Sporerse beagtedreest sens tekereleisssbeds 3)
eb pps bene wymsuns evens wae PORTE SES DSRS Des 3 |
pebscactierp soy isa seratiesea tesels
niet ii
i
rittesnts Seas! itstetiets Pitt seretaes
breesats ; canter ies
phot Serepene +t . set
iy oti { t bs eteree ei tes oh S8e8tieber :
jist ; 3 +f srirerictrnitty paisa tate " Kh fe :
Bisset ish Hank inna “iit b : i t
i peshantitpsetteet este tee < t
Viet wit : at “4 oti
iat Git ates ait
Ht : ' Tress
Arar sy
oe. +
So fTesete:
Be
ry
1]
#
: i
7
AY
ite 3
ieee
s
v
bots Re
Th
Hi
4 ' Witt | | | :
| : ta It
i nh |
ri |
oy hi. ;
3
it
if
it
(ty
a
JOURNAL
NATURAL PHILOSOPHY,
CHEMISTRY,
AND
oT i Me BES Be
VOL. VI.
Gllustrated with Enaravings:
———
‘BY WILLIAM NICHOLSON.
SSS “
LONDON:
PRINTED BY W's STRATFORD, CROWN-COURT TEMPLE-BAR FOR
THE AUTHOR, No. 10, SOHO-SQUARE; |
AND SOLD BY
G. anp J. ROBINSONS, PATERNOSTER-ROW.
=: Se >
1803.
Ae es |
amuile’? ineeotg ait ial aga, igh? Towonis.:
; tisha 4 ai tie: aniwil: Ms? nits big ober Me
Apodiad a wud bay 2 A. iT: ed oe ‘5 new ystasr:
E Hodis tees cides’ ry Pt Ww
E + ot Bt se r ee aM
asta Moot Bal eet nswoH arbi x a
GM soul ap de adinibey engi iG oS
yyewto) aw ayiatod ie Aine 3 t rons Tama! td oor,
) dosnt - aabusti pet Pe) i oe eis wing Me
Holliavel cial ony - seth oe Httlosaist ale crust «
| Ai patie? Problmgatae mee
rov * Laeger coders Hf eee ay re
haa Sieticobsl? “tak 2A a
y «oH ane boars wo NG
Seale: tac ie pat perranrsd » eg
tow ayer mV": ide Raton Ob tele iat
“eB RA hell bedsigad Hee
: “vie W enn} oy Re hy oe 4 pac. moan
ae “in aD ‘eat Sa a sille¥
i SOBRE ¢ wack ALS 2 4 b peaai ate so Bee 2 Be
aut. ite die’ weccriagede Seg ie mee of ‘cue ati 1st
bes Mh Ae eet Ra
ners
49)
es eee sd woke ieee i SOD) | ees
OE? Coated “ches vs nae
y ak 2 & Lt ; et Oe 5 Ag
* hate Mais pea
7 y * * + ~
e socsacs fod a ee ute
: ane att oF snirged.e On gs
i ta ass IMs pit “ie Saat ban: atts me Oe
ar (Cy ae at es “y . x XY
Ssinsialebl ; Ab ue @ tei boitoets er Sts: oie 8
9s zwenban). % ae a eteis YF oni a tb bi ae oF
onl wt Ras, a, bis a, a fine: Jorn giaaer oth ee
Be
ADVERTISEMENT.
‘Tur Authors of Original Papers in the present Volume,
are Mr. Frederick Accum; Mr. Irwine ; Sir. A. N. Edel
crantz; Dr. T. C. Hope, F. R. S. Edinburgh ; Anthony
Carlisle, Esq.; M. B. Donkin; Mr. Ezekiel Walker;
Thomas Thompson, M.©.; Dr. Boftock; Mr. Dalton ;
Edward Howard, Esq. F. R. S.; Mr. A. Woolf; Andrew
Duncan, M.D. F. R. S. Edinburgh; Dr. Prince ; Mr.
J. C. Hornbiower, and Mr. G. Smart. Of Foreign Works,
M. Regnier; Wiegleb; Guyton; Curaudau ; Baunach ;
Payffé; Parmentier; Steinacher; Schaub; Nicolai; Bouillon
la Grange; Klaproth; Lomet; Tromfdorff; Seguin; Ritter
Thenard ; Vauquelin; La Place; Guyton-Morveau ; Von
Hombolt; Raymond; Berthollet, and Haffenfratz. And
of English Memoirs abridged or extracted, Wm. Her-
schell, L. L. D. F. R. S.; Richard Chenevix; Esq. F. R.S.
and M. R.T. A.; aikeehty Davy, Esq.; Wm. Hyde Wel-
laston, M.D. F.R.S.; Sir H. C. Englefield, Bart. F. R.S.;
James Smithson, Esq. F.R.S. P.R.1.; Mr. James Woart ;
William Fairman, Esq.; Charles Hatchett, Esq. F. R. 8.5
The Right Hon. C. Greville, F. R.S.; Mr. John Dalton;
Everard Home, Esq. F. R. S.; and Andrew Duncan, ues
M.D. F. R. 8. Edinburgh.
Of the Engravings the Subjects’ are, 1. Dr. a:
Apparatus for illustrating the Doctrine of Preponderance.
2. Apparatus for Experiments with Spouting-Fluids. 3. A
Lock of Combination by M. Regnier. 4. Solar Phenomenon
obferved, by Sir H. Englefield, Bart. 5. Figure to fhew the
Proportion of the magnified Images of the fame Star at
different Times, by Dr. Herschel]. 6. Sir A. N. Edelcrantz’s
Method of Raifing Water in Worm*Tubs, Condensers, &c.
7. Eudiometric Apparatus, by Dr. Hope. 9. Veffel for In-
closing
ADVERTISEMENT.
closing Anatomical Preparations, and other Objects. 9. Cry-
stal of Electrical Calamine. 10. Curaudau’s Furnace fo,
evaporating by a regulated Economical Heat. 11. Mr.
Woart’s Method of fupporting decayed Timbers in Build-
ings. 12. Mr. Fairman’s Method of extreme Branch-Graft-
ing. 138.Cit. Lomet’s Addition to the Sextant for meafuring
Vertical and Oblique Angles at the fame Inftant, from an
_ Air Baloon, for Military Service. 14. An Apparatus. for
drying Precipitates, and for Processes of Congelation, by
Mr. Accum. 15. Hydraulic Combination for rendering the
Atmospheric Pressure effective in Raising Water in Worm,
Tubs, by Edward Howard, Esq. F. R.S. 16. Improve-
ment in the Syphon, by the same. 17. A Rotatory Apparatus,
by which the Power of a Steam-Engine is equalized without
a Fly, and the Work may be stopped, or fet off in any Part
of the Stroke, by Mr. A. Woolf. 18. Improvement in —
Mr. Ezekiel Walker’s Reflecting Quadrant, by the Inventor,
19, A new Steam Valve, which indicates the Strength, and,
without Attendance, regulates the Emission of Steam from
a Boiler, by Mr. A. Woolf. 20. Mr. George Smart’s Ma-
chine for Sweeping Chimnies without Climbing Boys. 21. An
improved Chemical] Furnace. 22. Two Views of the Great
Fiery Meteor which appeared Noy. 13. 1803.
Soho Square, December, 1804.
ea ee 8 CoCon re NL
TO THIS SIXTH VOLUME.
SEPTEMBER, 1803.
Engravings of the following Objeéts; 1. Dr. Young’s Apparatus for illuftrating
the Doétrine of Preponderance; 2- Apparatus for Experiments with Spouting
Fluids; 3. A Lock of Combination, by M. Regnier; 4. Solar Phenomenon
obferved by Sir Henry Englefield, Bart. 5. Figure to fhew the Proportions of
~ the magnified Images of the fame Star at different Times. By Dr. Hertchell;
6. Sir A. N. Edelerantz’s Method of eafily raifing Water in Worm ‘Tubs,
- Condenfers, &c. 7, Eudiometric Apparatus, by Dr, Hope.
I. Experiments and Obfervations on the Compound of Sulphur and Phof-
phorus, and the dangerous Explofions it makes when expoled to Heat. By
Frederick Accum, Praétical Chemift and® Teacher of Chemiftry. Com-
municated by the Author. - ». ~ - - 4 - - 1
IJ. Obfervations of the Tranfit of Mercury over the Ditk of the Sun; ‘to
which is added, an Inveftigation of the Caufes which often. prevent the
proper AStion of Mirrors. By William Herfchell, LL.D. F.R.S. 8
I1I. Obfervations on the Chemical Nature of the Humours of the Eye. By
“Richard Chenevix, Efq. F. R. S. and M. R. 1. A. - - - 2}
1V.°A Letter from Mr. Irvine concerning the late Dr. Irvine, of Glafgot,
his Doétrine, which afcribes the Difappearance of Heat, without Increate of
Temperature, to a Change of Capacity in Bodies, and that of Dr. Black,
_which fuppofes Caloric to become latent by chemical’ Combination with
Bodies; with particular Remarks on the Miitakes of Dr. Thompfon, in his
Accounts of thefe Doétrines. + - - - - - - 25
v..An Account of fome Experiments and Obfervations on the conftituent
~ Parts of ‘certain Aftringent Vegetables; and on their Operation in ‘Tan-
“ning. By Humphry Davy, Efq. Profeflor of Chemiftry in the Royal Infti-
tution. - - - = - “ - - - - - 31
Vi. An eafy Method of raifing Water for the Purpofes of Refrigeration in
| Diftilleries, Steam Condenfers, &c. By Sir A. N. Edelerantz; communi-
cated by the Inventor. ey = - - - - - - 41
VII. Defcription of a new Padlock of Security with Combination. By Citi-
zen Regnier. - = - - - - - - yet: 43
VIII. Obfervations on the Quantity of horizontal Refraétion ; witha Method of
meafuring the Dip at Sea. By William Hyde Wollafton, M.D.F.R.S. 46
1X. An Account of Two Halos, with Parhelia. By Sir H. C. Englefield,
Bart. F. R. S. - - : z - _- - 54
X. A Defcription of Dr. Young’s Apparatus for illuftrating the Doétrine of
Preponderance, with an Account of an Experiment on the Velocity of Water
flowing through a Vertical Pipe. eh PY = - - - - 56
XI. Account of a fimple Eudiometric Apparatus conftruéted end ufed by
Dr. T. C. Hope, F. R. S. Edinburgh. : Shige sc aie a1 Mink Gl
Scientific News, 62.—Combuftion of Metals in non-refpirable Gales, by means
of Galyanifm - - - - - - - - - - - ib.
OCTOBER, _
ii EON TENTS:
OCTOBER, 1803.
Engravings of the following Obje&s: 1. Veffel for inclofing Anatomical Prepa-
rations and other Objects; 2. Cryftal of Eleétrical Calamine. ' By James
Smithfon, Efq. S. Curaudau’s Furnace for Evaporating by a regulated econo-
mical Heat; 4. Mr. Woart’s cheap Method of fupporting decayed Timbers in
Buildings ; 5. Method of extreme Branch Grafting, By Wm. Fairman, E({q.
I. Analyfis of the Egyptian Heliotropium, a Mineral lately imported from that
Country. By Frederick Accum, Praétical-Chemift, and Teacher of Che-
miftry. Communicated by the Author. - m4 - - 65
II. Method of clofing wide mouthed Veffels intended to be kept from cem-
municating with the Air. In a Letter from Anthony Carlifle, Efq. 68
IlI. Extraét of a Letter from Toulon to General le Vavafleur, Infpeétor of the
Materials of the Guns of the French Navy, on the Changes which Caft Iron
undergoes by remaining long in the Sea. - : 710
IV. On the Antiquity of the Invention of Gun-powder, and its firft Applica-
tion to Military Purpofes.. By Mr. Wiegleb. - - - 71
V. A Chemical Analyfis of fome Calamines. By James Smithfon, Efq,
F.R.S.P.R.I. From the Philofophical Tranfactions for 1803. - ~~ 74
VI. Table of the Radii of Wheels, from Ten to Three Hundred Teeth. The
Pitch being two Inches. By Mr. B. Donkin, Millwright, Dartford, Kent. 86 *
VII. Account of the Pyrometer of Platina. By Citizen Guyton. - 89
VIL. Letter from Mr. Ezekiel Walker on the Proportion of Light afforded by
Candles of different Dimenfions. - - = us £ 90
IX. On the Compounds of Sulphur and Oxygen. By Thomas Thomfon, ,
M.D. Leéturer on Chemiftry in Edinburgh. From the Author. 92
IX. Further Experiments and Cbfervations on the Effervefcences of Walls. In
a Letter from Dr. Boftock. - - - - ~~» 109
X. Philofophical Obfervations on the Caufes of the Imperfetion of evapo-
rating Furnaces, and on a New Method of conftruéting them, for the eco--
nomical Combutftion of every Defcription of Fuel.. By C. Curaudau, corref-
ponding Member of the Pharmaceutic Society of Paris. . 114
XI. Correction of a Mittake in Dr. Kirwan’s Effay on the State of Vapour
in the Atmofphere. By Mr. Dalton. - z c g t18
XII. Cheap and. effeétual Method of fecuring Beams of Timber in Houfes or
elfewhere, which have been injured by the Dry Rot, or are decayed by Time.
By Mr. James Woart. - - f s 120
XIII. Account of the Method of extreme Branch Grafting. By the Inventor
William Fairman, Efq. - b ss rs e ah 194
XIV. Obfervations on -feveral Pharmaceutical Preparations, by Cit. Stein-
acher, Druggift at Paris. Abridged by Citizen Parmentier. ~ 130
Scientific News, 184.—Extract of a Letter from Dr. Schaub to Mr. Parkinfon,
ib.—-Meteoric Stones, 155.—Abftract of a Memoir on the Febrifuge Principle
of Cinchona, 136.—Query by a Correfpondent refpeéting the Auguftine
Earth, 139.—Spaniard faid to refift high Degrees of Heat and {trong chemi-
cal Agents, 1b.—Method of giving Malt Spirits the Flavour of Brandy, 140,
—Preparation of a Lute proper for Chemical Operations.. By C. Payfle, ib.—«
Two new Quadrupeds, 141.—Prefervation of Iron from Ruf = - ~— 142
Account of Books, 143.—Philofophical Tranfagtions of the Royal Society ‘of
London, forthe Year 1803, Part I. 143.—An Effay on the Law of Patents
for new. Inventions ; to which are prefixed Two Chapters on the general
Hiftory of Monopolies; with an Appendix, & i 144
NOVEMBER,
,
*
CONT £ BTS. itt
NOVEMBER, 1808.
Engravings of the following Objeéts; 1. Mr. Woart’s Method of fecuring Tum-
~ bers which have been injured bythe Dry Rot; 2. Cit. Lomet’s Addition to the
Sextant for meafuring vertical and oblique Angles at.the fame Inftant from ¢n
Air Balloon, for Military Service; 3. Apparatus for drying Precipitate, and
for Proceffes.of Congelation. By Mr. Accum; 4. Hydraulic Combination
for rendering the Atmofpheric Preflure effective in raifing Water in Worta
Tubs. By Edward Howard, Efqg. F. R.S. 5. Improvement in the Syphon.
By the fame; 6. Rotatory Apparatus, by which the Power of a Steam Engine:
is equalized without a Fly, and the Work may be flopped or fet off in any’
Part of the Stroke. By Mr. A. Woolf; 7. Improvement in Mr. Ezekiel}
Walker’s Reflecting Quadrant. By the Inventor,
I. Experiments aud Obfervations on the various Alloys, on the Specific Gras
vity, and on the comparative Wear of Gold. Abftracted fram the Memoir of
_ Charles Hatchett, Efq. F. R. S.in the Philofophical Tranfactions for 1803. 144
II. A Memoir on the Appearance of Speétres or Phantoms occafioned by Dif.
eafe, with Pfychological Remarks. Read by Nicolai to the Royal Society of
Berlin, on the 28th of February, 1799 = z = 16]
II. Analyfis of Ambergris; by Cit. Bouillon LaGrange - - 179
IV. An Account of fome Stones faid to have fallen on the Earth in France; and
of a Lump of native Iron, faid to have fallen in India. By the Right Hon,
Charles Greville, F.R.S. - - > - - - 187%
¥. Analyfis of the Natrolite. By Klaproth - - - 19%
VI. On the Employment of Aeroftatic Machines in the Military Science, and
for the Conftruction of Geographical Plans. By Cit. A. F. Lomet 134
VIE. Chemical Analyfis and Properties of Arfeniated Hidrogen Gas, By Pro-
feffor Trom{dorff - - - - - - 208 ~
VIII. Account of an Eudiometric Apparatus, contrived and ufed hy Dr.
Hope, Profeflor of Chemiftry in the Univerfity of Edinburgh ~~ 210)
1X. Defcription of an Apparatus for drying the Produéts of Chemical Analyfis,
which is alfo ufeful for Experiments of Congelation. By Mr. Fiederick
Accum. Communicated by the Inventor - - - 212
X. Letter from Mr. Accum, in anfwer to the Enquiries of a Correfpondert
refpecting the Procefs for obtaining the Agufine Earth - 214
XI, Letter from a Correfpondent concerning the Method propofed by Mr.
Carlifle for clofing wide-mouthed Veffels - - - 21h
XIE. Account of an Experiment fer fupplying Worm Tubs and other Refrigera+
tories by the affiftant Preilure of the Atmofphere, which proved unfuccefs-
ful, on a large Scale ; to which is added an Improvement for extending the
ufeful Application of the Syphon, By Edward Howard, Efq.F.R.S. Ina
Letter te the Editor - - - -. - - 216)
XIII. A Method of equalizing the Motion of a Steam Engine without the
Affiftance of a Fly Wheel. By Mr. Arthur Woolf, Engineer, Communi-
cated by the Inventor - - - - - - 218
XIV. Improvement by which the’additional Arc in Mr. Ezekiel Walker’s re-' |
flecting Quadrant is rendered unnecéflary. In a letter fromthe Inventor 219
Scientific News, 221,~-Abftra&t of Cit. Seguin’s Inquiries concerning Fermen-
tation, ib.—Additional Experiments of Mr. Ritter, of Jena, on Galvanic Phe-
nomena, ib.—Abftraé&t of fome Remarks on the Acetite of Lead, by Cit.
Thenard, 223.—The Arachis Hypogea, or Ground Nut of the Welt Indies,
cultivated in France for its Oil = - ae - 224
DECEMBER,
iv _ SONTENT 5.
DECEMBER, 18053.
Engravings of the following Objects: 1. A. new Steam Valve which indicates the
Strength, and without Attendance, reculates the Emiffion of Steam from 4
Roiler. Communierted by Mr. A. Woolf the Inventor; 2. Mr. G. Smart’s
Machine now in daily Ufe for Sweeping Chimnies, without Climbing Boys;
3. Improved Chemical Furnace; 4. Two Views of the great Fiery Meteor,
which appeared Nov. 15, laft.
3, Letter from Andrew Duncan, M. D. F.R.S. E. containing Experiments
and Ob{ervations on Cinchona, tending ae scm to shew that it does not
contain Gelatine - - - - 225
II. Letter from a Correfpondent, containing Dilspuiitoasiy on the Phantafins
of Nicolai, and other Derangements of the : Animal Syftem. - 229
JIT. Experiments on the Subltance valeeey called Gum Kino. By Cit.
Vauquelin =e
WV. Extract of a Taree from Dr. Piigee cemuettine ie Aig-Pump. 235
VY. Memoir on the Tides. By Cit. Lapiace : 239
VI. Abftrac&t of a Paper by Cit. Guyton-Morveau, paeiled an Examination of a
native Carbonate of Magnefia. - - 4 a 240
VII. Curious Particulars reipecting the Mountains and Volts and the Ef-
fe& of the Jate Earthquakes in South America, with Remarks on the Lan-
guage and ree of the fprie and other ak eae BY, M. A. Von Hom-
boldt. - 242
VIH. Method of meafuring any Aliquot Part of an Tact by a Sarit which
gives no fuch Part in its Turn ; and Obfervation on an Error of Edwards in
placing the Eye- Step of refleéting Meleiooues. In a Letter from Mr, J. C.
Hornblower. - 247
7X. Account of a new ‘Aptian cuaiiructed die the Pie oF meafuring the
Elaftic Force, and regulating the Emiffion of Steam from the Boiler in which
it is generated. Communicated by the is innit Mr. Arthur Woolf, En-
gineer. = - 949
X. Journey. to re pitas of Mont- Bardy By Cit. Bamtad, 250.
XI. Notice of a Method of giving the Apres of Cotton to Hemp or
Flax. By Cit. Bertholiet. 252
XII. Defcription of a Machine now in cata cant daily “Ute, for cleanfing
Chimnies, without the Affiltance of Climbing-boys, and with much greater
Effect than is produced by that Method. Communicated by the Inventor, Mr.
Chriftopher Smart, of Ordnance Wharf, Weftminger Bridgee W.N. 255
XU. Experimental Eilays on the Contiution of mixed Gafes; on the Force
of Steam or Vapour from Water and other Liquids in different Temper-
atures, both ina Torricellian Vacuum and in Air; on Eveporais and on
the Expanfiou ot Gales by Heat. By John Dalton. = 2571
XIV. Delcription of the portable Furnace conitrusted by Dr. Black, and fince
improved. Ina Letter from Mr. Accum. 3 A 273
KV. Obfervations on the Stru&ture of the Tongue; {lluftrated by Cafes in which
a Portion of that Organ has been removed ey Ligature. BY Everard
Heme, Fig. F.R.S. — - - 216
XVI. Some Acci unt oF the large ne Mtbor ilies appeared on the 13th of
lat Month (November) 279
XVI. A Firft Memoir om Coloured Ghedows By Cit. Je Halfeatiaee: 282.
Scientific News, 286.—Ohbfervations on St. John’s Wort. By Cit. Baunach, ib.
Account of New Books, 288.-~The Edinburgh New Difpen{atory: containing,
1. The Elements of Pharmaceatacal Chemiftry ; ; 2. The Materia Medica; or,
the Natural, Pharmaceutical, and Medical Hittory of the different Subftances
employed in Medicine; 5. The Pharmaceutical Preparations and Compofitions,
&c. By Andrew Duncan, Jua. M. D, Fellow of the Royal College of Phy-
ficians, and Royal Society of Edinburgh, and Affociate of the Linnzan So-
ciety of London : = & ‘- - = Ib,
.
a
A
JOURNAL
OF
NATURAL PHILOSOPHY, CHEMISTRY,
AND
THE AR PS,
SEPTEMBER, 1803.
ART LE Lyf,
Experiments and Objervations on the Compound of Sulphur and
Phofphorus, and the dangerous Explofions it makes when exr-
pofed to Heat. By FrepertcK Accum, Practical Chemift
and Teacher of Chemifiry. Communicated by the Author.
Marcrarr, I believe, was the firft who noticed the Compound 6f
combination of phofphorus and fulphur; and Pelletier See ane
; , g fulphur; when
amined afterwards this compound, and pointed out fome of fir examined.
its properties *, The latter philofopher thowed, at leaft,
that the compound refulting from the union of phofphorus
and fulphur, in different proportions, is infinitely more fufible
than either of them taken feparately. Repeating the experi-
ments of the French philofopher, I had no apprehenfion that not fuppofed to
the combination of thefe two fimple bodies was attended, go auenaee with
under certain circumftances, with confequences which might
prove fatal to the chemical operator. And it is with the view
of preventing my brother chemifts from falling a facrifice to
unexpected dangers, that I fhall relate an accident, which
might have been attended with-the moft dangerous con-
fequences, before I ftate the properties which charaéterife
the compound which is the fubjeét of thefe lines. The ac-
* Journal de Phyfique, xxxv. 383,
Vor. VI.—SertemBEeR. B cident
‘
2) COMPOUND OF SULPHUR AND PHOSPHORUS.
Very dangerous cident alluded to, happened ‘in the following manner. Half
ri panents sae an ounce of phofphorus, cut into pieces of the fize of a pea,
of half an ounce was introduced into a Florence flafk, containing about ten
eee ounces of water ; one ounce of fulphur broken into fragments
water andone Of about the fame fize was added, and the whole placed on a
ounce of fulphur heated fand-bath, In a few minutes the union of the phof-
on a fand heat. ; ;
phorus and fulphur was effeéted. On leaving the whole in
the heated fand, for about,ten minutes longer, the empty part
of the flafk became filled with denfe white fumes, which in-
creafed more and more ; being unable to obferve what change
was taking place, I carefully removed the flafk out of the
fand-bath, and agitated the fluid in fuch a manner, that the
fufed compound of phofpnorus and fulphur ftillremained under
the furface of the water. But the inftant this was done, the
whole exploded in my hand with a tremenduous report; the
mixture of the burning phofphorus was. thrown into my face,
and occafioned very painful wounds; the pieces of the Florence
flafk were {cattered all over the laboratory, as fine as fand,
and the larger parts of the neck of this veffel were driven into
my right hand, as well as into the wall, to a confiderable
depth.
Repetition of Anxious to underftand the nature of this unexpeéted ex-
ee te aaa plofion I again expofed to heat, in a fimilar manner, two
alfo with larger drachms of phofphorus and half an ounce of coarfely powder-
asa gee ed fulphur, in a fmall flafk containing four ounces of water.
plofion asbefore. Lhe mixture, after having been left in a heated fand-bath
for about ten minutes, exploded with prodigious violence,
and a flafh of fire rofe up to the ceiling. The fame experi-
ment was repeated with larger quantities of phofphorus and
fulphur, three fucceflive times, with fimilar effeéts. Thefe
experiments were made at the laboratory, and in the prefence
of the Right Honourable Lord Camelford, who liberally
fupplied the materials for thefe and the following experiments, _
and permitted them to be made on his premifes,
Another ac- Before I advance any thing further concerning the accenfion
Be. of this compound, I beg leave to relate one inftance more of
nature. a fimilar nature, which happened lately inmy own laboratory,
Mr. Garden, a philofophical gentleman immerfed into a
veffel filled with warm water, a vial containing fix ounces of
phofphorus, to which had been previoufly added one drachm
of a mixture of phofphorus and fulphur. The contents of
the
G@OMPOUND OF SULPHUK AND PHOSPHORUS. g
the vial being liquified, (which was the intent of immerfing
it into heated water) he removed the vial out of the fluid,
taking care to clofe its orifice with his finger, and then agitated
it gently. The moment this was began the vial burft to
pieces with a report like a gun, the burning mixture was
thrown in all dire@tions, and the whole laboratory was filled
for fome hours with a very denfe cloud of white vapours.
Being thus fufficiently convinced of the danger which attends Careful ape i
the combination of phofphorus with fulphur, under fuch cir- eer
cumftances, I introduced into a Wedgwood’s tube clofed at Phofphorus,
+1. sulphur and
one end, two drachms of phofphorus, and double that quantity “YP akon
of fulphur. I then added four ounces of water, and clofed difttlation.
the other extremity of the tube with a cork, into which a
bended tube was cemented, which terminated under a glafs
cylinder filled with mercury, ftanding inverted in a bafon
containing the fame fluid. I then reclined the tube, and
applyed heat to that part which contained the phofphorus and
fulphur; on increafing the heat gradually'a quantity of gas forded a gas
i without exolae
was collected, which amounted to nearly two quarts. But <... :
no explofion took place.
To learn the nature of this gas, I transferred a quantity of which, added te
it into the water apparatus, and agitated it in contaét with jj 700 2)
that fluid ftrongly for a few minutes. Its volume was now fluid ;
confiderably diminifhed. On repeating the experiment in
diftilled water, it was found that this fluid abforbed nearly 4
of its own bulk. On fending up one part of atmofpheric air but took fire
into a cylinder holding fix parts of this gas, an inftantaneous we oa
inflammation enfued, the cylinder became filled with white mon air was
fumes, and a white cruft lined the inner furface of the glafs. added to.a larger
ues of the gas.
Finding thus that the gafeous product was decompofable by
atmofpheric air, I colleted another quantity of gas, in a fimilar The refidue of
manner as before; and mingled it gradually with oxigen ‘his 82s decom-
: > pofed by oxigen
gas till no further accenfion enfued. The gas left behind was azote.
amounted to 25 of the whole. It had all the properties of
nitrogen gas.
The white flakes which were colle&ted from the fides of the The precipitates
glafs cylinder, as well as from the furface of the mercury over ('"; alphas
- 4 E i ulphuric, and
which the experiments were made, attracted moifture rapidly, phofphoric acide.
and became converted intoa cream-like fluid. They confifted
of fulphur, fulphuric and phofphoric acids.
B2 Oxigenated
4. COMPOUND OF SULPHUR AND PHOSPHORUS.
Oxigenized muriatic acid gas acted more violently than
oxigen gas, when mingled with this gafeous compound over
mercury; the refult was a confiderable detonation, accom-
panied with vivid green light and denfe white vapcurs. ,
The gas was From the refults of thefe experiments it becomes obvious,
therefore a com- that the gas under examination was a compound of hydrogen,
Pound Re fulpl d phofphorus. And if we reafon’ from the nature
gen, fulphur, {ulphur, and phofphorus. nd if we reafon from the nature
and phofphorus;of the produétion of this gas, it is evident, that, during the
aétion of the phofphorus\and fulphur upon water, the latter
formed by the fluid is decompofed, though neither fulphur nor phofphorus
decompofition of - 5 + -— . wus tid ete Par :
ari es fingly taken, can effeét this decompofition ; this therefore is
that fluid is not fufficient to account for the unexpected explofion before
affected by either Aa tod
fingly. ;
Phofphuret of In order to fee whether phofphuret of fulphur were capable
fulpbur can de- of decompofing water in common temperatures, two ounces
compofe water ie . : : 3
at the common 0f it were covered in a vial with eight ounces of water, and
temperature. put afide for further examination. The vial having been left
unobferved, locked up in a clofet, for fome weeks; the corks
was found to have been thrown out of the vial, and the whole
infide of the clofet, which had been painted with white lead,
was completely blackened ; the parts neareft to the orifice of the
vial had a metallic afpeét, The fluid which was decanted
from the phofphuret of fulphur had a milky appearance, its
odour was like that of water firongly impregnated with ful-
phurated hidrogen ; its tafte was uncommonly naufeous, It
had a ftrong aétion on the greater number of metallic oxides.
On mingling it with concentrated nitrous acid, a confidera-
ble precipitate enfued, which after being dried on expofure to
air, was luminous in the dark and became converted into
fulphur. Another quantity of the water which was fuffered
to evaporate, fpontaneoufly depofited cryftals of a lemon
yellow colour, but of an indeterminate figure. ‘Phere re-
mained, therefore, no doubt but that phofphuret of fulphur is
capable of decompofing water at ufual temperatures,
As phofphuret — Phofpburet of fulphur, compofed of three parts of phofphorus
of fulphur de~
compofes airwith and one of fulphur, has.alfo the property of decompofing at-
greater rapidity mofpheric air with great rapidity. It may, therefore, be
pone aN employed more advantageoufly for eudiometrical proceffes
be a good eudio- than either phofphorus, or the fulphurets of earths, alkalies,
metrical agente or metals. If into a dry glafs tube clofed at the top, and
graduated
-
COMPOUND OF SULPHUR AND PHOSPHORUS, 5
graduated. into equi-diftant parts, a quantity of phofphuret of
fulphur, freed from adhering water, be poured, and agitated
in the tube, fo as to line a confiderable part of it within, a
vaft quantity of white vapour is produced the moment the tube
is immerfed in water; fo as to exclude the air. The vapours
will be abforbed by the water, and when no further clouds
appear, the procefs is at an end. ’ The refiduary gas will
then be found to be the quantity of nitrogen gas, which was
contained in the air experimented upon in the tube, This
procels is far more expeditious than the flow combuftion of
phofphorus. I muft, neverthelefs, remark, that phofphuret This phofphuree
of fulphur Like all other fubjfances hitherto employed for IR
eudiometry, cannot be .abfolutely depended upon for af- tion of changing
certaining the abfolute quantity of oxigen, contained in a the refidue.
given portion of atmofpheric air. For as foon as the abforp-
tion of oxigen is compleated, the remaining nitrogen exercifes
an aétion upon the phofphorus, by means of which its bulk
becomes increafed. From a number of experiments made with
that’ view with this eudiometrical fubftlance, I am led to The change is
believe that the volume of nitrogen gas, never increafes fo tae <4
much as to 7 part; confequently the bulk of the refiduum,
diminifhed by 4; gives us the bulk of the nitrogen gas of the
air examined; which bulk fubtraéted from the original mafs
of air, indicates the proportion of oxigen gas contained in it.
Phofphuret of. fulphur of the above compofition alfo de- This phofphuret
compofes nitrous acid with uncommon rapidity at common ks
temperatures. If one part of phofphuret of fulphur be in- rapidly,
troduced in the cold into four or fix of concentrated nitrous
acid, a violent aé@tion takes place, the acid is decompofed,
and both the phofphorus and fulphur are oxigenized, at the
expenfe of the oxigen of the nitric acid. A clear folution is
obtained, from which phofphoric and fulphuric acid may be
feparated in the ufual manner.
Phofphuret of fulphur is foluble in expreffed or fat oils, Mit eee us
one part of this compound, freed from adhering moifture as Hs mes * ;
much as poffible, be triturated ina Wedgwood’s mortar, with
fix parts of oil of almonds or olives, a liquid phofphorus is
obtained, which is far fuperior to that produced in the ufua]
manner from mere phofphorus. This liquid phofphorus fhines
and gives a very fine liquid phofphorus, with a beautiful yellow
light. It may be rubbed over the face, hands, &c. without
injury,
a
6 COMPOUND: OF SULPHUR AND FHOSPHORUS, ~
injury, provided the fluid be perfeéty tranfparent, and con-
fequently contains not a particle of phofphuret of fulphur me-
chanically fufpended. \
Which is un- The luminous property of this liquid phofphorus is fo con-
commonly lu- ¢ derable, that about 40z. of it, when contained in a common
ih a fize wine decanter, gives a fufficient light to difcern objects at
a confiderable difiance ina largeroom, the moment the decan-
ter is unftopped.
Beautifulex- | Equal parts of this liquid phofphorus and oil of turpentine,
ae * when agitated together and poured out of any convenient per-—
shower. forated veffel; exhibits a beautiful phenomenon, greatly re-
fembling a luminous rain, or fhower of fire.
Caution againt = =Though a liquid phofphorus may be obtained, as direéted
ee before, no attempt fhould be made to apply heat to a mixture
of phofphuret of fulphur. For an explofion was always the
refult whenever I attempted any procefs of that kind.
Phofphuret of —§ = Phofphuret of fulphur is foluble in fulphuric and nitric ether,
ee If either of thefe fluids be fuffered to ftand for fome weeks,
over a quantity of phofphuret of fulphur in a clofed vial; part
Luminous phe- of the compound becomes diffolved inthe ether. If the ether
eee be fuffered to evaporate fpontaneoufly, or when aflifted by
heat, a multitude of exceedingly fmall cryftals are left behind,
which fhine in the dark with a brilliant yellow light. A piece
of cloth dipped into this ether appears luminous in the dark all
over, but in a few minutes this luminous appearance ceafes,
and the whole appears to be fprinkled over with gems. If a
feather, or piece of tow, be dipt in water, and then thrown
into a bottle containing ether impregnated with phofphuret of
fulphur; at the moment of contaét of the two fluids, a fudden
light of a yellow colour f{preads through the air, undulates along
the furface of the fluid, and illuminates the whole bottle. —
Phofphuret of | Phofphuret of fulphur is foluble in pure or re@tified oil of
Saga turpentine, oil of rofemary, oil of lavender, and in the reft of
other volatile the volatile oils met with in commerce. The folutions are all
oils. luminous in the dark, and depofit the phofphuret of fulphur
when flowly evaporated, in the form of needlé-fhaped cryftals.
Sparingly in Highly reétified alcohol takes upa fmall quantity of phofphuret
alcohol. of fulphur, the alcolic folution is decompofable by the addition
of water.
It takes fire in hofphuret of fulphur takes fire fpontaneoufly in oxigenized —
ox. mur. acid
os muriatic acid gas, If afmall quantity of dry phofphuret of ful-
phur
COMPOUND OF SULPHUR AND PHOSPHORUS. 7
phur be introduced into a metallic fpoon, and then immerfed
in a bottle filled with oxigenized muriatic acid gas; the com.
pound inftantly kindles and burns with great vividnefs. The
refults of this experiment of courfe are phofphoric, fulphuric,
and muriatic acids.
Phofphuret of fulphur, when in a ftate of inflammation burns When already
alfo in nitrous gas, and in gafeous oxide of nitrogen. ) pe aes
If a piece of cotton be impregnated with phofphuret of ful- nitrous gas and
phur, and then furrounded with wool or tow, and placed un- peep 6s
der the receiver of an air-pump, the compound fhines with a Combuttion in
beautiful yellow light, which increafes in proportion as the air pre snie
is more rarefied, On re-admitting a {mall portion of air, Deana:
beautiful Corona or Aurora Borealis pervades the receiver. [f performed on
a thermometer be included into the cotton containing the phof- mac aks We
phuret of fulphur, it rifes in proportion as the light increafes,
and in this refpeét, as well asin the former, the phofphuret of
fulphur anfwers better for this experiment, which was firft no.
ticed by Van Marum, who made ule of phofphorus.
The formation of phofphuret of fulphur feems not to be at- No heat is de-
: We veloped when
tended with any change of temperature, as is {aid to be always the combination
the cafe in all chemical combinations whatever. For if the of phofphorus
‘phofphorus and fulphur be immerfed in heated water, at a dif. pe ea *
tancé from each other, together with a thermometer, no in-
creafe or decreafe of temperature could be obferved by means
of the moft delicate inftrument. The compound of phofpho- Itis more poi-
rus and fulphur aéts more violently in deftroying animal life, teas
than phofphorus alone. A cat which had eaten two grains of
phofphorus repeatedly without impunity, died within half an
hour after having {wallowed one grain of phofphuret of ful-
phur.
Old Compton-Street, Soho,
Auguft 16, 1803,
II. Obfervations
Mercury neatly
defined.
Great magnie
fying power not
fuitable to the
fun.
TRANSIT OF MERCURY,
II.
(Concluded from Page 304. Vol. V )
Objfervations of the Tranfit of Mercury over the Dyk of the Sun ;
to which is added, an Inveftigation of the Caufes which often
prevent the proper Aétion of Mirrors.. By Wittiam HER-
seurn; LLiD.fy ROS:
Wirs a 10-feet refleGtor, and magnifying power of 130, I
faw the corrugations of the luminous folar furface, up to the
very edge of the whole periphery of the difk of Mercury.
10" 27’. When the planet was fufficiently advanced towards
the largeft opening of the northern zone, I compared the in-
tenfily of the blacknefs of the two objeéts; and found the difk
of Mercury confiderably darker, and of a more uniform black
tint, than the area of the large opening,
10" 32’. The preceding limb of Mercury cuts the luminous
folar clouds with the moft perfeét fharpnefs ; whereas, in the’
great opening, the defcending parapet, down the ipa
fide, was plainly vifible.
It fhould be remarked, that the inftrument here applied to
the fun, with the moderate power of 130, is the fame 10-feet
reflector which, in fine nights, when direéted to very minute
double ftars, will fhow them diftin@ly with a magnifier of
1000.
Having often attempted to ufe high magnifiers in viewing
the fun, I withed to make another trial; though pretty well
affured I fhould not fucceed, for reafons which will appear
hereafter.
With two fmall double convex lenfes, both made of dark
green glafs, and one of them having the fide which is neareft
the eye thinly fmoked, in order to take off fome light, I viewed
the fun. Their magnifying power was about 300; and I faw
Mercury very well defined; but that complete diftinétnefs,
which enables us to judge with confidence of the condition
of the obje& in view, was wanting.
With a fingle eye-glafs, {moked on the fide towards the eye, |
and magnifying 460 times, I alfo faw Mercury pretty well
defined; but here the fun appeared ruddy, and no very mi-
pute objeéts could be perceived,
11"
TRANSIT OF MERCURY. i 9
11" 28’, The planet having advanced towards the pre- Obfervations of
ceding limb of the fun, it was now time to attend to the ap- the contacts.
pearances of the interior and exterior contacts.
11" 32’. 10-feet reflector. The whole difk of Mercury is as Not the leat
fharply defined as poffible ; there is not the leaft appearance 18" 1 any
of any atmofpheric ring, or different tinge of light, vifible about Mercury.
about the planet.
1)" 37’.. Appearances remain exaétly as before.
11 42’, The fharp termination of the whole mercurial difk,
appears to be even more ftriking than before. This may be
owing to its contraft with the bright limb of the fun, which,
having many luminous ridges in the northern zone, is remark-
ably brilliant about the place of the planet.
11* 44’, I was a few moments longer writing down the At Pt Ee
above than I fhould have been, to fee the interior contaét fo ae eels
completely as I could have wifhed; however, the thread of the fun’s limb
light on the fun’s limb was but juft breaking, or broken; but eee ant
no kind of diftortion, either of the limb or of the difk of Mer-
cury, took place. |
The appearance of the planet, during the whole time of its nor daring the -
paeeive from the fun, remained well defined, to the Te a a
aft.
The following limb of Mercury remained fharp till it reached
the very edge of the fun’s difk ; and vanifhed without occa-
fioning the fmalleft diftortion of the fun’s limb,: in going off,
or fuffering the leaft alteration in its own figure.
As foon as the planet had quitted the fun, the ufual appear-
ance of its limb was fo inftantly and perfeétly reftored, that not
the leaft trace remained whereby the place of its difappearance
could have been diftinguifhed from any other adjacent part of
the folar difk.
It will not be amifs to add, that very often, during the tranfit, No figns of
I examined the appearance of Mercury with a view to its” culate Meare
figure, but could not ‘perceive the leaft deviation from a fphe-
rical form; fo that, unlefs its polar axis fhould have happened
to be fituated, at the time of obfervation,; in a line drawn from
the eye to the fun, the planet cannot be materially flattened at
its poles,
OBGERVATIONS
10
The attion of
reflecting tele-
{copes is very
different at dif-
ferent times.
Whether moif-
ture in the air
impedes the
action of tele-
fcopes.
TRANSIT OF MERCURY.
OBSERVATIONS AND EXPERIMENTS RELATING TO THE
CAUSES WHICH OFTEN AFFECT MIRRORS, SO AS TO
PREVENT THEIR SHOWING OBJECTS DISTINCTLY.
It is well known to aftronomers, that telefcopes will at very -
differently at different times. The caufe of the many difap-
pointments they may have met with in their obfervations, is
however not fo well underftood.
Sometimes we have feen the failure afcribed to certain tre-
mors, as belonging to fpecula; and remedies have been pointed
out for preventing them. Not unfrequently again, the tele-
fcope itfelf has been condemned ; or, if its goodnefs could not
admit of a doubt, the weather in general has been declared
bad, though poffibly it might be as proper for diftinét vifion as
any we can expect in this changeable climate.
The experience acquired by many years of obfervation, will
however, I believe, enable me now to affign the principal
caufe of the difappointments to which we are fo often expofed.
Unwilling to hazard any opinion that is not properly fupported
by faéts, I fhall have recourfe to a collection of occafional ob-
fervations. ‘They have been made with fpecula of undoubted
goodnefs, fo that every caufe which impeded their proper ac-
tion muft be looked upon as extrinfic. I fhall arrange thefe
obfervations under different heads, that, when they have been
related, there may remain no difficulty to draw a few general
conclufions from them, which will be found to throw a con-
fiderable light upon our fubjeé.
Moifture in the Air.
(1.) O€tober 5, 1781. I fee double ftars, with 460, com-
pletely well. The air is very damp.
(2.) Nov. 23, 1781. 15" 30’, The morning is uncom.
monly favourable, and I fee the treble ftar Cancri, with 460,
in high perfeétion. The air is very moift, and intermixed with
paffing clouds.
(5.) Sept. 7, 1782. I viewed the double ftar preceding
12 Camelopardalis,* with 932, In this, and feveral other
fine nights which I have lately had, the condenfing moifture
on the tube of my telefcope has been running down in ftreams ;
which proves that damp air is no enemy to good vifion.
* See Phil. Tranf, Vol. LXXV. Part I, page 68; II. 53.
(4.) Dec,
‘TRANSIT OF MERCURY. J]
- (4.) Dec. 28, 1782. 17° 30’. The water condenfing on
my tube keeps running down; yet I have feen very well all
night. I was obliged to wipe the objeét-glafs of my finder
almoft continually. The fpecula, however, are not in the leaft
affeéted with the damp. The ground was fo wet that, in the
morning, feveral people believed there had been much rain in
the night, and were furprifed when I affured them there had
not been a drop. .
(5.) Feb. 19, 1783. I have feen perfeétly well till now *
that a froft is coming on; though Datchet Common, which is
juft before my garden, is all under water; and the grafs on
which I ftand with my telefcope is as wet as poffible.
(6.) Feb. 26, 1783. All the ground is covered with {now ;
yet I fee remarkable well.
{7.) March 8, 1783. The common before my garden is all
under water; my telefcope is running with condenfed vapour ;
not a breath of air ftwring. I never faw better. |
(8.) Auguft 25, 1783. My telefcope ran with water all
the night. The fmall fpeculum, which fometimes gathers
moifture, was never affeéted in the 7-feet tube, but was a little
fo in the 20-feet. The large eye-glaffes and objeé-glaffes of
the finders, required wiping very often. I faw all night re-
markably well.
Fogs.
(9.) O&. 30, 1779, It grows very foggy, and the moon is Whether fogs
furrounded with ftrong nebulofity ; neverthelefs, the ftars are oe a
very diftiné, and the telefcope will bear a confiderable power. tele{copes.
(10.) Auguft 20, 1781. It is fo foggy that I cannot fee an
objeé at the diftance of 40 feet; yet the ftars are very diftine
in the telefcope. By an jive of the fog, « Pifcium can no
longer be feen by the eye; yet, in the telefcope, it being dou-
ble, I fee both the ftars with perfeét diftinétnefs,
(11.) Sept. 6, 1781. A fog is come on; yet I fee very
well.
(12.) Sept. 9, 1781. There is fo ftrong a fog, that hardly
a ftar lefs than 30° high is to be feen ; and yet, in the tele-
{cope, at great elevations, I fee extremely well.
* The time is not marked in the journal; but, from the number
of the obfervations that had been made during the night, it muft
have been towards morning.
(13.) March
Whether froft
be an impedi-
ment to diftinét
vifion by tele-
fcopes.
TRANSIT OF MERCURY,
(13.) March 9, 1783. It is very foggy; yet in the telee
fcope I fee the flars without aberration, and they are very
bright. « Serpentarii is without a fingle ray.
(14.) April 6, 1783. A very thick fog fettles upon all my
glaffes; but the {pecula, even the 20-feet, which has fo large a
furface, remained untouched. I fee perfeétly well.
Froft.
(15.) Nov. 15, 1780; five o’clock in the morning. An
excellent {peculum, No. 2, will not aét properly; the frofty
morning probably occafions an alteration in its figure. An--
other fpeculum, No. 1, aéts but indifferently, though I have
known it to fhew very well formerly in a very hard froit: for
inftance, November 23, 1779, I faw with the fame mirror,
and a power of 460, the vacancy between the two flars of the
double ftar Caftor, without the leaft aberration.
(16.) O&. 22, 1781. Froft feems to be no hindrance to
perfect vifion. The tube of my 7-feet telefcope is covered
with ice; yet I fee very well.
(17.) Nov. 19, 1781. It freezes very hard, and the ftars,
even thofe which are 50° high, are very tremulous. I fufpeét
their apparent diameters to be diminifhed ; and, if I recolleé&
right, this is not the firft time that fuch a fufpicion has occurred
to me.
(18.) Jan. 10, 1782. My telefcope would not aét well, even
at an altitude of 70 or 80 degrees. There is a ftrong froft.
(19.) Jan. 31, 1782. I cannot fee with a power of 460,
the flars feem to dance fo unaccountably, and yet the air is
perfectly calm : even at 60 or 70 degrees of altitude, vifion is
impaired,
(20.) Feb, 9, 1782. That froft is no hindrance to feeing
well is evident ; for, not only my breath freezes upon the fide
of the tube, but more than once have I found my feet faftened
to the ground, when I have looked long at the fame ftar.
(21.) OG. 4, 1782. It froze very feverely thisnight. At
firft, when the froft came on, I faw very badly, every object
being tremulous; but, after fome time, and at proper altitudes,
I faw as well as ever. Between five and fix o’clock in the
morning, objects began to be tremulous again ; occafioned, I
fuppofe, by the coming on of a thaw.
(22.) Jan,
TRANSIT OF MERCURY. 13
‘
(22.) Jan. 1, 1783. I made a number of delicate obferva-
tions this night, notwithftanding, at four o’clock in the morn-
ing, my ink was frozen in the room; and, atabout five o’clock,
a 20-feet {fpeculum, in the tube, went off with a crack, and
broke into two pieces. On looking at Fahrenheit’s thermo-
meter, I found it.to ftand at 112.
(23.) May 6, 1783. It freezes, and in the telefcope the
flars feem to dance extremely.
Hoar-froft.
(24.) Nov. 6, 1782. There isa thick hoar-froft; yet I fee Hoar froft ; its
extremely well. It feems to enlarge the diameters of the ftars ; ae be
buat, as I fee the minuteft double ftars well, the apparent en-
largement of the diameters muft be a deception.
(25.) Dec. 22, 1782. There is a ftrong hoar-froft: gather-
ing upon the tubes of my telefcopes ; but I fee very well. .
Dry Air.
(26.) Dec. 21, 1782. The tube of my telefcope is dry, Dry air inimical
and I do not fee well. bs talbott hes
; by telefcopes.
(27.) April 30, 1783. The ftars are extremely tremulous *
and confufed ; the outfide of the tube of my telefcope is quite
dry.
Northern Lighis.
(28.) Sept. 25, 1781. There are very firong northern Northern lights
lights; their flafhing does not feem to interfere with tele- 4° 2°t fem to
‘ 4 y impede vifion by
feopic vifion; but all objeéts appear tremulous, and indif- telefcopes.
ferently defined.
(29.) Aug. 30, 1782. There are very bright northern
lights, in broad arches, with white ftreaks; yet I fee perfeétly
well.
(30.) March 26, 1783. An Aurora Borealis is fo bright,
that » Herculis, which it covers, can hardly be feen; yet, in -
the telefcope, and with a power of 460, I find no difference.
I compared the ftar with y Coronz, which was ina bright
part of the heavens, and in the telefcope they appeared nearly
alike. I fufpeéted » Herculis te be fomewhat. more tinged
with red than it fhould be; and examined it afterwards, when
clear of the Aurora: it was indeed lefs red; but, as it had
gained more altitude, the experiment was not decifive.
: Windy
14 TRANSIT OF MERCURY.
Windy Weather.
Wind impairs (31.) Jan. 8, 1783. Itis very windy. The diameters of
the effect of the ftars are ftrangely increafed, even thofe at 60 and 70° of
telefcopes.
altitude. Every ftar feems to be a little planet.
(32.) Jan. 9, 1783. Wind increafes the apparent diameters
of the ftars.
(33.) Sept. 20, 1783. The night has been very windy ;
and I do not remember ever to have feen fo ill, with fuch a
beautiful appearance of brilliant ftar-light.
Fine in Appearance.
Weather appa- (34.) May 28, 1781, The evening, though fine in ap-+
1S Saag pearance, is not favourable. No inftrument I have will aé
properly. The wind is in the eaft.
(35.) Auguft 30, 1781. The ftars appear fine to the naked
eye, fo that I can fee « Lyrz very diftinétly to be two ftars ;
yet my telefcope will fhow nothing well. There are flying
clouds, which, by their rapid motion, indicate a difturbance in
the upper regions of the air; though, excepting now and then
a few gufts of wind, itis in general very calm. Ata diftanee
there are continual flafhes of lightning, but I can hardly hear
any thunder.
(36.) Sept. 14, 1781. I fee very fmall ftars with the naked
eye; but the telefcope will not aé fo well as it fhould.
(37.) Sept. 24, 1781. The evening is apparently fine; but,
with the telefcope, I can fee neither n Corone nor Bootis
double ; nor indeed can I fee any other ftars well.
Over a Building.
Vicinity of a (38.) Auguft 24, 1783. I viewed « Bootis with 449,737,
building renders ang 910, but faw it very indifferently. The ftar was over a
the ftars indif-
ting; houle.
(39.) O@. 26, 1780. « Bootis being near the roof of »
houfe, I faw it not fo diftin€ly as I could wih.
The Telefcope lately brought out.
Recentexpofure (40.) O&. 10, 1780. 6° 30’. Having but juft brought out
of the telefcope lake itowall & well
does notafford. M™MY telelcope, it will not act weil,
diftin&nefs. 6" 45’, The tube and fpecula are now in order, and per-
form very well.
| 2 (41.) Jan.
TRANSIT OF MERCURY. 13
(41.) Jan. 11, 1782, To all appearance, the morning
was very fine, but ftill the telefcope, when firft brought out,
would not a& well. After half an hour’s expofure, it performed
better.
Confined Place.
(42.) July 19, 1781. 13°15’. My, telefcope would not aét A confined place
well; and, fuppofing the exhalations from the grafs in my Prevents tele-
{copes from
garden to affe& vifion, I carried the telefcope into the ftreet, aéting well.
(the obfervation was made at Bath,) and found it to perform
to admiration.
(43.) July 19, 1781. My telefcope aéted very well; but
a flight field-breeze fpringing up, and brufhing through the
ftzeet where my inftrument was placed, it would no longer
bear a magnifying power of 460.
Hazinefs and Clouds.
(44.) Sept. 22, 1783. The weather is now fo hazy, that Remarkable
the double ftar 3 Cygni is but barely vifible to the naked 2 Seay gees
This has taken off the rays of the large ftar, fo that I now fee
the fmall one extremely well, which at other times it is fo dif-
ficult to perceive, even with a magnifying power of 932.
(45.) Auguft 13, 1781. A cloud coming on very gradually
upon fixed ftars, has this remarkable effeét, that their apparent
diameters diminifh gradually to nothing.
(46.) July 7, 1780. The air was very hazy, but extremely
calm. I had Aréturus in the field of view of the telefcope,
and, the hazinefs increafing, it had a very beautiful effect on
the apparent diameter of this ftar, For, fuppofing the firft of One caufe of the
the points *, to reprefent the magnitude when brighteft, 15 el
faw it gradually decreafe, and affume, with equal diftin€tnefs, ars,
the form of all the fucceeding points, from No. 1 to No. 10,
in the order of the numbers placed over them. The laf
magnitude I faw it under, could certainly not'exceed two-
tenths of a fecond; but was perhapslefs than one. This leads
to the difcovery of one of the caufes of the apparent magnitude
of the fixt ftars, |
* Thefe points will be inferted in one of the plates in our next
number. N.
Focal
16 TRANSIT OF MERCURY.
Focal Length.
Obfervations in (47.) Nov. 14, 1801. The focal length of my 10-feet
sae! mh ‘eS mirror increafes by the heat of the fun. I have often obferved
of the fpeculum this before; the difference, by feveral trials, amounts to 8
= by hundredths of an inch. |
(48.) Dec. 13, 1801. The focal length of my 10-feet
mirror, while I was looking at the fun, became fhorter, con-
trary to what it ufed to do; but, there being a ftrong froft, I
guefs that the objeét metal grows colder, notwithftanding its
expofure to the fun’s rays.
(49.) Nov. 9, 1802. 10° 50’. The focus of my 7-feet glafs
mirror became 18 hundredths of an inch fhorter, on being ex-
poled for about a minute to the fun. The figure of the {pe-
culum was alfo diftorted; the foci of the infide and outfide
rays differing confiderably, though its curvature, by obferva-
tions on the ftars, has been afcertained to be ftriétly parabo-
lical.
12°0, The fame mirror, expofed one minute to the action
of the fun, became 21 hundredths fhorter in focal length.
The focus of a 10-feet metalline mirror, when expofed one.
minute to the fun’s rays, became 15 hundredths of an inch
longer than it was before.
(50.) January 9, 1803. When I looked with the glafs 7-
feet mirror, feveral times, a minute or two at the fun, it fhort-
ened generally ,24, ,26, and ,30 of an inch, in focal length.
The obfervations which are now before us, appear to be
fuflicient to eflablit the following principle; namely,
General prin- «That in order to fee well with telefcopes, it is required
ciple. Uniform that the temperature of the atmofphere and mirror fhould be
temperatures an is icy» Aerie ;
moifture in the uniform, and the air fraught with moifture.”
air are requifite This being admitted, we fhall find no difficulty in account-
a li ing for every one of the foregoing obfervations.
This doerine If an uniform temperature be neceflary, a froft after mild
applied to, weather, or a thaw alter froft, will derange the performance of
our mirrors, till either the froft or the mild weather are fufi-
ciently fettled, that the temperature of the mirror may accom~
apeen etnies modate itfelf to that of the air. For, till fuch an uniformity
of teeperature; with the open air, in the temperature of the mirror, the tube,
the eye-glafies, and I would almoit add the obferver, be ob-
tained, we cannot expeét to fee well. See obfervation 15,
47, 18, 19, and 23,
But
YRANSIt OF MERCURY, 17
Bat, when a froft, though very fevere, becomes [ettled, the
mirror will foon accommodate itfelf to the temperature; and
we fhall find our telefcopes to aét well. See obfervation 16,
20, 21, 22, 2%, and 25.
_ This explains, with equal facility, why no telefcope juft or of expofure ;
brought out of a warm room can a properly. See obferva-
tion 40 and 41.
Nor can we ever expedi to make a delicate obfervation, obfervations
with high magnifying powers, when looking through a door, °™ 4 confined
‘ piace 5
window, or flit in the roof of an obfervatory ; even a confined
place, though in the open air, will be detrimental. See obfer-
vation 42 and 43.
It equally thows, that windy weather in general, which-muft windy weather ;
occafion a mixture of airs of different temperatures, cannot be
favourable to diftin@ vifion. See obfervation 31, 32, and 33. »
The fame remark will apply to Aurore Boreales, when they aurorze boreales ;
induce, as they often do, a confiderable change in the tempera-
ture of the different regions of air. See obfervation 28.
But, fhould they not be accompanied by fucha change, there
feems to be no reafon why they fhould injure vifton. See obs
fervation 29 and 30.
The warm exhalations from the roof of a houfe in a cold the roof ofan
night, muft difturb the uniformity of the temperature of a {mall houfe 5 f
portion of air; fo that ftars which are over the houfe, and
at no confiderable diftance, may be affected by it. See obfer.
vation 38 and 39.
Sometimes the weather’ appears to be fine, and yet our tele- weather anpae
fcopes will not a& well. . This may be owing to drynefs occas tently fines
fioned by an eafterly wind; or to a change of temperature,
arifing from an agitation of the upper regions of the atmofphere.
See obfervation 34 and 35.
Or, poflibly, to both thefe caufes combined together, See
obfervation 36 and 37.
If moifture in the atmofphere be neceflary, dry air cannot
be proper for vifion. See obfervation 26 and 27. ©
And therefore, on the contrary, dampnefs, and hazinefs of damps, haze;
the atmofphere, muft be favourable to diftin@ vifion. See
obfervation 1, 2, 3, 4, 6, and 8.
Fogs alfo, which certainly denote abundance of moifture, fogs SCs
muft be very favourable to diftinét vifion. See obfervation 9,
105 1, 12, 13, and 14,
Vor. VI.—SerremsBer, C Nay,
18
Experiments on
the change of
focal length in
mirrors: by heat.
TRANSIT OF MERCURY.
Nay, if the obfervatory fhould be furrounded by water, we
need be under no apprehenfion on that account. Perhaps,
were we to ereét a building for aftronomical purpofes only, we
ought not to objeét to grounds which are occafionally flooded ;
the neighbourhood of a river, a lake, or other generally called
damp fituations. See obfervation 5 and 7.
It is however poffible, that fogs and hazinefs may increafe
to {uch a degree as, at laft, to take away, by their interpofition,
all the light which comes from celeftial objeéts ; in which cafe,
they muft of courfe put an end to obfervation ; but they will
neverthelefs be accompanied with diftiné vifion to the very
laft. See obfervation 44, 45, and 46.
We have now only the four laft obfervations to account for.
They relate to the change of the focal length of mirrors in
folar obfervations, and its attendant derangement of the foci of
the different parts of the refleGting furface; and, as fimplicity
is one of the marks of the truth of a principle, I believe we need
not have recourfe to any other caufe than the change of tem-
perature produced by the aétion of the folar rays that occafion
heat; which will be quite fufficient to explain all the pheno-
mena. But, in order to fhow this in its proper light, I fhall
relate the following experiments.
Wis Experiment.
I placed a glafs mirror, of 7-feet focal length, in the tube
belonging to the telefcope; and, having laid it open at the
back, I prepared a ftand, on which the tron ufed in my expe-
riments on the terreftrial rays that occafion heat (fee Phil.
Tranf. for 1800, Plate XVI. Fig. 1.) might be placed, fo as to
heat the mirror from behind, while I kept a certain objeét in
the field of view of the telefcope. Having meafured the focal
length, and alfo examined the figure of the mirror, which was
parabolical, the heated iron was applied fo as to be about 23
inches from the back of the glafs mirror. The confequence of
this was, that a total confufion in all the foci took place, fo that
the letters on a printed card in view, which before had been
extremely diftin€t, became inftantly illegible. In 15 feconds,
the focus of the mirror was fhortened 2,3 inches; in half a
minute, 3,47 inches; and, at the end of the minute, I found
it no Jefs than 4,59 inches fhorter than it had been before the
application of the hot iron.
On
TRANSIT OF MERCURY,
19
On repeating the experiment, but placing the heated iron no pyperiments on
more than 2 of an inch from the back of the mirror, its focal the chan&¢ of
length, in 12 minute, became 5,33 inches fhorter.
I tried ail a more moderate heat; and, placing the iron at
3 inches from the back, the focus of the mirror fhortened in
one minute 2,83 inches.
A thermometer placed in contaé ail the refleGting furface
of the mirror, could hardly be perceived to have rifen, during
the time in which the hot iron produced the alteration of the
focal length.
2d Experiment.
Every thing remaining as before, I fufpended a fmall globe
of heated iron in front of the mirror, at one inch and a half
from its vertex ; and, in two minutes, the focus was lengthened
5,3 inches. The figure of the mirror. was alfo deranged ; fo
that the letters on the card could not be diftinguifhed.
I made a fecond trial, with the fufpended iron a little more
heated, and brought it as near the furface of the mirror as I
judged it to be fafe; fince a contaét would probably have
cracked the mirror. In confequence of this arrangement, the
focus lengthened, in one minute, 1,64 inch.
On removing the heated iron, the mirror returned, in one
minute, to within ,18 inch of its former focal length; and, at
_ the end of the fecond minute feemed to be nearly reftored. But
_ the difagreement of the foci of the different parts of the re-
fle€ting furface might be perceived for a long time afterwards,
and caufed an indiftinétnefs of vifion, which plainly indicated
that, under fuch circumftances, the magnifying power of the
telefcope, 225, was more than it ought to be, in order to fee
well.
3d Experiment.
I now changed the glafs mirror for a metalline one; and, on
placing the heater near the back of it, the focus of the fpecu-<
lum, in 30 feconds, became ,77 inch fhorter. But, conti-
nuing the obfervation, inftead of fhortening ftill farther in the
next 30 feconds, it became ,3 inch longer, fo that, at the end
of a minute, it was only ,47 fhorter than before the approach
of the hot iron.
C2 4th Expe-
focal length in
mirrors by heats
20
Experiments on
the change of
focal length in
TRANSIT OF MERCURY.
4th Experiment.
When the fmall heated globe of the 2d experiment was
fufpended in front of the mirror, the focus lengthened ,27 inch
"mirrors by heat. in one minute; nor would the lengthening increafe by leaving
the hot iron longer in its pofition. The foci in this, as well as
in the 3d experiment, were fo much injured that they could
not be meafured with any precifion ; and it was evident, that
high magnifying powers ought not to be ufed with a mirror of
which the temperature is undergoing a continual change.
I repeated the experiment with the iron nearly red hot; and
found the focus lengthened 1,48 inch in $0 feconds. Five
minutes after the removal of the iron, the regularity of the
figure of the mirror was pretty well reftored.
With a moderate heat, I had, in 30 feconds, a lengthening
of the focus, of ,57 inch; and, in about 14 minute after the
removal of the heated iron, diftinét vifion was nearly reftored.
Thefe four experiments fhow, that a change in the tempera-
ture of mirrors, occafioned by heat, is attended with an altera-
tion of their focal Jength ; and alfo prove, that the figure of the
reflecting furface is confiderably injured, during the time that
fuch a change takes place. We areconfequently authorifed to
believe, that the {mall alteration in the focus of a mirror ex-
pofed to the rays of the fun, arifes from the fame caufe. For,
fince a thermometer, when the fun is fhining upon it, will fhow
that its temperature is altered, the adtion of the folar rays upon
a mirror muft be attended with a fimilar effe& in its tempera-
ture. See obfervation 47, 48, 49, and 50.
The fame experiments will now alfo explain why the obfer-
vations of the fun, related in oar tranfit of Mercury, between
10" 32’ and 11" 28’, were not attended with fuccefs; for we
have feen that heat occafions a derangement in the aétion of
the reflecting furface ; and it follows that, under fuch circum-
flances, high magnifying powers cannot be expected to fhow
objects very diftinéily.
If it thould be remarked, that I have not explained why the
focus of a glafs mirror fhould fhorten by the fame rays of the
fun which lengthen that of a metalline fpeculum, I confefs that _ -
this at prefent does not appear; and, as it is not material to
our purpofe, I might pafs it over in filence. We are however
2 pretty
! oy
TRANSIT OF MERCURY, 9}
pretty well affured, that the alterations of the focal length muft Experiments on
- be owing to a dilatation of the glafs or metal of which mirrors pa od
gth in
are made, and muft be greateft where moft heat is applied. mirrors by heats
Our experiments therefore cannot agree perfeétly with folar
oblervations ; for, in the glafs mirror, the application of partial
heat in front, muft undoubtedly have been much ftronger about
_the middle of the mirror (though the centre of it was fome-
times guarded by a brafs plate equal to the fize of the {mall
fpeculum) than at the circumference. But when, on the con-
trary, a mirror is expofed to the fun, every part of the furface
will receive an equal portion of heat.
It may alfo be faid, that I have pointed out a defeét in tele.
fcopes ufed for folar obfervations, without afligning a cure for
it. It will however be allowed, that tracing an evil to its caufe
muft be the firft ftep towards a remedy. Had the imperfec-
tion of the figure brought on by the heat of the folar rays been
of a regular nature, an elliptical fpeculum might have been
ufed to countera€&t the affumed hyperbolical form; or vice
verfa. i
And now, as, properly fpeaking, the derangement of the
figure of a mirror ufed in obferving the fun, is not fo much
caufed by the heat of its rays as by their partial application to
the refleGting furface only, which produces a greater dilatation
in front than at the back, there may be a poffibility of counter-
aéting this effeét, by a contrary application of heat againft the
back, or by an interception of it on the front, But this we
leave to future experiments.
Ill.
Obfervations on the Chemical Nature of the Humours of the Eye.
By Ricuarp Cuenevix, Lg. FR. S. and M. kt. I. A.*
‘Tue funétions of the eye, fo far as they are phyfical, have
been fuund fubjeét to the common laws of optics. It cannot be
expected that-chemiftry fhould clear up fuch obfcure points of
phytiology, as all the operations of vifion appear to be ; but,
fome acquaintance with the intimate nature of the fubftances
* From the Philofophical Tranfactions, 1803.
which
92 3h NATURE OF THE HUMOURS ON THE EYE.
which produce the effects, cannot fail to be a ufeful appendage
toa knowledge of the mechanical ftru€ture of the organ.
Humours of the The chemical hiftory of the humours of the eye, is not of
eye little known much extent. The aqueous humour had been examined by
chemically. : i if : 5
Aqueous Bertrandi; who faid, that its fpecific gravity was 975, and
humours therefore lefs than that of diftilled water. Fourcroy, in his
Syftéme des Connoissances chimiques, tells us, that it has a faltifh .
tafte ; that it evaporates without leaving a refiduum ; but chat
-it contains fome animal matter, with fome alkaline phofphate
and muriate... Thefe contradi@ions only prove, that we have
no accurate knowledge upon the fubjeé.
Vitreous The vitreous humour is not better known. Wintringham
es has given its fpecific gravity (taking water at 10000) as equal
to 10024; but I am not acquainted with any experiments to
inveftigate its chemical nature.
Cryftalline lens. We are told by Chrouet, that the cryftalline lens affords,
by deftruétive diftillation, fetid oil, carbonate of ammonia, and
water, leaving fome carbon in the retort. But, deftru@tive dif-
tillation, although it has given us much knowledge as to animal
matter in general, is too vague a method for inveftigating par-
ticular animal fubftances.
{ thall now proceed to mention the experiments I have made
upon all the humours. I fhall firft relate thofe which were made
upon the eyes of fheep, (they being the moft eafily procured,)
and fhall afterwards fpeak of thofe of the human body, and
other eyes. I think it right to obferve, that all thefe eyes were ©
as frefh as they could be obtained.
SHEEPS’ EYES.
Aqueous Humour.
Of theeps’ eyes; The aqueous humour is a clear tranfparent liquid, of the
The aqueous f{pecific gravity of 10090 *, at 60° of Fahrenheit. When frefh,
humour. Water, . A.
albumen, gela- it has very little {mell, or tafte.
tine and muriate It caufes very little change in the vegetable reactive colours ;
of foda. and this little would not, I believe, be produced immediately
after death. I imagine it to be owing to a generation of am-
monia, fome traces of which I difcovered,
* All thefe fpecific gravities are mean proportionals of feveral
experiments. The eyes of the fame fpecies of animal, donot differ
much in the Specific gravity of their humours,
When
NATURE OF THE HUMOURS OF THE EYE, 23
When expofed to the air, at a moderate temperature, it
evaporates flowly, and becomes flightly putrid.
When made to boil, a coagulum is formed, but fo fmall as
_hardly to be perceptible. Evaporated to drynefs, a refiduum
remains, weighing not more than 8 per cent. of the original
liquor.
Tannin caufes a precipitate in the frefh aqueous humour,
both before and after it has been boiled, and confequently fhows
the prefence of gelatine.
Nitrate of filver caufes a precipitate, which is muriate of
filver. No metallic falts, except thofe of filver, alter the
aqucous humour.
From thefe and other experiments it appears, that theaqueous
humour is compofed of water, albumen, gelatine, anda muriate,
the bafis of which I found to be foda.
[have omitted {peaking of the aétion of the acids, of the
alkalis, of alcohol, and of other re-agents, upon this humour.
It is fuch as may be expeéted in a folution of albumen, of
gelatine, and of muriate of foda,
Cryftalline Humour.
To follow the order of their fituation, the next of the humours Cry ftalline
‘is the cryftalline. os Much
. i . reer proportion
This differs very materially from the others. of albumen and
Its fpecific gravity is 11000. gelatine.
When frefh, it is neither acid noralkaline. It putrifies very
rapidly. It is nearly all foluble in cold water, but is partly
_ coagulated by heat. Tannin gives a very abundant precipitate ;
but I could not perceive any traces of muriatic acid, when I had
obtained the cryftalline quite free from the other humours. It
is compofed, therefore, of a f{maller proportion of water than
the others, but of a much larger proportion of albumen and
gelatine.
Vitreous Humour.
I preffed the vitreous humour through a rag, in order to free Vitreous
it from its capfules ; and, in that ftate, by_all the experiments )umeure, The
I could make upon it, I could not perceive any difference aqueous.
between it and the aqueous humour, either in its {pecific gravity,
(which I have found to be 10090, like that of the other), or
in its chemical nature,
M. Fourcroy
\
" Od, NATURE OF THE HUMOURS OF THE EYE.
No phofphatein MM. Fourcroy mentions a phofphate, as contained in thefe
thefe humours+ humours ; but I could not perceive any precipitation by muriate
or nitrate of lime; nor did. the alkalis denote the prefence of
any earth, notwithftanding M. Fourcroy’s affertion of that
~ fe
HUMAN EYE.
Human eye ; I could not procure a fufficient quantity of thefe, frefh enough
not chemically t Itin] \ : a" | ies Iyantth
different from 0 Multiply my experiments upon them. owever, by the
other eyes. affiftance of Mr. Carpue, Surgeon to his Majefty’s Forces, I
fully convinced myfelf, that the humours of the human eye,
chemically confidered, did not contain any thing different from
the refpe€tive humours of the eyes I had examined. ‘The
aqueous and vitreous humours contained water, albumen, gela-
tine, and muriate of {oda ; and the cryftalline humour contained
only water, albumen, and gelatine. The fpecifie gravity of
; ihe aqueous and vitreous humours, I found to be 10053; while
that of the cryftalline was 10790.
EYES OF OXEN.
So likewife the
I found the eyes of oxen to contain the fame fubftances as
eyes of oxen.
the refpeGtive humours of other eyes. The fpecific gravity of
the aqueous and viireous humours is 10088; and that of the
cryftalline 10765. ; ‘
Probable law ; What is particularly worthy of notice is, that the difference
that the {mailer : 3 z ”
Pee oye the eaote which appears to exift between the fpecific gravity of the
does the denfity aqueous or vitreous humour and that of the cryftalline, is much
er a greater in the human eye than in that of fheep, and lefs in the
ofthe other eye ef the ox. Hence it would appear, that the difference
humours. between the denfity of the aqueous and vitreous humour and
that of the cryftalline, is in the inverfe ratio of the diameter
of the eye, taken from the cornea to the optic nerve, Should
further experiments fhow this to be a univerfal law in nature,
it will not be poffible to deny that it is in fome degree defigned
for the purpofe of promoting diftinét vifion,
pare In taking the {pecific gravity of the aqueous and vitreous
euore delat - humours, no particular precaution is neceflary, except that they
_ approaching the ought to be as frefh as poffible. But the cryftalline humour is
os not of an uniform denfity throughout; it is therefore effential,
that attention be given to preferve that humour entire for this.
operation, I found the weight of a very’frefh cryftalline of an
Ox
,
NATURE OF THE HUMOURS OF THE EYE. 25
ex to be 30.grains; ‘and its fpecific gravity was, as I before
flated, 10765.. I then pared away all the external part, in
every direétion, till there remained but fix grains of the centre,
and the fpecific gravity of ihefe fix grains, I found to be 11940.
From this it would feem, that the denfity increafes gradually,
from the circumference to the centre. ~
It is not furprifing that the cryftalline humour fhould be Itis very fubjeé
fubjeé to diforders, it being wholly compofed of animal matter ree
of the moft perifhable kind. Fourcroy fays, that it is fome- lable nature.
times found offeous in advanced age. Albumen is coagulated
by many methods ; and, if we fuppofe that the fame changes
can take place in the living eye as in the dead animal matter
of the chemifts, it will be eafy to account for the formation of
the cataraét; a diforder which cannot be cured but by the
removal of the opaque lens. If a fufficient number of obfervas
tions were made refpeting the frequency of the cataraé in
gouty habits, fome important conclufions might be drawn, as
to the influence of phofphoric acid, in caufing the diforder,
by the common effect of acids, in coagulating albumen.
IV.
