell's mouth ; confequently it did
not lay in the track of the direct pulfes ; therefore the found,
heard by me in the abfence of the reflector, (hall be fuppofed
at prefent to have confuted wholly of lateral pulfes, reflected
from the circumference of the aperture ; but when a greater
mafs of found was forced on the ear, from a different quar-
ter, the weaker became imperceptible; which is a thiiig,
that happens invariably in fimilar cafes; this change in the
direction of the prevailing pulfes neceffarily transferred the
feat of the found from the fhell to the reflector. But if the re-The fame effeft
fleeted lateral pulfes can be filenced in one cafe, by diverting^ y produciblc-
thofe of the centre towards the fame parts ; a like rule might
be expected to obtain in all cafes: becaufe the powers of re-
flected founds may be fuppofed to have a fixed relation to their
primitives ; but the rule fails in a number of inftances ; con-
fequently my artificial ventriloquift pofleiTes another fource of
found ; which is the next fubject of inquiry.

Exp. 3. When I let the fmall rattle tall from the height ofE*P; 3- The
. i i if i • i i- i i n m i n i rattle was let fall

an inch, upon the cloth which lined the tnell the liroke wasjn ;ts confining

heard in the nut ; but the noife, occafioned by the rebounding receptacle. The
of the pellet, came from the reflector; in this inflance then,ce tacje gave a "
we have two founds, proceeding from different places, though di eel found ;
they evidently iflued from the fame fpot ; and the caufe, thatre£0r*nd"aVe the
gave them oppofite directions, may be investigated in the reflex found t
following manner. The ftroke of the rattle gave vibrations
to the fhell, which were ftronger than thofe imparted by the
pellet ; the former fet of vibrations could not be fuppreffed by
the pillow on account of their firength, they therefore pro-
duced a found, conjointly with the lateral pulfes, which proved
an overmatch for the echo of the reflector ; while the feebler
force of the fecond fet was overpowered by the pulfes, reflect-
ed from the tray. In reality the art of fupprelling the direct The fecret of
found appears to conftitute the fecret of ventnloquifm ; foj^^jj^
the more completely this found is fmothered, the eaiier it is todirect found.
place the reflector properly : this appears to be the reafon,
why the experiment fucceeds with a watch more frequently

than

250 ON VENTRILOQUISM.

than with the rattle ; becaufe the impulfe of the former is left
than that of the latter. In fact, if the force of the founding
body be augmented, while the power of the muffle remains
unchanged, the reflector foon becomes ufelefs j as I found by
ufing a fmall bell, the found of which was difguifed with
the greateft difficulty in my rude apparatus ; and every pre-
caution, that could be taken made it a hard talk to place the
refle&or properly. The beft pofition of this bo'y is apparently
that which brings the ear in the line, conftituting ihe path o
the ftrongeft pulfes, after they are reflected ; which line and
their courfe before reflection muft make equal angles at the
reflecting furface, with a perpendicular to it; which muft alfo
lay in the fame plane with them. I have now gone through
the demonftration of a propofition, which forms the founda-
tion of my theory of ventnloquifm ; fliould you think proper
to repeat the preceding experiments, I only alk the indulgence
of a little patience on your part : treat them in other reflects
with critical accuracy ; it was my intention to fcrutinize your
theory freely ; but too much of the prefent fheet is occupied
already.

JOHN GOUGH.

Middle/haw, July 16, 1803.

REPLY. W. N".

I never meant to have exprefTed a doubt as to the interefting
facts respecting found, which Mr. Gough has dated and com-
mented upon, in his paper at page 125 of our fecond volume;
nor can it be difputed that many curious effects are produced
by the reflection and tranfmiflion of found. I am very far from
wifhing to advance any theory of an art concerning which I
have witnefled fo little ; and I take it for granted that the
ingenious author, when he fpeaks of his theory and mine, in
the laft paragraph of the preceding communication, does not
mean to fupport the pofition that the effects of what is called
ventriloquifm are exclufively produced by reflection. The
narrative of Fitz James's performance at page 202. vol. 4.
of our Journal, will at leaft prove that thecaufes which I have
founds with ap-confidered rather as moral than phyfical, muft be admitted in

SnTn^ref '^ man>' CafeS' lf n0t '" aI1' PolTib,y t,iere may be ventriloquifts
fie&ion. who operate more by the reflection of found, than by the art

of

The ventrilo-
quifm of Fitz
James was an
imitation of

EXAMINATION OF SALT OF BITUMEN. 251

of imitation affifted by theatrical action ; as Fitz James evidently
does, to a (battered audience, who cannot all, or even many
of them, be fuppofed to be duly placed for receiving one and
the fame echo : and upon a careful recollection of the pofitions,
I am much inclined to think none of them were fo placed.
The reflection of found by a fimple echo, — its more complicated Many pheno-
echo from a curved furface, or whifpering gallery, or fpeaking mena of foun4
trumpet, — its yet unexplained tranfmiffion along a fmooth wall deJufion ; but
or the furface of water, — its tranfmiffion through or along the how far ventri-
ground, fo well known to militarymen, and to which the firing of
Dr. Moyfe *, the fpeaking apparatus of Ezekiel Walker f, and
other fimilar effects, are referable. Thefe and other modes
of operation, unknown to or unthought of by me, may
furely be ufed in producing delufions and other ufeful or re-
markable effects, and may conftitute part of the art of ven-
triloquifm. I can only exprefs my opinion, that the art of the
profeffor I have fpoken of was exquifite mimicry, and nothing
more.

VII.

Examination ofthefo called Salt of Bitumen, the Bit-Nobin of the
Hindoos. By Frederick Accum, Practical Chemifi and
Teacher of Chemijlry. From the Author,

IN the LV Number of Mr. Tilloch's Philofophical Maga- Account of
zine, p. 206, we find fome obfervations concerning a faline ?Jt dum ?' 5 ^
compound lately imported from India, under the name of Salt Magazine,
of Bitumen or Bit-Nobin. From the experiments which the
author of that paper (Mr. Henderfon), made in order to be-
come acquainted with the nature of that fait, it appeared to fuppofed to be
him to be chiefly compofed of common fait and fulphurated^^^2"4
hidrogen gas. But as the experiments of this gentleman dohidrogen.
not appear to have been made with a view of affording an
analyfis of this faline fubftance, I was called upon by fome
medical practitioners of eminence to examine chemically the
nature of this curious compound. I (hall therefore confine
myfelf merely to this examination, which was conducted in the
following manner.

* Philof. Journal. f Ibid.

Upon

252 EXAMINATION OF SALT OF BITUMEN!

Alcohol by di- Upon 480 grains of the fait reduced to a fine powder, 3ozs,
geftion diflblved 0f highly rectified alcohol were poured ; the mixture was fre-
quently agitated in a flopped- vial, during the courle of one
week, and the alcohol afterwards Separated by filtration j the
fait which remained on the filtre was treated in a fimilar man-
ner, with frefh quantities of alcohol repeatedly. The different
portions of fpirit employed which were all colourlefs, had on
being mingled together a difagreeable odour and bitterilh tafte :
they were evaporated to drynefs.
which afforded On leaving the product obtained in this manner unobferved
after evap. and to tne ajr fof fQme weeks jt was fOUnd to have attracted moif-
deiiques. a

white fait and ture fo as to be feparated into two diftinct faline fubftances,
yelLwifh liquid. namely, a yellow i(h fluid, and a cryfialline white fait.
The yellow fluid To afcertain the nature of thefe faline bodies, alcohol was

bTafcohofwas affllt'ed uPon ifc in order to feparate tne liquid part from the cryf-
diluted with tallized fait. The fluid which was taken up by the alcohol, I

water and the ming|ed with a like quantity of water, heated the mixture to
alcohol driven . ,,. . , . , . . - . . ,. . et ,

off Carbonate of ebullition, and then dropt into it a lolution ot carbonate of toda.

foda threw down ^ cloudinefs appeared and a precipitate was depofited, which

' ' after being warned and dried was found to be carbonate of

lime. The refiduary fluid from which this precipitate had

been feparated yielded nothing but muriate of foda.

hence the fait j learned from thefe experiments that the fait under exami-

contains muriate ,. t . , ... c , .

of lime- nation contained muriate or lime.

the muriatic acid To determine the quantity of it contained in the above por-

of wh.ch gave a tj f ^ j i^cred it neceffary to afcertain the quantity of one
a Drecjp w th > J £> J p J

f/lutionoffllver, of its conftituent parts; for the compofition or this fait being

from the weight known the real quantity of the compound might be thence
of which the „ * mt ./ . , J . „ ,. / , , , r

quantity of mu- found. The artificial muriate of foda produced before was

nate of lime was therefore diflblved in water, and its folution decompofed by
the addition of nitrate of filver : the muriate of filver produced
when perfectly dried, weighed 40 grains, which indicate nine
grains of muriatic acid, anfwering to 12 grains of muriate of
lime. This therefore was the true quantity of muriate of lime
contained in the above quantity of fait.

The folid fait Upon the fait which had been repeatedly extracted by alco-

Xl{\ by thJ*T~A hoi, diftilled water was poured in order to diflblve it. On
hoi was diilolved * , , , • i • n i j i r

in water. It (halting the mixture, the whole acquired inftantly a dark olive

gave odour of green colour> the peculiar odour of fulphurated hidrogen gas
i"ogen"b!came was evolved and a black pulverulent precipitate became dif-

green, and fufed

afforded a black

precipitate.

EXAMINATION OF SALT OF BITUMEN.

253

fufed through the folution. To collect this precipitate the fo-
lution was filtred as expeditioufly as poflible : the precipitate
warned and dried weighed fix grains.

This precipitate to which the cau(e of the green colour of this was iroa*
the folution was owing, after having been (lowly dried, on ex-
pofure to air, had the appearance of a dark brown powder.
It was foluble in muriatic, fulphuric and nitric acids. Tincture
of galls and prufliate of potafli proved it to be an oxide of iron.
In order to be pofitive in this refpect, a like quantity of the
fame precipitate obtained in a fimilar manner, was diffolved
in fulphuric acid, and the folution again decompofed by car-
bonate of foda. The carbonate of iron was re-diffolved in di-
lute nitric acid, and repeatedly boiled to drynefs in that fluid,
till it became completely infoluble, and acquired all the pro-
perties of red oxide of iron.

The faline folution from which this oxide had been feparated, The fluid con-
had a ftrong odour of fulphurated hidrogen gas. Its tafte ta,™d ,^l?hu"
greatly refembled Harrowgate water. Mercury agitated in con-
tact with it loft its brilliancy, and became covered with a black
pellicle. Arfeniousacid immerfed into it became yellow ; leaf
filver tarniflied inftantly ; nitrous acid, holding much nitrous gas
in folution, occafioned a white precipitate ; nitrate of filver,
acetite of lead, nitrate of bifmuth, occaiioned black precipi-
tates ; muriate of barytes rendered it milky, and a precipitate
was depofited which was infoluble in muriatic acid ; prufliate
of potafli and tincture of galls had no effect upon it. All thefe
experiments (the latter three excepted) fufficiently evinced the
prefence of fulphurated hidrogen gas.

In order to afcertain the contents of the water it was eva-The faline por-
porated to drynefs: the fait obtained after having been exa- d™ ™" ™un'ac-

r - ? ,of foda with a

mined in the ufual manner, confined entirely or muriate of fmall portion of
foda, contaminated with a fmall quantity of fulphuric acid ; fulphunc acid,
its weight amounted to 444 grains. To afcertain the quantity The quantity of
of fulpnuric acid, the fait was rediflblved in water, and mu-this laft acid was
riate of barytes was added till no further precipitate enfued. precipitate br
The fulphate of barytes produced when dry, weighed 5 1| muriate of ba-
grains, which are equivalent to 14 grains of fulphur. It **2j*% , . .
perhaps needlefs to remark that, the fulphuric acid thus found acjd wa9 ruot
did not previously exift in the fait : its production was evidently or gina y fuch,
owing to the decompofition of the produced fulphurated ^^fiomniS^,
drogen gas, for no veltige of fuch acid could be detected by
any other agent, or under other circumltances.

Sulphur

254 EXAMINATION OF SALT OF BITUMEN*

which exifted Sulphur was therefore the compound which muft have beeil

jnafu!Phurctofprefent ancj tf WQ are permitteci to reafon from the pheno-
iron in the tak. , , *- ■■■; ' , -. ,. ,. .

mena which refult from the action of water upon thiscompound,

it becomes obvious that the fulphur is joined to the iron, detected
before, in the form of a fulphuret of iron. Hence it becomes
evident that while the fait continues in a dry ftate, the equili-
brium of the affinities of its constituent parts remains unaltered ;
The equilibrium but the moment we bring this compound in contact with water,
brokenby the a new arrangement of principles takes place ; the water is de-
addition ofwater.com pofed, the oxide of iron is reduced to a llate of minimum
of oxidation, and appears under the form of a black powder
diffufed through the fluid, fulphuric acid is formed by the de-
compofition of the fulphurated hidrogen gas, and thus a fet
of bodies appears which did not previoufly exift in the fiate
wherein they prefent themfelves to our view.
Component parts It is evident therefore that 480 grains of this fait yielded by

ofbit-nubin this analyfis.

about i iron; g , . .

3 fulphur ; z\ Black oxide or iron - 6 grains.

muriate of lime; Sulphur - - - - - 14

Gil common ,, . e ,.

J,,? Muriate of lime -

felt.

12
Muriate of foda - 444

476
Lofs - 4

480

How to deter- I have taken no notice in this analyfis of the quantity of
mine the fuiphu- fulphurated hidrogen gas evolved during the folution of a given
if required.6611 cluant»t>' °f !■& in a limited quantity of water, this being foreign
to my fubjeft. I merely remark that, if this is wanted to be af-
certained, it may eafily be found by introducing it into a glafs
tube clofed at the top, and furnifhed at the other extremity
with a ftopper, a weighed quantity of fait, and then adding
to it a meafured quantity of water, taking care to fill the tube
with this fluid no higher than about •§-. Having done this let
the tube be flopped, and agitate it till all the fait is diflblved,
or at leaft till no more gas is extricated. Then let the tube be
immerfed into warm water, and let it Hand undifturbed : re-
move the (topper carefully fo as to get rid of the depofited
oxide of iron, and introduce into-the faline folution tube, ni-
trous gas, in fmall quantities, till no further diminution of the
gas in the upper part of the tube takes place, or till no more

/ red

EXPERIMENTS ON INVISIBLE RAYS OF SOLAR SPECTRUM. £55

red vapours are produced by a new addition of a fmall quan-
tity of the gas. The faline folulion will now be turbid : leave
it therefore undifturbed, and a precipitate will be depofited,
which is fulphur, from the quantity of fulphur fo produced we
may learn the quantity of fulphurated hidrogen gas which was
contained in the folution, for one grain of it when perfectly
dry, are equivalent to 3.33 cubic inches of fulphurated hidro-
gen gas.

Old Compton Street, Soho,
July 20, 1803.

VIII.

Experiments on the Invifible Rays of the Solar Spectrum. By M.
Ritter, of Jena*. Communicated by M. Vicktred,
Doctor in the Univerfity of Copenhagen, to the Editors of the
Bulletin des Sciences at Faris, No. 73.

A HESE enquiries form a fequel to the experiments by which Ritter's experi-

Herfchell difcovered the exiftence of invifible calorific ravs ^^ on invi*

J hole rays,
beyond the limits of the folar fpectrum. The experiments of

M. Ritter prefent a very fimple method of proving the exift-
ence of thefe rays by the exhibition of a very curious property
which he fays is peculiar to them.

He placed muriate of filver without the folar fpectrum and The rays in the

next to the violet rays. This oxide became blackened in a c?n,fine of the
n_ • • i n-n i i • i rt-n violet reduce or

lnort time, it became ltill deeper in the violet rays, ltill more blacken the

in the blue, and fo on. muriate of filver

On the contrary, placing muriate of filver a little blackened thofe near the

next to the red rays, and without the fpectrum it quickly be- re?.render.it
,..-.. .., • , white or dif-

came white, that is to lay, it was diloxigenated. oxide it.

According to M. Ritter, thefe experiments may be per- Combuftion an4
formed very Well with phofphorus : by letting fall on it the in- e*tin&,on of*
vifible ray neareft to the red, it inftantly emits white vapours; the (ame means,
but tiie invilible rays neareft the violet are thrown on the fame
phofphorus, it inftantly becomes e\tingui(hed.

From thefe fafts, M. Ritter concludes, that there exifts with-
out the fpe&rum, and at its two extremities, invifible rays
which po.iefs the property of affifting oxigenation and difoxi-
genation.

* From the Bulletin des Sciences, Germinal, An. XI.

The

256 EXPERIMENTS ON ASTRINGENT VEGETABLES.

Negative galvs- The fame philofopher has alfo obferved a fingular coin-
nifm gives the cidence between thefe effects and thofe of galvanifm. He

fcnfation of red ; . «?

pofitive of blue, nrjds that when the eye is placed m contact with the negative
conductor of the pile, it fees every object red, bat if placed
againft the pofitive conductor it fees them blue : whence-there
appears to refult an analogy between the action of the negative
electricity and that of the red light, and of the pofitive and
the violet light.

IX.

An Account of fome Experiments and Obfervations on the Conjli-
tuent Parts of certain AJlringent Vegetables ; and on their Ope~
ration in Tanning, By Humphry Davy, Efq. Fro*
ftjfor of ' Chemiftry in the Royal Injiitution*.

S * • difco- ■"■ ^^ difcovery made by M. Seguin, of a peculiar vege-
very of the tan- table matter which is eflential to the tanning of fkin, and which
nmg matter j js p0(fefTed of the property of precipitating gelatine from its
folutions, has added confiderably to our knowledge of the con-
flituent parts of aftringent vegetables,
extended by Mr. Prou<^ nas inveftigated many of the properties of

Prouftj this fubftance ; but, though his labours, and thofe of other

chemifts, have led to various interefting obfervations, yet they
are far from having exhaufted the fubject. The affinities of
tannin have been hitherto very little examined ; and the man-
ner in which its action upon animal matters is modified by
combination with other fubftances, has been fcarcely at all
ftudied.