A Letter from Mr. Irvine concerning the late Dr. Invine, of
Glafgow, his Doétrine, which afcribes the Difappearance of
Heat, without Increafe of Temperature, to a change of Capacity
_ in Bodies, end that of Dr. Buack, which fuppojes Caloric to
become latent by Chemical Combination with Bodies ; with par-
ticular Remarks on the Miftakes of Dr. THomeson, in his °
Accounts of thefe DoGrines.
To Mr. NICHOLSON,
SIR,
In the article Chemiftry in the Supplement to the Encyclo- Account given
pedia Britannica, in moft refpeéts excellently written, I could? the Encycls
: ‘ : Britt. of the
not fail to be ftruck with the account there given of the theory jnveftigation of.
of heat, and the mode of inveftigating the natural zero adopted the zero of heats
by the late Dr. Irvine. Had Dr. Thompfon been indifputably
accurate in /és opinions, had a mathematically clofe argument
left no door for the entrance of doubt, he would fcarcely even
then
26 DR. IRVINE’S AND DR. BLACK’S
then have been juftified in the terms he has ufed. But here
we have every thing fettled, and we are informed with the
air of an ancient fophift, that it is examined and found infuf-
ficient. I am induced to make an,obfervation or two on this
examination, becaufe I am informed that the mathematical air
which reigns through this part of this work has actually im-
pofed on many. For this time, however, I believe it can be
fhewn that it is no more than an air, and that this fubje@ is
not yet finally fettled.
Dr. Thompfon’s. Dr. Thompfon fays, at page 269, Suppl. Ency, Brit. “ Dr.
2 Sania Irvine, of Glafgow, advanced a theory on this fubjec dif-
r. Irvine’s
theory of heat. ferent from that of Dr. Black. The fpecific caloric of water
That caloric —_ being greater than that of ice, it requires a greater quantity of
abforbed by ice pes Hee : : :
on its converfion Caloric to raife it to a given temperature than it does to raife
into iyi ice. The caloric therefore does not become latent, it only
aegis Soman feems to do fo from the greater fpecific caloric of water. This
rature) only theory was zealoufly adopted by Dr. Crawford. | Dr. Black
seca obferved very juftly, that it did not account for the produétion
really employed Of fluidity at all. The fpecific caloric of water is indeed
in keeping up the greater than that of ice; but how is the ice converted into
temperature
while the capa- Water? This is an objeGtion which the advocates for Dr.
eity is increafed; Iryine’s or Dr. Crawford’s theory, (as it has been improperly
eee called) will not catty antwen' oLet ine whether thi
doesitetexplain Calle ) will not eafily anfwer. Let us examine whether this ,
the aét of theory accounts for the apparent lofs of caloric. It follows -
ae from Mr. Kirwan’s experiments, that the fpecific caloric of
Dr. Thompfon. water is to that of ice as 10 to9. Dr. Black proved, that as
The capacity of much caloric entered the ice as would have raifed it had it been
is to tha : I
of ice “ ey water, 140°. Let us fuppofe that it would only have raifed
—Iceduring the ice 140; in that cafe the melted ice ought to have been of
fufion abforbs oo 7 ;
what would have the temperature of 158°, for 10:9::140: 126, but it was
raifed water only 32°, Therefore 126° of caloric have difappeared, and
| paar \ ° , “ce .
Bee ges eee cannot be accounted for by the change of fpecific caloric.
raiféd the ice at Nor can the accuracy. of Dr. Black’s experiment be fulpeéted ;
Jeaft as much if if has been repeated in every part of the world, and varied
3t had remained .
folid—whence in every poflible way. We cannot doubt, therefore, that
itis inferred caloric unites with fubflances, and caufes them to become
hat the fufed : sec : Nia, ante :
ide hee fluid, or that there is in fact a caloric of fluidity different from
eught tohave {pec fic caloric.”
ie Now nobody doubts Dr. Black’s experiment, and it is not
326%, ifthe neceflary to our argument to have any doubt on that fubjeét.
difference of : ; BN oN : a9
panty hid Dr. Thompfon gives it as a fair {tatement of Dr. Irvine’s thes
alone operated ory,
in the cafe;
THEORIES OF HEAT. ye
ery, that the 1403 entering ice during its change of forms, But it escatt
fhould be leffened in the ratio of 9: 10, and fhould therefore ea rea
be 126°, or in other words, if the heat entering the ice were the 126° of
only-enough to raife the ice 140°, that the temperature of the heat are con=
° ae beef fidered as having
water fhould be 158°. But it is eafy to fee that on this fup- beyond doubt
pofition the water would contain two portions ofheat, namely, ps5 By
* ages c t an
its original quantity from the natural zero to 32°, expreffed 5.57
in degrees according to the capacity of ice, and the fuperadded Reply. Dr.
4 : ‘ that Thompfon in his
portion from 32 to 158, expreffed in degrees according tO ne cm ent CPA
of water. The ice would no doubt according to this ftatement, change of capa-
become water without abforbing any heat, and the water “ty, attends to
i S the fuperadded
would be merely heated as in every other cafe. But Dr. Ir- je. only, and
vine, and after him Dr. Crawford, and the writers of ele- noah eet;
. t t
mentary treatifes for the laft fifteen years, and I believe I may esting apt a
venture to fay every one of our philofophers, except Dr. Thomp- body.
fon himfelf, have ftated this doétrine of capacities to be, that no ha
every one of the thermometrical degrees expreffing the whole We. Mien
of the heat contained in a body, are to be taken in proportion is nynitere but
c i ; 5 : re ‘Vhompfon
to its capacity ; and therefore that if the ice fuddenly changed rth, eer
its capacity, it would abforb not merely a rateable proportion the qwéole eat
of what heat might be prefented to it, but an abfolute quan. i 4 bedy ata
. ‘ s given temp€rae
tity to make up for its new capacity. For the heat neceffary ture as the mea-
to raife the temperature of ice each degree from natural zero, /ure of its capa~
. dis . tye
is to the heat neceflary to raife water each degree from the 4G
fame point as the capacity of the one body is to that of the
other. Ice cannot then as it acquires its new form, thew any Ice in fufion
augmentation of temperature till the differences between the 74/45 all the
F _ beat prefented te
heats of each degree from the loweft point be made up. Thisic until its ene
difference amounts to the 140° found by the experiment, and pan rime
. Keates rp 3 ished, an
cannot raife the water even the fraction of a degree in tempe- cannot till then
rature, becaufe it is barely fufficient for the demands of Big Pavan aac
new capacity. Had the 140° been applied to water, Dr. ‘“™Peratures
Thompfon’s affertion of the rife of temperature would have
been juft, but it can have no reference whatever to heat ap-
plied during a change of capacity.
The fame arguments are repeated in page 271, and the fame If the capacity
miftake reigns through the whole. Is it not obvious, that te eee
. : . . . uddeni -
you would inftantaneoufly increafe the capacity of any body, creafed iatees
it would immediately become colder, and its temperature fink perature would
as much lower as its new capacity was higher. In the fame ‘13
or it would cone
way, if a body has its capacity fuddenly increafed, and at the tinue ftationary
ame if due heat were
fam added 5
and this ts the
cafe with ice.
hence, &c, as
before.
The caufe of
fluidity afcribed
to the fame
ation of heat
which enlarges
the capacities of
bodies.
‘The experi-
ments on heat
ace moftly too
Inaccurate to
give the fame
depreffion for the
uatural zero,
DR. IRVINE’S AND DR: BLACK’S
fame time a quantity of heat added to it to make the whole
heat in proportion to its new capacity, furely that body would
continue exaétly at the fame thermometrical point. Now
melting ice is that body; the 140° are demanded by new capa-
city,—would have been more if its capacity had been greater,
and lefs if lefs. On the very principles therefore in difpute,
ice on becoming water ought to receive a quantity of heat,
and that quantity isnot governed by the proportion of 9 to 10,
but the whole heats are in that proportion, and the 140° is
only their difference. Fer all calculations on tke alteration of
temperature to be produced by a given portion of heat on a
body, from the knowledge of the relation of its capacity to
another, and of the number of degrees that other is railed by
the fame quantity, continue juft only while the capacities con-
tinue in the fame proportion.
Surely it is poffible to form a notion that heat (140°,) may
enter into water as the very caufe of fufion, fo ds to alter its
ftate and change its capacity ; that very heat making the quan-
tum due to the new capacity. It is the faét, that ice at 32°
cannot bear the fmalleft addition of heat in that ftate, but im-
mediately begins to be converted into water. Leta quantity
much lef{s than reprefented by 140°, enter a given portion of
ice, fay 4 a degree. A fmall portion of the ice becomes
water ; its capacity being increafed as 9:10, and here the
procefs flops; the entire mafs of ice and water remaining at
32°. More heat would alter the ftate and enlarge the capa--
city of more of the ice, without raifing its temperature ; that
is to fay, would fufe it. How this is done, or in other words,
what it is that happens among the particles may not be eafy
to explain or to imagine; but in my apprehenfion this hypo-
thetical part of the difcuffion would be at leaft as obfcure in the
do@rine of latent or combined heat, as in that which afcribes
the difappearance of heat during fufions to the enlargement of
capacity.
As to the difagreement of refults in the hands of different
philofaphers concerning the natural zero, it is to be obferved,
that it is one thing to determine whether bodies have different
capacities for heat, and: another to exprefs thefe by accurate
numbers. There can be no doubt of the fact that bodies have
different capacities, and Dr. Irvine’s theorem may enuntiate
itfelf generally, by faying, that as the capacity of the folid is
to
THEORIES OF HEAT. 929
to that of the fluid, fo is the whole heat of the folid to that of
the fluid. But it is a widely different thing to determine pre-
cifely the capacities of airs, and various other fubftances, ex-
, periments on which are fubje& to great inaccuracy, and muft
be carefully repeated many times before a philofopher fhould
pretend to draw final, and ftill lefs elementary, conclufions.
Many of the experiments by which contradiétory refults have
been obtained were made, (as I am told, for I have not yet
had an opportunity of examining mylelf) by the calorimeter,
an inftrument liable to great and deferved objeétions. Lavoifier,
by mixing fulphuric acid and water made the natural zero
5803: my father by a fimilar procefs fomewhere I think be-
tween 8 and 900. What will Dr. Thompfon make of this ?
Surely he will not conclude the theorem falfe, but one expe-
menter wrong ; moft likely both inaccurate.
It is very ftrange indeed that Dr. Thompfon fhould have Dr. Thompfon
found it dificult to underftand how thefe 140° enter ice during Fie
fufion without raifing its temperature. All he fays amounts of ice eae aly
to this, that a given quantity of heat will have more effect in changed ducing
; ; . theexperiment.
raifing the temperature of ice than that of water. But the ice
muft continue ice, and the water water, and a change of ca-
pacity alters the whole reafoning. Before he can tell whether
140 fhould be 14 or not, he muft tell me the whole heat of ice,
_and let me examine whether that be to itfelf plus, 140 as 9: 10
-ornot. He is exaétly in the fame error with regard to fteam. Deidisaees
As to a mode of finding the capacities of ice and water, Of method of afcer-
¢ which my father was the undoubted difcoverer, as well as of taining the capa-
the general faét that all bodies change their capacity and form LENO tn
together, one of Irvine’s modes was this: he mixed fine river afcertaining how
fand wafhed, or fine pounded glafs of a given temperature i oe
with each, fo as to raife or reduce each an equal number of equal change of
degrees, Then the capacities: were as the quantities of glafs pa ipa si
added to produce the fame effect.
Dr. Thompfon fays, that there is no proof that the capaci- aed ais
ties of bodies are as their abfolute heats. The capacity of iron, capacities are not
he continues, is greater than that of water or even that of azotic igs Piel as
gas, yet it is improbable that iron contains more heat than heats.
_ thefe fubftances. Now where did Dr. Thompfon find that Inftance of irons
.the capacity of iron was greater than that of water and azotic ee
gas? not in his own table furely. There iron by weight has and contain lets
capacity 0.1264, water 1,000, azotic gas, 0.7036, or as Dr. sete
Crawford miftakenly.
40 THEORIES OF HEAT.
Crawford fays, .7936. Even of equal bulks that of iron is
. lefs than that of water, as I fee in the fame table. I can only
fuppofe that Dr. Thompfon has ftumbled on the fpecific gravi-
ties inftead of {pecific heats, and there he would have been
right enough.
The fame expe- IT will fay only a few words farther on the queftion, whether
riment that de- ae : lags ; Ay aes
penance Tackle bodies contain caloric in proportion to their fpecific heats or
heats is alfo the not. Now firft of all when they continue of the fame capa-
ile oe cities. Suppofe the capacity of a body to be to that of water
abfoluteheats aS 10 to5,72.e. double. The fame quantity of heat that raifes
s (4 dete water two degrees, raifes it one; 2° more raife the body one
extende r
the whole range More, and fo on as far as we can go upwards, and the reverfe
from zero) = downwards in the fcale. But fuppofe another body whofe
taken to be in See je mae ;
the fame ratio. C@pacity is to that of water as 20 to 5, 7. e. quadruple. Each
4° of the heat in water raife this new body one degree up-
wards, and the reverfe downwards, as faras we know. Now
is it not probable here that the whole heats are in proportion
io the capacities thus determined, fince like thermometrical
portions of heat taken out of each and applied to water affeet
it in that ratio? The fpecific heats of bodies are faid to be
| different, when the fame quantity of heat raifes one a different
number of degrees from the other, and that regularly as far as
we can examine. ‘Therefore each degree in each contains a
quantity of heat proportional to its capacity, But the whole
heat is made up of degrees, therefore the whole heats are
proportional if the capacities remain the fame. Dr. Thomp-
fon grants this to be abfolute fa& to the extent of our experi-
ments. ;
If the capacities But if the capacity be fuppofed to vary, firft let it diminith.
Peel vey Then the quantity of heat given out is the difference of the
while the tempe= ;
raturechanges, Whole heats of the two different ftates of the body; and the
the only confe- whole-heat of it in each ftate is proportional to its capacity,
quence would be, : : ee
that beat would and the whole heat of its higheft capacity is equal to that of
be given out or its loweft plus the heat given out. Therefore the change of
abferbed ll 1 capacity has made no alteration on the whole heat of the body
common tempera- capacity has made no alteration on the whole heat of the body
ture werersftored; computed from a higher point, but will turn out the fame as
su peneoe if no change had taken place. ]
awould be propor- If the capacity be fuppofed to increafe, a fimilar reafoning
a. mW would fhew that the heat ftill may be computed in the fame
7 way. Such are a few arguments on the other fide of the quef-
tion
EXPERIMENTS ON ASTRINGENT VEGETABLES. Q1
tion from Dr. Thompfon, by no means all that might be
brought, nor dare I venture to hope fo ftated as to be beyond
the reach of cenfure.
Many more curious points rife before the imagination on fo Oacaae ee
interefting a fubjeét as heat. As I hope, however, foon tobe eaitnie at ae
able to lay before the public fome of my father’s writings, I late Dr. Irvine,
may on that occafion have an opportunity of exprefling my felf
at greater length than I can intrude in your journal.
lam,
SIR,
Your obedient humble fervant,
ghia WILLIAM IRVINE.
Bedford-Street, Covent-Garden.
awh
An Account of fome Experiments and Obfervations on the Confti-
tuent Parts of certain Aftringent Vegetables ; and on their Ope-
ration in Tanning. By Humepury Davy, Efq. Profe/~
for of Chemiftry in the Royal Inftitution.
- (Concluded from Page 256, Vol. V.)
LV. EXPERIMENTS AND OBSZRVATIONS ON THE AS-
TRINGENT INFUSIONS OF BARKS, AND OTHER VEGE-=
TABLE PRODUCTIONS.
Vue barks that I examined were furnifhed me by my friend Infufions of
‘Samuel Purkis, Efq. of Brentford; they had been colleéted in Parks in water
; y gentle heat.
the proper feafon, and preferved with care.
In making the infufions, I employed the barks in coarfe
powder ; and, to expedite the folution, aheat of from 100 to
120° Fahrenheit was applied.
The ftrongeft infufions of the barks of the oak, of the Lei- Of oak, willow,
cefter willow, and of the Spanifh chefnut, were nearly of the ven
fame {pecific gravity, 1.05. Their taftes were alike, and ftrong- ;
ly aftringeut; they all reddened litmus-paper ; the infufion of
the Spanifh chefnut bark producing the higheft tint ; and that
of the Leicefter willow bark the feebleft tint.
Two hundred grains of each of the infufions were fubmitted were chemical-
to evaporation; and, in this procefs, the infufion of the oak 'Y **#™ined-
bark
\
32
Chemical ex-
amination of
various barks.
EXPERIMENTS GN ASTRINGENT VEGETABLES.
bark furnifhed 17 grains of folid matter; that of the Leicefter
willow about 162 grains ; and that of the Spanifh chefnut nearly
an equal quantity.
The tannin given by thefe folid matters was, in that from the
oak bark infufion, 14 grains; in that from the willow bark in-
fufion 142 grains; and in that from the Spanifh chefnut bark
infufion 13 grains.
The refidual {ubftances of the infufions of the Spanifh chel-
nut bark, and of the oak bark, flightly reddened litmus-paper,
and precipitated the folutions of tin of a fawn colour, and thofe
of iron black. The refidual matter of the infufion of the wil-
low bark, did not perceptibly change the colour of litmus ; but
it precipitated the falts of iron of an olive colour, and render-
ed turbid the folution of nitrate of alumine.
The folid matters produced by the evaporation of the infu-
fions, gave, by incineration, only a very fmall quantity of
afhes, which could not have been more than ,2, of their ori-
ginal weights. Thefe afhes chiefly confifted of calcareous
earth and alkali; and the quantity was grealeft from the infu-
fion of chefnut bark.
The infufions were aéted on by the acids, and the pure alkalis,
ina manner very fimilar to the infufion of galls. With the fo-
lutions of carbonated alkalis, they gave denfe fawn-coloured
precipitates. They were copioufly precipitated by the folutions
of lime, of ftrontia, and of barytes; and, by lime-water. in
excefs, the infufions of oak and of chefnut bark feemed to be
deprived of the whole of the vegetable matter they held in -
folution.
By being boiled for fome time with alumine, lime, and mag-
nefia, they became almoft colourlefs, and loft their power, of ©
acting upon gelatine and the falts of iron. After being heated
with carbonate of lime and carbonate of magnefia, they, were
found deeper coloured than before; and, though they had loft
their power of aéting on gelatine, they ftill gave denfe olive-
. coloured precipitates with the falts of iron.
In all thefe cafes, the earths gained tints of brown, more or
le(s intenfe,
When the compound of the aftringent coinealead of the in-
fufion of oak bark with lime, procured by means of lime-water,
was acted on by fulphuric acid, a folution was obtained, which
pre-
EXPERIMENTS ON ASTRINGENT VEGETABLES. 33
precipitated gelatine, and contained a portion of the vegetable
principles, and a certain quantity of fulphate of lime; a folid
fawn-coloured matter was likewife formed, which appeared
to be fulphate of lime, united to alittle tannin and extraétive
matter. *
aa were copioufly precipitated by folution of al- aM
men.
The precipitates they gave with gelatine were fimilar in their
appearance ; their colour, at firft, was a light tinge of brown,
but they became very dark by expofure to the air. Their com-
pofition was very nearly fimilar; and, judging from the ex-
periments on the quantity of gelatine employed in forming them,
the compound of tannin and gelatine from the ftrongeft infufion
of oak bark, feems to confift, in the 100 parts, of 59 parts of
gelatine and 41 of tannin; that from the infufion of Leicefter
willow bark, of 57 parts of gelatine and 43 of tannin ; and that
from the infufion of Spanifh chefnut bark, of 61 parts of gela-
tine and 39 of tannin,
Two pieces of calf-fkin, which weighed when dry 120 grains Experiments of
each, were tanned ; one in the ftrongeft infufion of Leicefter ee re
willow bark, and the other in the ftrongeft infufion of oak bark. fions of barks.
The procefs was completed, in both inftances, in lefs than a ,
fortnight ; when the weight of the Jeather formed by the tannin
of the Leicefter willow bark was found equal to 161 grains;
and that of the leather formed by the infufion of oak bark was
equal to 164 grains.
When pieces of fkin were fuffered to remain in fmall quan- Spent ouze or
tities of the infufions of the oak bark, and of the Leicefter wil. infusion.
low bark, till they were exhaufted of their tanning principle,
it was found, that though the refidual liquors gave olive-colour-
ed precipitates with the folutions of fulphate of iron, yet they
were fcarcely rendered turbid by folutions of muriate of tin;
and there is every reafon to fuppofe, that a portion of their ex-
tra€tive matter had been taken up with the tannin by the fkin,
* M. Merat Guillot propofes a method of procuring pure tannin,
(Annales de Chimie, Tome XLi. p. 325.) which confifts in pre-
cipitating a folution of tan by lime-water, and decompofing it by
nitric or muriatic acid. The folution of the folid matter, obtained
in this way in alcohcl, he confiders as a folution of pure tannin;
but, from the experiments above-mentioned, itappears, that it muft
contain, befides tannin, fome of the extragtive matter of the bark;
and it may likewife contain faline matter.
Vou, VI.—SepremBer. D I at-
84 EXPERIMENTS ON ASTRINGENT VEGETABLES.
I attempted, in different modes, to obtain uncombined galli¢
acid from the folid matter produced by the evaporation of the
barks, but without fuccefs. When portions of this folid matter
were expofed to the degree of heat that is required for the pro-
duétion of gallic acid from Aleppo galls, no cry ftals were form-
ed; and the fluid that came over gave only a brown colour to
the folution of falts of iron, and was found to contain much
acetous acid and empyreumatic oil.
When pure water was made to aét, in fucceflive portions,
upon oak bark in coarfe powder, till all its foluble parts were
taken up, the quantities of liquor laft obtained, though they
did not act much upon folution of gelatine, or perceptibly red~
den litmus-paper, produced a denfe black with the folution of
fulphate of iron: by evaporation, they furnifhed a brown mat-
ter, of which a part was rendered infoluble in water by the
action of the atmnofphere; and the part foluble in water was
not in any degree taken up by fulphuric ether; fo that, if it
contained gallic acid, it was ina ftate of intimate union with
extractive matter.
low tanning Two pieces of calf-fkin, which weighed when dry 94 grains
sesh fun each, were flowly tanned 5 one by being expofed to a weak in-
of the leather fufion of the Leicefter willow bark, and the other by being acted
than quick, and ynon by a weak infufion of oak bark. The procefs was com-
more of the mu- : : ; :
cilage is taken Pleted inabout three months; and it was found, that one piece
De of {kin had gained in weight 14 grains, and the other piece
about 162 grains. This increafe is proportionally much lefs
: - than that which took place in the experiment on the procefs of
quick tanning. The colour of the pieces of leather was deeper
than that of the pieces which had been quickly tanned; and,
to judge from the properties of the refidual liquors, more of
the extraétive matters of the barks had been combined with
them.
The experiments of Mr. Biggin * have fhown, that fimilar
barks, when taken from trees at different feafons, differ as to
the quantities of tannin they contain: and I have obferved,
ihat the proportions of the aftringent principles in barks, vary
confiderably according as their age and fize are different ; be-
fides, thefe proportions are often influenced by accidental cir-
cumftances, fo that it is extremely difficult to afcertain their
diftin€ relations to each other.
*-Phil, Tranf. for 1799, page 299,
In
FXPERIMENTS ON ASTRINGENT VEGETABLES. 35
Tn every aftringent bark, the interior white bark (that is, the HR
part next to the ibarnten’ contains the largeft quantity of tan- mo tannin ;
nin. The proportion of extraétive matter is generally greateft the middle moft
s : ; ? extractive ; and
in the middle or coloured part: but the epidermis feldom fur- 44. épidermis
nifhes either tannin or extraétive matter. little of eithers
The white cortical layers are comparatively moft abundant in Young trees
young trees ; and hence their barks contain, in the fame weight, Be
a larger proportion of tannin than the barks of old trees. In
barks of the fame kind, but of different ages, which have been
cut at the fame feafon, the fimilar parts contain always very
nearly the fame quantities of aftringent principles; and the in-
terior layers afford about equal portions of tannin,
An ounce of the white cortical layers of old oak bark, fur- are quanti-
nifhed, by lixiviation and fubfequent evaporation, 108 grains of “*
folid matter ; and, of this, 72 grains were tannin. An equal
quantity of the white cortical layers of young oak produced 111
grains of folid matter, of which 77 were precipitated by gela-
tine,
An ounce of the interior part of the bark of the Spanith
chefnut, gave 89 grains of folid matter, containing 63 grains
of tannin.
The fame quantity of the fame part of the bark of the Lei-
eefter willow, produced 117 grains, of which 79 were tannin.
An ounce of the coloured or external cortical layers from the
oak, produced 43: grains of folid matter, of which 19 were
tannin.
From the Spanifh chefnut, 41 grains, of which 14 were
tannin.
And, from the Leicefter willow, 34 grains, of which 16 were
tannin.
In attempting to afcertain the relative quantities of tannin in
the different entire barks, I fele&ted thofe fpecimens which ap-
peared fimilar with regard to the proportions of the external
and internal layers, and which were about the average thick-
nefs of the barks commonly ufed in tanning, namely, half an
inch,
Of thefe barks, the oak produced, in the quantity of an
ounce, 61 grains of matter diffolved by water, of which 29
_ grains were tannin.
The Spanith chefnut 53 grains, of which 21 were tannin,
And the Leicetter willow 71 grains, of which 33 were tan-
nin.
D2 The
Properties of the
refijual portion
of infufed barks.
Elm and willow
bark,
infufions of
fumachs from
Sicily and Ma-
laga.
EXPERIMENTS ON ASTRINGENT VEGETABLES.
The proportions of thefe quantities, in refpeét to the tanning
principle, are not -very different from thofe eftimated in Mr.
Biggin’s table.*
The refidual fubftances obtained in the different experiments,
differed confiderably in their properties; but certain portions of
them were, in all inftances, rendered infoluble during the pro-
cefs of evaporation. The refiduum of the chefnut bark, as in
the inftance of the ftrongeft infufion, poffefled flightly acid
properties ; but more than 2 of its weight confifted of extrac-
tive matter. All the refiduums in folution, as in the other
cafes, were precipitated by muriate of tin; and, after this pre-
cipitation, the clear fluids a€ted much more feebly than before
on the falts of iron; fo that there is great reafon for believing,
that the power of aftringent infafions to precipitate the falts of _
iron black, or dark coloured, depends partly upon the agency
of the extractive matters they contain, as well as upon that of
the tanning principle and gallic acid.
In purfuing the experiments upon the different aftringent
infufions, I examined the infufions of the bark of the elm and
of the common willow. Thefe infufions were aéted on by re-
agents, in a manner exaétly fimilar to the infufions of the other
barks: they were precipitated by the acids, by folutions of the
alkaline earths, and of the carbonated alkalis; and they form-
ed, with the canftic alkalis, fluids not precipitable by gelatine.
An ounce of the bark of the elm, furnifhed 13 grains of
tannin,
The fame quantity of the bark of the common willow, gave
11 grains.
The refidual matter of the bark of the elm, contained a con-
fiderable portion of mucilage; and that of the bark of the
willow, a fmall quantity of bitter principle.
The ftrongeft infufions of the fumachs from Sicily and Ma-
laga, agree with the infufions of barks, in moft of their pro-
perties; but they differ from all the other aftringent infufions
that have been mentioned, in one refpect; they give denfe pre-
cipitates with the cauftic alkalis. Mr. Prouft has fhown, that fu-
mach contains abundance of fulphate of lime; and it is. pro-
bab!y to this fubftance that the peculiar effect is owing.
From an ounce of Sicilian fumach, I obtained 165 grains of
matter foluble in water, and, of this matter, 78 grains were
fannin,
* Philofophical Tranfaétions for 1799, p. 263. i
An
#XPERIMENTS ON ASTRINGENT VEGETABLES. 39
An ounce of Malaga fumach, produced 156 grains of folu-
ble matter, of ial 79 appeared to be tannin.
The infufion of Myrobalans * from the Eait Indies, differed Of Myrobalanse
from the other aftringent infufions chiefly by this circumftance,
thatiit effervefced vith the carbonated alkalis ; and it gave with
them a denfe precipitate, that was almoft immediately redif-
folved. After the tannin had been precipitated from it by ge-
latine, it ftrongly reddened litmus-paper, and gave a bright
black with the folutions of iron. I expeéted to be able to pro-
cure gallic acid, by diftillation from the Myrobalans; but in
this I was miftaken ; they furnifhed only a pale yellow fluid,
which gave merely a flight olive tinge to folution of fulphate
of iron.
Skin was fpeedily tanned in ihe infufion of the Myrobalans ;
and the appearance of the Jeather was fimilar to the appear-
ance of that from galls.
The ftrongeft infufions of the teas are very fimilar, in their
agencies upon chemical tefts, to the infufions of catechu.
An ounce of Souchong tea, produced 48 grains of tannin.
The fame quantity of green tea, gave 41 grains.
Dr. Maton has obferved, that very little tannin is found in
cinchona, or in the other barks fuppofed to be poffeffed of
febrifuge properties. My experiments tend to confirm the ob-
fervation. None of the infufions of the ftrongly bitter vegetable
fubftances that I have examined, give any precipitate to gela-
tine, And the infufions of quaffia, of gentian, of hops, and
of chamomile, are {carcely affe€ted by muriate of tin; fo that
they likewife contain very little extraétive matter.
In all fubftances poffefled of the aftringent tafte, there is
great reafon to fufpeét the prefence of tannin; it even exiftsin
fubftances which contain fugar and vegetable acids. I have
found it in abundance in the juice of floes; and my friend Mr,
Poole, of Stowey, has detedted it in port wine. |
V. GENERAL OBSERVATIONS,
Mr. Prouft has fuppofed, in his paper upon tannin and its Probability that
Species,+ that there exift different {pecies of the tanning prin- sy cries
ciple, poffeffed of different properties, and different pas tanning mattere
* The Myrobalans ufed in thefe experiments are the fruit of the
Terminalia Chebula. Retz. Obs. Botan. Fale, V. p. 31.
¢ Annales de Chimie, Tome XLI. p. 332. :
re
The fpecific
agencies of
tannin in all in=
fufions are
the fame.
Its affinities and
habitudes.
EXPERIMENTS ON ASTRINGENT VEGETABLES.
of aéting upon re-agents, but all precipitable by gelatine.
This opinion is fufficiently conformable to the faéts generally
known concerning the nature of the fubftances which are pro-
duced in organifed matter; but it cannot be confidered as
proved, till the tannin in different vegetables has been ex-
amined in its pure or infulated ftate. In all the vegetable
infufions which have been fubjeéted to experiment, it exits
in a ftate of union with other principles; and its properties muft
neceffarily be modified by the peculiar circumftances of its
combination,
From the experiments that have been detailed it appears,
that the /pecific agencies of tannin in all the different aftringent
infufions are the fame. In every inftance, it is capable of en-
tering into union with the acids, alkalis, and earths; and of
forming infoluble compounds with gelatine, and with fkin, The
infufions of the barks affeét the greater number of re-agentsina
manner fimilar to the infufion of galls; and, that this laft fluid
is rendered green by the carbonated alkalis, evidently depends
upon the large proportion of gallic acid it contains. The infu-
fion of fumach owes its charateriftic property, of being pre-
cipitated by the cauftic alkalis, to the prefence of fulphate of
lime; and, that the folutions of catechu do not copionfly pre-
cipilate the carbonated alkalis, appears to depend upon their
containing tannin in a peculiar ftate of union with extradlive
matter, and uncombined with gallic acid or earthy falts,
In making fome experiments upon the affinities of the tanning
principle, I found that allthe earths were capable of attraéting
it from the alkalis: and, fo great is their tendency to combine
with it, that, by means of them, the compound of tannin and
gelatine may be decompofed without much difficulty ; for,
after pure magnefia had been boiled for a few hours with
this fubftance diffufed through water, it became of a red-brown
colour, and the fluid obtained by filtration produced a diftin@
precipitate with folution of galls. The acids have lefs affinity
for tannin than for gelatine ; and, in cafes where compounds
of the acids and tannin are aGted on by folution of gelatine, an
equilibrium of affinity is eftablifhed, in confequence of which,
by far the greateft quantity of tannin is carried down in the in-
foluble combination. The different neutral falts have, com.
paratively, feeble powers of attraGtion for the tanning principle ;
but, that the precipitation they occafion in aftringent folutions,
is
~
EXPERIMENTS ON ASTRINGENT VEGETABLES. 89
is not fimply owing to the circumftance of their uniting to a
portion of the water which held the vegetable fubftances in fo-
lution, is evident from many faéts, befides thofe which have
een already ftated. The folutions of alum, and of fome
other falis which are lefs foluble in water than tannin, pro-
duce, in many aftringent infufions, precipitates as copious as
the more foluble faline matters ; and fulphate of lime, and other
earthy neutral compounds, whichare, comparatively fpeaking,
infoluble in water, {peedily deprive them of their tanning
principle.
From the different faéts that have been ftated, it is evident It is not always
that tannin may exift in a ftate of combination in different fub- pl as ey
ftances, in which its prefence cannot be made evident by
means of folution of gelatine; and, in this cafe, to deteé its
exiftence, it is neceflary to have recourfe to the a¢tion of the
diluted acids.
In confidering the relations of the different faéts that have Skins in tanning
been detailed, to the proceffes of tanning and of leather-making, ae ae
it will appear fufficiently evident, that when {kin is tanned in
aftringent infufions that contain, as well as tannin, extractive
matters, portions of thefe matters enter, with the tannin, into
chemical combination with the fkin. In no cafe is there any
reafon to believe that gallic acid is abforbed in this procefs 5
and M. Seguin’s ingenious theory of the agency of this fub-
ftance, in producing the deoxigenation of {kin, feems fup-
ported by no proofs. Even in the formation of glue from
fkin, there is no evidence which ought to induce us to fuppofe
that it lofes a portion of oxigen; and the effect appears to be
owing merely to the feparation of the gelatine, from the fall
quantity of albumen with which il was combined in the orgae
nifed form, by the folvent powers of water.
The different qualities of leather made with the fame kind os bee ale
of fkin, feem to depend very much upon the different quantities affedied by it :
of extractive matter it contains. The leather obtained by means
of infufion of galls, is generally found harder, and more liable
to crack, than the leather obtained from the infufions of barks ;
and, in all cafes, it contains a much larger proportion of tannin,
and a fmaller proportion of extraétive matter. |
When fkin is very flowly tanned in weak folutions of the Soft durable
barks, or of catechu, it combines with a confiderable proportion ae flow
of extractive matter; and, in thefe cafes, though the increafe
of
r@) EXPERIMENTS ON ASTRINGENT VEGETABLES.
of weight of the {kin is comparatively fmall, yet it is rendered
perfectly infoluble in water ; and is found foft, and at the fame
time ftrong.
The fatarated aftringent infufions of barks contain much lefs
extra€tive matter, in proportion to their tannin, than the weak
infufions ; and; when {kin is quickly tanned in them, common
experience fhows that it produces leather lefs durable than the
leather flowly formed.
The common Befides, in the cafe of quick tanning by means of infufions
opinion in favour of barks, a quantity of vegetable extraétive matter is loft to the
of what is called * : : f
feeding of the Manufacturer, which might have been made to enter into the
leather probably compofition of his leather. Thefe obfervations fhow, that there
ant. is fome foundation for the vulgar opinion of workmen, con-
cerning what is technically called the feeding of leather in the
flow method of tanning ; and, though the proceffes of the art
may in fome cafes be protraéted for an unneceffary length of
time, yet, in general, they appear to have arrived, in con-
fequence of repeated praétical experiments, at a degree of
perfection which cannot be very far extended by means of any
elucidations of theory that have as yet been made known.
On the firft view it appears fingular that, in thofe cafes of
tanning where extra@live matter forms a certain portion of the
leather, the increafe of weight is lefs than when the {kin is
combined with pure tannin ; but the faét is eafily accounted for,
when we confider that the attraGtion of {kin for tannin muft be
probably weakened by its union with extraétive matter; and,
whether we fuppofe that the tannin and extraétive matter enter
together into combination with the matter of fkin, or unite with
feparate portions of it, flill, in either cafe, the primary attraGion
of tannin for {kin muft be, toacertain extent, diminifhed
Vegetables are In examining aftringent vegetables in relation to their powers
Se A of tanning {kin, it is neceflary to take into account, not only
by the matter the quantity they contain of the /ubfance precipitable by gela-
that glue can tine, but likewife the quantity, and the nature, of the extraétive
a aie matter; and, in cafes of comparifon, it is effential to employ
infufions of the fame degree of concentration.
Catechu is the It is evident, from the experiments detailed in the IIId fec-
mot powerful tion, that of all the aftringent fubftances which have been as
fanning material. ; : ; :
yet examined, catechu is that which contains the largeft pro-
portion of tainin; and, in fuppofing, according to the common
eflimation, that from four to five pounds of common oak bark
are
METHOD OF RAISING WATER. A]
are required to produce one pound of leather, it appears, from
the various fynthetical experiments, thai about half a pound of
catechu would anfwer the fame purpofe *.
Alfo, allowing for the difference in the compofition of the Its comparative
different kinds of leather, it appears, from the geneval detail of sa cae
faéts, that one pound of catechu, for the common ufes of the
tanner, would be nearly equal in value to 24 pounds of ies
to 7; pounds of the bark of the Leicefter villi to 11 pounds
of thie bark of the Spanifh’ chefnut, to 18 pounds of the bark of
the elm, to 21 pounds of the bark of the common willow, and
to 3 pounds of fumach. .
Various men{truums have been propofed for the purpofe oe and other
expediting and improving the procefs of tanning, and, amongft robs tines
them, lime-water and the folutions of pearl-afh: but, as thefe ful.
two tubftances form compounds with tannin which are not de-
compofable by gelatine, it follows that their effects muft be
highly pernicious; and there is very little reafon to fuppofe,
that any bodies wili be found which, at the fame time that they
increafe the folubility of tannin in water, will not likewile di-
minifh its attra€tion for {kin.
VI.
An eafy Method of raifing Water for the Purpofes of Refrigeration
én Dijirlleries, Steam Condenjers, &c. By Sir A. N. Epe-
CRANTZ. Communicated by the Inventor.
"Tue method exhibited in the fketch, Fig. II. Plate IV. Introductions
being capable of faving near thirty feet of the height to which
water may be required to be pumped, for the ufes mentioned
in the title, appeared too fimple and ingenious, when the learn-
ed inventor did me the honour to mention it in converlfation,
for me not to require permiffion 1o communicate it to my
readers.
* This eftimation agrees very well with the experiments lately
made by Mr. Purkis, upon the tanning powers of Bombay catechu
in the proceffes of manufacture, and which he has permitted me to
mention. Mr. Purkis found, by the refults of different accurate
experiments, that one pound of catechu was equivalent to feven or
eight of oak bark.
3 If
42 METHOD OF RAISING WATER.
The principle of If the worm tube were open at the top as ufual, itis evident
aero pe that all the water employed for cooling, would require to be
acurrentof _raifed by fome mechanic force as high as the furface ; fuppofe
mi os 4 twenty feet. But as this water is not wanted for ufe at that
elevation, but is only required to give out its heat, and then
fall down again; it is clear that this fall may be applied to
raife a confiderable portion of what is’to follow. Various
means might be devifed for fuch an application ; the fimpleft
and moft effeétual, no doubt, is that to which Sir A. N. has
given the preference, namely to convert the whole apparatus
into a fyphon.
Defcription of Suppofe the worm tub to be clofed at top; the cold water
the apparatuss conveyed into it at the bottom from the veffel A, and carried off
heated at top by the pipe B into the overflowing veffel C.
Let us fuppofe the level in A to be two feet higher than that
in C, and acurrent will be kept up through the whole fluid as
long as may be defired.
Whether the It muft occur to the experienced engineer that gas or air
ea ett or Willefcape from the water, efpecially when heated and defended
impede the from the preflure of the atmofphere. But this may be obviated
eis by attending to a few neceflary circumftances. Firft, the
elevation need not be very great, and lefs gas will efcape ;
fecondly, the temperature may be kept down by a large
current through pipes of confiderable diameter; and thirdly,
jt is praéticable by various contrivances, that an interior float
fhall give notice when the gas has lowered the furface of the _
water beneath it to a ceriain point, and this may either warn
an attendant to pump it out, or it may difcharge an apparatus
to produce the fame effect without the immediate exertion of
labour each individual time.
Concerning thefe and other fecondary points, I fhall not,
however, enlarge ; having enough to regret from the neceflary
imperfection of this defcription, taken from the converfation
of the inventor, inftead of being given in his own words.
W. N.
Deferipiion
2
DESCRIPTION OF A NEW PADLOCK. 43
VII.
Defcription of a new Padlock of Security with Combinations. By
Citizen ReGnier.*
Tue intention of this padlock is to fecure portmanteaus, cloak Defeription of a
7 padlock of com-=
bags, and other packages in the moft complete manner, and to}; , ation,
ferve occafionally as defences to the key-holes of the doors of
apartments.
The padlock is compofed of four circular pieces of brafs,
on which are engraven the twenty-four letters of the alphabet.
The four pieces are moveable on their axes by turning them
with the finger in order to produce the combination by which
it is opened.
The combination of the manufaéturer is the word ROME ;
when this word is brought intoa correé line with the two marks
on the edges of the two fteel plates FF, which form the ex-
ternal part of the padlock, thofe two plates can be feparated
alittle from each other, and the clafp of the lock can be opened
by the hinge.
The fame procefs is ufed to faften it, with this difference,
that the two external plates are prefled together fo as to con-
fine the bow or clafp of the lock in its cell at G ; after which,
the combination is to be thifted fo that the chara¢ters fhall no
longer form the fame word in the before-mentioned line.
The Method by which the Poffeffor may difpofe the Padlock to a&
by a new Combination, which cannot be known to any other
Perjon:
1. A fcrew is taken out, which pafles through the centre of
the plates FF.
2. The combination which it is intended to fet afide, namely,
that which opens the lock at prefent muft be duly arranged.
3. The marked circular pieces or rings muit be taken off
from four plates of brafs which conftitute the central part,
and together form the centre-piece of the mechanifm.
4, Laftly, The rings muft be replaced on the centre pieces,
each according to the letter the poffeffor may have chofen.
For example: If you would adopt the word LOCK for the
combination, the letter L of the firft ring muft be placed over
* Tranflated from a paper circulated by the conitructor.
, or
Aid
Defcription of a
padlock of com-
hinatione
DESCRIPTION OF A NEW PADLOCK,
or upon a fall fteel tooth, which is attached to the firft interior
cylinder; the letter O of the fecond ring on the tooth of the
fecond cylinder; the letter C of the third ring on the tooth of
the third cylinder; and laftly, the letter K of the fourth tooth
on the fourth cylinder.
By this means the word lock is fet up and becomes the come
bination of the lock, and the word Rome no longer produces
the difpofition of parts required for the difengagement.
After this operation the fcrew mutt be replaced in the centre
of the plate; this {crew does not contribute to the ftrength of
the mechanifm ; but is ufed merely to allow the exaét {pace
neceflary for opening the padlock, and to prevent the fepara-
tivn of the rings from the central parts in the common ufe of
the lock.
Method of ufing this Lock as a Defence to the Key-hole of a Door.
A ring ftaple A, having a wood {crew, is fixed to the door
above ihe key-hole or efcutcheon of the lock.
A fecond ring C is fixed perpendicularly beneath the other,
A cylindrical tube of iron D, in the form of a bolt, is placed
vertically in the ring of thefe ferew ftaples. At the lower
end of the tube is an aperture, through which the padlock is
inferted, fo that the tube or bolt cannot be raifed or taken
out.
By this contrivance the key-hole of the lock is completely
defended, and the introduétion of a pick-lock or falfe key is ~
‘rendered morally impoffible. For the mechanifm prefents
331,776 combinations, * forming 331,775 different obftacles,
to prevent the removal of this defence by any perfon unac-
quainted with the fecret of the proprietor.
If it be apprehended that the word of the combination may
be forgotten, it will be eafy to write and difguife it in many
different ways, without any rifk of difcovery: for example,
The letter L, or eleventh letter of the alphabet oe
will be written 1.
The letter O, or fourteenth letter - é us So,
The letter C, or third letter - ~ re 2 bal Be
The letter K, or tenth letter = 7 - - 10,
Total (expreffed) £. 38.
* Number equal to the 4th power of 24, ;
This
_ DESCRIPTION OF A NEW PADLOCK. AD
. This little calculation will appear to any other perfon to be Defcription of a,
acommon account, but it is to the proprietor a memorandum pasion es tes
by which he will perfeétly recolleét that the firft letter of his
combination is the eleventh of the alphabet, that the fecond
is the fourteenth, and fo of the reft.
REMARKS.
This padlock appears at firft fight fimilar to that contrived
by Cardan; but we know that his was not capable of having
its combinations changed; whence it refults that the manufac-
turer, the retailer, and every other perfon who may have feen
it opened, can themfelves open it with the fame facility as the
proprietor himfelf. The notches which produce the opening
may be alfo difcovered by the feel; our lock has falfe notches
cut in the centre-piece of the mechanifm which prevent the dif-
covery of the real one.
Laftly, The clafp of this padlock is made of hardened and
tempered fteel, to prevent its being eafily cut by an ordinary
file. It is annealed fo far only as to prevent its breaking.
' ; AnnoraTion. -W.N.
The remaining part of this paper contains the addrefs of the
inventor and vendor, C. Regnier, ci devant Jacobins, Rue Do-
minmique, F. St. Germain a Paris, and alfo a certificate of ho-
nourable mention, &c. from the Athenée des Arts.
- The lock of Cardan confifts of the four vifible circular parts
carrying the alphabet. Thefe as well as the central parts of
the prefent lock are perforated half way through their centers
by an hole, and quite through by a fmaller hole, in the fide of
which laft there 1s a notch extended to the circumference of
the larger hole. All the four pieces are placed upona central
pin, which has fide projections anfwering refpedtively to the
notches, but occupying the fpace of the larger hole while the
lock is clofed. From this conftruéction it is evident that the
lock cannot be opened unlefs every one of the notches be placed
oppofite its projeGtion; that this pofition or placing is fettled
by the maker, and not variable; and that the lock is liable to be
opened, though not eafily, by the tentative procefs defcribed
at p. 204 of our laft volume.
Cit. Regnier has perfeéted the lock of Cardan by seis
the fyftem of the alphabet moveable with regard to the inter-
nal
46
Defeription of a
padlock of com-
bination.
Former paper
of the author,
and of Monge,
upon horizontal
refraction.
QUANTITY OF HORIZONTAL REFRACTION.
nal notch at the pleafure of the poffeffor, and alfo by making
groves or fmall notches on the face of each central piece,
which anfwer the purpofe of the teeth recommended at the
page laft quoted, by preventing the rings from being turned
round while any pull is made againft the clofure.
I find fome obfcurity in his defcription of the manner of
connecting the central piece and the external engraved part.
From the operation, I apprehend, 1. that each ring has a
number of notches at its inner furface, that anfwer to the letters
on its outer face; 2. that each central round piece fits the
cavity of its ring, and is prevented from turning by a tooth
which it lodges in one of the notches; 3. that when all the
four teeth are ranged in a line between F and F, the lock will
open; and therefore, 4, when any particular letter is placed
over the tooth, that letter becomes the effeétive letter for its
own ring. |
VIII.
Obfercations on the Quantity of horizontal Refraction; with a
Method of meafuring the Dip at Sea. By Witttam Hype
Wo utaston, M.D. F.R.S.*
In a Paper which I fome time fince prefented to this Society,
(printed in the Phil. Tranf. for 1800,) I endeavoured to afcer-
tain the caufes, and to explain the various cafes, of horizontal
refraction, which I had either obferved myfelf, or had feen
defcribed by others.
At the time of writing that effay, I had not met with the
Mémoires fur PEgypte, publifhed but a fhort time before; and
I was not aware that an account had been given by M. Monge,
of the phenomenon known to the French by the name of
mirage, which their army had daily opportunities of feeing, in
ibeir march through the deferts of Egypt.
In the perufal of this memoir, I could not fail to derive
inftruétion from the information it contained; but, as the faéts
related by him accord entirely with the theory that I had
advanced, I was by no means induced to adopt the explana-
tion that he has.propofed, in preference to my own.
* From the Philofophical Tranfations for 1803.
3 The
“QUANTITY OF HORIZONTAL REFRACTION,
47
The definite refleG@ing furface which he fuppofes to take Objection to ths:
place between two ftrata of air of different denfity, is by no
means confiftent with that continued afcent of rarefied air
which he himfelf admits ; and the explanation founded on this
hypothefis will not apply to other cafes, which may all be
fatisfaGtorily accounted for, upon the fuppofition of a gradual
change of denfity, and fucceffive curvature of the rays of light
by refraétion.
‘I have fince learned that the fame fubjeét has alfo been ably
theory of Monges
The fubjeé& well
treated by Wolte
treated by Mr. Woltman, in Gilbert’s Aanalen der Phyfik “ae
but I have to regret that his differtation, as well as that of
Gruber, in the fame Annals, were written in a language that
was unknown to me, and that I could not avail myfelf of the
afliftance that I might otherwife have received from their
refearches.
When I formerly engaged in this inquiry, being imprefled
with the advantage to be derived from it to nautical aftronomy,
on account of the variations in the dip of the apparent horizon,
from which all obfervations of altitude at fea muft neceflarily
be taken, I fuggefted the expediency of a feries of obfervations,
to be made by a perfon attentive to thofe changes of tempera-
ture or moifture of the atmofphere, on which he might find the
depreffion of his horizon principally to depend. I had at that
time no expeétation that I could myfelf purfue this fubjeét
farther to any ufeful purpofe, having little profpeét of refiding
for a fufficient length of time in view of the fea, and feeing no
other method by which the fame end might be accomplithed.
I have, however, fince that time, found means to fatisfy myfelf,
_ by obfervations over the furface of the Thames, that although
Obfervations
over the furface
of the Thames:
the quantity of refraétion varies in general with any change of »
the thermometer or hygrometer, yet the law of thefe variations
is not altogether fo fimple as I had hoped it might be found.
I hall, on the prefent occafion, firft relate the faéts on which
this opinion is founded, and which are in themfelves fufficiently
remarkable, on account of the unexpected quantity of refraction
obfervable over a fhort extent of water; I fhall, in the next
place, fhew that the exact determination of the concurrent
changes of the atmofphere are of lefs value, and their irregu-
larities of lefs confequence, than I had conceived, as there isa
very eafy method whereby the quantity of dip at fea may be at
any time correctly meafured ; and therefore the end which I
fought by indireét means, may be at ence direétly attained.
The
Narrative.
48 QUANTITY OF HORIZONTAL REFRACTION.
Apparent diftor- ‘The firft inflance that occurred to me, of obfervable refrac
pais ales tion over the furface of the Thames, was wholly accidental.
over the furfice [ was fitting in a boat near Chelfea, in fuch a pofition that
of the Thames. my eye was elevated about half a yard from the furface of the
water, and had a view over its furface, that probably forne-
what exceeded a mile in length, when I remarked that the
oars of feveral barges at a diftance, that were then coming
up with the tide, appeared bent in various degrees, according
‘to their diftance from me. The moft diftant appeared nearly
in the form reprefented, Plate I. Fig. 1. dd being my vifible
horizon by apparent curvature of the water; ab the oar itfelf
in its inclined pofition ; and bc an inverted image of the por-
tion be. By a little attention to other boats, and to buildings
on fhore, I could difeern that the appearance of all diftant
objeéts feen near the furface of the water was affeéted in a
fimilar manner, but that fearcely any of them afforded images
fo perfe€ily diftin@ as the oblique line of an oar dipped in the
water.
Thefe effects A perfon prefent at the time (as well as fome others to
are diffe «nt whom I have fince related the circumftance) was inclined to
froin what : ae :
might be caufed attribute the appearance ‘to refleétion from the furface of the
by geficction, water; but, by a moderate fhare of attention, a very evident
difference may be difcovered between the inverfion occafioned
by refie@lion, and that which is caufed by atmofpherical refrac-
tion. In cafes of refle€tion, the angles between the objeét and
image are fharp, the Jine’ of contaét between them ftraight and
well defined, but the lower part of the image indefinite and
confufed, by means of any flight undulation of the water. But,
when the images are caufed-by refraétion, the confines of the
objeét and its inverted image are rounded and indiftin@, and
the lower edge of the image is terminated by a ftraight line at
the furface of the water. In addition to thefe marks of diffe-
rence, there is another circumftance which, if attended to,
muft at once remove all doubt ; for, by bringing the line of
fight near to the furface of the water, boats and other {mall
objects are found to be completely hidden by an apparent hori-
zon, which, in fo fhort a diftance, cannot be owing to any
real curvature of the water, and can arife folely from the bend-
ing of the rays by refraétion.
They appear When I refleéted upon the caufes which were probably in-
referrible to an ftrumental in the production of thefe phenomena, they appeared
higher temperae :
thie in the . referrible
QUANTITY OF HORIZONTAL REFRACTION, 49
referrible to difference of temperature alone. After a fuccef- water, which —
fion of weather fo hot that the thermometer, during one month “ane Snnnim iat
preceding, had been 12 times above 80°, and on an average of ee et of
the month at 68°, the evening of that day (Auguft 22, 1800) rane
was unufually cold, the thermometer being 55°. The water power.
might be fuppofed to retain the temperature it had acquired
during afew weeks preceding, and, by warming the ftratum of
air immediately contiguous to it, might caufe a diminution of
its refractive denfity, fufficient to effeét this inverted curvature
of the rays of light, in the manner formerly explained. As L
was at that time unprovided with inftruments of any kind, I
had it not in my power to eftimate the quantity of refraétion, or
temperatures ; and can only fay that, to my hand, the water
felt in an uncommon degree warmer than the air.
Being thus furnifhed with an unexpeéted field for obferva- Particular ace
tion, I from that time took fuch opportunities as fimilar changes 6°Mt of the
; ks : obfervations.
of the weather afforded me, of examining and meafuring the
quantities of refraction that might be difcovered by the fame
means over another part of the river, that I found moft fuited
to my convenience.
The fituation from which the greater part of my obfervations
were made, was at the S. E. corner of Somerfet houfe. The.
view from this {pot extends under Blackfriars bridge, towards
London bridge, upwards of a mile in length, and in the oppo-
fite direétion through Weftminfter bridge, which is three
quarters of a mile diftant.
Such diftances are however by no means neceflary ; and in«
deed the air over the river, in cold weather, is generally, or
at leaft very frequently, not fufficiently clear for feeing diftin€lly
to fo great diftances. For, fince the winds which are moft
likely to effeét a fufficient change of temperature, on account
of their coldnefs, are ufually from the E. or N. E. the principal
f{moke of the town is then brought in that direétion, and hovers,
like a denfe fog over the courfe of the river, This circum=
ftance deprived me of many opportunities which the changes
of the thermometer indicated to be favourable for my purpofe,
and obliged me often to make ufeof fhorter diftances than I
fhould otherwife have chofen, by bringing the line of fight as
near as I could to the furface of the water.
For this purpofe, I had a plane reflector fitted to the obje@-
end of a fmall pocket telefcope, at an angle of 45°, fo that,
Vou. VI.—SEPTEMBER. E when
QUANTITY OF HORIZONTAL REFRACTION.
when the telefcope was held vertically, it gave a horizontal
view at any level that was found moft eligible. When the
water has been calm, I have obferved that the greateft refrac-
tion was vifible within an inch or two of its furface, and I have -
then feen a refraétion of fix or feven minutes in the fpace of
300 or 400 yards: at other times, I have found it greateft at
the height of a foot or two; but, in this cafe, a far more ex-
tenfive view becomes neceflary.
The firft meafures that I took were on the 23d of September,
1800. The water was 24° warmer than the air, and I found
a refraction of about 4%,
Od. 17. The difference of temperature was 3°, and the
refraction 3’.
Oct. 22. The water was 1]2° warmer than the air, yet the
quantity of refraétion did not exceed 3’.
The fmallnefs of the quantity of refra€tion upon this occa-
fion, I attributed to the drynefs of the atmofphere, conjeCturing
that a rapid evaporation might in great. meafure counteract
that warmth which the water would otherwife have commu-~
nicated to the air,
. From that time, therefore, I have noted not only the heights
of the thermometer in the water and in the air, but have added.
alfo the degrees of cold produced by keeping the bulb of it
moiftened for a fufficient time to render it ftationary. In con-
firmation of my conjeéture refpegting the drynefs of O&. 22,
I have alfo, in the following Table, which comprifes the whole _
of my obfervations, inferted a column from the Regifter kept
at the apartments of the Royal Society, containing the heights
of the hygrometer, on thofe mornings when my obfervations
were made, ‘
TABLE,
QUANTITY OF HORIZONTAL REFRACTION. | BL
TABLE.
At 8, A.M. | a... | rater, | Diffe- | Refrac-] Cold by | Hygro- Table of obfere
rence. tion. {evaporation.} meter. vations:
errr | | | rrr |
1800. Sept. 23} 57 | 603° | 32° | 4 zoe 79°
O&. 17} 463] 494 3 3 —— 72
221 38 | 49% | 112 | 3 -— 67
Nov. 1} 41 | 454 44 | 8 2 la
4| 432) 462 3 3- 12 72
5| 37 | 45 8 8 + 1 69
12] 442} 482 4 1+ 32 73
13] 40 | 444 4 15 2 76
1801. June 13] 50 | 63 13 9 + 5 65
221 55 | 61 6 6 +. 6 65
BUSS G2 7 6 42 65
24, 55 | 61 6 3 3 67
Sept. 8] 60 | 64 4 7 2 78
9) 64 | 642 2 5 3 7 A
10}; 58 | 64 6 7 Z 70
12 o’clock, 10] 63 | 64 1 2
From a review of the preceding Table it will be found, upon The dip of the
the whole, that when the water is warmer than the air, fome Mirren aia
increafe of depreflion of the horizon may be expected ; but by the water
ont its quantity will be greatly influenced, and in general Sting Warmer
diminifhed, by drynefs of the atmofphere. UPd ainsinimiea
It appears, however, that no obfervable regularity is dedu<(more confider-
cible from the meafures above given; but that the quantity, shi ihor ate
on fome occafions, is far different from what the ftates of the The meafares
thermometer and hygrometer would indicate. On the 9th of indicate little of
siden ‘ ’ any practical
September, for inftance, the difference of temperature is only jay,
2°, and the evaporation, to counteraét this flight excefs of
warmth, produced as much as 3° of cold; neverthelefs, the
refra€tion vifible was full 5’. In this obfervation T think that
EI could not be miftaken, as the water was at the time perfectly
calm, the air uncommonly clear, and I had leifure to pay par-
ticular attention to fo unforefeen an occurrence.
This one inftance appears conformable to the opinion enter- Solution of
tained by Mr. Huddart, and by M. Monge, that, under fome ™oifture not of
; f ; much probable
-eircumftances, the folution of water in the atmofphere caufes a conicquencée
decreafe in its refra€tive power; but, on no other occafion
have I been induced to draw a fimilar inference,
E 2 The
It is not likely
that fo great a
variation of the
dip happens out
at fea.
Mr. Huddart’s
remedy.
QUANTITY OF HORIZONTAL REFRACTION.
The objeét that I have at all times chofen, as fhewing beft
the quantity of refraétion, has been either an oar dipped in the
water at the greateft difcernible diftance, or fome other line
equally inclined; and the angle meafured has been, from the
point where the inverted image is terminated by the water, to
that part of the oar itfelf which appears to be direétly above it.
(The apparent magnitude of ec, Fig. 1. Pl. 3.)
The eight firft angles were taken with a mother-of-pearl
micrometer in the principal focus of my telefcope, and are not
fo much to be depended upon for accuracy as the fucceeding
eight. Thefe laft were meafured with a divided eye-glafs
micrometer, and confequently are not liable to any error from
unfteadinefs of the inftrament or objeé.
From the foregoing obfervations we learn, that the quantity
of refraétion over the furface of water may be very confiderable,
where the land is near enough to influence the temperature of
the air. At fea, however, fo great differences of temperature
cannot be expected; and the increafe of dip caufed by this
variation of horizontal refra€tion, it is to be prefumed, is not fo
great as in the confined courfe of a river; but, if we confider
that it may alfo be fubjeét to an equal diminution from an op-
pofite caufe, and that the horizon may even become apparently
elevated, there can be no queftion that the error in nautical
obfervations, arifing from a fuppofition that it is invariably
according to the height of the obferver, ftands in need of
correction.
The remedy employed by Mr. Huddart,* of taking two
angles of the fun from oppofite points of the horizon at the
fame time, and confidering the excefs of their fum above 180°
as double the dip, muft without doubt be effe€tual ; but, from
caufes which he affigns, it is pra€ticable only within certain
limits of zenith diftance; for, where the zenith diftance is
fmall, and the changes of azimuth rapid, there is required con-
fiderable dexterity and fteadinefs of a fingle obferver who at-
tempts to turn in due time, from one obfervation to another ;
and, when it exceeds 30°. the greater angle cannot be mea-
fured with a fextant, and confequently his method is, with
that inftrument, of ufe only in low latitudes.
, * Phil. Tranf. for 1797, p. 40.
On
QUANTITY OF HORIZONTAL REFRACTION. 53
On account of the difficulty attending fome of the adjuft- Objeétions to
ments for the back obfervation, he rejeéts that method © Gata rleys/7
taking angles in general, with much reafon; but he has thereby ae
overlooked a means of determining the dip, which I am inclined
to think might be employed with advantage in all latitudes, _
without any occafion to hurry the moft inexperienced or cau-
tious obferver.
By the back obfervation, the whole vertical angle between but the method
any two oppofite points of the horizon may be meafured at ee eae
once, either before or after taking an altitude. Half the ex-arc between the
cefs of this angle above 180°, fhould of courfe be the dip re- eg hori-
quired.
But, if it be doubtful whether the inftrument is duly adjufted, Error of the
a fecond obfervation becomes neceflary. The inftrument mutt a ae
be reverfed, and, if the apparent deficiency of the oppofite whole sate
angle from 180° be not equal to the excefs before obtained, ™°"'s
the index error may then be correéted accordingly; and, fince
the want of adjnftment, either of the glaffes at right angles to
the plane of the inftrument, or of the line of fight parallel to it,
will affeét both the larger and fmaller angle very nearly in an
equal degree, the } part of their difference will be extremely
near the truth, and the errors arifing from want of thofe ad-
juftments may with fafety be neglected.
This method of correéting the index error for the back obfer- as firft fuggefted
vation at fea, was many years fince recommended by Mr, by Ludlame
Ludlam ; * yet I do not find that it has been noticed by fubfe- ;
quent writers on that fubjeét, or fuggefted by any one for
determining the dip; but I can difcover no reafon for which it
could be rejeGted as fallacious, and I fhould hope that in prac-
tice it would be found convenient, fince in theory it appears to
be effeétual.
The moft obvious objection to this, as well as to Mr. Hud- Whether refrac-
dart’s method, is the poffibility that the refra@tion may be in Pai pose.
fome meafure different in oppofite points of the horizon at the ferent bearings
fame time. When land is at no great diftance, fuch an in- 2 the fame
equality may be found to occur; but, upon the furface of the ee
ocean in general, any partial variations of temperature can
rarely be fuppofed to exift ; and it is probable, that under any
circumflances, the difference will not bear any confiderable
* DireStions for the ufe of Hadley’s quadrant, 1771, § 82, p. 56.
proportion
54
Uncommon
halos round the
fune
ACCOUNT OF TWO HALOS.
proportion to the whole refraétion ; nor can it be thought a
fufficient reafon for rejecting one correétion propofed, that
there may yet remain other {mall errors, to which all methods
are equally liable, but which it is not the objeét of the prefent
differtation to rectify.
IX.
An Account of Two Halos, with Parhelia. By Sir H.C.
ENGLEFIELD, Bart. F. R. S*.
On the 20th of November, 1802, at two o’clock in the
afternoon, going out of doors, at Richmond in Surry, I per~
ceived the fun, accompanied by uncommon halos and parhelia,
The weather was fhowery, and the fky had that peculiar
turbid appearance, which is the certain forerunner of heavy
and Jong continued rain. The fun fhone with a faint and
watery light, was very ill defined, and appeared rather elon-
gated in a vertical direétion. A very denfe cloud occupied
all that quarter of the horizon, and rofe up pretty near to the
fun. Very heavy clouds covered the eaftern part of the
heavens, extending quite to the north, and were proceeding
gradually towards the fouth weft. The wind was about eaft.
The altitude of the fun was 14°. The circle neareft the
fun was diftant from him nearly 24°, and was about a de-
gree in breadth, It was of a pale yellowifh light, but had
no tendency to prifmatic colours.
On ihe left hand, it extended below a line drawn through
the fun parallel to the horizon. To the right, it terminated
in denfe clouds confiderably above that line.
The exterior circle was 48° from the fun, and it might be
14° in breadth, as it was evidently broader than the inner
circle. It terminated on either hand at nearly the fame
height as the interior one. It was tinged throughout with
- the prifmatic colours, though only red, green, and blue, were
diftinétly vifible. The red was neareft the fun, The blue
very faint. ‘The brightnefs of this circle was about that of the
fecondary rainbow, to abright common bow.
* Royal Inftitution, II. 1. i
a
ACCOUNT OF TWO HALOS, 55
In a line parallel to the horizon, paffing through the fun, Uncommon
there was, in the left hand branch of the inner circle, a very ¢* ai borage
faint parhelion ; but in the upper point of the fame circle,
there was a very bright and remarkable one. Its light was fo
vivid, that it could fearcely be fteadily viewed ; and, indeed,
it was rather brighter than the real fun. It was of a whiter
light than the reft of the circle in which it was, and had a
pearly appearance, as partaking a little of prifmatic tints. It
was large, perhaps in its brighteft part near two degrees broad,
very ill defined every where, but moft diffufed in the part
furtheit from the fun. From each fide of the bright light pre-
ceeded a bright ray, which had a double curvature very
diftin&, being firft convex towards the fun, and then concave.
The lower edge of thefe rays (or that neareft the fun), was
tolerably well defined, the upper edge melted away into the
fky, with a fort of ftreakinefs. They grew both narrower and
fainter towards their termination, and they reached pretty near
io the other cirele.
The whole form of this parhelion and its rays, bore fo
firiking a fimilitude to the body and extended wings of a long
winged bird, fuch as an eagle, hovering direéily over the fun,
that fuperftition would really have had little to add to the
image.
There was no trace of any other circle or arch in the heaveng,
nor of any anthelion.
It is probable, that it had been fill more beautiful before
I faw it, as during the time I obferved it, its brightnefs was
continually diminifhing; fome traces, however, were vifible
for nearly half an hour. .
The meafures which I have given muft be confidered as very
rough. I had no inftrument at hand, but a fix inch pocket
fe€tor. I held the joint of this as clofe to my eye as I could,
and opened it, till the points of the legs coincided with the
fun and with the circles that I wifhed to meafure. I am, how-
ever, inclined to think, that the meafures I have given are
true within a degree.
The accompanying fketch, (Plate III.) oy is drawn on
a {cale of 20° to an inch, from a rough draught which I made
at the moment, will give a more difiiné idea of the whole ap-
pearance than can be conveyed by words,
A Theory
56
Theory of halos
and parhelia.
Variable halos
produced by
equal drops.
The conftant
halo of 23° not
explained.
The hypothefis
of Huygens im-
probable.
ACCOUNT OF TWO HALOS,
A Theory of Halos and Parhelia. By Tuomas Youne,
IM 7b. Bo Re Ss.
The explanation of the primary and fecondary rainbow
begun by De Dominis, and completed by Defcartes and
Newton, derives an entire and fatisfaGtory confirmation, from
the perfeé coincidence of the obferved angular magnitudes,
with the refult of calculations of the effeét of {phericai drops,
We know that drops of water, either accurately, or very
nearly {pherical, exift in great abundance in every cloud, and
in every fhower of rain; and whatever their dimenfions may
be, they muft neceffarily confpire in the fame general effect, of
producing the fame rainbow, whenever a f{pectator is placed in
a proper fituation for obferving it; confequently fuch rainbows
are of very frequent occurrence.
I have attempted to fhow, that for producing the phenomena
of variable halos, often obfervable in hot climates, it is only
neceffary that a confiderable part of the {pherules of a cloud or
mift, be either accurately, or very nearly, of equal magnitude,
a condition, of which the poflibility is eafily admitted from
analogy, and the probability is favoured by the apparent unifor-
mity of the different parts of fuch mifts as we can examine.
But no fatisfaétory reafon has hitherto been affigned for
the production of the halo, which in thefe climates is the
moft common of all; that is, the conftant halo of 23° or 24°.
The hypothefis by which Huygens attempted to explain the -
produétion of halos and parhelia, are both arbitrary and im-
probable. He imagined the exiftence of particles of hail,
fome globular, others cylindrical, with an opaque part in the
middle of each, bearing a certain ratio to the whole; and he
fuppofed the pofition of the cylinders to be fometimes vertical,
and fometimes inclined to the horizon in a given angle.
It has already been obje&ted, that no fuch particles have
ever been obferved to accompany halos; and it is, befides,
highly improbable, that fuch an opaque part fhould bear the
fame proportion in all the hailftones, and that the cylinders
fhould have terminations fo peculiar as is fuppofed; and the
moft incredible circumftance of all is, that all thefe proportions
fhould be conftantly fuch, as always to produce a halo at the
diftance of 23° or 24° from the fun or moon.
. Tt
ACCOUNT OF TWO HALOS. 57
It appears, that a much fimpler and more natural expla-
nation of thefe phenomena may be deduced from the regular
cryftallization of fnow in the atmofphere.
Tit is well known, that the cryftals of ice and fnow, tend ah diaiile
always to form angles of 60°; now a prifm of water or ice, a iat erode
of 60°, produces a deviation of 23° 37’, for rays forming devi:tion of 23°
equal angles with its furfaces, and the angle of deviation eee
varies at firft very flowly, as the inclination changes, the flowly.
variation amounting to lefs than 3°, while the inclination
changes 30°.
Now if fuch prifms were placed at all poffible angles of in- The cafual ar-
clination, differing equally from each other, one half of them rine wale,
would be fo fituated, as to be incapable oftranfmitting any light the halo.
regularly by two fucceffive refraétions dire€ted the fame way ;
and of the remaining two fourths, the one would refra& all the
light within thefe three degrees, and the other would difperfe
the light in a {pace of between 20° and 30° beyond them,
In the fame manner, we may imagine an immenfe number Refraétion
of prifmatic particles of fnow to be difpofed in all polibie pte ear
direGtions, and a confiderable proportion of them to be fo greater halo of
fituated, that the plane of their tranfverfe feétion may pafs 47%.
within certain limits of the fun and the fpe@tator. Then halt
of thefe only will appear illuminated, and the greater part of
the light will be tranfmitted by fuch as are fituated at an an-
gular diftance of 23° 37’, or within 3° of it: the limit being
firongly marked internally, but the light being externally more
gradually loft. And this is precifely the appearance of the
moft common halo. When there is a fufficient quantity of the
prifmatic particles, a confiderable part of the light muft fall,
after one refraétion, on a fecond particle; fo that the effe@
will be doubled: and, in this cafe, the angle of retraétion
will become fufficient to prefent a faint appearance of colour,
the red being internal, as the leaft refrangible light, and the
external part having a tinge of blue.
Thefe concentric halos of 233° and 47°, are therefore fuf- Very fhort
ficiently explicable, by particles of fnow, fituated promifcuoufly okie
in all poffible ‘direQions. If the prifms be fo fhort as to form wife; and the
triangular plates, thefe plates, in falling through the air, i ont
tend to affume a vertical direction, and a much greater number give the hori-
of them will be in this fituation than in any other. The reflec ser eoas
tion from their flat furfaces will confequently produce a hori- tion 4 ey
zontal circle of equal height with the fun; and their refraGtion with wings,
will
5$ ACCOUNT OF TWO HALOS.
will exhibit a bright parhelion immediately over the fun, with
an appearance of wings, or horns, diverging upwards from
the parhelion.
Exp. with the For all fuch particles as are direéted nearly towards the
prifm. fpectator, will confpire in tranfmitting the light much more
copioufly than it can arrive from any other part of the circle ;
but fuch as are turned more obliquely, will produce a greater
deviation in the light, and at the fame time a defie@tion from
the original vertical plane. This may be eafily underftood, by
looking at a long line through a prifm, held parallel to it: the
line appears, inftead of a right line, to become a curve, the
deviation being greater in thofe rays that pafs obliquely with
re[peci to the axis of the prifm; which are alfo defleéted from
the plane in which they were paffing.
The line viewed through the prifm has no point of contrary
flexure, but if its ordinates were referred to a centre, as in
the cafe of the halos, it would aflume a form fimilar ito that
which Sir Henry Englefield has deferibed.
Tho’ fnow flakes The form of the flakes of fnow as they ufually fall, is in-
ee ae deed more complicated than we have been fuppofing, but
may be fimple in their elements in the upper regions of the air are probably
the upper more fimple. The coincidence in the magnitude of the
regionss &- ob ferved and calculated angles is fo ftriking, as to be nearly
decifive with refpeét to halos, and it is not dificult to imagine
that many circumftances may exift, whici may caufe the axis
of the greater number of the prifms to affume a pofition nearly -
horizontal, which is all that is required for the explanation of
the parhelia with their curved appendages. Perhaps alfo, the
effeét may fometimes be facilitated by the partial «melting of
the fnow into conoidal drops: for it may be thown, by the
light of a candle tranfmitted through a wine glafs full of water,
that fuch a form is accommodated to the produétion of an in-
verted arch of light, like that which is frequently obferyed te
accompany a pathelion,
A Defcription
POCTRINE OF PREPONDERANCE. 59
X.
A Defeription of Dr. Youne’s Apparatus for illufirating the
Doétrine of Preponderance*. Plate I. Fig. I.
AruoucH there can be no doubt of the truth of the “pparatus of
; 4 pullies for fhew-
mathematical conclufions, which have been deduced from the jng the mo ad-
well known laws of motion, refpeéting the moft advantageous vantageous em
employment of force in machines, yet they have, in general, blag 4)
been too little confidered in pra@tical works, and fcarcely ever
enforced by experimental illuftration. The apparatus con-
trived for this purpofe, has been mentioned in the account of
the leGures on mechanics ; its advantage is derived from the
fimplicity of its operation, and the facility of obferving at once
the feveral motions, which begin at the fame time, and may
eafily be compared, as long as they continue. The ratio of
the portions of the middle pulley, which is that of 5 to 2, is
near enough to the maximum (,/2 x 1): 13 and the other
ratios 3: 2 and 4: 1 are taken fufficiently different from this to
fhow that the velocity of each is inferior to that of the middle
pulley. The pulleys are all perforated in the axis, and move
freely on a ftrong polifhed wire, fupported by two fhort arms,
projecting a little from two upright pieces about three feet in
length, in order that the defcending weights may proceed
without interruption beyond the edge of the table,
—SE
An Account of an Experiment on the Velocity of Water flowing
through a Vertical Pipe. By the fame Author.
IT has been afferted by fome writers on hydraulics, and Whether the
Yenturi defcribes ticular experiment in fi atthe oer
u cribes a particular experiment in fupport of the water through
affertion, that the difcharge of water running out of the bottom a vertical pipe
. : : on from the bottom
of a ciftern, through a defcending pipe, is nearly the fame as oF o cifern be
if the ciftern were continued through the whole height, from the fame as
the furface of the water to the orifice of the pipe, and thefrom an hole in
: ‘ : a ciftern of the
water were then difcharged from the bottom of the ciftern by total depth.
a fhort pipe in any direGtion. The apparent difficulty of find-
ing a caufe adequate to the effect, on the one hand, and the
* In the leftures of the Royal Inftitution from whofe Journal
No. 11. the prefent and next articles are taken,
authority
60 CASE OF SPOUTING FLUIDS.
authority of Venturi on the other, made it defirable that the
experiment fhould be repeated ; and an apparatus Fig. III.
Plate I. was conftruéted, in the houfe of the Royal Inftitution,
for performing it in a fimple and fatisfa€tory manner. The
ciflern employed was a cube of nine inches: clofe to the
bottom a cylindrical tube was inferted, in a horizontal direc-
tion, nine inches in length, and half an inch in diameter; an-
other tube, of exaétly the fame dimenfions, was provided with
a flat funnel at its upper end, and its lower end was fitted to
flide inacollar placed in one of the upper angels of the ciftern,
Experiment fo that it was fupported in a vertical pofition. Water was
poured into the funnel, as faft as it could be tranfmitted through
the tube, and, as the furface of the fluid rofe in the ciftern, the
vertical tube was drawn up, fo that its lower orifice was barely
immerfed in the water. It was expected, that if the velocity
of the water in the vertical tube were equal to the velocity
correfponding to half its length, the water in the ciftern would
ftand at the height of four inches and a half, or one half of
that length, and that the preffure of this head of water would
generate, in the water flowing through the horizontal tube,
nearly the fame velocity as the column of water would acquire
in its defcent through the vertical tube: the friétion and
refiftance being in both cafes the fame.
fhewed thecon- But the refult was far different, and it fully confirmed thé
cae truth of the received theory: for the water rofe in the ciftern
to the height of eight inches, which was very nearly the length
of the tube. It is true that the water had already fome velocity
when it entered the funnel; but moft of this muft have been
loft by refleGion from its fides and bottom ; and the quantity .
of air bubbles, that were unavuidably carried down with the
water, muft have fully compenfated the little that remained.
The entire ad- ‘It appears therefore, that we are to confider this effeé in a
hering column in light fomewhat different from that in which it was placed in
sion ner 3 the leGlures on hydraulics. The water acquires all its velocity,
active upon the in confequence of the preffure of the atmofphere aéting jointly
ean a2 with its cohefion, in a very {mall fpace at the entrance of the
ducesthevame- tubel: confequently, during the whole time of its defcent it
effect as an head acquires no new motion, and the whole force of its gravitation
of that height. : ; :
muft therefore be at liberty to aét in any other way; hence the
whole column produces the fame degree of preflure as if it
were at reft, and caules the atmofphere to prefs on the water
above
SIMPLE EUDIOMETRIC APPARATUS. Of
above it in proportion to its whole height, in the fame manner
as if the preffure were derived in any other way from an equal
column of water; and the cafe is reduced to a perfe& analogy
with the preffure of a head of water of this height, fince the
air aGts upon the particles entering the tube in the fame man-
ner as the water does in more common cafes. Had the refult
of the experiment been different, it would have been an ex-
ception to the general principle of the prefervation of living
force, or the equality of the potential afcent to the aétual.
defcent; for, the water moving with the velocity due to half
the height only, would have been capable of afcending but to
half the height.
a S|
XI.
Account of a funple Eudiometric Apparatus conftructed and ufed
by Dr. T. C. Hope, FL R.S. Edin. &e. &e.
Since the difcovery of the uncertainty with which the ap- The uncertainty
plication of nitrous gas to atmofpheric air, and other mixtures °f eudiometrical
containing oxigen is attended, it has been found defirable to WER ee ae
prefent folid or liquid fubftances for the abforption of that prin- tenders the ufe
ciple. This on firft confideration may feem at leaft as eafy to Adib laances
be done as to mix two gafes ; but it is by no means fo, becaufe fary.
the liquids in particular poffefs a degree of chemical aétivity
which readers it inconvenient to immerfe the hands in them,
or to expofe their furface to the open air. Dr. Hope, whom
I had lately the pleafure of feeing in town, mentioned an ap-
paratus he ufes in his leétures and experiments, which is at
once fimple and effeétual, and I am happy in his permiffion to
defcribe it in this place,
A Fig. 3, Plate IV. reprefents a bottle which may be 12 Apparatus by
inch in diameter, and 22 inches in length, having a neck and nip pay
ftopper at D, and another neck as ufual at C, into which laft without incon-
the neck of the bottle or body B, is fitted by grinding. This venience.
laft was made of the fame diameter as the bottle, but feven or
eight inches long. B contains the gas, and A the liquid; for
example, folution of hydrofulphuret. When B is thus con-
neéted with A, the compound veffel may be inverted and agi-
4 tated ;
62
The apparatus
fimply ind
highly conve-
ricnt.
Metals burned
in nitrogen, &c.
by galvanifm. -
ReduGion of
titanium.
SCIENTIFIC NEWS.
tated ; and the liquid will flow into B, where it will abforly
the oxigen, and form a partial vacuum. If this circumftance
be found, or apprehended, to prevent the complete or rapid abs
forption, the veffel A may be plunged beneath the furface of
common water, and the ftopper D flowly opened. The pref-
fure of the atmofphere will then force in a quantity of water,
which will dilute the hydrofulphuret, but not fufficiently te
prevent the completion of the procefs. The veffel B muft be
graduated to fhow the dimenfions of the refidue, or otherwife
this refidual gas may be transferred into a veffel exprefsly gra-
duated for meafuring gafes.
By this fimple and elegant apparatus we fee that the liquid
is economized, and the facility, neatnefs, and precifion of ex-
periment infured. The fize here mentioned is very well
adapted to the purpofes of public demonftration; but it is
almoft needlefs to remark, that it may be made confiderably
f{maller without depriving it of its utility and excellence.
P. S. While reading this proof, I have received a line from
Dr. Hope, by which I am very forry to find that the fketch I
have given is not accurate; but as it is now late in the month,
and the figure is engraved, I fhall be careful to give another
engraving with the obfervations he may favour me with. W. N.
SCIENTIFIC NEWS.
Combuftion of Metals in non-refpirable Gafes, by means of Gal«
vanifin.®
Proressor Tromfdorff has noticed that metals are come
buftible by means of the galvanic {park in hidrogen, ammo-
nia, nitrogen, nitrous and carbonic acid gafes,
Reduction of the Oxide of Titanium.
Profeffor Lampadius has fucceeded in reducing to the me-
tallic flate by means of charcoal only, the oxide of titanium,
obtained by decompofing the gallate of titanium by potafh or
foda. The metallic titanium is of a dark copper colour; it
* Tromfdorff’s Hiftory of Galvanifm and its chemical agency,
p> 122,
has
SCIENTIFIC NEWS. 63
has much metallic brilliancy, is brittle, and poffeffes in {mall
{eales a confiderable degree of elafticity. It tarnifhes on ex-
pofure to air, and becomes eafily oxided by heat. It then
acquires a blueifh afpect. It detonatés with nitrate of potafh,
and is highly infufible. All the denfe acids aét upon it with
confiderable energy. Scherer’s Journ. 1X. p. 49. p. 72+
On the Precipitability of the Oxide of Bijmuth.
Mr. Buckholtz has found that the folution of bifmuth pre- Solution of bife
pared in the cold is alone decompofable, by a’ copious addition muth by heat not
of water, but that no fuch effect takes place in the folution aa ae
prepared by means of heat. He has alfo noticed that a folution
of this metal prepared in thec olde, depofits its oxide ina cryf-
talline form merely by warming the folution gradually.
Scherer 1X. p. 73.
New Method of preparing phofphate of Soda.
Mr. Funcke, apothecary at Linz, inGermany, has difcovered Preparation of
a new method of preparing phofphate of foda, in a more at of
economical, expeditious and eafy manner, than any of the
proceffes hitherto made ufe of by manufaéturers or chemifts.
His procefs confifts, in faturating the excefs of lime contained
in calcined bones with dilute fulphuric acid, and then diffolv-
ing the remaining phofphate of lime in nitric acid. To this
folution, he adds a like quantity of fulphate of foda, and then
recovers the nitric acid by diftillation. The phofphate of foda
is then feparated from the fulphate of lime, by the affufion of
water, and cryftallization in the ufual manner. Scherer IX. 59.
REMARK BY THE TRANSLATOR. (A.)
This procefs feems to be much preferable to that now in ufe,
viz. to decompofe the bones of animals burned to whitenefs, by
fulphuric acid, and then prefenting foda to the difengaged phof-
phoric acid. For the phofphate of lime cannot be completely
decompofed by the affufion of fulphuric acid ; on account of
this acid forming inftantly a portion of fulphate of lime: the
liberated phofphoric acid then produces with the remaining
undecompofed portion of phofphate of lime, a fub-phofphate of
lime, which cannot be decompofed by fulphuric acid, and which
together with the fulphate of lime already produced, forms an
3 unmanageable
64 SCIENTIFIC NEWS.
unmanageable and bulky mafs. And again if to this mafs,
wafhed out with water as well as poffible, carbonate, of foda
be now prefented, a partial decompofition will only be effeéted,
for it is the excefs of the phofphoric acid of this falt only,
which in that cafe forms the article fought. The remaining
portion of phofphoric acid remain united to the lime, in the
form of phofphate of lime. The above procefs is therefore
evidently better.
Sulphate of Soda prepared from Sulphate of Lime.
Sulphate of foda This method confifts in making into a pafte witha {ufficient
from gyplum. quantity of water, eight parts of burned.gypfum, or fulphate
of lime, five of clay, and five of common falt. This mixture
is burned ina kiln or other convenient oven, and then ground
to powder, diffufed in a fufficient quantity of water, which
after being ftrained and evaporated, is fuffered to cryflallize.
Scherer 1X. 61.
A
JOURNAL
OF
NATURAL PHILOSOPHY, CHEMISTRY,
AND
TAE . ARDS.
OCTOBER, 1803.
ARTICLE «I.
Analyfis of the Egyptian Heliotropium; a Mineral lately imported
from that Country. By Frepericx Accum, Praétical
Chemift, and Teacher of Chemifiry. Communicated by the
Author.
A PARTICULARLY beautiful {pecies of filicious ftone Beautiful filice-
has lately been imported from Egypt, which was ftated in the 04S fone of a
green colOur
letter of the perfon who fent it, to poffefs the peculiar property ane Egypte
of refle€ting the rays of the fun red, when immerfed in water ;
and when taken out of this fluid to exhibit the figures of the
fun and of the moon, when viewed in a particular direétion.
But as none of the purchafers of this mineral could make out
thefe fingular properties, the price fixed on the article was
confiderably diminifhed, and the ftone fold at a cheap rate,
The beautiful green colour which it: poffeffes, and the capabi-
lity of receiving a high polifh, together with the facility of
cutting it, has neverthelefs rendered it a convenient article for
being worked into different objeéts of fancy and ornament.
The colour of this ftone is a fine apple-green. It is very External appear-
hard, and cannot be fcratched, but with the point of a good f2°° andere
pen-knife. Its fraéture is even and free from all afperities.
It breaks with very fharp edges, and its texture is very com-
paét. It is femi-tranfparent when in pieces not exceeding halfan
Vor... VI.—OcrToseEr, 1803, F inch
66 EGYPTIAN HELIOTROPIUM.
inch in thicknefs. It ftrikes fire with fteel, and breaks into
acute angular irregular pieces. Its fpecific gravity is 2,708.
The ftone is fold by the venders by the name of Egyptzan Heli
otropium. Its nature will be more clearly deduced from the
following examination :
Analyfis.
Analyfis. An entire polifhed piece of the ftone, weighing 250 grains,
ee prea was expofed to a white heat, ina wind-furnace, for two hours,
sherri with and then fuffered to cool. The original green colour of the
white and yellow mineral, was changed during this procefs to a chocolate brown,
ine eas with fnow white and lemon yellow veins, The polith of the
1-21f part. {tone was not injured, but its weight was diminifhed 12 grains.
Diffufion of the Five hundred grains of the ignited ftone were finely pulver-
powdered ftone jzed, and mixed with 2000 grains of potafh, diffolved in alike
in fourparts pot- : eee Ri he aq d (;
afh, fufion, fo- Quantity of water. This mixture was evaporated to drynefs
lution of the in a crucible of platina, and expofed to heat, gradually in-
mafs in watery Greafed to whitenefs, for one hour. During this operation the
yather turbid. : : : Bh
mixture fufed quietly, and exhibited when cold, a homogene~
ous opake mafs, of a reddifh colour. This mafs was covered
with water, and after having been expofed to a gentle heat, a
folution of it was effeéted in that fluid.
Saturated with This alcaline folution was a little turbid, and could. not be
eohain dv isi rendered tranfparent by repeated filtration. I faturated it with
Dilution with muriatic acid, a white precipitate fell down, the whole.fluid
waters acquired a reddifh hue, and affumed a gelatinous confiftence.
The latter could but difficultly be dimmifhed, by a copious ad-
mixture of water.
Evaporation In order to colleé the precipitate which was diffufed through
nearly todry- the fluid, the whole was evaporated nearly to drynefs, and then
nefs, addition of = ; Pane ; A :
dilute muriatie transferred into muriatic acid, diluted with fix times its quan-
- Stags tity of water, and afierwards filtered. The precipitate, after
ate LLeXs e wi? . 5 ° °
: having been wathed, dried, and ignited, weighed 365 grains.
It was pure filex. ; By iL
Refidual fluid The fluid trom which thefe earths had been feparated, to-
eoncenirated - gether with the water expended for walhing it, I concentrated
costa by evaporation to about + Of its original bulk, and then fatu-
of :potath. rated it with aheated folution of carbonate of potath in excefs.
_ The white precipitate which was depofited, I transferred into
a tik containing muriatic acid; a brifk effervefcence enfued,.
but no perfect folution could be effe&ed, by either this, er any
other
ae
EGYPTIAN HELIOTROPIUM, 67
‘ether acid employed. It was therefore filtered, and the info-
luble part collected: This infoluble refidue was of a fine red Infoluble (red)
colour, and harfh to the touch. It weighed 22 grains. But Portion boiled
E i nee MO): ’ with muriatic
after having been boiled in muriatic acid; it loft $ grain, and acid gave a little
acquired a perfeét white colour. The acid made ufe of for iron» andleft
. . . AICX»
that purpofe proved to have {tripped it of iron to that amount.
It was therefore a portion of filex which had eluded the firft
procefs employed for feparating this earth. _
The muriatic folution from which this filicéous éarth had The faft muria-
been feparated, I mingled with a folution of carbonate of t< lution
: i a treated as before.
potafh, till no further turbidnefs enfued: ‘The obtained pre-
cipitate was transferred after repeated ablutions in water, into
a boiling folution of potath, and digefted in that fluid for one
hour. The mixture was then diluted with water, and the in-
foluble part feparated by the filtre.
The alcaline folution was faturated with muriatic acid, and The alcaline fog
decompofed by carbonate of ammonia in excefs; the precipi- tion was de-
| ; q x compofed by
tate obtained by this means, after having acquired a confider- carbonate of ame
able confiftence, was digefted in acetous acid, and examined eae and di-
. € Cce=
for magnefia, but no veftige of fuch earth could be deteéted ae .
Tt was therefore dried and ignited, its weight amounted to 204 and the {olution
: contained no
grains. ae ; magnefia, but
The infoluble refidue from which this earth had been fepa- only alumines
rated, was again diffolved in muriatic acid, and into this folu- st sat as
: He. Wee . : aken up by t
tion I dropped liquid ammonia till the odour of the latter con- sc-tous seid oe
fiderably predominated. A brown flocculent precipitate fel] again diffolved .
down, which was collected, wafhed in liquid ammonia, and pee te iad
boiled for a few minutes in a folution of potafh. It was then excefs of ammo-~
P :
transferred into a {mall retort, and nitric acid affufed upon it, his jean
which was again diftilled off from it repeatedly. The retort after perfe@ fe-
was laftly heated to a dull rednefs. The precipitate now P*ation of all
‘ z acid, and com~=
weighed 29 grains. plete oxidation
The fluid from which this precipitate had been obtained, by ae :
together with the folution of potath made ufe of for boiling it, a eid
was then mixed with muriatie acid, and afterwards decompofed The fluid from
; a : which the iron
by the addition of carbonate of potath. The product obtained, nated fens
eflervefced with muriatic acid, and yielded fulphate of lime on rated was mixed
eflaying a fmall quantity of it by fulphuric acid. It was theres With mur. acid
: . Rene E and decompofed
fore dried, and expofed toa white heat, after which its weight by carb. potath.
was 56% grains, Lime fell down.
F2 The
“at
6s EGYPTIAN HELIOTROPIUM.
The refiduary fluid was further examined in the ufual man='
ner, but no other fubftance could be found, but what had been
introduced during the different procefles made ufe of in this
examination, The analyfis of the mineral being therefore
compleated, from which it appears that 500 grains of the
Egyptian heliotropium contain,
Component Silex - - - - - 365 grains
parts of Egyp- Alumine - - = = 205
tian heliotropi- Oxide of Iron 4 G ae 29 &
um.
Lime jo senility ssiv be 56%
Water - - sii Mugs) 1a
495
Lots” «75
500
Old Compton-Street, Soho,
Sept. 8th, 1803.
P. §. In my paper on the compound of phofphorus and ful-
phur in your laft Journal (Auguft) I obferve a typographical
error, p. 5.1. 22. which materially affeéts the fenfe, and which
I will thank you to correét, namely, for 3, read =, part.
FA.
II.
Method of clofing wide mouthed Veffels intended to be kept from
communicating with the Air. Ina Letter from ANTHONY
Caruisie, Efq.
To Mr. NICHOLSON
Dear Srr,
Clofure of wide Gy is frequently defirablesto clofe the openings of wide-mouths
sonia ik ed veffels intended to contain fubftances which would be in-
tomical prepara-jured by free expofure to the atmofphere, or to evaporation.
ie ar The prefent obfervations, however, originate in attempts made
to improve the art of preferving anatomical preparations.—:
The moft ufual liquids employed for what are termed “ wet
preparations,” are weak ardent fpirits, and diftilled oil of tur-
pentine,
METHOD OF CLOSING WIDE-MOUTHED VESSELS. 69 —
pentine, to which may be added an aqueous folution of hy-
drargyrus muriatus, or mercury corrofive fublimate in the pro-
portion of twenty grains of the latter to a pound of pure water.
The methods ordinarily adopted for clofing glafs veffels ufed Ufual methods.
for thefe purpofes, have been ground glafs ftoppers, well
foaked bladders with a middle plate of thick fheet lead, to
keep the top level, and plates of glafs luted with glaziers
putty.
The objeétions to thefe methods are found by experience to Obje@ions to
be fufficient to induce the trial of others. The ground glafs each feverally.
ftoppers are feldom air-tight, but when they are, it happens
that by the accumulating of particles of duftin the fitting, the
ftopper becomes in a few years immoveable. Where oil of
turpentine is employed, the {topper becomes fixed by hardened
turpentine. The ftopping with bladders and fheet lead is li-
able to fuch repeated changes of preffure within and without,
by the alterations in the expanfion of the contained liquids from
variations of temperature; that the cohefion of the bladders
are eventually deftroyed ; add to this, that fuch preparations
cannot be taken out of the veffels for examination, or the li-
quor renewed, without the trouble of a new ftopping. The
plate of glafs with putty is feldom air tight, but when it is fo,
the ftopping is liable to the fame objeétion which was ftated
laftly againft the bladders.
The method [ have now adopied, is to have a glafs jar with New ae by
a groove half an inch deep round the outfide of the top or ae ake
mouth, and a glafslid, like that ufed by confeétioners in their into a groove
fhow glaffes, the lid fitting loofely into the groove is rendered baniual eae
air tight by hog’s lard, a fubftance never quite fluid at the
higheft temperature of this climate, and always foft enough in
the cold feafon to admit of removing the lid or top.
The firft glafs of this kind was made to my order by Mr,
Parker in Fleet-ftreet, to contain twenty ounce meafures of
water, and the coft was five fhillings. A fimilar adjuftment
for the lids of earthen jars, to contain pickles, preferves, &c.
feems both eligible and eafy in practice. See Plate V. Fig. 2.
Iam,
Dear Sir,
Your obliged Friend,
A. CARLISLE.
Soho-Square.
Extrad
70
Catt iron lying
thirty years at
the bottom of
the fea was ox-
ided,
Not uni-
formly, but in
yeins.
A cannon funk
ina fhip burned
at the evacua-
tion of Toulon
was oxided only
in the middle.
CHANGES OF CAST IRON.
iif.
Extra& of a Letter from Toulon to General le Vavaffeur, Infpector
of the Materials of the Guns of the French Navy, on the Changes
which Caft Iron undergoes by remaining long in the Sea.*
An obfervation I have never heard explained is, that caft
iron, which has lain a long time at the bottom of the fea, is
not equally oxided throughout. I formerly faw acannon weigh-
ed up, .after it had been funk thirty years, which was fo much
oxided in veins, that I could run a knife into fome places,
while the metal clofe by was impenetrable; and on carrying
the knife beyond this hard vein, it entered as before. A gun
has juft been weighed up here (at Toulon,) belonging to one
of the thips burnt when the Englifh evacuated the city, The
middle is fo uniformly oxided, that a large piece may be cut —
off witha hatchet. ‘Toward the breech, and toward the mouth,
the metal appears to have loft nothing of its hardnefs. Can
this difference be afcribed to the contaét of the fubftances in
which the gun was buried underneath the water? Its pofition
at the bottom of the fea not being known, we can form no cane
jectures on this point. For my part [had imagined, from the
hard veins of the cannon mentioned above, that its metal had’
intermixed with it fubftances on which falt water could not
act. The gun lately taken out of the fea appeared more ho-
mogenous, but I cannot frame any fatisfactory explanation of
the faét.+
* Annales de Chimie, V. 139. ;
+ It is probable, that the laft cannon, as it belonged to a fhip
that was burned, had part of it heated to fuch a point, when it.fel]
into the fea, as would occafion it to be oxided in a higher degree
than the others. It appears to me, more difficult to explain the
different veins exhibited by the former cannon. Note of General
le Vavaffeur., | ,
IV. On
ANTIQUITY OF THE INVENTION OF GUN-POWDER, 71
IV.
On the Antiquity of the Invention of Gun-powder, and its firf? Ap-
plication to Mihtary Purpojes. By Mr. Wirc ies.*
THe period of the invention of Gun-powder, and its firft
application for the purpofe of artillery, has not yet been accu-
rately afcertained, Though there are many accounts which
have been given concerning the invention of this deftructive ;
compound, yet none of them ftate their authorities. The un-
certainty concerning the invention of gun-powder feems merely
to be owing to the want of proper documents. The moft Hiforical faés
fummary accounts the author of this paper could find, are con- papal
tamed in two Effays, the one written by Gram, the other by gunpowder, and
Tremler. The firft account contains the hiftory of the inven, its ule in war.
tion of gun-powder in Europe, and its firft application in
Denmark ; the latter comprehends both the invention of pow-
der, and the ufe of guns among the Europeans,
According to the opinion of Gram, gun-powder was al-
ready known in Europe about the year 1340. Tremler, on the
contrary, endeavours to prove, that no author of credit has
pofitively fhewn that it was known before the year 1354.
Thefe authors, therefore, differ only 14 years, refpe@ing the
period of the invention. Being the other day, fays Mr.
Wiegleb, in fearch of fome documents depofited in the ar-
chives of this town (Langenfalze), I happened to meet with
ihe annual account of the expences of the town for the year
1378. This account contains a fpecification of different arms,
viz. pikes, bows, crofs-bows, arrows, guns and gun-powder.
The following articles particularly fixed his attention :
1. One gun. 2. One gun andonecharge of lead. 3. One
gun and one charge of lead, 4. Two guns and two charges
of lead. 5, One gun and one charge of lead. 6. Two
guns and three charges of lead. Befides thefe articles, the
following charge was made in the account ;
Pro Pulveribus, 35 thillings,
Pre Pulveribus quos domini emerunt ad Pyxides, 3 fhillings,
Pro duabus Putellis ad Pyxides, 3 fhillings.
© From the German of Crell’s Annales, ve xx. Pe 6.
tf
\
72 ANTIQUITY OF THE INVENTION OF GUN-POWDER,.
Hittorical fats If we confider that guns, powder, and lead, are here
a. determine th€ charged, it is obvious that by the word pulvis, gun-powder
rf invention of i
unpowder, and muft be underftood ; and by patellis, guns muft be meant.
its ufe in war’ From thefe documents we are led to believe that guns and
gun-powder were known already before the year 1378. And
it is more than probable that they were not purchafed that
year, but had probably been ufed before that time. For guns
were too expenfive for fingle individuals and fmall towns at
that time; and on that account, the place in which I met
with the faid documents was very probably provided with
guns many years after the invention of them. That this muft
have been the cafe becomes obvious from the following ob-
fervation: Achilles Gefner, the Hiftorian of Augfburg, who
wrote a Latin Chronicle at the beginning of the 16th century,
fays,* ‘* Three large cannons were caft at Augfburg in the
“ year 1378, the largeft of which difcharged a ball of 127
“¢ pounds ; the fecond a ball of 70 pounds, and the third a
«« ball of 50 pounds, at a diftance of 1000 paces.”
Herman Corner, who lived at the end of the 14th century,
relates that the inhabitants of Lubec affifted the Emperor
Charles, who befieged the caftle of Dannenberg, with 600
armatis cum duabus machinis. Bombardae enim pro tunc non
erant tta communes, utt nunc funt: From hence it is evident
that the 600 machines were nothing but bombardae, or guns.
Another remarkable document the author of this paper met
with was the fentence of death of Nicolaus the Bold, who
fupplied the enemy with two barrels of gun-powder, in the
year 1372. In this fentence it is clearly expreffed, that the
gun-powder was made up of faltpetre and fulphur. In the
fame year, the Corporation of Augfburg ordered to have caft,
twenty cannons of metal, at the great expence of fifty pence,
Thefe cannons were intended to be ufed againft their neigh-
bours, the Bavarians.
Petrarch, born 1304, ftates, in his work + publifhed 1374,
Gav. Habeo machinas, ingentia fuxa torquentes.
Rav. Saxa torquere furiofum eft.
Gav. Habeo machinas et balliftas innumeras.
Raz. Mirum nifi et glandes Aeneas quae flammis ejectis hor=
rifon sone tru jacuntur. Non erat fates de coelo tonantes ira
* Annales Augfburgenfes.
+ De Remediis utriu{que fortunae,
4. Dei
ANTIQUITY OF THE INVENTION OF GUN-POWDER. 713
Dei immortalis, homuncio? O credulitas junéia fuberbiae. De Hiftorical fa&s
terra etiam tonuzfet : Non immutabile fulmen ut Maro ait humana parents
rabies tmmitata eft, et quod e nubibus mitt? folet, ligneo quidem, gunpowder, and
fed tartareo mittitur infrumento, Evat haec pefiis nuper rara ut is ¥f& in ware
cum ingenti miraculo cerneretur, nunc ut rerum pefimarum do-
ciles funt anime, ita communis eft ut unum quodlibet genus ar-
morum.
We fhall be lefs furprifed that cannons and guns were made
of wood ; even inthe 15th century guns were bound with
iron hoops. :
In the year 1365, Margraff Frederick, of Meiffen, at-
tempted to ftorm the town and caftle of Einben with flings,
battering rams, and other machines, then made ufe of in be-
fieging towns. Rothe, who mentions this in his Chronicle
of Thuringen, farther relates that the Duke Albert was in
poffeffion of a gun which he himfelf ufed at the fiege, for
fhooting into the works of the enemy. It was, fay this author,
the firft gun ever feen in that country.
In another document is ftated, that anno Domini, millefimo
tricentefimo fexayefimo, confiftortum urbis Lubecenfis in toto com-
bujfium eft, per negligentiem illorum qui pulveras pro bombardis
parabant. | The fame fire is mentioned by Herman Corner,
a. native of Lubeck. His words, as taken from the Chronicle
‘of Lubeck, are as follows: Con/fiftorium urbis Lubecenfis incen-
Sum eft, et combuftum per negligentiam illorum qui pulveres pro
bombarbis, five petraries parabant, fecundum Chronicam Lube~
cenfem. Cum enim praedictas parafent locabant cos in quodam
loco confiftoris non caute cuftoditos ab agne. Pulveres ergo per incue
riam noéte accenfiy domum ipfam fuccenderunt, ad antequam ex-
tingut potuiffent, ewm in cineres redegerunt, Confequently gun-
powder muft have been prepared already at Lubeck about the
year 1360.
In the year 1359, a war broke out between the kings of
Caftile and Arragonia; in which the latter made ufe ofa
large gun, with which he did much damage to the veffels of
the king of Caftile ; for he fhot down with it the mafts and
rigging, and killed many men by only two fhots.
Peter Divacus commemorates, that in the year 1356 the
inhabitants of Lyons in Brabant purchafed 12 guns (bombar-
.dae) which were called thundering guns, or blunderbuffes, -
ab horrendo fragore.
74
Refearches of
Bergman on
Calamines.
Hauy’s opinon
that they are
pure oxides,
‘Experiments,
ony
Calamine from
Bley berg.
External cha-
racterse
CHEMICAL ANALYSIS OF SOME CALAMINES.
Vv.
4A Chemical Analyfis of fome Calamines. By JAMES SMITHSON,
Esa. F.R.S. P.R.S. From the Philofophical Tranfac-
tions for 1803.
NorwitHsta NDING the experiments of Bergman and
others, on thofe ores of zinc which are called calamine, much un-
certainty ftill fubfifted on the fubjeét of them. Their conftitution
was far from decided, nor was it even determined whether all
calamines were of the fame fpecies, or whether there were {fe-
veral kinds of them.
The Abbé Hauy, fo juftly celebrated for his great oan:
ledge in cryftallography and mineralogy, has dhe: in his
late work *, to the opinions he had before advanced +, that
calamines were all of one f{pecies, and contained no carbonic
acid, being a fimple calx of zinc, attributing the effervefcence
which he found fome of them to produce with acids, toan ac-
cidental admixture of carbonate of lime.
The following experiments were made to obtain a more
certain knowledge of thefe ores; and their refults will: thow
the neceflity there was for their farther inveftigation, and how
wide from the truth have been the opinions adopted con-
cerning them.
Calamine from Bleyberg.
a. The fpecimen which furnifhed the fubjeét of this article,
was faid by the German of whom it was purchafed, to have
come from the mines of Bleyberg in Carinthia.
It was in the form of a fheet ftalactite, fpread over fmall
fragments of limeftone. It was not however at all cryftalline,
but of the dull earthy appearance of chalk, though, on coms
parifon, of a finer grain and clofer texture.
It was quite white, perfectly opaque, and adhered to the
tongue; 68.0 grs. of it, in fmall bits, immerfed in dittilled
water, abforbed 19.8 grs. of it, = 0,29.
It admitted of being {craped by the nail, though with fome.
difficulty: fcraped with a knife, it afforded no light.
® Traité de Mineralogie, Tome 1V. + Fournal des Mines. Noi 32.
6$.1 grs. |
e
CHEMICAL ANALYSIS OF SOME CALAMINES, 75
68.1 grs. of it, broken into fmall pieces, expelled 19.0 grs, Specific gravity.
of diftilled water from a ftopple bottle. Hence its denfity
= 3.584. In another trial, 18.96 grs. at a heat of 65° Fahren-
heit, difplaced 5.27 grs. of diftilled water; hence the denfity
= 3.598. The bits, in both cafes, were entirely penetrated with
water. :
b. Subjeéted to the aétion of the blowpipe on the coal, it be- Blowpipe affays«
came yellow the moment it was heated, but recovered its priftine
whitenefs on being let cool. This quality, of temporarily
changing their colour by heat, is common to moft, if not all,
metallic oxides ; the white growing yellow, the yellow red, the
red black.
Urged with the blue flame, it became extremely friable ;
fpread yellow flowers on the coal; and, on continuing the fire
no very long time, entirely exhaled. If the flame was direéted
againft the flowers, which had fettled on the coal, they fhone
with a vivid light. A bit fixed to the end of a flip of glafs,
watted nearly as quickly as on the coal.
It diffolved in borax and microcofmic falt, with a flight
effervefcence, and yielded clear colourlefs glaffes ; but which
became opaque on cooling, if over faturated. Carbonate of foda
had not any action on it.
ce. 68.0 grs. of this calamine diffolved in dilute vitriolic acid Solutions in the
with a brifk effervefcence, and emitted 9.2 grs. of carbonic icone Denk
acid. The folution was white and turbid, and on ftanding gave only falts of
depofited a white powder, which, colleGted on a {mall filter pe Le
‘ of gauze paper, and well edulcorated and let dry, weighed
only 0.86 grs. This fediment, tried at the blowpipe, melted
firft into an opaque white matter, and then partially reduced
into lead. _ It was therefore, probably, a mixture of vitriol of
lead and vitriol of lime.
The filtered folution, gently exhaled to drynefs, and kept
over a fpirit-lamp till the water of cryftallization of the falt and
all fuperfluous vitriolic acid were driven off, afforded 96.7 grs,
of perfectly dry, or arid*, white falt. On re-folution in water,
and cryftallization, this faline matter proved to be wholly vitriol
* Dry, as oppofed to wet or damp, which are only degrees of
each other, merely implies free from mechanically admixed water.
Arid, may be appropriated to exprefs the ftate of being devoid of
combined water,
of
~I
Dy
The calamine
contained oxide
of zinc, car-
bonic acid, and
water,
Somerfetthire
calamine.
CHEMICAL ANALYSIS OF SOME CALAMINES.
of zinc, excepting an inappretiable quantity of vitriol of lime in
capillary cryftals, due, without doubt, to a flight and accidental
admixture of fome portion of the calcareous fragments on which
this calamine had been depofited. Pure martial pruffiate of
tartar, threw downa white precipitate from the folution of this
falt.
In another experiment, 20.0 grs. of this calamine afforded
28.7 grs. of arid vitriol of zinc.
d. 10 grs. of this calamine were diffolved in atidaat marine
acid, with heat. On cooling, fmall capillary cryftals of muriate
of lead formed in the folution. This folution was precipitated
by carbonate of foda, and the filtered liquor let exhale flowly in
the air; but it furnifhed only crvftals of muriate of foda.
e. 10 grs. diffolved in acetous acid without leaving any refi-
duum. By gentle evaporation, 20.3 grs. = 2.03. of acetite of
zinc, inthe ufual hexagonal plates, were obtained. Thefe cryf-
tals were permanent in the air, and no other kind of falt could
be perceived amongft them.
Neither folution of vitriolated tartar, nor vitriolic acid, occa-
fioned the flighteft turbidnefs in the folution of thefe cryftals,
either immediately or on ftanding ; a proof that the quantity of
lime and lead in this folution, if any, was exceffively minute.
f. A bit of this calamine, weighing 20.6 grs. being made red
hot in a covered tobacco-pipe, became very brittle, dividing on
the flighteft touch into prifms, like thofe of ftarch, and loft 5.9 |
grs. of its weight = 0.286. After this, it diflolved flowly and
difficultly in vitriolic acid, without any effervefcence.
According to thefe experiments, this calamine confifts of,
Calx of zinc - - - 0.714
Carbonic acid - - = 0.135
Water - “ - 2 OSE
1.000.
_ The carbonates of lime and lead in it are more accidental
admixtures, and in too fmall quantity to deferve notite.
Calamine from Somerfetfhire.
a. This calamine came from Mendip Hills in Somerfethhire.
It had a mammillated form ; was of a denfe cryftalline tex-
ture ; femitran{parent at its edges, and in its fmall fragments ;
and upon the whole very fimilar, in its general appearance, to
calcedony.
Tt
CHEMICAL ANALYSIS OF SOME CALAMINES. Va
It was tinged, exteriorly, brown ; but its interior colour was
a greenifh yellow.
It had confiderabie hardnefs; it admitted however of being Charaéters.
{craped by a knife to a white powder.
56.8 grs. of it difplaced 13,1 grs. of water, at a temperature
of 650 Fahrenheit. Hence its denfity = 4.336.
b. Expofed to the blowpipe, it became opaque, more yellow, Blowpipe affays,
and friable; {pread flowers on the coal, and confequently vola-
tilized, but not-with the rapidity of the foregoing kind from
Bleyberg . .
It diffolved in borax and microcofmic falt, with effervefcence,
yielding colourlefs glaffes. Carbonate of foda had no aétion
on it,
c. It diffolved in vitriolic acid with a brifk effervefcence ; eshitens
and 67.9 grs. of it emitted 24.5 grs. = 0.360, of carbonic acid.
This folution was colourlefs; and no refiduum was left. By
€vaporation, it afforded only vitriol of zinc, in pure limpid
cryftals, "
d. 23.0 grs. in {mall bits, made red hot ina covered tobacco-
Pipe, loft 8.1 grs. = 0.352. It then diffolved flowly and diffi-
cultly in vitriolic acid, without any emiffion of carbonic acid ;
and, on gently exhaling the folution, and heating the falt ob-
tained, till the expulfion of all faperabundant vitriolic acid and
all water, 29.8 grs. of arid vitriol of zinc were obtained. This
dry falt was wholly foluble again in water ; and folution of pure
martial pruffiate of foda occafioned a white precipitate in it.
This calamine hence confifts of, - Component
Carbonic: acid fe - « 0.352 parts, Carboni¢
‘ . acid and oxide
Calx of zinc - . 4 - 0.648 of zinc.
1.000.
Calamine from Derbyfhire.
a. This calamine coafifted of a number of fmall cryftals, Derbymire cas
about the fize of tobacco-feeds, of a pale yellow colour, which one
appeared from the fhape of the mafs of them, to have been
depofited on the furface of cryftals of carbonate of lime, of
the form of Fig. 28. Plate IV. of the Criftallographie of Romé
de L’Ifle,
The fmallnefs of thefe calamine cryftals, and a want of External cha-
fharpnefs rendered it impoffible to determine their form with ers, &c.
cetlainty :
78 CHEMICAL ANALYSIS OF SOME CALAMINES¢
certainty; they were evidently, however, rhomboids, whofe facée
were very nearly, if not quite, rectangular, and which were in-
complete along their fix intermediate edges, apparently hke
Fig. 78. Plate IV. of Romé de L’Ifle.
22.1 grs. of thefe cryftals, at a heat of 57° Fahrenheit, dif-
placed 5.1 grs. of water, which gives their denfity = 4.333.
Heat did not excite any eleétricity in thefe cryftals.
b. Before the blowpipe, they grew more yellow and opaque,
and fpread flowers on the coal. They diffolved wholly in borax:
and microcofmic falt, with effervefcence.
¢. 22.0 grs. during their folution in vitriolic acid, effervefced,
and loft 7.8 grs. of carbonic acid = 0.354. This folution was
colourlefs, and afforded 26.8 grs. of arid vitriol of zinc, which,
rediffolved in water, fhot wholly into clear colourlefs prifms of
this falt,
Component | d. 9.2 grs. of thefe cryftals, ignited in a covered tobacco-
parts carbonic
acid and oxide of P'pe, loft 3.2 grs. = 0.3478 ; hence thefe cryftals confift of,
zinc. Carbonic acid - - - 0.348
Calx of zinc + ml git - 0.652
Experiments.
1.000.
Eleé&trical Calamine.
EleGrical ca- = The Abbé Hauy has confidered this kind as differing from
lamine from c 2 : ea ree Saw ary
Rerbania. the other calamines only in the circumftance of being in diftinét
cryftals; but it has already appeared, in the inftance of the
Derby thirecalamine, that allcryftals of calamine are not eleétric’
by heat, and hence, that it is not merely to being in this ftate
that this fpecies owes the above quality. And the following
experiments, on fome cryftals of electric calamine from Reg-
bania in Hungary, can leave no doubt of its being a com~
bination of calx of zinc with quartz; fince the quantity of quartz
obtained, and the perfe@t regularity and tranfparency of thefe
cryftals make it impoffible to fuppofe it a foreign admixture in
them. .
a. 23.45 grs. of thefe Regbania cayftals, difplaced 6.8 grs.
oe diftilled water, from a ftopple-bottle, at the temperature ee
° Fahrenheit; their fpecific gravity is therefore = 3.434.
he he form of thele cryftals is reprefented in Figure I, Plate
V. where the angle formed by the planes a and c was 90°, that
by a and e = 150°, a by b and c = 15%, and that by c and
C150":
They were not feraiched by a pin; a knife marked them.
3 b. One
CHEMICAL ANALYSIS OF SOME CALAMINES. 79
6. One of thefe cryftals, expofed to the flame of the blow- Blowpipe ex
pipe, decrepitated and became opaque, and fhone witha green Ponments.
light, but feemed totally infufible. ;
Borax and microcofmic falt diffolved thefe cryftals, without
any effervefcence, producing clearcolourlefs glafles, Carbonate
of foda had little if any a€tion on them.
c. According to Mr. Pelletier’s experiments * on the cala-
mine of Fribourg in Brifgaw, which is undoubtedly of this
{pecies, its compofition is,
Quartz - - - - - 0.50
Calx of zinc - 2 = - 0.38
Water ~ 8 “ " « Owl?
1.00.
The experiments on the Regbania cryftals have had different
refults; but, though made on much fmaller quantities, they
will perhaps not be found, on repetition, lefs in conformity
with nature.
23.45 grs. heated red hot in a covered crucible, decrepitat-
ed a little, and became opaque, and loft 1.05 grs. but did not
fall to powder or grow friable. It was found, that this matter
was not in the leaft deprived of its eleétrical quality by being
ignited ; aad hence, while hot, the fragments of thefe decrepi-
tated cryftals clung together, and to the crucible.
d, 22.2 grs. of thefe decripitated cryftals, = 23.24 grs. of
the original cryftals, in a ftate of impalpable powder, being
digefted over a fpirit-lamp with diluted vitriolic acid, fhowed
no effervefcence ; and, after fome time, the mixture became a
jelly. Exhaled to drynefs, and ignited flightly, to expel the
fuperfluous vitriolic acid, the mafs weighed 37.5 grs.
On extraétion of the faline part by diftilled water, a fine
powder remained, which, after ignition, weighed 5.8 grs. and
was quartz.
The faline folution afforded, on cryftallization, only vitrio] Component
parts of eleétri«
of zinc. Thefe cryftals therefore confit of,
cal calamine.
Quartz - - - - 0.250
Calx of zinc - - = - 0.683
Water - - - - - 0.044
O77
Lofs “ - ~ - - 0.023
1.000.
* Journal de Phyfique. Tom. XX. p. 414,
The
80
It is found in
Derby thire.
Component
parts of fulphate
of zince
CHEMICAL ANALYSIS OF SOME CALAMINES.
The water is moft probably not an effential element of this
calamine, or in it in the ftate of, what is improperly called,
water of cryftallization, but rather exifts in the cryftals in fluid
drops interpofed between their plates, as it often is in cryftals
of nitre, of quartz, &c, Its fmall quantity, and the eryftals not
falling to powder on its expulfion, but retaining almoft per-
fetly their original folidity, and {pathofe appearance in the
places of fraéture, and, above all, preferving their eleétrical |
quality wholly unimpaired, which would hardly be the cafe
after the lofs of a real element of their conftitution, feem to
warrant this opinion.
If the water is only accidental in this calamine, its compofi-
tion, from the above experiments, will be,
Quartz. - - - - - 0.261
Calx of zine - - te 0.739
1.000
I have found this fpecies of calamine amongft the produc-
tions of Derbyfhire, in fmall brown cryftals, depofited, to-
gether with the foregoing {mall cryftals of carbonate of zinc,
on cryftals of carbonate of lime. Their form feems, as far as
their minutenefs and compreffion together would allow of
judging, nearly or quite the fame as that of thofe from Reg~
bania ; and the leaft atom of them immediately evinces its
nature, on being heated, by the ftrong eleétricity it acquires.
On their folution in acids, they leave quartz.
OBSERVATIONS.
Chemiftry is yet fo newa fcience, what we know of it bears
fo fall a proportion to what we are ignorant of, our know-
ledge in every department of it is fo incomplete, fo broken,
confifting fo entirely of ifolated points thinly fcattered like
lucid fpecks on a vaft field of darknefs, that no refearches can
be undertaken without producing fome faéts, leading to fome
confequences, which extend beyond the boundaries of their im-—
ete objeét.
. The foregoing experiments throw light on the proportions
in ee its elements exift in vitriol of zinc. 23.0 grs. of the
Mendip Hill calamine, produced 29.8 grs. of arid vitriol of
zinc. Thefe 23.0 grs. of calamine contained 14.9 grs. of
calx
CHEMICAL ANALYSIS OF SOME CALAMINES.» oD
ealk of zinc; hence, this metallic falt, in an arid ftate, con-
fifts of exaétly equal parts of calx of zinc and vitriolic acid.
This inference is corroborated by the refults of the other
experiments: 68.0 grs. of the Bleyberg calamine, containing
48.6 grs. of calx of zinc, yielded 96.7 grs. of arid vitriol of
zinc ; and, in another trial, 20.0 grs. of this ore, containing
14.2 grs. of calx of zinc, produced 28.7 grs. of arid vitriol of
zinc. The mean of thefe two cafes, is 62.7 grs. of arid vitriol
of zinc, from 31.4 grs. of calx of zinc.
In the experiment with the cryftals of carbonate of zinc from
Derbythire, 14.35 grs. of calx of zinc furnifhed indeed only
26.8 grs of arid vitriol of zinc; adeficiency of about ~$,5, occa-
fioned probably by fome fmall inaccuracy of manipulation.
2. When the fimplicity found in all thofe parts of nature Pofition that the
which are fufficiently known to difcover it is confidered, it “eve ciece
i p : pounds do not
appears improbable that the proximate conftituent parts of greatly exceed
bodies fhould be united in them, in the very remote relations to ach other in
each other in which analyfes generally indicate them ; and, an oo
attention to the fubjeét has led me to the opinion that fuch is
in faét not the cafe, but that, on the contrary, they are univer~
fally, as appears here with refpeét to arid vitriol of zinc, frac-
tions of the compound of very low denominators. Poflibly in
few cafes exceeding five.
The fuccefs which has appeared to attend fome attempts to
apply this theory, and amongft others, to the compofitions of
fome of the fubftances above analyfed, and efpecially to the
calamine from Bleyberg, induces me to venture to dwell here
a little on this fubje€t, and ftate the compofition of this cala-
mine, which refults from the fyftem, as, befides contributing
_ perhaps to throw fome light on the true nature of this ore, it
may be the means likewife of prefenting the theory under cir-
cumftances of agreement with experiment, which, from the
furprifing degree of nearnefs, and the trying complexity of the
_ cafe, may feem to entitle it to fome attention.
From this calamine, containing, according to the refults of Hence the com-
_ the experiments on the Mendip Hill kind, too {mall a quantity ee,
of carbonic acid to faturate the whole of the calx of zinc init, mine are fup-
and from its containing much too large a portion of water to es Geert
Th Saar ‘ ged in fubare
be in it in the ftate of mere moifture or dampnefs, it feems to dinate com-
confift of two matters; carbonic of zinc, and a peculiar com- Pounds.
_ pound of zinc and water, which may be named hydrate of
zinc.
Vor. VI.—Octoser, 1803. G By
Elucidations of
chemical theory.
CHEMICAL ANALYSIS OF SOME CALAMENES,
By the-refults of the analyfis of the Mendip-Hill calamine, »
corrected by thetheory, carbonate of zinc appears to confift of,
Carbonicacid - + - - & :
Calx of zinc mal), SNR ae
Deduéting from the calx of zinc in the Bleyberg calamine,
that portion which correfponds, on thefe principles, to its
yield of carbonic acid, the remaining quantity of calx of zinc
and water are in fuch proportions as to lead, from the theory,
to confider hydrate of zinc as compofed of
Calx of zinc - - ~ = 2
Water, or rather ice - e - z
And, from thefe refults, correéted by the theory, I confider
Bleyberg calamine as confifting of,
Carbonic of zinc = aes si attee
Hydrate of zinc © - - 3
: s
The teft of this hypothefis is in the quantities of the remote
elements which analyfis would obtain from a calamine thus
compofed,
The following table will fhow how very infignificantly the
calamine compounded by the theory, would differ in this ree
{peét from the calamine of nature.
1000 parts of the compound falt of carbonate and hydrate
of zinc confilt of, :
Carbonic 400
Carbonate of zinc} acid = ———-= ----- — 133%
400... = ‘~
Calx of 400 x 2
Zing = == 9662
= — 716}
Calx of 600% 3 ,
Hydrate of zinc zinc - = Hike, i hh
= 600 4-= - - 4 ’
600
Ice.) oss ae Ss ee - 156
4 Die ca
1000.
Great as is the agreement, between the quantities of the lat
column and thofe obtained by the analyfis of the Bleyberg ca-
famine, it would be yet more perfeét, probably, had there
been, in this inftance, no fources of fallacy but thofe attached j
to chemical operations, fuch as errors of weighing, wafte, &c,
but
3
CHEMICAL ANALYSIS OF SOME CALAMINESs
but the differences which exift are owing, in fome meafure
at leaft, to the admixture of carbonate of lime and carbonate
of lead, ih the calamine analyfed, and alfo to fome portion
of water, which is undoubtedly contained, in the ftate of
moifture, in fo porus and bibulous a body.
It has alfo appeared, in the experiments on the Mendip
Hill calarnine, that acids indicate a greater quantity of carbonic
acid than fire does, -225. If we make this deduétion for
diffolved water, it reduces the quantity of carbonic acid in the
Bleyberg calamine, to 0.1321.
If we affume this quantity of carbonic acid as the datum to
calculate, on this fyftem, the compofition of the calamine from
Bleyberg, we fhall obtain the following refults :
Compceund falt, of carbonate of zinc and hydrate of zinc 990.3
Water inthe ftate of moifture - - «© = 25
Carbonate of lime and carbonate of lead + 8 - WV 7
1000.0
It may be thought fome corroboration of the fyftem here
offered, that, if we admit the proportions which it indicates,
83
Elucidations of
chemical theorye
the remote elements of this ore, while they are regular parts .
of their immediate produéts, by whofe fubfequent union this
ore is engendered, are alfo regular fraétions of the ore itfelf:
thus, :
The carbonic acid - » - =e
The water a = = é =,
The calx of zine - ~ - me ES
Hereby difplaying that fort of regularity, in every point of
view of the objeét, which fo wonderfully charaéterifes the
works of nature, when beheld in their true light,
If this calamine does confift of carbonate of zinc and hydrate
of zinc, in the regular proportions above fuppofed, little doubt
can exift of its being a true chemical combination of thefe two
taatters, and not merely.a mechanical mixture of them ina
pulverulent ftate; and, if fo, we may indulge the hope of
fome day meeting with this ore in regular cryftals.
If the theory here advanced has any foundation in truth,
the difcovery will introduce a degree of rigorous accuracy and
certainty into chemiftry, of which this fcience was thought to
- be ever incapable, by enabling the chemift, like the geome-
trician, to re@tify by calculation the unavoidable errors of his
G2 manvwal
84 CHEMICAL ANALYSIS OF SOME-CALAMINES,
Elucidations of manual operations, and by authorifing him to eliminate from
chemical theorys the effential elements of a compound, thofe produéts of its
TEE
Se
analyfis whofe quantity caynot be reduced to any admiffible
proportion.
A certain knowledge of the exaé€t proportions of the con-
ftituent principles of bodies, may likewife open to our view
harmonious analogies between the conftitutions of related
objeéts, general laws, &c. which at prefent totally efcape us.
In fhort, if it is founded in truth, its enabling the application
of mathematics to chemiftry, cannot but be produétive of
material refults *
3. By the application of the foregoing theory to the experi-
ments on the eleétrical calamine, its elements will appear to
be,
Quartz - - - SM
Calx of zinc - - - - -
A {mall quantity of the calamine having (caged! the aétion
of the vitriolic acid, and remained undecompofed, will account
for the flight excefs in the weight of the quartz.
4, The exhalation of thefe calamines at the blowpipe, and
the flowers which they diffufe round them on the coal, are
probably not to be attributed to a direé volatilization of them,
It is more probable that they are the confequences of the dif-
oxidation of the zinc calx, by the coal and the inflammable
matter of the flame, its fublimation in a metallic ftate, and in-
ftantaneous recalcination. And this alternate reduction and
combuftion, may explain the peculiar phofphoric appearance
exhibited by calces of zine at the blowpipe. |
The apparent fublimation of the common flowers of zinc at
the inffant of their produé€tion, though totally unfublimable
afterwards, is certainly likewife but a deceptious appearance.
The reguline zinc, vaporifed by the heat, rifes ‘from the
crucible as a metallic gas, and is, while in this ftate, convert-
ed toacalx. The flame which attends the procefs is a proof
of it; for flame is a mafs of vapour, ignited by the produétion
of fire within itfelf. The fibrous form of the flowers of zinc,
is owing toa oo of the calx while in mechanical f~
ple pls
* It may be pr oper to fay, that the experiments have been ftated
precifely as they turned out, and have not been in the Jeafl degree
bent to the fyftem.
penfion
CHEMICAL ANALYSIS OF SOME CALAMINES. 85
penfion in the air like that which takes place with camphor’ Elucidations of
when, after having been fome time inflamed, it is blown out. chemical theorys
A moment’s refleGtion muft evince, how injudicious is the
common opinion, of cryftallization requiring a ftate of folution
in the matter ; fince it muft be evident, that while folution fub-
fifts, as long asa quantity of fluid admitting of it is prefent, no
cryftallization can take place. The only requifite for this opera-
tion, is a freedom of motion in the maffes which tend to unite,
which allows them to yield to the impulfe which propels them
together, and to obey that fort of polarity which occafions
them to prefent toeach other the parts adapted to mutual union.
No fiate fo completely affords thefe conditions as that of me-
chanical fufpenfion in a fluid whofe denfity is fo great, rela-
tively to their fize, as to oppofe fuch refiftance to their defcent
in it as to occafion their mutual attraction to become a power
fuperior to their force of gravitation. It is in thefe circumftances
that the atoms of matters find themfelves, when, on the fepa-
ration from them of the portion of fluid by which they were
diffolved, they are abandoned in a difengaged ftate in the
bofom of a folution; and hence it isin faturated folutions fuf-
taining evaporation, or equivalent cooling, and free from
any perturbing motion, that regular cryftallization is ufaally
effefted. ;
But thofe who are familiar with chemical operations, know
the fort of agglutination which happens between the particles
of fubfided very fine precipitates: occafioning them, on a
fecond diffufion through the fluid, to fettle again much more
quickly than before, and which is certainly a cryftallization,
but under circumftances very unfavourable to its perfeét per-
formance.
5. No calamine has yet occurred to me which was a real,
uncombined, calx of zinc. Iffuch, as a native produé, fhould
ever_be met with in any of the ftill unexplored parts of the
earth, or exift amongft the unfcrutinized poffeffions of any
cabinet, it will eafily be known, by producing a quantity of arid
vitriol of zinc exa@ly double its own weight; while the hydrate
of zinc, fhould it be found fingle, or uncombined with the car-
bonate, will yield, it is evident, 1.5 its weight of this arid falt.
TABLE
86 RADII, OF WHEELS.
VI.
Table of the Radii of Wheels, from Ten to Three Hundred Te eeth,:
the Pitch* being Tuo Inches. By Mr. B. Donxin,
Millwright, Dartford, Kent t.
Table of the
sages ti No. | Radius i
radii of wheels of ih No. | Radius. No. | Radius.
Teeth} Inches.
10 3,236 42}. 13,382. _ TA | 23,562
1] 3,549 43 | 13,700 75 | 23,880
12| 3,864 44} 14,018 76 | 24,198
13 | 4,179 45 | 14,336 77 | 24,517
14] 4,494 46] 14,654 78 | 24,835
15 4,810 47 | 14,972 79.\) 25,153
16 | 5,126 48 | 15,290 80 | 25,471
17 | ° 5,442 49 | 15,608 81 | 25,790
18 5,759 50 | 15,926 82 | 26,108
19 | 6,076 51} 16,244 83 | 26,426
20 | 6,392 521 16,562 84 | 26,744
21 6,710 53 | 16,880 85 | 27,063
Pood Bul27, 54 | 17,198 86 | 27,381
93 | 7,344 55.4 by yo he 87 | 27,699
24 | 7,661 56 | 17,835 88 | 28,017
25 7,979 57d: 18,053 89 | 28,336
26 8,296 58 | 18,471 90 | 28,654
27 | 8,614 59 | 18,789 91 | 28,972
28 8,931 60 | 19,107 92 | 29,290
29 | 9,249 61 | 19,425 93 | 29,608
30 | 9,567 62 | .19,744 94 | 29,927
31 | 9,885 | 63 | 20,062 95 | 30,245
32 | 10,202 64 | 20,380 96.| 30,563 }
33 | 10,520 65 | 20,698 97 | 30,881 |
34 | 10,838 66 | 21,016 98 | 31,200
35 | 11,156 67 | 21,335 99 | 31,518
36 | 11,474 68 | 21,653 100 |- 31,836
37 "| 11,792 69 | 21,971 — F101 | 32;155
38 | 12,110 70 | 22,289 102 | 32,473
39 | 12,428 71 | 22,607 103 | 32,791
40 | 12,746 72 | 22,926 104 | 33,109
4} 13,064 73 | 23,244 105 | 33,427
op eS ge a ee 5 ea
* By the pitch is underftood the diftance between the centers of
two Contiguous teeth; and by the radius is underftood the diftance
between the center of the wheel and the center of each tooth.
t Communicated by the author.
: . No
Radius.
34,064
345382
34,700
35,018
OIF aT
35,655
35,974
536,292
36,929
37,247
37,565
37,883
38,202
38,520
38,838
39,156
- 39,475
39,793
40,111
40,429
40,748
41,066
41,384
41,703
| 42,021
42,539
42,657
42,976
43,294
43,612
43,931
44,249
44,567
44,885
45,204
45,522
45,840
46,158
46,477
46,795
47,113
47,432
47,750
| 33,746
36,6) 1.
RADIL OF WHEELS.
Radius.
48,068
48,387
48,705
49,023
49,341
4.9,660
49,978
50,296
50,615
50,933
51,251
51,569
51,888
52,206
52,524
52,843
53,161
53,479
53,798
54,116
54,434
54,752
55,071
55,389
55,707
56,026
56,344
56,662
56,980
57,299
57,617
57,935
58,253
58,572
58,890
59,209
59,527
59,845
60,163
60,482
60,800
61,118
61,436
61,755
62,073
Radi us,
62,392
62,710
63,028 .
63,346
63,665
63,983
64,301
64,620
64,938
65,256
65,57 4
65,893
66,211
66,529
66,848
67,166
67,484
67,803
68,1211
68,439
68,757 '
69,075
69,394
69,712
70,031
70,349 °
70,667
70,985 —
71,304
71,622
71,941
72,258
72,577
72,395
73,214
73,532
73,850
74,168
74,487
74,805
75,123
75,441
75,760
76,078
16,397
87
Table of the
radii of wheels,
88
Table of the
radii of wheels.
-_
RADII OF WHEELS.
Nc
No. Radius, No. Radius. No. Radius.
241 | 76,715 261 | $3,081 281 | 89,447
242 | 77,033 262 | 83,399 | -| 282] 89,765
243 | 77,351 263 | 83,717 283 | 90,084
244 | 77,670 264 | 84,036 284 | 90,402
245 | 77,988 265 | 84,354 285 | 90,720
246 | 78,306 266 | 84,673 | ’ | 286 | 915038
247 | 78,625 267 | 84,991 287 | 91,357
248 | 78,943 268 | $5,309 288 | 91,675
249 | 79,261 269 | 85,627 289 | 91,993
250 | 79,580 270 | 85,946 290 | 92,312
251 | 79,898 271 | 86,264 291 | 92,630
252 | 80,216 272 | 86,582 292 | 92,948
253 | 80,534 273 | 86,900 293 | 93,267
254 | 80,853 274| 87,219 294 | 93,585
255 | 81,171 275 | 87,537 255 | 93,903
256 | 81,489 276 | 87,855 | 296 | 94,229
257 | 81,808 277 | 88,174 297 | 94,540
258 | 82,126 278 | 88,492 298 | 94,858
259 | 82,444 279 | 88,810 299 | 95,177
260 | 82,763 280 | 89,129 300 | 95,495 |
N. B. When the pitch is different from two inches, the
radius of a wheel of any number of teeth, from 10 to 300 may
be found from this table, by the Rule of Three; for as two
inches (the pitch in the table) is to any radius in the table, fo
is any given pitch to the radius required.
For Example ; let it be required to find the radius of a wheel
of 100 teeth, when the pitch is 1} inches. The radius of a
wheel of 100 teeth is, in the table, 31,836 inches. Accord-
ingly we have 2 : 31,836 : : 1,25, to the number of inches in
the radius required ; which will be found 19,897 as by the
Operation annexed.
2 B1;836-09 1,25
1525
159180
| 63672
31836
2) 39,79500
19,8975
‘
VII. Account n
PYROMETER OF PLATINAs 89
sind Ate
Account of the Pyrometer of Platina. By Citizen GuyTon.*
Cinzen GUYTON prefented an inftrument to the irieken ail for
ting of the French National Inftitute of the 26th Floreal laft, Gifting of pecranik
intended to meafure the highéft degrees of heat of our furnaces. of platina moved
It confifts of a rod or plate of platina placed horizontally in i ish
a groove formed in a cake of hardened white clay. This plate fame metal; the
is fupported at one of its extremities on the part of the mafs vont ing. 10
which terminates. the groove; the other end preffes againft a ce baked clay.
bended lever, whofe longeft arm forms an index toa graduated sl is resin by
arc; fo that the change of poiition of this index indicates the ie Bei |
expanfion produced on the plate of metal by the heat. pottery and pla
The cake of clay having been highly baked, leaves no caufe Defeription.
to apprehend any contraction; and the expanfion which may
take place during the ignition will only affeét the very fmall
diftance between the axis of motion of the index and the point
of contaét of the plate, that is to fay, in fuch a manner as ra-
ther to diminith the effeé& than to increafe it.
All the parts of this inftrament being of platina, neither fu-
fion nor oxidation are to be apprehended.
With refpe& to its dimenfions, the author conceives that in Dimenfions.
order to render the ufe of it commodious and accurate, they
' fhould be reduced to fuch as may be neceffary to obtain fenfible
variations ; it will then be rendered commodious by the facility
with which it may be placed under a muffle or an inverted
erucible, &c. and accurate, becaufe the probabilities of any
accidental inequalities of the heat will be diminifhed, which it
is impoffible to avoid to a certain extent, even in the midft of
a large mafs of fire. :
The variations will be fafficiently perceptible, if we can not Degree of accu-
only eftimate, but correétly determine expanfions of the 200th ™°Y:
part of a millimetre (about the 5000th part of an inch,) thefe
the author obtains by the proportions of the inftrument which
he has himfelf adopted.
The rod or plate of expanfion is 45 millimetres (one inch Dimenfions of
and three quarters) in‘length, 5 in width (one fifth of an inch) "© Parts.
and 2 in thicknefs (one thirteenth of an inch.)
* Annales de Chimie, No. 138. XLVI. 276.
The
90 PYROMETER OF PLATINA.
The arm of the bended lever, which prefies againft the end
of this rod, is 25 millimetres in length; (rather 24, or about
one ninth of aninch) and the arm at right angles to it, or the
index, which traverfes on the graduated arc, is 50 millimetres
in length (one inch and eight tenths) or twenty times the length
of the other. The fpace traverfed by the difplacing of the ©
fmall arm will be thus encreafed in the proportion of t to 20.
As the long arm or index carries a nonius which divides
each degree on the graduated arc into ien parts, we can dif-
tin@tly obferve the 200th of one of thofe meafures (referred to
the bar itfelf.) ,
Laftly, As the decimal divifion of an are of a circle of 50
millimetres radius, gives only 7.8538 deci-millimetres for one
of its degrees, it is evident then that we may meafure an ex-
panfion of 0.078538 deci-millimetres, or of the 5730th part
of the length of the radius.
In order to prevent the pofition of the index from being .
changed in removing the inftrument from the furnace, a plate
of platina is fixed fo as to form a fpring againft its extremity.
The author has commenced a feries of éxperiments to de-
termine the range of this pyrometer, to compare.it-with the
pyrometric pieces of Wedgewood, and fo to fhew the degree
of confidence it merits, the methods of ufing, and the cafes
in which it may be ufefully employed in philofophical refearches
and in the arts.
—a
Vil.
Lester from Mr. Ezekiel Walker on the Proportion of Light
afforded by Candles of different Dimenfions.
To Mr. NICHOLSON,
SIR,
Obfervations on Your correfpondent, who has made fome remarks on my
be iy tothe experiments on candles, does not feem to have fufficiently
confidered his fubjeét; for had he paid attention to my paper
on page 40 of the fourth volume of your Journal, he could not
have advanced that ‘ Though Mr. Walker afferts with con-
fiderable decifion, that the light afforded by candles, is pro-
portioned to the quantity of material confumed, yet he has not
given
PROPORTION OF LIGHT AFFORDED. BY CANDLES. Ol
given the detail of his experiments, but feems in fome mea-
fure to have difcovered this refult by argument, from the fup-
pofed nature of the fubjeé.” *
In the table in my paper above mentioned, the laft cobain Obfervations of
contains the diftances of the candles from the wall, when the i oy
fhadows were equal; and the fourth column contains the the weights cone
weights of thofe candles confumed ina given time, and thefe aanee
are all the data required for making the calculations, to fhow
whether my deduction is true or falfe. The mode of calcu-
lating feemed to me, at the time I wrote that paper, too eafy
to need any illuftration, but as I now ftand charged by your
correfpondent, of having deduced a general law from doubtful
principles, a further explanation becomes neceffary.
To inveftigate rules for this purpofe, 1. Let M reprefent the Inveftigation of
mould Bandle, a its diftance from the wall, on which the fha- at ae val
dows were compared, x its quantity of matter confumed ina re
given time, (¢) and Q the quantity of light emitted by M in
the fame time: 2. Let m reprefent any other candle, b its dif-
‘tance from the fame wall, and y its quantity of matter con-
fumed, in the time ¢.
Then as the intenfities of light are direéily as the fquares of
the diftances of the two candles from the wall, we have, as
2
~a*:Q:: db: axes the quantity of light, emitted by
m inthe time, |
_ Then let us fuppofe that the quantities of light are direétly
as the quantities of matter confumed in the time ¢, and we
eaves; As 2 > Qs: y 3 —_ = the quantity of light
emitted by m in fe time, by hypothefis.
ee
Now, when —— (ied...) is: = = ~ = (Theo. 2.)
the quantities of light of M and m are dire as their quan-
. tities of matter dawhithied in any given time,
By thefe rules, the calculations contained in the following
table, were made from the experiments mentioned at the be-
ginning of this paper.
* See Philofophical Journal, Vou, V. page 219%
CY PROPORTION OF LIGHT AFFORDED BY CANDLES,
Light | Light | 2dRule
by | by (differsfrom
Rule I. |Rule 1]. | the rf.
No of ex-
periments.
1 {No. 1. compd. with the mould | 1.000} 1.000} .000
2 |No. 1. compd. with do. 1.000 | 1.000 .000
3 |No.1.compd. with do, 1.000 {1.015 | + .015
3 |No. 3. compd. with do. 1,196 | 1.125 | — .07]
4 |No, 4. compd, with do. 1,196 | 1.226 | + .030
The mean error of the 2d Rule — .005
As the mean refult given by the 2d rule, differs only 1 in 200
from the 1{t, which is univerfally received as true, the 2d rule
appears fufficiently exaét for many praétical purpofes, where
the properties of that light is concerned, which is produced
by candles,
EZEKIEL WALKER.
Lynn Regis, 20th Sept. 1803.
Whether the P. 8S. As to your correfpondent’s experiment, it does not
experiments of a annear fo correét to me, as it appears to himfelf; for every one
correfpondent be : a
eccurate, knows, that one end of a mould candle is thicker than the other,
therefore if that gentleman made his experiment with the {mall
end of his candle, he has eftimated the quantity of light pro-
duced by a pound, too little; and if he made his experiment
with the large end, his eftimation is too great; and moreover,
it may be doubted, whether the 4, part of a pound of candles,
can be fo exaétly afcertained by meafuring as by weighing,
even if the candles were perfeét cylnders.
a
IX.
On the Compounds of Sulphur and Ovygen. By Tuomas —
‘Tuomson, M. D. Leéturer on-Chemiftry in Eien From
the Author.
Three known if
compounds of Tis at prefent the opinion of Chemifts that fulphur is capa-
cra sagetienortmggl combining with three dofes of oxygen, and of forming —
ygen, 1. oxide,
2. acids. three diftinét compounds, namely,
1.,Oxide of Sulphur.
2 Sulphurous Acid.
3. Sulphuric Acid. i
The
ON THE COMPOUNDS OF SULPHUR AND OXYGEN. , 93
The firft of thefe is fuppofed to contain a minimum, the third
’ amaximum of oxygen. “Of thefe three the conftituents of
the laft only have been afcertained with precifion. It will be
proper to begin with it, as the knowledge of its compofition
_ may be of fervice in afcertaining the conftituents of the reft.
I. Of Sulphuric Acid.
This acid has been lately analyfed with precifion by Sulphuric acid,
Thenard and Chenevix. I have repeated their experiments a vaete (ee
with care, and have obtained for the mean refult 39 per cent. oxygen.
of oxygen, which is only one half per cent. greater than the
refult obtained by Mr. Chenevix. This difference in the pre-
fent ftate of analyfis may be accounted altogether infignificant.
I fhall confider fulphuric acid, then, as compofed of F
61 fulphur
39 oxygen
100
II. Of Sulphurous Acid.
Moft of the properties of this Acid have been long known Sulphurous acid.
_tochemifts; but no experiments have been made to afcertain
the proportion of its component parts. Before I proceed to
relate the refult of mine, it may be worth while to defcribe a
few of the properties of Sulphurous Acid, which have not hi-
| therto been ftated with precifion. ¢
1. Fifty-three meafures of fulphurous acid gas were intro- Water at 60° ab-
duced into'a graduated tube ftanding over mercury, and one Reged
meafure of water was thrown up. In five minutes 20 mea-its piehtoe Ol.
fures of gas were abforbed, and in 24 hours the abforption Phurous canuP
amounted to 33 meafures. No farther abforption took place
in three days more ;_ but on introducing the tube into water,
the whole gas difappeared, except a {mall globule, which did
not exceed 1-10th ofa meafure. During this experiment the
thermometer at the time of obfervation deviated very little
from 61°, and the barometer ofcillated from 29.55 to 29.77.
Water then, at the temperature of 61°, abforbs 33 times its
bulk of this gas. Now, if with Lavofier, we fuppofe a cubic
inch of gas to weigh 0.63 grs. a cubic inch of water will ab-
forb 19.79 grains of fulphurous acid, and ¢° parts of water
will abforb 8.21 parts by weight.
"2, A current
Od ON THE COMPOUNDS OF SULPHUR AND OXYGEN.
The impregnat- 2. A current of fulphurous acid gas was paffed through a
nate 5 Sy large quantity of water till the liquid refufed to abforb any
gratity ve pas more. The'tafte of the water thus faturated, was{intenfely
ci a acid and fulphureous, and its odour exceflively ftrong. The
Sere aot fpeenie gravity at the temperature 68° was 1.0513; the heat
of the hand was fufficient to occafion an extrication of gas.
Whien moderately heated, it frothed violently, and exhaled
the denfe blue f{moke which ufually indicates the prefence of
fulphurous acid. When boiled down in a retort to half its
bulk, it loft its fmell, but ftill continued ri ap acid. Hence
it obvioufly contained fulphuric acid.
Analyfis of ful- - 3. In analyfing the different fulphites, I have not found
Pate barytes an{wer fo well as I was led to expeét from the experi-
phurous acid ments of Fourcroy and Vauquelin; the folubility of fulphite.
paras oF iia of barytes in water is fo confiderable, that precifion by means
phuric acid. of it is fcarcely to be looked for. But nitrate of lead yields’
with the alkaline and earthy fulphites a white infoluble powder
of fulphite of lead, which may be dried in the temperature of
800° without decompofition, and is then compofed of about
25 fulphurouws acid.
‘a 75 yellow oxide of lead.
100
One hundred parts of the above liquid fulphurows acid
yielded, with nitrate of lead, a precipitate indicating the pre--
fence of 6.15 parts of fulphurous acid. Another hundred
parts, boiled down to one half in a retort, yielded, with muriate
of barytes, a precipitate indicating the prefence of 0.34 ful-..
phuric acid. Therefore, 100 parts of my liquid fulphurous
acid contained about
5.81 fulphurous acid,
0.34 fulphuric acid,
6.15.
So that the fulphuric acid amounts nearly to 4 of the ful-
phurous. The prefence of this acid is a proof of an affinity
between fulphurous acid gas and fulphuric acid ; for the gas.
was pafled through an intermediate veffel before it reached
the water.
This contamina~ 4, The proportion of\ acid combined with water in the li-
ae ga nase quid fulphurous aaid was rather lefs than 7 ; yet, when water
lefs capable of js plunged into a large column of gas, we have feen that it
abforbing ful- abforbs:
_phurous gas.
ON THE COMPOUNDS OF SULPHUR AND OXYGEN, 95
abforbs rather more than eight parts of it by weight. Perhaps
this difference was owing to the prefence of the fulphuric acid
in the liquid. For water, flightly acidulated with fulphuric
acid, abforbs a {maller proportion of gas, than pure water.
5. After trying various experiments, in order to afcertain Analyfis of fuls
the conftituents of fulphurous acid, I found the following Phurous acid,
method moft to be depended on.
Sulphite of potafh was obtained by Berthollet’s method. Sulphite of pote
It isa fine white falt, the properties of which have been Pe gtr by aiiee
fully detailed by Fourcroy and Vauquelin, though they haveheat: by igni-
negleéted to analy(e it. tion it lofes 22.3,
5 f % é _and fulphuric
When this falt is expofed for a few minutes to a heat ofacid with the ale
300°, it lofes 3.3 per cent. of its weight; and fuffers no ad-ali areleft.
ditional lofs, though the heat be continued for an ‘hour.
When heated to rednefs in a platinum crucible, it decrepi-
tates, becomes of an opake white, a blue flame iffues from
below the lid, and, on taking off the cover at that inftant,
the falt may be obferved of a glowing red heat in the middle.
When this glow difappears, tie falt willbe found to have fuf-
tained a lofs of 22.3. per cent. and it lofes no more, though
melted, and kept half an hour in fufion. On evolving, it fplits
_ into the fine thin tranfparent plates, which diftinguih fulphate of
potath in the fame circumftances. When this refidue is dif-
-folved in water, and treated with muriate of barytes, this
q precipitate of fulphate of barytes obtained, when dried and
heated to rednefs, weighs 95.5, indicating the prefence of
22,92 fulphuric acid, Suppofing with M. Chenevix, that
_ fulphate of barytes contains 24 per cent. of fulphuric acid 3
_ hence it follows that fulphate of potath is compofed of
22.30 volatile matter
22.25 fulphuric acid
55.45 potafh
ed
100.00
When 100 grains of fulphate of potath were expofed to the The volatile
heat of a lamp in a retort with a very long beak, fitted to a tis fulphu-
rous gas, with
© mercurial air holder, they decrepitated and affumed the ap-fome fulphur
"pearance of an opake white powder: 18 cubic inches of gas pee hae Wee
were extricated, and fulphur, with a little water, was volati-
4 lized into the beak of the retort; the gas was abforbed by
| water, and had the ufual {mell of fulphurous acid: the retort
had
96
Component parts
of fulphite of
potafh.