„ , , , At the defire of the Managers of the Royal Institution, I

purfuedbythe . r-r ■ 77.

author at the began, in September 1801, a ieries or experiments on the lub-

«kfire of the fiances employed in the procefs of tanning, and on the chemi-

Royalinftitu- , 7 J , . . ._. r . . ,

^0J^ cal agencies concerned in it. J hele experiments nave occu-

pied, ever fince, a confiderable portion of my leifure hours;
and I now prefume to lay before the Royal Society an account
of their general refults. My chief defign was, to attempt to
elucidate the practical part of the art; but in purfuing it, I
was necelfarily led to general chemical inquiries concerning
the analyfis of the different vegetable fubftances containing
tannin, and their peculiar properties.

* From the Philofophical Tranfa&ions, 1803.

3 I. OBSER-

EXPERIMENTS ON ASTRINGENT VEGETABLES. 257

I. OBSERVATIONS ON THE ANALYSIS OF ASTRINGENT
VEGETABLE INFUSIONS.

The fubftances that have been fuppofed to exift moft gene- Aftringents con-
rally in aftringent infufions are, tannin, gallic acid, and ex- JJJnfj^Tanl
tractive matter. extractive.

The prefence of tannin in an infufion, is denoted by the Tannin fhewn
precipitate it forms with the folution of glue, or of ifinglafs. J^ "dex-0
And, when this principle is wholly feparated, if the remain- trad, by faks
ing liquor gives a dark colour with the oxygenated falts of iron, aiumTn/mu-*
and an immediate precipitate with the folutions of alum and ofriate of tin.
muriate of tin, it is believed to contain gallic acid, and extrac-
tive matter.

The experiments of MM. Fourcroy, Vauquelin, and Se- Aftringent folu-
guin, have fhovvn that many aftringent folutions undergo a ^°n^ry apt t#
change by expofure to the atmofphere ; an infoluble matter
being precipitated from them. A precipitation islikewife oc-
cafioned in them by the action of heat ; and thefe circum-
ftances render it extremely difficult to alcertain, with any de-
gree of precifion, the quantities of their conftituent parts, as
they exift in the primitive combination. «

After trying feveral experiments on different methods of af-
certaining the quantity of tannin in aftringent infufions, I was
induced to employ the common procefs of precipitation by
gelatine, as being the moft accurate.

This procefs, however, requires many precautions. The Precip. of tannin

tanning principle in different vegetables, as will.be feen here- v a r'STs ^""di f-*

after, demands for its faturation different proportions of gela- ferent vege-

tine; and the quantity of the precipitate obtained by filtration, tables>

is not always exactly proportional to the quantities of tannin /}) ana by the

and gelatine in folutions, but is influenced by the degree of concentration of
, . . . _, , ,, , , , , ^ r , . ,, the folutions.

their concentration. Thus, I found that 10 grains or dry ltin-

glafs, diflblved in two ounces of diftilled water, gave, with

folution of galls in excefs, a precipitate weighing, when dry,

17 grains ; whilft the fame quantity, diflblved in fix oances of

water, produced, all other circumftances being fimilar, not

quite 15 grains. With more diluted folutions, the lofs was

ftill greater ; and analogous effects took place, when equal

portions of the fame folution of ifinglafs were adted on by equal

portions of the fame infufion of galls diluted in different de-

Vol. V. — August. S gree;

258 EXPERIMENTS ON ASTRINGENT VEGETABLES*

grees with water ; the leaft quantity of precipitate being al-
ways produced by the leaft concentrated liquor. In all cafes,*
when the weak folutions were ufed, it was obferved, that the
refidual fluid, though palled two or three times through the
filtre, (till remained more or Iefs turbid and opaque ; fo that it
is moll likely that the deficiency arofe from the continued fuf-
penfion of Come of the minutely divided folid matter in the
liquid mafs.
The folutions of The folutions of gelatine, for the purpofes of analyfis, fliould

jJJfcSi? be emPlo)'ed on,>T when q«ite frefll> and in as high a Hate of
very ftrongj faturation as is compatible with their perfect fluidity. I have
obferved, that in cafes when they approach towards the Hate
of jelly, their power of a&ing upon tannin is materially altered,
and they produce only a very flight precipitation. As the
degree of fluidity of folutions of gelatine is influenced by their
temperature, I have found it expedient, in all comparative ex-
periments, to bring them and the aftringent infufionson which
they are defigned to act, as nearly as poffible to a common
at the tempera, degree of heat. My ftandard temperature 'has been between
tare 60*. 6a and 70° Fahrenheit; and the folutions of gelatine that I

have ufed, were made by diflblving 120 grains of ifinglafs in
20 ounces of water.
If an excefs of In afcertaining the proportions of tannin in aftringent infu-
fome of the ^ &****« great care mufl be taken to prevent the prefence of any
tannin will be excefs of gelatine ; for, when this excefs exifts, I have found
redifiblved. t}iat a fma]j portion 0f tne {0\[^ compound formed is rediflblved,
and the refults of the experiment otherwife affected. It is not
difficult to difcover the precife point of faturation, if the folu-
tion of ifinglafs be added only in fmall quantities at a time, and
if portions of the clear liquor be palled through a filtre at dif-
ferent periods of the procefs, The properties of thefe portions
will indicate the quantities of the folution of gelatine required
for the completion of the experiment.
Thecomparifons That the compofition of any precipitate containing tannin
of the quantities . j ge]atjne may De known wjln a tolerable degree of preci-

of precipitant . . .

and Die*ipitate fion, it js neceflary that the ifinglafs employed in the folution,
made after ^ ancj lne new COmpound formed, be brought as nearly as poffi-
ble to the fame degree of drynefs. For this purpofe, I have
generally expofed them, for an equal time, upon the lower
plate of a fand-bath, which was feldom heated to more than

150°

EXPERIMENTS ON ASTRINGENT VEGETABLES. 259

150°. This method I have found much better than that of
drying at the temperatures of the atmofphere, as the different
flate: of the air, with regard to moifiure, materially influence
the remits. '

Mr. Hatchett has noticed, in his excellent Paper on Zoo- Ifinglafs Is gela-
phytes, &c* that ifinglafs is almoft wholly compofed of ge-tmw neai y pure'
latine, I have found, that 100 grains of good and dry ifin-
glafs contain rather more than 98 grains of matter foluble in
water. So that, when the quantity of ifinglafs, in any folu-
tion employed for acting upon aftringent infufion, is compared
with the quantity of the precipitate obtained, the difference
between them will indicate the proportion of tannin, as it exifts
in the combination.

After the tannin has been feparated from an aftringent in- After precipf-

fufion, for the purpofe of afcertaining its other component taring the tan-

l ti in i i r i i ii- inn, the fluid is

parts, 1 nave been accuftomed to evaporate the retidual liquor partiyevapo-

very flowly, at a temperature below 200°. f In this procefs, rated, and the

if it contains extractive matter, that fubflance is in part ren- Jy,,^ extraft

dered infoluble, fo as to fall to the bottom of the veffel. When taken up by

the fluid is reduced to a thick confidence, I pour alcohol upon pmt*

it. If any gallic acid or foluble extractive matter be prefent,

they will be diflblved, after a little agitation, in the alcohol ;

whilft the mucilage, if any exift, will remain unaltered, and

may be feparated from the infoluble extract, by lixiviation with

water.

I have made many experiments, with the hope of difcover-it Is difficult to

ing a method by which the respective quantities of gallic acid afcertam tne

i n- ,i •« • r i • ■ i i proportions of

and extractive matter, when they exift in lolution in the alco- gallic acid and

hoi, may be afcertained; but without obtaining fuccefs in theextra<ft in the

refults. It is impoflible to render the whole of any quantity3

of extractive matter infoluble by expofure to heat and air,

without at the fame time decompofing a portion of the gallic

* Phil. Tranf. for 1800, page 327.

f M. Deyeux has fhewn, (Annates de Chimie. Tome XVII. page
36,) that in the procefs of evaporating folutions of galls, no gallic
acid is carried over by the water, at a temperature below that of
ebullition. Many aftringent infufions, however, lofe a portion of
their aromatic principle, even in cafes when they are not made to
boil $ but this fubftance, though evident to the fmell, in the water
that comes over, cannot be detected by chemical reagents.

S 2 acid*

£50 EXPERIMENTS Otf ASTRIKGENT VEGETABLES.

acid. That acid cannot be fublimed, without being in part
deftroyed ; and, at the temperature of its fublimation, extrac-
tive matter is wholly converted into new produces.
Ether takes the Ether diflblves gallic acid; bat it has comparatively little
former m pre- ac^ion Up0n extractive matter. I have been able, in examining

ferencc, but has . r , .„..,,

little efteft as to lolutions of galls, to feparate a portion ot galhc acid by means
perfect fepara- 0f ether. But, when the extractive matter is in large quanti-
ties, this method does not fucceed, as, in confequence of that
affinity which is connected with mats,*, the greateft part of
the acid continues to adhere to the extract.
Alumineattra&s Alumine has a ftrong attraction for extractive matter ; but
e*tra.a, but does comparatively a weak one for gallic acid f. When carbonate

not feparate it ,. , . . J . .. &. '" . .

perfectly from of alumine is boiled for fome time with a folution containing
gallic acid. extractive matter, the extractive matter is wholly taken up by

the earth, with which it forms an infoluble compound ; but>
into this compound, fome of the gallic acid appears likewife
to enter ; and the portion remaining diflblved in the folution
is always combined with alumine.
This problem I have not, in any inftance, been able to feparate gallic acid

fofv^f perfeaIy and extradive matter perfedly from each other; but I have
generally endeavoured to form fome judgment concerning their
relative proportions, by means of the action of the faltsof alu«*
Approximation, mine, and the oxygenated falts of iron. Muriate of alumine
precipitates much of the extractive matter from folutions, with-
out acling materially upon gallic acid ; and, after this precipi-
tation, fome idea may be formed concerning the quantity of
the gallic acid, by the colour it gives with the oxygenated ful-
phate of iron. In this procefs, however, great care mull be
taken not to add the folution of the ful phate of iron in excefs ;
for, in this cafe, the black precipitate formed with the gallic
acid will be rediflblved, and a clear olive-coloured fluid only
will be obtained.
The faline parts The faline matters in aftringent infufions, adhere fo ftrongly
of aftrmgent to tj]e vegetable principles, that it is impoffible to afcertain their

alio fcarcely to nature with any degree of accuracy, by means of common re-
be feparated.

* See Berthollet, Recberches fur Us Lois de VAffinitL Mem. de
Vlnjiitut National. Tome III. p. 5.

f See Fiedler, Journal de Chi?nit> par J. B. Van-mons, Tome I.
page 85.

agents.

EXPERIMENTS ON ASTRINGENT VEGETABLES; C2Q\

agents. By incineration of the products obtained from the
evaporation of aftringent infufions, I have ufually procure'd car-
bonate of lime and carbonate of potato.

In the different analyfes, as will be feen from the refults The practical
given in the following fections, I have attended chiefly to the precipitatlo/
proportions of the tanning principle, and of the principles pre- with gelatine and
cipitable by the falts of iron, as being mod connected with Jj£ falt3 of
practical applications.

With regard to the knowledge of the nature of the different

fubftances, as they exift in the primitive aftringent infufion,

we can gain, by our artificial methods of examination, pnly

very imperfect approximations. In acting upon them by re- Though ftri£r

agents, we probably, in many cafes alter their nature; and "*ly([?L,s !?erC ,

very few of them only can be obtained in an uncombined ftate. yet the experi-

The comparifon, however, of the products of different expe- **Jt! ,eadito
. . ufeful conalu-

riments with each other, is always connected with fome ufeful flons.

conclufions ; and the accumulation of facts with regard to the

fubject, muft finally tend to elucidate this obfcure but moft

interefting part of chemiftry.

II. EXPERIMENTS ON THE INFUSIONS OF GUIS.

I have been very much affifted in my inquiries concerning
the properties of the infufions of galls, by the able Memoir of
M. Deyeux, on galls. *

The ftrongeft infufion of galls that I could obtain, at 56° Go1<1 Infufion of

Fahrenheit, by repeatedly pouring diftilled water upon the J°i^"y"SJ^

beft Aleppo galls broken into fmall pieces, and fuffering it to grains of folid

remain in contact with them till the faturation was complete, matter> which

■'•■■• T ' was nine parts
was of the fpecific gravity 1.068. Four hundred grains of it tannin and one

produced, by evaporation at a temperature below 200?, fifty- 8allic acid#

three grains of fold matter; which, as well as I could eftimate,

by the methods of analyfis that have been juft defcribed, con-

$(ted of about -j% of tannin, or matter precipitable by gelatine,

and -j1^ of gallic acid, united to a minute portion of extra&ive

matter.

100 grains of the folid matter obtained from the infufion, The infufion

left, after incineration, nearly 4| grains ofafhes; which were j£S« «£?'

chiefly calcareous matter, mixed with a fmall portfon of fixed left byinciaera-

. tipn al ne i-2oth»

* Annates de Chimie, "Tome XVII. page 1. . «,. J^ c&n

alkali, alkali.

0(52 EXPERIMENTS ON ASTRINGENT VEGETABLES,

alkali. The infufion ftrongly reddened paper tinged with
liUpus. It was femitranfparent, and of a yellowifh-brown co-
lour. Its tafte was highly aftringent.
Sulph. acid pre- When fulphuric acid was poured into the infufion, a denfe
cipicates the fo- wj,i^jj, precipitate was produced ; and this effect was conftant,
whatever quantity of the acid was ufed. The refidual liquor,
when paffed through the filtre, was found of a (hade of colour
deeper than before. It precipitated gelatine, and gave a dark
colour with the oxygenated fulphate of iron.
This precip. The folid matter remaining on the filtre, flightly reddened

feemed to be the vegetable blues; and, when diflblved in warm water, copioufly
and gallic acid precipitated the folutions of ifinglafs. M. Prouft,* who firft
and fome pajc[ attention to its properties, fuppofes that it is a compound

of the acid with tannin : but I fufpect that it alfo contains
gallic acid, and probably a fmall portion of extractive matter.
This laft fubftance, as is well known, is thrown down from its
folutions by fulphuric acid ; and I found, in diftilling the pre-
cipitate from galls by fulphuric acid, at a heat above 21 2Q, that
a fluid came over, of a light yellow colour, which was ren-
dered black by oxygenated fulphate of iron ; but which was
not altered by gelatine.
Muriatic acid Muriatic acid produced, in the infufion, effects analogous to

thiewdowna ^ (_nofe produced by fulphuric acid ; and two compounds of the
ancfac'id, and a acid and the vegetable fubfrances were formed: the one united
fimilar com- to excefs of acid, which remained in folution ; the other con-
excels of acid taining a confiderable quantity of tannin, which was precipi-
contmued dif- tated in the folid form.

folved* ., When concentrated nitric acid was made to acl upon the

N'tric acid . . . ... - . r .. , . ,

deftroyed both infufion, it was rendered turbid ; but the lolid matter formed

principles and was immediately diffolved with effervelcence, and the liquor

exZTcl.2 m ° ^en became clear, and of an orange colour. On examining

it, it was found that both the tannin and the gallic acid were

deftroyed ; for it gave no precipitate, either with gelatine or

the falts of iron, even after the refidual nitric acid was fatu-

rated by an alkali. By evaporation of a portion of the fluid,

a foft fubitance was obtained, of a yellowifh brown colour,

and of a flightly fourifh tafie. It was foluble in water, and

precipitated the nitro-muriate of tin, and the nitrate of alu-

* The faft of the precipitation of folution of galls by acids, was
noticed by M. Dize. Ste Annates de C/jimie, Tome XXXV. p. 37.

1 mine ;

EXPERIMENTS ON ASTRINGENT VEGETABLES, 263

mine; fo that its properties approached to thofe of extractive
matter ; and it probably contained oxalic acid, as it rendered
turbid a folution of muriate of lime.

When a very weak folution of nitric acid was mixed with Weak nitric acid
the infufion, a permanent precipitate was formed, and the re_ th/othe^ acids,
fidual liquor, examined by the folution of gelatine, was found
to contain tannin.

A folution of pure potafh was poured into a portion of the Pure potafh
infufion. At firft, a faint turbid appearance was percefved ; c^^ne^ wi^k
but, by agitation, the fluid became clear, and its colour changed the tannin,
from yellow brown to brown red ; and this laft tint was moft which did not

J ' 4 * . then Separate

vivid on the furface, where the folution was expofed to the t,y geiacine till
atmofphere. The folution of ifinglafs-did not aft upon the an acid had takqp

the a:kali.

in fu(i on modified by the alkali, till an acid was added in excefs,
when a copious precipitation was occasioned.

The compound of potafh and folution of galls, when eva- The alkaline
porated, appeared in the form of an olive-coloured mafs, which ra^bTevapo-"
had a faint alkaline tafte, and which ilowly deliquefced when ration,
expofed to the air.

Soda acted upon the infufion in the fame manner as potafh ; Soda acted like
and a fluid was formed, of a red-brown colour, which gave nopota *
precipitate to gelatine. • .

Solution of ammonia produced the fame colour as potafh and Ammonia,
foda, and formed fo perfect an union with the tannin of the
infufion, that it was not acted upon by gelatine. When the
compound liquor was expofed to the heat of boiling water, a
part of the ammonia flew off, and another part reacted upon
the infufion, fo as to effect a material change in its properties.
A considerable quantity of infoluble matter was formed ; and
the remaining liquor contained little tannin and gallic acid, but
a considerable portion of a fubftance that precipitated muriate
of tin, and the falts of al umine.