Explanation of
the aétion of
heat on fulphite
of potafh.
ON THE COMPOUNDS OF SULPHUR AND OXYGEN.
had loft 15.2 grains of weight. The fulphur being carefully
colleéted, was found to weigh 5.1 grains. When burnt, it
left 0.1 of refiduum, which feemed to be fulphurate of iron,
for it gave a yellow colour to muriatic acid ;* the water vola-.
tilized could not be weighed, but I eftimate it at 2 grains.
The experiment fhews us what the volatile matter is which is
drawn off when fulphate of potafh is heated to rednefs. It is
compofed of 15.2 fulphurous acid
5.1 fulpbur
2.0 water
2250
The falt which remained in the retort being diffolved, and |
treated with muriate of barytes, gave a precipitate which in-
dicated the prefence of 23.2 of fulphuric acid. Hence ful-
phate of potath is compofed of —
23.2 fulphuric acid
15.2 fulphurous acid
5.1 fulphur
54.5 potahh
2.0 water
100.0
But it is obvious that, before the application of heat, the
firft three conftituents together conftituted fulphurous acid.
Hence fulphite of potath is compofed of
43.5 fulphurous acid
54.5 potafh
: 2.0 water
100.0
This analyfis enables us to trace the changes produced upon
fulphite of potafh by heat. A temperature of 300° feparates
the water and a {mall portion of fulphurous acid, which
feems more loofely combined; for the falt, in confequence,
lofes its fmell; an increafe of heat occafions a feparation of
a portion of the acid, unaltered ; the remainder divides itfelf
into two parts, namely, fulphuric acid, which remains com-
bined with the potafh, and fulphur, which fublimes. Hence
* I have never yet burned fulphur, without obferving traces of a
fimilar refiduum.
4 we
|
:
ON THE COMPOUNDS OF SULPHUR AND OXYGEN. 97
we learn, that fulphurous acid is compofed of 23.2 fulphuric
acid, and 5.1 fulphur, which gives us
82 fulphuric acid
18 fulphur ‘
100
But 100 parts of fulphuric acid contain 39 of oxygen; there-
fore 82 contain nearly 32, Hence fulphurous acid is com-
pofed of 68 fulphur
32 oxygen
- 100
Fourcroy affirms, that fulphurous acid contains only about 15
per cent. of oxygen, which is lefs than one half of the refult
juft given. But he quotes no experiment in proof of his affer-
tion. Inall probability it was a mere guefs.
6. The phenomena which attend the acidification of ful-Sulphurous acid
phur and the decompofition of falphurous acid, render it pro ee ee
bable that fulphurous acid is rather a compound of fulphuriced with fulphue
acid and fulphur, than of fulphur and oxygen. ribet
Sulphur and fulphuric acid combine with great facility.
For if we form them into a probe, a very tne tleses heat is
fufficient to convert the whole into fulphurous acid gas.
Whenever fulphur is acidified, a portion of fulphuric acid
always makes its appearance in whatever way the procefs is
conduéted. Such at leaft has been the conftant refult of my
experiments,
When fulphur is expofed to the heat of an Argand lamp
_ in aretort conneéted with a mercurial air holder, it melts and
fublimes at firft rapidly, but much more flowly, when the pro-
cefs has continued for fome time. Ina retort, whofe capa
city was 63 cubic inches, four hours elapfed before 3 oz, of
fulphur was fublimed into its neck. A confiderable quantity
of air was driven over; but on allowing the veffels to cool,
the whole returned again, except 3 cubic inches. So that,
by ‘the operation, the air in the retort had increafed about
gothpart. It fmelt very pungently of fulphurous acid. When
agitated in water, a {mall portion of it difappeared. The
_ water did not acquire a perceptible tafte, but it precipitated
Muriate of barytes even after being boiled for fome time. A
portion of this air, after being well wafhed, was left in con-
_ taét with a flick of phofphorus over water. Its bulk was di-
Vor. VIL—Ocroser, 1803. H minifhed
O§ ON THE COMPOUNDS OF SULPHUR AND OXYGEN.
minifhed 17 percent. Hence it had loft 5 per cent. of oxy-
gen by the aétion of the hot fulphur on it. Here we fee the
fource of the acidification of the fulphur during its fublimation.
From this experiment we are authorized to conclude that both
fulphuric and fulphurous acids may be formed merely by
heating fulphur in comimon air, without any fenfible com-
buftion.
Sulphur, when- Sulphuric acid feems to be formed whenever fulphur is
a nary aaa fublimed. For every fpecimen of flowers of fulphur which I
have had an opportunity of examining, contained that acid.
If common flowers of fulphur be boiled in water, the li-
quid always precipilates muriate of barytes. But flowers of
fulphur, when once they have been well wafhed and dried,
communicate no fuch property to water. If we now fublime
thefe very flowers a fecond time, water in which they are
boiled, precipitates muriate of barytes, as at firit.
Combutition of —§ Whena red hot glafs capfule is rapidly placed ona pedeftal of
fulphur under 2 fonding water fulphur thrown into it, and a glafs jar fuddenly
gar over water. te) y, oe 5 /
put over it, the combuftion of the {ulphur continues for a con-
fiderable time ; denfe bluifh-white fumes fill the jar, and at
laft conceal the flame completely. The fmoke foon fubfides
when the combuftion is over, and the water rifes flowly in the
jar. . By this procefs, the air in the jar lofes.uniformly 8 per
cent. of oxygen; it retains the fmell of fulphurous acid, even
though allowed to remain over water for a week. But the
fmell difappears in an inflant, if the air be paffed through water.
A portion of the water over which the jar ftood, being treat-
ed with muriate of barytes, yielded a precipitate which
weighed 8. An equal portion of the fame water evaporated
to one-fourth, yielded a precipitate which weighed 7.
A@ion of acids 7, The ation of the more powerful acids upon the ful-
on the fulphitess Shites deferves attention, becaufe it ferves to illuftrate the na-
ture of fulphurous acid. ‘This aétion has been defcribed with
confiderable minutenefs by Fourcroy and Vauquelin ; but as
the refult of my experiments differs a little from theirs, a few
obfervations may not be unacceptable to the chemical reader,
Yo prevent tedioufnefs, I fhall confine my remarks to fulphite
of potath,
Aétion of ful- | When fulphite of potafh is thrown into concentrated ful-
bikie al ed phuric acid, a confiderable heat is evolved, a violent effer-
ath. velcence takes place, and the falt lofes 48 per cent. of ils
4 weight.
ON THE COMPOUNDS OF SULPHUR AND OXYGEN,
weight. The heat of boiling water renews the effervefcence,
_ and occafions a lofs of weight, amounting to 2 per cent. more.
So that fulphite of potafh, when treated with fulphuric acid,
lofes uniformly the half of its weight. Yet it contains only
43.5 per cent. of fulphurous acid. The additional 6.5 parts
may be afcribed perhaps to the efcape of fulphuric acid along
with the gas ; for it can fcarcely be doubted that there is an
affinity between them, When the fulphuric acid folution is fet
afide, brilliant plates of fuper-fulphate of potafh foon make
their appearance in it.
~ When fulphite of potafh is thrown into muriatic acid, a
violent effervefcence enfues, but no increafe of temperature ;
and the falt lofes 34 per cent. ofits weight. The heat of boil-
ing water renews the effervefcence, and occafions a farther
lofs of 16 per cent. making the whole lofs amount to 50, as
in fulphuric acid. From this experiment we fee that muriatic
acid does not expel the whole of fulphurous acid, unlefs affift-
ed by heat: and inthat cafe, a portion of the muriatic acid is
driven off at the fame time with the fulphurous. When the
muriatic acid folution is fet afide, beautiful arborefcent cry{-
tals of muriate of potafh make their appearance in it.
Muriatic acid
and fulphite of
aih.
I diffolved 500 parts of fulphite of potafh in water, and Oxy muziatic
putting the folution in a Woulfe’s bottle, caufed a current of
oxy muriatic acid gas to pals through it ; the gas paffed after-
wards through a fecond bottle of water conneéted to the firft
by a bent glafs tube. After the procefs the bottles were fet
' afide, till the green colour, occafioned by the oxy-muriatic
acid, difappeared, and the fetid animal odour which ufually
fucceeds that colour, was become perceptible. From the
firft bottle I obtained, by means of muriate of barytes, a pre-
cipitate whch weighed 777 parts, indicating the prefence of
37.3 per cent. of fulphuric acid. Butas the fulphurous acid
originally prefent amounted to 43.5 per cent. had it been
wholly converted into fulphuric acid, not lefs than 48.5 per
cent. of fulphuric acid would have been obtained, there was
a lofs then of 11.2 per cent. of courfe, 10.5 parts of fulphurous
acid muft have been diffipated by the aétion of the oxy mu-
riatic acid. Accordingly the liquid in the fecond phial gave
an abundant precipitate with muriate of barytes: and this
“8 contrary to what I expected, confifted chiefly of
H 2 {ulphite
gas and fulphite
of potafhe
100
ON THE COMPOUNDS OF SULPHUR AND OXYGEN.
fulphite of barytes; for the greater part of it was foluble in
fulphurous acid.
Nitric acid and When fulphite of potafh is thrown into concentrated nitric
fulphite of pot-
ath.
Compofition of
fulphite of pot-
afh.
acid, a violent effervefcence takes place, and much heat is
evolved, the lofs of weight is 44.5; the liquid treated with
nitrate of barytes, gives a precipitate, which indicates the pre-
fence of 39.6 of fulphuric acid. Hence we fee that the lofs
of weight during the effervefcence was owing chiefly to the
efcape of nitrous gas.
When the acid is diluted, the effervefcence is violent, but
no heat is evolved, and the {mell of fulphurous acid gas mak-
ing its efcape is very perceptible. The lofs of weight is only |
12 per cent. the refiduum, treated with nitrate of barytes, gave
a precipitate indicating the prefence of 43.2 per cent. of ful-
phuric acid. Here we fee that moft of the lofs of weight was
owing to the efcape of fulphurous acid: yet the greater part
was converted into fulphuric acid.
8. During the courfe of thefe experiments I had occafion to
examine the compofition of fulphate of potafh ; and as my re-
fults differ a little from thofe ftated by others, it will be pro-
per to notice fome of them in this place,
When fulphite of potafh is heated to rednefs in a pla-
tinum crucible, the refiduum pofleffes the properties of fulphate
of potafh.. It may be fufed without any lofs of weight, and
when diffolved and cryftallized again, we obtain the fame falt
as at firft: 100 parts of this falt precipitated by muriate of ~
barytes, yields a precipitate which, after being heated to red-
nefs, weighs, at a medium, 96 parts, indicating about 23 per
cent. of fulphuric acid. Hence this fulphate is compofed of
23 acid
67 potafh
100
When fulphuric acid is fuperfaturated by means of carbonate
of potafh, we obtain by evaporation the common fulphate of
potath of chemifts: the fame falt feparates in cryftals during
the purification of the potafh of commerce. When the falt is
reddened in a platinum crucible, it lofes 1.4 per cent. of its
weight, and no more, though it be kept in fufion. Diffolved
in water, and treated with muriate of barytes, it yields a pre-
cipitate which weighs 128.5 ; the mean of three experiments
differing
Pid
ON THE COMPOUNDS OF SULPHUR AND OXYGEN, JO]
differing from each other not more than 3.5 per cent.*
Hence it contains 30,84 fulphuric aehd, This fulphate, then,
is compofed of
30.84 acid
67.76 potath
1.40 water
100.00
When fulphite of potath is left for fome months expofed to
the air, and then heated to rednefs, it yields with muriate of
barytes a precipitate indicating about 38 per cent. of ful-
phuric acid.
The fuperfulphate of potath lofes 26 per cent. ina red
heat, and the remaining 74 parts diffolved in water, and
treated with muriate of barytes, yield a precipitate indicating
the prefence of 30.4 {ulphuric acid, whereas 100 parts of the
fuperfulphate diffolved in water, without being previoufly
heated, yield, with muriate of barytes, a precipitate indicat-
ing the prefence of 38.4 fulpburic acid. Hence it follows
that the falt is compofed of
38.4 acid
43.6 alkali
18.0 water
100.0;
or, abftraéting the water, of 46.4 acid °
53.6 alkali
100.0
III. Oxide of Sulphur.
Sulphur ufuafly occurs in one or other of three ftates ; External charace
namely, 1. A whitifh powder, formerly diftinguiflied by the ters of fulphur.
name of lac fulphuris. 2. In rolls or flowers of a greenifh
yellow colour. This‘is the fulphur of commerce.. 3. In the
ftate of a reddifh yellow, pitchy fubftance. This is commonly
employed for forming the cafts of medals, &c. known by the
name of fulphurs.
* Mr. Vauquelin affirms, in his Differtation on the Potath of
Commerce, that this falt yields with muriate of barytes a precipi-
tate amounting to 22°, the weight of the falt. My experiment
differs very much from this ftatement.
tee
~
102 ON THE COMPOUNDS OF SULPHUR AND OXYGEN.
Lac fulpburis, or 1 It is well known that fulphur, when firft obtained by
white fulphor, is precipitation from any liquid, is always of a white colour,
a Slow fal, Which gradually changes to greenifh yellow when the ful-
phur is the pure. phur is expofed to the open air. If this white powder, or lac
Sulphuris, as it is called, be expofed to a low heat in a retort,
it foon acquires the colour of common fulphur ; and, at the
fame time, a quantity of water is depofited in the beak of the
retort. On the other hand, when a little water is dropt into
melted fulphur, the portion in contaét with the water imme-
diately affumes the white colour of lac fulphuris. If common
fulphur be fublimed into a veffel filled with the vapour of
water, we obtain lac fulphuris of the ufual whitenefs, inftead
of the ufual flowers of fulphur, Thefe faéts prove that lac ful-
phuris is a. compound of fulphur and water. Hence we may
conclude that greenifh yellow is the natural colour of fulphur,
Whitenefs indicates the prefence of water.
Sulphur render- 2, It has been long known, that when a confiderable quan-
priest tity of fulphur is kept melted for fome time in an open veffel,
by fufion. it becomes vifcid, changes its colour to a dark violet, and ac-
quires a kind of pitchy appearance. The nature of this change
has not hitherto been examined by chemifts. Fourcroy, in-
deed, affirms, that the fulphur, in this cafe, is in the ftate of
an oxide. But the affertion does not feem to have been the
refult of any pofitive experiment.
Doesnotfueceed J have never been able to produce this change in the ap-
in a fhallow vef- Soar : :
fel. pearance of fulphur by heating it in a flat difh, where nothing
impedes the volatilization, though I have kept it melted in a
glafs capfule on fand, heated to 250°, for ten hours toge-
ther. But the change takes place in a fhort time, when a con-
fiderable quantity of fulphur is kept melted in a crucible; and
the greater the quantity employed, the fooner the change is
produced, and the more complete it is.
Thfs fuppofed When fulphur, thus converted into a fuppofed oxide, is
oxide is of a vio~ 5 : : 5
let colour; is foft M¢Wly prepared, its colour is a dark violet, with the metallic
if pouredinto luftre ; not very unlike newly-melted muriate of filver, when
pag siviaetirans feen by reflected light. If it be thrown fuddenly, while in
phur; and tough. fufion, into water, it continues foft for a confiderable time.
and, as it hardens, the colour changes from purple to reddith
yellow. When broken, it exhibits a fibrous fraéture, com-
pofed of fmall prifmatic cryftals: Its fpecific gravity was
2.325. It was very tough, refifting, with a good deal of ob.
4 ftinacy,
~
OF THE COMPOUNDS OF SULPHUR AND OXYGEN. 103
ftinacy, the aétion of the peftle. The powder hada ftraw
yellow colour. Its properties differ, we fee, from roll fulphur,
which is remarkably brittle, and whofe {pecific gravity does
not exceed 2.
To afcertain whether this fuppofed oxide really contained It feems to con-
oxygen, I treated 100 parts of it with nitric acie till the whole a coal
was converted into fulphuric acid. The procefs was as te- though perhaps
dious as the acidification of common fulphur, by means of the pee oe
Te X ‘ i I e it to the
fame acid. By nitrate of barytes I obferved a precipitate, name of oxida.
which, after being reddened in a platinum crucible, weighed
667, indicating 160 parts of fulphuric acid; the fuppofed
oxide had abforbed, of courfe, 60 parts of oxygen. Hence
we have fulphuric acid compofed of
62.5 fuppofed oxide
37.5 oxygen
100.0
But 100 part of pure fulphur would have abforbed nearly 64
of oxygen, and formed 164 of fulphuric acid. Hence it follows
that the fuppofed oxide is compofed of
97.6 fulphur
2.4 oxygen
100.0
Though the refult of a fimilar experiment was nearly the
fame ; yet the proportion of oxygen is certainly too {mall to
authorize us, in the prefent ftate of chemical analyfis, {o con-
clude that the fuppofed oxide really contains 24 per cent. of
soxygen : for fo fmall a deviation from the compofition of fulphu-
ric acid, by acidifying common fulphur, as 2% per cent. may,
very probably, be owing to an error of analyfis. At the fame
time the uniformity of my refults inclines me to believe that
this fuppofed oxide of the French chemifts really contains
- fome oxygen. |
3. As no fatisfaGtory refult was likely to be obtained by ex- Oxigenation of
pofing fulphur to heat and air, it became neceflary to try the ate Os
effeéts of thofe chemical agents which are capable of commu-
_ nicating oxygen to other bodies. Sulphuric acid could not be
ufed, becaufe fulphur converts it into fulphurous acid; the
effe& of nitric acid was well known; but the action of oxy-
-muriatic acid had not been tried, Some of the foreign chemitts,
indeed,
104 ON THE COMPOUNDS OF SULPHUR AND OXYGEN,
indeed, affirm that fulphur takes fire when plunged into that
gas; but they muft have, fome how or other, deceived them-
felves.
Oxigenation by 1 conneéted three Woulfe’s bottles in the fame manner, by
oxymuriaticacide means of glafs tubes; furnifhed each with Welter’s tubes of
Balen Sx Poa fafety. The firft contained an ounce troy of pure dry flowers
gas was convert- of fulphur; the fecond was filled two-thirds with diftilled
pete, pike water; and the third with a weak folution of cryftallized car-
red liquid. bonate of potafh. A current of oxymuriatic acid gas was made
to pafs through thefe bottles in the ufual way. The procefs
lafted a confiderable time. The firft bottle was foon filled
with the greenifh fumes of the gas; the fulphur gradually be-
came moift and doughy, and the particles of it which adhered
to the fides began to trickle down in drops; its colour changed
to orange, and at laft, a fine red liquid made its appearance,
The whole of the fulphur was gradually converted into this
liquid. I then ftopt the procefs. Abundance of gas had
paffed through all the bottles; the water in the fecond was, at
one time, quite milky, but it recovered its tranfparency before
the procefs was finithed. Dots of {ulphur were depofited
along the glafs tubes which conneéted the firft and fecond
phials ; but none in that which conneéted the fecond and third,
the folution in the third phial effervefced precifely as in the ufual
procefs for preparing hyper-oxymuriate of potafh, The gas:
which efcaped was carbonic acid. No oxymuriatic acid gas
could be diftinguifhed by its {mell in the {mall capfule of water
into which a tube iffuing from the third bottle was pluaged.
«=~ denominated As the red liquid obtained by this procefs has never before
Cin aaa been examined by chemifts, and, as it differs very much in its
properties from all other fubftances at prefent known, it will
be neceffary to diftinguifh it by a peculiar name, I fhall call it
fulphureted muriatic acid, till fome better name be thought of,
== more than This liquid amounted to 1$ ounce meafures, exclufive of
double the what adhered to the fides of the bottle; its i :
weight of the in ol fpecific gravity
fulphure was 1.623, It amounted, therefore, to 2.63 ounces, or more
than twice the weight of the fulphur, exclufive of what had
been volatilized during the procefs.
It is green by Sulphureted muriatic acid is perfedtly liquid ; its colour is a
gai fine red, intermediate between fcarlet and crimfon. When
ftreaks of it run down the infide of the phial, they appear
green by tranfiitted light, .
When
ON THE COMPOUNDS OF SULPHUR AND OXYGEN, 105
* When expofed to air, it fmokes at firft almoft as intenfely as It {mokes, and
the .fmoking oxymuriate of tin of Lebavius; but the intenfity eae
gradually diminifhes, and, at laft, refembles that of the moft con- dens blue colour;
centrated muriatic acid a little heated. It is very volatile, ae tee:
. : ; umes by ap-
difappearing very rapidly when expofed to a moderate heat. proach of am-
Its fmell has a ftrong refemblance to that of fea-plants, but 07145 and when
® : dropped into
is much ftronger. The eyes, when expofed to its fumes, are water, leaves a
foon filled with tears, and acquire the fame painful feeling as Ae of signer:
when expofed to the {moke of wood or peat. acids du@ie, tte
Its tafte is ftrongly acid, hot, and bitter, affe@ting the throat gee flakes
with a painful tickling. By ee
It converts vegetable blue papers to red; but the change
. takes. place flowly, unlefs the paper be dipt into water; the
paper is not corroded unlefs heat be applied.
When brought near a phial of ammonia, denfe white fumes
of muriate of ammonia make their appearance. © If it be held
above a folution of nitrate of filver, yellow flakes precipitate
in abundance. .
If adrop of fulphureted muriatic acid be let fall into a glafs
of water, the furface of the water becomes immediately co-
vered with a film of fulphur; a greenifh red globule falls to
the bottom, which remains for fome time like a drop of oil,
but at laft is converted into yellow flakes; thefe flakes have an
acid tafte, which they do not lofe, though allowed to remain
in water for feveral days; they are very duétile, and continue
fo, though left expofed to the air.
4. To afcertain the conftituents of this liquid I agitated 110 Chemical exami-
parts of it ina very weak folution of potath, and then threw liquid Sane
the whole on a filter: a yellow duétile fubftance was fepa- reted muriatic
rated, which adhered very firongly to the filter ; what I could #4
feparate was put on a plate of glafs,and dried gently in the open
air. It weighed 40, This fubftance had a yellow colour, and
refembled half dry oil paint ; its tafte was hot; it adhered fo
obftinately to the finger, that feveral days elapfed before every
trace of it difappeared. When digefted for fome time in hot
water, it fell into flakes of fulphur, and the water acquired an
acid tafte. The flakes weighed only 34, and poffeffed all the
properties of common fulphur. The water in which it had
been digefted yielded, with nitrate of barytes, a precipitate
which weighed 8, indicating the prefence of 1.92 fulphuric acid
with nitrate of filver ; the precipitate amounted to 16, indicat-
| ing
, .
106
Chemical exe
mination of the
red liquid or ful-
phureted muriatic
acide
Remarks on the
fulphuret of mue
Yiatic acid,
ON THE COMPOUNDS OF SULPHUR AND OXYGEN.
ing 2.88 muriatic acid: but the precipitate had a brownifh
tinge, of which muriate of filver is deftitute. The 40 parts of
yellow refiduum then contained
34.00 fulphur
1.92 fulphuric acid
2.88 muriatic acid
1.20 water or lofs
40.00
Seventy parts {till remain to be afcertained. They muft exift |
in the folution of potafh. This folution, fuperfaturated+ with
nitric acid, and treated firft with nitrate of barytes, and next
with nitrate of filver, yielded precipitates indicating the pre-
fence of 4.8 fulphuric acid and 36.45 of muriatic acid. The
refiduum yield no farther precipitate with filver; but, when
evaporated to drynefs, fome yellow cryftals were obtained,
which gave traces of fulphur, but in too fmall quantity to be
weighed. This analyfis gives us the following proportions :
35.00 fulphur
39.33 muriatic acid
6.72 fulphuric acid
81.05
28.95 lofs
110.00 .
or per cent. 31.82 fulphur
35.75 muriatic acid
6.10 fulphuric acid
os
73.67
26.33 lofs .
This enormous lofs was owing, at leaft, in part, to the im-
probability of feparating from the filter, the whole fulphure-
ous mafs fo as to weigh it. This induced me to have recourfe
to the following method of afcertaining the proportions of ful-
phur in fulphureted muriatic acid.
When fulphureted muriatic acid is thrown into warm nitric
acid a very violent effervefcence takes place, and the whole
mixture is thrown, witha kind of explofion, out of the veffel.
If the acid be cold, the effervefcence is at firft flow, but heat
is very foon evolved, and the fame effeéts produced. When
the proportion of nitric acid is great, and. the fulphuret dropt
in
ON THE COMPOUNDS OF SULPHUR AND OXYGEN. 107
ut very flowly, the effervefcence continues moderate ; nitrous Chemical exa-
gas and oxymuriatic gas being evolved, as was evident, from red liquid ore
the fmell. I diffolved 100 parts of the fulphuret in nitric péureted muriatic
acid. The liquid yielded, with nitrate of barytes, a folution #4
which, when properly dried, weighed 282 parts, indicating
67.6 parts of fulphuric acid; but 67.6 of fulphuric acid con-
tain 26.3 oxygen. Hence 100 parts of fulphureted muriatic
acid contain 41.3 of fulphur.
If a cryftal of muriate of barytes be fufpended in fulphureted
muriatic acid, no precipitate takes place ; neither was any ob-
tained by agitating this falt in powder with the fulphuret.
Hence I conclude, that the fulphuret does not contain fulphu-
ric acid ; but that fulphuric acid is formed whenever the liquid
comes in contaét with water. The oxygen cannot be fup-
pofed to have been previoufly united to the muriatic acid fo-
lution. For I find, by trial, that if the oxymuriatic acid gas be
ftill made to pafs through the fulphuret, after it is once formed,
fulphuric acid immediately makes its appearance in it. The
oxygen then muft have been combined with the fulphur; the
whole of which was in the ftate of an oxide. Whenever the
fulphuret is diluted with water, that oxide undergoes decom-
pofition, one portion of it abftraéting the whole of the oxygen
from the other, fo that fulphuric acid and fulphur make their
appearance together.
If we fuppofe the proportion of fulphur and fulphuric acid
obtained by the firft analyfis to be that which is formed when
the fulphur is mixed with water, we fhall have the oxide of
fulphur compofed of
31.82 fulphur
6.10 fulphuric acid
or of 35.54 fulphur
‘ 2.38 oxygen
or per cent. of 93. 8 fulphur
6. 2 oxygen
100. O
But the fulphuret yielded to nitric acid 41.3 per cent. of
fulphur. Hence it muft contain 44 per cent. of oxide of ful-
phur. Sulphureted muriatic acid then contains
44,00 oxide of fulphur
35.75 muriatic acid
20.25 lols
100.00
108 ON THE COMPOUNDS OF SULPHUR AND OXYGEN.
Chemical exa- The lofs is ftill very confiderable. Probably the greater part
mination of the of jt is owing to the prefence of water ; the amount of which
red liquid or ful- |, :
pbureted muriaticit is impoffible to afcertain.
acide The above analyfis conveys but an inadequate idea of the
conftitution of fulphureted muriatic acid, becaufe the propor-
tions of its conftituents vary confiderably, according to the pro~
cefs. The longer the procefs is continued the greater is the
encreafe of muriatic acid, and the fmaller the- proportion of
oxide of fulphur. 1 found a portion of fulphuret thus formed
to contain 47.1 muriatic acid
35.2 oxide of fulphur
4.0 fulphuric acid
——
86.3
13.7 lofs
It was this laft fulphuret that was obtained in the procefs in
which the quantity of fulphuret which I got, as ftated above,
was meafured, the fecond Woulfe’s bottle contained a folution
of muriatic acid and fulphuric acid in water. Hence we fee
that the fulphuret, after being formed, had been partly covered
over by the oxymuriatic acid gas. The fulphuric acid ob-
tained, by means of barytes, amounted to 36 grains; the mu-
riatic acid to 139 grains. The third vial contained no fulphu-
ric acid, but confifted of a mixture of muriate of potath, hyper-
oxymuriate of potafh and carbonate of potafh.
Remarks on the 5, The fulphuret of muriatic acid claims the peculiar at-
fulphureted mu- : - ; ae ;
Sete, tention of chemifis, not only on account of its compofition,
which our previous knowledge would have induced us to _
confider as impoffible, but on account of the many remark-
able properties whch it difplays. As I mean to referve a
full account of its properties for a fubfequent paper, I fhall
fatisfy myfelf at prefent with the following remarks.
Sulphuret of 1. Sulphuret of muriatic acid diffolves phofphorus cold
oe acid dif- with great facility. No effervefcence takes place ; the folu-
olves phofpho- |. :
use tion bas a fine amber colour, and is permanent. When eva-
porated, the phofphorus remains behind with a little fulphur,
and at laft takes fire. When the folution is mixed with liquid
potath, the whole becomes beautifully luminous, and_phof-
phuret of fulphur is precipitated.
Sulphuret effer- 2. When mixed with alcohol, a violent effervefcence is
vefces with al- produced, ether is immediately difengaged, and, what I did
cohol, and forms
ether. not
EFFLORESCENCES OF WALLS, ~ 109
not expe? : this ether is mixed with fulphurous acid, and muft
be re@tified in the fame way as fulphuric ether, which it refem-
bles in fmell. ;
3. All the acids decompofe this fulphuret, fulphur ufuallyis difcompofed
precipitating, except liquid fulphurous acid, which produces>y 4! acids 5
no change, and nitrous acid, which diflolves and decompofes
it at the fame time.
4. The fixed alkalies dry produce with it a violent effervef-habitudes with
cence and a very high degree of heat. When ammoniacal™ <5
gas is paffed through it, the veffel is filled with a fine purple
fal-ammoniacal {ssoke, the whole becomes folidand of a deep
red colour; but when mixed with water, fulphur is immedi-
ately precipitated.
5, This liquid precipitates filver of a yellow colour mixed precipitates fil-
with white, the white is a muriate of filver, the yellow is LS aera A
compound of the oxides of filver and fulphur. It becomes
brown when dry. Nitric acid decompofes it, diffulving the
filver and acidifying the fulphur.
iyi
Further Experiments and Obfervations on the Efflorefcenees of
Walls. Ina Letter from Dr. Bostock.
To Mr. NICHOLSON.
STR,
INCE I fent you the analyfis of the faline efflorefcence Four eMoref-
from the walls of Mr. Earle’s houfe, inferted in your journal: 0° ear
for November laft, [ have had an opportunity of examining
four other effloref{cences obtained from brick walls, the parti-
_ culars of which I thall now detail.
The firft of thefe was prefented to me by my friend Dr. ve firft ving
Rutter, who difcovered it in confiderable quantity on the top Sie esi
of the walls of his houfe juft below the roof. This falt hadnefia
in every refpeGt the fame external chara¢ters with the one
which I had before examined, and upon fubmitting it to the
aétion of the fame chemical re-agents, fimilar refults were ob-
tained. In addition to the former experiments, I compared
the effeéts produced upon it by pure ammoniac, and by the
éarbonate of ammoniac ; the former threw down a copious
: preci-
110 EFFLORESCENCES OF WALLS.
precipitate, while the latter had no perceptible operation ; 4
decifive teft of the exiftence of magnefia, which was fug-
gefted to me by Mr. William Henry of Manchefter. This
falt appeared, therefore, tobe a very pure fulphate of mag-
nefia.
The fecond ef- The fecond efflorefeence which I examined. was obtained
ad pe) from the outer wall of a ftable, which had been ereéted for
with indication fome years. It differed on its appearance from the two
of muriatic acids eer; inftead of fhooting out from the wall in fpiculz of
confiderable length, it appeared like a powder feattered over
the furface, occupying diftinét, round patches, fo as in fome
degree to refemble the growth of a grey lichen. The bricks
on which this efflorefcence appeared were in general of a
2 fofter texture than thofe of the reft of the wall. Though it
occupied a confiderable extent, it was difficult to colleét it in
any quantity, -but I obtained fufficient to fubjeét it to the fol-
lowing experiments. The falt was diffolved in warm water,
filtered and cryftallized ; the cryftals were very foluble at the
common temperature of the atmofphere. Muriate of Barytes
added to the folution produced a copious precipitate; car-
bonate of pot-afh, pure pot-afh, pure ammoniac and oxalic
acid were refpeétively added to the folution, but produced no
effect. Nitrate of filver caufed a precipitate, but only in
{mall quantity. From thefe experiments it appeared that the
falt in queftion confifted of the fulphuric acid, mixed with a
fmall proportion of the muriatic, and combined with one of
the fixed alcalies. From the form of its cryftals I conceived
that the fulphuric acid was in this cafe united to foda, but the
quantity of falt which had been procured, was not fufficient
to enable me to determine accurately from this circum-
ftlance. A more decifive teft between the fulphate of foda
and the fulphate of pot-afh, is the property which the latter
alone poffefles of forming alum with the acid) fulphate. of
alumine, I accordingly prepared a quantity of this fubftance ;
to one portion of it fulphate of pot-ath was added, and to the:
other fome of the falt under examination. By gentie evapo-
ration and fubfequent cooling, the firft produced very evident
cryftals of alum, the latter only formed a confufed mafs. This.
I confidered as a fufficient proof that this faline efflorefcence
was the fulphate of foda. .
Third efforef- Lhe third efforefcence was obtained ‘from the inner wine of
cence {ulphate a brick houfe which was then ereéting ; it had all the internal
chae
, EFFLORESCENCES OF WALLS. 111
chara¢ters of the faline efflorefcence from the ftable, and whenof foda nearly
fubmitted to the fame chemical re-agents, differed from itP’'®
only in exhibiting flighter traces of the muriatic acid; this
falt was therefore a fulphate of foda nearly in a ftate of
purity.
The walls of the falt water baths in this town are covered Fourth efMoref-
with a ftucco, which is in feveral places bliftered and moulder-ir.? or pe
ingaway. ‘The parts of the plaifter which are decaying, are water bath, was
covered with a copious efflorefcence, which has the appear-°*bonate of foda,
ance of a fine white down. Some of this I colleéted and
examined. It was diffolved in warm water and filtered; the
folution was not capable of being regularly cryftallized, but
formed a white mafs, eafily foluble, poffefling the acrid tafte
of a fixed alcali, and affeéting the colour of teft papers in the
fame manner. A brifk effervefcence was excited by the ad-
dition of an acid, and from this circumftance and the effe@ of
the different re-agents, I conceived it to be one of the fixed
alcalies. In order to determine whether it was an uncom-
bined alcali, and to which of thefe bodies it ought to be re-
ferred, I afcertained what quantity of the fulphuric acid was
requifite to faturate a known weight of the falt, and after-
wards, employing the fame acid, compared it with the quan-
tity which the fame weight of alcali required. As the falt
had not attraéted any moifture from the atmofphere during a
period of fome weeks, I eoncluded it to be foda, and I ac-
cordingly found that the fame quantity of fulphuric acid fafu-
rated equal weights of foda, and of the falt under examina-
tion; the folution being flowly evaporated, formed well- ,
marked cryftals of the fulphate of foda. That part of the
walls of the bath on which the falt had efflorefced in the
gteateft quantity, was out of the reach of the immediate
action of the fea water; but it is probable that the fand of
the fhore had been mixed with the lime, for by examining a
quantity of water which had been digefted upon a portion of
the plaifter, it yielded a very copious precipitation by the ni-
trate of filver, and this rendered it highly probably that the Probably formed
mortar contained the muriate of foda. It might therefore beby procefs for-
conjeCtured that the foda in this cafe was accidentally formed ¢, ey re
by the fame procefs which, according to Mr. Accum’s sCcount
in the 2d vol. of the Journal, p. 243, is employed defignedly
in Pruffia for obtaining it, by the decompofition of common
dale...
I hall
112 EFFLORESCENCES OF WALLS.
Invettigation of I fhall conclude this communication by detailing to you the
the origin of ~~ progrefs which 1 have made in inveftigating the origin of the
ao ere -- fulphate of magnefia, which appeared in Mr. Barle’ s houfe.
bricks of Mr. Before proceeding farther, it will be proper to obferve that
Eaile’s houfee the efflorefeence was here altogether confined to the bricks,
the mortar which united them being entirely free from it, and
that rain water only had been employed in tempering the clay.
It remained therefore to examine with accuracy, whether any
falt, foluble in water, exifted ready formed in the clay, and
what were the component parts of the clay itfelf. To afcer-
tain the firft of thefe points, 60 grains of the clay. powdered
and dried were well wafhed with boiling water; the water
was filtered and evaporated, and the refiduum carefully col-
The clay con Jegted; it did not weigh 4 of a grain. It was re-diffolved in
tained a por- is i pts :
tion of mu- water; it produced a copious precipitate with the muriate of
riate and fulphate barytes, and the nitrate of filver; a very. faint cloud with
ea oxalic acid and with pure pot-afh; ammoniac produced no
effect. The ready formed falts appeared therefore to be the
fulphate and muriate of a fixed alcali, with a minute fortion of
the muriate of lime, the whole however exifting in very {mall
quantity, \
ee a ee The clay itfelf was next examined ; it was found to.confitt
ortion OF mage . . > . . I .
a. : principally of filex and alumine in the proportion of about
three to one; the quantity of lime was very fmall, though
its exiftence was detected by the oxalic acid; its colour
Wed that it contained iron, and I alfo found that about
ive parts in the 100 confifted of magnefia. From this exa«
mination it appeared that one of the component parts of the
falt exifts in the ‘clay ; I attributed the formation of the ful-
phuric acid to the fulphur which is frequently met with in our
coals, and which I conceived might unite with oxigen, during
Experiment to the burning of the bricks, _I attempted to put. this aétion to
fhew whether :
fidietu gf Rett the teft of experiment, and accordingly I formed a. pafte of
coals had given pipe clay and calcined magnefia in the proportion of 95 to
“igi aici five ; this was placed in a crucible, furrounded. with {mall
coal mixed with a quantity of fulphur; the crucible was then
kept for fome time in a firong heat. I was not able to dete@ |
the prefence of the fulphuric acid in the clay that was thus
baked, but fo many circumftances. might .aétually take place
in the formation and burning of the bricks, which we have it
not in our power to imitate in the laboratory, that I do not
confider the hypothefis difproved by my want of fuccefs.
In
EFFLORESCENCES OF WALiS. 113
Th analyfing the clay I proceeded nearly upon the plan Analyfs of the
pointed out by M, Vauquelin in the 30th vol. of the Ann, Slay, &c.
de Chimie.
This operation is however fo tedious, and requires fo much
nicety in the management, that I made fome attempts to af=
certain the exiftence of magnefia in the clay by a fhorter pros
eels. The firft method which I employed was fuggefted by
an obfervation of Mr. Kirwan; he ftates that alumine is fuf-
ficiently difcriminated from magnefia by the greater folubility of
the latter in dilute fulphuric acid ; but it appears that the dif-
ference of folubility of thefe two fubftances cannot be em-
ployed as a teft of the prefence of magnefia where it exifts
only in fmall proportion ; for I found that the fulphuric acid:
diluted with above 200 times its weight of water, after being
in contaét with pure alumine for the {pace of 10 minutes only,
had acted upon the alumine fo far that a precipitate was
formed in the fluid by the addition of ammoniac,
The acetous acid is ftated as pofleffing a much more power-
ful ation over magnefia than over alumine; but upon trial
the fame objeétion occurred againft its ufe as in the former
inftance,
The property which the magnefian falts poffefs of being
decompofed by pure ammoniac but not by the carbonate:of
ammoniac, feemed to offer a method by which the fulphates
of magnefia and of alumine might be feparated when mixed
together in folution, and by which means confequently t *
prefence of magnefia might be dete@ted in the clay under
examination. But I found that though the fulphate of mag-
nefia alone is not decompofed by the carbonate of ammoriiac,
_ yet that when a mixed folution of alum and the fulphate of
magnefia is fubjected to the a€tion of the carbonate of ammo-
niac, both the alumine and the magnefia are precipitated, fo
_ that when the fluid is feparated by filtration, the addition of
pure ammoniac produces no farther effeét : fe
After I had made the unfuccefsful experiment related above
refpeéting the formation of the fulphuric acid, I receivéd the
laft number of your Journal, containing a communication from
Mr. Gregor, in which he gives an account of the produétion
of the fulphate of magnefia from the afhes of pit-coal. He Mt.Gregor’s ete
attributes the produétion of this falt to the decompofition of periment notape
_ the fchiftus and pyrites which are commonly found in coal, ope ao
VoL. VI.—COctoner, 1803, I and as coal afhes
were not uled,
314
ON EVAPORATING FURNACES.
and by heating a mixture of thefe fubftances he fucceeded in
forming the falt artificially. The fuccefs of his experiment
feems to prove the truth of the theory, at leaft in the parti-
cular inftance in which he obferved the efflorefcence : but in
thofe cafes where the falt evidently proceeds from the fub-*
ftance of the brick, and where the magnefia has been found
to exift previoufly in the clay, the idea of Mr. Gregor appears
lefs applicable, fo far as regards the origin of the magnefia ;
but in both the proceffes the fulphuric acid is equally fuppofed
to be derived from the pyrites. Mr. Gregor fuggefts that coal
afhes might have been mixed with the clay of which thefe
bricks were formed ; but I find upon enquiry that this was
not the cafe.
Iam,
Liverpool, Aug. 30, Your obedient fervant,
1803. JOHN BOSTOCK.
a a PS SSS SSE SE SY
be
Philofophical Obfercations on the Caufes of the Imperfeétion of
evaporating Furnaces, and on a New Method of conftructing
them, for the economical Combuftion of every Defcription of
Fuel. By C. Curaupau, correfponding Member of the
Pharmaceutic Society of Paris *.
On the come W orwirustanpinc the attempts already made to
buftion of fuel
end conftruétion
of furnaces.
introduce ceconomy in the ufe of the combutftibles neceffary to
the manufactures, we ftill ufe them with confiderable wafte,
In all cafes a much greater quantity of fuel is confumed than
is needful to keep up the ebullition in evaporating furnaces,
or to produce the requifite temperature in furnaces for other
purpofes. It may be eafily conceived that this fuperfluous con-
fumption muft in large eftablifhments be attended with great
lofs, and muft eventually tend to produce a fcarcity of fuel in
the market. It therefore becomes us for both reafons to en-
deavour to prevent a fcarcity, of which future generations
might with juftice accufe us of being the authors, unlefs. we
ferioufly occupy ourfelves in fearch of the methods of burning
wood with more economy, Many very remarkable improve-
® From the Annales de Ghimie, No. 138¢
ments
ON EVAPORATING FURNACES. 115
ments have indeed been made in the conftruétion of furnaces On the com-
within thefe few years, but they are only advances towards pe fain
perfection, and are yet very far from being carried to the ex-of furnaces.
tent of which they are capable. This will no doubt be the
cafe with the alterations Iam about to propofe ; for thefe will
enable us to make new obfervations, which moft probably will
lead to further alterations ftill more important.
Concerning Evaporatory Furnaces.
The phyfical impoffibility of raifing the temperature in eva-
porating furnaces as they are at prefent conftruéted, is one of ©
the caufes which has always appeared to me moft ftrongly in-
imical to their improvement. For it muft not be imagined that *
the intenfity of the heat will be in proportion to the quantity
of. matter in ignition, or that caloric will not be more copi-
oufly produced by the fame quantity of combuftible under
certain circumftances than others; as for example, when the
temperature is already very high, the produéts of heat from a
combuftible fo fituated will be much more confiderable than
thofe from the fame combuftible burned in a furnace, the tem-
perature of which is conftantly depreffed by the evaporation of
the liquid in the boiler.
To prove that it is only by virtue of a temperature already
elevated that we can obtain an advantageous combuttion, I fhall
take Argand’s lamp, which will afford a comparative inftanag
on a fmall fcale of the effeét produced by the intenfity of heat
during combuftion. When thefe lamps have their glafs chim-
“ney, they afford a very brilliant light, and the oil will emit no
fmoke. But if the chimney be taken off, the oil will immedi-
ately burn duller, the light will be lefs intenfe, and the wick
will give out fmoke. This effeét fhews that it is the current
of air in the chimney, and the heat it keeps up round the wick,
which contributes to the effeét of the combuftion. What fill
adds weight to this opinion is, that the perfection to which this
kind of lamp is brought depends principally on the form and
proportions of its glafs chimney.
This example muft then naturally lead us to think that eva-
porating furnaces, as they are made at prefent, cannot advan-
tageoufly promote combutftion, fince the bottom of..the boiler,
which is continually kept at the fame degree of heat by the
evaporation of the liquid in boiling, conftantly prevents the
. 12 rife
116
On the com-
buftion of fuel
and conftru€tion
of furnaces.
ON EVAPORATING FURNACES.
rife of the temperature, whence it refults that the heat whieh
is infufficient to produce a complete combuftion of the inflam-
mable particles, will rather produce gazification than oxigi-
nation. This volatilization of the particles of combuftible
bodies which efcape combuftion, and’ which pafs fucceffively
into the ftate of permanent gales, will alfo abforb a quantity
of heat neceffary to their gafeous conftitution, which, together
with the effeéts of the current of air, will tend to lower the
interior temperature of the furnace, and to ae the procefs
of combuttion.
Thefe remarks, which perfeétly agree with all the pheno-
men of combuftion, thew that the oxigen of the atmofphere
does not act with much efficacy on ccinabiulite bodies, except
when they are immerfed in it at an high temperature, and that
to apply an intenfe and uniform heat to an evaporating furnace
without lofs of the combutftible, it fhould be produced in a fire-
place, having a current of air, and fo far diftant from the boiler
that the temperature may be raifed gradually and at pleafure.
By this means all the particles of the combuftible matter will
be in a ftate favourable to their oxigination; and the whole
quantity of radiant heat produced by the reaétion of the oxi-
gen upon the combuftible, will be difengaged and employed
without lofs.
That which under fimilar circumftances conduces ftill farther
‘to encreafe the action of the oxigen, is its continual renewal.
For the higher the temperature of -a furnace is raifed the more
eafily the outer air will enter; and fo likewife when the igni-
tion is carried to a high degree, it becomes neceflary and ad-
-vantageous to check the current of air, not by clofing the door
or lower opening of the furnace, as is generally done, but ra-
ther by contraéting or even clofing the upper aperture of the
chimney. By this means the heat becomes concentrated in
the body of the furnace, and has no other paflage than through
the liquid in the boiler,
This remark on the method of checking the current of air .
by the top of the chimney, may alfo be applied to furnaces of
fufion, and in cafes where it is required to maintain the heat
of a metal without expofing it to the oxigenating aétion of a
current of air in a ftate of ignition.
General
ON EVAPORATING FURNACES.
General Remarks on the Conftruétion of Furnaces.
That part of the fire-place which is to fupport the greateft
heat, fhould be made of very refractory bricks. The beft ce-
ment or mortar for bricks, in all cafes where a bad conductor of
heat is required, is a mixture of equal parts by meafure of tan
and-clay. The tan prevents the cement from cracking, and
produces an adhefivenefs which, when dry, gives it a great
degree of firmnefs.
Furnaces may alfo be conftruéted with this Bre and on
the fame principles with thofe of evaporation, which Iam about
to defcribe. :
_ Furnaces intended for ftrong heat, fhould be externally co-
vered with a thick wall, conftru€ted with the mortar of tan,
By this means very little heat will be loft. All furnaces fhould
be fo conftru€ted as to have the power of clofing the upper
aperture of the chimney at pleafure, in order to check the
combutftion, and concentrate the heat within the furnace, when-
ever this becomes neceffary. When the temperature is very
high, it is particularly neceflary to regulate the iffue of the
current of air fo as to prevent its too {peedy circulation through
the furnace, which, in certain cafes, is prejudicial to the fuc-
cefs of the operation.
By uniting all thefe conditions in furnaces, a certain faving
ef one fourth of the fuel will be made, and the combuftion
will be produced without any appearance of {moke. I infitt
more particularly on this remark, becaufe it is clearly and phy-
fically proved that no combuftible « can be completely burned
if {moke be produced.
Defeription of an Evaporating Furnace, in which the Temperature
may be ruifed at Pleafure.
117
For common furnaces, the aperture of the vaylt A, Plate Defcription of
VI. thould be four decimetres (153 inches) wide, by three # furnace ia
decimetres and a half (13% inches) in height; B is the part of
_ the vault in | which the combultion is performed. This vault
- muft be. at. leaft two metres (64 feet) inlength, C reprefents
_a boiler of one metre and a half (nearly five feet) in diameter,
and of the fame depth; it is fet in a brick furnace.
The interval from the bottom of the bojler to the bafe of the
furnace muft be at moft one decimetre (about four inches.) It
mutt be obferved in the conftruction of furnaces, that the brick-
work fhould be gradually floped towards the boiler, and to re-
duce
evaporation.
118 STATE OF VAPOUR IN THE ATMOSPHERE.
duce the fpace to about three centimetres (about an inch.) It
muft be thus continued to within one decimetre of the edge of
the boiler ; and muft then be brought into contaét with it. D is
an aperture of two decimetres wide by one in height (about eight
inches by four) communicating with E. But at the fide of the
angle a, this paflage for the heat muft be made of one metre
(three feet three inches) in width, by one decimetre (about
four inches) in height, and this proportion continued to the
aperture E.
F is a fecond boiler, intended to be heated by means of the
excefs of heat from the firft; many others may be applied in
fucceffion, if required. G is an aperture with the fame pro-
portions as D, At the angle b, it muft be obferved to’ make
the aperture of the chimney five decimetres by two (192 inch.
by 73 inch.) and to continue this proportion to about two thirds
of its height. The aperture may then be contraéted fo that, at
its upper extremity, it may not be lefs than one decimetre by
three (about four inches by twelve.) This part of the chim-
ney fhould be fo conftruéted as to be able to clofe it conveni-
ently, when required,
Se en
XI.
Correction of a Miftake in Dr. Kirwan’s Effay on the State of
Vapour in the Atmofphere. By Mr. DaTon.
To Mr. NICHOLSON,
o 18,
aise: I TAKE the liberty of requefting you to corre&t a miftake in
ing Mr. Crof- Dr. Kirwan’s effay on vapour, copied in your laft number,
pase page 246. In treating upon the height of clouds, he obferves,
mum heightof “ In lat. 54°, in Cumberland, Mr. Crofthwaite obferved none
the clouds. “lower than 2700 feet, and none higher than 3150, in the
“« courfe of feveral years.” For this he refers to my meteoro-
logical obfervations, page 41. The faéts there ftated, how-
ever, are fo very different from thofe above mentioned, that I
conclude Dr. Kirwan has not feen the book, and has been
mifinformed. The account referred to is, that Mr. Crof-
thwaite obferved the heights of the clouds ufually three times a
day for five years, by remarking their interfeGtion with Skid-
daw (a high mountain near Kefwick.) ‘The refult was,
4 Clouds
STATE OF VAPOUR IN THE ATMOSPHERE, 119
Clouds from 0 to 100 yards above Derwent Lake, 10 times.
WOMWBABI4 2S) WBisinp peli’ ow 49
200'3'''300)" ¢ae,e 6 - - 62
' 300 - 400 - - - - 179
400+ 500 - ab ive - 374
500 - 600 2 sHiiogts' jews 486
600 4),,700 (4 Pee © . 416
FOO\S>-800 i200 )\« - - 367
s00- 900. -« - aratt 410
900 - 1000 ~ abvatlgerd smd ce SB
1000- 1050s - site he & 419
above 1050 ° - = - 2098
———
Total 5381
His obfervations could not be particular above 1050 yards, No maximum
that being the perpendicular height of Skiddaw. There is not ei 4s dias
therefore any maximum of height fo much as hinted at ; and author’s obfer-
the minimum is 0, or when the clouds reft on the sea iin
event occurring in every part of Great Britain two or three
times a year. Were we to forma conjeéture from the above
obfervations relative to the greateft height at which clouds are
formed in this country in ordinary, it would be about 1 mile;
but in fummer they are probably fometimes 1} mile above
the level of the fea.
Confidering the great fervice that Dr. Kirwan has rendered Obfervations, or
to meteorology and chemiftry, and my own obligations to him a age
on thofe accounts, it is unpleafant for me to fignify diffent from and Mr. Dalton’s
the doétrine he inculcates refpeéting the ftate of vapour in the ellos
atmofphere. At the fame time that his interefting feries of pheric vapours
eflays in the eighth volume of the Tranfaétions of the Royal
Irith Academy were in the prefs, my effays on the force of va-
pour from water and other liquids, both in a vacuum and in
air, and on evaporation, publifhed in the Manchefter Tranf-
aétions, Vol. V. Part 2, were alfo in the prefs. He holds the
notion of a chemical folution of water in air; and I maintain
that vapour fubfifts in air as it does in vacuo, conftituting a pe-
culiar atmofphere, mixing but not combining with any of the
gafes of the compound atmofphere. On my principle the den-
fity of the aqueous atmofphere at any height is totally inde-
pendent of the denfity of the compound mafs of - air, and is
to be afcertained by ‘knowing the denfity of vapour at the
earth’s
120
Eafy method of
fecuring decayed
timbers in builds
ings, &c.
METHOD OF SECURING DECAYED TIMBERS...
earth’s furface, and its fpecific gravity ; in the fame way as
we would afcertain the denfity of the oxygenous or azolic at-
mo({pheres, or one of hidrogen, at any given height, having
the like data.
It has been a matter of furprife to me, that moft or all of
my effays publifhed in the volume above mentioned, have been -
copied and circulated in one or other of our periodical publi-
cations, except thofe two juft mentioned, which appear to me
by far the moft important, and which feem too to have been
confidered as fuch by the forcign journalitts.
Iam your’s, &c.
: J. DALTON.
Manchefter, Aug. 22, 1803.
Xi.
Cheap and effectual Method of fecuring Beams of Timber in H oufes
or elfewhere, which have been injured by the Dry Rot, or are
decayed by Teme. By Mr, James Woart.*
W urre the ends of the girder are: decayed by time, or
injured by the dry rot, they are often taken out, and new
onés put in their place, at a great expenfe: and if the dry rot
is in the walls, the ends of the new girder will be in danger se
of it again: fuch was the cafe at Eliham, in Kent, where in
one hotife there were three new girders to one floor in the fpace
of twenty years ; whereas my method will be found infallible,
executed at much lefs expence, and not fubjeét to the dry rot,
becaufe the end of the girder may be cut off clear from the
wall; and if an air grate is put on the outfide, fo as to admit
air to the end of the girder, it will remain fafe from injury.
Plate 1X. Fig, 2.t-—A, fhews the end of the decayed girder,
with the braces applied upon it.
. BB,
* Memoirs of the Society of Arts, 1802. A reward of twenty
guineas was awarded to the inventor, who, in an introduétory let-
ter ftates, that by the iron braces, of tefs coft than 20]. he fecured
the houfe of Hannege Legg, Efq. at Putney in Surry, which could
not have been done by new beams without lofs, derangement, and .
sharges to the amount of eight hundred pounds.
+ There are two plates i in the Tranfactions, the fecond of which
forms
METHOD OF SECURING DECAYED TIMBERS. 1}
BB, the templets or wall-plates on which the girder refts. Eafy method of
CCCC, one of the iron levers for raifing and fupporting Spirria ingle hy
the girder (there being a fimilar one on the oppofite fide.) ings, gc.
This lever is moveable on a pin D, which comes through a
hole in the lever, diftant about two feet from the end of the
girder.. This pin forms part of a collar E bedded in the girder.
The lever is fix feet long, three inches wide, and three fourths
of an inch thick, and extends from the wall-plate along the
fide of the girder.
The extremity of the lever is moveable on another pin F;
projecting through it from an upright iron G, bedded in the
fide of the girder, and carrying a nut and fcrew, which aé&
on acrofs plate H, through which the upright iron paffes.
At the other end of the lever, next the templet, is an iron
collar I, bedded in the girder, which collar may be raifed or
Jowered at pleafure, by means of the nut and fcrew K, form-
ing part of it; and by aid of the cap-plate L, which preffes
upon the lever, and alfo clafps it to the girder by its bend at L.
As Plate 1X. Fig. 2, fhows only one fide of the girder, and,
as has been before obferved, there being alfo a finular lever
on the oppofite fide of the girder, their feparate parts, method
of conneéting them, and their mode of aétion, are more fully
explained in Plate VII. Fig. 1, 2, 3, where the fame letters
are made ufe of to point out the feveral parts.
Fig. 1.—E, thows the whole of the collar to be bedded in
the fide and bottom of the girder, and the pins D D, on which
the two levers are moveable. :
Fig. 2.——The cap-plate H, the two upright irons G G, with
their nuts and fcrews, which aét upon the extremities of the
two levers by means of their pins F F.
Fig. 3.—The collar I, on which that end of the girder next
the templet refts, the fides of which collar are bedded in the
girder. CC are the claws or bended legs of the two levers.
_ which go into the templet. Lis the cap-plate, K K are the
nuts and fcrews.
At Mr. Legg’s houfe, where the levers above eb
were applied, the beams of the roof were fo decayed that the
roof was in imminent danger, the bearings were entirely rot-
forms Plate VII. of our prefent number. The other unfortunately
was neglected to be fent to the engraver’s, and the miftake not dif-
covered till too late. It will be given in our next,
ten,
122 METHOD OF SECURING DECAYED TIMBERS,
Eafy method of ten, and the beams were funk three fourths of an inch, and
fecuring decayed prefling againft the wall for fupport ; if there had not beena
timbers in build- : ;
ings, &ce large cornice underneath, fupported by brackets, the whole
roof muft have fallen.
To put them in order, I firft put fhores or fupports under
each end of the two beams, on which the double roof lay,
and then forced the four fhores at once, for the fecurity of the
roof, the work, and men. The iron levers, C, were then
prepared, let into the templet, and fixed on each fide of the
beam, on the pins D, projeéting from the collar E, bedded in
the beam, about two feet from itsend. When the whole ap-
paratus was ready, on {crewing the nuts on the upright irons
G, at the extremity of the levers, the beam was raifed to its
proper height with great eafe, although it was fuppofed there
was above two tons weight on each beam, on account of the
lead gutter, and gutter-beam betwixt the double roof, and the
rich ornamented ceiling attached to the joift, which was notin
the leaft deftroyed except where the iron collar E was fixed,
which was put up from the under fide by cutting the ceiling the
width of the collar. Thefe beams were fo decayed, and fo
hollow, that the common method of bolting plank on each fide
of the beam would not have been fafe; and if it could have
been executed, thenew planks would have been fubje& to the
dry rot, and the roof ftill in danger, which is now prevented,
as the iron is not affected by it. The beam-ends were cut
clear from the walls, and the beams are fufpended by means
of the iron levers, whofe feet reft on the templets of the walls.
An air grate was made, on the outfide of the wall, to admit a.
current of frefh air to the ends of the timbers. The roof is
now much fafer than when originally made, as the timber is
fecured from decay ; and, owing to the collar E, the bearings
are now two feet fhorter at each end of the beam ; the bearing
on each beam being now, in the whole, four feet fhorter than
in its original ftate. |
After ,the beams were brought to their proper height, and
the levers and ferews adjufted, fcrew-bolts were put into the
timber, through holes purpofely left in the lever, betwixt D
and F, and the whole work thus perfeétly fecured.
At the other end of the girder, M, Plate IX. is fhown an-
other method of fupporting timbers, where the ends are de-
cayed.
The
METHOD OF SECURING DECAYED TIMBERS, 193
__» The particular irons ufed in this way are thown in Plate VII. Eafy method of
Fig. 4. N is-a collar for the girder ; O, aniron frame which gracias pce ti
refts on the templet; P P, two nuts which raife the collar N. ings, &Ce
R R fhow the clawed ends of the two bars of iron,. extending
under the girder, bedded. therein, and fcrewed to it at their
extremities, about five feet diftant from the templet.
Fig..5, is one of the iron bars laft mentioned.
S is the claw or lap which projeéts over the collar N. T is
the place where it is {crewed into the girder.
Fig. 6 and 7. Plate VII. explain a third method of fecuring
decayed timbers.
Fig. 6, gives a fide view of a decayed girder: a, reprefents
the templet; 5b, an iron lever, fix feet long, nearly- ftrait,
being only cambered one inch, three inches wide, and three
quarters of an inch thick ; this lever-extends along the fide of
the girder c, and is fecured firmly toit by the fide irons d dd d,
which are two ‘inches wide, and full half an inch thick, point-
edat the ends. The higher ends of thefe fide irons are driven
into the girder, and the lower points pafs through holes in the
lever into the lower part of the girder, and are held clofe to
the girder by ftaples eeee: the fide iron next the templet
may be fixed flanting, in order that it may enter founder wood.
A claw, f, which is part of the lever, refts on the wall plate
a, and is bedded in it ; an iron plate, g, lying under the girder,
_ and let into it, paffes through the lever at 1, conneéting it
with a fimilar lever on the oppofite fide, and which affiits in
the fame way to fupport the girder: 7 isa flooring joift, to
fhow how deep the levers are inferted therein.
Fig. 7, thows the under part of the fame girder; bb, are
the bottoms of the two levers above mentioned, fixed to the
girder by the fide irons and ftaples before defcribed; kk, the
broad feet of the levers which lie flat upon the wall plate; ff
the two claws projecting from the feet, in order to bed in the
wall plate ; 7277 are joifts, partly cut through, to admit the
iron levers to lie clofe to the girder: g thows the iron plate or
collar on which the girder bears; it is tarnéd up an inch anda
half at each end, to keep the levers clofe to the fides of the
girder. This collar fhould be made out of inch-bar iron, with
points projecting from it, in the fame manner as the collar at
DD, Fg. 1, to conneét it with the levers, by paffing through
holes made through them for that purpofe.
— To
124
Introductory
ubfervations on
ebe ufelefs trees
“in orchards.
BRANCH GRAFTING.
To fix the levers, put a fhore two feet fix inches from the
wall, under the girder, to fupport it ; then cut off the decayed
end, and take out the templet, or part of the wall plaie, if
decayed ; and put in a ftone templet for the irons to reft upon,
with mortices in the ftone to admit the claws of the lever : then
fit the collar underneath the girder, two feet from the wall,
to anfwer the holes in the lever ; make an incifion in the joifts
three-fourths of an inch wide, and three inches deep, to
admit the levers; fix the levers on each fide with the collar,
fo as to force up the. levers together; then with flight
fhores force up the ends of both levers together, and fix the
fide-irons firm. The girder will thus be perfeétly fate.
The templet or wall plates, on which the levers reft, are
made of Portland ftone, three feet long, nine inches wide,
and five inches deep, with incifions or mortices made therein
for the claws of the levers. ;
_ Certificates, confirming Mr. Woart’s improvements, were
received from the commillioners of the navy, from Mr. Jofeph
Harris, fmith, at Putney, and Mr. George Smith, furveyor,
at Putney.
XIII.
Account of the Method of extreme Branch. Grafting. By the
Inventor Witt1amM Fatrman, Ly/q.*
STR);
From much converfation with Mr. Bucknall on the idea of
improving ftandard fruit-trees, we could not but remark that
in apple orchards, even in fuch as are moft valuable, fome
were to be feen that were ftinted and barren, which not only
occafioned a lofs in the produétion, but made a break in the
rows, and fpoiled the beauty and uniformity of the planta
tion,
To bring thefe trees into an equal ftate of bearing, fize,
and appearance, in a fhort time, is an objeét of the gréateft
importance in the fyftem of orcharding, and alfo for the
* In a letter to Charles Taylor, Efq. Secretary to the Society
of Arts, and inferted in their Memoirs for 1802. For which the
filver medal was awarded.
recovery
BRANCH GRAFTING. 125
recovery of old barren trees, which are fallen into decay, not
“fo much from age, .as from the forts of their fruits being of the
worn-out and deemed nearly loft varieties.
Having long entertained thefe thoughts, and been by no
means inattentive to the accomplifhment of the defign, I ate
tempted to change their fruits by a new mode of engrafting,
and am bold enough to affert that I have mioft fortunately New method of
fucceeded in my experiments; working, if I am to be allowed &ti"é+
_to fay it, from the errors of other practitioners, as alfo from
thofe of my own habits.
My name having feveral times appeared in the Tranfactions
of the Society for the Encouragement of Arts, &c. and having
the honour of being a member of that Society, I thought no
pains or expence would be too much for the completion of
fo defirable an improvement. Under thefe impreffions, and
having many trees of this defcription, I made an experiment
on three of them in March 1798, each being nearly a hundred
years old. They were not decayed in their bodies, and but
Jittle in their branches: Two of thefe were golden pippins,
and the other was a golden rennet. Each likewife had been
paft a bearing ftate for feveral years. I alfo followed up the
_ praétice on many more the fucceeding fpring, and that of the
taft year, to the number of forty at leaft, in my different
plantations *. '
The attempt has gone fo far beyond my moft fanguine exe
pectation, that I beg of you, Sir, to introduce the fyftem to
the Society, for their approbation ; and I hope it will deferve
the honour ofa place in their valuable Tranfaétions,
I direéted the procefs to be conduéted as follows: Cut out Inftru@ions for
all the (pray wood, and make the tree a perfe@t tkeleton, leav- PR PonNs ste
ing all the healthy limbs; then clean the branches, and cut
the top of each branch off where it would meafure in circum-
ference from the fize of a fhilling to about that of a crown
-piece. Some of the branches muft of courfe be taken off
where it is a little larger, and fome f{maller, to preferve the
canopy or head of the tree; and it will be neceflary to take out
the branches which crofs others, and obferve the arms are left
to fork off, fo that no confiderable opening is to be perceived
when you ftand under the tree, but that they may reprefent an
.@ The average expence I calculated at 2s. 6d. each tree.
2 uniform
126
Pofition of the
rafts.
Cement and
general prepara-
tionand ma-
hagement.
Great advane
tages of leaving
the tree of its
full fize.
—and increafing
its powers.
BRANCH GRAFTING.
uniform head. I muft here remark to the praétitioner, when
he is preparing the tree as I direéted, that he fhould leave the
branches fufficiently long to allow of two or three inches to be
taken off by the faw, that all the fplintered parts may be
removed. .
The trees being thus prepared, put in one or two grafts at
the extremity of each branch ; and ‘from this circumftance I
with to have the method called extreme branch grafting.
A cement, hereafter defcribed, muft be ufed inftead of clay,
and the grafts tied with bafs or foft ftrings. As there was a
confiderable quantity of mofs on the bodies and branches of the
trees, I ordered my gardener to fcrape it off, which is
effe@tually done when they are in a wet ftate by a ftubbed
birch broom. I then ordered him to brufh them over with
coarfe oil, which invigorated the growth of the tree, aéted as ~
a manure to the bark, and made it expand very evidently ;
the old cracks were foon, by this operation, rendered in-
vifible.
All wounds fhould be perfe@ly cleaned out, and the medica-
tion applied as defcribed in the Orchardift, p. 14. By the
beginning of July the bandages were cut, and the fhoots from
the grafts fhortened, to prevent them from blowing out. I
mutt here, too, obferve, that all the fhoots or fuckers from the
tree muft enjoy the full liberty of growth, till the fucceeding
fpring, when the greater part muft be taken out, and few but
the grafts fuffered to remain, except on a branch where the
grafis have not taken: in that cafe, leave one or more of the
fuckers, which will take a graft the fecond year, and make
good the deficiency. This was the whole of the procefs *.
By obferving what is here ftated, it will appear that the
tree remains nearly as large when the operation is finifhed, as
it was before the bufinefs was undertaken ; and this is a moft
effential circumftance, as no part of the former vegetation is
loft, which is in health fit to continue for forming the new
tree.
It is worthy of notice, that when the vivifying rays of the
fun have caufed the fap to flow, thefe grafts inducing the fluid.
through the pores to every part of the tree, will occafion in-
* The fyftem fucceeds equally well on pear, as alfo on cherry
trees, provided the medication is ufed to prevent the cherry’ tree
from gumming.
numerable
BRANCH GRAFTING.’ 127
numerable fuckers or {cions to ftart through the bark, which,
together with the grafts, give fuch energy to vegetation, that
in the courfe of the fummer the tree will be a€tually covered
ever by a thick foliage, which enforces and quickens the due
circulation of fap. Thefe, when combined, fully compel the
roots to work for the general benefit of the tree.
In thefe experiments I judged it proper to make choice of The mot luxu-
grafts from the forts of fruits which were the moft luxuriant in halt Pe
their growth, or any new variety, as defcribed in the feven-
teenth and eighteenth volumes of the Society’s Tranfaétions,.
by which means a greater vigour was excited; and if this
obfervation is attended to, the pratitioner will clearly perceive,
from the firft year’s growth, that the grafts would foon ftarve
the fuckers which fhoot forth below them, if they were fuffered
to remain*. With a view to accomplifh this grand objeé of
improvement, I gave much attention, as I have before obferved,
to the general praétice of invigorating old trees ; and I happily
difcovered the error ofthe common mode of engrafting but a fhort
diftance from the trunk or body, as in Fig. 1. Pl. VIII. There
the circumference of the wounds isas large as to require feveral
grafts which cannot firmly unite and clafp over the ftumps,
and confequently thefe wounds lay a foundation for after-
decay. If that were not the cafe, yet it fo reduces the fize
of the tree, that it could not recover its former ftate in many
years, and it is dubious if it ever would; whereas, by the
method of extreme grafting, as Fig. 3, the tree will be larger,
in three or four years, than before os operdeiee was performed. |
For all the large branches remaining, the tree has nothing to
make but fruit bearing wood ; and from the beautiful verdure
it foon acquires, and the fymmetry of the tree, no argument
is neeeffary to enferce the praétice.
Fig. 2 was my firft experiment about eight years fince. The
error of No, I was there a little amended, and gave me the
idea of engrafting at the extremity. Permit me to remark,
_ that thofe done in my orchards, on the plan of Fig. 2, did .
not, neither were they able to bear fo many apples laft feafon,
which was a bearing year, as thofe on the plan of Fig. 3
* This thought fhould be kept in fufpence, as ten years hence
it may appear otherwife. However, they will be valuable trees,
and highly profitable, as will any other brought under the fare
oo
which
128 BRANCH GRAFTING.
which produced me about two bufhels each tree of the fineft
fruit I had in my orchards, from the third fummer’s wood only.
Some engrafted with Ribfton pippins were beautiful.
Approbation of | Mr. Bucknall vifited me this fummer for the exprefs purpofe,
Mr. Bucknalle of feeing my trees; and he fays the manner of conduéting the —
fyftem is the happieft that ever was conceived. For when a
tree has done its beft, and has continued to extreme oldage,
juft difpofed to fall into diffplution, as alfo when this is the
cafe with trees in a ftagnated and barren ftate, they are thus
renovated, and may, with; the greateft probability, continue
valuable for fifty years to come. Ineed not fay, do not make
the attempt when the energy of growth is over; that will
eafily be feen by the body and arms, but more particularly
from the fize, figure, fhape, and colour of the leaves, which
give the proper indication of health or decay in vegetation.
Should the Society defire it, feveral gentlemen refident
here, will gladly fend up certificates to confirm the ftatee
ments.
I remain, Srr,
Your moft obedient fervant,
W. FAIRMAN,
Millers-Houfe near Sittingbourn, Kent,
Feb. 9, 1802.
CEMENT FOR ENGKAFTING.
Cement for § One pound of pitch
engraftinge © One do.... rofin To be boiled up together, but.
Half do... . beefwax not to be ufed till you can bear
Qtr. do.... hogflard your finger in it.
Qir. do... .. turpentine
SIR,
Teftimonial of “THIS is to certify to the Society for the Encouragement of
Bi. Bucknall, Arts, &c. that William Fairman, of Millers-Houfe, Lynfted,
Efq. has long been a fteady and zealous promoter of the im-<
provement of the ftandard fruits of the country ; and that he
planted one entire orchard, of fixteen acres, ten years ago.
The fyftem of extreme-branch grafting, now intkoduced to
the public, he has had in contemplation full eight years,
though not in its prefent ftyle of fuccefs and elegance; for he
has been improving. In thofe operated upon within the laft
| thre
BRANCH GRAFTING. | 129
three or four years he has been wonderfully fuccefsful, and I
am happy in an opportunity of adding my teftimony to the
advantages refulting from this methad of renovating old fruite
trees.
An idea equal to the prefent fyftem could not have fallen
into better hands than thofe of Mr. Fairman. He is bleffed
with a good foil, cultivates the land well, and fteadily attends
to improvement; The gentlemen of the committee, by looking
at the three little fketches of drawings which reprefent the
three trees, will fee that Fig. 1 is fo amputated, as not likely
to continue in health, foas again to form a good tree; and
that Fig. 2 will be many years before, if ever it does. But
there are now many fine large trees in the ftate of Fig. 3,
which have been engrafted but three or four years, and yet, ~
as far as ftru€ture goes, are complete already, and in two
years much fine fruit may be expeéted.
The fyftem is as follows: Make the trees perfeétly clean,
and keep them as uniformly large as is convenient.
In autumn, 1801, I fpent fome days at Lynfted, and feveral
times walked over the plantations with Mr. Fairman, and was
very much pleafed with their appearance,
I remain, Srr,
Your obedient Servant,
THOMAS SKIP DYOT BUCKNALL,
February 22, 1802.
Reference to the Engraving of Mr. Fatrman’s Method of — Reference to'thé
Extreme-Branch Grafting; Plate VU. Fig. 1, 2, 3, 4. a
Figure 1. difplays the old pra@tice, commonly called clefts
grafting.
. Fig. 2. Improved experiment on Fig. 1, by engrafting
higher up the tree.
Fig. 3. Shows the method of extreme-branch grafting, rea
commended from experience, by Mr. Fairman. Two grafis
or fcions are there placed at the extremity of each branch ;
befides which, additional grafis are inferted in the fides of the
branches; as, at AAAAAA, or where they are wanted to
form the tree into a handfome fhape.
Fig. 4, Shows upon a larger feale than the former figures
the method of applying the grafts at the extremity of the
_ branches, and retaining them by the bafs-mat bandage and
cement.
Vor. Vi—Octoser, 1803, K Obfervations
13e
Unguentum
nutritum.
The mixture of
oil, vinegar,
and litharge.
Requires car=
bonic acid,
#o convert the
litharge into
caibonate,
and thicken the
oil.
Too much vine-
gar will pre
vent the com-
bination. '
Dhe formula of
the French
pharmacupeia
the beft.
Litharge com-
pletely foluble
in acetous acid,
but not in com-~
mon vinegar.
The refiduum
of the latter.
FHARMACEUTICAL PREPARATIONS.
XIV.
Objercatious on feveral Pharmaceutical Preparations, by Crrs.
STEINACHER, Druggift at Paris. Abridged by Citizen
PARMENTIER*®,
Unguentum Nutritum.
Citizen Dubree, an eminent druggift at Rouen, has
lately prefented a formula for unguentum nutritum, to the
Pharmaceutical Society. As apothecaries zealous for the per=
feétion of their art, have propofed improvements in the pre~
paration of this ointment at different periods, I have thought
that an objeét to which the attention of praétitioners has been
called from time to time, notwithftanding it is apparently ob-
folete, deferved a frefh examination +.
When oil, vinegar, and litharge are to be mixed together
into a homogeneous mafs, alittle IMharge mutt be diffolved in
acetous acid t, and a fufficient quantity of carbonic acid muft
he introduced, 1{t, to convert the greater part of the litharge
into white carbonate, which remains diffufed through the oil;
Qdly, to thicken the oleous mixture, an effeét analogous to the
thickening of foups by the carbonic acid, with which we were
made acquainted by Pelletier. If a fufficient quantity of
vinegar to form a faturated faline compound be employed, the
mixture will never combine perfe@tly. This theory, founded
on experiment, brings us back to the prefcribed formula, as the
beft ihat can be adopted, that which preduces an ointment,
the moft bulky, the lighteft, and the moft cooling to the part
* Annales de Chimie, XLVII. 97. (No. 139.)
+ Dr. Aikin, the learned editor of Lewis’s Materia Medica,
fays; “* The unguentum nutritum, made without heat, though now
expunged from our difpenfatories, is much the beft of the ointments
prepared from lead, and a very excellent application in many cafes.
It fhould not be long kept, but made frefh as wanted.” H.
t Experience has taught me, that levigated litharge is completely
foluble in a fufficient quantity of acetous acid, but that the final re~
‘fiduum of its folution in common vinegar, which has been fuppofed
to be fuperoxided lead, contains only tartrite and malat of lead, with
a great deal of extraétive matter, which form a pafte with a remnant
of the litharge reduced toward the metallic ftate-
affected,
PHARMACEUTICAL PREPARATIONS. 131
affééted. It fucceeds very well, when the operator is endued
with patience, and worksina cold place. It may be abridged The procefs may
however, if, according to the excellent advice of Baumé, we ae eh i
employ coagulated oil of olives, by which the furfaces of con- gulated oils
taét are increafed, and the introdu@tion of the air is facilitated.
One important faét with refpeét to keeping the preparation is, Warmth fpoils
that at the temperature of 15° or 16°, at which moft kinds '*
of fermentation take place, a portion of the carbonic acid is
extricated, and leaves expofed an oxide at +25, which becomes
again yellow. It requires a temperature of 10° to preferve But it will keep
its white colour unaltered. sinless
Citizen Dubree, and Citizen Granet before him, propofed ne ee of
to expedite the preparation by adding hog’s lard; but I find, a aaie rans
_ that this addition diminifhes its bulk and Lets In Germany D: biaaie aN
different compofitions are made under the name of nutritum, POTS os
as with vinegar of litharge and half its weight of oil of rofes, Germany«
which peadune an ointment as white as wax, and of the con-
fiftence of aliniment; with vinegar of litharge two parts, and
olive oil three parts, itch Giicka a whitifh ointment of a mo- .
derate confiftence; with two parts of olive oil, one part of
wax, and two parts of vinegar of litharges; which furnifh an
Ointment of a firm confiftence, and a waxy whitenefs. But all All thefe fimply
thefe compofitions are fimple mixtures, feebly united, by no ™*™***
means refembling the nutritum of the French fhops, and not
requiring for thelr formation a mutual reaétion between the dif-
ferent particles of the ingredients.
Cryftallization of Phofphoric Acid.
It is known, that the affinity of phofphoric acid for water Phofphorie acid
_ overpowers its force of cryftallization; in faét this falifiant fub- ane aed:
ftance appears commonly in the form of a thick oil. I have yet cry ftalliz=
lately obferved, however, that time, the grand producer of ble by time.
regular cryftallizations, effeéts a fymmetrical combination be-
tween its particles.
Thad prepared halfa kilogramme of phofphoric acid, accord-
ing to the method of Lavoifier; with phofphorus and nitric
atid, both of them extremely pure. This acid, freed from
nitrous gas, reduced to the confiftence of a thick fyrup, and
introduced into a phial with a glafs ftopper, had been ufed at
different times in the courfe of a year, without exhibiting any
peculiar appearance, The year following I let it remain per-Cryftals formed
‘aaes K 2 feétly in it by repofey
132 PHARMACEUTICAL PREPARATIONS. -
feétly at reft in the phial, which was half full, and clofely
Thefe cryfials flopped. After this period I found the furface of the fluid
eet Mi ese covered with a faline cruft, from which thot downward prif-
famine. matic cryftals in fhining laminz, an inch long, and a line broad,
diverging from acentre. I will not defcribe their geometrical
ftru€ture, for they are extremely thin, and embedded ina fluid
too vifcous for me to take them out without breaking. Befides,
they are ftill increafing ; laminze rife from the ealtnns of the
veflel, which touch the furface of the glafs, and feem pre-
paring to intermix with the ramifications that fhoot down from
the upper ftratum. The fides of the veffel are the feat of this
beautiful cryftallization. The centre remains in part concrete
or fluid, whenceit follows, that if a very regular diffipation
of the particles of the liquid acid of phofphorus be occafioned
by repofe, the fides of the veffel contribute to it in great mea-
fure by affording fixed points, to which the pofitions of affinity
moft favourable to cryftallization dire& themfelves.
Purity of Phofphorus.
Charcoalcom- Prouft has informed the public, that, in the diftillation of
bines with phof- phofphorus, a combination of this fubftance with the charcoal
phorus daring
the diftillation, conftantly took place. This important difcovery, extends much
farther than its celebrated author has fhewn.
Phofphorus pu» Take the moft brilliant and moft tranfparent phofphorus,.
caer which has not only been ftrained through chamois leather, ac-
method. cording to Woulfe’s method, but has alfo been diffolved feveral
Muffin. Pufch- times in nitro-muriatic acid, as done by Count Muffin-Pufchkin,
eee or which has been treated with oxigenated muriatic acid, after
or Juch’s, the mode of Mr. Juch of Wurkburg ; let it be heated gently
‘fill thewsmarks in a long flender tube; red parts will feparate from it. Puta
ig few grains of this phofphorus, which is conceived to be fo
pure, ona filver fpoon, and fet fire to it; a red trace will re-
main. If the fpoon be heated in the dark, the red trace will
be feen ftill to burn, and a coal will remain impregnated with’
phofphoric acid.
Heatingwith Mr. Juch has afferted, that his phofphorus is extremely,
ee pure, becaufe it no longer becomes black when heated with.
proving the pu- cauftic alkali; but it isin fa&t becaufe the phofphure of car-
po of phofpho- hone is unalterable by cauftic potath. According to the indifput-
able authority of Prouft, this re-agent is incapable of proving
Heatedoxige- the purity of phofphorus, I confels, that heated oxigenated
nated muriatic muriatie
ee rc ee ——t—(CSCt—™S
e ,
PHARMACEUTICAL PREPARATIONS, 133
muriatic acid deftroys part of the carbone of phofphorus, be- acid deftroys
caufe the combuftible power of its oxigen increafes in the P@rt of the care
ratio of its elafticity ; but it produces this effect only by burn-
ing a proportionate quantity of phofphorus. On the contrary, Cold feparates
when it is cold, and its oxigen is reduced to its natural degree a of
of elafticity, it is far from deftroying the carbone, it feparates rer
it in the ftate of black oxide, and converts the phofphorus inte
white oxide, while at the fame time, itfelf returns to the ftate
of fimple muriatic acid. Ihave obferved this fa@ on a ftick
of tranfparent phofphorus, which I kept two years in a bottle
filled with pure oxigenated muriatic acid, faturatéed at the tem-
perature of 10°. It is impoflible, therefore, ‘to free the phof- Impoffible to
phorus entirely of charcoal. They oxide, or are acidified nearly {°° Phof horus
e i ee ‘ 4 from charcoa)
in proportional quantities ; and though the proportion of char- completely.
_ Coal may be diminifhed, the phofphorus always retains fome by
Hs power asa whole. In fine, I am obliged to contradi@ the
affertion of an illuftrious mafter, Citizen Fourcroy, ‘* that we Miftake of
are unacquainted with any dire&t combination between car- Fovrcroys
bone and phofphorus, though it probably exifts,” and to cone
fider that produét on which chemifts have hitherto beftowed
the name of pure phofphorus, as'a kind of gangue, from which Pare phofphorus
the radical phofphorus is difengaged to enter into a number of ¥°t bakaowne
combinations, without our being capable of obtainmg it in its
primitive form,
White Oxide of Phofphorus.
When phofphorus is heated in a very long and very Mode of cin-
flender glafs tube, in a fand-heat of 100° of the decimal ther- ae ona
mometer, it is covered with a mild light, and exhales a white white oxide at a
vapour, which condenfes in the upper part of the tube, while, ™#!mum.
at the fame time, part of the phofphorus, with excefs of
carbone, feparates with its red colour. This white vapour,
which has acquired for its formation a flight combuftion, is a
white oxide of phofphorus ata minimum. The following are
fome of its properties. It is flocculent, poffeffed of cohefion, some of its pros
and occupies four times the {pace of the phofphorus employ ei perties.
in the experiment. When it is dry, it does not redden lit-
mus paper. It contains caloric, and inflames on the conta¢t
of combuftible fubflances. It powerfully attraéts the moifture
of the air, and is rapidly converted into phofphorus acid. It White oxide of
differs greatly from the white oxide of phofphorus made Fe a ‘i
Bile 1
134 SCIENTIFIC NEMS.
Its properties, the long a€tion of water, or cold oxigenated muriatic acid.
This appears friable and pulverulent. It has loft almoft all
its Jatent heat. It is very little inflammable, and does not
attract the moifture of the air. It is acidifiable only by the
intimate action of an oxigen that contains caloric highly con-
denfed, as that of the nitric acid. Ina word, it is phofphorus
at a maximum of oxidation.
Regular Cryfiallization of Effential Oil of Rofes.
Regular cryftal- Citizen Steinacher has lately obferved this with atten-
eas oilof ‘tion, He mixed eight kilogrammes of the magna of da-
mafk rofes (rofés pales) with {ome parts of water, according
to the procefs of Cit. Demachy; and after a day’s macera-
tion he drew off by diftillation fixteen kilogrammes of water.
This was immediately poured into a large glafs jar, which was
covered with a cloth, and left at reft. In twenty-four hours
he found the furface of the water covered with an iridefcent
Refembles the pellicle, interfperfed with little hexhaedrons, very much re-
cryftalsof fnow, fembling the cryfials of {now, which the illuftrious Cit.
Mongé has defcribed. He informs us, that a flight fhake is
and requires ab- fufficient to tear the cryftalline gauze, and reduce it to that
folute repofes irregular form of whitifh fcales or lamin, which the oil of
rofes commonly aflumes.
——_—_—_—_$_ =_[_[_[_$_=====—[—[—[—[—[—=&=£_=[—[F—[—[—*—T———————[——————SSS>SS—
SCIENTIFIC NEWS.
Extra& of a Letter from Dr. Scuaus to Mr, Parkinson,
dated Caffel, july 2, 1803.
I AM bufily employed in the analyfis of various minerals, ©
the refults of which I fhall communicate to you in my next.
I have noticed among other things alfo, that the metal called
Tungften not tungften (Wolfram by the Germans) can only be obtained at
co the higheft degree of de-oxidation, and that this metal does
not belong to the clafs of acidifiable metals ; for tungflen
cannot be oxidized by means of common proceffes of oxida-.
New method of yen. :
obtaining pure 1 have difcovered a new method of obtaining pruffic acid, in
pruflic acid. a ftate of abfolute purity. This procefs confifts in pouring upon
one part of pruffian blue, half a part of fulphuric acid, diluted
3 with
SCIENTIFIC NEWS. ; 138
with an equal quantity of water, and fubfequent diftillation,
The pruffic acid paffes over in the alcohol; its odour greatly
refembles the water of the lauro cerafus.
It is a deadly poifon to animals. Perhaps thefe notices ee
intereft the London chemifts, &c. &e.
Annotation by the Tranflator,
The following method of obtaining tungften, I believe has Richter’s_
not been made known in this country. It is recommended by opamp rom
Richter * a German chemift.—F. A. he SE
Let equal parts of tungften oxide (tungftic acid) and dried
hlood be expofed for fome time to a red-heat in a crucible ;
pafs the black powder which is formed into another findttet
crucible, and expofe it again to a violent heat ina forge, for
at leaft an hour. Tungften will then be found, according ta
this chemift, in its metallic ftate in the crucible.
See
Meteoric Stones,
C. BIOT, member of the National Inftitute, in a letter to the Extraordinary
French Minifter of the Interior, dated July 20, 1803, gives a Aideos or til
‘detailed account of his inquiries, &c. refpe@ting a fire ball in France.
which exploded in the neighbourhood of Laigle. The memoir
will be feparately printed.
On Tuefday, April 26; 1802, about one in the afternoon,
the weather being ferene, there was obferved from Caen,
Pont-Audemer, ie the environs of Alencon, Falaile, and
Verneuil, a fiery globe of a very brilliant {plendour, which
moved in the atmofphere with great rapidity.”
Some moments afier there was heard at Laigle, and in the
environs of that city in the extent of more than thirty leagues
in every dire¢tion, a violent explofion, which lafted five or fix
minutes.
At firft there were three or four reports like thofe of a cannon,
followed by akind of difcharge which refembled a firing of
‘mufketry ; after which there was heard a dreadful rumbling,
like the beating of a drum. The air was calm and the fky-
ferene, except a few clouds, fuch as are frequently obferved.
* Richter ueber die neuen gegenftande der Chimie, Part I. p. 49.
Nu ' : , - A The
13¢
SCIENTIFIC NEWS.
The noife proceeded from a {mall cloud which had a: reét~
angular form, the largeft fide being in a direétion from eaft to
weft. It appeared motionlefs all the time that the phenome~
non lafted. But the vapour of which it was compofed was
projeGted momentarily from the different fides by the effeét of
the fucceffive explofions. This cloud was about half a league
to the north-north-eaft of the town of Laigle; it was at a
great elevation in the atmofphere, for the inhabitants of two
hamlets a league diftant from each other faw it at the fame
time above their heads. In the whole canton over which this
cloud hovered, a hiffing noife like that of a ftone difcharged
from a fling was heard, and a multitude of mineral maffes,
exaétly fimilar to thofe diftinguithed by the name of meteoric
tones, were feen to fall at the fame time.
The diftriét in which the ftones fell forms an n elliptical extent
of about two leagues and a half in length and nearly one in.
breadth, the greateft dimenfion being in a dire@tion from
fouth-eaft to north-weft, forming-a declination of about 22°.
This dire@ion which the meteor muft have followed is exadly
that of the magnetic meridian; which is a remarkable refult.
The largeft of thefe ftones fell at the fouth-eaft extremity of
the large axis of the ellipfe; the middle-fized ones fell in the
centre, and the fmalleft at the other extremity. It thereby
appears that the largeft fell firft, as might naturally be fup-
pofed.
The largeft of all thofe which fell weigh 172 pounds. The
{malleft he faw weighed about two gros, which is the thous
fandth part of the former. The number that fell is certainly.
above two or three thoufand. They were friable fome days
after their fall, and fmelled ftrongly of fulphur. Their prefent
hardnefs was acquired gradually.
(ee
gee: of a Memoir on the Febrifuge Principle of Cinchona,
by Crt. Securn *,
~ ‘THE objeét propofed to himfelf by the author in the tafk
he undertook was, to point out the means of knowing with
certainty the. true febrifuge principle of cinchona, to dif-
tinguith the fpecies that contain it from thofe that da not, and’
laftly to appreciate its quantity and quality.
* Bulletin des Sciences, No» 7% :
Hitherto.
SCIENTIFIC NEWS. 137
Hitherto the fight and tafte have been the only tefts of the Sight and tate
prefumable qualities of the peruvian bark of the thops; but as nae Gene
thefe bave no precife ftandard, and are inapplicable: to goodnefsof bark.
powdered bark, they-very imperfe@tly indicate the prefence
of the febrifuge principle. It was of importance, therefore,
to fubftitute to thefe means, little better than illufory, others
not only capable of calculation, but likewife invariable. Che-
mical re-agents alone can anfwer thefe ends,
In. confequence Cit. Seguin began by ifolating the refpe€tive
properties of all medicinal fubftances, and he examined the
action they exert on all other chemical fubftances.
Thefe refearches led him to develope very decifive chara€ters The febrifuge
eftics in the febrifuge principle of cinchona; which place it rie.
ina perfeétly diftinét clafs. The following are its chara€ters.
It precipitates the folution of ian, but not the folutions of Its charaéters.
gelatine and fulphate of iron.
When cinchona has not all thefe charaéters, it is a proof
that it is mixed with fomething elfey or that it does not contain
the febrifuge principle.
The author has fubje@ed to this analyfis all the known Various fpeci-
fpecies of cinchona, found among all the druggifts and apothe- eee
caries of Paris and Verfailles, and conftantly obtained the tett,
fame refults.
Unfortunately thefe refearches have fhown, that but an Ba ee
infinitely {mall quantity of good, unmixed cinchona, is ta be good is to be
procured in the fhops; the greater part being either deftitute Sy in the
of the febrifuge principle, or mixed, or of a very inferior on
quality, though containing no mixture. }
_ Thefe refults are of fo much the greater importance, be- Efficacy of cine
caufe the effects.of different kinds of cinchona in fevers are Sapo bee
only in proportion to the greater or Jefs quantity of the febri- quantity of fe-
fuge principle they contain; and thofe which contain none, as napa lage. .
well as all the fubflances that may be mixed with them, are
more or lefs injurious to the fyftem.
The experiments of Cit, Seguin on. the febrifuge stindiple Defeéts rd ee :
of cinchona, having convinced him that moft: of the bark found oe tee .
in. the fhops was injurious or inefficacious, becaufe it was {poiled
by keeping, adulterated by mixture, or deprived of the febri-
fuge principle ; he has endeavoured to obtain a febrifuge prin-
ciple always the fame, more efficacious, more certain in its
effe&s, more capable of affimilation with our fyftem, and: fo
cheap, that there could be no temptation to adulterate it.
ii 5 To
138 SCIENTIVEO NEWs.
To attain this important objeét, the author has inquired what
aS the true caufe of fevers, as of their effects, is; what the nature
of the febrifuge principle of chinchoa, and what its aétion on
our fyftem. Hehas fubjeéted to the aétion of the re-agents
pointed out for the febrifuge principle of cinchona, all chemical
and medicinal fubftances ; and affured himfelf, whether fuch of
thefe fubftances, as might contain the febrifuge principle, did —
not contain, at the fame time,' other fubftances prejudicial to
the animal economy. Laftly, he had to cure fevers by the
help of thefe remedies, and then confirm this theory by re;
peated experiments. Such is the courfe Cit. Seguin has
purfued. |
The febrifuge The new febrifuge principle, which he propofes to fubftitute
Sie. inftead of cinchona, becaufe it unites all the advantages of the
bark, without any of its inconveniences, is gelatine in its
pure ftate.
Advantages this Confidered in a medical, economical, and political view,
he over gelatine promifes much greater advantages than bark, in its
application to the cure of fevers. It occafions no irritation ;
procures quiet fleep and gentle perfpiration ; keeps the belly
open, without producing colic or naufea: has no unpleafant
flavour; reflores the ftrength, and is digefted even by the
weakeft ftomach, that would reject the "bat as foon as ad-
miniftered.
Difadvantagesof On the other hand, cinchona irritates the fyftem, difturbs
bark. the fleep, has a difagreeable tafte, frequently occafions cof-
tivenefs, and is very indigettiblas
Gomesorive In an economical view, there is ftill greater difference 8
cheapnefs o}
dictine, tween cinchona and gelatine; the price of the latter being to
that of the former at moft as one to thirty-two
Laftly, gelatine is indigenous, cinchona is oes ; and the
purchafe of the Jatter requires us to fend abroad a very confi-
derable fum of money, which might be kept at home by
adopting the ufe of gelatine.
Cafes cured by | To this memoir the author has fubjoined thirty-feven cafes,
‘es in which he performed a cure with gelatine, under the eyes of
fome refpeétable phyficians, and he has defired a Committee
to be appointed, to repeat his experiments, and report ie
them.
Committee ap- Accordingly Citizen Portal, Defeffarts, Hallé, Fourcroy,
pointed to exa-
imine its effects, Berthollet, and So bateces been nominated for this gone
‘ eir
SCIENTIFIC: NEWS. 139
Their experiments are made at the School of Medicine, in a
room. exclufively appropriated to thefe inquiries ; already awhich apgjar to
great number of patients have been cured ; and. the Com- (os nae, by
mittee will foon make their firft report on thefe cafes.
Query by a Correfpondent refpecting the Auguftine Earth,
To Mr. NICHOLSON.
SIR,
WE poffefs many excellent elementary works on Che- Auguftine earth,
_mifiry, both original and tranflations, fuch as Thompfon,
Aecum, Murray, Henry, Parkinfon, La.Grange, Green,
Fourcroy, Jacquin, &c. but in none of thefe authors is men-
tioned the method for obtaining the new earth, called Aux
gufine; although moft of thefe works have been publifhed a
confiderable time after this earth -was made known by the
German difcoverer, Profeffor Tromfdorf. .I have alfo made
enquiry, concerning this fubjeét, of moft of the public teachers
of chemiftry, and other individuals, who ftand high as che-
mical philofophers, but in vain ; I will therefore thank you to
allow thefe lines a place in your valuable Journal. Perhaps
one of your Correfpondents will be kind enough to favour me
_ with the procefs for obtaining this earth; for the author of
thefe lines cannot find it in the mineral which is faid to con-
tain it; having purfued the ufual methods of examining Mis
neral fubftances for that purpofe.
I am, R “*
SIR,
Your’s, &c.
P. O.
Spaniard faid to refit high Degrees of Heat and ftrong chemical
Agents,
THE prints of Paris, and fome of our own, too implicitly Extraordinary
co for fi bited a ft ftory of a Spa-
pying them, have for fome time exhibited a ftrange narra- Linciitin totied
tive ofa young Spaniard, born at Tolofa, and now 23 years fift heat and cor=
of age, of whom it has been very particularly affirmed, ‘Ave acids.
That
140
7
SCIENTIFIC NEWS.
That though his fkin exhibited no appearance of peculiarity,
either natural, or indicating preparation by art, yet without
injury, 1. He bathed his feet for fix minutes, and wafhed
his. hands. and face in oil heated to 250° of Fahrenheit, which
is 38 degrees hotter than boiling water. 2. He did the
fame with a folution of fea falt, heated 12 degrees higher.
3. He ftood with his naked feet upon a bar of iron near the
welding, or at the white heat ; he held the bar in this Rate in
his hands, and rubbed it on the furface of histongue. 5. He
wathed his mouth with the firongeft fulphurie and nitric acids,
and applied the fame to the other parts of his ikin, with no
other effeét than that the nitric acid produced a yellow.tinge ;
and 6. he remained a confiderable time in an oven heated to
within 18 degrees of the boiling water point.
Though our reafoning from analogy in matters of experi-
ment, is liable to miflead, as well by infufing too much doubt
as too much confidence, yet I fhould have paffed over this
tale without notice, if I hed not heard of it from very refpe@-
able correfpondents. I fuppofe there may be fomething ex<
traordinary in the degree of infenfibility of the fubjeét in quel.
tion, as the Inftitute has paid attention to him ; but I under-
ftand that the ftory is now told with great abatements. Citizen
Pinel, a man of information, and well known as an accurate
_ obferver, is commiflioned to report upon the fame; and } have
Flavour of malt
fpirits amended
Lute, eggs and
chalk, or flaked
dimes
uo doubt but his account will fhew how much eafier it is for
men to tell falfehoods than to reverfe the courfe of nature.
~
Method of giving Malt Spirits the Flavour of Brandy.*
INTO a quart of malt fpirits put three ounces and a half
of finely powdered charcoal, and four ounces anda half of
ground rice. Let. thefe ingredients remain during fifteen,
days, only obferving to ftir them often: at the expiration of
this time, let the liquor be ftrained, and it will be found to be
much improved.
Preparation of a Lute proper for Chemical Operations, By
C. Paysse, Profefor of Chemifiry.t |
IN the preparation of the oxigenated muriatic acid in the
large way, the neceffity I found for a lute, which, to the ad-.
* From the Bibliotheque Phyfique Economique, No. 10. An. XI.
+ From the Annales de Chimie, No, 137. An, XI,
vantage
SCIENTIFIC NEWS,
vantage of being cheap, fhould add thofe of being eafily pre«
pared ; of refifting the a@tion of the deftruétive. vapour of
the acid, as well as the ftrong heat which the luted part is
often required to bear; which fhould be eafy of application,
and im an uniform manner, and not harden too quick! y 3 obliged
me to make fome experiments on the fubje@, the refult of
which have been very fatisfa€tory.
After making a great number of mixtures. with different
fubftances, I made choice of the following, which produced
me a homogeneous compofition, drying as flowly as could be
defired, extremely hard; when dry, of a very compa@
texture; and, in fhort, poffefling all the properties I had
defired, ;
Take the white of two eggs, with their-yolks, and of pow-
dered carbonate of lime, or of quick lime well flaked in the
air, about half the weight of the eggs; fpread it on a cloth,
and apply it as a lute.
NOTE.
THIS lute, the compofition of which is very fmple, pof-
feffes a degree of elafticity, when dry; I have formed veflels
of it, which are impermeable to water, and fufceptible of
being polifhed on the wheel. This compofition refembles the
fubRance of which the pipes, called Meerfhaum, are made.
Two new Quadrupeds.*
Two living Quadrupeds have lately been received at the
: Mufeum of Natural Hiftory at Paris, which are entirely un-
_ known among naturalifts, and were brought to Europe by
Captain Baudin. Profeffor Geoffroy (of Egypt) who has in-
ferted a defcription of them in the annals of the Mufeum,
calls them Fafcolomes. They come from the wettern coaft of
New Holland; their fur promifes to be of fome ufe; and,
“according to the opinion of Captain Hamelin and his fuite,
their flefh is very excellent food. They are particularly inte-
refting to naturalifts from the fingularity of their organization.
In the form of the head, the number, arrangement, and na-
ture of the teeth, and the form of the fore feet with which
* Decade Philof. No. 51, An, XT,
tthey
141
Two new Qua-
drupeds from
New Holland,
142
:
fenee of iron
m ruft.
SCIENTIFIC NEWS.
they butrow in the earth, they refemble the marmot ; but
they differ from them, by the female having a pouch beneath
the belly, and by the whole ftruéture of the organs of gene-
ration, in which they are fimilar to the farique of Buffon.
The form of the hinder foot is the fame as in that animal
with a pouch; the thumb being diftin@ from the other fingers;
and without a nail: the tail is fo fhort, that it remains hid be-
below the hair, which is brown, bufhy, and very long. The
Fafcolomes of the Menagerie are yet young, but are already
larger than rabbits. Their temper is admirable ;: they may be
handled, or removed, without fhewing any fymptoms of fear;
anger, or uneafinefs ; their movements are heavy and clumfy ;
they live under ground, fleep during the day, and go in fearch
of food at mght. In ‘general they poflefs but little energy or
aftivity ; they fcratch themfelves like the monkey, and they
may be fed with bread, milk, roots, and every fort of
herbage.
Prefervation of Iron from Ruft.
CIT. Conté has adopted a method, which he finds
effe@tual, for preventing the oxidation of iron and fteel ;
or, -in popular terms, to prevent iron and fteel from rufting.
It contifts in mixing with fat oil varnifh, at leaft half, or at
moft four-fifths of its quantity of highly reétified {pirits of tur
pentine. This varnifh muft be lightly and evenly applied
with a fponge ; after which the article is left to dry in fome
fituation not expofed to duft. He affirms, that articles thus
varnifhed retain their metallic luftre, and do not contra€ any
{pots of ruft. This varnifh may alfo be applied to copper, of
which it preferves the polifh, and heightens the colour. I¢
may be employed with particular advantage to preferve philo-
fophical inftruments from any change, in experiments where,
by being placed in conta& with water, they are fubje& to
lofe that polifh and precifion of form which conftituted part of
their value.
ACCOUNT
AGGOUNT OF NEW BOOKS:;*
| ACCOUNT OF NEW BOOKS.
Philofophical Tranfa@ions of the Royal Society of London, for
the Year 1803. Part I.
Tue Contents of this Part are, 1. The Bakerian Le@ure,
Obfervations on the Quantity of horizontal Refra€tion; with
a Method of meafuring the Dip at Sea. By William Hyde
Wollafton, M.D. F.R.S. 2. A Chemical Analyfis of fome
Calamines. By James Smithfon, Efq. F.R.S. 3. Experi-
ments on the Quantity of Gafes abforbed by Water at different
Temperatures and under different Preffures. By Mr. William
Henry. 4. Experiments and Obfervations on the various
Alloys, on the Specific Gravity, and on the comparative Wear
of Gold, » Being the Subftance of a Report made to the Right
Honourable the Lords of the Committee of the Privy Council,
appointed to take into Confideration the State of the Coin of
this Kingdom, and the prefent Eftablifhment and Conftitution
of His Majefty’s Mint. By Charles Hatchett, Efg. F.R.S.
5. Obfervations on the Chemical Nature of the Humour of
the Eye. By Richard Chenevix, Efq. F.R.S. and M.R.I.A.
6. An Account of fome Stones faid to have fallen on the Earth
in France, and a Lump of Native Iron faid to have fallen in In-
dia. By the Right Honourable Charles Greville, F. R.S.
7. Obfervations on the Struéture of the Tongue, illuftrated by
Cafes in which a portion of that Organ has been removed by
Ligature. By Everard Home, Efq. F.R.S. 8. Obferva-
tions on the Tranfit of Mercury over the Difk of the Sun; to
which is added an Inveftigation of the Caufes which often
prevent the proper A@tion of Mirrors. By William Herfchell,
LL. D.F. R.S.&c. 9. An Account of fome Experiments and
Obfervations on the Conftituent Parts of certain Aftringent
Vegetables; and on their Operation in Tanning. By Hum-
phry Davy, Efq. Profeffor of Chemiftry in the Royal Infti-
_ tution. 10. Appendix to Mr. William Henry’s Paper, on the
— Quantity of Gafes abforbed by Water, at different Tempera-
tures, and under different Preffures.*
we APPENDIX.
Meteorological Journal kept at the Apartments of the Royal
Society, by Order of the Prefident and Council.
* Our Readers will obferve, that we have as ufual, reprinted in
- our Journal moft of thefe valuable Papers,
An
143
144 ACCOUNT OF NEW BOOKS.
An Effay on the Law of Patents for new Inventions ; 40 which are
prefixed Two Chapters on the general Hiftory of Monopoliess
and on their Introduétion and Progrefs in England, to the Timé
of the Inter-regnum: with an Appendix containing Copies of
the Caveat, Petiteon, Oath, and other Formula, with an ar-~
ranged Catalogue of all the Patents-granted from tlie \ft of Ja-
nuary 1800, to the prefent Time. By Joun Dyer Couture,
1803. . Longman and Rees, Royal 8vo.
One of the moft obvious expedients for taxing the induftry
of man in focial life, but at the fame time one of the moft pers
nicious, confifts in monopolies, Accordingly we find in all
governments that this refource is more or lefs adopted, and _
trades, manufactures, and various operations, become confined,
to the excutive power, or what is worfe, to the private fas
vourites of men of influence. A long feries of years have
elapfed fince this nuifance was abolifhed in our country, by the
ftatute of James, and the monopolies that yet remain, are
under the dire@ fanétion of law, and fo few, that a common
obferver would be difpofed to fay we have none.
A clafs of monopolies which has conftituted the fubjeét of
a claufe of exception in that aét, confifts in the fole working
and making of new manufaétures for a limited time under royal.
grant, to the firft and true inventor thereof. It has beena
fubjeét of difcuffion whether even this exclufive privilege which
is often made the inftrument of public deception, and fome-
times of oppreffion by wealthy Individuals to crufh the induftry
of ingenious men by expenfive legal proceffes under letters
patent, for objeéts of public poffeffion; it has often been dif-.
puted whethker this exclufive privilege be a benefit or an evil.
The faéts I think are, that many private fortunes are loft, in
{upporting pretended inventors, or in bringing real ones into
effect, and that our arts, trade and fciences are greatly bene-
fitted by this laft operation ;—
The fubjeét of patents and monopolies in general is there-
fore of great intereft and praQical importance, and I have no
doubt the public will receive this compendium as a valuable
addition to their means of information refpe@ting them.
A
JOURNAL
NATURAL PHILOSOPHY, CHEMISTRY,
AND
DE SA Ros:
NOVEMBER, 1803.
ARTICLE. L
Experiments and Obyjercations on the various Alloys, on the Specific
Gravity, and on the comparative Wear of Gold. Abftraéted
Jrom the Memoir of Cuarues Hatcuert, Ey. F.R.S.
nthe Philof. Tranf: for 1803.
(Concluded from Vol. V. Page 303 of our Journal.)
Esaperimen i.
ae pieces of ftandard gold were firft ae a and Lofs of ftandard
were placed fo that fix were ale to fix. gold by friétion,
The brafs frame, in which each upper piece was, fixed,
~ weighed 1604 grains; and it was found neceflary to. add to
each a weight of lead, equal to 19825 grains; fo that the
pieces were rubbed againft each other under the preffure of
19825-+1604=21429 grains = 3 lb. 80z. 12dts. 21 grs *
* This weight was not employed till repeated trials had proved
the extreme difficulty, and almoft impoffibility, of producing any
perceptible effeét with lefs, in a moderate period of time; and,
even with this weight, the experiments were found te be exceed-
ingly tedious. The only evil which refulted from fuch a preffure
' was, that the comparative wear of the fine gold appeared much
more confiderable than would have been the cafe, if a {mall weight
could have been employed; fome obfervations will therefore be
found in the fubfequent pages, which point out the neceflity of
making an allowance for this circumftance.
» Vor. VI.—NovemBer, 1803, L The
146 EXPERIMENTS ON VARIOUS ALLOYS OF GOLD,
The machine was then put in motion, until the index fhowed
that 286690 revolutions had been performed ; and, as a double ©
crank aéted during each revolution, the pieces were rubbed
againft each other alternately, in oppofite direétions, 573380
times, being twice the number of the revolutions.
The twelve pieces of ftandard gold, being taken out, were
: weighed, and were found to have loft 8,60 grs.
Experiment ee
Of gold alloyed | Twelve pieces of gold combined with an equal proportion
with an unequalof copper, and without any impreffion, loft 103,11 grs. in
weight of copper. Epes ge Se 4 4 riabteieh
70640 revolutions.
Experiment Ill.
Of fine copper, Mrwelve fimilar pieces of fine copper, loft 174,80 grs in
22200 revolutions.
Hence it appears, that ftandard gold lofes lefs by friétion
than gold much debafed by copper, and this lefs than copper
alone.
Gold alloyed The next feries of experiments was made with gold dif-
Aa la ae ferently alloyed; when gold 1. made ftandard by copper, 2.
aS ae reduced to 18 carats by copper, 3. made ftandard by copper
and filver, 4. made ftandard by filver, 5. of 23 car. 3% grs. fine,
6. made ftandard by tin and copper, 7. made ftandard by iron
a copper, 8. alloyed with an equal quantity of copper, was
found to have loft in the following proportions, in the order
in which they have been enumerated. Ogrs. Ogrs. 0,10 grs.
0,10grs. 4,20 grs. 15,30grs. 21,60 grs. 65,78 grs. The wear of
the pieces alioeed with equal parts of gold and copper, and
with iron and copper, was fo rapid, that they were obliged
to be taken out of the machine after 105480 revolutions ; and
thofe containing tin were worn fo thin in 189000 revolutions,
as to require being removed: the reft fuftained 200300 re-
volutions, whence their comparative lofs was ftill lefs than
as above given.
Gold fimilarly This experiment being rite on fmooth, flat pieces, it was
Monae repeated with others of fimilar compofition ftamped with the
die before defcribed, only omitting the compound of equal
parts of gold and copper, and adding pieces of ftandard
filver and of fine copper. The number of revolutions were
only 20680, and the pieces, taking them in the order already
mentioned, now loft refpeétively : 0,60 grs. 4,80 grs. 1,20 grs.
3,58
wT
EXPERIMENTS ON VARIOUS ALLOYS OF GOLD.
3,50 grs. 4,60 grs. 13,80 grs. 7,60 grs. The ftandard filver
loft 3,70 grs. the fine copper 46,30.
147
Standard filver .
and fine co »pper -
From comparing the effeéts produced with the number of re- raifed furfaces
volutions, it is obvious, that much more is loft in the friétion
of emboffed furfaces, than of plain.
The experiments were afterwards varied by placing pieces
of the different compofitions in fuch a manner, that in fome
cafes the friétion fhould be between fimilar pieces, in others,
between thofe differently alloyed. The refults of all thofe
experiments are tabulated, but they would occupy too much
room to enter into them minutely; and though, from un-
avoidable circumftances, fome little inaccuracies oeca-
fionally occurred, they may be concluded, as Mr. H. obferves
to prove:
ift. That fine sale, or of 23 car. 32 grs. when expofed to
friétion againft gold of an equal quality, under the preffure of
a confiderable weight, fuffers a very notable lofs; and, al-
though various circumftances feemed to indicate, that but
little effeét, in refpeét to abrafion, is produced under a lefs
weight, yet it muft be remembered, that the firft cafe may
occur. * .
Moreover, that fine gold, under all circumftances, is more
fubje€t to have any raifed parts of its {urface obliterated, than
any variety of alloyed gold; not always, nor indeed fo much,
* It is proper to remark, that the preceding experiments were
made under a much greater weight than can be fuppofed to operate
generally during the circulation of money ; and as, by fome pre-
vious experiments, a lefs weight was found to produce, during a
certain time, little or no effect, it may be fufpeéted, that although,
under a greater preffure, fine or very ductile gold fuftains a greater
Jofs than fome of thofe which are reduced to ftandard, yet, under
a lefs preffure, or fuch as that which moft commonly prevails in the
courfe of the ufual wear of coin, the reverfe may probably be the
cafe ; for then the fame caufes operate with le{s rapidity, during a
long period of time. From many various circumftances, there is
reafon therefore to believe, that the wear of coin againft coin of a
fimilar quality is, under a fmall or very moderate weight, in the
inverfe ratio to the degree of duétility; but this is only to be un-
derftood in the abovementioned cafe, of coin rubbed againft coin of
equal quality.
Leg by
lofe moft.
Fri€tion be-
tween fimilar
and diflimilar
pieces.
Fine gold.
Wear of coin
in the inverfe
ratio of its duce
tility.
148
Standard gold.
Gold with iron
or tine
¥8 carat gold,
with copper.
Gold much de-
bafed with cop-
per.
Difadvantage of
foftnefs in coin.
EXPERIMENTS ON VARIOUS ALLOYS OF GOLD,
by a@tual abrafion, as. by having the protuberant parts preffed
and rubbed into the mafs, in confequence of its extreme foft-
nefs and duétility.*
2d. That fine gold, or of 23 car. 32 grs. when rubbed
againft the various kinds of alloved gold, always or pong
fuffers the greateft comparative lofs.
3d. That gold reduced to 22 carats, or to fanttond by
filver, or by filver and copper, or merely by copper, fuffers
by friction, under general and fimilar cireumftances, a {maller
diminution than the fine gold abovementioned; and, with or
without abrafion, the protuberant parts on the furfaces of
thefe pieces remain much more permanent, under all circums
flances, than thofe of the fine gold. The difference of wear
between the three kinds of ftandard gold abovementioned,
does not in reality appear to be very confiderable ; but, upon
the whole, the preference may be given to gold alloyed with
a mixture of filver and copper, or to that which has only
copper for the alloy.
4th. That gold made ftandard partly by the addition of
iron or tin, fuftains a greater lofs by fri€tion than either of the
three kinds of Gamaeed gold above-mentioned.
5th. That gold reduced to 18 carats by copper, is more
liable occafionally to wear, in a {mall degree, than the three
kinds of ftandard gold which have been lately mentioned,
provided that the friétion takes place between pieces of equal
quality ; but, in the contrary cafe, the principal lofs always
falls on the foft or ftandard gold, when it is oppofed to gold
of 18 carats, which is confiderably harder.
6th. That gold more debafed than that of 18 carats, fuch as
gold alloyed with an equal proportion of copper, fuffers very
confiderably msore than any of the kinds hitherto mentioned,
provided that the pieces are of the fame quality ; but, on the
contrary, fine and ftandard gold experience a very great lofs,
when expofed to the aétion of this debafed gold, while the
lofs of the latter is comparatively much lefs.
* This is, however, of much confequence; for, although coin
may not fuffer by actual abrafion, yet, if the impreffion made upon
it can fo foon be deftroyed, it follows of courfe, that the pieces be~
come (although ftill allowed to be current) no better than mere
blanks, or fragments of a bar or ingot.
7th
EXPERIMENTS ON VARIOUS ALLOYS OE GOLD, 149
7th. That the wear of ftandard filver appears to be nearly Standard filver.
equal with that of fine gold; but more than that of gold
_ made ftandard by filver or by copper, and lefs than that of
gold much debafed by copper.
8th. That, as gold which is not inferior to ftandard wears
, in general lefs than ftandard filver, fo does this laft fuffer much
lefs than copper,
The lofs fuftained by copper, when rubbed againft copper, Copper:
is infinitely more than that of the former metals; and, when
thefe are expofed to the a@tion of copper, they, as well as the
Copper, fuffer a very confiderable lofs. This appears from
the general refults of thefe experiments, which prove, that
pieces of metal which are the moft fubjeét to wear,, are
thofe which produce the greateft lofs upon other pieces of
metal, when rubbed againft them; and it is remarkable, that
in fuch a cafe, the lofs does not always fall on one in preference
to the other ; fo that the wear can only be confidered in the
aggregate, although one of the pieces may be regarded as the
principal caufe,
In order, however, to illuftrate the refults of the preceding
experiments, as far as they concern the fofter and harder
kinds of ftandard gold, and to afcertain more fully the com-
parative wear of flat and fmooth furfaces with that of {uch as
were partl; protuberant, an experiment was made, with two
kinds of ftandard gold: 1f. Gold made ftandard by fine Gold made
Swedifh copper, which was very du@tile; and, 2d. Gold shah dl che
made ftandard by a mixture of fine Swedifh copper and dollar copper.
_ copper. This was as brittle as was compatible with rolling
_ and ftamping; and was prepared by melting gold made
_ ftandard by fine Swedifh copper, with an equal quantity of
_ gold rendered brittle by the ftandard proportion of Swedith
' dollar copper, which was mentioned in the firft feGion of
_ this paper. >
S «© It may here be obferved, that a diftinion muft be made Diftin@tion be-
_ between hard and brittle metal. If a metal is difpofed to en ate
crack when rolled, without requiring any extraordinary force
_ to enable it to pafs the rollers, then it may be regarded as
brittle; but, if it requires an extraordinary force to make it
: pals the rollers, and is not difpofed to crack, then it may be
_ confidered as hard,
, This
150 EXPERIMENTS ON VARIOUS ALLOYS OF GOLD.
This experiment proves,
Very duttile 1ft. That very duétile ftandard gold, when expofed to the’
eae 80l4 frition of gold of a fimilar quality, fuffers lefs by abrafion than
gold which is comparatively brittle, or harder, and which is
fubje€ted to friétion under the fame circumftances.
2d. That when foft gold and brittle or hard gold rub
again{t each other, the greateft lofs is fuftained by the foft
gold. And,
3d. That pieces which have raifed or emboffed furfaces,
fuffer a greater lofs, under every circumftance, than thofe
which are fmooth and flat. ;
Coin rubbing | The whole of the foregoing experiments were made with
nae ee the machine called No. 1; and, as the fri€tion was conti-
lation, lofes but nued, in each experiment, during many days, with a prefiure
Berle. upon each couple of pieces equal to 3 lbs. 80z, 12 dts. and
21 grs., and as (confidering the feverity of fuch a trial) the
lofs fuftained by the pieces, feparately or colleétively, was
not very confiderable, it may with reafon be inferred, that
ftandard gold does not eafily fuffer abrafion by the friétion of
metal againft metal, or of coin againft coin, efpecially under .
the circumftances which commonly prevail during the circula-
tion of money.
In the machine No. 1, the pieces of gold were oppofed
face to face ; it now therefore appeared proper, that the faéts
thus afcertained concerning the wear of gold, of different
degrees of duétility, fhould be farther examined, and corro-
borated by a different methed. To effe& this, the fecond of
the machines before defcribed, was employed. 4
Emperimicn Two hundred pieces of gold, of five different qualities,
with machine, x ‘ : i
RG e: were employed in this experiment; twenty pieces of each
‘kind were plain and fmooth, the others were ftamped with
the die already mentioned. The two hundred pieces were
mingled, and were enclofed within the cubic box.
Different quali- The following were the qualities of the gold. 1. Gold of ~
ai plelities thy a 32 grs. 2. Gold made ftandard by filver. 3. Gold
made ftandard by filver and copper. 4. Gold made ftandard
by fine Swedifh copper. 5. Gold made ftandard by equal
parts of fine Swedith copper and dollar copper.
Their lofse After 71720 revolutions of this machine, performed in 40
hours, the lofs fuftained was found to be as follows: of No. 1.
the
EXPERIMENTS ON VARIOUS ALLOYS OF GOLD. 151
the unftamped pieces 92,8 grs.. ftamped, 95,6 grs. No. 2
-unftamped, 63,5 grs. ftamped, 60,1 grs. No. 3, unftamped,
12 grs. flamped, 11,7 grs. No.4, unftamped, 18 grs. ftamped,
19,2 grs. No. 5, unftamped, 13 grs. ftamped 12,1 grs. The
total weight of the unfiamped pieces, before friGion, was :
13701,3 grs. Their total. lofs, 199,3: the weight of the
fiamped, 13679,5; the lofs.198,7
All the pieces appeared to ba fuffered more on the edges Edges worn
than on the faces ; and thofe which were ftamped had the im- mot;
preffion more or lefs obliterated or flattened, in proportion to
their refpeG&ive degree of duétility, or to the lofs which
according to the refult of this experiment, they had rela-
tively fuftained.
The different pieces, after the experiment, had a curious 2 raifed bead
appearance ; for, on the edges, which were become round wile ache
and polifhed, a fmall regular raifed bead or moulding was
formed, which furrounded each face, like a frame; and both the faces con-
faces were become more or lefs concave. ad
The original diameter of the pieces was alfo diminiflied, The diameter
nearly according to their different degrees of duétility, and ac- diminithed.
cording to the lofs which they had experienced in confequence
of the operation.
The meafure of the diameters of the pieces, after the ex-
periment, was,
Gold 23 car. 3 grs. eight-tenths of an inch and 3
_ Gold alloyed with filver, nine-tenths of an inch.
The others varied litle from nine-tenths and =; which
was lefs, by about 4, of an inch, than the originai diameter
of the pieces; and a was evident, that. the pieces of fine
gold, and thofe confifting of gold alloyed with filver, being
the moft du@tile, had fuffered the greateft lofs, and were moft
diminifhed in diameter. Upon the whole, therefore, this ex-
periment appears to corroborate what has been afferted con-
cerning the former, viz. that foft or duétile gold fuffers the
greateft lofs, when expofed to friction in contaét with gold
which is comparatively harder. Thefe experiments for afcer-
taining the effects arifing from the fri@tion of coin againft coin
being gone through, another feries was commenced with the
apparatus, No. 3, by means of which various pieces were ex- Apparatus,
pofed to the aétion of certain powders and filings’of metals, No- 3¢
which were feparately fprinkled upon the horizontal table.
7 The
152
Friction of gold
by whiting,
fand, filings of
ftandard gold,
and of iron.
General refults.
Fine gold lofes
its impreffion.
Very hard gold.
improper for
coin; Why.
EXPERIMENTS ON VARIOUS ALLOYS OF GOLD,
The pieces were properly fixed in their refpe€tive fockets ©
and frames, and were placed fo as to bear upon the table,
with or without additional weights. :
The table was moved by a wheel and pinion, fo calculated
as to avoid too rapid a motion; and the revolutions were de-
noted, as in the former experiments, by means of a counter.
The table was covered with fine powdered whiting, with
fine white writing fand, with filings of gold made ftandard by
copper, and laftly filings of iron. The laft three were fixed
on the table by means’of a folution of ifinglafs. Geld of dif-
ferent kinds as before, ftandard filver, and fine copper, both
ftamped and unftamped, were fubjeéted to the different
trials.
From the whole of the preceding experiments, made with
the three different machines, viewed and compared together,
the author infers.
1ft. That when equal friction, affifted by a moderate pref- —
fure, takes place between pieces of coin of a fimilar quality,
abrafion is moft commonly produced in an inverfe ratio to the
ductility. *
2d. That the contrary effeét happens, when pieces of dif-
ferent qualities rub againft each other ; for then, the more duc-
tile metal is worn by that which is harder.*
3d. That earthy powders and metallic filings produce
fimilar effeéts, and tend to wear the different kinds of gold
in proportion to their refpe€tive degrees of duétility.
Fine gold, being extremely foft and duétile, fuftains a con-
fiderable lofs, under many of the general circumftances of
fri€tion ; and as at all times it appears certain, that the im-
preflions which have been ftamped upon it are moft eafily
obliterated, even when aétual abrafion does not take place,
there is much reafon to conclude, that gold of fuch extreme
du@tility is not that which is the moft proper to be formed
into coin.
But gold of the oppofite quality, or at leaft fo hard as to
be juft capable of being rolled and ftamped, feems to be
equally improper for the purpofe of coin. For, even fup-
* Some experiments made at Paris, in 1790, upon pure and upon
alloyed filver are concifely mentioned, the refults of which appear
to be nearly the fame as thofe of the prefent experiments upon gold.
pofing
—
_ EXPERIMENTS ON VARIOUS ALLOYS OF GOLD.
- pofing that hard gold fuffered, in every cafe, lefs by fri€tion
than that which is moderately dutile, (which is not however
the fact,) and allowing that ftandard gold may, by a mixed
alloy, be rendered as hard as gold reduced by copper to
18 carats, without changing the ftandard proportion of gold,
yet it would be very difficult always to make fuch ftandard
gold of an uniform degree of hardnefs. Moreover, by fome
experiments which Mr. H. purpofely made at the Mint, upon the
rolling and ftamping of gold of different qualities, it evidently
appeared, that gold equal in hardnefs to that of 18 carats,
could not be employed with advantage; for, the additional
labour which was required for the rolling and ftamping of
this hard gold, the frequent failure in making the impreffion,
and the battering and breaking of the dies, fully proved, that
the expence and difficulty attending the working of fuch
gold, would by no means be compenfated by any fmall degree
of durability which it might poffefs over any other.
The extremes of duétility and of hardnefs being therefore
equally obje@tionable, it follows of courfe, that gold of mo-
derate duétility muft be that which is the beft adapted for
_ coin; and, as nothing but filver or copper can be employed
to alloy gold which 1s intended to be coined, it may be here
obferved, that whatever might have been the original motive
for introducing the prefent ftandard of 22 carats, yet it ap-
pears, from the experiments lately defcribed, that this pro-
portion of +. of the above-mentioned metals, is (every cir-
cumftance being confidered) the beft, or at leaft as good as
any, which could have been chofen.
There is, however, fome difference in the quality of gold,
when alloyed with the ftandard proportion of filver, of filver
and copper, and of copper, which requires to be con-
fidered.
- Gold alloyed with one-twelfth of filver, is of a fine but
pale yellow ; it is very duétile ; it is eafily rolled, and may
be ftamped without being annealed ; it confequently does
not require to be blanched ; and, after the complete procefs
of coining, the furface and every part remains of an uni-
form quality, fo that, by wear, it does not appear of different
_ colours.
- Thefe properties are certainly much to be valued ; but the
objections to this kind of ftandard gold are,
ift.
153
Gold of mode-
rate ductility
beft.
Gold alloyed
with filver 5 its
advantages 5
*
154
Its difadvan-
tages 5
with equal parts
of Gilver and
copper 3 its ad-
vantages 5
its difadvan-
‘tages:
EXPERIMENTS ON VARIOUS ALLOYS OF GOLD.
Ift. The additional expence attending the ufe of filver as
an alloy. .
2d. Theextreme pale yellow colour. And,
3d. That, from its great du@tility, it is almoft as liable to
have the impreflions which have been made upon it obliterated,
as thofe which have been made upon fine gold.
All things being therefore confidered, gold alloyed only
with filver, does not appear to be fo proper for coin as may
at firft be imagined.
Gold made ftandard by a mixture of equal parts of filver
and copper, is not fo foft as gold alloyed only ‘with filver ;
neither is it fo pale, for it appears to be lefs removed from the
colour of fine gold than either the former or the following
metal. i
Gold alloyed with filver and copper, when annealed, does
not become black, but brown; and this colour is more eafily
removed by the blanching liquor, or folution of alum, than
when the whole of the alloy confifts of copper. It may alfo
be rolled and fiamped with great facility ; and, under many
circumftances, it appears to fuffer lefs by fri€tion, than gold
alloyed by filver, or by copper alone,
But, afler it has been -fubjeéted to the ordinary friétion
which muft take place during the circulation of money, it is
liable to appear of a deeper colour in thofe parts. which are
alloyed with
copper alone.
prominent, and are confequently the moft expofed to friétion.
This defe& arifes from a caufe which will foon be explained,
but it cannot be regarded as an objeétion of any weight.
The laft kind of ftandard gold which remains to be men- -
tioned, is that which is alloyed only by copper. This is of a
much deeper colour than thofe which have been hitherto no-
ticed, and it is flightly harder than either of them ; but ne-
verthelefs it is very duétile, provided that the copper be pure.
It requires to be annealed, and then becomés nearly or quite
black: which colour is not fo eafily removed by the blanch-
ing liquor, as that.which is produced by the procefs of
annealing, upon gold alloyed with a mixture of filver and
copper. |
It fuffers lefs by many of the varieties of fri€tion, than gold
‘which is alloyed with filver ; but, in fome'cafes, it feems to
wear rather more than gold alloyed with filver and copper ;
the difference is not however very confiderable.
This
EXPERIMENTS ON VARIOUS* ALLOYS @F GOLD. 155
This fort of ftandard gold, as well as that which is alloyed
with filver and copper, appears commonly, after a certain de-
'. gree of wear, of a coppery colour, more or lefs deep, in thofe
parts which are the moft prominent; and, when coin thus
alloyed exhibits fuch an appearance, it is frequently and vul-
garly faid to have been in. contact with copper money ; and.
fometimes guineas having this appearance have been refufed,
upon the fuppofition that they were debafed. But the real
fact is, that when copper conftitutes part or the whole of the
alloy, it becomes oxidized or calcined upon;the furface of the
blanks, by the procefs of annealing ; and the blackith cruft of
-copper, in this ftate, muft then be removed by the folution
of alum, called the blanching liquor. Now it is evident,
that after this operation, the furfaces of the blanks or un-
unftamped pieces, can no longer be regarded as ftandard gold.
For, if copper alone forms the alloy, it muft be diffolved and
-feparated from the furface of each piece of coin; and the
fame effect muft alfo take place, with refpeét to the copper,
in the alloy formed of copper and filver.. So that, in the
firft cafe, each piece, when blanched, will confift of gold
made ftandard by copper, covered with a thin coat of fine
gold; and, in the fecond cafe, each piece will be compofed
of gold made ftandard by filver and copper, coated with gold
alloyed with 4. of filver, or with half of the ftandard pro-
portion of alloy, fuppofing the filver and copper to have been
in equal quantities. As, therefore, the ftandard gold of
which the pieces confift is always, more or lefs, of a
deeper colour than the coating or film of the finer gold
which covers each piece, it muft be evident, that when this
coating has been rubbed and removed from the raifed or pro-
minent parts, thefe will appear of a very different and deeper.
colour than the flat part or ground of the coin. The reafon
thereforé is fufficiently apparent, why gold which is alloyed
with filver only, cannot be liable to this blemifh.
Upon a comparifon of the different qualities of the three Comparifon of —
kinds of ftandard gold which have been lately mentioned, it ee
appears, (ftri€tly fpeaking,) that gold made ftandard by
filver and copper is rather to be preferred for coin; but,
as gold’ made ftandard by copper alone is not very much ins
ferior in its general properties, it may be queftioned, whe-
ther. the few advantages which are thus gained, will com-
penfate
156
Extraordinary
lofs fuftained by
our gold coin not
imputable to fair
Wear.
EXPERIMENTS ON VARIOUS ALLOYS OF GOLD.
penfate the additional expence of the filver required for half of
the alloy; and, indeed, any extraordinary addition of filver
appears to be the lefs neceflary, as there is commonly fome
filver in the gold which is fent to the: Mint, which, being
reckoned as part of the alloy, contributes to produce thofe be-
neficial effeéts which refult when filver is purpofely added.
Froma general view of the prefent experiments, there does
not appear to be any very great or remarkable difference in
the comparative wear of the three kinds of ftandard gold, all
of which fuffer abrafion flowly, and with much difficulty ; and
(as it has been already obferved) the difference of wear between
the two laft mentioned, is certainly but inconfiderable. For
thefe reafons, and from the confideration of every other circum-
ftance, it muft be evident, that the extraordinary lofs which
the gold coin of this kingdom is ftated to have fuftained within
a certain limited time, cannot, with even a fhadow of proba-
bility, be attributed to any important defeét in the compofition
or quality of the ftandard gold ; and all that can be faid upon
this fubjeét is, that fome portion of this lofs may have‘been
caufed by the rough impreffion and milled edge now in ufe,
by which each piece of coin aéts, and is acted upon by the
others, inthe manner of a file.
The lofs thus occafioned cannot however be confiderable ; for
the quality of the prefent ftandard gold is certainly that which
is well adapted to refift abrafion, efpecially in the cafe of the
frition of coin againft coin ; and this is ftrongly corroborated
by the obfervations of bankers and others, who are in the babit
of fending or receiving large-quantities of gold coin from any
confiderable diftance. When a number of guineas, rather
loofely packed, have been long fhaken together by the motion
of acoach or other carriage, the effects of friétion are obferved
chiefly to fall upon only a few of the pieces, But it is not a little
remarkable, that although thefe are often reduced nearly or
quite to the ftate of plain pieces of metal or blanks, yet, upon
being weighed, they are found to have fuftained little or no
Jofs; and from this it appears, that the imprefliions have been
obliterated, not by an aétual abrafion of the metal, but by the
depreffion of the prominent parts, which have been forced into
the mafs, and become reduced to a level with the ground of the
coin. Pieces of hard gold would not fo eafily fuffer by depref-
4 fion;
EXPERIMENTS ON VARIOUS ALLOYS OF GOLD. 157
fion; but the real lofs would probably be greater, they being,
in the cafe of the friétion of coin againft coin of fimilar quality,
more fufceptible of abrafion.
Upon the whole, there is every reafon to believe, that our
gold coin fuffers but little by friction againft itfelf ; and the
chief caufe of natural and fair wear probably arifes from extra-
neous and gritty particles, to the a@tion of which the pieces may
occafionally be expofed in the courfe of circulation. But ftill it
muft be repeated, that the united effeéts of every fpecies of
friétion to which they may be fubjeéted, fairly and unavoidably,
during circulation, cannot produce any other. wear than that
which is extremely gradual and flow, and fuch as will by no
means account for the great and rapid diminution which has
been obferved in the gold coin of this country. :
SLC PION LL.
ON THE SPECIFIC GRAVITY OF GOLD WHEN ALLOYED
BY VARIOUS METALS.
Difficulties in afcertaining the fpecific gravities of bodies, The problem of
particularly from the inaccuracies of balances, the application aR i hig
and temperature of water, and the porofity of the objeét itfelf, tended with nu-
~ Metals vary in their denfity by cafting in a mould, by fpeedy Bac diffi
or flow cooling, and by hammering. ae
Hammering and rolling is an imperfeét remedy, and not ap- Hammering.
plicable to the brittle metals.
The effeéts of alloys on the fpecific gravity of gold are very Alloys affeé&
shine : > . the fpecific gra-
intricate, and only capable of being determined by a direét zlteae cals caer
trial; for a numerous feries of experiments clearly proved, not fingularly.
only that the {pecific gravity of the compound may differ from
the mean of the component parts, but that the effeét of the
~ fame alloy, inftead of being proportionate to the quantity em-
= of pure filver, as it produced only an expanfion of 0,10.
ployed, may differ confiderably from this. To the peculiar Compound
effets produced by certain proportions of fome of the metals @lloys-
mutt be added the effeéts peculiar to certain compound alloys,
_ whence arifes an immenfe complicated feries of alterations in
fpecific gravity, never yet inveftigated by philofophers.
With regard to the expanfion or contra€tion of the compound, Expanfion pre-
little alteration appears to be produced by alloying gold with a an gat by
3
" With copper it was 0,66: with equal parts of filver and cop- copper ;
per
4
158 EXPERIMENTS ON VARIOUS ALLOYS OF GOLD.
<i, per the expanfion was 0,67 ; with iron it was0,44; withiron
Contraétion by 22d copper 0,37. Tin, bifmuth, zinc, and antimony, pro-
tin, bifmuth, duced a contraétion. Lead and bifmuth very much refemble
et bac an each other in their effeéts on gold, and in the irregularity of
thefe in various proportions.
Miftake of Mr. Briffon has obferved, that on alloying gold with ,% of
Briffon in the copper, a mutual penetration takes place ; but in the ébuTe of
oe ae the prefent experiments the reverfe of this was found. It is
probable, therefore, that his experiment was made with part
of a large bar or ingot; as the unequal diffufion of the alloy,
the quantity of the metal, and the nature, form and pofition
of the mould, are all capable of affeéting the fpecific gravity.
Specific gravity Thus, when the mixture is perfect, the bottom of a bar caft
is raarae in a vertical mould will be of the greateft {pecific gravity,
ous circum- owing to the preffure of the fuperincumbent metal, while the
Bae, quality of both ends appears equal by the affay. On the con-
Differences in : ; . A i %
the fame bar. trary, if the mixture be imperfect, the lighter metal flowing
Whence. out of the crucible firft, will render the bottom of the bar in-
ferior both in quality and in fpecific gravity, as was found by
experiment.
Unequal diffu- “This unequal diffufion of the alloy through the mafs, the
fion of alloy. exact diftribution of which is not fo eafy as may be imagined,
particularly in large quantities, is the moft frequent caufe of
the variation in the f{pecific gravity of ftandard gold. The dif-
ficulty has been confidered, and an allowance made for it,
called the remedy for the mafter of the mint. Even when
Mixed metals metals have been completely mixed, if they be kept in fufion
feparate under under certain circumftances, a feparation, more or lefs perfeét;
fphon: fometimes takes place. This feparation appears to be accord-
ing to the relative affinities and {pecific gravities of the two
metals, and is the fooneft effected when the metals have not
been perfeétly mixed *.
Long continued — Befide the caufes mentioned there is another, that occafions
fiiétion lefens yarjations more or lefs confiderable in the fpecific gravity of
fpecific gravity ‘ ;
of metals. * Ss d ne Heats ’ SRE RES
gue ichieniical ome compound metals may perhaps be mere mechanical mix
combinations. tures; but Iam inclinedto believe, that by much the greateft num-
ber are true chemical combinations; and confequently, when thefe
laft have been properly formed, a feparation of the component
metals, by the means above-mentioned, can feldom if ever be ef-
fected. C. H. ;
metals,
EXPERIMENTS ON VARIOUS ALLOYS OF GOLD. 159
metals, and does not appear to have been noticed. This is long
continued fri€tion, which always produced a diminution in the
Apecific gravity of the pieces of metal expofed to it.
Among the other lefs powerful caufes which produce fome pale increafes
alteration in the fpecific gravity of gold, the procelles of rolling,
and of annealing, may alfo be enumerated; for, in the bbeefe Annealing di-
of thefe experiments it appeared that the {pecific gravity of me
the bars, &c. was in a fmall degree increafed by rolling, and
that the contrary effect was produced by annealing.
The fpecific gravity of gold, 23 car. 3 grs. fine, when rolled
and ftamped without being annealed, was found to be 19,277 ;
but, when the fame was annealed, the fpecific gravity was
- 19,231, after ftamping.
Mr. H. is however, inclined to believe, that annealing had re-
duced the {pecific gravity to much lefs than is here ftated ; and
_ that the fubfequent operation of {tamping had, in fome meafure,
_ compenfated the effeéts of annealing. For, in the experiments
lately mentioned, it was proved, that the fpecific gravity of
_ the pieces which had not been annealed, was reduced, by long
continued friGtion, from 19,277 to 19,171 ; an effet farpafling
_ that which refulted from annealing by ,060 (19,231—19,171
_ =,060 ;) and, if heat was the caufe, the reverfe might have
_ been expeéted, inafmuch as the annealing heat exceeded that
_ which was produced by friétion ; but, as this was not the cafe,
‘ he is induced to be of opinion, that the {pecific gravity was
; again increafed, by the fubfequent ftamping of the annealed
: pieces.
In addition, eee fora: to thofe caufes of variation in fpecific Caufes of varia-
: tion in fpecific
gravity which are the immediate. confequences of hydroftatical gravity enu-
‘operations, fuch as, the different height of the column of water, merated.
and the changes of temperature to peed it is expofed during
the experiments, the following, as far as they concern metal-
lic fubftances, may be enumerated.
_ 1. Imperfeétions in the interior of the mafs, which are pro-
duced during the proceffes of melting and cafting.
_ 2, The difference of denfity in parts of the fame mafs, re-
fulting from the quality and quantity of the metal, from the
‘nature of the mould, from the more or lefs vertical pofition of
it, and from the height of the column or bar of metal which
is caft.
) 3. ne
160
Abfolute preci-
fion not to be
expected.
Specific gravity
of ftandard gold
of ‘different
kinds.
That of our
ftandard gold
muft occafion-
ally differ.
EXPERIMENTS ON VARIOUS ALLOYS OF GOLD.
3. The unequal diftribution of the metal, or metals, employed
as an alloy, throughout the mafs intended to be alloyed.
4. The. peculiar effeéts which certain metals produce, when
ufed fingly or conjointly as alloys, and which are very different
from the refults of calculation.*
5. Heat, whether produced by friétion or excited in any other
manner.
As, therefore, the fpecific gravity of metals is liable to be in-
fluenced by fuch a variety of caufes, it is almoft in vain to expect
abfolute precifion in the refults of experiments made by different |
perfons; but, at the fame time, it may be obferved, that by
proper care and attention to the above circumftances, a degree
of accuracy may be attained, fufficient to anfwer almoft every
ufefal purpofe, although, from what has been faid, it muft
appear improper to form opinions upon fmall fractional varia-
tions, By the experiments which were made, with every pofhible
precaution, upon feparate and intire ingots of gold, reduced to
ftandard by filver, by filver and copper, and by copper alone, —
when caft in an iron mould like acupel, it appeared, that the
fpecific gravity of each of thefe kinds of ftandard gold is as
follows.
Gold made ftandard by filver - - aio =. Dj92TS
Gold made ftandard by filver and copper - 17,344
Gold made ftandard by copper - = = =‘, 157.)
Now, as our gold coin commonly contains filver as part of the
alloy, and as at different times this proportion of filver muft have |
been various, and even confiderable, particularly when the gold
of Portugal, which is alloyed with filver, was brought to the |
Mint, it naturally follows that, exclufive of the many other
caufes of variation which have lately been enumerated, the fpe-
cific gravity of our ftandard gold muft occafionally be different, :
* There can be no doubt but that the effects of compound alloys —
are, in general, very different from thofe of each metal feparately
confidered ; and that fuch metallic combinations or compound al- }
loys, like neutral falts, and many other compounds, have peculiar
properties, which act varioufly upon the metals to which thefe com= |
pound alloys are added. A great number of accurate experiments —
are, however, requifite to elucidate a queftion fo intricate.
It may here be alfo obferved, that the peculiar properties of com-
pound alloys, prove them to be real chemical combinations. C. H.
according
SPECTRES OCCASIONED BY DISEASE. 161
according to the relative proportions of filver and copper which
compofe the alloy ;* and, as the f{pecific gravity of gold made
{tandard by filver is, in the ingot caft under the above circum-
ftances, 17,927, while that of gold made ftandard by copper is
only 17,157, fo, according to the relative proportions of thefe
two metals, when united in the alloy, the {pecific gravity of the
ftandard gold may vary between the two extremes of 17,927
and 17,157, although the real quality or value of the ftandard
gold remains unchanged; and indeed, when fome allowance is
alfo made for fmall variations arifing from other caufes, the
range of the different fpecific gravities of gold made ftandard
by filver and copper, may be confidered as nearly extending
from 18 to 17. : :
There is much reafon to believe, that the fpecific gravity of SP aay
fine gold has been too highly eftimated; and hence a notion eftimated too
has been too commonly received in this country, which has ae zie
injuricufly and unjuftly been believed on the continent, that tions injurious
the ftandard gold of the prefent reign is inferior to that of the t our coin.
reigns preceding it. But the real faét is precifely the reverfe, Our old coin not
If a few of the old coins have proved better than ftandard, they as aoe
_ were much inferior in the aggregate.
II.
A Memoir on the Appearance of Spectres or Phantoms occafioned
_ by Difeafe, with Pfychological Remarks. Read by Nicouat
to the Royal Society of Berlin, on the 28th of February, 1799.
PartosorHers divide the human being into body and On the philofe-
mind, becaufe the numerous and diftin@ obfervations we make Ee naten
‘on ourfelves oblige us to confider man particularly, as well in and mind.
tefpeét to his corporeal as his mental funétions. Other philofo-
-phers have fuppofed that this fubjeét might be treated with
greater perfpicuity by confidering man as compofed of body,
foul, and mind. There can be no doubt but that thefe, and
even more divifions might be invented. Such philofophers,
* The firft guineas which were coined, or thofe of CHARLEs II;
and James ITI. were generally alloyed with ftandard filver; but the
‘coins of the fubfequent reigns have been alloyed with copper, added
_to compenfate the deficiency of alloy, or of filver in the gold.
Vor. VI.—NovemeBer, 1803, M how-
162
They are of
little ufe,
and quite inac-
Curate.
Speculations on
the nature of
thought are
delufive.
Advantages of
refearche
SPECTRES OCCASIONED BY DISEASE,
however, have by no means confidered that arbitrary fyftematic
divifions, do not conftitute an inveftigation of nature, and that
philofophy often becomes more uncertain the more precifely
we endeavour to diftinguifi and feparate what nature has
clofely united. Sub-divifions in fpeculation feem as neceffary
asfences in fields, both are in themfelves unproduétive, and
the more they are multiplied and extended the greater is the-
diminution of the fertility.
For my part, I will confefs, that I do not 1 where the
corporeal effence in man ceafes, or where the mental begins;
though I admit of the diftinétion, becaufe the extreme differ-
ences can be clearly perceived. If we divide man into three
parts, we fhall be far from removing the difficulties, as we
fhould be were we even to follow thofe modern philofophers,
who regard the thinking fubje@ alone as the real Being (£go,)
and confider all external appearances as confined to the ideas
of confcious beings. The greateft and moft peculiar difficul-
ties in the philofophic knowledge of the human fubjeé confifts
in this, that we have never yet been able clearly and diftinétly
to afcertain the internal aflociation of thofe ftriking differences
which we obferve in our being. Neither the moft fubtil phy-
fiology nor the fineft fpeculative philofophy, have yet been able
to explain the union of thought and phyfical operations. We may
indeed doubt whether the labours of our German philofophers,
though founded jointly upon modern fpeculation and modern
chemiftry, will be attended with any greater fuccefs. Extreme _
caution is moft undoubtedly requifite to prevent our becoming
too intimately and habitually acquainted with certain hypothe- —
tical notions refpeéting things really unknown, foas to miftake
them for truths and deduce erroneous conclufions.
It is much to be feared that the hypothefes and poftulates of
fpeculation will be of little value in this cafe; though to us they —
may feem very confiftent and clear, while we regard them only
ina certain point of view, An attention to experimental proof
may bring us nearer to our aim, though its perfeét accomplifh-
ment will perhaps never be within the reach of human invefti-
gation. Experiments or faéts may fhew the corporeal as well
as the mental funétions in feveral lights, and in fuch as we
never can perceive by mere {peculation,
Though it is truly faid that the firft principles of nature are
p'aced beyond our reach, yet an endeavour to penetrate into
: the
SPECTRES OCCASIONED BY DISEASE. 163
the interior of nature will always prove beneficial to the hu-
man mind ; as long-as we do not prefume to have completely
inveftigated the fubje@; but continue our exertions by uniting
the obfervations of faéts with deliberate reafoning.
Since men have forgotten that what philofophy has fepa- The hypothefis
rated is not on that account feparated in nature, and fince from of ages ca j
the earlieft ages, the mind and body of man have been erties many difquifie.
dered as if diftinét from each other, numberlefs queftions have tions refpeéting
arifen which have given room for much controverfy, without kg
having met with any fatisfattory anfwer. For example: Whe-
ther after the diffolution of the body, the fpirit (or mind) con-
tinues to exift without the body? Whether the fpirit can aé
without the body, and in what manner? And laftly, it is alfo
a queftion, Whether, as we confider a difembodied fpirit not
only in a ftate of feparate continual exiftence, but alfo in a
ftate of continual exiftence and continual a€tion amongft us, a
mere fpirit and its a€tions cannot become perceptible to our
fenfes?—Whether the figure of a fpirit (and im particular that
_ of a deceafed perfon) may not be feen? and, Whether a found
proceeding from it may not affeét the ear of the living? All
the knowledge ufually confidered as poffible to be had of a de-
parted fpirit is confined to feeing and hearing; for as far as
my information extends, the devil is the only {pirit that enjoys
the privilege of affecting the feufe of {mell at his departure.
_ We have lefs motive for difputing about the abfolute Why the nar-
. poffibility of feeing a fpirit, becaufe the idea of a {pirit is fo oe
indiftinét and vague, and becaufe the words fpirit and body in perally con-
confidering man, do in reality indicate mere relative notions, ‘ded to be ime
‘It is inconfiftent with every known law of nature to fuppofe ee
that thofe terms of relation adopted by us folely for the purpofe
of inveftigating the nature of man do themfelves poflefs any
feparate and independent éxiftence. This argument caufes a
fufpicion of deceit or impofition always to attach to narratives
of the apparitions of difembodied fpirits. But thofe who are
inclined to fee and hear fpirits, are net fatisfied with this fum-
mary folution ; they appeal to experience, againft which no
“maxim @ priori can hold. This only is required, that the ex-
' perience mutt be true and well attefted.
Individuals who pretend to have feen and heard fpirits are But thedelufions
not to be perfuaded that their apparitions were fimply the crea- see Se
Weale we
tures of their fenfes. You may tell them of the impofitions acca te ia
. M 2 that veftigated.
164 SPECTRES OCCASIONED BY DISEASE.
that are frequently praétifed, and the fallacy which may lead us
to take a fpirit of our imagination by moon-light for a corpfe.
We are generally advifed to feize the ghofts, in which cafe
it is often found that they are of a very corporeal nature.—
An appeal is alfo made to felf-deception, becaufe many perfons
believe they aétually fee and hear where nothing is either to
be feen or heard. No reafonable man, I think, will ever deny
the poffibility of our being fometimes deceived in this man-
ner by our fancy, if he is in any degree acquainted with the
nature of its operations. Neverthelefs, the lovers of the
marvellous will give no credit to thefe objections, whenever
they are difpofed to confider the phantoms of imagination as
‘ realities. We cannot therefore fufficiently colleét and authen-
ticate fuch proofs as fhew how eafily we are mifled; and with
what delufive facility the imagination can exhibit, not only to de-
ranged perfons, but alfo to thofe who are in the perfeét ufe of © |
their fenfes, fuch forms as are fcarcely to be diftinguifhed from
real objets.