When the experiment on the ebullition of the compound of
the infufion and ammonia was made in clofe veffels, the liquor
that came over was strongly impregnated with ammonia ;
its colour was light yellow, and, when fatiirated with an acid,
it was very little altered by the falts of iron. The refidual
fluid, after the procefs had been continued for fome time, as
in the oiher cafe, precipitated gelatine flightly, but the falts
of alumine copioufly ; and it gave a tinge of red to litmus
paper.

When

264> EXPERIMENTS ON ASTRINGENT VEGETABLES.

Viroe, (Irontia, When folulion of lime, of ftrontia, or of barytes, was poured
cxcef^ Threw *n exce^ ,nto a portion of the infufion, a copious olive-coloured
down nearly the precipitate was'formed, and the folution became almoft clear,
whole contents. and ^ reddifti tint. In this cafe, the tannin, the gallic acid,
and the extractive matter, feemed to be almofl: wholly carried
down in the precipitates; as the refidual fluids, when faturated
by an acid, gave no precipitate to gelatine, and only a very
flight ti«nt of purple to oxygenated fulphate of iron.
Effect of fmallcr When the folutions of the alkaline earths were ufed only in
fmall quantities, the infufion being in excefs, a fmaller quantity
of precipitate was formed, and the refidual liquor was of an
olive-green colour ; the tint being darkefl in the experiment
with the barytes, and lighted in that with the lime. This fluid,
when examined, was found to hold in folution a compound of
gallic acid and alkaline earth. It became turbid when acled
on by a little fulphuric acid ; and, after being filtrated, gave a
black colour with the folutions of iron, but was notacled upon
by gelatine.
Effect of lime When a large proportion of lime was heated for fome time
more particularly wjlh t|ie jnfuf10Ilj jt combined with all its conftituent principles,
and gave, by warning, a fluid which had the tafle of lime-water,
and which held in folution only a very fmall quantity of ve-
getable matter. Its colour was pale yellow ; and, when fatu-
rated with muriatic acid, it did not precipitate gelatine, and
gave only a flight purple tinge to the folutions of the falts of
iron. The lime in combination with the folid matter of the
infufion, was of a fawn colour. It became greet) at its furface,
where it was expofed to the air; and, when wafhed with large
quantities of water, it continued to give, even to the laft por-
tions, a pale yellow tinge. .
alfo of magnefia. Magnefia was boiled in one portion of the infufion for a few
hours; and mixed in excefs with another portion, which was
fuffered to rejnain cold. In both cafes, a deep green fluid was
obtained, which precipitated the falts of iron, but not the folu-
tions of gelatine ; and the magnefia had acquired a grayifh-
green tint. Water poured upon it became green, and acquired
the properties of the fluid at fiift obtained. After long wafning,
the colour of the magnefia changed to dirty yellow ; and the
]afl portions of water made to act upon it were pale yellow, and
altered very li t tie the folutions of iron.

3 When

KXPER1MSNTS ON ASTRINGENT VEGETABLES. £>65

When the magnefia wasdiflblved in muriatic acid, abrownifti Muriatic folu*
and turbid fluid was obtained, which precipitated gelatine and '&>« of mag-
the oxygenated falts of iron. So that there is every reafon^to
believe, that the earth, in acting on the aftringent infufion, had
formed two combinations ; one containing chiefly gallic acid,
which was eafily foluble in water ; the other containing chiefly
tannin, which was very difficultly foluble.

Alumine boiled with the infufion became yellowim-gray, Alumina
and gave a clear white fluid, which produced only a tinge of
light purple in the folutions of iron. When the earth * was
employed in very fmall quantity, however, it formed an info-
luble compound only with the tannin and the extract ; and the
refidual liquor was found to contain a gallate of alumine with
excels of acid.

The oxides of tin and of zinc, obtained by nitric acid, were Effecl: of the

boiled with feparate portions of the infufion for two hours. In J?1?" °[ " Jin.an*
r r zinc on the m-

both cafes, a clear fluid, which appeared to be pure water, was fufion. They

obtained ; and the oxides gained a tint of dull yellow. A part *? 'zed, the ■*■

r l r i !•«• i i • • • • i m, r , . »olved matter,

of each ot them was dinolved in muriatic acid. The ioIutionand a muriatic

obtained was yellow : it copiouily precipitated gelatine; and folution of the

gave a denfe black with the falts of iron. Mr. Prouft f, whocjpitate^gekJjne

firft obferved the action of oxide of tin upon aftringent infu-and gave a black

fions, fuppofes that portions of tannin and gallic acid are

decompofed in the procefs, or converted, by the oxigen of

the oxide, yito new fubftances. Thefe experiments do not,

however, appear to confirm the fuppofition.

M. Deyeux obferved, that a copious precipitation was The precipitate

occafioned in infufion of galls, by folutions of the alkalis. by, alk*lis/»™

ta ' VJ re ' &a,ls 1S n0t

combined with carbonic acid. Mr. Prouft has fuppofed that pure tannin as

the folid matter formed is pure tannin, Separated from its fo- ^ouftfuppofes;

Jution by the ftfonger affinity of the alkali for water; and he

recommends the procefs, as a method of obtaining tannin.

In examining the precipitate obtained by carbonate of potaffi for it is not af-

fully combined with carbonic acid, and ufed to faturation, I ''"J??1*' "°f
•> * * well foluble in

have not been able to recognize in it the properties which are cold water or

ufuallv afcribed to tannin: it is not poflefled of the aftringent a,<;onoi* nor.

n ,.., «• ri''A it'i -ij • iTi a"s on Ratine,

tafte ; and it is but flightly foluble in cold water, or in alcohol. nor tans~ikins.

# Mr. Fiedler, I believe, firft obferved the action of alumine upon
tannin. Van-Mons's Journal, Vol. I. p. 86.
f Annates de Gbimie, Toine XLII. p. C9.

Itl

266 fcXPKRlMKNTS ON ASTRINGENT VEGETABLES.

Its folution acts very little upon gelatine, till it is faturated
with an acid ; and it is not poflefled of the property of tanning
fkin.

In various cafes, in which the greateft care was taken to ufe
no excefs, either of the aftringent infufion or of the alkaline
folution, I have found the folid matter obtained poflefled of

Jt contains analogous properties: and it has always given, by incinera-
* tion, a confiderable portion of carbonate of potato, and a fmall

quantity of carbonate of lime.

The remaining The fluid remaining after the feparation of the precipitate,

alkali, was °^ a dark-brown colour, and became green at the fur face,

when it wasexpofed to the air. It gave no precipitate to folu-
tion of gelatine ; and afforded only an olive-coloured precipi-
tate with the falts of iron.

exhibited tanin When muriatic acid was poured into the clear fluid, a violent

,when t e a ai effervefcence was produced ; the fluid became turbid ; a pre-
was facu rated r '

with mur. acid, ci pi tate was depofited ; and the refidual liquor acled upon

gelatine and the falts of iron, in a manner fimilar to the pri-
mitive infufion.
Cryftals of gallic M. Deyeux, in diftilling the precipitate from infufion of galls
from^he^re- by carbonate of potato, obtained cryftals of gallic acid. In
cipitate. following bis procefs, I had fimilar refults j and a fluid came

over, which reddened Htmus-paper, and precipitated the falts
of iron black, but did not a& upon gelatine.
The precip. was When the precipitate by carbonate of potato was a61ed upon
warm water i ^9 warm water> applied in large quantities, a confiderable
portion of it was diflblved ; but a part remained, which could
not in any way be made to enter into folution ; and its pro-
perties were very different from thofe of the entire precipitate.
It was not at all affected by alcohol : it was acled on by mu-
riatic acid, and partially diflblved; and the folution pre-
cipitated gelatine and the falts of iron. It afforded, by in-
cineration, a confiderable portion of lime, but no alkali.
Hence the In comparing thefe fads, it would feem, that the precipitate

|wecip. wastaninfrom infufion of galls, confifts partly of tannin and .gallic acid
with a little united to a fmall quantity of alkali, and partly of thefe vegeta-
alkali, and a!fo ble matters combined with calcareous earth ; and it will appear
lime '""both car- Pr°bable, when the fads hereafter detailed are examined, that
bonated. both the potato and the lime are contained in thefe compounds

in a Irate of union with carbonic acid.

The

EXPERIMENTS ON ASTRINGENT VEGETABLES. 2^7

The folutions of carbonate of foda and of carbonate of Habitudes of
ammonia, both precipitated the infufion of galls in a manner ammonL^nearl^
fimilar to the carbonate of potafli ; and each of the precipitates, as thofe of pot-
when afted on by boiling water, left a fmall quantity of infolu-ilflx,
ble matter, which feemed to confift chiefly of tanpin and car-
bonate of lime.

The entire precipitate by carbonate of foda produced, when Particular detail,
incinerated, carbonate of foda and carbonate of lime. TheT*e?rcClJPlCate:
precipitate by carbonate of ammonia, when expofed to a heat
fufficient to boil water, in a retort having a receiver attached
to it, gave out carbonate of ammonia, (which was condenfed
in fmall cryfials in the neck of the retort,) and a yellowith
fluid, which had the ftrong fmell and tafte of this volatile fait.
After the procefs of difiillation, the folid matter remaining was
found of a dark brown colour ; a part of it readily diiTolved
in cold water, and the folution a£ted on gelatine.

The refidual fluid of the portions of the infufion which had The refidual
been acled on by the carbonates of foda and of ammonia, as in U1 '
the inftance of the carbonate of potafli, gave no precipitate
with gelatine, till they were faturated with an acid j fo that,
in all thefe cafes, the changes are frriclly analogous.

The infufion of galls, as appears from the analyfis, contains Infufion of
jn its primitive ftate calcareous matter. By the a&ion of the J.J * *ontain*
mild alkalis, this fubftance is precipitated in union with a por- matter,
tion of the vegetable matter, in the form of an infoluble com- •
pound. The alkalis themfelves, at the fame time, enter into
actual combination with the remaining tannin and gallic acid ;
and a part of the compound formed is precipitated, whilif.
another part remains in folution.

When the artificial carbonates of lime, . magnefia, and Carbonates of
barytes, were feparately boiled with portions of the infufion ofaikall?c earths
galls for fome hours, they combined with the tannin contain- cip.
ed in it, fo as to form with it infoluble compounds; and, in
each cafe, a deep green fluid was obtained, which gave no The fluid fhevr-
precipitate to gelatine, even when an acid was added, but ed no tanin, \
which produced a deep black colour in the folutions of the
falts of iron.

Sulphate of lime, when finely divided, whether natural or Sulphate of
artificial, after having been long heated with a fmall quantity "me feized the
of the infufion, was found to havecoinbined with the tannin of j*"|n y
it, and to have gained a faint tinge of light brown. The liquid

became

2tfS

EXPERIMENTS ON HSTKINGENT VEGETABLES.

Solutions of
neutral felts
preeip. Inf.
galls, but it is
not pure tanin.

Metallic folu-
tions give denfe
preeip.

probably con-
taining fomc of
the acid.

Muriate of tin.

Oxigenated ful-
phate of iron.

became of a blue-green colour, and acted upon the falts of iron,
but not upon gelatine ; and there is every reafon to fuppofe,
that it held in folution a triple compound, of gallic acid, ful*
phuric acid, and lime.

We owe to Mr. Prouft, the difcovery that different folutions
of the neutral falts precipitate the infufion of galls ; and he
fuppofes, that the precipitation is owing to their combining with
a portion of the water which held the vegetable matter in folu-
tion. In examining the folid matters thrown down from the
infufion, by fulphate of alumine, nitrate of potafh, acetite of
potafh, muriate of foda, and muriate of barytes, I found them
foluble, to a certain extent, in water, and poflefled of ihe
power of acting upon gelatine. From the produces given by
their incineration, and by their diftillation, I am however in-
clined to believe that they contain, befides tannin, a portion
of gallic acid and extractive matter, and a quantity of the fait
employed in the primitive folution.

It is well known, that many of the metallic folutions occafion
denfe precipitates in the infufion of galls ; and it has been
generally fuppofed, that thefe precipitates are compofed of
tannin and extractive matter, or of thofe two fubflances and
gallic acid, united to the metallic oxide ; but, from the ob-
fervation of different proceffes of this kind, in which the falts
of iron and of tin were employed, I am inclined to believe,
that they contain alfo a portion of the acid of the faline com-
pound.

When the muriate of tin was made to a6t upon a portion of
the infufion, till no more precipitation could be produced in
it, the .fluid that paflfed through the filtre ftill acted upon gelatine
and feemed to contain no excefs of acid ; for it gave a pre-
cipitate to carbonate of potafli, without producing effer-
vefcence. The folid compound, when decompofed by ful-
phuretted hydrogen, after the manner recommended by Mr.
Prouft, was found ftrongly to redden litmus-paper, and it
copioufly precipitated nitrate of filver : whereas, the primitive
infufion only rendered it flighlly turbid ; fo that there is every
reafon to believe, that the precipitate contained muriatic
acid,

By paffing the black and turbid fluid, procured by the action
of folution of oxigenated fulphate of iron in excefs upon a
portion of the infufion, through finely-divided pure flint, con-
tained

EXPERIMENTS ON ASTRINGENT VEGETABLE!. QQQ

tained in four folds of filtrating paper, I obtained a light olive-
green fluid, in which there was no excefs of fulphuric acid,
and which I am inclined to fuppofe was a folution of the com-
pound of gallic acid and fulphate of iron, with fuperabundance
of metallic fait. I have already mentioned that gallic acid,
when in very fmall proportion, does not precipitate the
oxigenated falts of ire i; and Mr. Prouft, in his ingenious
paper upon the difference of the falts of iron, has fuppofed
that, in the formation of ink, a portion of the oxide of iron in
union with gallic acid is ditTolved by the fulphuric acid of the
fulphate. This comes near to the opinion that they form a
triple compound : and, in reafoning upon the general pheno-
mena, it feems fair to conclude, that, in the cafe of the pre-
cipitation of tannin by the falts of tin and of iron, compounds
are formed, of tannin and the falts ; and that, of thefe com-
pounds, fuch as contain tin are (lightly folubie in water, whilfi
thofe that contain iron are almoft wholly infoluble.

In examining the aclion of animal fubftances upon the infu- Animal matter*
lion of galls, with the view of afcertaining the compolition of3r * ein*ufi<*
the compounds of gelatine, andoflkin, with tannin, I found
that a fatu rated folution of gelatine, which contained the
folubie matter of 50 grains of dry ifinglafs, produced from the
infufion a precipitate that weighed nearly 91 grains ; and, in
another inftance, a folution containing 30 grains of ifinglafs,
gave about 56* grains ; fo that, taking the mean of the two ex-
periments, and allowing for the fmall quantity of infoluble
matter in ifinglafs, we may conclude, that 100 grains of the Precipitate fey

compound of gelatine and tannin, formed by precipitation eelatine cootai»»

- r , / ,. , . 54 gelatine and

from faturated folutions, contain about 54- grains or gelatine, 46 tanin nearly.

and 46 of tannin.

A piece of dry calf- (kin, perfectly free from extraneous A (kin quickly
matter, that weighed 180 grains, after being prepared ^SStttt^MwS
tanning by long immerfion in water, was tanned in a portion ikin and one
of the infufion, being expofed to it for three weeks. When veSetable matter*
dry, the leather weighed 295 grains : fo that, confidering
this experiment as accurate, leather quickly tanned by means
of an infufion of galls, con fi ft s of about 61 grains of (kin, and
39 of vegetable matter, in 100 grains.

After depriving a portion of the infufion of all its tanning Jn« exhaufted
matter, by repeatedly expofing it to the adtion of pieces of ed Jefs |(jc
ikin, I found (hat it gave a much (lighter colour to oxigenated acid j probably

fulDhatefromd?comPofi'

270

EXPERIMENTS ON ASTRINGENT VEGETABLES'*

fulphate of iron, than an equal portion of a fimilar infufior!
which had been immediately precipitated by folution of
ifinglafs ; but I am inclined to attribute this effect, not to any
abforption of gallic acid by the fkin, but rather to the decom-
position of it by the long continued action of the atmofpkere j
for much infoiuble matter had been precipitated, during the
procefs of tanning, and the refidium contained a fmall portion
of acetous acid.

Component parts In ascertaining the quantity of tannin in galls, I found that

•f Aleppo gallc ajqq grains 0f g00(j Aleppo galls gave, by lixiviation with pure
water till their foluble parts were taken up, and fubfequent
flow evaporation, 185 grains of folid matter. And this matter*
examined by analyfis, appeared to confift,

Solid matter. Of tannin .--.-„ 130 grains.

Of mucilage, and matter rendered infoiuble by
evaporation - - - - - -12

Of gallic acid, with a little extractive matter 3 1

Remainder, calcareous earth and faline matter 12

JUfidual fluid. The fluid obtained by the laft lixiviation of gulls, as M. Deyeux-
obferved, is pale green ; and I am inclined to believe, that it
' v is chiefly a weak folution of gallate of lime. The afhes of galls,
deprived of foluble matter, furnifh a very considerable quantity
of calcareous earth. And the property which M. Deyeux
discovered in the liquor of the laft lixiviations, of becoming
red by the a&ion of acids, and of regaining the green colour
by means of alkalis, I have obferved, more or lei's, in all the
foluble compounds containing gallic acid and the alkaline
eaTths.

III. EXPERIMENTS AND OBSERVATIONS ON CATECITU
OR TERRA JAPONICA.

Catechu or terra The extract called catechu is faid to be obtained from the^
japomca. WOod of a fpecies of the Mimofa *, which is found abundantly

in India, by decoction and fubfequent evaporation.
Hiftory and ex- There are two kinds of this extract ; one is fent from Bom-
tcrnal characters ^ the ()tner from ]3engal . and they differ from each other
from Bombay J . , . , 1} . , . . . ,

acwi Bengal. more in their external appearance than in their chemical com-

pofition. The extract from Bombay is of an uniform texture,
and of a red-brown tint, its fpecific gravity being generally

See Kerr. Medical Obfervations, Vol. V. p. 155.

about

EXPERIMENTS ON ASTRINGENT VEGETABLES. 271

about 1.39. The extract from Bengal is more friable, and left
confident; its colour is like that of chocolate externally, but,
when broken, its fracture prefents ftreaks of chocolate and of
red-brown. Its fpecific gravity is about 1.28. Their tafies
are precifely fimilar, being aftringent, but leaving in the mouth
a fenfation of fweetnefs. They do not deliquefce, or appa-
rently change, by expofure to the air.