Striking in- I myfelf have experienced an putea ct of this, which not
ances of “PP only in a pfychological, but alfo ina medical point of view ap-
ritions feen by Me PY RHOLOe u Pp P
the author. pears to meof the utmoft importance. I faw, in the full ufe
of my fenfes, and (after I had got the better of the fright which
at firft feized me, and the difagreeable fenfation whieh it
caufed) even in the greateft compofure of mind, for almoft
two months conftantly, and involuntarily, a number of human
and other apparitions;—nay, [even heard their voices;—yet
after all, this was nothing but the confequence of nervous de-
bility, orirritation, or fome unufual ftate of the animal fyftem.
The publication of the cafe in the Journal of Praétical Me-
dicine, by Profeffor Hufeland of Jena, is the caufe of my now
communicating it to the Academy. When I had the pleafure
of {pending a few happy days with that gentleman laft fummer,.
at Pyrmont, I related to him this curious incident.
Bpellye one But as it is probable he might not diftinétly remember that
ties andappa. Which I had told altogether accidentally, perhaps indeed not
citions. very circumftantially, {ome confiderable errors have been ad-
mitted into his narrative. In fuch a cafe, however, it is more
neceflary than in any other, to obferve every thing with
accuracy, and to relate it with fidelity and diftinétnefs. If
iball therefore pafs over nothing which I remember with any
degree of certainty. Several incidents conneéted with the ap-
paritions
SPECTRES OCCASIONED BY DISEASE, 165
paritions feem to me of great importance; though we might Narrative and
be apt to regard them in a fecondary point of view; for we ne as
cannot determine of what confequence evena circumftance of aca by pi 8
the moft trivial nature may be, if at any future period (in cafe indifpofition.
more experiments of a like natureare afcertained) fome fuppo-
fitions or conclufions can be made refpeting the origin of fuch
phantoms, or on fome law of the affociation of ideas accord-
ing to which they are modified or follow one another.
I was alfo, which is feldom the cafe, ina fituation to make
obfervations on myfelf. I took down therefore in a few words
what was moft important, and recounted it immediately to: fe-
veral perfons,. My memory, which is extremely retentive, has
befides treafured up the moft minute circumftances ; the more
on that account, as this ftory has very often proved the fubjeé
of my impartial confideration, not only with regard to my own
particular fituation, but alfo in refpeét to its many’ pfychologi-
cal confequences. Its truth will, I hope, require no further
affurance on my part, fince a member of this academy (Mr.
Selle) is an unexceptionable witnefs of it, having, as my phy-
fician, received a daily account of all that happened to me.
It would be extremely improper in an affembly like the pre-
fent to fpeak much of myfelf; it can only be excufable in this
particular cafe, where it ferves to throw greater light on fci-
entific inveftigation. I muft requeft permiffion therefore to
notice feveral particulars of my fituation previous to my feeing
the phantoms, as thofe incidents may have greatly affected the
ftate of my body and mind during that time.
In the laft ten months of the year 1790, I underwent feveral
very fevere trials, which greatly agitated me. From the month
‘of September in particular, repeated fhocks of misfortune
__ had befallen me, which produced the deepeft forrow. It had
been ufual for me to lofe blood by venefeétion twice a year.
This was done once on the 9th of July 1790, but towards the
clofe of the year it was omitted. In 1783-1 had been fuddenly
feized with a violent giddinefs, which the phyfician imputed
to an obftruétion in the fmall mufcles of the abdomen, proceed-
ing from too intenfe an application to ftudy, and my fedentary
manner of life for many years. Thefe complaints were re-
_ moved by a three years cure, and the rigid obfervance of a
ftri@ diet during that time. In the firft ftage of the malady
_ theapplication of leeches to the anus had been particularly ef-
feétive,
166 SPECTRES OCCASIONED BY DISEASE.
Narrative and feétive, and this remedy I had from that time regularly ap-
pani sat plied twice or thrice a year, whenever I felt congeftion in the
ducedby nervous head. It was on the 1ft of March 1790 that the leeches had
indifpo&tions been laftapplied; the bleeding therefore and the clearing of
the minuter blood-veffels by leeches had, in 1790 been lefs fre-
quently obferved than ufual. A circumftance too that could
not tend to benefit my deplorable fituation was, that from Sep-
tember I had been continually engaged in bufinefs which re-
quired the fevereft exertion, and which, from frequent inter-
ruptions, was rendered ftill more burthenfome and diftreffing.
In the firft two months of the year 1791, I was much af-
fected in my mind by feveral incidents of a very difagreeable
nature; and on the 24th of February a circumftance occurred
which irritated me extremely. At ten o’clock in the forenoon
my wife and another perfon came to confole me; I was in a
violent perturbation of mind, owing to a feries of incidents
which had altogether wounded my moral feelings, and from
which I faw no poffibility of relief; when fuddenly I ob-
ferved at the diftance of ten paces from me a figure,—the fi-
gure of a deceafed perfon. I pointed at it, and afked my wife
whether fhe did not fee it. She faw nothing, but being much
alarmed, endeavoured to compofe me, and fent for the phyfi-
cian. The figure remained fome feven or eight minutes, and
at length I became a little more calm; and as I was extremely
exhaufted, I foon afterwards fell into a troubled kind of flum-
ber, which lafted for half an hour. The vifion was afcribed
to the great agitation of mind in which I had been, and it was
fuppofed I fhould have nothing more to apprehend from that
caufe; but the violent affection had put my nerves into fome
unnatural ftate, from this arofe further conleqheree which
require a more detailed defcription.
In the afternoon, a little after four o’clock, the figure which
I had feen in the morning again appeared. I was alone when
thishappened ; eeuctaaliodee which, as may be eafily¢onceived,
could not be very agreeable. I went therefore to the apart-
ment of my wife, to whom I related it. But thither alfo the
figure purfued me. Sometimes it was prefent, fometimes it
vanifhed, but it was always the fame ftanding figure. A little
after fix o’clock feveral ftalking figures alfo appeared; but they
had no conneétion with the ftanding figure. I can affign no
other reafon for this apparition than that, though much more
compofed
SPECTRES OCCASIONED BY DISEASE, 167
compofed in my mind, I had not been able fo foon entirely to Narrative and
forget the caufe of {uch deep and diftreffing vexation, and had remarks on
reflected on the confequences of it, in order, if poffible, to ssed ae al
avoid them; and that this happened three hours after dinner, imagination.
at the time when the digeftion juft begins.
At length I became more compofed with refpeé to the dif-
agreeable incident which had given rife to the firft apparition;
but though I had ufed very excellent medicines, and found my-
felf in other refpeéts perfeétly well, yet the apparitions did
not diminifh, but on the contrary rather encreafed in number,
_and were transformed in the moft extraordinary manner.
_ After [ had recovered from the firft impreffion of terror, I
never felt myfelf particularly agitated by thefe apparitions, as
I confidered them to be what they really were, the extraordi-
nary confequences of indifpofition; on the contrary, I endea-
voured as muchas poffible to preferve my compofure of mind,
that I might remain diftinétly confcious of what paffed within
me. I obferved thefe phantoms with great accuracy, and very
often reflected on my previous thoughts, with a view to difcover
fome law in the affociation of ideas: by which exa@ly thefe or
‘other figures might prefent themfelves to the imagination. —
. Sometimes I thought I had made a difcovery, efpecially in the
latter period of my vifions; but on the whole I could trace no
connexion which the various figures that thus appeared and
difappeared to my fight had, either with my ftate of mind, or
with my employment, and the other thoughts which engaged
my attention. After frequent accurate obfervations on the
fubjeé&, having fairly proved and maturely confidered it, I
could form no other conclufion on the caufe and confequence *
of fuch apparitions than that, when the nervous fyftem is weak
and at the fame time too much excited, or rather deranged,
fimilar figures may appear in fuch a manner as if they were ac-
tually feen and heard; for thefe vifions in my cafe were not the
_ confequence of any known law of reafon, of the imagination,
or of the otherwife ufual affociation of ideas; and fuch alfo is
the cafe with other men, as far as we can reafon from the few
examples we know.
The origin of the individual pictures which prefent
themfelves to us, muft undoubtedly be fought for in the
ftru€ture of that organization by which we think; but this will
always.
168 SPECTRES OCCASIONED BY DISEASE.
Narrative and always remain no lefs inexplicable to us than the origin of
remarks on thofe powersby which confcioufnefs and fancy are made to exift.
Pei aybs The figure of the deceafed perfon never appeared to me
indifpofition. after the firft dreadful day; but feveral other figures fhewed
themfelves afterwards very diftin@ly; fometimes fuch as I
knew, moftly, however, of perfons I did not know, and
amongft thofe known to me, were the femblances of both
living and deceafed perfons, but moftly the former: and I made
the obfervation that acquaintance with whom I daily converfed
never appeared to me as phantafms; it was always fuch as
were at a diftance. When thefe apparitions had continued
fome weeks, and I could regard them with the greateft com-
pofure, I afterwards endeavoured, at my own pleafure to call
forth phantoms of feveral acquaintance, whom I for that rea-
fon reprefented to my imagination in the moft lively manner,
but ‘in vain.—For however accurately I pi€tured to my mind
the figures of fuch perfons, I never once could fucceed in my
defire of feeing them externally; though I had fome fhort time
before feen them as phantoms, and they had perhaps after-
wards unexpectedly prefented themfelves to me in the fame
manner. The phantafms appeared to me in every cafe invo-
luntarily, as if they had been prefented externally, like the
phenomena in nature, though they certainly had their origin
internally; and at the fame time I was always able to diftin-
guifh with the greateft precifion phantafms from phenomena.
Indeed, I never once erred in this, as ] was in general per-
feétly calm and felf-colleéted on the occafion. I knew ex-
tremely well, when it only appeared to me that the door was
opened, and a phantom entered, and when the door really
was opened and any perfon came in.
It is alfo to be noted, that thefe figures appeared to me at
all times, and under the moft different circumftances, equally -
diftinét and clear. Whether I was alone, or in company,
by broad day-light equally as in the night time, in my own as
well as in my neighbour’s houfe; yet when I was at ano-
ther perfon’s houfe, they were lefs frequent, and when I
walked the public {treet they very feldom appeared. When
I thut my eyes fometimes the figures difappeared, fometimes
they remained even after I had clofed them. If they vanifhed
in the former cafe, on opening my eyes again, nearly the
fame figures appeared which I had feen before,
I fome-
SPECTRES OCC'ASIONED BY DISEASE. 169
I fometimes converfed with my phyfician and my wife, con- Narrative and
cerning the phantafms which at the time hovered around me} pepe set
for in general the forms appeared oftener in motion than at duced by nervous
reft, ' They did not always continue prefent—they frequently indifpofition.
left me altogether, and again appeared for a fhort or longer
{pace of time, fingly or more at once; but, in general, fe-
veral appeared together. For the moft part J faw human
figures of both fexes; they commonly paffed to and fro as if
they had no conneétion with each other, like people at a fair
‘where allis buftle; fometimes they appeared to have bufinefs
with one another. Once or twice I faw amongft them per-
fons on horfeback, and dogs and birds; thefe figures all ap-
peared to me in their natural fize, as diftinctly as if they
had exifted in real life, with the feveral tints on the unco-
vered parts of the body, and with all the different kinds and
colours of clothes, But I think, however, that the colours
were fomewhat paler than they are in nature.
None of the figures had any diftinguifhing charaéteriftick,
they were neither terrible, ludicrous, nor repulfive; moft of
them were ordinary in their appearance,—fome were even
agreeable.
On the whole, the longer I continued in this ftate, the
more did the number of phantafms encreafe, and the appa-
titions became more frequent. ‘ About four weeks afterwards
I began to hear them {peak : fometimes the phantafms {poke
-with one another ; but for the moft part they addrefled them-
felves to me: thefe {peeches were in general fhort, and never
contained any thing difagreeable. Intelligent and refpeéted
friends often appeared to me, who endeavoured to confole me
in my grief, which {till left deep traces on my mind. This
{peaking I heard moft frequently when I was alone: though
I fometimes heard it in company, intermixed with the con-
verfation of real perfons; frequently in fingle phrafes only, —
-but fometimes even in connected difcourfe.
Though at this time I enjoyed rather a good ftate of health
both in body and mind, and had become fo very familiar with
thefe phantafms, that at laft they did not excite the leaft dif-
agreeable emotion, but on the contrary afforded me frequent
fubjeéts for amufement and mirth; yet as the diforder fenfibly
_ encreafed, and the figures appeared to me for whole days to-
gether, and even during the night, if I happened to awake,
I I had
170
SPECTRES OCCASIONED BY DISEAS&,
Narrative and J had recourfe to feveral medicines, and was at laft again
remarks on
{pectres pro-
obliged to have recourfe to the application of leeches to the
duced by nervous anus.
indifpofition.
This was performed on the 20th of April at eleven o ‘clock
in the forenoon. I was alone with the furgeon, but during
the operation, the room {warmed with human forms of every
defcription, which crouded faft one on another ; this continued
till half paft four o’clock, exaétly the time when the digeftion
commences. I then obferved that the figures began to move
more flowly; foon afterwards the colours became gradually
paler; every feven minutes they loft more and more of their
intenfity, without any alteration in the diftinét figure of the
apparitions. At about half paft fix o’clock all the figures
were entirely white, and moved very little; yet the forms
appeared perfeétly diftinét; by degrees they became vifibly
lefs plain, without decreafing in number, as had often formerly
been the cafe. The figures did not move off, neither did they
vanifh which alfo had ufuaily happened on other occafions.
In this inftance they diffolved immediately into air; of fome
even whole pieces remained for a length of time, which alfo
by degrees were loft to the eye. At about eight o’clock there
did not remain a veftige of any of them, and I have never
fince experienced any appearance of the fame kind. Twice
or thrice fince that time I have felt a propenfity, if I may be
- fo allowed to exprefs myfelf, or a fenfation as if I faw fome-
thing which in a moment again was gone. -I was even fur-
prifed by this fenfation whilft writing the prefent account,
having, in order to render it more accurate, perufed the papers
of 1791, and recalled to my memory all the circumftances of
that time, So little are we fometimes, even in the greateft
compofure of mind, mafters of our imagination.
This is an exaét narrative of the apparitions which I ob-
ferved during tbe difordered ftate of my nerves: andI fhall
now add a few obfervations, partly with the intention of ex-
plaining their origin from other obfervations made on myfelf,
and partly with a view of pointing out at leaft fome diftant
pfychological confequences, which might be deduced from this
remarkable cafe.
Experience fhews that we may, in various manners, ima-
gine that we fee figures, and even hear them when they do
not really exift.
It
SPECTRES OCCASIONED BY DISEASE. 171
‘it. And commonly this may happen in dreams.—The Narrative and
manner of dreaming is different in every individual, and pro- SPH gs
es \ i pectres pro-
bably depends on the joint effeéts of the powers of intelleét, duced by nervous. |
and thofe by which the impreffions of the fenfes are received, indifpofition.
and thefe are modified by the ftate of the fyftem at each par-
ticular time. I have myfelf made fome remarkable obferva-
tions on the nature of my dreams, and compared them with
fome obfervations on that fubjeét which have been commu-
nicated to me by others.
2d. Inevery degree of mental derangement till abfolute
infanity.
_ 3d. In fevers of the brain, which for a fhort time, or at
certain intermitting periods, occafion a delirium.
4th. By the mere power of imagination without any fever,
when in other refpeéts the judgment is perfeétly found. In _
this cafe it is very difficult to difcover the truth, unlefs we
combine an accurate habit of obfervation with the moft ime
partial ferutiny.
Inftances are too frequent in which we are impofed upon,
not by the imagination, but by delufion of the judgment.
How many are there, who prefer the marvellous and aflume
an air of importance, when they have an opportunity of re-
lating wonderful things of themfelves—How few are there
‘who endeavour to diveft themfelves of prejudice, or to check
their imagination ; and ftill fewer are they who are accurate
in their obfervations, efpecially in fuch as relate to them-
felves; even thofe who have fufficient firmnefs to adhere
ftri€tly to the truth form an inconfiderable number. Hence
it is, that when a perfon relates any ftrange incident, he
either detracts or magnifies, and will even fancy that he has
verified fome facts, which he has invented only at the mo-
ment that he relates them. This laft is the cafe with a clafs
of men who obftinately perfift in their own opinions, and fre-
_ quently affert more than they can fupport, merely with a
view to maintain what they have once advanced. All the
above mentioned circumftances feem to have coincided in the
celebrated vifions of Emanuel Swedenborg. He delighted in
fpeculation and myftical theology ; he had formed a fyftem
_ for himfelf in which ghofts were neceffary, and it was his
primary view to eftablifh this wonderful fyftem. It is pof-
fibie that he may have feen phantafms, the more fo as he
ftudied
172 SPECTRES OCCASIONED BY DISEASE.
Narrative and ftudied much, and was a great eater.* But in order to
ieotaee: appear a prodigy to the world, he embellifhed his vifions
duced by nervouson which he wrote voluminous treatifes, by creating new
indifpofition, images in conformity with his own fyftem.
Laftly, thofe who are moft converfant with the marvellous,
give but a very indiftin€ idea of their vifions. This I have
found in converfation with perfons who in other refpeéts were
very worthy characters, but who were great admirers of the
what are termed occult fciences, which they cultivated to
fuch a degree, that to give you a notion of it here would
feem prepofterous. I have frequently difcourfed on fpirits,
and the feeing of fpirits, with a perfon who ranked very high
in the fchool of fecret wifdom, but who was otherwife a man
of a very limited capacity, and rather ignorant in all thofe
fciences which enlighten the mind. This perfon told me
amongft other things that he fhould feel very unhappy, were
he not continually in company with fpirits. As I have al-
ways taken a pleafure in the clear developement of human
opinions, however abfurd they may appear, I was defirous to
learn in what manner he faw the fpirits, and how he came
into company with them ?—But here he would not allow of the
appearance of any corporeal forms; he affured me that fpirits
were only to be feen with the eyes of the fpirit ; then he added
in a very ferious tone, “‘ Juft as the human foul is Naephaefch,
‘* ora branch taken off the tree, fo are all fpirits branched off
“from the fupreme bie as it in the aftringent motion com-
ss preffed its being.” On nearer enquiry I could eafily per-
ceive that he entertained a confufed notion of the cabaliftick
ontology of Spinoza, and that he imagined all the powers in
nature to be fpirits. What he meant to fay therefore, was
neither more nor Jefs than that he fhould feel unhappy, did he
live in a world where nature was perfeétly inanimate; if he
could not think that every thing around him was in the con-
tinual and mutual exerci/e of its powers. In this belief then
he peopled all {pace with fpirits, nearly in the fame manner
as the antient mythology peopled the woods with Dryads and
* On this fubjeét, the review of Swedenborg’s Works in the Al-
gemzine Deut{che Bibliothek, vol. 107, p. 15, is very interefting.
In it the refemblance of Swedenborg’s fyftem, with the vifions of
the German enthufiaft, Johann Tennhart, is clearly accounted for :
he alfo was a great eater.
4 Hama-
SPECTRES OCCASIONED BY DISEASE. 173
Hamadryads, Indeed, every thing properly confidered, the Narrative and
opinion of my cabalift is not quite fo very abfurd as you may femarks sn
fuppofe ; for in reality, the word power is with the philofopher eae Jus
> ’ t s y nervous
only that which the x is to the mathematician ; and, if I be indifpofition.
not altogether miftaken, the mathematician can with his x,
bring more clear truths to light, than the philofopher by the
word power, Ifa given power cannot be rendered fubfervient
to deduétion, fo that, like Newton’s calculus, it fhall perfeétly
accord with experience; nothing more will be determined or
explained by the mere word power, than by the word {pirit; and
I doubt much whether the new judicious Kantian fyftem of
Dynamic natural philofophy, which confiders all bodies as
mere aggregates of powers, would not rather cut the gor-
dian knot than unravel it.
It is not very uncommon that by a derangement of the
corporeal powers, even without infanity and inflammatory
fevers. apparitions do ftrike the eye externally, which are
only internally the produétion of the imagination. The expe-
rience of this may teach usa leffon of forbearance, not rafhly to
confider as impoftors thofe well difpofed perfons who believe
they have feen apparitions. But as manifold experience fhews
us how far the human imagination can go in the external
reprefentation of piétures; it may alfo admonith thofe well-
difpofed perfons not to afcribe to their vifions any degree of
reality, and ftill lefs to confider the effeéts of a difordered
- fyftem, as proofs that they are haunted by {pirits. .
The celebrated Juftus Mofer frequently believed that he
faw flowers, Another of my acquaintance fees in like man-
ner, at times, mathematical figures, circles, fquares, &c.
in different colours. More examples of this kind may per-
haps be found in Moretz’s Magazine, in Krueger’s Expe-
rimental Pfychology, and in Bonnet’s Pfychological writings.
The hearing of founds is a cafe which feldomer occurs. My
much-lamented friend Mofes Meudeljohn had, in the year
1792, by too intenfe an application to ftudy, contracted a
malady, which alfo abounded with particular pfychological
apparitions. For upwards of two years he was incapacitated
from doing any thing ; he could neither read nor think, and
was rendered utterly incapable of fupporting any loud noife.
If any one talked to him rather in a lively manner, or if he
himfelf happened to be difpofed to lively converfation, he
Gigad fell
174
Narrative and
remarks on
fpectres produ-
ced by nervous
indifpofition.
SPECTRES OCCASIONED BY DISEASE.
fell in the evening into a very alarming {pecies of catalepfis;
in which he faw and heard every thing that paffed around
him, without being able to move a limb. If he had heard any
lively converfation during the day, a ftentorian voice re-
peated to him while in the fit, the particular words or fylla-
bles that had been pronounced with an impreffive accent, or
loud emphatic tone, and in fuch a manner that his ears re-
verberate.
Seldom as it may happen, that perfons believe they fee
human forms, yet examples of the cafe are not wanting.
A refpeétable member of this academy, diftinguifhed by his
merit in the fcience of botany, whofe truth and credibility
are unexceptionable, once faw in this very room in which
we are now aflembled, the phantafm of the late prefident
Maupertuis. A perfon of a found and unprejudiced mind,
though not a man of letters, whom I know well, and whofe
word may be credited, related to me the following cafe. As he
was recovering from a violent nervous fever, being ftill very
weak, he lay one night in bed perfeétly confcious that he
was awake, when the door feemed to open, and the figure of a
woman entered, who advanced to his. bed-fide. He looked
at it for fome moments, but as the fight was difagreeable, he
turned himfelf and awakened his wife ; on turning again how-
ever he found the figure was gone. But out of many cafes I
have never known an inftance like my own, in which any per-
fon had for almoft two months conftantly beheld fuch vifionary
forms, and feemed even to have heard them; except it was
that of two young ladies, who, as I have been credibly in-
formed, frequently faw appearances of this nature.
Iam by no means infenfible to a certain feeling which ad-
monifhes me of the impropriety of talking fo much of myfelf
in an affembly like this; but fince I tranfgrefs only with a fci-
entific intention, to contribute to the knowledge of the effeéts
of the human imagination, I muft endeavour to fupprefs this
feeling. I may look for pardon, I truft, from thofe who know
and refpeét every thing which tends to enlarge the ftock of
human knowledge, even if I fpeak more of myfelf. For,
when I proceed to defcribe the ftate of my imagination, and the
nature of the apparitions during a previous malady, it will be
merely with an intention to fhew the apparitions which form
the fubje& of this le€ture in a lefs wonderful point of view,
and
SPECTRES OCCASIONED BY DISEASE. 175
and by that means perhaps to contribute in fome degree to the Narrative and
illuftration of fo ftrange an incident. fein
_I muft obferve that my imagination poffeffes in general a duced by nervous
great facility in pi€turing. I have for example fketched in indifpofition,
my mind a number of plans for novels and plays; though I
have committed very few of them to paper, becaufe I was
lefs folicitous to execute than to invent. I have generally
arranged thefe outlines when, in. a chearful ftate of mind.
I have taken a folitary walk, or when travelling I have fat in
my Carriage, and could only find employment in myfelf and
my imagination. Conftantly and even now do the different
perfons whom I imagine in the formation of fuch a plot, pre-
fent themfelves to me in the moft lively and diftin& manner ;
their figure, their features, their manner, their drefs, and
their complexion, are all vifible to my fancy. As long as I
meditate on a fixed plan, and afterwards carry it into effet, —
even when I am often interrupted, and muft begin it again
at different times, all the aéting perfons continue prefent in
the very fame form in which my imagination at firft produced
them. I find myfelf frequently in a ftate betwixt. fleep-
ing and waking, in which a number of piétures of every
defcription, often the ftrangeft forms, thew themfelves, change
and vanifh. In the year 1778, I was afflicted with a bilious
fever, which, at times, though feldom, became fo high as
to produce delirium, Every day towards evening, the fever
came on, and if I happened to fhut my eyes at that time, I
could perceive that the cold fit of the fever was beginning
even before. the fenfation of cold was obfervable. This I
knew by the diftin@ appearance of coloured pictures of lefs
than half their natural fize, which looked as if in frames.
‘They were a fet of land{capes compofed of trees, rocks, and
other objeéts. If I kept my eyes fhut, every minute fome al-
teration took place in the reprefentation. Some figures va-
nifhed, and others appeared. But if I.opened my eyes all
was gone ; if I fhut them again J had quite a.different land-
“Aecape. This cafe was therefore entirely different from what
_ afterwards in the year 1791, when the figure remained un-
changed during the opening and fhutting of the eyes. In
{the cold fit of the fever I fometimes opened and fhut my
eyes every fecond for the purpofe of obfervation, and every
time a different pi€ture appeared. replete with various ob-
jes
176
SPECTRES OCCASIONED BY DISEASE.
Narrative and jeéts which had not the leaft refemblance with thofe that ap-
remarks on
{pectres pro-
peared before. Thefe piétures prefented themfelves without
duced bynervous interruption, as long as the cold fit of the fever lafted. They
indifpofition.
became fainter as foon as I began to grow warm, and when
I was perfectly fo, all were gone. When the cold fit of the
fever was entirely paft, no more piétures appeared; but if
on the next day I could again fee pi€tures when my eyes were
fhut, it was a certain fign that the cold fit was coming on.
I muft further obferve, that when I either think deeply on
a fubjeé, or write attentively, particularly when I have exert-
ed myfelf for fome time, a thought frequently offers itfelf
which has no connection with the work before me, and this
at times in a manner fo very lively, that it feems as if ex-
preffed in aétual words.
Thisnatural vivacity of imagination renders it lefs wonder-
ful, that after a violent commotion of mind, a number of
delufive pi€tures fhould appear for feveral weeks in fucceffion.
Their leaving me on the application of leeches, fhews clearly
that fome anomaly in the circulation of the blood was con-
nected with the appearance of thofe phantafms; though it
may perhaps be too hafty a conclufion to feek for their caufe
in that alone. It feems likewife remarkable, that the be-
ginning of the apparitions, after. the difturbance in my mind
was fettled, as well.as the alteration which took place when |
they finally left me, happened exaétly at the time when
digeftion commenced. It is no lefs remarkable, that the ap-
paritions before they entirely ceafed, loft their intenfity of
colours; and that they did not vanifh or change as formerly,
but feemed gradually to diffolve into air.
Had I not been able to diftinguith phantafms from pheno-
mena, I muft have been infane. -Had I been fanatic or fu-
perftitious, I fhould have been terrified at my own phantafms,
and probably might have been feized with fome alarming
diforder. Had I been attached to the marvellous, I fhould
have fought to magnify my own importance, by afferting that
I had feen fpirits ; and who could have difputed the faéts with
me? The year 1791 would perhaps have been the time to
have given importance to thefe apparitions, In this cafe
however, the advantage of found philofophy, and deisberate
obfervation may be feen. Both prevented me from becoming
either a lunatic or an enthnfiaft; with nerves fo ftrongly ex-
| cited
SPECTRES OCCASIONED BY DISEASE; 177
cited; and blood fo quick in circulation, either misfortune Narrative and
might have eafily befallen me. But I confidered the phan- remarks on
tafms that hovered around. me as what they really were phe A
2 duced by nervous
namely, the effects of difeafe; and made them fubfervient to indifpofition.
my obfervations, becaufe I confider obfervation and refle@ion
as the bafis of all rational philofophy.
Our modern German philofophers, will not allow that
obfervation ought to be admitted in theoretical philofophy.
Hence arofe Kants’ Tranfcendental Idealifm, which at laft
degenerated into the grofs enthufiaftic idealifm; which is
found in Fichte’s writings. This philofopher confiders all
external objects as our own produdtions. “ What we con-
“* fider as things independent of us are,” according to him,
“no more than our own creatures, which we fear, admire
“‘ and defire ; we believe our fate to be dependerit on a
* fhadow, which the fingle breath of a free being might
* deftroy.”” Thefe are Mr. Fichte’s own words *.
The mere pigture in the mind, without external experience,
would never be fnfficient to afford us a convincing proof;
whether we faw phenomena or phantafms. The critical
philofophers maintain, that knowledge deduced from obferva-
tion is merely empirick, and therefore not to be depended on;
it is perhaps true that nature has affigned us no greater
certainty than this refpeéting our ideas. But could we be truly
confcious of our grounds of reafon, if the appearances called
external, which follow laws that do not depend on the re-
prefentations in our mind, did not continually agree with thofe
reprefentations ? Are we poffeffed of any other criterion?
Does not the great theoretical philofopher, when he fees
_ every thing yellow, conclude that his eye is jaundieed ; or
_ when every thing appears black to him, that his brain is
_ affeGted? In thefe cafes he does not truft his imagination or
_ mental powers alone.
I may here apply the confideration of the illufions which
I witneffed. I am well aware that no general conclufions
can be drawn from a fingle inftance ; but ftill the experience
_ Of a fingle cafe, if accurately obferved and faithfully defcribed,
is fufficient to deftroy hypothefes which have too long been
_ honoured with the name of fyftems.
Ae
tei
tee er
* Fichte’s Appeal; p. 44.
Vor. VI.—Novemser, 1803. N _ According
aes
178 SPECTRES OCCASIONED BY DISEASE,
Narrative and According to Fichte, fince during the fituation I have above
remarks on : 4 Sip
fpe€tres pro- deferibed, I was in other refpeéts in the perfeét ufe of my
duced by nérvous reafon, as well as the perfons who were really about me; as
indifpofition. ce : .
the apparitions which I faw, as well as thofe which are con-
fidered as realities, were the one as well as the other, my
own produétions:—Why then were my creatures of both
kinds fo effentially different ?
My judgment fhewed me this plainly, by conclutions
founded on the previous courfe of obfervations. The greateft
modern idealifts who depend fo much on the confufion in
which they have involved themfelves by the fuppofed depth
of their fpeculations, will certainly never pretend that both
perceptions were of the fame nature; fince if fo, T could
not have inveftigated their difference? But by what means
could this be done? I obferved that real perfons followed in a
determinate order, by external laws that do not depend on
me, inan order that I myfelf muft continually follow, as was
evident from my fenfe of confcioufnefs. I could alfo lay hold
_ of the real objets, as well as of myfelf. Neither of thefe
circumftances was, however, the cafe with the phantafms ;
I had always found it fo in the conftant obfervation of my elf,
of the apparitions without me, and in my own confcioufnefs.
The phantafms, as well as the phenomena, no doubt, lay in
my mind; but I am neceffarily compelled to afcribe to the latter,
the fame reality which I am obliged to afcribe'to myfelf; viz.
fomething that does not lie in my mind alone; fomething that
alfo exitts without my mind; fomething independent of my
con{cioufnels, which determines the nature of my idea 5
fomething which we formerly ufed to call the thing itjélf, ‘be-
fore the critical philofophy fo unjuftly reprobated this unex-
ceptionable term. On the contrary, however, I could ‘not
a{fcribe this fame reality to the illufion ; I could form no other
eonclufion, than that they originated in my internal confciouf- ;
nefs alone; in a confcioufnefs which was alfo difordered, ~
as I might juftly conclude from the obfervations I made on —
myfelf. I repeat, that both the phenomena and the phan- ~
tafms exifted in my mind: if I had not been able to diftinguifh —
between them, I muft have been infane. By what means |
could I diftinguifh, if I did not attribute reality to the |
former ;—and that they poffeffed reality, Iinferred from ob-
fervations
frequently collected on the fhores of the Ifland of Maragnan,
ANALYSIS OF AMBERGRIS; : 179
fervations to which I am fill inclined to give confidence,
until Mr. Fichte can more clearly convince me that it ought -
in no cafe to be depended on.
[ES SO I SR TES I >
| Il.
Analyfis of Ambergris ; by Cit. Bourtton La Grance*,
\
Iv: is an opinion now generally adopted, that ambergris is Ambergite fod
formed in the ftomach of the cachalot, or fpermaceti whale, \ ie hye
phyfeter macrocephalus, and appears to be a produét of its iiderece plates
digeftive faculties.
tr, Swediaur has fhewn, in his inquiries into the. nature Beaks of cuttle-
and origin of ambergris, that the beaks of the cuttlefifh, in- a a iy all
terfperfed throughout all the large pieces of ambergris, that me Efe
are found fwimming on the fea, or caft upon the. fhore, as
well as thofe extraéted from the bellies of whales, belong to
the fpecies called by Linneus fepia oftopodia. The exiftence
of thefe beaks and other foreign f{ubftances in ambergris
evidently proves it to have been originally in a foft or fluid whence it muf
fiate. Dr. Swediaur afferts, that the whale, in the belly Beg cad nae
which ambergris is found, is the fame fpecies as that from The fpermaceti
whale that
which ect 3 is extracted, which appears to be the phy/éter é
produces its
macrocephalus of Linneus ; and feeds chiefly on the large fpecies ©
of cuttlefith., The ambergris is found in the inteftinal canal
of this fifh; it is a fource of difeafe to it +; and after it iffues Occafionsa
from the cavity in which it had been included, it gradually oat te the
acquires the folidity it is known to poffels. lid eee
Ambergris is found in the Indian Seas, near the Moluccas, exclufion.
Found on the
~ Maldivia Ifiands, and Madagafcar, on the coafts of China ,,.¢5 ofthe
and Japan, and from Jolo to the Philippine Iflands. It is Indian Ocean
and its iftandss
or of Brazil; but more commonly on thofe of Africa, toward Of Brazil,
cape Blanco, the gulf of Arguin, the bay of Portendie, and nd alfo of
Africas
on fome other Iands, that extend from Mofambique to the aay
# Red Sea.
% Annales de Chimie, No. 139. or XLVII. 68.
4 Is it not rather the effe&, than the caufe of difeafe? J.C.
N 2 From
180
The inhabitants
ef the Samballas
feek for iton the
fhore after
ftorms by the
{mell.
Certain birds
and other
animals fond of
t.
Certainly a
vegetable pro-
dudtion.
Excrements of
fome animals,
particularly of
the ox and pig,
refemble it in
fmell.
Cowdung called
in fome places
Native mufk.
External quali-
ties of amber
gris.
Its odour more
powerful as it
grows old, or
when mixed
with other per-
fumes.
Marks of good
ambergris.
The older che-
mitts claffed it
among the bitu-
mens,
Geoffroy’s
analyfis of it b
alcohol,
and by diftilla-
tion,
ANALYSIS OF AMBERGRIS.
From the accounts of various travellers, the inhabitants of
the Samballas feek for it in a fingular manner: they hunt it by
fcent. After a ftorm they run along the fhore, and if any
ambergris be thrown up, they findit by the {mell. There are
certain birds and other animals on thofe coafts, that are very
fond of ambergris, and, attraéted from a diftance by its {mell,
they fearch for it to eat.
There is no doubt, that ambergris is a vegetable produétion.
Many fubftances refemble it greatly in fmell, fuch as the ex-
crements of mammiferous animals, particularly thofe of the
ox and the pig. I have found, that cowdung dried in the fun,
has a fmell much like that of ambergris, and even of mufk,
whence in fome countries this fubftance, fo prepared, has re-
ceived the name of native mufk.
Ambergris, ambra grifea, isa light fubftance, fwimming on
water, folid, opaque, of an afhen gray colour ftreaked with
white and yellowith brown, flightly odoriferous, its odour dif-
playing itfelf more as it grows old, or when it is mixed with
mufk or other aromata, as is done in preparing perfumes or
odoriferous waters, ;
In its natural ftate good ambergris is known by adhering like
wax to the edge of a knife with which it is fcraped, retaining
the impreffion of the teeth or nails, and emitting a fat odori-
ferous liquid on being penetrated with a hot needle. Though
folid, and in general brittle, it is not hard enough to take a
polith; but on rubbing it with the nail it becomes as fmooth
as hard foap.
Geoffroy, Neumann, Grim, and Brow, have claffed am-
bergris among the bitumens. ‘The analyfis made of it by thefe
chemifts was inadequate to determine its nature. Ambergris,
fays Geoffroy, melts into a refin of a yellow or gold colour ;
kindles, and burns with flame, Spirit of wine does not diffolve
itentirely; a black fubftance like pitch being left, on which
it does not aét. When it is diffolved, it lets fall after fome
time a white cloudy fediment, which gradually coagulates,
and grows thicker and thicker. This coagulum, on drying,
changes to a fhining foliated earth, nowife different from
{permaceti.
On diftillation, according to the fame chemift, ambergris
yields at firft an infipid phlegm, then an acid fpirit or liquor
and
ANALYSIS OF AMBERGRIS.. 18]
and a very odoriferous yellow oil, with a fmall portion of a
volatile acidofaline falt ; and laftly, a fhining black bituminous
fubftance remains at the bottom of the retort. Hence we Thisanalyfis ine
fee this analyfis, which does not differ from thofe related by isiest-
all other chemifts, requires to be revifed, in order to give us
determinate ideas of the nature of this fingular fubftance.
It is perhaps neceflary to apprife thofe, who wifh to repeat Neceffary to be
thefe experiments, that they fhould pay great attention to the itis >)
choice of the ambergris. Many varieties are found in the Many varieties
fhops, the different kinds of which are diftinguifhed by their of itm the thops
price. No doubt this fubftance is fabricated, as caftor is
in fome parts of Germany. Bayen affured me, that he had Fabricated by
feen it made at Frankfort; and it is well known that this 2% 28 Bayes
: : faw at Frankfort
father of chemiftry faw clearly, and that his memory was not apt
to deceive him; and, what is very rare among travellers, that
he never told a lie.
I have examined feveral fpecimens of the ambergris of the Differences of
fhops: fome varied in fpecific gravity, were more or lefs deep thefe varieties,
in colour, had very httle fmell, and were flexible ; others were
of an afhen gray colour, and tolerably hard; and fome were
almoft ftony, fcarcely at all foluble in alcohol, and void of
fmell. |
The ambergris I analyfed was not purchafed from the fhops;
and, on comparing it with that in the cabinet of the Mufeum,
I could find no difference, either in colour or in {mell.
Phyfical Properties.
It is of an afhen gray colour, internally variegated with a Its colour, fmell,
few yellow ftreaks, of a fweet and pleafing fmell, foftening texture,
between the fingers; when reduced to a fine powder it is of
a deeper colour; pounded in a glafs mortar it agglutinates,
and adheres to the peftle.
-Of a flat and almoft infipid tafte, exhibiting the fame ap- tafte,
pearances as wax when chewed between the teeth.
Its fpecific gravity is to that of water as 844 or 849 to fpecific gravity.
1000.
According to Briffon, the fpecific gravity of ambergris is
9263; the weight of the French cubic inch, 4gros 58 grs.; that
of the cubic foot, 64 Ibs. 140z. 3 gr. 47 grs. *
* The fpecimens of ambergris, on which Briffon made his ex-
periments, were taken from the king’s collection,
The
\
182 ANALYSIS OF AMBERGRIS.
The fpecific gravity of the blackifh gray ambergris 7803 ;
the weight of the cubic inch, 4 gros 3 grs.; that of the cubic
foot, 541bs. 9 oz. 7 gr. 35 grs.
Chemical Properties.
Ttburns entirely Experiment I. Ambergris burns, and is entirely diffipated,
Hh al when placed on a red hot coal. It leaves behind an agreeable
fmell.
Melts with alefs If the combuftion be conduéted more flowly, in a crucible
dss ated platina, the ambergris melts, diffufing the fame f{mell.
The fmell of a fatty fubftance may be diftinguifhed like-
wife,
Nothing remains in the crucible, but a-greafy black fpot.,
and is then a 50° of Reaumur’s thermometer are fufficient to melt it, and
fhining brown s ee :
@uid. _ a fhinmg brown-fluid is thus obtained,
Becomes volatile At 80° it is volatilized im the form of a white vapour.
ih ths ‘aj. Exp. Il. The fmell perceived ‘during its volatilization
catesan acid. having led me to fufpeét the prefence of an acid analogous to
that of balfams, an experiment was made to afcertain this.
a oe eae A bit of ambergris was placed in a china capfule, covered
porating it under With a bell, in which was fufpended fome litmus paper.
a bell, This apparatus being placed on a fand-heat, the temperature
was railed fufficiently to volatilize the ambergris, and the
paper was very quickly reddened. Nothing now remained
but to determine the nature of the acid; and for this purpofe
_ and proved to be Schelee’s procefs for extra@ting the acid of Benjamin was
the benzoic,
adopted.
The produét was examined, and left no doubt of their
analogy.
On diftillation, Exp, III. The analyiis by diflillation in a retort added
nothing to the knowledge we already poffefled of the nature
of ambergris.
it gives out a A gentle heat melted it: on raifing the fire it was decom-
Ee teihia pofed, and there pafied over into the receiver a whitifh acid
light oil, and liquor with a white oil, partly foluble in alcohol, which gave
ash abulky it a yellow colour, In the retort remained a light and very
* bulky coal.
Imparts neither fivp. LV. Ambergris {wims on water, and is not penes
tafte nor {mell : . : é 4
to cold water, a by it when cold.” It imparts to it neither taite nor
Mei,
Boiling | f
2
J
i
SP PA a AS at
a
it foluble foaps.
ANALYSIS OF AMBERGRIS. 183,
Boiling water is equally incapable of altering its properties. and to boiling
In this degree of heat the ambergris melts, aaa appears in the ieee
form of a isiokevifi oily fluid ; re a {mall quantity of black bitter tafte.
matter, infoluble in alcohol, feparates from it. The filtered
liquor has neither colour nor fmell, it has however a flightly
bitterith tafte.
It is only in confequence of the temperature therefore
that the ambergris melts, fince on this being lowered it re-
fumes the fame properties as before.
Exp. V. Acids in general have little ation upon amber-
gris. Thefe agents likewife do not enable us to difcover the
conftituent parts of this compound fubftance.
Dilute fulphuric acid effeQs no change in it, The con- S¥!phuric.
centrated acid expofes a little oxide of carbon.
The fame phenomena are produced by the muriatic an
oxigenated muriatic acid.
The nitric acid, at 18°, diftilled over this fubftance in the hee
pneumato-chemical apparatus, produces nitrous gas, carbonic bonicacid, and
acid, and azote gas, A ae
The azote gas arifes no doubt from the decompofition of
fome animal matters, accidentally mixed with the ambergris,
as may be obferved in the examination of {ome pieces.
After the extraGtion of the elaftic fluids, a thick liquor, in- and leaves a fub-
ftance analogous
Acids act but
feebly on it.
d Muriatic.
_ clining to a yellow colour, was found in the retort: this, OM to refins,
bringing it to a foft confiftency, flightly {welled up; and
being evaporated to drynefs, in a porcelain capfule, what
‘remained was a dry, bitier fubftance, of a golden yellow hue,
fining and tranfparent, and exhibiting properties analogous
to thofe of refins.
- Exp. V1. Alcalis combine with ainbergris, and form with Alcalis form
foap with ambere
; : : gris.
’ Into-a crucible of platina were put one gramme, 592 (30
_ fr. grs.)of ambergris, with 531 thoufandth of a gramme (10grs.)
_ of pure potath ; it was gently heated; the mixture melted,
4 without exhibiting any figus of the prefence of ammonia ;
on cooling a homogeneal brownifh mafs was obtained.
On this were poured 30 grammes (one fr, ounce) of diftilled
: water, which diffolved part of it, The folution was very
_alcaline.
The undiffolved portion remained in a foft tenacious mafs,
by which adhered to the fingers when warm.
2 : A large
a
184 ANALYSIS OF AMBERGRIS.
A larger quantity of water was added, and the whole was
diffolved.
Cauftic potahh Cauftic potafh triturated for fome time in a mortar with
does not facili- ‘ hive P Sere
tate its {olution 2™Mbergris does not facilitate its folution in water.
in cold water. Ammoniac does not aét on ambergris cold, but when heated
- aaatig diffolves it; the mixture gradually becomes brown, and on
the aidof heat. evaporation yields a glutinous faponaceous fubflance, in all re-
fpects fimilar to that obtained by means of potafh.
Itis folublein Exp. VII.° The fixed oils, as thofe of rape, olive, &e.
the fixed oils, diffolve amber with the affiftance of heat in a very fhort time ;
the folution is yellow and tranfparent, and becomes brown on
being evaporated.
galas the volas Exp. VIII. ' Volatile oils likewife diffolve ambergris.
; ‘ Thofe of turpentine, favine, and hyffop, exhibit the fame
appearances. The folution affifted by heat takes place pretty
readily.
On evaporating On evaporation a thick red magma is produced, incapable
folution a 6f complete deficcation, burning on the coals, and emitting a
magma is 5
left, whichis denfe fmoak, of a fmell refembling that of the ambergris.
Sati in al- Alcohol diffolved this fubftance, and thence acquired a golden
; yellow colour, but it was precipitated from it by means of
water.
Old volatile oils If volatile oils be too old, they will not completely diffolve
Aa no. diffolve i+ even with the help of long continued heat.
Soluble inether, Exp. 1X. It diffolves very quickly in ether, even cold.
ace ea Exp. X. The folution of ambergris by alcohol is the only
flituen: parts, “one that is really capable of affording us any certain refults.
Its conftituent parts may be feparated by it in fuch a manner,
that on reuniting them a compound is obtained, the qualities
of which came very near thofe of the original fubftance.
Part diffolved in 3.821 grammes (one drachm) of ambergris were reduced to
he without powder, put into a phial, and 61.143 grammes, (two ounces)
2
twenty four hours was fufficient to give the alcohol a deep
yellow colour ; it was filtered, and a frefh quantity of alcohol
another part by was poured’on the undiffolved portion. The folution was
means of heat; facilitated by increafing the temperature. The whole of the
Jeaving a little 3 : es :
black matter; ambergris being diffolved, except a fmall quantity of black
and feparating matter, the liquor was filtered while hot. It paffed through
when cold, the filter clear; but on cooling there feparated from it a light
pale yellow fubflance, part of which adhered to the fides of
the veffel,
The
: of reétified alcohol were poured on them. A maceration of,
\
ANALYSIS OF AMBERGRIS. 185
The firft folution in alcohol made without heat} and that This folution
which was poured off from the precipitate, were mixed to- aay or
gether, and evaporated to the confiltence of an extraét: it
was then of a reddith yellow colour, adhered to the fingers,
had an agreeable {mell, and a pleafant tafte. The evapora- le/t a refinous
: d : : ake ubftance.
tion being continued to drynefs, it appeared fhining and tranf-
parent, grew foft between the fingers, and burnt in the fame
manner as refins.
The experiment was repeated, to determine the characters
of thefe two fubflances more pofitively.
For this purpofe ambergris was left to macerate in alcohol phe experiment
twenty-four hours as before ; it was then filtered, and a frefh repeated.
quantity of alcohol was added to the refiduum, which was
macerated in the fame manner. The fecond liquor was lefs
coloured than the firft, A third portion of alcohol being poured
on what was left undiffolved ; its colour was fcarcely altered.
The flight a€tion of the alcohol on this refiduum feemed to
indicate, that it was no farther foluble in this menftrum ; but
I quickly found the contrary. I heated the mixture, and the
whole was inftantly diffolved, leavmg about 212 thoufandths
of a gramme, (four grains) only of a black powder, which The plack
was nothing but oxide of carbone. The {olution was filtered powder oxide
hot, and on cooling a whitifh yellow glutinous fubftance was of Sanaa
depofited, which was feparated from the tin¢ture.
This experiment fhows us the poffibility of feparating és Thue these
means of alcohol three very diftin@ fubftances ; the firft foluble ¢'ferent tub-
jagices fepa-
init cold; the fecond, by means of heat; and the third in- pateg,
foluble, which remains in the form of powder.
To determine the charaéters of the firft two fubftances, the whe Gch eve
tin@lure made without heat was firft evaporated to drynefs; amined.
when there remained in the capfule 1.167 grammes (22 grains)
of a brown fubftance, dry and fhining in its fraéture, unaltera-
ble in the air, and growing foft witha gentle heat ; 15° were
fufficient io give it a tenacious and glutinous confiltence ; and
being put on red-hot coals it was completely volatilized.. If
this experiment be made in a filver {poon, the volatilization
takes place with the fame rapidity, an odoriferous {mell is
diffufed around, and no coally refiduam is left.
Sufpeéting this fubftance might be in fome refpeé analogous pers from the
to the refin obtained from propolis by Cit. Vauquelin, I in- refio obtained
ftituted a comparifon between them, and found the following from propolis
_ differences ;
ift,
186 ANALYSIS OF AMBERGRiS,
in three ree Ift. It melts much ‘more flowly ; Qdly, it diffufes a denfe
a nai odoriferous vapour, refembling a little the fmell of honey 5 —
3dly, it {wells up, and leaves a very bulky coal.
Finally, this firft fubfance obtained from ambergris, which
may be confidered as a true refin, -is foluble in alcohol, and is
precipitated by water. The folution reddens litmus papery
7 which proves too, that the alcohol. diffulves the benzoic acid
previoufly dete@ted, either hy burning the ambergris under’a
bell, or by treating it with lime.
Examination of _ Nothing now remains, but to examine (he produét obtained
the fecond fub- 5 ; ; ; :
Rance. © Dy heated alcohol, after the refin is extraéted by maceration.
I have faid above, that there feparated from the alcohol by
refrigeration a fubftance, part of which fubfided to the bottom
of the veffel, and part adhered to the fides.
Being feparated from the liquor, and properly dried, it
remains a littie bulky and light. Under the preffure of the
finger it contraéts and crumbles, but it 1s foon lengthened out
and foftened by the heat. It has a laminated texture, if it be-
fuffered to cool flowly,
Js a true refin,
It retains between its particles a little water.and alcohol,
which may be feparated by keeping it a fhort time in fufion,
When melted over again it is much whiter than before, and
Its properties no longer exhibits its former granulated texture. In fine,
the fame with bh { pd | - - EM . . | : , b
Bhoke of the ave difcerned in it all the properties of the adipocerons fub-
adipocerous fub-fiance, difcovered by Cit. Fourcroy in the fatty matter of
detec dead bodies, and the properties of which he has deferibed in a
of dead bodies. paper publifhed in the 8th volume of the Annals of Chemifiry.
From 3.821 grammes, (72 grains) of ambergris, 2.016
grammes, (38 grains) of adipocerous maiter may be obtained.
/
Recapitulation.
From thefe experiments it appears we may conclude:
Recapitulation, 1 ft, That ambergris isa compound fubftance, which burns,
and may be entirely volatilized.
2dly, that on diftilling it alone we obtain from it a flightly
acid liquor, and an oil partly folubie in alcohol, and of an
empyreumatic {mell, —
3dly. That by fublimation, or by the procefs of Scheele, —
benzoic acid may be extraéted from it.
4thly, That water does not aét upon it.
5thly, bi
| - - STONES FALLEN ON THE EARTH. 187
'. Sthly. That by means of nitric acid a mattér analogous to
refins, mixed with the adip6cerous fubftance, is extrac¢ted
from it.
6thly. That the concentrated fulphuric, muriatic, and
oxigenated muriatic acid, convert it to a coal, without dif-
folving it.
7thly. That with alcalis it forms a faponaceous compound.
8thly. That fixed oils, volatile oils, ether and alcohol, are
the true folvents of ambergris.
: 9thly. And lafily, that alechol affords the means of feparat-
ing its conftituent parts in the following proportions,
_ Adipocerous matter | - - - - 2.016 grammes. Its conftituent
® Refin - 4 “ ~ = £ - 1.167 Eattss
_ Benzoic acid - ms - - - 0.425
i Coally matter Bit leap ket a) te UBUD
q i 3.820.
;
;
; LV.
An, Account of fome Stones faid to have fallen on the Earth in
France ; and of a Lump of native Iron, faid to have fallen in
India. By the Right Hon, Cuarres Grevite, F. R. §*, a
| | Tue experiments and obfervations made by Edward How- That ftony and
ard, Efg. on certain ftony and metalline fubftances faid to M*tallic bodies
a, have fallen on
have fallen on the earth, and the accurate defcription which the earth is
the Count de Bournon has given of thofe fubftances, have, fly *fablithed.
_ in my opinion, fully eftablifhed the following faét, namely, .
- that a number of ftones afferted to have fallen under fimilar
_ circumftances, have precifely the fame characters.
The ftones from Benares, that from Yorkfhire, that from
_ then been feenin England, They ail contained pyrites of a pe-
_ culiarcharaéter’: they all hadacoating ofblack oxide of iron: they
_ all contained an alloy of iron and nickel ; and the earths which
_ ferved to them as a fort of conne@ting medium, correfponded
_ in their nature, and nearly in their proportions.
i Since the publication of Mr. Howard’s and Count de Three new fpe~
~Bournon’ s obfervations, I have received from France three oe from
ranc€e~
* From the Philof. Tranf. 1803,
additional
i
188
Remarkable additional fpecimens. Monfieur St. Amand very obligingly
biftory. divided with me'a fpecimen he had broken from a ftone of about
15 inches diameter, preferved in the Mufeum of Bourdeaux,
which ftone fell near Roqueford, in the Landes, on the 20th
Auguft, 1789, during the explofion of a meteor; it broke
through the roof of a cottage, and killed a herdfman and fome
cattle. M. St. Amand alfo gave me part of a ftone he had
preferved in his colleétion ever fince the year 1790, whena
fhower of ftones, weighing from 4 an ounce to 15 and 25
pounds each, fell in the parifhes of Grange and Creon, and
alfo in the parifh of Juliac, in Armagnac; which faét was, at
the time, verified by Duby, Mayor of Armile, and publithed
by Bertholon, in the Journal des Sciences utiles de Montpellier,
in the year 1790.
a The third fpecimen, I owe tothe Marquis de Dree ; it is a
fragment, broken from a ftone of 22 pounds weight, which
fell near the village of Salles, not far from Villefranche in
Burgundy, on the 12th of March, 1798; this was alfo ac-
companied by a meteor.
Thefe three I content myfelf with the mere recital of the faéts, mm con«
= aan firmation of the obfervations prefented to the Society, as thefe
the others, three additional fpecimens have precifely the fame characters,
texture, and appearance, as the others in my colleétion; and
are {carcely, by the eye, to be diftinguifhed from them.
I fhould not, perhaps, have troubled the Society with this
account, as my friend the Marquis de Dree, whofe knowledge
in mineralogy peculiarly qualifies him to inveftigate thefe fub-
jects, has given me hopes of feeing his obfervations on them
publifhed ; but a new evidence has lately fallen into my hands,
and is the only one I have met with that afcertains the origin
of native iron, which from analyfis, had been fufpected to have
Metallic ftone @ Conamon origin with the {tones fallen on the earth. Con-
that tell in India yerfing with Colonel Kirkpatrick, whofe refearches have
rir a, “™" embraced both the literature and politics of India, and whofe
talents had placed him in very important filuations in various
parts of India, I inquired whether he had ever heard of any
inftances fimilar to the explofion of the meteor at Benares in
1798. He told me, he could not recolleét having heard or’
read of any other inftance, excepting one in the Memoirs
written by the Emperor Jehangire, and of that he did not
recolleét the particulars. A few days after, having found the
paflage
STONES FALLEN ON THE EARTH.
/
STONES FALLEN ON THE EARTH. 189
paffage i in the origival Perfian, he was fo obliging as to tranflate
- it. Iconfider it as an authentic fa@; for the Emperor Jehan-
gire was nota prince on whom his courtiers would idly venture
to impofe; and there can be-little probability that an Aumil
of a diftrict fhould invent fuch a ftory, or be able to produce
a fubftance apparently like iron, but which, on trial, differed
from manufaétured iron. Colonel Kirkpatrick’s tranflation I
have obtained his leave to communicate, with his atteftation,
to the Royal Society.
Extra& from the Memoirs of the Emperor Jehangire, writien (in
Perfian) by himfelf, and tranflated by Colonel Kirkpatrick.
A. H. 1030, or 16th year of the reign.—The following is Narrative
among the extraordinary occurrences of this period. eas oe
Early on the 30th of Furverdeen, of the prefent year *, and gire of a metallic
in the Eaftern quarter, fof the heavens] there.arofe in one of ripeness a
the villages of the Purgunnah of Jalindher +, fuch a great and : i
tremendous noife as had nearly, by its dreadful nature, dauvinel
the inhabitants of the place of their fenfes. During this noife,
a luminous body [was obferved} to fall from above on the
earth, fuggefting to the beholders the idea that the firmament
“was raining fire. Ina fhort time, the noife having fubfided,
and the inhabitants having recovered from their alarm, a
courier was difpatched [by them] to Mahommed Syeed, the
Aumil ¢ of the aforefaid Purgunnah, to advertife him of this
event. The Aumil, inftantly mounting, [his horfe,] proceed.
ed to the fpot, [where the luminous body had fallen]. Here
he perceived the earth, to the extent of ten or twelve guz §,
in length and breadth, to be burnt to fuch a degree, that not
_ the leat trace of verdure, or a blade of grafs remained ; nor
had the heat [which had been communicated to it] yet fub-
fided entirely.
_ ™® The firft of Furverdeen of this year, (A. H. 1030,) cor-
_ refponded with Saturday, the 27th of Rubbi ul Akhir; con-
fequently, the 30th of Furverdeen fell on the 26th of Jummad ul
_ Ouwul, or A. D. 1620.
_ A purgunnah is a territorial divifion, of arbitrary extent.
_ The purgunnah of ‘falindber is fituated in the Punjaub, and about
100 miles S. E. of Lahore.
+ Aumil is a manager or fiscal fuperintendant of a diftri&.
A, guz is rather lefs than a yard.
S48 i Mahommed
190 STONES FALLEN ON THE EARTH.
Mahommed Syeed hereupon directed the aforefaid {pace of
ground to be dug up; when, the deeper it was dug the
greater was the heat of it found tobe. At length, a lump of
iron made its appearance, the heat of which was fo violent,
that one might have fuppofed it to have been taken from a
furnace. After fome time it became cold; when the Aumil
conveyed it to his own habitation, from whence he atfter-
wards difpatched it, in a fealed bag, to court.
It weighed up- Here I had [this fubftance] weighed in my prefence. Its
ied hah weight was one hundred and fixty tolahs.* I committed it:
brittle. to a ikilful artifan, with orders to make of it a fabre, a knife,
andadagger. The workman [foon] reported, that the fub-
ftance was not malleable, but fhivered into pieces under the
hammer.t
Upon this, I ordered it to be mixed with other iron. Con-
formably to my orders, three parts of the iron of lightmings.
were mixed with one part of common iron; and from the
mixture were made two fabres, one knife, and one dagger.
With the addi- By the addition of the common iron, the [new] fubftance
ai ei acquired a [fine] temper; the blade [fabricated from it}
of common iron
to three parts of proving as elaftic as the moft genuine blades of Ulmanny,§
Ake ah and of the South, and bending, like them, without leaving
5) 3 js > ;
blades were any mark of the bend. I had them tried-in my prefence,
a ee and found them cut excellently; as well [indeed] as the
belt genuine fabres. One of thefe fabres I named Kataz, or
the cutter; and the other Burk-ferifht, or the lightning-na-
tured.
A poet|| compofed and prefented to me, on this occafion,
the following tetraftich.
~ « This earth has attained order and regularity through the.
‘« [Emperor Jehangire :
‘<< Inhis time fell raw iron from lightning :
«« That iron was, by his world-fubduing authority.
«« Converted into a dagger, a knife, and two fabres.”
* A tolah is about 180 grains, Troy weight. t
+ Literally, ‘¢ it did not ftand beneath the hammer, but fell to - i
pieces. . i
{ This expreffion is equivalent to our term thunder-bolt.
§ The name of the place here defigned is doubtful. 7
|| The poet is named in the original ;. but the name is not per> |
fectly legible. om |
AWALYSIS OF THE NATROLITE. 191
The chronogram. of this occurrence is contained in the
‘words* ( . - ) which fignify ‘ the flame of the
imperial lightning ;” and give the year (of the Hegera) 1030.
N. B. The foregoing tranflation (which is nearly literal}
has been made from a manufcript that has been feveral years
in my poffeflion; and which, although without date, bears
marks of having been written at a remote period.
WM. KIRKPATRICK.
\
V.
Analyfis of the Nairolite. By Kuarrotu.t
x
‘ 4 Fa >
q ‘| HE foffil which forms the fubjeé& of this analyfis, and to Natrolite found
” fpecific gravity.
Bes
) fome time ina 4lver crucible, loft nine grains. The figure
. into a tranfpare snt clafs, full of {mall air bubbles.
heat of a porcelain furnace, fufed into a tranfparent glafs of a
light brown colour.
q2t mn in
which I give the name of natrolite, for reafons to be ftate Se he
hereafter, is found at Hégau in Suabia, on the borders of
Switzerland, It is depofited in the crevices, or clefts and ca-
vities of the fonorous porphyry. (Klinginftein Porphyr) from
having a found, nearly metallic, which form the mountains
and rocks of Hohentwie!, Hohenkrahen, and Magdeberg.
The colour of this foffi! is a dirty ochreaceous yellow, ap-Itscoloura dirty
proaching fometimes to an Ifabella yellow, at other times to Yellow.
a yeliowifh brown, interfeéted with concentric white lines,
It is compaét, its internal fracture hasa filky luftre. It breaks Its properties
"into wedge-like pieces, the edges of which poffefs little tran-
parency ; if is not very hard, extremely brittle, and of=2,200
A
a. 100 grains of natrolite, after having been ignited for Ignited ina
ss filver crucible,
of the ftone was retained, but its compaétnefs was con-
) fiderably diminifbed.
b. the blow-pipe on charcoal, natrolite fufes quickly Fufes quickly
Before the blow-pip q ¥ Before the blow-
PIR :
c. Natrolite placed in aclay crucible, and expofed to the Ina porcelain
furnace melts
into a brown
glafs,
\
_* The Perfian “charaéters are given in the Tranfactions. N.
+ Abftra& of an Effay in the memoirs of the Royal Academy
of Sciences at Berlin, 1803, page 243.
; d. In
2 ANALYSIS OF THE NATROLITEs
with minute d. In a charcoal crucible the mineral afforded the fame
globules of iron
in the furface, Produét. The glafs pearl exhibited on its furface.minute glo-
bules of iron, ;
B.
'Diffolved in a. 100 grains of finely levigated natrolite, were mixed into
Batre abides 7 pafty fluid with water, put into a flafk, and digefted in mo-
derately ftrong muriatic acid. The folution was foon effeéted,
and it exhibited a reddifi yellow gelatinous mafs. After di-
The filiceous —_Jyting it copioufly with water, and continuing the digeftion,
earth being pre- : ‘ é d
cipitated by the filiceous earth feparated, which, being colleéted an
watery dried, weighed 48 grains.
cubic cryftals b. The fluid altatnedl in the laft procefs on evaporation,
were obtained.
yielded cubic cryftals, The remaining fluid being further
The dry mafs evaporated to drynefs, the dry mafs was pulverifed, and di-
digefted in ale gefted with a gentle heat in alcohol. Having fuffered the al-
i coholic folution to cool, a white faline powder was depofited ;
the alcohol was therefore decanted, and the powder colle&ed,
wafhed in fpirit, and dried. The remaining alcoholic folution
was afrefh evaporated, a fmali quantity of the fame faline
powder became feparated, which was added to that obtained
before.
The refiduum c. The refidue of the procefs b infoluble in alcohol, was
age in Was" diffolved in water, On adding to this folution liquid ammonia, ~
precipitated by alight flocculent precipitate became depofited. This being
miineiei feparated by the filtre, the fluid which paffed through, was
evaporated by a gentle heat. The falt obtained, weighed when
perfeétly dry, 313 grains.
The folution in . The alcoholic folution 6 (which from other experiments, —
alcohol decom- was known already to contain nothing but alumine and oxide |
pofed by am- ; ; : :
saghia of iron) after being diluted with water, was decompofed by
liquid ammonia, and the precipitate colle€ted and dried.
The fluid, from which this precipitate had been feparated,
was evaporated, and the mafs ftrongly heated, fo as to vola- —
tilize the muriate of ammonia that had been formed, when
there remained two grains of falt, which being diffolved in |
water, yielded cubical cryftals.
Tbe precipitates ¢, The precipitate obtained by means of liquid ammonia d,
ae car together with that before produced c, were put into a folu-
tion of pot-ath, and digefted with that fluid. A folution was_
effeGted, and oxide of iron feparated, wohiaey after being igs
nited, weighed 13 grains.
f, The |
ANALYSIS OF THE NATRGLITE. 1938
Ff. The alcaline folution e was mingled with muriatic acid, Alumine fepa-
till the precipitate produced, became rediffolved, and was then prio aitens stale
decompofed by carbonate of foda. The precipitate obtained
after being wathed, dried, and ignited, weighed 242 grains,
It was alumine.
g. It remained ftill to examine the alcaline part of the foffil, The alcaline
which produced with muriatic acid the 312 gr. c. and the —
two grains d. Tafte, figure of cryftals, and chemical re-
agents, proved it to be muriate of foda. A folution of it in
water, mingled with a concentrated folution of tartareous
acid, did not produce tartarite of potafh. Another part of
the folution, after being decompofed by fulphuric acid, yielded
fulphate of foda,
Having afcertained by experiments that 100 parts of abfo«
lutely pure carbonate of foda *, dried in a heat of ignition,
when faturated with muriatic acid, loft 41 parts by weight of
carbonic acid, and yielded 1204 parts of dry muriate of
foda (the deficcation of which was not continued te decre-
pitation) we may conclude, that the above 332 grains of mu-
riate of foda contained 164 of foda.
100 parts of the natrolite confequently yielded : Component
‘. parts of natres
Siliceous earth B. a ~ - +48. grs. lites
Alumine - AFA fait, ws: ante LASS
Oxide ofiron - e - ae ao:
Soda~ + - g Die, 2 16550
Water .- A.’ a - -
99.50
The {mall number of foffils which contain foda, is therefore
‘augmented by one more. That foda was contained in this
ftone might perhaps have been expeéted, on account of its
forming frequently the matrix of the fonorous porphyry, which,
__* In order to obtain perfeély pure carbonate of foda, I diffolve Pure carbonate
_ common carbonate of foda in water, and faturate this folution ° 14%
with nitric acid, taking care that the acid is a little in excefs. I :
_ then feparate the fulphuric acid by nitrate of barytes, and the .
muriatic acid by nitrate of filver. The fluid thus purified I eva-
porate to drynefs, and fufe the nitrate of foda obtained, and decom-
pofe it by detonation with charcoal. I then elixiviate the refidue,
filter, and cryftalize the carbonate of foda.
Vor. VI.—Novemser, 1803, O it
194 AEROSTATIC MACHINES.
it is now known, always contains this alcali, but as the quan-
tity of foda contained in this foffil, is twice as large as that
which exifts in the fonorous porphyry, I have not hefitated at
giving it the name of natrolite.
Vi.
On the Employment of Aerofiatic Machines in the Military Science,
and for the Conftruétion of Geographical Plans.* By Citizen
A. F. Lomer.t
Prefent ftate of Tue acroftatic art is ftill in its infancy; and whatever pre-
aeroftation, grefs may have been already, made in it, it is impoffible to
forefee all the refources it may afford, or to determine the li-
mits of its utility. Time and experience muft fix our opinions
refpe€ting it; but it is of confequence to obtain the affiftance
Its improvement of learned men and artifts in this interefting purfuit; and as the
ma Ke ay {malleft inveftigations of this nature are generally too expen-
werimnent. five for individuals, it is neceffary that the government fhould
fupport an eftablifhment particularly devoted to the praétice
and improvement of the proceffes which conftitute it.
Advantages to Aeroftats will furnifh, in prefence of an enemy, one or
be derived from more points of obfervation at pleafure, from which the pofi-
its ufe in war. |. : ; , .
tions he occupies may be reconnoitred, his movements ftudied,
and his maneuvres judged of in the grofs, or appreciated in
the moft minute detail. It may be prefumed that thefe ma-
chines will become of the moft indifpenfable utility in war, be-
caufe they fupply it with an extraordinary means, hitherto un-
known, of making obfervations, which may in an inftant de-
termine the fate of battles, fecure the difpofitions for a vigoroug
defence, or at leaft point out the moment and the moft con-
venient outlets for a retreat; and more particularly to draw at--
tention to the advantages which an army may derive from bal-
Taftances loons, it will be fufficient to remember the happy ufe made of
them at the battle of Fleurus. -
* Adjutant-commandant, formerly keeper of the colleétion of
models belonging to the Polytechnic School, and now at'the head of
the fixth divifion of the war department. (Military operations and:
movement of the troops.)
t+ From Journal de l’Ecole Polytechnique, Tome 1V. p. 252.
| The.
“A®RostAtie MACHINES; 195
The Committee of Public Safety, and afterwards the Exe- Experiments
-Cutive Directory, thought that the application of aeroftats to apa
_ inilitary inquiries of every defcription ought to be ftudied and the French
practifed during peace. They were alfo defirous, that they sovernments
might be employed in the conftruétion of geographical plans,
or at leaft in afcertaining the intermediate particulars of the
territory between the points which had been geometrically de-
termined. Having been charged with the experiments re-
lative to thefe different applications, I purpofe giving an ac-
count of the principal refults.
The intention, from the firft afcents, was to meafure the Firft attempts at
angle formed by the vifual rays falling on the eye of the aerial ane hae
obferver, from feveral determinate points on the earth: The fual rayse
unavoidable motion of the aeroftat preventing the ufe of the
graphometer in this operation, a recipiangle was at firft fub-
ftituted, fufpended like a mariner’s compafs, by the affiftance
of which, it was hoped the meafure of the angles would be
eafily taken, and particularly that they would be obtained with
immediate relation toa horizontal plane. This attempt not
having fucceeded, it was neceffary in future to make ufe of a
fextant.
This inffrument was every thing that could be defired for The ufe of the
celerity, as well as for the facility aa precifion of the obfer- ee ea
vations, but it has this inconvenience, in the cafe in hand, that
it only fhews the angle ona plane inclined to the horizon; and
moreover, in its ordinary confiruétion it furnifhes no means of
noticing this inclination. The perpetual agitation of the ma«
chine is another fource of error; in fa@, an aeroftat, kept eles
vated and held by cords, is continually changing pofition; it.
_ moves in fpace, defcribing alternate ellipfes, the curvature of
which is modified to infinity, according to the violence of the
wind, the elafticity of the cords, and the fituation of the places
to which it isfaftened. It leaves then no trace of its variations,
and does not permit the obferver which it fupports, to add to
the meafure of any angle whatfoever, that of the two angles
neceffary to conneét the firft with the plane of the horizon.
_ Neverthelefs, for plans relative to the generality of military But is nevers
inquiries, and in all cafes where a ketch of the figure of the aeee A gg
earth is fufficient without attending to flight inaccuracies in cafes,
diftances, fimple obfervations, made with the fextant, will
anfwer the purpofe, and furnifh the means of operating with
O2 facility
196 AEROSTATIC MACHINES.
facility over a vaft extent of territory, fecure from the attempts.
of anenemy. But it is not equally ferviceable in operations
which require a rigorous exaétnefs, and in which it is requi-
fite to conneét the angles with the centre of the ftation, and
with the plan of the horizon.
Additional ap- The following is the mode in which I have endeavoured to
en Pap fulfil the various objeéts :
capable of indiz The angles neceflary for conneéting the pofition of two ob-
cating a// the re- jets with the centre of the ftation and the plane of the hori-
quired angles.
zon, are, lft. the angle comprehended between the rays fall-
ing on the eye of the obferver from thefe points; 2d. the an-
gles formed by each of thefe rays with the perpendicular.—
We have feen, that it is impoflible for the aeroftatic obferver
to mark thefe three angles by taking them after each other;
but if their meafure were inflantaneous, the difficulty would
be overcome. This would therefore be the cafe if an inftru-.
ment could be devifed, which would give thefe three angles
_at once bya fingle obfervation; and as the fextant already
fhows the angle ‘oummatchendad between the rays, the objeét
in view is to add the neceffary parts to that inftrument for ob-
‘taining the other two at the fame time.
Preliminary ob- Let BAC (Plate X.) be the angle formed by the vifual rays
fervations. AB, AC;; falling on the mirror A of the fextant from the ob- ©
jeGts B and C; if the index A Dbe moved until the image
of the obje€&t C reflected by the mirror A placed on the index
coincides by double refleétion on the mirror L, with the point
where the obje& B is feen; and if they be both perceived at
the fame time by the obferver looking through the telefcope P,
itis known, (by the Theory and Ufe of the Sextant) it, That the
angle D AE, comprifed between the index A D and the fixed
radius or line of zero AE of the inftrument, is always equal
half the angle BAC, the meafure of which is required:
2d, That the line R B, which is fuppofed to pafs through the
axis of the telefcope and the centre of the mirror L, is always
direGted to the point B, and is ufually taken for the fide A B;
the error arifing from the {mall diftance A R being confidered
as nothing in praétice: hence, if we fuppofe a vifual ray pafl-
ing from the point R to the objeé&t C, the angles BRC and
B AC may be reputed equal, and be taken indifcriminately
for each other.
This
AEROSTATIC MACHINES. JOT
This being premifed, if a ruler be placed in the dire€tion Method of af-
RB, it may be confidered as in that of the fide AB, and eee eur ae
if we can fucceed in fixing a fecond ruler in fuch a manner vifual rays.”
that the moveable index fhall carry it into the dire@tion R C,
at the infant that the images of the two objets B and C
are brought into one at the point L, it is evident that thefe two
rulers will form between them the angle BRC, and confe-
quently the angle BAC.
Toaccomplifh this, let us fuppofe a fort of falfe {quare, SR Q,
fituate in the plane of the inftrument, and moveable at its axis
on a pivot fixed at the point R, at the interfeétion of the lines
ARand RL; making the angle SR Q, comprifed between
its arms, equal to the anyle ER L, and the fide R S equal to
the diftance AR. If now we fuppofe that the extremity S of
the fide R S, is retained by a button ina groove M N, worked
in the moveable index, the movement of it will be communicated
to the falfe fquare in fuch a manner that the angle LR Q will
always be equal to the angle B A C, and confequently the fide.
R Q will be placed in the requifite direétion.
In faét, the triangle ARS being ifofceles in its form, the
exterior angle SRE=RAS+AER.= 2RAS=BAC;
but SR Q being equal toE RL, if the common angle SRL
be taken away, there will remain the angle S RE=LRQ=
BAC.
Now let us fix under each of the two rulers R L and Q R Obfervation of-
a {mall graduated quadrant, fufpended in fuch a manner bbe ae
that it will place itfelf in the vertical plane of the fide corref- yifual rays and
ponding to the angle obferved; let us affix to each of thefe te perpen-
quadrants a plummet, compofed of a ftiff arm moveable upon oe
a pivot, and furnifhed with a nonius index and a weight, which
gives it a conftant tendency to affume a vertical pofition, in
whatfoever fituation the fextant may be placed; finally, let
the whole be fo difpofed that the index of each plummet may
be retained at will, at the divifion indicated on the limb by the
effe&t of the fufpenfion, and this by means of a trigger, which
can be pulled at the exaét inftant of obferving the principal ;
angle in the points of reflexicn. It is evident that the fimul- shee cr ss
taneous aétion of the two rulers and the plummets will fhow plane on the
the three angles fought, and that nothing remains but to re- horizon are
: btained b
duce, by calculation, the angle B AC to the plane of the ho- calculation.
rizon.
This
198.
Succefs of the
inftrumente
Probable future
advantages.
Method of con-
neCting all the
obferved angles
in one com-
mon centre.
Application of
the procefs.
Inaccuracy to be
expected from
an inexperiened
obferver,
AEROSTATIC MACHINES.
This inftrument, arranged in the manner here defcribed,
produced every defired effeGt in our experiments. The irs
vention, as fimple as it is happy, may become very important
from the ufeful applications of which it is fufceptible; and there
is already reafon to hope that, by bringing this to perfeétion,
or bythe formation of fome analogous inftrument hereafter,
there will be a poffibility of executing trigonometric operations-
with much correétnefs, by the afliftance of aeroftatic machines, °
notwithftanding their continual motion,
It was not enough to have difcovered the means of conneét=
ing the angles with the plane of the horizon: it was ftill de-
firable, that all the angles obferved during afcents in any one
place, fhould have a relation to the common centre of obfer-
vation. To accomplith this, it was neceffary to keep a regifter,
by fome means, of the fituation of the machine at the precife
moment of meafuring each of thefe angles. This was done by
dropping from the aeroftat, at that inflant, a {mall flake, leaded
and furnifhed with an iron point. This ftake fell rapidly to the
earth, into which it ftuck, and marked a point correfponding
to the fummit of the angle meafured. It was then eafy to
compare the pofition of’this point, with that of one taken for
the common centre of the obfervation, and thence to deduce
the neceflary correétions, It muft however be noticed, that
the ftake, when abandoned to itfelf, acquires, at the inftant of
its fall, a compound motion which partakes of that of the
aeroftat, and confequently is not exactly vertical; but the er-
ror which refults from this deviation is but flightly perceptible
in practice.
The calculations and ordinary proceffes of defcriptive ge-
ometry will furnifh all the means of making ule of thefe differ-
ent obfervations, and of expreffing the refults on paper; not
only for their application to the conftru@ion of maps, but alfo
to afcertain heights compared with the level: but we {hall
not in this place enter into any details on that head.
The obferver engaged making thefe firft experiments,
foon perceives that the involuntary embarraffment, occafioned
by the novelty of his fituation, when he finds himfelf infulated
and fufpended at a height of feven or eight hundred metres,
has’ a confiderable influence both on the fidelity of his ob-
fervations and. on the time neceffary for making them. All
certainty depends, in faét, upon the confidence and readinefs
of
AEROSTATIC MACHINES. 199
ef the obferver; and it cannot be concealed, that it may
produce great inconveniences, becaufe this difficulty of ope-
rating opens wide limits for the errors which it is poffible to
commit. |
From this laft obfervation it will be feen: 1ft. That it is in- Conditions nee
di{penfably neceffary to have acquireda great aptitude for thefe eefiary oe
correét obfer-
fort of obfervations, to be able to execute them with precifion : vations.
2d. That the proceffes juft defcribed are more fatisfaétory in
theory than they would be in thofe applications which require
ftrict accuracy; and, that though there are fituations in
which nothing can be fubftituted for their ufe in the conftruc-
tion of fome figured plans, it is at leaft proper never to ufe
them in preference to thofe means of obfervation which are
better known, and which can be employed with more cer-
dainty.
But it cannot be too often repeated, at the fame time, that Advantages to
aeroftats furnifh the means of giving the moft lively intereft to ana aetie te
the delineation of the figure of the earth, in maps of all de- joons in furvey-
fcriptions; and that their ufe is of the greateft afliftance in the img countries.
formation of plans, the outline of which may be fufficiently
defined by a fimple eye-fketch. The aerial obferver, by
difcovering a vaft extent of country, accuftoms himfelf fully
to confider tle general organifation of the afperities of the
country, and even the particulars of its varieties, as well
as the tone of colour, which appear to give a different charac-
ter to each portion of territory. If this new method of obfer-
vation be cultivated with afliduity, it will doubtlefs lead to a
fenfible improvement in the art ‘of drawing plans. But to be-
nefit by the advantages which it affords, it 1s neceffary, that
thofe who are deftined to this employment fhould join a pro-
found knowledge of géometry to a great facility in defigning
landfcapes. May they be convinced of the importance of this
truth, and affure therafelves that no part of the plan can arrive
at perfe@tion, either ornamental or relative to civil and mili-
tary purpofes, unlefs ftri€t accuracy in the outline is accom-
panied by that fidelity of expreffion which is capable of pro-~
ducing in thofe who infpeét the plans, all the ideas which the
obferver had formed from the afpeé of the country.
_’ From all that has been faid, we may conclude, that the aero- valuable pro-
ftatic art combines properties no lefs valuable than unqueftionable At doe
in topographic operations and military refearches; that its per- Bie
fection
hines.
200
pia ufe of
eMe
Scheele dif-
covered an ine
fizmmable ar-
Seniated gas.
Its properties.
ARSENIATED HIDROGEN GAS.
feétion may produce new and invaluable properties; and. that
it would be equally impolitic to negleé the ufe of thefe ma-
chines, or not to obtain for them the information to be derived
from reflection and experience. We fhall terminate this me-
moir by an obfervation relative to their military ufes. Our
enemies would not fail to oppofe to the creative induftry of
of France, an induftry of imitation: they would alfo have their
balloons and ballooneers (ueroftiers.) The influence of this
innovation in war is of a nature to fpread with. rapidity, and
it muft foon ceafe to favour any nation exclufively. But even
in this cafe the art of aeroftatic machines will have acquired a
higher degree of intereft, becaufe another element fhall then
be in the power of man, in which the efforts of genius and .
induftry may be fubftituted inftead of the inconfiderate devafta-
tions of force; and this obfervation ought to intereft the friends
of hu-manity in bringing them to perfection.
Vi.
Chemical Analyfis and Properties of Arfeniated Hidrogen Gas
By Proressor TROMSDORFF.*
"THE immortal Scheele, in his effay on arfenic and arfenic
acid,t mentions an inflammable arfeniated gazeous fluid, of
which he fays: ‘¢ Hine intelligas, hunc aerem inflammabilem eff,
regulumque arfenict folutum tenere.” Scheele ftates, that he ob-
tained this gas during the folution of tin in arfenicacid. The
properties of this gas, as pointed out by him, are the follow-
ing. Arfeniated hidrogen gas is infoluble in water; it does not
render lime-water turbid; mingled with atmofpheric air, no
diminution of bulk enfues; on bringing the flame of a taper
in contaét with this mixture, a loud detonation follows, and
metallic arfenic is depofited. Interefting as the obfervations
here pointed out muft appear to every chemift, the obje& has
been negleéted by fucceeding operators.
* From a memoir, read in the Royal Academy of Sciences at
Berlin, 1803, p. 370.
+ C.H. Scheele Om Arfenick och defs Syra; Kongl. Svenkk.
Vetenfkaps Academiens Handlingar. Ar. 1775. V. xxxvi. 265.
Prouft
ARSENIATED HIDROGEN GAS. 201
Prouft is the only philofopher who mentions this gas: * he Prouft mentions
obtained it by digefting arfenious acid and zinc, in dilute ful- its
phuric acid ; on burning the gas, he obtained fometimes arfe-
nious, at.others arfenic acid. Being perfuaded that the for-
mation and properties of this gas deferved a clofer examination,
I inftituted a feries of experiments, the refults of which are as
follows.
Methods of obtaining urfeniated Hidrogen Gas.
1. There are a variety of proceffes for obtaining arfeniated Proceffes for ob. »
nidrogen. It is produced by heating tin filings in liquid arfe- ame
nic acid. This method is the moft expenfive and moft tedious. gas.
During the evolution of the gas in this procefs, arfenic, al-
loyed with tin, is precipitated, and the fluid obtained, holds in
folution, arfeniate of tin.
2. It is likewife formed by treating ina fimilar manner, arfe-
nic and iron with muriatic acid.
3. Arfeniated hidrogen is alfo produced by heating a mix-
ture of arfenious acid, iron filings and muriatic acid. The
fluid, in this cafe, contains muriate of iron and muriate of
arfenic.
4. Tin filings and arfenic acid yield this gas under fimilar
circumftances.
5. Four parts of granulated zinc and one of arfenic, treated :
in a fimilar manner with fulphuric acid, previoufly diluted with
two parts of water, afford arfeniated hidrogen very readily.
The gas obtained according to either ar thefe proceffes, is Beft produced
nearly alike, but that produced according to the laft procefs sree
feems to be the moft perfeét gas, for it contains no excefs of fulphuric acid.
hidrogen. When arfeniated hidrogen is produced by means
of zinc, arfenic, and dilute of fulphuric acid, the quantity
of arfeniated hidrogen is lefs than the quantity of hidrogen
which would be obtained in decompofing water in a fimilar
manner, without the interpofition of arfenic. The refidue,
after the evolution of the gas has ceafed, contains metallic arfe-
nic; part of the hidrogen muft therefore have aéted on the
oxigen of the arfenic acid, in order to reduce it to the metal-
- jie ftate. From what has been ftated, it appears that arfeni-
ated hidrogen contains arfenic in a metallic ftate, and not in
the ftate of arfenious, or arfenic acid. This will become more
_ obvious in the fequel of this paper.
: * Journ. de Phys, T. II. p. 173.
Phyfical
202
ARSENIATED HIDROGEN GAS.
Phyfical Properties of Arfeniated Hidrogen Gas.
Its phyfical proe Arfeniated hidrogen is a permanent elaftic aeriform invifible
pesties.
Its chemijcal
properties.
Mixed with nie
Prous £ase
With oxiginized
muriatic acid
gas.
fluid. It is a trae chemical compound. Prouft afferts that it
depofits arfenic: This however I have never been able to ob-
ferve, if the gas were pure. It has an alliaceous fetid fmell.
It extinguifhes burning bodies. It is not abforbable by water;
but when this fluid is freed from atmofpheric air, it takes up a
{mall quantity of the gas which becomes difengaged again by
mere agitation. It does not change the colour of tinéture of
litmus. The fpecific gravity of arfeniated hidrogen is, at 28°
barometrical preffure = 0,5293, or, one cubic inch fold French
meafure) weighs 0,2435 grains. It is therefore lighter than
oxigen, nitrogen, atmofpheric air, carbonic acid, nitrous gas,
ammonia, and gazeous oxide of carbon, but heavier than hi-
drogen and fulphurated hidrogen gafes. It is abfolutely fatal
to animal life,
Chemical Properties of Arfeniaied Hidrogen Gas,
Arfeniated hidrogen, mingled with atmofpheric air, fuffers
no chemical change, but meredilution. The fameholds good
with refpe@ to nitrogen. When mingled with nitrous gas, a
diminution of 0,02, or 0,03 takes place, which fometimes even
amounts to0,05. To afcertain the nature of this gas, I mixed
two parts of arfeniated hidrogen, with one of nitrous gas, and
gradually added oxigen, till no further diminution of bulk en-
fued. On prefenting to this mixture a lighted taper, a loud
explofion took place, accompanied with flame. Probably part.
of the oxigen added, remained uncombined; for a mixture of
two parts of nitrous gas, and three of arfeniated hidrogen,
could not be inflamed by the taper; arfeniated hidrogen is,
mifceable with hidrogen, with carbonic acid, and with ammo-
nia in all proportions.
Into acylinder half filled with arfenic and hidrogen, I fent
up bubbles of oxiginized muriatic acid gas. The bulk of the
gas was diminifhed, heat was evolved, and metallic arfenic
was depofited in a cryftalline ftate. On adding to the mixture
an additional dofe of oxiginized muriatic acid gas, white fumes
appeared, and the depofited metal vanifhed. The fame ex-
periment was repeated fucceflively, taking care toadd no more
of the latter gas, than was juft {ufficient to occafion the pre.
cipitation
&
ARSENIATED HIDROGEN GAS, 208
cipitation of metallic arfenic. The colleQ@ed metal yielded
nitrous gas, by the affufion of nitric acid, and on adding to
this mixture muriatic acid, arfenie acid was produced. The
arfenic depofited in the manner ftated before, when laid on
ignited coals, became volatitized in thick white fumes, yield-
ing arfenious acid. The precipitation of metallic arfenic muft
be afcribed to the decompofition of the oxiginized muriatic acid
gas; the oxigen of this gas uniling with part of the hidrogen
of the arfeniated hidrogen, and forming water, and thus fe-
parating the arfenic. For the arfenic is capable of being ox-
ided by the muriaticacid. Should it be imagined, that arfenic
exifted in arfeniated hidrogen, in the oxidized ftate, and that
it became precipitated by the oxiginized muriatic acid robbing
it of its oxigen, we fuppofe things analogically erroneous, for
the oxiginized muriatic acid is more capable of giving cut oxi-
gen than of taking it. The experiments of Chenevix feems
perhaps hoftile to this affertion; but the experiments of this
philofopher merely prove that the oxiginized muriatic acid is
capable of combining with an additional dofe of oxigen, and
conttituting with it a hyperoxiginized muriatic acid, This ~
certainly cannot be the cafe in the prefent inftance, as will
appear more evident from what I fhall {tate prefently.
J filled a cylinder in the mercurial pneumatic trough, with Further experi«
arfeniated hidrogen, and fent up into it as expeditioufly as pof- ents with this
fible, a quantity of oxiginized muriatic acid gas. The refult ela ict
was evolution of heat, diminution of volume, and the inner
_ fides of the cylinder became covered with a kind of dew. A
formation of water had therefore a¢tually taken place in this
experiment. Into another dry cylinder half filled over mer-
cury, with arfeniated hidrogen, I introduced dry muriatic
acid gas. In this cafe no diminution of bulk, no feparation
of arfenic enfued; no changeat all took place. Repeating the
fame experiment, I introduced into the cylinder a fmall quan-
tity of water; the muriaticacid gas was abforbed, and the re-
_ fidue was arfeniated hidrogen unaltered.
Into a cylinder half filled with oxiginized muriatic acid gas,
I paffed gradually arfeniated hidrogen in fmall bubbles at a
_ time; in this cafe no metallic arfenic was feparated, but thick
white clouds appeared. On continuing the addition of arfes
Miated hidrogen till no more white fumes appeared, metallic
arfenic was depofited, Jt follows from this experiment, that
when
904 ARSENIATED HIDROGEN GAS.
when a fall quantity of arfeniated hidrogen is made to act
upon a large quantity of oxiginized muriatic acid gas, part of
ihe oxigen of the oxiginized muriatic acid gas combines, not
only with the hidrogen of the arfeniated gas, and forms water,
but the metallic arfenic alfo becomes oxidifed. Reafoning from
this faét, we fhould be inclined to believe, that a mutual de-
compofition of both the gafes could be thus effeéted; but this
camot be accomplifhed; a diminution of bulk indeed takes
place to a certain extent, but the complete difappearance of
both the gafes cannot be effe€ted. If the admixture of arfe-
niated hidrugen, with this oxiginized muriatic acid gas, be
continued no longer than white clouds appear, and the refidue
be then examined, it will be found to confift of hidrogen and
oxiginized muriatic acid gafes; and the mixture detonates at
the approach of a taper. The oxiginized muriatic acid gas-
can only be feparated with difficulty by long agitation, in con-
taét with water, andit feems as if it were become lefs foluble
in that fluid. If the feparation of this gas be accomplifhed,
the remaining arfeniated hidrogen burns with a pure flame,
void of alliaceous odour, and contains no veftige of arfenic, as
fhall be proved hereafter. From what has been ftated, the
following theory may be formed.
Theory of the Arfenic, in combination witha certain portion of hidrogen,
decompofition of conftitutes arfeniated hidrogen gas. On prefenting to this
asfeniated hidto- — 4 bination oxiginized muriatic acid gas, the oxigen of this
rite! gas combines with the hidrogen, which held in folution the
arfenic, and the latter is feparated. If more oxiginized mu-
riatic acid be added than is neceflary for this purpofe, the por-
tion of oxiginized muriatic acid gas does not aét further upon
the hidrogen, but merely upon the arfenic, and the latter be-
comes oxidifed.
Arfeniated hi- Hidrogen and arfeniated hidrogen may be mingled without
drogen gas MiX* Jecompofing each other; the decompo.-tion can only be ef-
ed with hidro - C “ :
gen. feéted by the contaét of fire; but if we mingle hidrogen, hold-
ing in folution fulpbur and-oxiginized muriatic acid gas, the
decompofition and formation of water is inftantly effected.
This is likewife the cafe with arfeniated hidrogen gas.
Hidrogencom- Hitheriono combination of hidrogen with a metallic fubftance
bined with me- has been known; but it is highly probable, that fach combinae
tallic fubftances. . 2 ar 3
tions may exift. This indeed feems to be the cafe in the for-
mation of this gas on which we are treating. » If this be ad-
4 - mitted,
ARSENIATED HIDROGEN GAS, 905 i
mitted, a divifion of hidrogen muft take place, in the follow-
ing manner; one part of it muft unite with the oxigen of the
oxiginized muriatic acid gas, to produce water; another part
muft fall down with the arfenic; and another portion remains
combined with caloric, in the form of hidrogen gas.
Hydrothian acid gas * and arfeniated hidrogen do not aé Sulodiordees and
upon each other. Toa mixture of equal parts of hydrot Te ar aia
acid gas, and arfeniated hidrogen gas, I added gradually Qx- Oxiginized mu-
iginized muriatic acid §233 a diminution of volume inftantly ae pee
took place, accompanied with liberation of heat, and a depo-- NEE
fition of yellow fulphurized arfenic (orpiment). On adding
an additional quantity of gas, the precipitate acquired a beau-
tiful orange red colour, and on continuing the addition of ox-
iginized muriatic acid gas, white clouds were produced, the
precipitate detached itfelf from the fides of the veffel, and
were gradually converted into a pulverulent lnbitance ofa yel-
lowith white colour.
The refults of ‘thefe experiments are obvious, and might Teft of arfeni-
have been expeéted a priori. But they may ferve asa teft to #4 hidrogen.
difcover the prefence of arfeniated hidrogen, when contained
in other gafes,
| I mingled one cubic inch of arfeniated hidrogen with ten of Nitrogen mixed ©
"nitrogen, and one of hydrothian acid (fulphurated hidrogen With it.
gas;) on adding to this mixture a {mall quantity of oxiginized
_ muriaticacid gas, yellow fulphurized arfenic was inftantly de-
pofited. It is not improbable, that arfenic is likewife foluble
in other gafes, and in this cafe the hydrothian acid (liquid ful-
phurated hidrogen,) in conjunétion with oxiginized muriatic
__ acid, would provea ufeful re-agent for difcovering the prefence
of it.
A lighted taper immerfed ina vial filled with arfeniated hi- es 2
_ drogen, is inftantly extinguifhed; at the fame time that the mo niet’
_ gas burns at the orifice of the vial with a lambent white flame,
diffufing a difagreeable odour, and much white fumes, which
are arfenious acid. If the gas be inflamed in a phial with a
{mall orifice, the flame defcends gradually down to the bottom
of the phial, which becomes lined with a coat of cryftallized
In this cafe therefore the hidrogen alone
/
metallic arfenic..
_ burns.
_* The name given by the Germans to fulphurated hidrogen gas, on
account of its pofleffing the properties of an acid.
If
9206
Explodes with
oxigen.
Burns beauti«
fully in oxigen
Fase
Compofed of me-
tallic arfenic and
hidrogen.
Its habitudes to
acids.
Concentrated
nitric acid.
ARSENIATED HIDROGEN GAS:
If two parts of arfeniated hidrogen be mingled with thre
of dxigen, anda taper be prefented to the mixture, an ex
.plofion takes place; no metallic arfenic is feparated, but the
produ@ts are arfenious acid and water: foap-bubbles with the
mixture of thefe gafes, explode with a bluifh white flame,
leaving a white {moke and ftrong alliaceous odour. Equal
parts of arfeniated hidrogen and oxigen gafes, fired in like
manner, do not explode fo loudly, but the report is accompa-
nied with a much more vivid flame.’ A ftream of arfeniated
hidrogen, iffuing from a bladder fitted with a ftop-cock, and
fet to burn in a large receiver filled with oxigen, yielded
arfenic acid. The combuftion in this manner is uncommonly
beautiful; the gas burns with a blue flame of uncommon
fplendor:
Two parts of arfeniated hidrogen, and one ofoxigen gas, being
detonated in a clofe veffel by means of the ele@tric {park, left
a fmall refiduum; on repeating the experiment, the deto-
nating tube broke during the explofion, which prevented the
examination of the refidue. From what has been fo far re-
lated, it becomes evident that the conftituent parts of aFles
niated hidregen gas, are metallic arfenic and hidrogen. Were
it poflible to determine with abfolute certainty, that no ins
creafe of volume took place during the folution of arfenic in
hidrogen, ‘the proportion of the conftituent parts of this gas
might be afcertained thus : |
French weight and
meafure.
One cubic inch of hidrogen, weighs - 0,0353
One cubic inch of arfeniated hidrogen, weighs 0,2435
Deduéting the former from the latier, we get 0,2082
Which is the quantity of arfenic diffoived in the gas, confes
quentiy one cubic imch of arfeniated hidrogen gas, confifts of
0,0363 hidrogen, and 0,2082 arfenic ; and one cubic inch of
this gas contains about 4 grain of metallic arfenic.
Habitudes of arfeniated Hidrogen to Acids.
Into a phial, containing about eight cubic inches of ar+-
feniated hidrogen, I Boarea a half cine inch of concentrated
nitric acid. The moment the acid came into contact with the
gas.
ARSENIATED HIDROGEN GAS. 907
gas. The phial was filled with denfe red fumes, a white
flame pervaded the veffel, and a‘detonation enfued.
On repeating the experiment with dilute nitric acid, no pilure nitric
accenfion took place. The refiduary gas was pure hidrogen, “id.
and the water contained arfenic acid. Fuming concentrated
nitrous acid therefore is capable of oxidifing the arfenic con-
tained in this gas, at the fame time that the oxigen of the
acid burns with the hidrogen of the gas, and produces water ;
whereas weak nitric acid is only capable of oxidizing the are
fenic, without ating upon the hidrogen prefent.
Into.a glafs tube, furnifhed with a ftopper at one extre- Nitro-muriatie
mity, and clofed at the other, I introduced eight cubic aid.
inches of arfeniated hidrogen, to which were added two cubic
inches of nitro-muriatic acid. After having agitated the
_ fluids, on opening the tube under water, a diminution of one
cubic inch took place. The refiduary gas was pure hidrogen.
it isremarkable that, during the addition of the nitro-muriatic
acid, a black powder feparated, which again difappeared on
agitating the tube. Nitro-muriatic acid aéts therefore in the
fame manner upon this gas, as oxigenized muriatic acid gas.
It effects firft a feparation of the metallic arfenic, and then
oxiginizes this metal. Liquid oxigenized muriatic acid: de- Oxiginized mus
compofes arfeniated hidrogen by mere agitation; the refidue "tic acid.
is hidrogen. Muriatic acid exercifes very little aGtion upon Mutiatic acide
arfeniated hidrogen ; but merely diffolves a minute portion
of it, which may be expelled again by heat. Concentrated Concentrated
2 . : : acetic acid.
acetic acid has no effect upon it.
Into a glafs cylinder holding eight cubic inches of arfe- Concentrated
niated hidrogen, I poured one cubic inch of concentrated ful- fulphuric acide
phuric acid, and then clofed the tube. At the moment of the
addition of the acid, the cylinder became lined with a coat cyrious phenoe
of bright metallic arfenic, fo as to refemble a looking-glafs, menon.
On agitating the cylinder, the coating refolved itfelf intoa
_ brownifh black powder, which, after a few days, aflumed
the colour of Kermes mineral. On opening the cylinder un-
_ der water, a diminution of bulk enfued, and the refiduary
_ gas proved to be hidrogen. The experiment was repeated,
and yielded the fame refults. The fulphuric acid employed The fulphuria
in this experiment, had acquired a penetrating pungent fmell, acid examined.
and was examined, after having been neutralized by am-
-monia, in the following manner :
5 Ammo-
208 ARSINEATED HIDROGEN GAS,
Ammoniate of copper, on being mingled with it, acquired:
a greenifh colour. Hydrofulphuret of ammonia inftantly oc-
cafioned a copious yellow’ precipitate.
Water impregnated with fulphurafed hidrogen gas, occa-
fioned a fimilar effe@t.. From the refults of thefe tefts it be-
comes obvious, that the acid confifted of fulphuric, ful-
phureous and. arfenic acid. In order to be certain in this
refpect, I. mingled a few. drops of liquid arfenic acid with a
mixture of fulphuric and: fulphureous acid, neutralized the
fluid: with ammonia, and fubmitted it to the fame tefis. The
Rheory. refults of this mixture were analogous to the former. The
decompofition of the arfeniated hidrogen gas, is probably
analagous to the decompofition of this gas, by means of
oxiginized muriaticacid gas... The fulphuric acid firft gives ap
part of its oxigen to the hidrogen‘of the arfeniated gas, and
occafions the feparation of the arfenic.; which, at the ex-
pence of the remaining portion of oxigen of the fulphuric
acid, becomes afterwards onigeiiae, and conftitutes the
arfenic acid.
Itchabitudes Habitudes of arfeniated Hydrogen Gas to Metallic Solutions.
to metallic Mima uss atucey
ian lL caufed a current of arfeniated hidrogen gas, to pafs through:
Ammoniate of 4 (olution of ammoniate of copper. , A metallic pellicle ap-
eae: peared on the furface of the fluid, which fuffered no other
change.
Muriate of tin. Into a botile filled with arfeniaia hidrogen gas, I dropped
a folution of muriate of tin, On agitating the folution, it ac-
quired a brown colour, a partial diminution of the gas en-
fued, but the folution of tin was not converted into an oxi- _
dized muriate of tin, which would have been the cafe, if .
the arfenic exifted in the gas in an oxidized ftate.
Nitrate of lead. | Nitrate of lead, on being brought into contaét with ar-
feniated hidrogen gas, became turbid; and: ao a preci-
pitate, which was arfeniate of lead.
Nitrate of filver. Nitrate of filver fubmitted to the action of, the gas, became
inftantly of an intenfe black, and a pellicle of metallic filver —
. colleéted on the furface of the fluid. The refidue of the gas,
which had been made to aét on the oxide: of' filver for fome
time, had all the properties of pure hidrogen.-
A good teft. This experiment fhows, that nitrate of filver might be em-
ployed for deteéting the prefence of arfeniated hidrogen ; for
as
ARSENIATED HIDROGEN GAS, 2999
ss long asa minute quantity of arfenic was prefent, a black
precipitate enfued; whereas pure hidrogen has no effeét upon
this re-agent.
I paffed into a concentrated folution of nitrate of filver, a
fiream of arfeniated hidrogen, collected the black metallic
_precipitate, wafhed and dried it: The fluid obtained in this
procefs did not difturb the tranfparency, or change the co-
lour of ammoniate of copper. Neither liquid fulphurated
hidrogen, tinGiure of galls, nor potafh, had any effeét upon
it. It contained therefore neither filver nor arfenic. The
precipitate before obtained, acquired a metallic luftre on be-
ing faturated ; laid on ignited coals, it diffufed an odour of
arfenic, and it yielded by fufion a button of filver. It was an
arfeniate of filver. .
Arfeniated hidrogen paffed into a folution of nitro-muriate Nitro-muriate
of gold, occafioned a precipitate; on the furface of the of sold
fluid appeared a pellicle of metallic gold; and the fides of
the veffel, in contact with the fluid, became beautifully
gilded. The fluid through which the gas had been pafled,
examined in the ufual manner, proved to contain no veftige
either of gold orarfenic. ‘The precipitate greatly refembled
_ charcoal duft, interfperfed with minute particles of gold.
It is highly probable, that arfeniated hidrogen is capable of Decompofes mes
decompofing all metallic folutions, the bafis of which is either tallic folutionse
nitric, or muriatic acid, and probably other acids.
Habitudes of arfeniated Hidrogen Gas to various other Bodies.
Expreffed oils, on being agitated for fome time in contaét Its habitudes
with arfeniated hidrogen, abforbed part of the gas, and ac- © ee
_ quired a deeper colour.
Alcohol fuffers no change from arfeniated hidrogen, Solu- andto alcohols
tion of potafh, and liquid ammonia, do not abforb it. andealcditete
. Such are the properties of this gas, the inveftigation of
which I fhall continue as foon as my health is reftored, it be-
ing fo confiderably injured by the unavoidable inhalation of
this gas during the courfe of thefe experiments, which gives
me ample reafon to conclude, that the gas muft be highly
poifonous. )
D. J. B. TROMSDORFF.
Enfurth, Feb. 1803.
Vor, VI.—NovemBeER, 1803, r Account
Dr. Hope’s eu-
diometric appa-
yatus.
KUDEIOMETRIC APPARATUS.
VII.
Account of an Eudiometric Apparatus, contrived and ufed by
Dr. Horr, Profeffor of Chemifiry in the Univerfity of Edin-
burgh*.
SINCE the difcovery of the uncertainty with which the
application of nitrous gas to atmofpheric air, and other mix-
tures, containing oxigen is attended, it has been found de-
firable to prefent folid or liquid fubftances for the abforption
of that principle. This, on firft confideration, may feem
at leaft as eafy to be done, as to mix two gafes ; but it is by
no means fo, becaufe the liquids in particular poflefs a degree
of chemical a€tivity, which renders it inconvenient to im-
merfe the hands in them, or to expofe their furfaces to the
open air, efpecially when it is attempted to accelerate their
Operation by means of agitation, fo as to obviate the prin-
cipal objeétion to their ufe, the tardinefs of the procefs.
- The apparatus of Dr. Hope, which he ufes in his leétures
and in his experiments, is at once fimple aud effectual, and
I have the pleafure of inferting the following correét enone
tion with his permiffion.
The apparatus confifts of two bottles, which are repre-
fented in Plate XII, conneéted together in the manner in
which they are ufed; A reprefents a fmall bottle which may
be nearly two inches in external diameter, and three in length, '
having a neck and ftopper at D, and another neck as ufual at
C. It isdeftined to contain the eudiometric liquor. Brepre-
fents a larger bottle, which may be nearly of the fame dia-
meter, or rather of {omewhat lefs, but 82 inches long. The
neck of B is fitted accurately by grinding into the neck of
AatC.
The method of ufing this apparatus is very fimple: intro-
duce in the ordinary ‘way into the bottle B, the air or gas
* As the defcription at p. 61, of the prefent volume is in fome
sefpeéts inaccurate through hafte, and the figure, being an outline,
appears as if the neck of the upper veffel protruded fo far into the
lower, as to prevent the afcent of a portion of the gas after agi-
tation,—I have chofen rather to give an entire defcripticn and
drawing in this place, than adopt the lefs acceptable procefs of an-
gotating and correcting.
til
ZUDIOMETRIC APPARATUS. 911
ill it is full; then fill A with the abforbing liquor, for exam- Dr. Hope’s eu-
: a 3 : : diometric appa
ple with a folution of fulphuret of lime, which Dr. Hope jatys,
‘commonly employs, and covering the mouth with a flat piece
of glafs, plunge it under the furface of water, and there in-
fert the neck of B.
The compound veffel is then removed from the water, and
inclined till a fufficient quantity of the liquor flows into
B. It is now well fhaken, and the agitation ought to be con-
tinued till the abforption is compleated—Left the diminution
of the denfity, of the included elaftic fluid fhould retard the
abforption of the oxigenous portion; from time to time the
apparatus, in the pofition in which it is reprefented in the
figure, is to be placed ina plate full of water, and the ftopper
D is to be loofened, or fo far withdrawn, as to allow this
fluid to enter to fill the place of the abforbed gas.—By this
admixture of water the liquor is diluted, but not to fuch a
degree as in any meafure to interrupt the advancement of
the procefs, unlefs indeed when the gas abounds very much in
oxigen.
When a gas of this defcription is the fubje& of experiment,
it may be proper to ufe an apparatus, of which the bottle A is
made of greater capacity in relation to the fize of B, than in
the proportion already affigned.
As foon as it is obferved, that after reiterated agitation, and
opening the ftopper D, the liquor does not rife higher, the ab-
forption may be confidered as compleated, and the operation
may be finifhed by allowing the inftrument to regain its ori-
ginal temperature, in cafe, from want of due precaution, it
_ may have been affected in this refpeét by the warmth of the
hand in the courfe of the experiments.
If the bottle B be graduated, the amount of the abforption
may be determined at once, by plunging the apparatus into
water to the level of the included liquid, and removing the
ftopper, otherwife the refidual gas may be transferred into a
tube, exprefsly graduated for meafuring gafes.
- By this convenient contrivance, we fee that the liquid is
~economized and the celerity, neatnefs, and precifion of ex-
periment are enfured. The fize here mentioned is very well
adapted to the purpofes of publie exhibition, but it is almoft
~ needlefs to remark, that it may, and in general ought to be
made confiderably fmaller for the ordinary eudiometric expe-
riments.
F:2 Dr,
219
Apparatus for
drying precipi-
tates on the
water bath ;
APPARATUS FOR DRYING
Dr. Hope fuggefted that the apparatus might be made ftitt
more fimple without impairing its merits, in any confiderable
degree, particularly when fmall volumes of gas are to be ex-
amined, This is done by ufing a {mall bottle having one
neck only, and having a graduated tube nine or ten inches
long, and from half to three quarters of an inch in diameter,
accurately adjufted to fit into it, but not projecting into its
cavity.
If the bottle have twice or thrice the capacity of the tube,
the fame folution of fulphuret of lime may be repeatedly ufed,
and the abforption will be more expeditious.
In employing this inftrument, the manipulation is in all
refpeGts the fame as above defcribed, excepting when the
progrefs or termination of the operation is to be difcovered.
. For this purpofe, loofen the conneétion between the tube and
the bottle, in a degree fufficient to allow the ingrefs of the
water of the trough, in which the eudiometer muft then be
immerfed.
This apparatus equally unites difpatch, coeconomy of eudio~
metric liquor, and convenience of management.
IX.
Defcription of an Apparatus for drying the Produéts of Chemical
Analyfis which is alfo ufeful for Experiments of Congelation.
By Mr, FrepertcK Accum. Communicated by the In-
ventor.
"Tuts apparatus, Plate X. is extremely ufeful in drying
fuch produéts as abfolutely require a temperature not exceed-
ing 212°; fuch as fulminating mercury, Chenevix’s fulminat-
ing filver, and other explofive compounds. The fubftance
to be dried muft be placed in the conical glafs veffel B, and
when the veffel F is filled with water up to the fide tube D;
the deficcation may be performed without any rifk of ex-
plofion, or any further trouble, by putting the apparatus over
alamp, and keeping the water in a ftate of ebullition. (See
the lower drawing in perfpective.) I have found it particularly
ufeful in the deficcation of the precipitates obtained in the
analyfis of minerals, Itis well known that the fame mineral,
analyfed
CHEMICAL ANALYSIS, 913
analyfed by different chemifts, has been found to yield dif
ferent proportions of the fame ingrediants, and that the
difference of proportions of the conftituent parts, in many
cafes, is often more apparent, than real; arifing entirely
"from the various degrees of deficcation that has been employed
by different analy{ts, and fometimes even by the fame perfon.
This point is of fuch importance, and is productive of fo
much trouble, that every chemift who has analyzed a mineral
water, or cryftallized and feparated {mall quantities of deli-
quefcent falts, will at once perceive the utility of the ap-
paratus in this re{pect.
This apparatus may likewife be ufed as a water-bath. In The fame ufed
that cafe, the conical glafs veffel B is removed, and the inner 4S 4 water bath
tin velfel E filled with water ; into this, retorts, flaiks, galli-
pots, vials, bottles, &c. may be immerfed for promoting the
proceffes of diftillation, digeftion, folution, evaporation, &c. é
or it may be ufed asa fund bath, (it being hard foldered) by or fand bath. .
filling the tin veffel with fifted fand, for performing thofe
operations which require a higher temperature, than that of
boiling water.
When the inflrument is required to be ufed as a freez ing Method of freez~
apparatus, the bottom cover G is to be taken off, and the Hes (mercury
for example)’ by
cavity between the interior, and exterior veffel, filled with PRR 62S
the frigorific mixture ; a wetted piece of bladder is then to
be tied over the opening, or the cover is put on, to retain
the mixture. The fecond frigorific material (for inftance if
quickfilver is to be frozen) confifting we wil fay, of muriate
- of lime and fnow, are to be cooled by the mixture in the
exterior veffel, by putting the muriate of lime into the conical
glafs veffel, together with the mercury contained in a thin
glafs tube; and furrounding the glafs veffel, by filling the
interior tin veffel with fnow, or pulverized ice. When thefe
‘materials have been cooled down to 0°; the fnow and ice
may be mixed together by emptying the muriate of lime into
the veffel containing the fnow, and ftirring the mixture with
a glafs rod to facilitate the folution of the falt, and to produce
the requifite degree of cold. The number of apparatus I
have fold to philofophical chemifts, gives me reafon to fuppofe,
that they have proved ufeful.
FREDERICK ACCUM.
11, Old Compton Street,
Soho.
Letter
914 PROCESS FOR OBTAINING THE AGUSTINE EARTH.
xX.
Letter from Mr. Accum, in anjwer to the Enquiries of a Cor-
refpondent refpeciing the Procefis for obtaining the Agufiine
Earih.
To Mr. NICHOLSON, °
DEAR SIR,
Miftake refpe&t- Your correfpondent, P. O. in the laft number of your
ing the publics: Journal, is correé&t, when he obferves, that the procefs for
tion of the ase é 4 ; :
method of ob- obtaining aguftine earth is not noticed in my fyftem of prac~
taining a8%s= tical chemiftry, nor in any other work publifhed in this coun-
tine earth.
iry, and alfo that moft of the books he quotes, were pub-
lifhed a confiderable time after this earth was made known
by profeffor Tromsdorf; but he is miftaken in his opinion, that
it was known in this country previous to the publication of
the above works.
Firft account. The method of feparating this earth from the mineral which
contains it, had not then been communicated to us through
~ the ufual channels of fcientific information. - The firft account
of the method of feparating this earth I can find, is contained
in agerman work, entitled Prediijche Anleitung zur zerlegenden
Chiemie, publifhed by Profeffor Géetling, 1802. From which
the following tranflation is made.
oS ee Let a determinate quantity of the Saxon beril finely levi-
pieces, boiled gated, be boiled in a filver vellel, with three or four times its
with potah; weight of potath, diffplved ina fufficient quantity of water ;
sie Oe evaporate the whole to drynefs, and fufe the mals.
aR aN Soften the alcaline mafs by the gradual addition of water,
ees as and when detached from the crucible, add to it muriatic acid .
evaporated to till the whole is diffolved. Evaporate the folution to drynefs,
with waers and Boil. the mafs in-a fufficient quantity of water, and feparate
the filex fepa- the infoluble refidue [filex ] by the filtre.
Bees ie Decompofe the fluid from which the filiceous earth has been
cipitated by car-feparated, by gradually mingling it with a folution of car-
bonate of foca; bonate of foda; colleét the precipitate, and wath it re-
peatedly.
feparate the When the precipitate obtained in the laft procefs has
amapune too) acquired fome confiftence, transfer it into a flafk containing
the precipitate , ; i
by potath whicha concentrated folution of potafh, The alumine which was.
diffolves it and i
e1e
Jeaves the agus pr fent-
tine carthe
METHOD FOR CLOSING WIDE MOUTHED VESSELS, 916
prefent in the mineral, will be diffolved*, and the infoluble
refidue left, is the new earth called Agufine.
It is diftinguifhed from all other earths by being teddy Charaéters of
iMfoluble in potafh, foda, and ammonia, and all their car- this earth.
bonates. Nor can an union of either of the two firft al-
calies with Aguftine be effected by fufion, It is foluble in
acids, with which it forms falts, which have little or no tafte,
It is foluble in acids with equal facility after having been ig-
nited, as when frefh prepared. It fufes with borax into a
tranfparent colourlefs glafs.
100 parts of the Saxon beril yielded Profeffor Trom(dosf
78,0 Aguftine, 4,5 alumine, and 15,0 filex.
lam, Sir,
Your moft obedient,
FREDERICK ACCUM,
11, Old Compion Street, Soho,
15th Odober, 1803.
a er ee ae ee
XI.
Letter Jrom a Correfpondent concerning the Method propofed by
Mr. Carlifle for clofing wide-mouthed Veffels.
Odtober 15, 1803.
STR,
In the laft number of your Journal, publifhed on the firft of The method of
this month, page 68, I find a letter addreffled to you by Mr. te uetehs
uggefted in our
Carlifle, defcribing ‘<a method of clofing wide mouthed =< lat number
fels intended to be kept from communicating withthe air ;’
and in Plate V. Fig. 2, there is an engraving of the veffel re-
* It is perhaps needlefs to ftate that the alumine may be feparated
from the alcaline folution, by faturating it with muriatic acid in ex-
ce{s, fo as to neutralize not only all the potath, but alfo to diffolve
the alumine, and then to decompofe the obtained folution by car-
bonate of ammonia. Should glucine be expeéted, the carbonate of
ammonia fhould be added in confiderable excefs; for the excefs of
ammonia retains in-folution the glucine, and nothing but alumine
will be thrown down. The glucine may be obtained by evapo-
4ating the folution to drynefs and igniting the refidue,
F. A.
coms
916
APPARATUS FOR RAISING WATER IN WORM TUBS,
commended ‘by the above ingenious gentleman. But I muft
beg leave to obferve that this, which in your Journal is deno-
- minated ‘‘a new method, by a jar, the cover of which fits
Was ufed by
Buffon ;
and by Le Cat;
nd before all by
Glauber.
Apparatus for
more eafily
raifing water in
worm tubs, by
atmofp eric
preflure.
into a groove with hog’s lard,” is in reality a very old method ;
for in the quarto edition of Buffon, publithed at Paris in 1749,
Tome III. p. 192, you will find many fuch veffels reprefented,
and Fig. 4, is precifely the fame as the one given in your work.
But Buffon was not the inventor of this method, for it is
claimed bythe celebrated Mr. Le Cat, who had glaffes made
upon this conftruétion about the year 1739, and in 1748 fent
to the Royal Society a defcription, which, with an engraving,
may be feen in the 46ih volume of the Philofophical Tranf-
actions, page 6.
But even the celebrated Mr. Le Cat was not the inventor,
for old Glauber employed this method long before, and a
plate and defcription may be feen by any one who will take the
trouble to confult his ** Fornacum Philofophicarum, pars quinta,”
page 13, &c. &c. publifhed at Amfterdam in 1661. The
only difference is, that Glauber ufed quickfilver -to fill the
groove; Mr. Le Cat employed quickfilver, or oil; and Mr.
Carlifle recommends hog’s lard. If you think thefe remarks
worthy of a place in the next number of your Journal, they
are much at your fervice; from an
se Fi OLD CORRESPONDENT.
XI.
Account of an Experiment for fupplying Worm Tubs and other
Refrigeratories by the afifiant Preffure of the Atmofphere, which
proved unfucce/iful, ona large Scale; to whichis added an Im-
provement for extending the ufeful Applications of the Syphon,
By Epwarp Howarp, Esa. FLR.S. In a Letter to the
' Editor. ; .
To Mr. NICHOLSON.
SIR,
‘Tue method of fupplying worm tubs and condenfers, given
by Sir Alexander Edelcrantz in your laft number, induces me
to trouble you with the refult of an unfuccefsful experiment,
which I fome time fince made on much the fame principle,
and
APPARATUS FOR RAISING WATER IN WORM TUBS. O17
and ona worm tub of a confiderable fize. Indeed it was my
firft intention to have made the worm tub part of the arm of a
fyphon; but, as warm water was conftantly wanted in’ an
elevated part of the premifes, and asall the water ufed was
raifed by a lifting pump from an adjacent well, an opportunity
appeared to prefent itfelf, both of economizing labour, and of
making ufe of the warm water of the upper: furface of the
wormtub. To effeét thefe objeéts, I made the pipe coming
from the well immediately communicate with the tub, and an-
nexed the pump, by means of another pipe, to the upper fur-
face of the tub. By this conftruétion, there was every reafon
to conclude that it would be praéticable to pump off the warm
water, and alfo, that whenever the pump was worked to fupply
the other demands of the laboratory, the water in the worm
tub would be conftantly changed without additional labour.
It was further thought neceffary to add a valve of fafety to the
upper part of the tub, and two {top cocks, one on the pipe
leading from the well to the tub, and the other on the pipe
leading from the pump to the tub, in order that by the regula-
tion of thefe cocks, water might be had either immediately
from the well, for other purpofes of condenfation, &c. or it
might be drawn from the worm tub for proceffes requiring
warm water, or for ufes to which warm or cold water might
be indifferently applied.
To give a better idea of the apparatus, I have fubjoined
the following outline, Plate XII. where A reprefents the worm
tub; B a pipe leading from the weil; C a pipe communicating
immediately from the pump; D a valve of fafety, E a pump;
F a well; and GG ftop cocks.
The apparatus when made upon a fmall fcale, with a The apparatus
Woulfe’s bottle and glafs tubes, anfwered perfeétly and pro- ane Ae per=
: bis te . eétly in the
mifed to be a valuable acquifition. I with I could relate the fmaij way; but
fuccefs of tie fame experiment made upon a large one: But, a on a large
notwith{tanding the beft workmen in London were employed, iach
they could not make the joints of the worm tub fufficiently
tight to refift the preffure of the atmofphere for more than a few
fucceffive hours. | .
I fhould not, Sir, have offered to you the refult of an un-
fuccefsful experiment were it not from an apprehenfion that
the worm tub recommended by Sir Alexander Edelcrantz might
be no lefs difficult to conftruét than the one I have defcribed.
Allow
218
OF EQUALIZING THE MOTION OF A STEAM ENGINES
Improvement in Allow me, Sir, to take advantage of this opportunity to
the fyphons
communicate what I believe to be an improvement of the
fyphon. It was made at the time I had an idea of applying
the principles of a fyphon to the worm tub: Although it may
not be applicable to this purpofe, it wil! be found exceedingly
ufeful in cafes where it would be difagreeable, dangerous, or
impoffible, to exhauft the fyphen by the common mode of
fucking -out the air, if I may be allowed fuch an expreflion.
I think it even probable that fyphons of confiderable dimen-
fions may be introduced for emptying ponds, or for lowering
the water in mill-dams or canals; fer it is without doubt de-
firable to avoid cutting through an embankment, and a very |
Jarge inftrument of the new conftruGion would be thus put in
action with great eafe. The improvement, Sir, I have thus.
ventured to fpeak of confifts merely in enlarging the exhauft-
ing pipe to the fame calibre as the reft of the fyphon; in ele-
vating it a little, and in opening its mouth like a funnel. See
Fig. 3. Plate XI.
It is fcarcely neceffary to point out that, to ufe fuch a fy-
phon, the fhort arm is, as ufual, to be immerfed in the liguor
intended to be operated upon, and the aperture of the long
arm to be clofed whilft the whole infirument is to be filled’
through the funnel with fome of the fame liquor.
Tam,
SIR,
Your obedient humble fervant,
EDWARD HOWARD.
XTi.
\
A Method of equalizing the Motion ef a Steam Engine without the
Affjiance of a Fly Wheel. By Mr. ARvHuR Woour, Er-
gineer, Communicated by the Inventor.
Equalizing me- "Tue mechanifm here prefented as a fubftitute for the fly,
chanifm which
allows the engin
. pofleffes the advantage of equalizing the motion, with the
to fet off or ftop power of being ftopped and fet to work at any part of the
in any part of
the ftroke.
firoke, the utility of which, in mines, collieries, and other
works, will be immediately fegn by thofe converfant in fuch —
undertakings.
Plate
IMPROVEMENT IN MR. E. WALKER’S QUADRANT, IQ19
Plate XI. Fig. 1. A reprefents’ part of the engine beam ;
B the conneéting rod; C the crank atm; D a cog-wheel,
working into another cog-wheel F, of half the fize; F acrank
arm on the fhaft of the {mall wheel; G a cylinder clofed at
bottom, in which afolid or unpertorated pifton moves, leaving
a vacuum beneath. This aéts fimply inftead as a weight on
the crank F, by the conftant preffure of the atinofphere; and
the diameter of the pifton muft be fuch as nearly to equal one
third of the power of the engine.
In Fig. 2. the outer circle is the line defcribed by the:crank;
the De ialstteieate of the inner circle is equal to twice the
diameter of the outer, and the fquare has the fame cir-
cumference; this laft exhibits the inequality ftill remaining,
which by this method is reduced to about one fifth ; but by the
affiftince of a {mall fly on the fecond motion, the effeét will
become nearly the fame as that of a rotative engine, with the
advantages here mentioned.
The fame motion may be applied toa pump, but inthis cale
the two cranks muft be horizontal at the fame time.
———
. XIV.
Improvement by which the additional Arc in Mr. Ezekiel Walker’s
' reflecting Quadrant is rendered unwecefary. In a Letter from
the Inventor.
To Mr. NICHOLSON. I
STR,
Ayy one who has a juft idea of the refleéting quadrant, bane!
defcribed on page 218 of the fourth volume of your Journal, aes
will perceive that one half of the arc of that inftrument is quadrant.
appropriated folely to the reétifying of the fecond horizon glafs.
_ This method of adjufting is as good as any other that I have
to propofe, but it is attended with the inconvenience of adding
to the fize of the inftrument, and confequently to its weight.
The following method of adjufting the fecond horizon glafs
will reduce the inftrument to an o@ant, which will ftill poflefs
the fame property of meafuring any angle lefs than 120° by
the fore obfervation.
Firk
990) IMPROVEMENT IN MR. E. WALKER’S QUADRANT,
Improvement ; J :
ae hides Firft, let a fmall mirror be fixed upon the top of the index
ker’srefle@ting glafs. This reétifier muft be placed parallel to the firft hori-
quadrante zon glafs, when the index ftands at 90° on the arc, confe-
quently the index glafs and reétifier will form an angle of 45
degrees. Secondly, let the two horizon glaffes ftand as high
above the plane of the oétant as the reétifier, and the inftru-
ment is ready for ufe.
After the firft horizon glafs has been adj ufted, Apr the in-
dex to 90, and the ee will be parallel to the horizon glafs,
if the index glafs and reétifier form an exaét angle of 90° on
the arc; but if they do not form that angle, the index will
fhow the error." Then to determine the error of the fecond
horizon‘ glafs, let the index be brought to 0, and the rectifier
will in that fituation perform the fame office as the index glafs
in the quadrant, when the index ftands at 90 at N; but as this
has been fully explained in the defcription of that inftrument,
it need not be further infifted on here.
An oétant of five inches radius, conftru€ted on thefe prin-
ciples, would be exceedingly portable, and fo ftrong as not
to be eafily deranged by carriage; and thefe are properties
which may recommend it to the attention of the traveller by
land, particularly if he vifit thofe latitudes, where the altitude
of the fun fometimes exceeds 60 degrees.
Thefe two glaffes may alfo be added to the fextant, without
depriving it of any of the valuable properties which it now
poffeffes: and this additional apparatus need only be ufed in
taking fuch angular diftances as are beyond the power of that
inftrument.
] am,
SIRs) +;
Your’s refpectfully,
| E. WALKER,
Lynn Regis, Odtober 15th. 1803.
Plate X1. Fig. 3. AB reprefents the index glafs; C D the
rectifier; m the horizon glafs; » the fecond horizon glafs.
SCIENTIFIC
SCIENTIFIC NEWS. é 99)
SCIENTIFIC NEWS.
Abjtract of Cit. Secu1n’s Inquiries concerning Fermentation *.
In is firft paper Cit. Seguin explains the plan of inquiry he Fermentation
has undertaken concerning fermentation in general; and more sabi by
particularly concerning the making of beer, wine, cider, malt fubftance, but
and melaffes fpirits, &c. In his fecond his objeét is to prove, a ee
that fermentation is not produced by .a fubftance fui generis, ftances.
but by a combination of circumftances.
He fhows, that, in the cafe of clear liquors fermenting, the Hit wee an de
true folvent of the fermentefcible caufe, whatever it he, is Pt at
water, and not the faccharine matter; that the continuance caufe,
of contaét, and the prefence of fugar, are by no means necef- pi par necilys
out the
fary for the folution of any fermentefcible principle in the prefence of
yeaft; that this folution is made by water in a very fmall Shen,
quantity, it is true, but almoft fuddenly, and even in the
ordinary temperature of the air ; finally, fuppofing fugar alfo
to poffefs the property of diapivag any given fermentefcible
principle, it would be impoflible to demonftrate this, fince,
to render it perceptible, the fugar muft previoufly be diffolved
in water.
—— ee
Additional Experiments of Mr. Rirrer, of Jena, on Galvanic
Phenomenat.
NATURAL philofophers will learn. with pleafure, that
Mr. Ritter continues his elegant experiments on a fubjcé, to
the progrefs of which he has fo greatly contributed. As they
all relate to a known theory, we fhall content ourfelves with
giving the refults as communicated to us by Mr. Ortfted,
leaving to the experamentalift the tafk of proving them with
all the requifite minutenefs.
The obje& of Mr. Ritter being to compare the eleétricity Mr. R’s obje&
of Voltas’ pile with that of eleétrical machines, he confiders Volta’e pile with
fucceffively the intenfity of eleétricity, chemical action, fpark, eleétrical ma-
and fhock, in the pile. chines’
* Bulletin des Sciences, No. 75:
+ Bulletin des Sciences, No. 77.
599 SCIENTIFIC NEWS
Ele€tricity pofi- As to the intenfity, we know that the eleétricity is pofitive
plats rg at one of the poles of the pile, and negative at the other ; it
negative atthe has been fhown likewife, that it diminithes between thefe
oe ge: be. two extremes, fo as to be null in the middle of the pile.
tween them, Mr. Ritter fought to compare the degrees of intenfity at thefe
ae ne two poles, and thofe of different piles. This he attempted _
The time by determining the time neceffary for charging a given battery ;
neceflary for but this method is inaccurate, and no certainty can be at-
sheeue in- tained in this refpeét, but by means of the eleétrical balance.
accuratemeafure” According to Mr. Ritter, the aétion of the pofitive pole
ainda of Of the pile difpofes metals to combine with oxigen, and that
the pile difpofes of the negative pole difpofes them to combine with hydrogen.
oak com- If the pofitive pole be armed with a gold leaf, and the nega-
oxigen, tive with a bit of charcoal, on forming a communication be-
—with hidro- tween thefe two fubftances the leaf of gold burns with a
oe le armed Drilliant light, and the charcoal remains untouched: but if
with gold leafy the charcoal be placed on the pofitive fide, and the gold on
a) yan tive, the charcoal b d the gold is melted
on forminga the negative, the charcoal burns, and the gold is melted.
communication Tf the negative pole be brought into contaét with the fhining
pclaate leaf 4S furface of quickfilver, it leaves a trace different from that
3 .
if the charcoal produced by the pofitive pole.
Lt 9 cage Mr. Ritter afferts, that all the effeéts of the pile on the
ur. . = =
he gold is animal body are reducible to expanfions and contraétions.
ae eee All the parts of the human body affume an increafed bulk on
Bess the contaét of the pofitive pole, and contraét on the contaét
with quickfilver of the negative: for inftance, the aétion of the pofitive pole
rk on ; . - ~
eee ie on the tongue produces there, at the expiration‘ of a few
ferent from that minutes, a flight elevation, whereas the negative pole oc-
Se a cafions a litte depreffion. If the fame perfon touch the
pile on the ani- two poles with the two hands wetted, the intenfity of the
prscecbaa pulfe is increafed in the- hand in contaé with the pofitive.
panfions and pole, while its ftrength is diminifhed in the other, but the
Pemeige number of pulfations continues the fame in each. The ex-
creafing the bulk panfion thus produced in the organs, is attended with a
of parts, the fenfation of heat, the contraction with a fenfe of cold.
diminifhing ite i . }
Eficéts on the If the eye be made to communicate with the pofitive pole,
tongue, it fees objeéts red, larger, and more diftinét; in contaét with
he expantoe “the negative pole it fees them blue, fmaller, and more con-
occafions a fenfe fufed. The tongue receives. from the pofitive pole an acid’
of heat, and tafte, from the negative an alcaline. The ear being in con-
vice verfae |
To fhe eye the tach
SCIENTIFIC. NEWS. 293
ta& with the former, all founds feem more grave: with the BEL gine
A objects re
latter, more acute. | large & diftin@ ;
In general the two poles of the pile produce oppofitethe —, blue,
{mall, and cone
effe&s. fufed
Such are the refults of Mr. Ritter’s experiments: We have + gives an acid
no opportunity of verifying.their accuracy ; but their fingu- ge ree
larity, their number, and particularly the ingenuity of their fodeidet
author, lead us to prefume, that this account of them il Nene
. emé
- be read with pleafure. The two poles
SOCIETE PHILOMATH. nally pro-
duce oppofite
effects.
EE
Abjirad of fome Remarks on the Acetile of Lead, by
Cit. THenarp *,
A MANUFACTURER of acetite of lead was obliged to A manufacturer
ftop his works, being no longer able to make the falt cryf- bts Sod fop
tallize in needles, but always obtaining it in laminze, which caufe render
induced purchafers to refufe it} Cit. Thenard inquired into of lead Wie al-
the caufe of this phenomenon, and foon perceived, that it Po aenes
was owing to the proportions of the conftituent principles
of the falt. He fucceeded in forming a falt perfeétly fimilar
to it, by boiling in water a hundred parts of the acetite of
lead of the fhops, with a hundred and fifty parts of litharge
well dried, and deprived .of carbonic acid by means of fire,
Analyfis corroborated the exiftence of two fpecies of acetite Two fpecies of
of lead; one, long known, confifts of oxide of lead Bose, Ma dea
-acetous acid 0.26, and water 0.16, the other, which has
hitherto efcaped the notice of chemifts, contains oxide of
‘lead 0.78, acetous acid, 0.17, water 0.05.
The former of thefe falts has an excefs of acid, and a ftrongly The commen or
faccharine tafte; cryftallizes in needly prifms, which appear ae ems
to be hexagonal, and terminated by hexaedral pyramids ;
_ undergoes no alteration in the air; is very foluble in water,
and forms with it a folution feebly precipitable by carbonic
acid. Thelatter, on the contrary, is neutral ; has a lefs per- The new 6r
ceptible faccharine tafte ; affe@ts a lamellated figure ; is foluble esta aaals
in vinegar, and then exhibits on evaporation the needly form ;
. * Bulletin des Sciences, No, 77.
efflorefces
224
Fine white lead
may be prepared
froin it.
; QCIENTIFIC NEWS. iN
efflorefces flightly in the air; is much lefs foluble in water,
but forms with it a folution abundantly precipitable by
carbonic acid. This precipitate is very white, forms a pafte
with oil, and by extracting the carbonic acid from chalk by
_means of fire, it would perhaps be pofflible to prepare a fine:
Advantages of
the difcovery.
white-lead by thefe means.
Fhe value of the difcovery of this falt, will be readily
perceptible. It not only brings us acquainted with a new
fubftance interefting in a fcientific view, as it affords us a frefh
proof, that the proportions of the conftituent principles of
falts may vary greatly ; but it is likewife of importance in the
art of phyfic, in which falts of lead are daily employed, and
which may require one containing a large proportion of oxide;
and it is of confequence to the arts in general, as it affords a
new method of obtaining a fine white-lead, and particularly
‘ to that of manufa@uring acetite of lead, on the proceffes and
Arachis hypo-
gea cultivated
in France.
Affords an oil
excellent for
y2™mp Sy
and other pur-
pofes.
produéts of which it throws great-light.
ee
The Arachis Hypogea, or Ground Nut of the Weft Indies, cul--
itvated in France for its Oil.
IN the departments of Landes and lHerault in ae
lat. 435° to 442°, an oily plant, called arachis, of the family
of lentils, (arachis hypogza) begins to be cultivated. It was
brought by the Spaniards from Mexico, and was introduced
by the French from Spain. An ouncc of the oil of this plant,
with a wick a line and half in diameter, burned nine hours”
and twenty-fix minutes; an ounce of olive oil under fimilar
circumftances, lafted only eight hours. Thus the. oil of. the.
arachis has the advantage of more than one eighth oyer olive
oil; and it has more or lefs over every other kind of oil.
It is an excellent fubftitute for olive oil for every domeftic
purpofe, and is preferable to all other oils for the manufa@ture
of foap. The feed yields nearly half its weight of oil.
rnc EE ITT re
** The enquiries of a correfpondent, refpeéting the method.
of experiment adopted by Dr. Irvine, will be anfwered in
our next, 4,
PSomla oe)»
JOURNAL’ pikes
eadons Cth sce fe gin
- Natumat. PHILOSOPHY, CHEMISTRY,
*
AND.
ua 5 ak
D ECEMBE na 1803.
he eR DES Ea
Letter “Pith ie DREW een M.D. F. BS: ‘E., contains -
~. ng Experiments and Objercations én: Cinchona,- tending partis.
weet to Shew that tt does not contain Gelating. ect aityhao}
‘To. Mr. NICHOLSON. tein
ip Re : pditiond Se bi i
: Havine G been Biba enisatied i in a, ven af experiments on ',
_ the aftringent, iilapans employed: in medicine, .I was parti-
/ cularly interefted with the « Abfira@ of a Memoir onthe Fe-
brifuge principle of Cinchona,” contained in the laft number
of your excellent journal. The prefence of gelatine in cih- Prefence of gee
.chona, was fo,incompatible, with experiments I had formerly, ae in be
- made, that I.was ftrongly,.inclined to believe, : ‘that. Seguin take.” a a
(than whom no one fhould be better. acquainted with the coms’
_. binations of tannin and gelatine) had been mifled, either from
_ having examined cinchona which | had been adulterated, or
_ from fome other accidental caufe. To fatisfy myfelf I imme-
ss d.diately proceeded to’ the unerring ‘teft’ of experiment, which:
* has convinced me’that:cinchona doesnot contain gelatine, but Burl it contains
“fome: other principle not yet fufficiently examined, which: *, rhe) prin-
_, Agrees with gelatine, in forming with tannin, a. precipitate & “aidglnble' pre»
4 “ Comparatively infoluble in ‘water. At the fame time it is butcipitate with
. fair to remark, that my experiments were made with the in- orig
Vor. VI.—DrcemBER. Q fufion
226
Infufion and
tin¢ture of cin-
chona, preci-
pitate folutions
of tan, gela-
tine, and ful-
phate of iron.
Experiments ix
proof of this.
Infufion of galls
precipitated by
infufion of cin-
ehona.
‘Gave a further
precipitate with
gelatine.
infufion of
galls precipi-
tated by gela-
tinge
EXPERIMENTS AND OBSERVATIONS ON CINCHONA,
fufion and tinéture of cinchona, containing all ‘the foluble
principles of that fubftance, whereas Seguin’s obfervations
are faid to be derived from the examination of the ifolated fe-
brifuge principle, of which he gives the following charaéters :
** It precipitatesthe folution of tan, but not the folutions of
gelatine and fulphate of iron.” On the contrary my experi-
ments teach me, that the entire infufion and tin@ure of cin-
chona, precipitate the folution of tan, and alfo the folution of
gelatine flightly, and the folution- of fulphate of iron’ co-
pioufly. But as the two laft precipitates may be reafonably
afcribed to the aétion-of other principles contained in my in- |
fufion and tin@ure of cinchona, I. fhall not infift upon them,
but proceed to fhew that, although ‘cinchona actually does pre-
cipitate the folution of tan, yet it does nof contain gelatine.
- Experiment I.
(a) An ounce of infufion of galls was faturated, by adding
to it in different portions, an ounce and a half of infufion of
cinchona. The mixture was white and turbid, with a loofe
light precipitate. ;
(6) On filtration the fluid paffed almoft re and._-per-
feétly tranfparent.
(c) The precipitate when dried, weighed. Gee) grains. It
had a yellow colour, and an opaque earthy appearance, was
extremely friable, and did not adhere to the filtering paper.
(2) The filtred fluid gave no further precipitate with folu-
tion of cinchona, but with half an ounce of folution of ge-
latine, containing fix grains of gelatine in each ounce, it pro-
duced a copious precipitate, and was faturated.
(e) The precipitate, when feparated by filtration, and dried
alfo, weighed five grains, but was hard and brittle, adhered
ftrongly to the paper, had a yellow colour, and exaétly re- |)
fembled a refin in appearance.
Experiment II.
-.(a) An ounce of the fame infufion of galls was faturated by
an ounce and ahalf of the fame folution of gelatine. Imme-
diatelya very copious, whitifh, tenacious, and adhefive pre-
cipitate was formed.
(b) On filtration the fluid paffed very flowly, and even after
repeated filtration, ftill Retained a flight, degree of opaline
bluifhnefs.
(c) The
¢
EXPERIMENTS AND OBSERVATIONS ON CINCHONA, OFT
(c) The precipitate when dwed, weighed fourteen grains
and a half, It had a brownifh yellow colour, was tranfparent,
and had a refinous appearance and fra@ture. It was alfo hard
and brittle, and adhered ftrongly to the filter. In every par-
ticular it refembled the precipitate produced in the former ex-
periment (Exp. 1. e.) by gelatine, after the infufion of galls
was completely faturated by cinchona,
(d) In the filtred liquor (£xp. II. 6) infufion of cinchona Infufion of cins
produced no change. Pie
Experiment III. wii’
To an ounce and a half of the fame infufion of cinchona, Infufion of cine
half an ounce of the folution of gelatine was added. It pro- bee oS eure
: ; atine gave flight
duced only a flight degree of turbidnefs, and changed the co- fgns of tannin.
lour of the infufion from a pale greenifh to a reddith yellow co.
lour. When filtred, it paffed perfeétly tranfparent, and the
bottom of the filter was covered with a red varnifh; but it
had gained only one grain in weight. In other experiments
with larger quantities and ftronger infufion of cinchona, the
prefence of tannin was more ftrongly indicated.
Experiment IV.
| Infufion of galls was not affected by reétified fpirits of wine, Infufion of galis
in which ifinglafs had been long infufed. ee ese
' folved in al-
Experiment V. cohol!
(a) A tinéture of cinchona was prepared by infufing it in Tin@ure of ©
the fame reétified fpirits. After it was filtred fome refin was a
feparated by precipitation with water and filtration. ter,
(6) With infufion of galls this tinéture gave a copious pre- and by infufion
cipitate, exaétly refembling that produced by the fame re- of galls,
agent and infufion of cinchona. (Exp. I. ¢.)
Experiment VI.
With tin@ure of galls the fame tinéture of cinchona gave Tinéture of
Me galls and of
no precipitate. cinchona gave
no precipitate,
Experiment VII.
In the mixed tin@ture (Erp. VI.) a copious precipitate was till diluted by
| produced by diluting it with water. aaa
Q2 Experiment
\
998 EXPERIMENTS AND OBSERVATIONS ON CINCHONA-
Experiment VIII.
Carbonate of A folution of carbonate of potafh produced a copious
he aha white flaky precipitate in the folution of gelatine, which was
of gelatine, foluble in boiling water, but was not precipitated from the fo-
; lution by infufion of galls, until fome acid was added.
Experiment IX.
but not infu- The folution of carbonate of potath changed the colour of
pr ssa the infufion of cinchona to a fine red, without difturbing its
tran{parency.
Difference be- —'Thefe faéis feem to me fufticient to prove the difference be-
tween gelatin : ae Ea :
Ane Sean tween gelatine, and the new principle in cinchona, which fdr
the fake of convenience, I fhall venture for the igang to des
nominate cinchonin.
pee tied a Gelatine is foluble in water, and the folution is difpofed to
Ee ee gelatinize. Six grains of ifinglafs, diffolved in one ounce of water,
form with it at temperatures below 60° Fahrenheit, a jelly of
oe. confiderable firmnefs. From its folution in water, gelatine is
& alcohol, car- Precipitated by alcohol, and a folution of carbonate of potafh.
bonate of pot- It is precipitated alfo by tannin, and the precipitates form a
ath, and tannine 14d brown tranfparent mafs,
Cinchonin does = Cinchonin is foluble in water, but gives it no tendency
oh gage to gelatinize. From its folution in water, it is not preci-
not precipi- _ pitated by a folution of carbonate of potafh. It is fuluble in
ee alcohol ; it combines with tannin. The componnd is foluble
is folubleinal- in alcohol, but forms, when water is added, or ufed as a men-
regen ftruum, a friable opaque yellowith precipitate ; but cinchonin
fnnin, does not feparate even from a watery folution of tannin, all
that is precipitable by a folution of gelatine.
ANDREW DUNCAN, Jun.
Edinburgh, 30th O&. 1803.
IL. Letter
ON THE PHAN‘TASMS OF NICOLAI. — 999
3% ‘
Letter from a Correfpondent, containing Difquifitions on the Phan-
tajms of Nicoxrat, and other Derangements of the Animal
Syftem.
To Mr. NICHOLSON,
SIR,
‘Tue account publifhed in your laft number by Mr. Nicolai, The -phantafms
of his feeing fpeétres, appears not only to admit of an ex- “ ae ae
planation on feme of the laws of vifion with which we are
_ already acquainted, but may alfo lead to fome rational account
of the grounds, on which the belief in apparitions, which has
fo generally prevailed in all ages of the world, may be founded.
_If we look for a moment at the fun, and afterwards turn Kies oa a8
our eyes on the blue fky, or throw them upon the ground, we re objedts “ 2
perceive a black {pot of the apparent fize of that luminary. the eye.
This {pot will by degrees affume a faint green colour, then be-
comes red; and if we pay attention to thefe phenomena, we
fhall find the green and red colours alternate, becoming gra-
~ dually more faint, till they wholly difappear.
If the eye be dire@ted for fome time towards a window, and Inftance of a
then covered by the hand, the bars will firft appear luminous, aa
_ and the fquares dark, and then the contrary, and this will al-
_ ternate till the whole image yradually faints away.
T::efe are termed ocular {pe€&tra, and have been fuppofed Thefe ocular
to depend on the alternate tenfion and relaxation of the: fibres <i Soy
of which the retina are compofed. They refemble the: trem- tate of debility
bling of an over-fatigued mufcle, in which one fet of fibres fatigues
attempts to relieve the exertions of another. Thefe pheno-
mena are moft obvious after the eye has been fatigued by long
continued exertion. They are more readily obferved in the
evening than the morning, and the {peétra of the fetting are
more eafily caught than of the meridian fun,
In certain ftates of bodily debility, whether produced by Spontaneous oc~
the abfence of volition, or by difeafe, they are known f{pon- eh ar Fad
taneoufly to occur. Inthe former ftate, which may be termed reverie, hg
- reverie, when a perfon attends flightly to the impreffions of his
- fenfes, without attempting to regulate them by his will, as
when a perfon looks carelefsly in the fire during twilight, the
infinite
,
230 ON THE PHANTASMS OF NICOLAIL.
infinite variety of fantaftic forms that pafs before the eyes is
familiar to every one. Thefe fancies are however, in fome
meafure, influenced by the train of thinking a perfon is accuf-
Swedenbourg tomed to purfue. Swedenbourg appears to have been per-
perpetually i petually under the influence of this kind of reverie, except
this fate.
when employed in writing an account of what had previoufly
occurred to his mind. Had he, been conftantly occupied in
adtive bodily exertion, perhaps it would have ‘titipgted his
phantafies.
Why dying Picking the bed cloaths, which appears to oceupy the atten-
fer ated, and tion of thofe who are labouring under the debility preceding
imagine they fee death, probably arifes from parts of the retina becoming infen-
demons or dark fible of the impreffion of light, which produces the fenfation
5 ia of fomething dark lying on the bed-cloaths, which they are
defirous to remove, ©The enfeebled mind may not unfre-
quently transform thefe into the figures of demons. The pur-
fuit of the dark fpot formed by the infertion of the optic
nerve, which in that ftate is miftaken for a reality, may alfo
give occafion to this aétion fo frequently obferved among the
dying.
Nicolai evident- - Mr. Nicolai informs us, «that he was in the habit of forming
ly indulged the vivid reprefentations to himfelf not only of whole fcenes of —
ftate of reverie, ; 5 3
comedies, but even of the peculiar dreffes, forms, and com-
plexions of thofe who performed them; that is, he accuftomed
himfelf earneftly to attend to thefe ideal exertions of his own
imagination. In the next place he tells us, that he firft began
' to fee fpecires after having laboured under a nervous fever,
and great trouble of mind. For the melancholy caft of his
earlier vifions, or the appearance of dead bodies, his dejeGted
ftate of mind accounts. That appears however'to have foon _
fubfided. ‘The difeafed ftate of the retina, confequent to his
fever, feems to have continued longer.
The phantafms This fate appears to have been fach as to render him fenfible
were of things of the fpeétra of the things he was in the daily habit of feeing,
before teen, = Fich as men, horfes, lows! &c. for -he does not fay he ever
faw any thing uncommon. What this particular condition of
the retina might confift in, it 1s impoffible to determine. It
may have been a combination of weaknefs with excefs of fen-
fibility. . The fpeétra of the bodies he had feen involuntarily
recurred to his attention, but not with fuch ftrength as to pre~
vent the more forcible impreflion of what was in reality pafling
before
ON THE. PHANTASMS OF NICOLAI,
93h
before him. The notion of hearing the phantoms fpeak I Audible delu-
fhould refer to an affe@tion of the organ of hearing, fimilar to
what took place in the eye. It is evident they were both re~
moved by a flight diminution of the quantity of circulating
blood.
Many ftories of apparitions may, in my~-opinion, be ac-
counted for on fimilar principles. A perfon fixes his eyes in-
tently on the face of an expiring friend illuminated by the light
of a candle, perhaps with the intention of taking a laft fare-
well; foon after, going into the dark, the fpeétrum of this lu-
‘ minous appearance occurs to the fatigued eye, andhe thinks
he perceives the dying man he had juft left, ftanding before
him.
On thefe principles we may venture to correct an error in
the general reprefentation of our juftly popular play of Hamlet.
The ghoft fhould only appear once. This fingle appearance
_ makes fo ftrong an impreffion on the mind of Hamlet, which,
together with an habitual melancholy, was debilitated by care
and vexation, that whenever afterwards he thinks ferioufly on
his father, the {pectrum of the ghoft recurred to his eye, ashe
| _himfelf informs us, when he tells Horatio he fees his father,
and is afked where, he fays, ‘‘ in my mind’s eye.”
- Thefe curfory remaks, Sir, are in fome meafure written to
- evince how much better.it is to attempt at leaft, to account for
phenomena on principles already known, than to hunt fora
new caufe for: every uncommon appearance. But what kind
of philofophifing can we expect from a man, who quotes fuch
eandns as the following, forrules of philofophy? <* That knows
_ ledge derived from experience is merely empirick, and there-
fore not to be depended on.” ‘* That obfervation fhould not
be admitted in theoretical philofophy.” What is theoretical
philofophy? After the exiftence of Bacon, of Newton, and
_ of Locke, who could have expefted to live to fee the whole
thinking part of a nation puzzling themfelves about opinions,
which, if they admit of any defcription, may be charaéterized
as a jumble of the abftraGtions of Arifiotle, with the ideal fyf-
tem of Berkley?