The difcovery of the tanning powers of catechu, is owing to Sir J. Bank*
the Prefident of the Royal Society, who, concluding from its J^iJ^jJjJ,
fenfible properties that it contained tannin, furnilhed me, intanin.
December, 1801, with a quantity for chemical examination.

In my firft experiments, I found that the folutions of catechu Experiments
copioufly precipitated gelatine, and fpeedily tanned (kin ; and, *?* ™* trutil
in confequence, I began a particular inveftigation of their clufion.
properties.

The llrongefl infufions and decoctions of the two different Both kinds agree
kinds of catechu, do not fenfibly differ in their nature, or in &Ct '

their composition. Their colour is deep red-brown, and they
communicate this tinge to paper; they (lightly redden litmus-
paper ; their tafte is highly aftringent, and they have no per-
ceptible fmell.

The ftrongefl infufions that I could obtain from the two kinds The ftrongcft
of catechu, at 4S° Fahrenheit, were of the fame fpecific gra-^^0™ of
vity, 1.057. But, by long decoction, I procured folutions of
1.102, which gave, by evaporation, more than £ of their
weight of folid matter.

Five hundred grains of the ftrongeft infufion of catechu from afforded 41 foJid
Bombay, furnilhed only 41 grains of folid matter; which, JSJ^S'Jt
from analyfis, appeared to confift of 34 grains of tannin, or7 peculiar ex*
matter, precipitable by gelatine, and 7 grains that were chiefly tra"#
a peculiar extractive matter, the properties of which will be
hereafter defcribed. The quantity of folid matter given by the
ftrongeft infufion of the Bengal catechu, was the fame, and
there was no fenfible difference in its compofition. Portions
of thefe folid matters, when incinerated, left a refiduum which
feemed to be calcareous; but it was too frnall in quantity to be
accurately examined, and it could not have amounted to more
than j^ of their original weights.

The ftrongeft infufions of catechu acted upon the acids and The Infufion
pure alkalis in a manner analagous to the infufion of galls. acATand alk^S* ;
With the concentrated fulphuric and muriatic acids, they gave

denfe

fnagnefia.

272 XXPSR1MENTS ON ASTRINGENT VEGETABLES.

cfenfe light fawn coloured precipitates. With ftrong nitrous
acid they effervefced ; and loft their power of precipitating th<j
folutions of ifinglafs, and the falts of iron. The pure alkalis
entered into union with their tannin, fo as to prevent it from
being acted upon by gelatine.
— with the fo- When the folutions of lime, of ftrontia, or of barytes, were
fuble earths. poured into the infufions, copious precipitates, of a thade of light
brown, were formed ; and the refidual fluid aflumed a paler
tint of red, and was found to have loft its power of precipi-
tating gelatine,
time, magnefia, After lime had been boiled for fome time with a portion of
carbonate of the infufion, it aflumed a dull red colour. The liquor that
paITed from it through the riltre had only a faint tint of red,
did not act upon gelatine, and feemed to contain only a very
fmall portion of vegetable matter. Pure magnefia, when heated
with the infufion, acted upon it in an analogous manner ; the
magnefia became light red, and the refidual fluid had only a
very flight tinge of that colour. With carbonate of magnefia,
the infufion became deeper in colour, and loft its power of
precipitating gelatine; though it ftill gave, with oxygenated
fulphate of iron, a light olive precipitate.
Carbonates of The carbonates of potafli, of foda, and of ammonia, in their

potato, foda, concentrated folutions, produced onlv a flight degree of turbid-
ammoma. _ - • t , ^ ' J .,

nets in the infufion of catechu ; they communicated to them a

darker colour, and deprived them of the power of acting upon
gelatine ; though this power was reftored by the addition of
an acid.
Expofare to the After the mixture of the folution of carbonate of potafli and
*r* the infufions had been expofed to the atmofphere for fome

hours, a brown crufl was found to have formed upon its furface,
and a flight precipitation had taken place
Aluminous falts The falts of alumine precipitated the infufions, but lefs co-
catechu.10" ° P'oufly than they precipitate the infufion of galls. A fimilar
effect was produced by nitrate of potafli, fulphate of magnefia,
prufliate of potafli, and many other neutral falts.
Kitrate or ace- The nitrate, or acetite, of lead, in concentrated folution,
ticeof lead. when poured into the infufion, produced in it a denfe light
brown precipitate, which gave to the fluid a gelatinous appear-
ance. After this effect, there was no free acid found in it;
and both the tannin and the extractive matter feemed to have
been carried down, in union with a portion of the metallic fait.

The

fcXPERtMENTS ON ASTRINGENT VEGETABLES. 273

The folution of muriate of tin, acted upon the infufion of Muriate of tin,
Catechu in a manner fimilar to that in which it acts upon the
infufion of galls.

The leaft oxygenated fulphate of iron produced no change in Sulphates of
the infufion. With the moft oxygenated fulphate it gave a denfe
black precipitate, which, when difTufed upon paper, appeared
rather more inclined to olive than the precipitate from galls.

The infufions were precipitated by the folution Of albumen.

The precipitates by gelatine had all a pale tint of red-brown, Precipitates from
which became deeper when they were expofed to the air. The JjJ^^1 efaiine"
compound of gelatine and the tannin of the ftrongeft infufions 41 tannin and
of catechu appeared, by eftimation of the quantity of ifinglafs $9 6elatine»
in thefolutions ufed for their precipitation, to confifl of about
41 parts of tannin, and 59 of gelatine.

Of two pieces of calf-fkin which weighed, when dry, 1 32 Calf /kin (quick-
grains each, and which had been prepared for tanning, one was W tanned by

1. r j • 1 L-L c ^ ■ c r c L 1 r «techu afforded

immerled in a large quantity of the infufion or catechu from good leather.
Bengal, and the other in an equal portion of the infufion of Th.e increafeof
that from Bombay. In lefs than a month they were found con- tner left than
verted into leather. When freed from moifture, by long ex-one fifth of the
pofure in the funlhine, they were weighed. The firft piece ea er*
had gained about 34- grains ; and the fecond piece 35f grains.
The leather was of a much deeper colour than that tanned
with galls, and on the upper furface was red-brown. It was
not acted on by hot or cold water; and its apparent ftrength
was the fame as that of fimilar leather tanned in theufual man-
ner.

In examining the remainder of the infufions of catechu, in Little extractive
which Ikin had been converted into leather, I found in themmatt
much lefs extractive matter than I had reafon to expect, from
the comparative analyfis of equal portions of the unaltered in-
fufions made by folutionsof gelatine. At firft, I was inclined
to fuppofe that the deficiency arofe from the action of the aU
mofphere upon the extractive matter, by which a part of it
was rendered infoluble. But, on confidering that there had
been very little precipitation in the procefs, I was led to adopt It had in part

the fuppofition, that it had entered into union with the (kin, at ^mVintA with

. . r r . the fkin.

the fame time with the tannin ; and this fuppofition was con-
firmed by new experiments.

Bolh kinds of catechu are almofr. wholly foluble in large Water diflblves
quantities of water ; and, to form a complete folution, about 18 ""^hu^01*

Vol. V. — August. T ounces

i

274 EXPERIMENTS ON ASTRINGENT VEGETABLES.

ounces of water, at 52°, are required to 100 grains of extract
Therefiduum feldom amounts to ^ of the original weight of
the catechu ; and, in mod cafes, it is found to confift chiefly of
calcareous and aluminous earths, and*offine fand, which, by
accident or defign, had probably been mixed with the primi-
tive infufion at the time of its evaporation.
Alcohol diflolves A considerable portion of both kinds of catechu is foluble in

much ; and alcohol ; but, after the action of alcohol upon it, a fubftance
leaves mucilage. _ , . , * , . , .

remains of a gelatinous appearance and a light brown colour,

which is foluble in water, and is analogous in its properties to

gum or mucilage.
The peculiar ex- The peculiar extractive matter in the catechu, is much lefs
traft of catechu f0]ut>Ie in water than the tanning principle ; and, when a fmall

is much efs fo- . *» • r

luble than tannin quantity of water is u led to a large quantity ot catechu, the
in water. « quantity of tannin taken up, as appears from the nature of the

ftrongeft infufion, is very much greater than that of the ex-
tractive matter.
And is more fo- The extractive matter is much more foluble in warm water
y than in cold water j and when faturated folutions of catechu

are made in boiling water, a confiderable quantity of extrac-
tive matter, in its pure ftate, falls down, as the liquor becomes
cool.
Repeated lixivi- The peculiar extractive matter of the catechu may be like-
in1 water,0 leave w^e obtained, by repeatedly lixiviating the catechu, when in
the peculiar ex- fine powder, till the fluids obtained ceafe to precipitate gela-
tract. tjne . tjie ref1(jua| foiid Wl\\ then De founfi to be the fubftance

in queftion.
Its fenfible The pure extractive matter, whether procured from the

qua lties. Bombay or Bengal catechu, is pale, with a faint tinge of red-

brown. It has no perceptible fmell ; its tafte is flightly aflrin-
gent ; but it leaves in the mouth, for fome time, a fenfation of
fweetnefs, ftronger that given by the catechu itfelf.
Solution in water jts f„iuti0n in water is at firft yellow-brown; but it gains a
tint of red by expofure to the air. Its folution in alcohol does
not materially change colour in the atmofphere ; and it is of an
uniform dull brown.
Habitude with The extractive matter, whether folid or in folution, was not
tefts > found to produce any change of colour upon vegetable blues.

— with alkalis. It became of a brighter colour by the action of the alkalis ;
but it was not precipitated from its folution in water by thefe
bodies, nor by the alkaline earths.

4. The

EXPERIMENTS ON ASTRINGENT VEGETABLES. 275

The aqueous folution of it, when mixed with folutions of— -with other
nitrate of alumine and of muriate of tin, became flightly turbid.

To nitrate of lead, it gave a derffe light brown precipitate.

It was not perceptibly a6ted upon by folution of gelatine J
but, when folution of fulphate of alumine was added to the
mixture of the two fluids, a confiderable quantity of folid mat-
ter, of a light brown colour, was immediately depofited.

To the folution of oxygenated fulphate of iron, it communi-
cated a fine grafs-green tint ; and green precipitate was de-
pofited, which became black by expofure to the air.

It was not precipitated by the mineral acids.

Linen, by being boiled in the ftrongeft folution of the ex- Linen abftra&s
tractive matter, acquired a light red-brown tint. The liquor1" t,ngs*
became almoft colourlefs ; and, after this, produced very little
change in the folution of oxygenated fulphate of iron.

Raw fkin, prepared for tanning by being immerfed in the ~ as does raw
ltrong folution, foon acquired the fame kind of tint as the linen. ^Ii*
It united itfelf to a part of the extractive matter; but it was
not rendered by it infoluble in boiling water.

The folid extractive matter, when expofed to heat, foftened, The folid extract

and became darker in its colour, but did not enter intofufion. fofte"s ^ <*oe*

' not rule by heat.

At a temperature below that of ignition, it was decompounded. Deftruclive de-
The volatile produces of its decompofition were, carbonic acid, composition,
hydrocarbonate, and water holding in folution acetous acid and
a little unaltered extractive matter. There remained a light
and very porous charcoal.

In confidering the manner in which the catechu is prepared,
it would be reafonable to conclude, that different fpecimens of
that fubftance muft differ in fome meafure in their composition,
even in their pure flates ; and, for the purpofes of commerce,
they are often adulterated to a confiderable extent, with fand
and earthy matter *.

In attempting to eftimatethe compofition of the pureft cate- Component parts
chu, I felecled pieces from different fpecimens, with which I catec u*
was fupplied by theprefident, and reduced them together into
powder ; mixing, however, only thofe pieces which were from
catechu of the fame kind.

* One fpecirnen that I examined, of the terra japonica of com-
merce, furnifhed, by incineration, -J. of fand and earthy matter $ and
another fpecirnen, nearly £.

T 2 Two

276 EXPERIMENTS ON ASTRINGENT VEGETABLES.

Two hundred grains of the powder procured in this way,
from the catechu of Bombay, afforded by analyfis.

Grains.
Bombay catechu. Tann;n lQ9

Peculiar extractive matter .... 68

Mucilage - - - - - - - -13

Refidual matter ; chiefly (and and calcareous earth 10

The powder of the Bengal catechu gave, by fimilar methods
of analyfis, in 200 grains,

Grains.

bengal catechu* • Tannin .^--.-..97

Peculiar extractive matter . - - 73

Mucilage - - - - - - . - 1$

Refidual matter-; fand, with a fmall quantity of calca-
reous and aluminous earths - - - - 14

In thefolidfam- I" examining thofe parts of the catechu from Bengal which

pies the tannin Were differently coloured, I found the largeft proportion of
and mucilage are . ... . . * r 1 r ^ * 1 «

imperfectly tannin in the darken part of the lubttance ; and molt extractive

mingled. matter in the lighteft part. It is probable that the inequality of

composition in this catechu, is owing to its being evaporated
and formed without much agitation ; inconfequence of which,
the conftituent parts of it that are leaft foluble, being firft pre-
cipitated, appear in fome meafure diftincl from the more foluble
parts, which aflume the folid form at a later period of the
procefs.

Pale catechu From the obfervations of Mr. Kerr*, it would appear, that

xnoft in requeft. the pale catechu is that moil fought after in India; and it is

It contains more . . , , ... , . ;? _ .

of the extract, evidently that which contains molt extractive matter. The ex-
tractive matter feems to be the fubftance that gives to the ca-
techu the peculiar fweetnefs of tafte which follows theimpref-
lion of aftringency ; and it is probably this fweetnefs of tafte
which renders it fo agreeable to the Hindoos, for the purpofe
of chewing with the betle-nut.

(To be continued.)
* Medical Obfervations, Vol. V. page 155.

Mem

ON rmjssic ACID. 277

X.

Memoir on the Nature and the new Properties of the PrvJJic Acid.
% Cit. Curaudau, corrcfponding Member of La SocietS
libre dea Pharmaciens de Paris *,

1 HE Pruflic colouring matter has been long known in che- tXncertaintie»
miftry, but we have yet no correct knowledge of its nature t0' thTtheory"of
and different modifications ; chemifts are not even agreed as Pruflic acid,
to the formation of this lingular fubftance. Some admit that
oxigen forms a part of its compofition, and others aflert it to
be an acid without oxigen. Indeed this composition performs
the functions of an acid in many inftances ; but in certain others,
and particularly in its fimple ftate, it ceafes to exhibit the pro*
perties common to other acids. This diverfity of opinions on
a (ubftance which we can compofe and decompofe, reduce and
combine at pleafure, feems to contradict our chemical know-
ledge, and to carry us from that perfection towards which
perfett fcience ought continually to tend.

In fact, if in the clafs of acids it were proved that there Whether an
were one without oxigen; might we not conclude that thtf tffrhmt oariwm
bafes might, as well as oxigen, contain the acidifying princi-
ple, and would it not follow that we have gratuitoufly afcribed
to vital air the property of generating acid ?

It is of importance then, under ihefe circum fiances, to fix The prefent ra-
the opinions of the chemifts on this point, and to determine termine the
what may be the concurring caufes that give the pruflic co- caufes by which
louring matter the characieriftic properties of acids, or to fe- Ja"^-^"^-"6
parate it from their clafs. This is the problem which I have fied, and the
undertaken to refolve. If I have not fulfilled the talk, I dare contr317'
at leaft flatter myfelf that my observations will prove ufeful to
the prog re Hi of fcience, and that they may deferve the atten-
tion of the chemical world.

In order to avoid the continual repetition of Pruflic acid, Adjustment of
Pruffic colouring matter, &c. I (hall in future defcribe this terras#
acid under the name of " Prujjire," its combinations without
oxigen " PrvJJiurets," and its oxigenated combinations " Pruf-
fiates." This correction of Nomenclature becomes- neceflary

* From Les Annalcs de Chimie, No. 137. Vol. XL VI. p. 148-

not

278 ON PRUS.SIC ACID.

not only to fhorten the expreffions, but to explain in proper

terms fuch notions as indicate the real ftate of the fubftance

under defcription.

The gafeow Chemifts have never diftinguifhed the Pruffic acid, faturating

lefs ox'genthana metalMC fubftance from the gazeous Prvjfire, They have

when in com- always believed on the contrary that this laft, extracted from

macion. an^ pru0iate whatever, was the fame as in its ftate of combir

nation. But on a nearer examination, we find it impoffible to

obtain fimple Pruffic acid ; that it can only exift in a combined

ftate ; that its combinations can only take place by virtue of

the oxigen afforded by the bafe to which it is united : laftly,

It cannot exift that the fimple pruffire cannot exift with the pretence of oxi-

withmoreoxi- without an immediate deftru.aion of the affinity which

gen : ror this ° J

laft will acidify held its three component principles together. The carbon in
itscarbon, while ^ rac|ical js particularly difpofed to unite witli oxigen, and
the azote and . ' , r , • ,- , • ' • , ,

hydrogen form at the inftant when the iubtraction or this principle is made,
ammonia 5 and |jie azote and the hydrogen become liberated, and immediately
of ammonia will f°rm ammonia, which is alfo fafurated by the carbonic acid
be had. at the moment of their mutual production. Water is the ox-

igenated compound which has the ft rongeft effect in producing
thedecompofition of pruffire, without feparating its elements ;
that is to fay, the refult of this decompofjtion is always car*
bonic acid and ammonia.
Suppofed incon- Tlie fixity of pruffire (hewn by the high temperature at which
Utility* I or Ra-°" ** is formed, does not appear to me to agree with what is
zeous form) of already known relative to its extreme volatility, and of its little
orMnaVfixU ! " difPof'tion to unite direflly with faline bafes. I thought it ne-
ceffary to direft my enquiries to this object, in order to ascer-
tain, if poffible, the caqfe which produced fuch oppofite pro-
perties in the fame fubftance, and which, as I apprehend,
muft arife from facts not yet known and underftood.
The fixity of I could not attribute the Jixity of pruffire to the oxigen,

ih-wnb'y the &nce> by the experiments which I publifhed five years ago ^,
great heat it fup- I have (hewn that this principle always oppofes its formation,

ports during cal-an(1 even deftroys it when already formed. Thus, from the

cination does not , 1 ,

arile from oxi- moment it was proved that the calcinations intended to form

£en» the pruffire is ineffectual wherever oxigen is prefent, I could

no longer admit that this compound, when formed by calcina-
tion, with an alkali, can derive its fixity from oxigen. It be-

* Journal de Pharmacie, cahier de Germinal, An 6.

came

€>D £RUSSIC ACID. 279

came necefTary, therefore, for me to direct my enquiries ac-
cording to the indications afforded by my own experiments,
and to continue them till I (liould become acquainted with the
caufe of fixity in afubftance which immediately on its forma-
tion, poflefled properties quite oppofite to thole which it
feemed to poflefs during the action of calcination,

Perfeverance in varying my enquiries on this object, gave The calcination
/ °. . J ^ . . V affords only car-

me an opportunity of making many important oblervations,|)oaared azote

and to afcertain, by decifive experiments, that the Pruffic cal of potato. The
cination gives nothing more than the carbonated azote of Pnt- g;VenStni water
afh, and that the hydrogen which enters into the compofitior. is applied:
of the pruffire, is always the refult of a combination which
takes place fubfequent to the calcination. Hence I faw that
it was this circumftance which fo long produced the chemical
illufion, and from which we flill confound this production with
that contained in the crucible. But it is a phaenomenon wor-
thy of remark, and of which the explanation is very proper
to throw light on the nature and formation of pruffire, that the

carbonated azote of potafh pofTeffes the property of inftanily — which fluid is
, r i*i , ■ . inftmty decom-

decomponng water ; and at the moment the water is decom- pofe<j#

pofed, the pruffire is formed, together with ammonia and car-
bonic acid. Though this immediate production of three new
compounds is the refult of very complicated affinities which
are difficult to be well made out; we may neverthelefs fufpect
that the potafli, which is always found in excels in pruffic cal-
cinations, is the fubftance which in this cafe preponderates in

the affinities, and that this fubftance, by a predifpofjng a<trac-ExPla"a£°Vu
. , , , the effect of the

tion, promotes the oxigenation of the carbon at the expence affinities.
of the oxigen of the water ; the hidrogen, which being fet at
liberty by this fubtraction of oxigen, unites at the fame time
with the carbonated azote of potafh. One part of the hidro-
gen is thus employed in forming ammonia, while the other
ferves to form the pruffire, which was not pruffire for want of
the hydrogen, its third element. It is (till farther in favour of
this theory that fhe potafh in its progrefs to faturation with
carbonic acid may, by long ebullition, fucceffively convert
the greater part of the pruffire, into ammonia and carbonic
acid ; this decompofition ufually continues til! the potafh is

completely faturated with the carbonic acid. Hence it is thatTnePrufl*lc

, _ .. . . , , , yit lixivium may be

a very good pruffic lixivium may be partly decompoled by decompofed by

fimple ebullition, and that in all- pruffic calcinations, thofe water and loft

• • , incurred*
which

280 0N PRUSSIC ACID.

which are moft ftrongly heated always form lixivium faturatcd
with the carbonic acid ; this can only happen at the expence
of the oxigen of the water and the carbon of the carbonated
azote of potafh : The potafh, therefore, as I have already ob-
ferved, contributes in part, by a predifpofing attraction, to the
fucceffive developement of all thefe new combinations.

After having proved that carbonated azote of potafli inftant-
ly decompofes water, and that water alfo fucceffively decom-
pofes the pruffire ; which is always by a diminution of its
quantity ; I (hall now (hew the means which mull: be ufed to,
prevent the deftruction of this fubflance, and (hew that they
perfectly agree with the theory I have here laid down.
Remedy againft The deftructibility of pruffire of potafh being highly preju-

watertuh the"S d'cial in ,arSe °Perat5ons> l directed my refearches to the
pruflic calcined means of preventing that lofs. The refult of my obfervations
matter. jS) i\)a[) Jn order to (top this decompofition, it is an indifpen-

fable condition, never to wet a pruflic calcination but with a
Sulphate of iron foIULion of fulphate of iron at the maximum of oxigenation ;
this method is intitled to the moil decided preference; for in
this cafe the pruffire, whichis formed at the moment of the
mixture, being in a (late favourable to the faturation of pota(h,
it becomes fixed at the expence of the oxigen of the oxide of
The pruffire can \r0n} and in this date it is pruflic acid. I mull obferve that
naced byTme- tms oxigenated combination of pruffire cannot lake place but
tallic oxide. by the concurrence of metallic fubllances already oxigenated ;
and that it is only then that an equilibrium of affinities is efta-
blifhed between the potafli, the pruffire, and the metallic
oxide ; which produces a complex and energetive combination,
that I propofe to call pruffiate of potafli by the oxide of iron;
which method of nomenclature I propofe to apply to each fe-
veral metallic oxide which enters into the compofition of pruf.
iiate of potafli. All thefe combinations cryftallize eafily by
evaporation, and by cooling the lixivium we may obtain very
regularly formed cryftals.
Inference. The confequences we fhould naturally draw from thefe latter

obfervations (hew therefore irrevocably that the pruffire owes
its acid or neutralifing property to the oxigen of the oxide of
iron, and that as the quantity of water decompofed in this cafe
does not exceed what is neceflary to fupply the hydrogen in
the pruffire, we mud accordingly obtain more abundant pro»
ducts than in any other cafe.

I may

ON FRUSS1C ACID-. £>$ \

I may obferve, in fupport of what I have here advanced, Berthollet tirft
that M. Berthollet, whofe fagacity is well known, has proved, pru{fic gas con_
more than fifteen years ago, by a very accurate analyfis, that ttias no oxigcn.
what was called the pruflic acid, does not contain oxigen. It
is true indeed, that there are many chemifts no lefs celebrated,
who have not coincided in this opinion, and have coniidered
what M. Berthollet had advanced as very far from complete
proof. I mud, neverthelefs, infill that the labours which that
learned chemifi: has made known on this object, are a prelude,
in fome fort, to the difcoveries which remained to be made,
in order to complete the hiftory of the properties of the pruflic
acid.

It remains then very evidently demonftrated from thefe re- The theory is
fults, as well as thofe obtained by M. Berthollet, how far this [he^efukTbe^
theory is fatisfaclory, and how much it enables us to explain neficial.
facts, reflecting which we have hitherto had no very correct
notions. Laiily, from all thefe new applications, we mav,
with a knowledge of the caufes, fabricate in the large way,
cryflals of pruffiate of potafh, by oxide of iron. It is now a
confiderable time fince I firft prepared fimilar cryftals, but
without being able to eftablifh a theory fufficiently clear to be
communicated.

It is to be remarked that Pruffian blue obtained with the The Prufiian
pruffiate of potafh by the oxide of iron, gives a blue of the moft blue f eatly im"
exquifite beauty. Its interior fracture is fmooth and of a cop-
perifh hue, fimilar to that (een in indigo of the beft quality.
An obfervalion which equally deferves mention is, that the
pruffiate of potafh by oxide of iron has the property of form-
ing with a hot folution of fulphate of alumine, a magma ana-
logous to that of boiled fecula. If the mixture be diluted with Prirfliate of
water to favour the feparation of the precipitate it is then of aIumine*
a iky blue colour. This precipitate vvafhed and dried becomes
of a deep blue, approaching to black; its fracture is fmooth
and has a refinous appearance ; it is the pruffiate of alumine
by the oxide of iron.

Recapitulation.
It reful ts from all that has been here faid : Recapitulation

1 . That the pruffic calcination contains but two of the ele- i. Pruffic cal-
ments of pruffire, azote and carbon: and that the third ele- C1"at'0n glve3

~ i r • r> i ., . n only azote and

ment neceflary to the composition or the acid, is the refult of carbon along
a combination formed after the calcination. with rfie alka1'*

2. That

282

2. which is a
new compound,

3. capable of
inftantly decora
pofing water.

4. propofed
nomenclature
of its com-

pounds

5. water de-
compofes prufli
uret and occa-
fions Ms,

6. Which may
be prevented by
tifing fulphate
of iron,

7. the pruftic
acid gas is a
mere radical,
which acquires
its acid proper-
ties by oxigen
from an oxide.

ON PRUSSIC ACID

2. That the carbonated azote of potato is a new compound
in chemiftry, from oar acquaintance with which we may fuc-
ceed in decompofitions which have hitherto been attempted
without fuccefs.

3. That the properly which carbonated azote of potato has
of inftantly decompofing water produces the prufficacid, and
that it is the potato particularly which affifts the oxigination of
the carbon and the combination of the hydrogen with the azote
and the carbon.

4. That we muft now call the fuppofed pruffic acid by the
name of pruffire, becaufe its properties are analogous to thofe
of all the radicals. Its combinations without oxigen will be
called prufliurets, and thofe which are oxiginated, pruffiates;
with refpeft to the latter, when they are not directly combined
with a metallic fubftance, it will be neceflary to mention along
with the direct bafe, the metallic oxide which may have given
them the properties common to the acids. For example, the
combination of pruffire with potato will be called pruffiuret of
potato ; with oxide of iron, prufliate of iron, and with potato
and oxide of iron, prufliate of potato by oxide of iron. With
refpedt to thofe metallic pruffiates which are capable of pafling
fucceflively into different degrees of oxigenation they may be
defcribed by their colour, which will fufficiently indicate the
ftate of the prufliate.

5. That the continued aftion of water upon the pruffiuret of
' potato is able to change it completely into carbonic acid and

ammonia. This muft fhew that the hydrogen in the pruffire is
not combined with the azote in the proportion neceflary to the
compofition of ammonia, and that it muft be by the lofs of hy-
drogen in the water that the pruffire pafles fucceflively into the
ammonial ftate.

6. That the decompofition of part of the pruffire may be
prevented, by never moiftening a pruffic calcination, but with
a folution of fulphate of iron at the maximum of oxigination.

7. Laftly : What is called pruffic acid gas, is not an acid,
but only the pruffic radical, and that it acquires the acid or
neutralizing property only by means of the oxigen which is
imparted to it by a metallic oxide, of which the concurrence
is neceflary to form with the faline bafis a ftrong and durable
compound.

Defcrip*

DESCRIPTION OF THE SUBTERRANEOUS GRAPHOMETER. gg5

XI.

Description of the Subterraneous Graphometer invented by M.
Komarzewski, F. R. S. and prefented to the National Injli-
Jiitute of France *.

A HIS inftrument is a fimple conftru&ion of the common Defcription of;
theodilite, and is calculated to anfwer the author's intention 1^1™"^*
in operations like thofe of mining, where great accuracy is not
required.

The rougheft kind of furveys are made by taking angles
with the compafs,, and thefe are itill ufed in mines, and in the
diftricls of unfettled countries. Our author has taken the next
procefs, and obtains confiderably more accuracy, without de-
viating from fimplicity and cheapnefs.

This fubterraneous graphometer is compofed of three prin-
cipal parts, viz* a circular horizontal plate, a circular vertical
plate, and a pedeftal, which are refpeclively reprefented in
perfpedive, (Figs. 2, 3 and 5, Plate XV.)

The horizontal Plate A. Fig. 2. is divided into 360° doubly-
numbered, the fubdivifions are carried to 15', this is confidered
fufficient for mines where there is feldom light enough to ob-
ferve a more minute divifion : for operations on the furface of
the earth a Vernier's fcale may be added.

Within the line of divifions above mentioned, is that of the
magnetic compafs : which gives the reduction of hours into
degrees, and that of degrees into hours.

This plate meafures the horizontal angles which the miners
call the direction.

Through its centre pafles the cylinder a, on which turns the
hollow cylinder, which forms the centre of the horizontal index
bb, and carries the vertical plate B, as reprefented in Fig. 1.

The horizontal index is one inch in breadth, and is increafed
at the centre by two circular fegments cc call with it, in
order to give the vertical plate a more firm bearing on the
horizontal plate at the top of the cylinder a, a fcrew a is in-
ferted to confine the cylinder.

* From a folio publication in Engli/h, entitled, Memoir on a
Subterraneous Graphometer, &c. published at Paris by Pougens,
1803.

The

284 DESCRIPTION OF THE SUBTERRANEOUS GRAFHOMETER.

Defcriptionof a The hook attached to one extremity of the horizontal index

fubterraneous is intended for the fufpenfion of a plumb line,
graphometer. . J* '„ ; r .

The vertical plate B, Fig. 3, is only fix inches in diameter,

in order that the extremities of the horizontal index may be

left perfectly clear.

Two indexes d d, are moveable round its centre c, which
meafure the angles of inclination. They are fomewhat nar-
rower than the horizontal index. Their extremities are like-
wife furnifhed with threads to mark the quantity of the angles
to the extremities of thefe indexes, and in the direction of their
axes are fixed two hooks in order to receive the cords which
put the indexes in motion.

The vertical plate is divided on each fide by two lines paf-
fing through its centre, one of which is horizontal and the
other vertical, the one mark the diameter, and the other the
radius. The upper part of the plate is likewife divided on
each fide into twice 90. This divifion commences at the hori-
zontal diameter, and proceeds to the vertical radius, the lower
part which is but a fegment of the circle, contains only on each
fide 30°, this is fufficient for a lode or gallery in mines, more
confiderable inclinations being meafured like the depth of a
fhaft.

Thefe two plates with their indexes form the graphometer,
the other parts belong to the pedeftal, on which it may be
moved as occafion requires. Its dimenfions depend upon the
v fpace in which the graphometer is to be employed. The pe-
deftal is represented at Fig. 5, as follows,

A board EE about 18 inches long, fix inches wide, and one
in thicknefs, receives in a focket made its centre, the brafs ball
K, furmounted by the cylinder H cafi: with the ball, the board
is bored towards its extremities, to receive brafs fcrews, by
which it is fixed on fome wooden bar in the mines.

The ball K is covered by a fquare plate g, which is concave
and perforated in its centre, and is fixed to the board E by the
four fcrews h: it is by loofening or tightening them that the
graphometer is fixed or levelled.

On the cylinder H turns the hollow cylinder F, which is
caft with the fmall plate D, this hollow cylinder is furnithed
with a tightening fcrew G, to fix the graphometer when placed
upon the plate D : the graphometer is fixed to this plate by two

ilaples

DESCRIPTION OF THE SUBTERRANEOUS GRAPHOMETER. 285

ftaples//foldered to the horizontal plate A, which enter two Defcription of a

fubterraneoui
graphometer.

correfponding holes in the plate D, and are confined by the fubterrai

bolts //Aiding in grooves foldered beneath the fame plate.

In the centre of the plate D as well as in the centre of the
inferior part of the ball K, is a female fcrew it to receive
the folid cylinder L, Fig. 4, the ufe of which will be feen in
the folution of the problems. This cylinder is furnifhed with
a moveable collar m, having a hook in its centre, to which the
other extremity of the cord may be attached.

Fig. 1 . is a perfpettive view of the graphometer, in which
A is the horizontal plate, B the vertical plate, a a the centre
of the vertical plate, &c. b b the horizontal index, d d the
vertical indexes.

From this difpofition it refults that, when one direction is
known, which for the firft operation may be determined by
the magnetic compafs, or in mining ftill better by a meridian
line pafling through one of the principal (hafts, the inftrument
may with facility be directed to any given point, and all plans
be executed which are neceflary in operations of mining, with-
out making ufe of the magnetic needle, and that the direc-
tions and inclinations may be taken at the fame time, fince in
all thefe operations it is only neceflary to obferve the angles
indicated by the inftrument, to meafure the length of the line,
and to calculate right angled triangles, of which three parts
are known.

The pedeltal is intended to be placed at the point of the
angle fought, and the cords flretched to it from the grapho-
meter, the cord is fixed to the hook of the graphometer by a
noofe, and its other extremity to the cylinder L of the pedeftal,
by means of the fcale and pin reprefented at Fig. 6.

Experiments

286 EXPERIMENTS ON VARIOUS ALLOYS OF GOLI>,

XII.

Experhnents and Obfcrvations on the various Alloys, on the Specific
Gravity, and on the comparative Wear of Gold, Abftracled
from the Memoir of Charles Hatchett, Esq.. F. R. S *.

INTRODUCTION.

Appointment of J. HE Lords of the Committee of his Majefty's mofl honour-
Ef ^nTc^Hat- able ^"*J Counci,» appointed by his Majefty, on the 10th of
chettEfq. to February, 1798, to take into confederation the Hate of the

malceexpen- coins of this kingdom, having among other circum fiances re-
nientsonthe . ■■ ■' ? , . , , r . • . , , i i

wear of gold} marked the confiderable lots which the gold coin appeared to

have fuftained by wear within certain periods, and being de-
firous to afcertain whether this lofs was occafioned by any
defect, either in the quality of the ftandard gold or in the figure
or impreffion of the coins, were pleafed to requeft that Henry
Cavendifh, Efq. F. R. S. and the author of the prefent me-
moir would examine, by fuch experiments as fhould be deemed
requifite, whether any of thefe defects really exifted.
Two queftions were to be principally decided,
different m ift. Whether very foft and ductile gold, or gold made as

compo tionj j^^ ^ .^ com^'1\)\e wjtjj t}ie procefs 0f coining, fuffers the

mod by wear, under the various circumftances of friclion to
which coin is fubje&ed in the courfe of circulation ?

or in figure. 2dly. Whether coin with a flat, fmooth, and broad furface,

wears lefs than coin which has certain protuberant parts raifed
above the ground or general level of the pieces ?

Therefearch Is The great value of the material, had hitherto prevented pri-
vate individuals from ascertaining thefe facts by experiment .
and, as a public concern ; this fubjeci of invefligation, al-
though fo important to political economy and to fcience, does
not appear to have been noticed by any European government,
until the Right Honourable and enlightened Members of the
above-mentioned Committee propofed the inquiry, and furnifii-
ed the requifite means for making the experiments +.

mew

* In the Philofophical Tranfaftions for 1803.
f Thefe experiments were begun in the latter end of 1798, and
were completed in April, 1801.

SECTION I,

EXPERIMENTS ON VARIOUS ALLOYS OF GOLD. 287

SECTION I.

ON THE VARIOU3 ALLOYS OF GOLD.

The wear of coin is fubject to be modified by certain phyfical Plan of cxpcri-
properties, fuch as ductility and hardnefs, which vary in de-
gree, according to the chemical effects produced by different
metallic fubftances, when employed in certain proportions as
alloys. From thefe confiderations, it appears proper,

Firft, to examine the effects which the various metals pro- Effects of alloys,
duce upon gold, when combined with it in given proportions,
beginning with T\f, which is the ftandard proportion of alloy,
and in certain cafes gradually decreafing to J of a grain in the
ounce of troy, or tj^ part of the mafs.

Secondly, to examine the fpecific gravity of gold d if- Specific gra-
ferently alloyed, and the caufes of certain variations to which vm""
it is liable.

And, thirdly, to afcertain the effects of friction varioufly Wear.
modified.

GOLD ALLOYED WITH ARSENIC.

Experiment I.
To 5307 grains of gold in fufion, 453 pure arfenic were Gold and
added. Only fix grains remained in the ingot, which was ar cmc*
brittle.

Experiment II.
To 442 grs. gold were added 19 grs. copper, and on perfect Gold, copper,
fufion, 19 grs. pure arfenic, and the whole quickly poured an aremc*
out. None of the arfenic remained.
Experiment III.
480 grains of gold in a fmall crucible was inclofed within Gold and arfe-
two larger crucibles, well luted together. 480 grains of pure ™cff^ c,ofe
arfenic were included in the outer veffel. Strong and con-
tinued heat, (a) raifed fome arfenic in the white oxide, (b)
and alfo a final I portion of the gold, (c) and the gold was
brittle, with a coarfe gray fracture, an increafe of 1,5 grains
in weight, (d) It was difficult to expeli the arfenic by heat.
Experiment IV.
A plate of gold was fufpended within two crucibles ground Gold expofed to
and luted together, pure arfenjc being placed in the lower. Jfenfcat ^rei

By heat.

258 EXPERIMENTS ON VARIOUS ALLOYS OF GOLtf,

By a full red heat, the arfenic rofe and combined with the
furface of the plate, producing a very fufible compound,
which ran down into the lower veflfel. The plate, which had
been ^ of an inch thick, was become as thin as paper ; but
was flilj pure gold. The fufed compound was extremely
brittle, and gray within. It contained a very large quantity o£
arfenic, but how much is not ftated.
Experiment V.
Variation of Variation of the preceding experiment. The arfenic was

fc*P« 4* introduced through a hole after the ignition, and the heat not

kept up. The furface of the plate was impregnated with
arfenic ; but the heat not being fufficient to caufe it to flow
down, it adhered to the plate, and rendered it lefs flexible.

GOLD ALLOYED WITH ANTIMONY,

Experiment I. to VIII.
Gold and anti- Golds in various proportions and of different finenefs were
mony. combined with pure antimony by heat. Small proportions of

the latter, produced a pale, dull, unmetallic colour, and
rendered the compound exceedingly brittle. Minute quan-
tities ftill impaired the metallic brilliancy, and caufed brittle-
nefs. Lefs than one quarter of a grain, in the ounce of gold,
were fuflicient to produce thefe effecls. The vapors of antimony
readily combine with gold in open as well as clofe veffels, and
afford the fame changes.

GOLD ALLOYED WITH ZINC.

Experiment I. to VI.

Cold and einc By tne^e experiments, it was (hewn, that zinc is highly in-
jurious to the ductility of gold ; that a portion of it is eafily
feparated from gold by heat ; that, when a large quantity of
gold is alloyed with the flandard proportion of zinc, only part
of the latter is fpeedily volatilized, but, when fmall quantities
are treated, the whole of the zinc becomes feparated, and the
gold remains pure; that, if zinc is previoufly combined with
copper in the ftate of brafs, it is not fo eafily feparated by heat,
when added to melted gold ; and, laftly, that gold in fufion
abforbs and retains a portion of zinc, when expofed to the latter
metal in a volatilized (late, even in open veffels.

GOLD

5

EXPERIMENTS ON VARIOUS ALLOYS OP GOLD. 239

GOLD ALLOYBD WITH COBALT.

Experiment I. to IV.
This addition debafed the colour of the gold, and rendered GoId *nd cobalt,
ft brittle. When to an alloy of about 10 parts gold, and 1
part copper, nearly half a quarter part of cobalt were added,
the metal began to be ductile.

GOLD ALLOYED WITH NICKEL.

Experiment I. to IV.
The colour and dudility of gold were injured by nickel, Gold and *Ml
but lefs than by any other of the brittle metals. When to
about eleven parts of gold, and one of copper, one fourth
of a part of nickel was added, the compound was fcarcely
brittle.

GOLD ALLOYED WITH MANGANESE.

Experiment I. to III.
The black oxide of manganefe ftrongly heated with gold GoM *n(1 roan-
did not affect it. But when olive oil had been previoufly
burned on the oxide, this powder ftrongly and permanently
heated with gold, rendered it pale and brittle. This alloy is
lefs fulible than pure gold ; it does not change by long ex-
pofure to the air; and the manganefe is defended from the
ufual action of acids. It may be leparated by cupellation, or
better by quartation and nitric acid.

GOLD ALLOYED WITH BISMUTH.

Experiment I. to VI.
Bifmuth added to pure, or to alloyed gold, is exceedingly Gold and bif-
injurious to its colour and ductility. It produces thefe effects m
when the quantity is no more than -^Vs part of the mafs; and
the combination takes place by the vapor of bifmuth, in open
as well as clofe veffels.

GOLD ALLOYED WITH LE AD.

Experiment I. to IX.

Lead is nearly as injurious to gold as bifmuth ; one quarter Gold and lead,
of a grain in the ounce producing complete brittlenefs. Its
vapor in clofe veffels greatly contaminates gold, but in open
veffels the effect was inconfiderable.

Vol. VI. — August, U goljb

2C)Q EXPERIMENTS ON VARIOUS ALLOYS OF GOLB,

GOLD ALLOYED WITH TIN.

Experiment I. to IV.
Gold and tin. A confiderable portion, as -^ of tin rendered gold paler and
lefs ductile : frnall quantities as 7^ did not material injure it.
Mr. Bingley, in confequence of Tillet's experiments, related
in the Acad. Par. 1790, and in the Quarto Series of our
Journal II. 140, 179, made experiments on an alloy of gold
and tin, containing eight grains in the ounce of the latter
metal. The fa&s are, 1. the earlier chemifts, probably as
Mr. Hatchett obferves, milled by a tin containing bifmuth,
lead, antimony or zinc, did affirm that the fmalleft portion
of that metal renders gold brittle ; 2. Mr. Alchorne mewed
the fallacy of that general pofition, by experiments on fuch
alloys. 3. Mr. Tillet (hewed that tho* gold alloyed with tin,
may be hammered and laminated cold, yet it falls to pieces
by the annealing heat, or cherry red ; and laftly, Mr. Bingley
iinds that an annealing by five degrees of Wedgwood's pyrome-
ter, or red vifible by day light, does not render the gold unfit
for working ; but that the cherry red or1 ten degrees blifters
the furface, warps the bar, and caufes it to fall in pieces, by
the fufion of the molt fufible metal ; a general property on
which the procefs of eliquation depends.

GOLD ALLOYED WITH IRON.

Experiment* I. to IV.
Gold a»d iron. Gold, with and without copper, was alloyed with about ■—•
part of iron, and in other experiments of call iron, caft fteel, and
iron wire, gave a metal of a pale yellowifh gray, approach-
ing to a dull white, which was very ductile and laminable,
and was damped with great eafe without annealing ; though
it was harder than gold.

EXPERIMENTS ON EMERY AND GOLD.

Emery a»d Gold was heated ftrongly, and for a long time, with emery

g°id; in fine powder, and in fome trials previoully heated with oil.

No change was produced.

GOLD ALLOYED WITH PLATINA.

Gold and pla- Fine gold, and alfo ftandard gold, were alloyed with pla-

ti*1** tina. The compound was yellow jili-while, and very ductile.

3 It

EXPERIMENTS ON VARIOUS ALLOYS OF GOLD, 291-

lt was not thought neceffary to extend the experiments, be-
caufe thefe metals have been much examined by other
chemifts *.

GOLD ALLOYED WITH COPPER.

From many experiments it appears, that the varieties °f ^^'ndsdr*
copper, in commerce, although fimilar in afpect, and other copper render
obvious properties, are far from being uniform in quality; fo. gold brittle. x
that many of them are by no means fufficiently pure to be
employed as an alloy for gold ; but render it brittle.

And the different effects produced by the moulds of iron
and thofe of fand, are fuch as fully prove, that copper which
is not perfectly pure, and which has a tendency to render gold
brittle, ads more powerfully, in this refpect, when the al-
loyed mafs is caft in fand than when it is caft in iron ; and, all
things being conlidered, there is reafon to conclude, that
moulds of iron are much to be preferred to thofe of fand f.

The ores of antimony and of lead frequently accompany "" m0^ Pr0"
thofe of copper ; and it has already been proved, that T^- of timo^y^lcad,
either of the former metals is fufficient to deftroy the ductility
of gold. It may therefore be fufpected, that the brittle quality
which certain kinds of copper communicate to gold, proceeds
from thofe metals ; for, though other metallic fubftances produce
the fame effect, yet, as the former efpecially are fo commonly
prefent with the ores of copper, it is highly probable that
antimony, or lead, may remain combined with the fmelted
copper, in a proportion too fmall to afiect the general and
more obvious properties of that metal, yet ftili fufficient to
deflroy the ductility of gold, when fuch copper is employed
as an alloy.

To afcertain how far copper might be alloyed with lead, or Copper may con-
antimony, without any very apparent change in its obvious p^ion of lead
properties, the following experiments were made : or antimony,

and be very
* Gold made ftandard by platina, is not only very ductile, but merchantable,
alfo (when hammered) tolerably elaftic. perhaps it might be ad-
vantageoufly employed for the fprings of watches, Sec. C. H.

f Bars of alloyed gold (particularly thofe which are alloyed
with copper) are generally difcoloured on the furface, when caft in
moulds of fand ; but not fo when caft in iron. It may be fufpected,
that the alloy is fuperficially oxidized when fand is employed, in
confequence of the air which is lodged in the interftices, together,
perhaps, with feme degree of moifture. C. H«

U 2 To

£92 1XPERIMENTJ ON VAfclOUS ALLOYS OP GOLD.

To 476 grains of fine malleable copper, in fufion, four
grains of antimony were added, and, being well mixed, the
whole was poured into a mould.

The colour of this copper, when filed and poliftied, was
fuch as not eafily to be diftinguifhed from that which had not
been thus alloyed.

It wasalfo hammered and rolled, without (hewing any figns
of brittlenefs. The fpecific gravity was 8,354 *.

The like quantity of copper was alloyed with four grains of
lead.

This alfo was ductile, and did not fufFer any apparent
change of colour.

The fpecific gravity was 8,472.

The fame experiment was repeated with four grains of bif-
muth ; but the copper thus alloyed was exceedingly fpongy
and brittle.

It appears, therefore, that four grains of antimony, or of
lead, may be prefent in one ounce, or 480 grains of copper,
without producing any very apparent change in colour or
ductility, and but little in fpecific gravity ; fuch copper may,
therefore, without fufpicion, be occafionally employed to alloy-
gold; then, however, the antimony or lead will produce a
powerful effect ; for it has been proved, that -j-^Ve of either of
thefe will deftroy the duclility of gold. But, fuppofing one
ounce troy of copper which contains four grains of antimony,
or of lead, to be employed to alloy eleven ounces of gold,
24 carats fine, there would then be four grains of the above-
mentioned metals in the 12 ounces or troy pound ; and there-
fore the quantity of thefe would be confiderably more than is
required to deftroy the ductility of gold. For the troy pound
contains 5760 grains; and 4 is to 5760 as 1 to 1440; con-
sequently, this proportion much exceeds the quantity which is
capable of producing the above-mentioned effect,
It often contains gut the copper of commerce often contains a much greater
ablcproportion." proportion of one or other of thefe metals ; and, although it
then appears more pale than common, yet it has, without
fufpicion, been purchafed by thofe who, from their profeflion,
are fuppofed to be competent judges, and who efpecially

* The fineft Swedifli copper was employed in thefe experiments j
the fpecific gravity of it was 8,895.

2 require

EXPERIMENTS ON VARIOUS ALLOYS OF GOLD. 293

require copper to be as pure as poffible. Perfons of this de-
fcription, however, are liable to be deceived; for, in 1791,
Mr. Roitier, Director of the Mint at Paris, purchafeda quan-
tity of copper from the mines of Poullaoen in Britany ; but he
foon difcovered, from the effects which it produced, when em-
ployed as an alloy, that it was not pure, and therefore request-
ed Mr. Sage to examine it. By the latter, it was anatyfed,
and was found to contain one forty-eighth of antimony *.

Allowing, therefore, that other metallic fubftances may at Antimony is
times be prefent in copper, and may contribute to affect gold JjJ° noxwus ad»
which is alloyed with it, yet, for the reafons above related, dition.
the author is inclined to attribute, mod frequently, this effect
to antimony or lead.

Copper which is pure, is uniform in its effect, and does not
injure the duclility of gold ; it would therefore be proper in all
cafes when copper is to be purchafed for the purpofe of alloy-
ing gold, to make a previous trial of it on a fmall quantity, as
this would anfwer every purpofe of a tedious and expenfive
analyfis.

Since the above was written, he made various experi- Farther exam!,
ments in the humid way, on the d ifferent kinds of copper, JJ^SljH?*
which are known in commerce, efpecially on the following:

No. 1. Fineft granulated Swedifti copper fp. grav. 8,895.

2. Swedith dollar copper - fp. grav. 8,799.

3. fheet Britifti copper - - fp. grav. 8,785.

4. Fine granulated Britifti copper - fp. grav. 8,607.
480 grains of the firft, only afforded a few particles of ful-

phate of lead, which could not be eftimated.

The fecond contained both lead and antimony, of which the
lead was in the largeft proportion, as it amounted to nearly one
grain of metallic lead, whilft the antimony did not exceed half
a grain.

The meet Britifti copper yielded fome lead, with fcarcely
any antimony; and, on the contrary, the granulated Britith
copper contained antimony with but very little lead. We may
therefore conclude, that the varieties of copper known in com-
merce, are feldom, if ever, abfolutely free from lead or anti-
mony ; and that the brittle quality, fo frequently communicated
to gold by an alloy of copper, arifes from the pretence of one

* Journal di Pbjfiqu*> H92, Tome XL. p. 273.

or

294? EXPERIMENTS QX VARIOUS ALLOYS OF GOLD.

or both of thefe metals, which, even in the proportion of tffs
part of the mafs, was already proved to be capable of de-
ftroying the ductility of gold.
Faffs refpeft'ng Mr. H. lately made fome farther inquiries concerning the va-
Swedi copper. r|etjes Qr Swedifli copper, and was informed, that the fine gra-
nulated copper is made in this country from the Swedim cake-
copper, merely by the ordinary procefs of ganulation; and, as
the quality even of this copper has been found variable, the
Deputy Mafter of the Mint has of late employed Britiih cop-
per, which has been refined exprefsly for the purpofe, and feems
to anfwer perfectly well. Reflecting the variable and occa-
iional very bad quality of the copper dollars, Mr. Swedenftierna,
a learned Swedith gentleman at prefent in London, has fa-
voured him with fome particulars, in a letter, of which the fol-
lowing is an extract*.
Copper dollars. " But with regard to dollars, I fliould be much furprifed if
they had ever been perfectly pure ; becaufe, as far as 1 know,
they have always been made of the copper of Fahlun, of
which the ores have always been more or lefs mixed with ful-
phurated lead, and perhaps antimony. However, as thefe
dollars were originally ftruck under the Reign of Frederic king
of Sweden, and it is p^ffible that the ores at Fahlun might have
been then purer, it is probable that thefe dollars may have been
purer at firft than thofe whicli have (ince been counterfeited;
for thefe dollars having been called for in India, and ordered
more particularly in confiderable quantity, by the Aliatic Com-
pany of Copenhagen, others have been ftruck lince repeated-
ly, and of all kinds of copper without diftinction. This fact,
at leaft, explains the caufe of their inequality of compofition."
" It remains to be thewn whether any of thefe dollars are
perfectly pure. For my part, I am mod inclined to think, that
the demand in India has arifen from the convenience of form,
and that prejudice has given them credit and circulation as
money. For feveral years of late, the Danes, having found
this copper too dear, have themfelves counterfeited the mark,
and ftruck them at Rocraas in Norway; and this muft afford
another variety of this copper."

♦ The Extract is in French, of which I give the tranflation. W. N.

GOLD

EXPERIMENTS ON VARIOUS ALLOYS OF GOLD. 295'

GOLD ALLOYED WITH SILVER.

-Gold alloyed with pure filver, in ftandard proportion, is fo Gold and Giver.
generally known, that it would be needlefs here to fay more,
than that it approaches the neareft to the ductility of fine gold,
and that the fpecific gravity of this mixture differs but very
little from that which, according to calculation, would refult
from the relative proportions of the two metals.

From the foregoing experiments it is evident, that many of General remarks
the metallic fubftances with which gold may be alloyed, areon alloys of gold*
more or lefs liable to be feparated from it during fufion, in
confequence of their relative affinities with caloric, with oxygen,
or with both ; and that thefe affinities become modified, by thofe
which prevail between the various metallic fubftances and gold.
Moreover, it is evident, that even the molt oxidable metals
have this property much.diminimed or checked by being united
with gold, which appears fo to envelope and retain their parti-
cles, as to impede the ufual influence of heat, as well as the
natural exertion of their affinities with the oxigen of the at-
mofphere. The following experiment was therefore made, to
afcertain the comparative lofs caufed by the volatilization, or
by theoxidizeraent of various metallic fubftances, when added
to gold during a given period of fufion, and under fimilar cirr
cumftances.

Experiment.

Ten four-inch crucibles, which had been previoufly made Experiment on
red-hot, were put into as many twelve-inch crucibles, which 5kejj£sky^e*t-
were placed in wind furnaces of fimilar conftruclion, and heat- ent alloys.
ed as equally as poffible. Each of the fmall crucibles contain^
ed five ounces ten pennyweights and fourteen grains of gold,
%:3 car. 3| grs. fine, which being completely melted, nine pen-
nyweights and ten grains of the feveral metals were added,
and mixed in the ufual manner, after which, the fufion was
continued in the open vefTels during one hour

The different maffes, when cold, were weighed^ but, pre-
vious to this, the fcoria or glafs which had been formed on
fome of them was gently removed.

It appears, that fine gold, gold alloyed with filver, gold al- Refults of loft
loyed with copper, and gold alloyed with tin, did not fuffer b? ftronS heat#
any lofs during the experiment.

More*

296 EXPERIMENTS ON VARIOUS ALLOYS OF GOLD.

Moreover, that gold alloyed with lead only loft three grains>
chiefly by vitrification.

That gold alloyed with iron loft 12 grains, which formed
fcoria.

That gold alloyed with bifmuth alfo loft 12 grains chiefly by
vitrification.

That gold alloyed wilh antimony loft the fame quantity,
partly by volatilization, and partly by vitrification.

That gold alloyed with zinc loft one pennyweight, by vola-
tilization. And,

That gold alloyed with arfenic, not only loft the whole
quantity of alloy, but alfo two grains of the gold, which were
carried off in confequence of the rapid volatilization of the
arfenic.

Lewis, (Phil. Comm. of Arts, p. 88,) however, aflertsthat
* gold is more volatilized by antimony than by arfenic or zinc ;
•1 but to produce this effect the fire muft be vehement, the
H crucible (hallow, and the air ftrongly impelled." Thefecir-
cumftances, according to their variations, muft undoubtedly
» very much influence the refults of fuch experiments ; and

therefore, although the reverfe was found to take place in the
experiments here ftated, it does not follow that certain changes
Ihould not be produced by different degrees of heat, by the
figure of the veffels, and by a current of air more or lefs ftrong.
Silver and cop- The wno^e of the experiments of this fection tend to prove,
per only are fit that (agreeably to general practice and opinion) only two of
for the alloy of ^ metals are proper for the alloy of gold coin, namely, filver
and copper ; as all the others either confiderably alter the co?
lour, or diminith the ductility of gold. In refpect to the latter
quality, the different metallic fubftances which have been em-
ployed in the prefent experiments, appear to affect gold nearly
in the following decreafing order.
Order of efTeft J# BifmUth. 2. Lead. 3. Antimony. (Thefe are nearly
equal in effect.) 4. Arfenic. 5. Zinc. 6. Cobalt. 7. Man-
ganefe. 8. Nickel. 9. Tin. 10. Iron. U. Platina*.
12. Copper. 13. Silver.

* Had the platina been quite pure, the compound metal would
probably have poffeffed more du&ilityj I cannot therefore take upon
me to aflert pofitively, that the place here affigned to platina, is pre*
cifely that which it ought to occupy.

SECTION

EXPERIMENTS ON VARIOUS ALLOYS OF GOLD. QQf

SECTION III.*

ON THE COMPARATIVE WEAR OF GOLD, WHEN ALLOYED
BY VARIOUS METALS.

Gold, when in the form of coin, appears to be generally ex- Nature of the
pofed to three varieties of friflion, viz. Sffipi is

I ft. Fri&ion between pieces of gold coin of a fimilar or of e*pofed
a different quality.

2d. Friclion of gold coin againft coin of other metals, fuch
as filver and copper.

3d. The friction which gold coins of various qualities fuffer,
when expofed to the action of certain fubftances, fuch as the *
particles or filings of metals, gritty powders, &c.

The confideration of thefe. different modes of wear, points
out the bed method to be purfued in an experimental invefti-
gation.

The whole of the experiments which compofe this feclion
may therefore be divided into three fubordinate feries ; the two
firft of which have been directed to the confideration of that
part of the diminution of the coin which arifes from the rub-
bing of one piece of metal againft another ; while,

The third of thefe fubordinate feries was intended to (how
the comparative power of gold, differently alloyed, to refift
abrafion from fand or other gritty powders.

In the firft fet of experiments, 28 pieces of coin were fixed Defcrtptlon of
to a frame, and over each of them was placed another piece of ^f exPe.r,™entst
coin, which was preffed againft it by a weight. 'Thefe upper coin, fingly
pieces were all attached to a fecond frame, fo that, by means
of the motion communicated thereto by cranks, each upper
piece was made to move about -J of* an inch backwards and for-
wards on the lower one. This mode of experiment afforded
an opportunity of trying the comparative diminution of gold
differently alloyed; both when rubbed againft pieces of (he fame
and* of a different alloy ; and alfo of examining the difference
of wear between pieces with plain and with ftamped faces.

* The fails detailed in this important memoir having extended
my abridgement beyond my full eftimate, I find myfeif under the
nectffity either of tranlpofing the 2d and 3d fe&ions on the Specific
Gravity and the comparative Wear of Cold, or elfe of iepai ating
Plate XIV. from its defcriptioij.

In

2()8 EXPERIMENTS ON VARIOUS ALLOYS OF COLD,'

many pieces in a In the fecond feries, 200 pieces of gold, differently alloyed,
box* were inclofed in a wooden box, of a cubic figure, which was

kept conftantly turning round, till, by the repeated rubbing
and ftriking of the pieces againft each other, and againft the
iides of the box, they were found to be fenfibly diminished.
This, like the experiments of the firft fet, was intended to
fhow the comparative diminution of gold differently alloyed j
1 but, whereas that (hewed the effect of rubbing only, this
fhewed the joint effect of rubbing and ftriking, and was in-
tended to imitate (although in a more violent degree) the ef-
fect produced upon coin by pouring it out of one bag or
drawer into another.
Coin rubbed on a The experiments of the third fet were made by preffing the
flat furface. pieces to be examined againft the rim of a flat horizontal wheel,
by means of equal weights, fo that, by turning the wheel round,
they all fuffered an equal degree of friction. That part of the
wheel againft which the pieces rubbed, was fprinkled or coated
w ith fome kind of powder, which was occafionally varied.

The above ftatement will convey a general idea of the man-
ner of making the experiments ; but, that the whole may be
more fully comprehended, the following defcription of the in-
ftruments has been added by Mr. Cavendiih.*

DESCRIPTION OF THE INSTRUMENTS.

Defcription of ^n tne ^r^ feries of experiments, 28 pieces of coin were
machinery for fixed to a frame, and over each of them was placed another

eSofffic-6 Piece> which was Pre(red a§ainfl k by a weight; and thefe
tion on coin. upper pieces were all connected to a fecond frame, fo that, in

confequence of the motion communicated thereto by cranks,

each upper piece was rubbed backwards and forwards upon

that which was under it.

Fig. 1, (Plate XIV.) reprefents a plan of this intlrument ;

and Fig. 2 is a vertical lection of it, drawn parallel to the

line AB.

The upper frame, or that to which the upper pieces of coin

are connected, is of brafs, and confifts of four bars, Fig. 1,

AB, B6, ba, and aA, with three crofs bars Cc, Cc, Cc.

, * The inftruments were made by Mr. Cuthbertfon, of Poland-

ftreet, who alfo had the care of them during the experiments which
were made at his houfe.

The

•EXPERIMENTS ON VARIOUS ALLOYS OP GOLD. 299

The lower frame confifts of a board, placed immediately D* fcription of
under the upper frame, and is expreffed in Fig. 2, by the letters determining die
LL. effe&s of fric-

The upper frame is fupported by two vertical boards, ex- tl0I? on C0IIU J
lending the whole length of the tides B6 and Aa, fo that the
ends of them are (e'en in Fig. 2, and are denoted by the letters
DD, DD. Thefe boards are fattened to the upper frame, and
to the table upon which the apparatus ftands, by hinges, fo
that the upper frame can move freely in the direction BA, but
can nave no motion in the direction perpendicular thereto.
Thefe vertical boards are omitted in Fig. 1 ; for, as the inten-
tion of this defcription is not to give a detail of all the parts of
the inuruments, but only to explain their manner of acting, I
have taken the liberty to omit fuch parts as tended to produce
an intricacy in the figures, without being neceilary to this
object.

Tire difpofition of the pieces of coin on the frames, is re-
prefented in Fig. 1 . Nnn denote one of the connecting pieces,
by which the upper pieces of coin are connected to the upper
frame, and in which the fmall circle reprefents the pofition of
the coin ; the large circle is the part which fupports the weight,
and nn the part by which it is connected to the upper frame.

To avoid confufion, neither thefe connecting pieces nor the
pieces of coin are reprefented in Fig. 2 ; but, inftead thereof,
a fection of one of thefe pieces is given in Fig. 3, upon a larger
fcale. ,.

In this figure, LL is the lower frame, and C one of the bars
of the upper frame ; y is one of the lower pieces of coin, which
is bedded and fixed firmly in a brafs focket x, fattened to the
lower frame ; u is the piece of coin to be rubbed againft it,
which, in like manner, is fixed in another brafs focket ry;.->N»
is the connecting piece, by whjch this focket is connected t
the* bar C of the upper frame. This piece turns on pivots, in
two fiuds n, fixed to the bar C, fo that it can turn freely on
thofe pivots in a vertical direction, but cannot be perceptibly
fhaken horizontally.

Z is the weight by which this connecting piece is prefled
down ; it is round, and is placed with its centre exactly over
that of the focket w.

It muft be obferved that, in the construction of this machine,
three things principally demanded attention.

l/hThat

300 EXPERIMENTS ON VARIOUS AtLOYS OP GOLD.

Defcription of 1ft. That the piece? of coin fhould all move equally. >

machinery for 2dj That th ftlou|d aJ1 be prefl-ed agajnft. the lower

determining the . , . ,. / . . , ,

effe&soffric- pieces by the lame weight. And,

two on coin. 3dly. That they mould bear flat againft them.

As to the firft requifite, it is evident that the pieces muft all
move alike, excepting fo far as proceeded from the fpringing
of the parts of the machine, or from the make in its joints,
both of which were very fmall.

Secondly, as the connecting pieces move freely in a vertical
direction, it is clear that the force with which the upper piece
of coin is prefled againft the lower one, depends only on its
own weight, on that of the focket w, on that of the connecting
piece Nn, and on the weight Z by which it is loaded ; fo that
the fecond requifite is thus eafily obtained.

Thirdly, The connecting piece N/i bears againft the focket w
only by the pin p, which enters into a hole in the centre of the
focket, fo that the two pieces muft neceflarily bear flat againft
each other; but, as this pin alone would not have prevented
the focket from turning round on its centre, two other pins
n II were fixed into the connecting piece, and entered into
flits made in the focket near its circumference, allowing no
more fliake than was neceflary to prevent it from flicking; and
thus the motion round the centre was effectually prevented.

It may be obferved, that the pieces might have oeen made
to bear flat againft each other by fixing the fockets w in gim-
bals ; but, as the method above defcribed was effectual, and
much eafier made, it was preferred.

It may be alfo remarked, that the breadth of the bars Cc, as
reprelented in Fig. 1, is not fufficient to prevent them from
fpringing considerably ; for this reafon, a method of ftrength-
ening them was employed, which anfwered the purpofe per-
fectly well, but is omitted in the drawing, as it could not be
eafily reprefented.

It was at firft intended, that the lower frame fhould have re-
mained fixed, and that only the upper one fhould have moved;
but, in a previous trial, in which two pieces of metal were
rubbed backwards and forwards upon each other in the fame
line, with a view to difcover what weight would be neceflary
to make the pieces wear tolerably faft, it was found that for a
time they diminiflied flowly, but that little furrows or gullies
were foon worn in them, and that then the diminution was

rapid

EXrERlMENTS ON VARIOUS ALLOYS OF GOLD, SOI

rapid. It was alfo obferved, that the gullies in the upper Description of
pieces correfponded to thofe in the lower ones ; fo that it was ^^"in^l*
impoffible that the pieces of metal ftiould touch each other in effeds of fric-
thofe places where the diminution was raoft rapid, and confe- tlon on com»
quently (he gullies mud have been formed by the particles of
metal which had been abraded, and which fubfequently had
become accumulated.

It feemed to Mr. C. that the mod probable way to prevent
the little furrows or gullies from being thus formed, would be,
to conftruct the inftrument in fuch a manner, that the direction
in which the pieces rubbed upon each other fliould continually
vary. The following contrivance was therefore adopted, by
which the pieces were prevented from rubbing together twice
in the fame direction.

In this method, the lower frame, as well as the upper, is
fupported on two moveable vertical boards ; but, whereas the
boards fupporting the upper frame are placed parallel to Bb,
in confequence of which the frame can move only in the di-
rection BA, thefe are placed parallel to BA, fo that the frame
can move only in the direction Bb.

EE is the axis by which the upper frame is moved : this
turns in fixed fockets at SS, and is turned at each end into the
form of an eccentric circle, which acts as a crank ; fo that, by
means of the levers EK, which at one end turn on thefe ec-
centric circles, and at the other end turn on joints fixed to the
upper frame, this frame is made to move $ of an inch, in the
direction BA, during one half of the revolution of the axis,
and as much in the contrary direction, during the other half
revolution.

ee is an axis of the fame kind, ferving to move the lower
frame. HH is a windlafs, which turns thefe two axes by
means of the toothed wheels F,/, which work in the toothed
wheels G, gf fattened to the axes EE and ee. TTTTT is the
table upon which the apparatus Hands.

The wheel F has 90 teeth, /has 75, and G, g, have eacf>
20; fo that the axis EE makes fix revolutions while ee makes
five ; and, at a medium, thefe axes make about four revolu-
tions to one of the windlafs. A counter is placed fo as to (how
the number of revolutions of the windlafs.

If the two frames had performed their vibrations in the fame
time, no advantage would have been gained, for the pieces of

coin

302 EXPERIMENTS ON VARIOUS ALLOYS OF GOLD.'

Defcription of coin would ftill have moved upon each other always in the
machinery for fame jjne but as (he;r vlbrations are performed in different
determining the ' r

effeds of fric- times, Mr. C. (hews, that the effect muff be quite different,
tioa on coin. Tn;s contrivance, therefore, effectually prevented the pieces

from moving upon each other always in the fame line ; and it
feems alfo to have much diminished the difpofition which they
had to wear in gullies, but not intirely ; for, from the following
experiments it appears, that ftill fome few particles would be-
come occafionally collected, and then a<5ted as a grinding
powder, which accelerated the wear of the pieces. This was
obferved particularly to liappen to the pieces of gold alloyed
with an equal proportion of copper, and to the pieces of
copper, which were alfo more frequently worn in furrows or
gullies, than the other pieces of more ductile metal.

The motion of the pieces of coin upon each other, is greater
than it would have been if only one frame had been made to
move, nearly in the proportion of 3 to 2 ; fo that the whole
motion of the pieces, in each femi-revolution of the axes EE
or ee, is about -| of an inch, and therefore it is about three
inches in each revolution of the windlafs.

The inftrument employed in the fecond feries of experi-
ments, is fo fimple as not to require any drawing. It con-
fided only of a cubical box of oak, which meafured eight
inches each way, within tide. This box was moved by the
axis EE of the former inftrument, which was palled through
the middle of two oppofite fides, and was fixed in that pofi-
tion.

Fig. 4, reprefents a plan of the inftrument ufed in the third
feries of experiments, aaa is a horizontal table, turning upon
a vertical axis ; and BBBbbb is a fixed frame funounding it.

The pieces of coin are fattened to this fixed frame, by the
fame connecting pieces which were formerly employed, and
are prefled down alfo by fimilar weights. The diameter of
that part of the wheel againft which the centres of the pieces
of coin are prefled, is 29 inches; fo that, while this wheel
makes one revolution, the pieces are rubbed againft it through
the whole circumference of this circle, that is, through 91 -—
inches

- A fhallow groove ggg is cut in this wheel, in that part againft
which the pieces are prefled, in order to confine the powders
employed in the experiments; and the number of revolutions of
the wheel are marked by a counter.

By

experiments on Various alleys of gold. 3Q3

By the help of the inftruments above defcribed, it was pro- Defcriptionof
pofed to determine, as accurately as poffible, dSSST *?t*

lft. The comparative wear of foft and of hard gold. effeds of fric-

2dly. Whether coins with flat or with raifed furfaces furTertion^ coil%
the greateft lofs by friction, when fubjedted to it under fimilar
circumftances*.

It is fcarcely neceffary to obferve, that rigoroufly exact re- m

fults could not be expe&ed in all the minutiae of experiments
like the prefent; for, many circumftances, apparently but
trivial, produced almoft unfurmountable obftacles ; but, never-
thelefs, thefe did not impede the effential objects from being
inveftigated, and determined, in a manner fufficiently fatisfae-
tory.

Before the experiments are defcribed, it will be proper to
add, that, to obviate the irregular effects which would be pro-
duced by the inequality of the impreflions ufually employed for
coins, Mr. Cavendifli fuggefted a die, which was executed by
Mr. Pingo, and which confifted of round prominencies re-
gularly difpofed over the furface, fo that the effects which this
impreffion produced, during friction, were uniformly the fame
in every direction.

The firft experiments were intended to afcertain the different
wear of gold made ftandard by various metals; and the pieces
were rubbed againft each other by meaus of the firft-defcribed
apparatus, which the author calls No. J.

Some preparatory experiments were alfo made, to try the
effecls of this machine, as well as to determine, in fome mea-
fure, the comparative wear of gold made ftandard by copper,
of a mixture of gold and copper in equal proportions, and,
Iaftly, of copper.

* Although coins with protuberances on their furfaces, have been
generally fuppofed to fuffer more by friction than thofe which are
flat, yet, as this opinion has been questioned, and as feveral objec-
tions have been made to it by intelligent perfons, it was thought
expedient that the decifion of the queftion mould form part of the
prefent inveftigation.

(To be continued.)

30*

TRANSIT. OF MERCURY*

XIIL

Tranfit of Mer-
c»ry.

Mercury fecn
on the fun's
diflc, perfectly
round j

Obfervations of the Tranfit of Mercury over the Difk of the Sun;
to which is added, an Invcftigation of the Caufes which oftejt
prevent the proper ASlion of Mirrors, By William H e r -
schel, ZL.D.F.R.S.*

JL HE following obfervations were made with a view to at-
tend particularly to every phenomenon that might occur during
the paflage of the planet Mercury over the fun's body. My
folar apparatus, on account of the numerous obfervations I
have lately been in the habit of making, was in great order for
viewing the fun in the Jiigheft perfection ; and, very fortu-
nately, the weather proved to be as favourable as I could pof-
fibly have wifhed it.

The time at which the obfervations were made, not being
an object of my inveftigation, is only to be confidered as de-
noting the order of their fucceffion.

November 9, 1802. About 40' after feven o'clock in the
morning, I directed a telefcope, with a glafs mirror of (even
feet focal length, and 6,3 inches in diameter, to the fun ; and
perceived the planet Mercury. It was eafily to be diftin-
guiflied from the openings in the luminous clouds, generally
called fpots, of which there were more than forty in number.
Its perfect roundnefs Would have been fufficient to point it out,
had I not already known where to look for it.

10h 0'. When the fun was come to a fufficient artftude to
fhow objects on its furface with diftinctnefs, I directed my
attention to the contour of the merculial difk, and found it$
termination perfectly (harp.

. , • From the Philofophical Tranfactions for 1803.

(To be continued. J

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I

D E X.

A.

Abyssinia, 161

Accum, Mr. Fred, his examination of the
fo called fait of bitumen, 251

Acids, their effect on the teeth, 38

Acofta, Jofeph, 163

Adams, Mr. Geo. 217

Air, dry and moift, refpecYive fpecific gra-
vities of, 242

Albumen, 19

Alcohol, inefficient to purify oil, 11.—
action of on the juice of plants, 19

Alkali, its ufe in purifying oils, 12

Alumine, a 60

American Philofophical Society, 63, 64

Andrew, Mr. his method of clearing the
lunar diftances, 43

Andromeda mariana, 166

Antimony, 288

Anti-incendiary liquid, 103

Antilles, 177

Arcturus 76

Arfenic, 287

Atmofphere, how fupplied with oxigen,
184

Azalea nudiflora, 170

Azote, 25, 187

E.

Banks, Sir J. 32

___ report of the ftate of his

Majefty's flock of fine wooled Spanifh
(heep, 65

Barton, Dr. his account of the poifonous
honey of North America, 159
Vol.. V.

Baffe, his method of preparing muriatic

ether with fimple acid, 221
Beaume, 178
Bay alewife, z *
Beccaria, 217
Bees, maftic of, 48
Berthollet, M. 281
Bird lime, 24

Bitumen, fait of analyfed, 251
Black, Dr. 208
Blafhing fcrew, 32
Blood, ferum of ufed In a procefs of paint*

ing, 139
Bones, on the nutriment of, 221
Boggy land, draining of, 28
Books, new, 63
Borage 27
Borer for draining boggy land, description

of, 29
Boftock, Dr. 225, 227
Botany, 145
Boulton and Watt, their time-piece for

regiftering the attendance of watchmen,

158
Brogniart, 184
Brownriggi Dr, 23 J
Bruce, Mr. 161
Buckthornr 27

Cadet de Vaux, 22 1

Calculus pulmonary, 206

Candles, on the relative quant'itiei of li^hfi

afforded by them, 219
Capella, 76
Cardan, 204

b Carbonc^

INDEX.

Carbonel, M. his new method of painting,

*39

Catechu, experiments on, 270. ■ — Compo-
nent parts of, 275. — Of Bengal, 276.
—Of Bombay, ib.

Cavendifh, Mr. 229

»..,- ..— «. experiments of gafes ab-

forbed by water, 234, 288

Carbonic acid gas, abforption of by water,
232

Curaudau, Cft. his memoir on the nature
and new properties of the pruflic acid,
277

Chad fifh, 3

Chalk, its effecl: on the putrid fiibftance
of oil, 9;— ufed in purifying oils, 12

Chenevix, R. Efq. on the quantity of ful-
phur in folphuric acid, 126.— His ac-
count of a pretended new metal, 136

Chimboraco, 207

Chocolate, Parmentier on thecompofition
and ufe of, 175

Clouds, ftrata of, 246

Clupea Tyrannus, 1

Clupea non defcripta, 2

Coals, 226

Cobalt, 289

Cocoa, 177

Cod-oil, purification of, 13

Columella, 174

Combination, ancient lock of, 203

Cor/ica, 173"

Crawford, Dr. 35

Crampton, Dr. his Analyftt of a pulmo-
nary calculus, 205

/ D.

Dalton, Mr. his obfenvations on tha zero

of heat, &c. 34
Dalton, Mr. 233, 240
D<ircet, Cit. his defcription of a new pro-

cefs of refining, 70
Datura Stramonium, 170
Davy, Mr. his galvanic apparatus, 216

Davy, Humphry, Efq. his experiments cm

the conftituent parts of certain aftrin-

gent vegetables, 256
Day, Samuel, Efq. his defcription of a

watchman's regulator, 133
Delaville, 184
De Luc, 35
De Luc, Mr. 208
Demachy, 178
Deyeux, M. 261
Detonation, experiments on, by Citizen

Robert, 189
Diodorus Siculus, 179
Diftillation, Edelcrantz on, 156
Dize, Cit. 72
Dodd, Mr. R. his report of the intended

North London canal, 142
Doflie, Rob. on the purification of fifh

oil, 5
Dwarf laurel 165

Eulefton, Thos. his borer for draining
boggy land, 28

Edelcrantz, Sir A. N. his defcription of a
new ftatical lamp, 93.— His method of
remedying the inequality of heat in dif-
tillation, 156

Edelcrantz, Sir A. N. defcription of hi*
Swedifh telegraph, 193, 228

Elder, 27 '

Electricity, 59.— Application of to medi*
cine, 109

Enamel of the teeth, 36

Ether inefficient to purify oil, H

Ether, 260

Evelyn, 164

Exeter, Rt. Hon. the marquis of, his ac-
count of a time-piece for regiftering the
attendance of watchmen, 158

Exotics, 152

Expanfion of thermometer, tables of, 211,
212, 213

-Fecula,

INDEX.

ffcicu'lay colouring matter of, lj

differs from gluten, zz

' green and white, 21
Fires, extinction of, 103
Fiih oil, purification of, 5
Fifh hermaphrodite, 60
Fitz- James, Mr. 250
Florida, 165
Fontana, 51
Fortis, M. 101
Fofter, Mrs. 137
Fourcroy, on the gluten of vegetables, 24,

51, 205, 257
French Inftitute, 54

Galls, experiments on the infufion of,

261
Galvanic refearches, 58
Galvanifm, fuppofed difference between it

and the electric fluid, 60 J

Galvanic fliock, 6 1 , 109
• gutta-ferena cured by, in

■ hydrophobia cured by, 112
' ' ■ apparatus by Mr. Davy,

216
Gas, emifiion of from the fkin, 52, 53'
Gafes, apparatus for galvanizing, 217
— — abforbed by water.— Henry on quan-
tity'of, 230, 231

■ ■ on the extract-Ion of from fpring

water, 236
-■' general law of abforption of, by

water, 239
— ■ table of abforption of, 241
Gluten and fecula, differences of, 22
Gold, on the comparative wear of, 286

" on various alloys of, 287
Gough, Mr. John, his experiments on

ventriloquifm, 247
Graphometer, fubterraneous, 283
Gregor, The Rev. Wm. 225
Gun-lock, improvement of, 29^

M.

Htrrup, Mr. Robert, on the caufet by
which the oxigen of the atmofphere is
fupplied, 184

Hatchett, Mar. ,259

Hatchett, Charles, Efq. his experiments
onrthe alloys, the fpecific gravity, and
the comparative weight of gold, 286

Heavens, Herfchell on the conftruction of,

75

Heat, fpecific, of fleam at different tem-
peratures, 209

Hemlock, 169

Henderfon, Mr. 251

Henry, Mr. Wm. his experiments on the
_ quantity of gafes abforbed by water at
different temperatures, 229

Heracleapontica, 171

Hermaphrodite fifh, 60

Herfchell, Dr. on the construction of the
heavens, 75

his* obfervation of a tranfit of-

Mercury over the fun's difk, 78^

Highlands, honey of, 162

Honey, red, 161

intoxicating, ib.

Hooke, Mr. B. on the probability that
water may be formed at low heats, z%%

Houfe-leek, 26

Hydrogen, oily, 97

h

Indians, 167

Ingenhouz, Mr. 51, 185

Inftitute of France, 54

Inftitution, Royal, 221

Joffe, Cit. his memoir on the phyfical and

chemical examination of the teeth. 36
Iron, the difoxidationof, 99
Jurine, 51

Kalmia auguftifolia, 16 K
Kerr, Mr. 276

Kir wan,

INDEX.

Kirwan, Richard, on rain, 120

Kirwan, 146

Kirwan, Richard, Efq. on the ftate of

vapour fubfifting in the atmofphere, 207,

242
Kirkwall, Lord, 33
Knight, Mr. Richard, his apparatus for

breaking up logs of wood, 31
Komarzewiki, M. his graphometer, 283

Lambert, 244

Lambe on fpring water, 213

Lagrave, 60, 62

Lamp, new Statical description of, 93

■ an improved, 133

Lafteyrie, Cit. 48

Latham, Mr. 203

Latrobe, B. H. on the Clupea Tyrannus

and Onifcus Praeguftator, 1
Lauruftinus, 153

Lead, calx of, applied to fetid oils, 20
— ■' 224
Light, on the relative quantities afforded

by candles of different dimensions,

Lloyd, Mr. 32

Lime, its ufe in the purification of oil, 8

Lime, oxalate of, 40

Lime, phofphateof, 43

Linnaeus, 162

Linne, 2, 4

Lock, ancient, 263

Loufe, an infect in the mouth of a fiih, 2

Lunar obfervations, Mr. Andrew's method

of clearing, 43
Lunar volcanoes, 201

M.

Machinery, defcription of for determining

the effects of friction on coin, 298
3A agnefia alba, its operation on fetid oils,

9

Magnefia, fulphate of, 225

3

Magnet compound horfe Shoe, 216

Mercury, a tranfit of, 304

Mercurial thermometer, 35

Metallic precipitates found in chocolate*
179

Meterology, its connection with telegra-
phic obfervations, 201

Mexicans, 175

Milly, Count de, 51

Miller, 151

Moift air, 214

Moyfe, Dr, 251

Mud, fhovver of, 101

Mufchenbrook, 246

Mufkets for quick firing, 116

Myrtle, 149

N.

Nebulae, 90

News, fcientific, 54, 220

New books, 63

Nickel, 289

Night telegraph, 199

Nitrogen gas, 52

Nitrous oxide, abforption]of by water, 235

Nooth, Dr. 230

North America, poifonous honey of, 161

Oil, fifh, purification of, 5

Oil, train, 6

Oils, volatile, inefficacy of to purify

oils, 11
Oily hydrogen, Prouft on, 97
Onifcus praeguftator, 1
Onifcus phyfodes, 2
Opium, 26

Oranges, farinaceous coating of, 26
Organization, new, of the French initi-

tute, 55, 56, 57, 58
Oxalic acid, 42
Oxigen, confumption of, in the fyftem of

nature, 185

Oxigen

INDEX.

Oxlgen and hydrogen, mixture of, re-
markable fact refpe&ing their difappear-
ance in an inverted bottle with water,

Oxigenated muriatic acid, action of, on
green feculse, 17

Parmentier, 16

* — — Cit. on the compofition and

ufe of chocolate, 175

Parting, 71

Painting, a new method of, 139

Palladium, metal, the fo called, 136

Parkinfon, 64

Papin's digefter, 42

Parry, Dr. on Spanifh fheep, 68

Pattrick, Mr. his defcription of an im-
proved armillary fphere, 143

Paul, Mr. N. his improvement in the
iConftrucYion of lamps and reflectors,

133
Pearfon, Dr. 236
P. Metier, 131
Pheafants, 167
Phofphorus, the combuftion of by the in-

vifible rays of the folar fpettrum, 255
Plants, Templeton on the naturalization

of, 145
Plantations, 155 •
Precipitate, metallic found in chocolate,

179
Praeguftator, 1
Prieitley, M. 51

Dr. 185, 230
Prize queftion, 223
Prouft, profeflbr, on the fecula of green

plants, 16

■ 97, 220
Prouft, M. 256
Prony, 211

Propolis of bees, analyfis of* 48,

■ refin of, 49
Potafh, 24
Pouhon Water, 233

Prufllc acid, 277

■ — lixivium, 279

Pruffire, 277
Prufiiurets, ib.
Prufliatcs, ib*
Pyrites, ib.
Pyrmont water, 230

Quick firing, account of two muflcets for,
116

> ; ■' inventions for, by the Mar-

quis of Worcefter, 118

Rain, on, by R. Kir wan, Efq. XzX

— — Prognoftication of, 1 25

Raw filk, wax of, 26

Refining, new procefs of, 70

Refin of propolis, 49

Rhododendron maximum, 170

Ritter, Mr. his experiments on the invi-

fible rays of the folar fpectrum, 25
Robert, Cit. his experiments on detoaa-

tion, 189
Roffi, Cit. 11 j
Rouelle, 22
Roy, General, 214

S.

Saffron, 27

Sandtorius, 50

Saint Domingo, 175

Salix herbacea, 154

Sauffure, M. 242

Schmidt, Mr. his tables of expanfion,

211
Schmidt, his experiments on the ftate of

vapour fubfifting in the atmofphere, 242
Scientific news, 54, 220
Screw blafting, 33

Sea-lalt, its ufe in edulcorating oils, 10
Seguin, 35

*5«

S heldrake*

INDEX.

Sheldrake, 225

Sheep, Mendip, 66

■ Dorfet, ib.

Shuckburgh, fir George, 208, 248

Shock, galvanic, 61

Shower of mud at Udina, 101

Signals, 195

Sirius, 76

Soap lees, action of on fetid oil, S

Society of arts, 5

•— — galvanic, 60

— — — American philofophical, 63, 64

Solanum lycnperficum, 25

Solar fpectrum, on the invifible rays of,

*55

Somerville, Lord, on Spanifli fheep, 69

Sound, on the reflection of, 247

Spanilh iheep, 65

Specific gravities of vapour and air, 215

Stars, infulated, 76
" ■ double, 77

cluftering, 88

hi m groups of 89

Sugar cane, importation of into the Weft-
Indies and America, 175

Sulphuretted hydrogen gas, abforption of
by water, 235

Sulphate of Magnefia, production of from
the afhes of pit coal, 225

T.

Talc, electrical battery of, 216
Tannin, various in different vegetables,

257 ■

affinities of, ib.

Taffacrt, 132

Teeth, chemical examination of, 36

Telegraph, Swedifli, 193

— — — — Englifh, 201

Templeton, John on the naturalization of

plants,
Temperatures of boiling water at different

ftations of the barometer, table of, 209
Tennant, Mr. 226

Terra japonica, 270

Thenard, 132

Theodolite for mining, 283

Tranfit of Mercury, 304

Train oil, 6

— ■ — application of oxide of lead to,

10

Tranfpiration, 50

Trattner, 2

Trees, on the decortication of, 222

Trouflet, Cit. his memoir on the cutane-
ous aeriform tranfpiration, 50

Tyrannus, onifcus, 1

V.

Vauquelin, Cit. his analyfis of the maftic
of bees, 48

Van Aken, 103

Vauquelin, 131, 184,257

Van Marum, M. Experiments on extin-
gui filing violent fires with fmali quan-
tities of water, 103

Vapour in the atmofphere, on the ftate ef,
207

Volatile oils, inefficiency of to purify oils,
J 1

Volcanoes, lunar., 201

Volta, in

Virgil, 174

Vitality, agency of, 62

Von Zach, 106

W.

Walker, Mr. E. remarks on his experi-
ments on light, 219

Walker, Mr. Ezekiel, 251

Warwick, the Rt. Hon. the earl of, 116

Watchmen, mechanical method of afcer-
taining their diligence, 134

Water, its action on fetid oils, 11

Watt, Mr. 209

Wax, 26

Weftrumb, Mv 228

Wilfon,

INDEX.

Wilfon, Dr. Ijl

Worcefter, Marquir of, his inventions for
quick firing, 118

Xenophon, 172

Yeaft, artificial, method of making in

Germany and Sweden, 228
Young, Dr. 221

Zinc, 288.

2.

JSNO OF THE FIFTH YOCUMF.

Printed by \V. Stratford, Crown-Court, Temple-Bar.

f