A STUDENT.
fions.
Phantafms of
departed friends»
Correction of
the -reprefenta=
tion of Hamlets
Concluding
remark,
Ill. Exe
232
EXPERIMENTS ON GUM KINO,
iil.
a on the Subftance vulgarly called Gum Kino. By Cir.
VauevuELin *,
Kino not agum. Tur name given to this fubftance is by no means fuited to
Whence it Is
obtained not
known.
' Said to be from
the pau de
fangue of Africa.
Ufed in medi«
cine as a tonic,
Vields an aque-
it; and were it nota common praétice, to give names to things
before we are acquainted with their nature, it would be incon-
ceivable how it fhould have been called a gum, having neither
the phyfical nor chemical properties of one.
Neither have we any accurate knowledge of the tree or of
the country that produces it; but it appears to have been firft
brought to Europe by the Englifh, who made known its medi-
cinal properties, and introduced it into our fhops.
It is called in trade kino or the gum-refin of Gambia. Dr.
Oldfield, who made it known to Fothergill, termed it the true
gum of Senegal. In the Medical Obfervations and Inquiries,
it is faid to be brought from Africa, and the tree that furnithes
it to be called by the natives pau de fangue.
As a medicine it is ufed in the form of boluffes, lozenges,
aqueous infufion, and fpirituous tinéture, as a tonic and aftrin-
ent.
Subjeéted to the aétion of fire, it melts and fwells up con-
ous fluid, an oil, fiderably : yields at firft a clear liquor, which in a few inftants
carbonic acid,
and carbonated
hidrogen.
{ts oile
Its aqueous
product.
Its refiduum.
becomes coloured ; a light and nearly white oil then paffes over,
which in the courfe of the procefs becomes coloured and
heavier than the aqueous produét. A fmall quantity of car- —
bonic acid is likewife formed, with a large quantity of car~ —
bonated hidrogen gas.
The oil produced in this operation unites with cauftic fixed
alkalis, and forms a deep red liquor, that becomes of a dull
green on expofure to the air. |
The aqueous produét is not acid, but has an acrid burning
tafte, owing to a portion of the oil retained in folution; and —
potath feparates from it a large quantity of ammoniac, |
Twenty grammes diftilled with a ftrong heat left eight and
half of a very bulky coal, marked with the colours of the
rainbow; and this coal afforded feventy-two centigrammes of
afhes, confifting chiefly of lime, filex, alumin, and oxide of
iron.
* Abridged from the Azuales de Chimie,
Kino
EXPERIMENTS ON GUM KINO. 2933
Kino is little foluble in cold water, but much more in hot, Its folution in
though a portion of it is infoluble. The folution is flightly YF #!dulous.
acid: alcohol does not precipitate it, but feparates fome red-.
dith flocks; when made with boiling water it grows turbid on
cooling, and depofits a brown red precipitate.
A faturated folution is precipitated by mild alkalis, but Precipitated by
water in fufficient quantity re-diffolves the precipitate. eis —_
Cauftic alkalis likewife precipitate it, but if added in excefs
re-diffolve the precipitate.
Glue diffolved in water forms a very confiderable rofe- and coagulated
coloured coagulum with the folution of kino; and if the quan- by slue-
tities be fuch, that both fubftances are faturated, the fuperna-
tant fluid will be nearly colourlefs.
Though thefe appearances indicate the prefence of tannin Its tannin pre-
in kino, it does not precipitate ferruginous falts black, but of ling hea
a beautiful deep green, fcarcely alterable by expofure to the
air. This property it has in common with the infufions of cin- Contains a prin-
chona and rhubarb; whence it is probable, that thefe three fub- Ng ripe ss
{tances contain a principle of fimilar nature. pain ia
This principle, whatever it be, is very deftruétible: for, if, This principle
alittle oxigenated muriatic acid be poured on the precipitate aie Pees
it forms with iron, this lofes its colour, and does not re-appear
_ on the addition of an alkaline carbonate, which produces only
a red oxide of iron.
The folution of kino copioufly precipitates acetite of lead of Precipitates
a yellowith grey; nitrate of filver of a reddifh yellow, and tar- we bee
trite of antimony of a yellowifh white, but much more copi-
oufly than the infufion of tan or of cinchona; which feems to Ufeful as an an«
indicate, that it would be a better antidote in cafes of perfons tidote.
poifoned by this metallic falt.
Wool and cotton being boiled ina folution of kino, and then Dyes wool and
. dipped in a bath of fulphate of iron, appeared on immerfion cat ic etal
of a bottle-green; but being wafhed and dried, the colour be- ;
came a blackifh brown. It was very durable.
Hot alcohol diffolves kino very well, all but a {mall portion. Diffolves in hot
Water renders the folution a little turbid, but precipitates °° _
nothing.
The portion infoluble in alcohol, nearly a fourth of the whole, Contains a por-
_ has neither the bitternefs nor aftringent tafte of kino; but, on tion of gum.
ihe contrary, is rather mucous and fweet. It eafily diffolves
in
254
This favours the
folution of the
other principle
in watere
|
Water diffolves
5.7.
alcohol moft of
the remainder.
Sulphuric acid
renders it lefs
foluble.
It tans leather.
Neither a gum,
nora gum-refin,
but chiefly a
fpecies of tan
nin,
Dr. Dunean
firft afferted it
to be an extract.
EXPERIMENTS ON GUM KINO.
in hot water, and gives ita fine red colour. It is precipitable:
by alcohol; but neither by glue, nor by any metallie folution.
On burning, it diffufes a fmell refembling that of gum.
I fufpeé the prefence of this fubftance favours the folution
in water of the principle foluble in alcohol; for the latter is
lefs foluble in water when feparated from the former; and, if
the quantity of water neceffary for diffolving the aftringent part
be not employed in the firft inftance, what is left requires a
greater proportion of water.
Four litres of water, ufed at different times, left near
twenty grammes out of ahundred of kino undiffolved. The
refiduum grew foft like a refin in boiling water, and all of it,
except feven decigrammes, was foluble by alcohol, to which
it imparted all the properties before obferved in the aftringent
matter. 4
Sulphuric acid diminifhes the a@tion of water on kino, in-
ftead of increafing it, as it does with refpe@t to the refinous
part of cinchona.
It is capable of being ufed for tanning leather.
From what has been faid it appears, that the greater part
of kino confifts of tannin, and is neither a gum, nor a gum-
refin. But there is a flight difference between it and the tan-
nin of galls and oak bark, which precipitate iron of a blue
black, hile kino precipitates it green, in which it refembles
cinchona and rhubarb. If therefore it were to become plen-
tiful and cheap, it might be employed for all the eek for
which aftringent vegetables are commonly ufed.
Addition.
Mr. Vauquelin is not the firft who difcovered the common
error refpecting kino. In the new Edinburgh Difpenfatory,
Dr. Duncan has entered pretty fully into the fubje&, and afferts
_ it to be in reality an extraét. He adds, that what we have.
Obtained from
the fea- fide
grape,
now in the fhops is not brought from Africa, but chiefly from
Jamaica. In a private letter he informs me, that this is an
extraét of the coccoloba urifera, or fea-fide grape; while the
fineft kino of the fhops, and what from fome circumftances he
fuppofes was the fort analyzed by Vauquelin, is the produ€tof —
and gum-tree of different fpecies of eucalyptus, particularly the refinifera, or
Botany Baye
brown gum tree of Botany Bay, from which country a parcel
was imported fome years ago.
W.N.
IV. Extraa
DR. PRINCE’S AIR-PUMP, 935
IV. \-
LxtraQ of a Letter from Dr. PRINCE, refpecting his
' Aitr-Pwmp.
iy is unneceffary here to enter into the merits.of Dr. Prince’s Dr. Prince's
air-pump, as they were noticed in the 1ft. Vol. of the Philo- eek ae
fophical Journal, 4to. edit. p. 130. The purpofe of his letter the Encyclo-
is to defend himfelf againft the mifreprefentations of the writer P°!4 Britannica,
of the article pneumatics, in the Encyclopedia Britannica;
which he has done in the fupplement to the edition of that
work reprinting in America, where if may be prefumed it
will meet the eye of but few Englith readers, —
The Encyclopedia fays, ‘* great inconveniences were ex-,Charged with
perienced from the ofcillations of the mercury in the gauge. PRN ES 6 ia
As foon as the pifton comes into the eiftern, the air tram the of the mercury
» receiver immediately rufhes into the barrel, and the mercury in the gauges
fhoots up in the gauge, and gets into a ftate of ofcillation.
The fubfequent rife of the pifton will frequently keep time
with the fecond ofcillation, and increafe it. The defcent of
the pifton produces a downward ofcillation, by allowing the
air below it to collapfe ; and by improperly timing the ftrokes,
this ofcillation becomes fo great, as to make the mercury enter
the pump.” :
This, Dr. Prince obferves, is a very fingular account. of This contradi&-
the working of the American air-pump. It feems to be found- pd by kane
ed on experiment, yet it is contradicted by numerous experi-
ments performed with the original pump, and with one on
the fame conftruétion, made by the late Mr. G. Adams in
London. Many fcientific and refpeétable. perfons were
witneffes, that no fuch extraofcillations were produced by it ;
but that the mercury rofe in the gauge in the fame manner as
it did in a double-barrelled pump of the common conftruction
made by Nairne,, Add to this, Mr. Adams, who made the
firft pump in England on this plan, mentions no fueh effect,
either in his letter to the inventor, or in his public account of
it; nor does Mr. Jones, who has fince made pumps on this
plan, and given an account of their exhaufting power, which
he fays, in a letter to Dr, Prince, is fully equal*to that of
Cuthbertfon’s.
To
236
Valves faid to be
put in the pifton
to prevent
downward
efcillation 5
DR. PRINCE’S AIR=PUMP,
To prevent the downward ofcillation, which, Dr. Prince
obferves, could only occur in a fingle-barrelled pump, and
which he obviated by ufing two barrels, the Encyclopedia
fays, “ valves were put into the pifton; but as thefe require
force to open them, the addition feemed rather to increafe
the evil, by rendering the ofcillation more fimultaneous with
the ordinary rate of working.” If, replies the Doétor, fuch an
evil were produced by the defcent of the pifton, it is dif
ficult to conceive, how putting valves into the pifton could
but valves could have increafed it. They could not increafe the evil, unlefs
not increafe its
refiftance.
Said to be dif-
ficult of execu-
tions
but lefs fo than
ethers.
Subfeauent im-
rovements.
they increafed the refiftance to the air under the pifton. But
it muft be a ftrange affertion, that a pifton with a valve in it
will give more refiftance to the air than a folzd pifton.
Another objection is: “it appears of very difficult execu-
tion. It has many long, flender, and crooked paflages, which
muft be drilled through broad plates of brafs, fome of them
appearing {carcely pra@ticable. It is rare to find plates and
other pieces of brafs without air-holes, which it would be
difficult to find out and clofe, &c. Now the fact is, there is
not fo much pipe and duét-work in the American air-pump,
by more than one half, as in Mr, Nairne’s improved pump of
Smeaton, againft which no fuch objeétion is brought. There
can be no reafon to prefume the brafs work would be more
defective, unlefs it were more complex in its form. And it is
obvioufly far fuperior in point of fimplicity to Cuthbertfon’s,
which the Encyclopedia confiders as “ the moft perfe&t that
has yet appeared.”
After thefe flri€tures on the Encyclopedia Britannica,
Dr. Prince gives an account of the improvements he has
made on his former attempt.
‘ The following improvements have been made in the
American air-pump, by the inventor, to render it more fimple
and convenient. It has been obferved above, that in all air-
pumps, made to condenfe as well as exhauft by the fame
barrels and winch, there muft be additional pipes, duéts and
cocks to command and regulate the operations: But this is
not the beft method of conftruéting the inftrument for ex-
haufting and condenting experiments: for a great ftrain is
brought upon the rackwork of the pump when feveral atmof-
pheres are throw into the receiver: and the pump may be
made with lefs trouble and expenfe by fixing a common con-
denfing
DR. PRINCE’S AIR-PUMP. $ 937
denfing fyringe toit, in the following manner. Let.a ftraight Bef made to
pipe be fixed to the cifterns, and pafs horizontally to the re- mi ae
ceiver-plate, as in the common table air-pump. At a con-fyringe. |
venient diftance from the barrels this pipe muft be fwelled out
fo as to admit the key of a ftop-cock. The key of this cock Stop-cock for
muft be pierced quite through in the direétion of its handle; a
and half way through, at a right angle to meet the other hole.
A {mall pin muft be fixed in the handle, on that fide which
correfponds with the fhort hole. A: hole muft be made in the
fide of the pipe to correfpond occafionally with the holes in
the key. This cock is more fimple than the one in the
original pump, and will regulate the exhaufting and.conden-
fing experiments. To fet the cock for exhaufling the receiver,
bring the handle of the key parallel with the pipe, with the
folid part of the key againft the hole in the fide of the'pipe;
then will the communication be opened between the barrels
and receiver, and the receiver may be exhaufted. To reftore
the equilibrium, or let the air into the receiver, fet the handle
of the key at right angles with the pipe, and let its proje@ting
pin point to the receiver; then will the communication be
opened between the atmofphere and receiver, through the
hole in the fide of the pipe and the cock. In this fituation
the folid part of the key will clofe the paflage in the pipe lead-
ing to the barrels. Ifa condenfer, having a valve at its end, Mode of con-
be now attached to the fide of the pipe, oppofite the hole, the “fs.
air may be forced into the receiver through the cock without
entering the barrels. The fwelled part of the pipe, in which
the key is inferted, fhould be fo made as that the condenfer
may be ferewed on or off, at pleafure. The equilibrium may
be reftored in the receiver, either by unfcrewing the con-
denfer a little, or by letting the air out through the barrels,
* Inthis conftru€tion, the pipe ftanding between the barrels The pump thus
in the original pump, and the drilled paffages in the horizon- ei 5 aa
tal piece conneéting this pipe with the regulattng cock, are |
unneceflary. The pump is rendered more fimple, and every
difficulty of execution on account of crooked paffages, &c.
removed. This alteration in the American air-pump was con-
trived by its inventor, and a table-pump made on this plan,
for him, by the late Mr. G. Adams, betore the laft edition of
the Encyclopedia was printed,
« Another
238 DR. PRINCE’S AIR-PUMP.
Alteration in ‘ Another alteration, fince made, is in the fituation of the
the valve-pump valve.pump: the laft mentioned pump not having one fixed
to it. In all air-pumps having the tops of the barrels clofed
with plates and collars of leather, as in Nairne’s, Cuthbert-
fon’s, and the American pump (as now altered by removing
the middle pipe,) it is neceflary to connegt oil boxes with the
top-plates to receive the oil which is thrown out of the barrels
in working the pamp. Cuthbertfon’s pump has two, one to
each barrel. By removing the pipe from between the barrels,
in the Americen pump, a fmall barrel is ferewed in its place
to the crofs-piece, which conneéts the top-plates covering the
Barrel to anfwer valves. The barrel anfwers the purpofe of an oil-box in
the purpofe of an : . : ‘
il-box, and alfo Common exhauttions. When greater vacuums are wanted in
a valve-pump, the receiver, this barrel anfwers alfo for a valve-pump. On
the top of the crofs-piece is {erewed a collar of leathers con-
taining a pifton and its rod, to work occafionally in the barrel
below. At the lower end of the barrel is a valve covered with
acap: by unfcrewing the cap, and pafling down the pifton,
all the oil in the barrel is expelled through the valve; and
afterwards the barrel, and the fpace above the valves on the
top-plates of the great barrels, are exhaufied of air, by work-
ing this {mall pump. The fmall pifton when drawn up to its
coliar of leathers is above the holes:in the crofs-piece leading
from the valves. When the fmall barrel is ufed only as an oil-
box, the collar of leathers, with the pifton, is removed, and
a button, with a thort pipe in it, ferewed in its place to give
vent to the air when expelled from the barrels: In this valve-
This noaddi- pump there is not fo much work as in Cuthbertfon’s two oil- ~~
tional expencee boxes; nor is it an additional expence; for the fyringe, which
is ufed with the lead weight in the receiver, is made to fcrew
to the crofs-piece for this purpofe; the weight being taken
off, and a cap ferewed on over the valve, when ufed as an
oil-box. In the collars of leathers, on the tops of the barrels,
are put two {mall flat boxes, below one or two rings of the
The oil neither leathers, the pifton rods paffing through them. Thefe boxes
thickened by —_ gontain the oil to keep the leathers moift, and air-tight. In
evaporation, nor p i ; oe . re P;
carried off from this fituation the oil is not thickened by evaporation, nor carried
the leathers. up from off the leathers, when the pifton rifes, as in Nairne’s
pump, and the leathers are better fupplied than by the dirty
oil paffing through the pump and returned to the collars by
Cuthbertfon’s crooked pipes. The American air-pump, made
jn this manner, is the fimpleft form of any pump of equal power.’
M em cir
+
ON THE TIDES. 939
V.
Memoir on the Tides, By Cit. Laritace *,
Tue object of this paper is to compare the high tides ob-
_ferved on the 23d of March laft, with the refults indicated by
the theory of univerfal gravitation.
At this period the moon was new,. and in her perigeum, New moon, in
Thefe circumftances, joined to thofe of an equinoétial ; yZygy, Ea nnaeeee.
are the moft favourable to high tides: and if at fuch atime the zygy, mot fa
~ a@tion of the winds fhould combine with thefe regular caufes, vourable to high
inundations may follow, againft which it is prudent to ufe ie
precautions, It is with this view that the board of longitude
publifhes in the Connoigunce des Tems every year, a table of
the higheft tides that follow every new and full moon.
_ To know the real height of the tide produced by the ation Height of tide
of the fun and moon, and diftinguifh it from that which is ow- ve difference
: . é SR. i etween ebb and
ing to the temporary aétion of the wind, it is not fufficient to flood. Li
obferve the abfolute height at flood, but the corref{pondent ebb
muft be obferved likewife, and the difference between them
gives the total height of the tide. We can eafily conceive, Wind a@s
, that the aGtion of the wind muft add to the height of the water, ©dl!y om both.,
both at ebb and flood, nearly in an equal degree. This con-
fideration is indifpenfable, for without it all we can deduce
from obfervation is the fum of the combined effeéts, without
being able to feparate and refer them to their real caufes.
The tides of the 23d of March were obferved at Breft by Tide of 234 of
Cit. Rochon and Mingon. The total height was 23 feet cape
four inches, the greateft ever obferved. That which came
neareft to it, was as far back as the 23d of September 1714, Sept. 23, 1714.
when the moon was fall, in her perigeum, and almoft without
declination, as well as the fun. Its total height was 22 feet
11 inches. . |
_ According to the theory given in the fourth book of La Mé- Theory in La
: Z re : Mecanique Celefie
canique Célefte, the greateft difference between high and low eS a
‘water in the preceding fyzygies, is 22 feet 10 inches, which fervation.
_ differs very little from the obfervations: But in that book it is
remarked, that the local circumftances of every harbour may
eccafion the relation of the action of the {un and moon on the
- * National Inftitute of France, IV.
? phenomena
240
Time of high-
water at Breft
has net varied in
near a century.
Series of obfer-
vations on the
tides propofed.
Maenefia with
carbonate gene-
rally in fmall
quantity in
ftones.
Charaéters of
the ftone of
Caftclla Monte.
NATIVE CARBONATE OF MAGNESIA.
phenomena of the tides to vary. A comparifon of the obfer-
vations made at Breft, has made known to Cit. Laplace, that
circumftances there increafe the a€tion of the moon one-fixth ;
and with this modification the refult of the theory isa mean be-
tween thofe given by obfervation.
The high tide of the 15th of September 1715, in the morn-
ing, and that of the 23d of March laft, in the evening, were
nearly equidiftant from the fyzygy, which fhould give the fame
hour for the tides, if the local circumftances of the harbour have ,
not varied in the interval of nearly a century. The firft was
obferved at. half after four in the morning, true time; the
fecond, at 29 minutes after four in the evening: whence it
appears, that the time of the tides at Breft has not varied in that »
period,
Cit. Laplace has propofed to the firft clafs of the Inflitute, to
folicit government to direé a feries of obfervations to be made
on the tides in the different harbours of France; and to appoint
a committee to draw up a fingle body of inftruétions for the
beft mode of making thefe obfervations. _ Both propofals were
adopted.
The whole of the paper, of which an abftraé is here given,
will be printed in the Connoigunce des Tems.
VIL
Abjiract of a Paper by Cit. Guyton-Morveau, entitled an
Examination of a native Carbonate of Magnefia*.
‘LT Houcn magnefia is a conftituent part of many flones,
it enters into them but in fmall quantity, with few exceptions,
Native carbonate of magnefia occurs ftill more rarely in any
confiderable proportion, Citizen Guyton, however, fearch-
ing for a clay pofleffed of the hygrometric property in the
higheft degree, lately found a very large proportion of native
carbonate of magnefia in a ftone in the vicinity of Caftella-
Monte, which is there confidered as a clay very rich in
alumine.
This flone is as compact as the hardeft chalk, in an amor-
phous mafs, and as white as cerufe. It does not fenfibly ad
here to the tongue, and has no argillaceous {mell. Water aéts |
* Bulletin des Sciences, No. 75.
very
NATIVE CARBONATE OF MAGNESIA. 94}
very flightly on it; it is not reducible to a folid pafte; yet on
drying it appears to agglutinate, and contraét a little its di-
menfions. Its fpecific gravity, when all the bubbles of air it
contains have efcaped, is 2.612. In the fire it loft 0.585 of
its weight, and became fufficiently hard.to fcratch Bohemian
glafs lightly. Five grammes, being diffolved in nitric acid,
gave out a large quantity of gas, by which the weight was di-
minifhed 230 centigrammes. .
Concentrated fulphuric acid, poured on the ftone reduced Effervefces with
to powder, occafioned a violent effervefcence on the addition pupinscen
of water. Without this addition the effeét was not perceptible.
By this treatment a falt cryftallized in fmall neédles was ob- and yields ful-
tained, which difplayed all the properties of fulphate of mags a 5 ay aa
nefia.
This falt was precipitated by potafh, and the precipitate,
when dried, weighed 131.5 centigrammes.
The portion not diffolved by fulphuric acid was pure filex, Contains filex.
and weighed 71.2 centigrammes.
~ Pruffiat of foda gave the folutions a flight greenith tinge, but
nothing capable of being weighed was depofited.
_ This ftone therefore contains, Its analy fis.
Magnefia ' “ “ 26.3
Silex - - = 14.2
Carbonic acid a: « 46
Water “ - - 12
Iron * = - 8)
Lofs - . < 1.5
100.0 6
Cit. Guyton obferves, that the difference between the pro- How it differs }
portions of the conftituent fubftances of this ftone, and thofe of fowstheaiee F
the artificial carbonate of magnefia, arifes no doubt from the
circumftances in which thefe falts have been produced; and
the other chara¢teriftics, that diftinguifh them, may be occa-
fioned by the prefence of the other fubftances found with the
carbonate ef magnefia in the ftone of Caftella-Monte.
Vou. VIl.—Dercremeer, 1803. R Curious
P42 PARTICULARS OF SOUTH AMERIC4,
VIL.
Curious Particulars réfpedting the Mountains ‘and .Volcanos,
and the Efe of the late Earthquakes in South America, with
Remarks on the Language and Science of the Natives, «and
other Subjects. By M. A. Von Hompoupr *
Three branches Wer arrived at Quito, by crofling the fnows of Quridien
ef the Andess aq Tolima, for as the cordillera of the ‘Andes forms three fes
parate branches, and at Santa Fe de Bogoto, we were on th¢
eafternmoft, it was neceflary for us to’ pafs the loftieft, in
‘order to reach the coaft of the Pacific ocean. We travelled
oh foot, and {pent feventeen days in thefe deferts, in which
are tobe found no traces of their ever having been inha-
Huts madeof hited, We flept in huts made of the leaves of “the heliconia,
the leaves of he- A
edna: which we carried with us for the purpofe. Defcending the
The Andes -Andes to the weft, there are marfles, in which you fink u
prog ee to the knees. The latter part of the time we were deluged
the weft.
with rain; our boots rotted’ on our legs; and we arrived
barefoot at Carthago, but enriched with a fine colleétion of
new plants, of which I havea great number of drawings.
Mines of Platina
i Choca. sf . : ‘ .
in mount ™ hoc eroffing the beautiful vale of the river Cauca, and haying con-
‘ftantly.at ‘one fide the mountain of Choca, in which are the
mines of Platina.
Bafaltic moun- We ftaid during the month of November 1801, at Po-
tainse payan, vifiting sa Bafaltic mountains of. Julufuito ; \ the
motiths of the voleano, of Purace, which, evolve, with a
dreadful noife, vapours of hydrofulphurated water ;' and the
Columnar por- porphyritic.granites of Pifche; which form -columns. of five,
phyritic gra- fix ot feven fides, fimilarito thofe I remember I faw in. the
ae Euganean mountains in Italy, which Strange has deferibed. |
Voleano of
Purace.
Paramospiercing Jn travelling from ‘Popayan to Quito, we had to crofs the |
cold and defti-
tute of vegera- P2AMOS of Pafto, and this in the rainy feafon. Every place Db
tions in the Andes, where, at the height of 3500 or 4000 yards,
vegetation ceafes, and the cold penetrates to the very mar-
row of your bones, is called a paramo. To avoid the heats —
* Abridged from the Magazin Encylopédique.
From Carthago we went to Popayan, by way of Buga, —
rt
f PARTICULARS OF SOUTH AMERICA. , 243
of the valley of Patia, where, in a fingle night, a fever may
be caught, that will laft three or four months, we paffed the
fummit of the Cordillera, traverfing frightful precipices.
_ We fpent our Chriftmas at Pafto, a lit(le town at the foot Town of Pattas
ofa tremendous volcano, where we were entertained with
great hofpitality. The roads leading to and from it are the
moft fhocking in the world. Thick forefts, between marthes,
in which the mules fink up to their bellies; and gullies fo
deep and narrow, that we feemed entering the galleries of a
mine.
The whole province of Pafto, including the envirors of The provinee a
Guachucal and Tuqueres, is a frozen plain, nearly beyond the ee
point where vegetation can fubfift, and furrounded by vol-
.canos and fips. pits; continually emitting volumes of :
{moke. The wretched inhabitants of thefe Weer have no The people lise
food but potatoes : and if thefe fail, as they did laft year, they 0" Potatoes, _
go to the mountains to eat the ftem of a little tree, called
achupalla (pourretia pitcarnia) ; but the bears of the Andes, and the ftems of
as they too feed on it, often difpute it with them. On the Sage Pitr
horth of the volcano of Pa fto, I difcovered, in the little In.
dian village of Voifaco, 1900 yards above the level of the
fea, a red porphyry, with bafe of argil, enclofing vitreous Rea porphyry
- feld{par, and hornblende, that has all the properties of the With diftinet
Terpentine of the Fichtelyebirge.. This porphyry has very oe
diftinétly marked poles, but no attractive power. Near the
‘own of Ibarra, we nearly efcaped being drowned by a very
udden fwell of the water, coshre with fhocks of an
earthquake.
We reached Quito on the 6th of January 1g02. It is aQuito.
handfome city ; but the fky is commonly clouded and gloomy.
The neighbouring mountains exhibit little verdure, and the
_ cold is very confiderable. The great earthquake on the 4th Earthquake of
of February 1797, which changed the face of the. whole ‘797°
province, and in one inftant deftroyed thirty-five or. forty
thoufand perfons, has fo altered the temperature of the air, @ltered the
that the thermometer i is How commonly 412 to 54°; and fel- uate greatly,
dom rifes to 68° or 70°, whereas Bouguer obferved it con-
ftantly at 66° or 68°. Since this cataftrophe, earthquakes
are continually recurring ; and fuch fhocks! it is probable,
that all the higher ground is one vaft volcano. What are The heights one
called the mountains of Cotopoxi and Pichincha, are but little va volcanos
R 2 fummits,
44. PARTICULARS OF VoLcANOS AND EARTHQUAKES.
fummits, the craters of hick, form different conduits termi-
nating in the famecavity, The earthquake of 1797, afforded
a melancholy proof of this; for the ground then opened every
People of Quito, where, and vomited forth Yulphur, water, &c. Notwith-
ftanding the dangers and horrors that furround them, the
people ae Quito are gay, lively, and fociable, and in no
place did i ever fee a more decided and general tafte for plea-
fure, luxury, and amufement. Thus man accuftoms himfelf
to fleep tranquilly on the brink of a precipice.
P ichiueha, I was twice at the mouth of the crater of Pichincha, the
mountain that overlooks the city of Quito. I know of no one
but Condamine, that ever reached it before; and he was
without inftruments, and could not ftay above a quarter of an
hour, on account of the extreme cold. I was more fuccefsful.
Its crater. From the edge of the crater rife three peaks, which are free
from fnow, as it is continually melted by the afcending vapour.
At the fummit of one of thefe I found a rock, that projeéted
over the precipice, and hence I made my obfervations. This
rock was about twelve feet long, by fix broad, and ftrongly
' agitated by the frequent fhocks, of which we counted eighteen
in lefs than half an hour. We lay on our bellies, the better
to examine the bottom of the crater. The mouth of the
volcano forms a circular hole, near a league in circumference, _
the perpendicular edges of which are covered with fnow on
the top. The infide is of a deep black ; but the, abyfs is fo
Several thoun- “Walt, that the fummits of feveral mountains may be diftin-
tains within it. guifhed in it. Their tops feemed to be fix hundred yards
below us, judge then where their bafes muft be. I have no
doubt but the bottom of the crater is ona level with the city
of Quito. Condamine found it extin@, and even covered
with fnow; but we had to report the unpleafant news, that
Itsdiameter it was burning. On my fecond vifit, being better furnifhed
1600 yards; With inftruments, I found the diameter of the crater to be
height 52808 1600 yards, whereas that of Vefuvius i is ane 670. "The height
of the mountain is 5280 yards.
Volcano of Ans When we vifited the volcano of Antifana, the weather
ae 59'5 was fo favourable, that we reached the height of 5915 yards.
ane ar inthis lofty region, the barometer funk to 14 inches 7 lines,
15.6 inches. [15.6 Eng.] and the tenuity of the air occafioned the blood —
Hemoirhages to iffue from our ‘lips, gums, and even eyes: we felt ex- |
Proaghton, tremely feeble, and one of our company fainted away, The
f alt
PARTICULARS OF VOLCANOS AND EARTHQUAKES. 245
air brought from the loftieft point we vifited, gave on Air 0.218 of
being analyfed 0.218 of oxigen gas, and 0.008 ‘of carbonic °!8™
acid.
We vifited Cotopoxi, but could not reach the mouth of Cotopoxi not
the crater. The affertion, that this mountain was diminifhed Cuabeaneds
in height by the earthquake of 1797, is a miftake. 797
In June we proceeded to meafure Chimboraco and Tungu-
ragua, and take a plan of all the country affected by the
grand cataftrophe of 1797. We approached within about 500
yards of the fummit of Chimboraco, our afcent being faci-
litated by a line of volcanic rocks bare of {now. The height Air at 6465
we reached was 6465 yards; and we were prevented from a
5 0.20 of oxigen.
afcending farther by a chafm too deep to crofs. We felt the
fame inconveniences as on Antifana; and were unwell for
two or three days after. The air at this height contained
0.20 of oxigen. The trigonometrical meafurement I took
of the mountain at two different times, and I can place fome Chimboraco
confidence in my operations, gave me for its height 6970 eat yards
yards, a hundred more than Condamine afligns it. The
whole of this huge mafs, as of all the high mountains of the Confifts of por-
Andes, is not granite, but porphyry, from the foot to the Phyry-
fummit, and there the porphyry is 4050 yards thick.
Chimboraco is probably a volcanic mountain, for the track Chimboraco a
by which we afcended, confifts of a burnt and feorified rock prem
mixed with pumice-ftone, refembling all the ftreams of lava
in this country, and ran higher up the mountain than we
could climb. The fummit therefore is in all likelihood the
crater of an extinét volcano.
The mountain of Tunguragua has diminifhed in height fince Tunguragua
the earthquake of 1797. Bouguer affigns it 5589 yards, Lp hneges ais
found it but 5399, fo that it muft have loft 190 yards; and now 5399
indeed the people in the vicinity fay,. that they have feen its yards.
fummit crumble away before their eyes,
During our ftay at Riobancha, we accidentally made a
very curious difcovery. The ftate of the province of Quito,
previous to its conqueft by the Inca Tupaynpangi, in 1470, is
‘wholly unknown: but the king of the Indians, Leandro Indian manu-
. Zapla, who refides at Lican, and has a mind extraordinarily on
‘cultivated for an Indian, poffeffes manufcripts compofed by “i
“one of his anceftors, in the fixteenth century, which contains
i the hiftory of that api vt se are written in the Parugay
tongue,
946 eR tre are RESPECTING SOUTH AMERICA,
iongue, which was formerly general in Quito, but is now
Joft, having been fupplanted by the Inca or Anichna. ‘Fortu-
nately agers of Zapla’s anceftors amufed himfelf by ‘tranf-
lating thefe memoirs into Spanifh, We have obtained from
them valuable information, particularly in the memorable
Nevado del period of the eruption of Nevado del Atlas, which muft
pees have’ been the higheft mountain in the world, loftier than
tain in the Chimboraco, and called by the Indians Capa-urcu, or chief of
world. mountains. Thefe manufcripts, the traditions I colleéted at
Hieroglyphics. Parima, and the hieroglyphics I faw in the defert of Cafi-
duiare, where fcarcely a veftige of a human being is now ‘to
be feen, added to what Gatgite has faid of the emigration
of the Mexicans toward the une have fuggefted to me ideas
refpeéting the origin of this people, which I fhall purfue
when I have Hs
American ane J have likewife paid much attention to the ftudy of the
uages net poor» American languages, and found what Condamine has faid
Catibee. —«oOf'- their poverty to be extremely falfe. The Caribbee is rich,
Vs beautiful, energetic, and’ polifhed: it is not deftitute of ex-
prefions for abftraét ideds; and it has numerical terms fuffi-
Inca. cient for any poffible, combination of figures. The Inca is
) particularly rich in delicacy and variety of expreffion. The
Ancient fcience. priefts knew how to draw a meridian line, and obferve the
folftices: they had reduced the lunar to a: folar year by in-
tercalations: and the favages even at Erevato, in thé interior
of Parima, ‘believe the moon to be inhabited, and know, from
the’ traditions of their anceftors, that its light i is derived’ from
the fun. vie .
Crocodile ine At Monpox I made fome very curious experiments on the
creafes ait by refpiration of the crocodile, having procured forty or fifty
pee young ones. Inftead of diminifhing the quantity of the air
in’ which it refpires like other animals, the crocodile in-
Air 274 oxigen, creafes it. A crocodile placed in 1000 parts of atmofpheriec ;
15 carbonic air, confifting of 274 oxigén, 15 carbonic acid, and 711
igi a: ahaa azot, sain it in an hour. and forty-three minutes, by the
addition of i124 parts. The carbonic acid had received an
augmentation of 64 parts: the oxigen had been diminifhed
167; bul, as 46 are contained in the carbonie acid pro-
duced, the crocodile had appropriated to itfelf only ¥21
parts, a {mall quantity confidering the colour of its blood :
and 227 pac of azot, or omer gaffes,,on which acidifiable
‘ pater
MEASURING SCREW. DAZ
bafes had no a€tion, were produced. For the analyiis I
ufed lime water and nitrous gas, prepared with great care.
Near Santa Fee, at an elevation of 2890 yards, are found Large foffil
an immenfe number of foffil bones of elephants, both of the Ree iol pe
African fpecies and of the carnivorous kind, difcovered in and nearly from
North America. I have fince received others from a part lpr rages]
the Andes, about the latitude of 2° from Quito, and from other. °° *
Chili: fo that thefe animals muft have exifted from Patagonia
to the Ohio.
VIII.
Method of meafuring any Aliquot Part of an Inch by a Screw,
which gives no fuch Part in its Turn; and Obfervation on an
Error of Edwards in placing the Eye Stop of refléQing Telee
fcopes. Ina Letier from Mr. J.C. Hornsprower.
To Mr. NICHOLSON,
DEAR Sir,
Bermnc on a vifit about fifteen years ago in the confines of Conftruction of
the prineipality, (a region {ciepce never yet explored) I was in ais
want of a reticulated fquare to be placed in the focus of the
eye glafs of an optical inftrument, and by the difappointwent
ufually attending jobs of this kind when done at a diftance, I
refolved on accomplifhing it myfelf, though I forefaw it would
‘be a difficult undertaking, efpecially as I am but an indifferent
workman even with the beft tools, and with fuch as lay before
me, I could not anticipate much pleafure in my tafk.
The firft thing which occurred to me was, the conftruétion A ferew was
of the old fafhiqned micrometer, and I found a tap which, pro- ™#e by tap~
mifed well for the purpofe; but unfortunately it had no deter-” *
minate number of threads; but neverthelefs I was refolved to
proceed, and by this tap J cut a pair of dies, and by them I
cut a ferew ona piece of large brafs wire, which being more
homogenous than fteel in general, had a better chance of the
“aecuracy my inftrument required, however I fet the nut in a
jimbal, and on trying the fcrew, I found it had 26,6 threads in
¥ an inch, and as I wanted tenths of an inch, I muft neceflarily
rovide means to correé the excefs or defeét in the fcrew,
which I did thus;
et eb \ : The
248 MEASURING SCREW; &c.
This was fitted = The fcrew had a collar, which I could draw together fo as
up with a mi-
crometer plate, 0 hold it faft, and another collar, on which I put the di vided
and hadaclip, plate, and after that an index firmly fixed on thefcrew. The
ae plate alfo having liberty to turn on its collar, I could faften it
held faft while independent of the ferew, by having two thumb ferews op-
ae wa pofite each other, bearing on the periphery of the plate, fo
that I could turn the fcrew only, or turn the plate only, or
turn them all together. l
The fcrewwas “The operation was as follows: Having laid the frame I had
turned, the tg divide on the board, to which this apparatus was connected,
quantity anfwer- é F
ing to 0.1 inch; I brought the index to 0 on the plate, and made it (the plate)
then clipped faft faft, then turned the index two revolutions and ,66 of a revo-
and the micro- i A =the ‘
meter fet'to zero: Iution: This gave mea divifion of ,J inch. I then faftened
the ferew was the {crew by bringing the collar to bind upon it; liberated the
bla aN plate, and turned it until O on the divifions came to the index.
then clipped, The plate was then faftened, and the {crew fet free and turned
i a 2,66 revolutions as before., The ferew was then again faftened
fcrew then fet and the plate fet free, and O brought to the index as before,
i movedy after which the plate was faftened, and the ferew fet free and
a turned, &c. With a little addition of apparatus tomake the
faftenings and loofenings inftantaneous; this method may be
ufed to much advantage when amore elaborate or {cientific in-
ftrument cannot be obtained.
I forgot in our converfation on the fubject of refleéting tele-
fcopes, to bring to your mind a falfe calculation of Mr, Ed-
wards’s in his dire@tions for making fpecula for refle@ting tele-
- fcopes, publifhed in the nautical almanack fome years fince.
Mr. Edwards Concerning the place of the eye ftop, his words are ‘It is
ST Eotase abfolutely neceflary for perfe& vifion that the eye fhould be
fieéting tele- | applied to a fmall hole of a certain dimenfion, placed exactly
apie oo in the focus of the fingle eye-glafs, if the eye-piece confift of
of the eye glafs, one glafs only, or elfe in the compound focus of the glaffes ;
ae if it is conftruéted with two, as is moft commonly praétifed ;”
and afterwards fays, ‘‘ Let the diftance of the eye-hole from
the eye-glafs, if it is a fingle one, be put as near as can be
attained by meafure, equal to the focal diftance of the eye-
glafs, &c.”
Butit ought not = Surely Mr. Edwards muft have taken this on.a bare fuppo-
a yanlleliaes, fition, without ever enquiring why. When we {peak of the
but of rays from focus of a lens, it is generally underftood to mean the focus
the vortex of the "
Bsfice fpcers- of parallel rays, but the focus of parallel rays does not deter
‘lum, mine
ELASTIC FORCE AND EMISSION OF STEAM. 249
"mine the place of the eye ftop, but a focus, where the image
of the {mall {peculum is formed, and this will be more or lefs
accordingly as the diftance between the lens and the fpeculum ‘
is lefs or more. For inftance, take a lens of 1,5 inch focus,
which would fuit a fpeculum of 9 inches focus, and the dif-
tance of the fmall {peculum will be about 14 inches from the
eye glafs. Then 14x1,5
L4—1,5
of the eye ftop, or in other words, the focus of rays proceed-
ing from an objeét placed 14 inches beyond the lens, almofi
two inches farther than the folar focus.
Iam,
Dear Sir,
Your moft obedient Servani,
J.C. HORNBLOWER.
= 1,68 will be the true diftance
are
IX.
Account of anew Apparatus conftruéted for the Purpofe of mea-
Juring the Elaftic Force, and regulating the Emiffion of Steam
from the Boiler in which it ts generated. Communicated by the
Inventor, Mr. ARTHUR Woo tr, Engineer.
Plate. XIV. exhibits a meafured feétion of the felf-acting Self a@ing ana
and regulating fteam valve. A A reprefents the upper part of spre he Ream
the boiler, having its mouth or neck cylindrical. and clofed by
a well-fitted, but eafily moving valve plug BB CC, which is
in faét a metallic tube, open at bottom and clofed above, by a
cap-piece BB, «that by its chamfered rim or projeéting part
‘affords the accurate valve-clofure when down. The interior
parallel lines at D fliew the place where a long perioration is
made through the fide of the cylindrical part of the valve plug
from its cap, nearly down to the bottom; which perforation
affords a paflage for the fteam, increafing in magnitude as the
elaftic force caufes the valve to rife. E is the fide paflage for
“conveying the fteam to its place of operation. F is the rod or
tail of the valve pafling through a ftuffing box above, and at-
‘tached by a chain to the feétor G, and by its means moving
the lever that carries the ball H.
The
250 JOURNEY TO THE SUMMIT OF MONT-PERDU.
The above conftitutes the whole of this fimple and effecs
tual contrivance, and its mode of operation fcarcely needs
to be deforibed. Asthe fteam becomes ftronger it raifes the
valve, and efcapes through D, and raifes the weight H
higher the more the, preflure within exceeds that of the
working fteam in the upper fpace F E,
xX.
fourney to the Symmit of Mont-Perdu, By Cit. RAMOND™*®,
Sauffure’s tra- OT HE an excellent obfervations made by thecelebrated Sauf-
vels in the Alps fure in the Alps, trayerfing that grand affemblage of mountains in
highly ufeful to
eAploege all dire@tions, have contributed more effectually to the advance-
ment of geology, than all the hy pothefes that have been formed,
Ramond’s in the Cit. Ramond is rendering a fimilar fervice to the feience, by
Pyrenees. his repeated journies in the Pyrenees; and his adventurous re-
fearches will foon bring us acquainted with a great part of that
ig ihe firu€ure of which is fo different from that of the
Alps. Ina work publifhed two years ago, he defcribed the
batis of Mont-Perdu: he had even approached its fummit, and
had obferved that this mountain, the loftieft of the Pyrenees,
was calcareous, and contained fhells and other organized
bodies, ima foffil flate, at an elevali ion of about 3600 metres,
Bethe’ the In the journey he made in Augutt 1802, he reached the
fummit of Mont faummit of the mountain by pafling the Col de Fanlo, or Nifcle.
Saha Arata 21 this road he conftantly: found Pa a of compact carbonated
of carbonated lime in a pofition nearly vertical. They include ftrata of cal-
rica of Careous fandftone, and thefe {trata fometimes cover the falient
calcareous fand- angles of the vertical ftrata, nearly in a horizontal direion.
ftone. This calcareous fione falls off fpontaneoufly i in little irregular
fragments: on the flighteft friction it emits a naufeous fetid
—fmell. Some of the ftrata of this {tone contain nodules of flint;
others fuch confiderable maffes of camerines, that the ftone ap-
Summit a fetid pears entirely compofed of them. The fummit is formed of a.
Himeftone. fetid lime-flone, contaminated with quartz, and containing a
little iron, and =2, of carbon, without alumine. Cit. Ramond
found no fragments of fhells: but this fone being of a fimilar
* Bulletin des Sciences.
kind
JOURNEY TO THE SUMMIT OF MONT-PERDU. 251
kind ‘to -the neighbouring ftrata, in which they occur, he is
inclined to believe, that he fhould difcover fome on a more
fedulous refearch. The elevation of this fummit is the fame as Its highs 3727
that of the Col du Géant in the Alps, or 3426 metres. Fandss
From this, the loftieft point of the Pyrenean chain, Cit. Parallel lines of
Ramond could more eafily obferve the general form of the ie ee Se
rench fide
whole. Looking toward France, the chain is broad, an
formed of feveral parallel lines of mountains, in the midft of
which are feen the lines of granite ‘and gneifs, of which the Granite and
peak of Bagneres is a part. Thefe are more diftinguifhable eke ae
by their fumnatits bzing rugged with afperities, than for their
elevation. Thefe eo imperceptibly diminifh in height till
they reach the plain, which is too far diftant to be feen. To On the Spanifh
the fouth the appearance is very different. The whole declines ake lofty pres
fuddenly, and'at once. It is a precipice of ten or eleven hun-
dred metres, the bottom of which is the fummit of the higheft
mountains of this part of Spain. Not one of them, however,
has 2500 metres abfolute height, and they foon fink into low
founded hills, beyond which is the vaft profpect of the plains
of Arragon.
From the fummit of Mont-Perdu, on the Spanifh fide, is Beneath this a
feen a vaft flat of limeftone, the furface of which, from that flat of limettoney
elevation, appears almoft fmooth. This flat is interfected by interfeétea by
four or five vaft chafms with perpendicular fides, the angles vat chatms,
and finuofities of which correfpond to each other with aftonith-
“ing exatnefs. Thefe broad and deep chafms diverge from the
bafe of the peak, and their bottoms are covered with thick
woods. There is no way of entering them but at their mouths.
Cit. Ramond proceeded by the way of Val de Broto, and en-
tered that called by the natives Val d’Ordefa, It is a deep Val a’Ordefa,
valley, uninhabited, and bordered ‘by fleep walls about 896
metrés high. Thefe you can afcend only in few places, and
with the greateft difficulty. You then reach the flat, The
ftrata that form it, and in which thefe vaft chafms have been
opened, are horizontal, or very little inclined. They confift The trata red
of red fandftone of ancient formation, pudding-ftone, and com- {nditone, pud-
paét limeftone. All thefe flones are difpofed to break off in he Eioaes 3
a dire@tion perpendicular to their beds, and Cit. Ramond
afcribes this difpofition to the quartz they contain, He thinks
that ‘the chafms, opened at firft by fome unknown caufe, have
been enlarged by the crumbling of their fides in this manner.
eee On
252
The peaks on
the two fides”
rife in oppofite
directions,
Limits of per-
manent fnow,
and of vegeta-
tion.
KEMP MADE TO RESEMBLE COTTON.
‘On approaching the peaks that rife from this flat, the ftrata,
which are of compaét fhelly limeftone, rife at an angle of 45°,
but in a dire€tion contrary to that of the ftrata that form the
{mall peaks on the northern, or French fide. Thus thefe ftrata
as they rife diverge like the fticks of an opened fan, the vertical
ones conftitute the fummits ; a remarkable arrangement, which
Cit. Ramond afcribes to a fliding of the ftrata, rather than a
rifing up, hg Sir fo called, from a depreffion of the other
end.
Cit. Ramond has afcertained the limits of permanent finds
and of vegetation, for this lofty part of the Pyrenean chain,
The fnow terminates at 2440 metres. The laft trees are
Scotch firs, which reach 2150 metres. Next come the thrubs,
of which the juniper is the higheft. At 2760 metres are found
— the ranunculus parnafie-folius, the faxifraga Groenlandica, &c.
The author’s
former experi-
ments.
Subfequent at-
tempts.
then the artemifia rupefris of Lamarck; and laftly, round the
very peak of Mont-Perdu. on rocks too floping to retain the
fnow, grow the cerajtium, perhaps the alpinum of Linneus,
and the rofe-flowering aretia alpina.
Xl.
Notice of a Method of giving the Appearance of Cotton to Hemp
or Flax*. By Cit. BERTHOLLET.
Wate I was engaged in the application or the oxige-
nated muriatic acid, to the art of bleaching, I made experi-
ments on flax, and I inferted this obfervation in the firft
volume of Elemens de Tainture, p. 258. ‘“‘ Ihave endeavoured
to bleach flax completely, by the method I make ufe of with
thread ; but although its filaments may not lofe much of their
folidity by this, they neverthelefs acquire fuch a tendency
to feparate and divide themfelves, as renders them much more
difficult to fpin, and they form a thread of much lefs folidity.”
. Since that period different artifts have employed themfelves,
with various fuccefs, in methods of obtaining from flax a
matter analogous to cotton. A Swifs, Cit. Clays has even
formed an eftablifhment fome time ago, in which this kind of
preparation is executed,
* From Journal de L’Ecole Polytechnique, Tome IV, p. 319.
I know
HEMP MADE TO RESEMBLE COTTON. 953
I know not the proceffes which have been heretofore em-
ployed, but I have fucceeded, by means of the oxigenated
muriatic acid, in obtaining a matter more beautiful than any
of thofe, the knowledge of which has reached me.
The very fimple procefs I am about to defcribe, was ex-
ecuted in the laboratory of the Polytechnic School, by Cit.
Gai-Luffac, at that time one of it pupils.
The flax is cut into fragments about fix centimetres long; Berthollet’s
it is covered with water in which it is left forthree or four days; pears
after this it is boiled in fimple water ; it is wafhed with care ;
it islyed, it is put into oxigenated muriatic acid. Four im-
merfions in the oxigenated muriatic acid and four lyes are
commonly fufficient : the operation is finifhed by immerfing it
ina bath of water charged with one two-hundredth part of
fulphuric acid. On removing it from this tepid bath in which
it has been left for near half an hour, it is wafhed with great
“care, and plunged into water charged with foap: it is then
fpread, without being wrung, on hurdles, where it is left to
dry, without, however, fuffering it to become too dry. All
thefe operations, from the firft immerfion to the drying, do
not require more than five or fix hours, when the procefs is
made with {mall quantities.
The flax thus prepared was then fent to Cit. Molar, who Mechanica!
was kind enough to undertake the mechanical operations: he ¢perations.
firft combed and then carded the bleached flax. He ex-
perienced fome difficulties from the knots that were {cattered
through the flax, but this fkilful mechanic foon overcame this
inconvenience. I prefented to the clafs of phyfical and
mathematical fciences of the Inftitute, on the 6th Prairial of
the year 8, a fample of the prepared materials, which was
, equal to cotton in its whitenefs, and other apparent qualities ;
neverthelefs, Cit. Molar found fault with the cottony matter The filaments
_ for being too fhort in the ftaple. are too fhort,
Cit. Bawens alfo manufaétured the cottony matter prepared
in the laboratory of the fchool, with the beautiful machines
which he poffeffes at his manufaétory at Chaillot. He found
no difficulty in the execution, but he alfo found the filaments
“too fhort, although he eee a very fine thread of con-
fiderable tenacity.
It is therefore the inconvenience of being reduced into Propofed re-
- fort filaments-~-which requires to be corrected in the firft ™*4y.
preparation ;
M54
Dire@ions for
the bleaching.
i : ‘ f Hi f H :
HEMP MADE TO RESEMBLE COTTON.
preparation; and I am of opinion one certain method of acs
complifhing it, 1s not to complete the bleaching, but to flop
at the third operation. If four are required for the thorough
bleaching, it muft then be finifhed in the thread or in the
ftuff.
In the operation of bleaching, too ftrong lyes. muft be avoid-
ed, but they muft be made ufe of in boiling. We are con-
vineed that all the means which diminifh the odour of the
oxigenated muriatic acid weaken its a€tion; hence it muft be
employed in a ftate of parily, and we muft not attempt to
preferve ourfelves from its odour, but by the .conftruction of
the apparatus and the mode of application, objeéts which ufe
has rendered eafy: it muft even be ufed in its concentrated
flate, otherwife the operations require to be much increafed.
The procefs was finifhed by immerfion jin water charged
‘with foap; which was not prefied out, in order that the fila~
ments might not adhere too much by drying, but yield eafily
the feparation which isto be performed by the card, But
there is a probability that by preventing too much drying,
the inconvenience experienced in the firft trials would not
The cottony
matter js obtain-
ed equally good
from fine flax or
coarfe hemp,
Probable advan-
tages to be ob-
tained by the
procefs,
take place, and that this immerfron might then be omitted.
It is remarkable that whether the fineft flax. or the coarfelt
hemp is made ufe of, the filaments obtained are of equal fine-
nefs and colour.
This indication will be guide enough to artifts, well ae-
quainted. with: chemical manipulations, in the operation of
bleaching. But I have nothing to fay on the mechanical dif
pofitions of carding and fpinning, becaufe they were not exe-
cuted by me |
If [am sit deceived; this application of a procefs already
old, offers many advantages, becaufe it may change the fa-
brication of thread, which, to’ this Gay, requires the fpinning-*
wheel into that much lefs expenfive, which is executed by.
means of machinery ; and it may convert a rough produ& of
our agriculture, and even fome of the refufe, fuch as that
from rope-walks, into a {ubfance valuable in the arts. This
motive has induced me to infert this notice in the Journal. of -
an eftablifhment devoted to public utility, although it. offers’
nothing new as a {cientilic tei hi
XII. Experimental ,
sine SN
MACHINE FOR CLEANENG CHIMNIES, 255
XII.
Defcription of a Machiné now in aQual and daily Uje, for
cleanfing Chimnies, without the Afiftance of Climbing-boys, and
with much greater Effed than is produced by that Method.
. Communicated by the Inventor, Mr. CoRisTOPHER SMART;
ot Ordnance Wharf, Weftminjter Bridge. W.N.
Bivisee humane-perfon muft have beheld with pain and re- Machine for
pret, the infant vitims of a’! thy and difgufting operation, are chines
who ‘are expofed to daily fufféring, and too often to per=
manent ‘difeafe ‘and ‘decrepitude, without the hope of fub-
fiftence when grown tomanhood. A remedy for the cafe of
thefe unhappy and devoted children was long ago attempted
by the amiable and benevolent Jonas Hanway; and within
the laf twelve months, another philanthrophift, James Hebdin,
efq; has aétively exerted himfelf to form a fociety for pro-
moting and eftablifhing methods of cleaning chimnies more
“worthy of a great and civilized people, than one grounded
‘on the mifery of the weak and the helplefs. My gratula«
‘tions, and’ thofe of every good man, will form but a {malt /
‘portion of that reward which the internal confcioufnefs of the
extenfive good he has done muft afford. I fhall therefore dif-
mifs any farther*confideration of the perfonal merits of thofe
‘by whom the attention of mechanics has been dire@ed-to this
‘objeét, or of the artifts who have laboured to folve the pro-
blem offered to their ingenuity ; and fhall proceed to defcribe
‘Mr. Smart’s machine. This apparatus has: been approved
_ upon trial by the fociety lately eftablithed, and has anfwered
“to the fatisfa@ion of feveral well qualified employers, whofe
‘certificates I have feen, by bringing dewn more than the
“ufual quantity of foot, as well as by its efficacy in lofty-or
“winding chimnies, and fuch as dre too narrow’ to be fwept
by bntfitten: It may eafily be inferred, that it muft be fill >
more advantageous in chimnies on fire, than the fhocking
procefs of fending up a child wrapped in rags to’ entet an
a@ual place of combuftion and fuffocating vapour.
Plate XII. Fig. 1. reprefents an apparatus of brufhes, fup-
' pofe four, which are fixed by hinges to a middle. piece or bar,
| fe
3
256
Machine for
clearing chime
nies.
MACHINE FOR CLEANING CHIMNIES,
fo that they thall be capable either of hanging down, parallel
to the bar, or of being opened and expanded, fomewhat in the
manner of an umbrella, until they ftand out at right angles
with the middle piece; in which fituation they are retained
by fmall fupporting bars, refembling thofe of the fame well-
known utenfil. Fig. 2. fhews the bruthes in their collapfed
ftate, with an appendage of tubes, by which the fyftem is
thruft up the chimney. <A ftrong cord is paffed through a
feries of thefe tubes, the lower mouth of every one of which
is opened a little, in order to admit the upper ends of each in
fucceffion. Fig. 5. fhews the fweeping man employed,
thrufting the apparatus up the chimney ; in which the fet of ,
conneéted tubes forms a piece, having enough of flexibility
to accommodate itfelf to the chimney, and yet fufficiently
rigid to anfwer the purpofe of carrying up the fet of bruthes.
When thefe have paffed through the chimney-pot, and given
the ufual evidence of the work being to be performed from
one end of the chimney to the other, the rope is drawn tight
in order to fet the tubes fteadily together, and then fecured
by a thumb {crew feen in fig. 2.—after which, the fweeper
begins to pull it downwards. ‘The rim of the narrow open-
.ing of the chimney-pot caufes the brufhes to expand, and in
this ftate they are retained by the ufual fpring-catch feen in
Fig. 1. and by the fimple and gradual defcent, the chimney
becomes effe@tually cleared of its foot.
Fig. 3. reprefents a curtain for defending the apartment
ied the foot. It is {upported by a rod of metal, having
a cork fixed or ftuck in one of its ends, to afford a {pringy
and perfeétly harmlefs bearing again{ft the infide lining of the
chimney-piece, whether of marble or any other material, and
the clamp which is feen towards the other end of the rod, has
likewife a facing of cork, and is fixed at any diftance, fo as
to afford the oppofite bearing. The fides of the curtain are.
fecured by rods, Fig. 4. which can be lengthened or fhortened
by two parts fliding together, as is feen in the meafuring rule
of fhoemakers, or perhaps more familiarly, in thofe fliding
pencils, which have now been feveral years in ufe.
I. have been affured that the cleanlinefs, decency, and
quiet operation of this engine, are by no means among the
{malleft of its recommendations. I have not yet had an oc-
cafion of trying it in my own houfe, but fhall certainly. do it
on
Rei
Pi)
ON THE CONSTITUTION OF MIXED GASES, &c. O57
on the firft opportunity, and fhall then either confirm or
modify in a future notice, as my own obfervatian fhall direét,
thefe particulars of information, which upon good grounds I
have thought myfelf juftified in now laying before my readers.
W.N.
XU.
Experimental Effays onthe Conftitution of mixed Gafes; on the
Force of Steam or Vapour from Water and other Liquids in -
different Temperatures, both in a Torricellian Vacuum and in
Air ; on Evaporation ; and on the Expanjion of Gases by Heat.
By Joun Darton *.
Tue progrefs of philofophical knowledge is advanced by eS phasis tan
the difcovery of new and important faéts; but much more *. of high ea
when thofe faéts lead to the eftablifhment of general laws. It in the advance-
is of importance to underftand that the defcent of falling Tent of Mience
bodies is the fame every where’on the furface of the earth ;
but frony that and fome other particular faéts to infer the law
of gravitation, or that all matier attraéts with a force decreaf=
ing as the fquare of the diftance, is a much higher attainment
in fcience. In the train of experiments lately engaging my
attention fome new faéts have been afcertained, which with
others, feem to authorize the deduétion of general laws, and
fuch as will have influence in various departments of natural
philofophy and chemiftry:
.-
* Thefe interefting treatifes were read before the literary and
philofophical Society at Mancheftér, in O&ober, 1801, and are
publithed in the fifth volume of their memoirs. The firft, on mixed
gafes, was communicated in the fame month, in a fomewhat different
form, by the author to our Journal, and publifhed in the quarto
feries, vol. V. p. 241.—and, a further communication from him
_ ot the fame fubject appeared in vol. ILI. p. 267 of our prefent feries,
IT have not, therefore, reprinted that effay of the prefent colleétion.
The laft effay in the title, viz. on the expanfion of gafes, is inferted
im the Jaft mentioned volume, p. 130.—Confequently though the
title and introduction refer to the whole four; yet the prefent article
contains only what was wanting to complete the readers pofleifion
of this valuable mafs of experimental knowledge; that is to fay,
the eflays upon fteam and upon evaporation.
Vor. VL—DecemBer, 1803. S As
.Y
958 ON THE CONSTITUTION OF MIXED GASES, bc.
Statement of As the detail of experiments will be bceft underftood and
Feetarn Tavis, (eae application feen, if the laws of principles alluded to be
previous to their
fundamental ex- Kept in view, it may be proper here to ftate them; though it
periments. mutt not be underftood that they were proceeded upon hypo=
thelically in the direGion of thofe experiments, On the con~
trary, the firft law, which is as a mirror in which all the ex-
periments are beft viewed, was la? dete€ied, andafterallthe
particular faéts had been previoufly afcertained. :
4. Mixedelattic 1. When two elaftic fluids, denoted by 4 and B, are mixed “
fluidsdo not —_ together, there is no mutual repulfion amongft their particles 5 %
repel each other.
v
ie
that j is, the particles of 4 do not repel thofe of B, as theydo
one another. Confequently, the preflure or whole weight& %
upon any one particle arifes folely from thofe of itsewn
ki ind. " ‘, i A
2. The fteam of 2. The force of fteam from all liquids is the fame, at equal
any liquid, at diftances above or below the feveral temperatures at which
any given nunmie ‘7° . . 4
ber of degrees they boil in the openair: and that force is the fame under any
fiom its boiling preffure of an other elaftic fluid as it isin vacuo. ‘hus, the
Sosigal ite force of sata Nae ce of 212° is equal to 30 inches of
any other liquid mercury; at 30° below, or 182°, it is of half that force;
ote and at 40° above, or 252°, it is of double the force; fo like-
degrees, the wife the vapour from fulphuricether which boils at 102°, then
raga oe fupporting 30inches of mercury, at30° below that temperature
it has half the force, and at 40° above it, double the force:
and fo in other liquids. Moreover, the force of aqueous
vapour of 60° is nearly equal tohalf inch of mercury, when
admitted into a torricellian vacuum ; and water of the fame
temperature, confined with perfeétly dry air, increafes the
elafticity to juft the fame amount,
3. Evaporation 3. The quantity of any liquid evaporated in the open ait is
ip tine seigg dire@ily as the force of fteam from fuch liquid at its fae ee
force of the ture, all other cireumfiances being the fame. 3
ig staat 4, All elaftic fluids expand the fame quantity by heat : fa
fluids expand this expanfion is very nearly in the fame equable way as that oF |
pauuly by heate mercurys at leaft from 32° to 212°.—It feems probable the ~
. expanfion of each particle of the fame fluid, or its {phere —
of influence, is direétly as the quantity of heat combined with
it; and confequently the expanfion of the fluid as the cube ~
of the temperature, reckoned fiom the point of total privae —
. hon, ; - i
Having
ON THE CONSTITUTION OF MIXED GASEs, &c, 959
Having now ftated the chief principles which feem to be
efiablifhed from the following feries of facts and obfervations,
_ I thall proceed to treat of them under the feveral heads*.
ESSAY II.
On the Force of Steam or Vapour from Water and various other
Liyuids, both in u Vacuum and in Air.
SECTION 1.—Qn Vapour in Vacuo.
THE term fteam or vapour is equally applied to thofe elaitic Steam or vapoug
fluids which; by cold and preffure of certain known degrees, ‘4¢4; Itis
r ¢ ‘i SB an elaftic fluid
are reduced wholly or in part into a liquid ftate. Such are capable of be-
the elaftic fluids arifing from water, alkohol, ether, ammonia, °™!ng liquid by
; . ; cold and preffure.
mercury, &c. Other elaftic fluids that cannot be reduced, Gafes not fos
of rather that have not yet been reduced, into a liquid ftate
by the united agency of thofe two powers, are commonly
denominated yafes. There can fcarcely be a doubt entertains
ed refpeGting the reducibility of all elaftic fluids of whatever
kind into liquids; and we ought not to defpair of effeéting
it in low temperatures and by ftrong preffure exerted upon
the unmixed gafes. . However uneffential the diftinétion be-
tween the gafes and vapours may be in a chemical fenfe, their
mechanical ation is very different. By increafing the quantity Remarkabie dif.
- of any gas in a given {pace the force of it is proportionally in-
ference between
ah i ES é the expanfion of
creafed ; but increafing the quantity of any liquid in 2 given fteam und of
s fpace does not at all affect the force of the vapour arifing from ait a a ee
it. On the other land, by increafing the temperature of any prodigioufly ‘
gas a proportionate increafe of elafticity enfues ; but when the greaters
temperature of a liquid is increafed, the foree of vapour from
it is increaféd with amazing rapidity, the increments of elaf-
ticity forming a kind of geometrical progreffion, to the arith-
metical increments of heat.—Thus, the ratio of the elaftic
force of atmofpheric air of 32° to that at 212°; is nearly as
5: 7; but the ratio of the force of aqueous vapour proceeding
from water of 32° and 212°, isas 1: 150 nearly.
The obje& of the prefent effay is to determine the utmoft Objet of thé
force that certain vapours, as that from water, can exert at Prefent effay<
different temperatures. The importance hitherto attached to
this enquiry has arifen chieffy from the confideration of fteam
* Heré followed the effay I. on mixed gafes: W.N.
$2 as
Reference to
authors refpect-
ing fteam.
Encyl. Britt.
Betancourt.
ON THE GONSTITUTION OF MIKED GASBS, &.
as a mechanical agent; and this has direéted the attention
more efpeeially to high temperatures. But it will appear
from what follows that the progrefs of philofophy is more im-
mediately interefted in accurate obfervations on the force of
{team in low temperatures. Different authors have publifhed
accounts of their experiments on the force of fleam: I have
ona former occafion (Meteorological Effays, page 134) given
a table of forces for every 10° from 80° to 212°. ‘The author
of the article ** Steam,” in the Encyclopedia Britannica, has
done the fame fron 32° to 280°: and M. Betancourt, in the
«* Memoirs des feavans etrangeres” for 1790, fee Hutton’s
Math, Didtion. page 755) has given tables on the fubjeé,
both for vapour from water and {pirit of wine, alfo from 32°
to 280°, But thefe two authors, having aflumed the force
of vapour from water of 32° to be nothing, are effentially
wrong at that point and in all the lower parts of the feale;
and inthe higher part, or that above 212°, they determine the
force too much: owing as I apprehend toa quantity of air,
which being difengaged from the water by heat and mixing
with the fteam, increafes the eclafticity.—In a queftion of fuch
moment it feemed therefore defirable to obtain greater ac-
curacy.
The author’s
method. A
minute portion
of the fiuid is
put into the
upper {pace of a
barometer. Heat
is applied by the
external contaét
of water. The
fall of the mer-
cury fhews the
effect.
My method is this: I take a barometer tube perfeétly dry,
and fill it with mercury juft boiled, marking the place where
it is ftationary; then having graduated the tube into inches and
tenths by means of a file, I pour a little water (or any other
liquid the {ubje@ of experiment) into it, fo as to moiften’ the
whole infide ; after this I again pour in mercury, and, care-
fully inverting the tube,. exclude all air: the barometer by
fianding fome time exhibits a portion of water, &c. of 2 or 5
of an inch upon the top of the mercurial column ; becaufe
being lighter it afcends by the fide of the tube; which may
now be inclined and the mercury will rife to the top manifeft-
ing a perfect vacuum from air.) I next take a cylindrical glafs
tube open at both ends, of 2 inches diameter and 14 inches in
Jength ; to cach end of which a cork is adapted, perforated in
the middle fo as to admit the barometer tube to be pufhed
through and to be held. faft by them; the upper cork is fixed
two or three inches below the top of the tube and is half cut
away fo as to admit water, &c. to pafs by; its fervice being
merely to keep the tube fieady. Things being thus cireum-
ftanced
' a Florence flafk half filled with hot water, into which infert
following table of the force of fteam from water in all the
ON THE CONSTITUTION OF MIXED GASES, Sc. 26)
Ranced, water of any temperature may be poured into the
wide tube, and thus made to furround the upper part or
vacuum of the barometer, and the effect of temperature in
the produ@tion of vapour within can be obferved from the
depretlion of the mercurial column. In this way I have had
water as high as 155° furrounding the vacuum; but as the
bigher temperatures might endanger a glafs apparatus; in-
fiead of it I ufed the tollowing:—
Having procured a tin tube of four inches in diameter and The veffel can- ,
two feet long, with a circular plate of the fame foldered to ae ads
one end having around tube in the center like the tube of a of tin for tem-
reflecting telefcope, I got another {maller tube-of the fame ollie f er
length foldered into the larger, fo as to be in the axis or centre fyphon barome-
efit: the fmall tube was open at both ends, and on this con- 47 nied te
: ‘ thew the de=
flru€tion water could be poured into the large veflel to fill preffion,
it, whilft the central tube was expofed to its temperature,
Into this central tube I could infert the upper half of a fyphon
barometer, and fix it by a cork, the top of the narrow tube
alfo being corked; thus the effect of any temperature under
212° could be afcertained, the depreffion of the mercurial
column being known by the afcent in the exterior leg of the
fyphon,
The force of vapour from water between 80° and 212° Another method
s ( E : by obferving the
may alfo be determined by means of an air-pump ; and the j5ijing point in
refults exaétly agree with thofe determined asabove. Take theair- pump,
and the ftatien
of the barometer
the bulb of a thermometer; then cover the whole with a gage.
receiver on one of the pump-plates, and place a barometer
gage on the other: the air being flowly exhaufied, mark
both the thermometer and barometer ‘at the moment ebullj-
tion commences, and the height of the barometer gage will
denote the force of vapour from water of the obferved tem-
perature. This method may alfo be ufed for other liquids.
It may be proper to obferve the various thermometers ufed
in thefe experiments were dul y adjufted to a good ftandard
one,
After repeated experiments by all thefe methods, and a Hence the force
careful comparifon of the refults, I was enabled to digeft the of fteam up to
232° was bad, '
temperatures from 32° to 212°,
Two important enquiries ftill remained, the firft to deter-
mine the force of fleam from water above 212° and below
‘ 4 32°
?
269 FORCE OF VAPOUR. °
32°; the fecond,to determine the comparative forces of yapour
from other liquids. TThefe enquiries feemed independent of
each other ; notwithftanding which I found them in reality
conneéted.
Examinationof | Upon examination of the numbers in the table, within the
the:progreffion J; its juft mentioned, there appears fomething like a geo-
of the force of “a ’ pp & §
vapour, metrical progreffion in the forces of vapour; the ratio,
however, inftead of being conftant, is a gradually diminifh-
ing one : thus the vies
Force at 32° = __,200 inch.
eo
122 = 3.500 Ratios.
. 8. 57)
212 = 30. 000
If we divide thefe ratios, according to obfervation, they wil]
ftand thus: ‘aes *
Force at 32° = 3200 inch.
: 4, 550
T= 3910
3 3, 846
122 = 3. 500 Ratios,
, 3. DIA Ren
167 2,41. 250.) 380
* "2.666
212 ==> $0:"000
If we divide thefe again, they become,
‘ Force at 32° = »200 inch.
2-17
542 = 9435
2. a9
The = 3910 i
i ae Oe
592 = 3. a0"
~ 1, 92
122 = 33 500 Ratios,
achat ‘1. 84 ar
1442 = 6. 450 ;
- ee ges
Yor = 11. 250 .
ae) Se i |
1893 = 18. 800
; et The Ser
212 = 30, 000
FORCE OF VAPOUR, 298
By another divifion we obtain the ratios for every 13° of Examination of
temperature from 32° to 212°, as under : the progreffion
of the force of
Force at 32° = 3200° inch vapour.
1. 485
43% = 297
1. 465
542 = 4435
I, 45
652= 630
1, 44
Oe 3910
1. 43
8382 1. 290
I, 41
991 1. 820
1, 40
4102 = 2. 540
i 3s
122 = 3. 500 Ratios,
1. 36
133} 4. 760
lL. 35
_ 1442 = 6, 450
1. 33
15h 48. 550
1. 32
LORS (asm). 250
i. 30
178% = 14. 600
1: 29
1892 = 18. 800
Ly QF
I, 25
212 = 30. 000 :
7 Thus it appears that a ratio having a uniform decreafe The ratio of
_ nearly takes place; and we may therefore extend the table ae oP
sof forces at both extremes, without the aid*of experiment, vapour is not as
to a confiderable diflance. Thus affuming the ratios for each aia Sloat
interval] of a 11°94 below 32° to be, 1.500, 1.515, 1.530, lefss
1.545, &c. and for each interval above 212° to be 1.235,
£.220,, 1.205, 1.190, 1,175, 1.160, 1,145, 1.130, 8c. we
can extend the table many intervals of temperature, and
‘determine all the intermediate degrees by interpolation.
This method may be relied upon as a near approximation ;
3 3 however
2@4: FORCE OF YAPOUR.
however it does not fuperfede the expediency of determi-
nation by experiment ; though that is much more difficult
above 212°, and below 32°, than in the intermediate de.
grees; becaufe it is difficult to procure a fteady heat above
212°; and below 32° the variation of force becomes fo fmall
as to elude minute difcrimination. It will appear from what
follows that the extenfion of the table by this method above |
212° is in all probability accurate, or very nearly fo, for |
100° or more. |
TABwLE
Table of the Of the Force of Vapour from Water in every temperature
force of aqueous from that of the congelation of Mercury, or 40° below zero
vapour or fteam. 4
of Fahrenheit, to 325°. 4
ener Meine ett eer rere inches oF || eeeae Te nee ot
Mercury. Mercury, Mercury.
-40° 5013 || 25° 156 54° 9429
"-30 020 || 26 162||55 9443
=20 9030 || 27 ,168 || 56 9458
-10 9043 || 28 31741157 9474
a ——H|' 29 9180 ||58 5490
O 064] 30 ,186 ||59 ,507
1 066 || 31_ 5193 ||60 3524
2 ,068 || — — ||61 3342
3 30711) 32 2200 || 62 3960
4 3074 || 33 2207 |\63 2978
5 ,076 || 34 3214 164 597
6 3079 || 35 9221 ||65 "616
7 082113 9229 ||66 3633
8 3085 || 37 9237 ||67 9655
9 ,087 ||38 1245 ||68 676
10 3090 || 39 9254 ||69 3698
11 5093 || 40 5268 ||70 meee
12 ,096|| 41 3273 71 3745
13 4s) LOO WAR 5283 ||72 RO
14 104 43 3294 ||73 1796
15 3108 || 44 3305 ||74 BRB
16 31121 45 9316 1175 9851
17 116|| 46 5328 ||76 9880
18. 1201/47 3339 ||77 3910
19 ,124.|/ 48 351 ||78 3940
20 ,129 || 49 3365 ||79 971
21 _,134||/50 375 |/80 1. 00
22 9139 ||51 3388 |181 1. 04°
23 3144 1]52 3401 182 1. .07
24 1501/53 7415-83 1, 10
FORCE OF VAPOUR.
Table continued.
‘Temper- _ Force of Vap-
atures in inches of
Mercury.
84° 1. 14
85 ae if)
86 Ube ee |
87 1. 24
88 1.228
89 12
90 Ts 136
91 1. 40
92 1. 44
93 1. 48
94 se
95 1.
96 1. 63
97 1. 68
98 1. 74
99 I. 80
100 1. 86
101 1, 92
102 1. 98
103 2. O4
104 2.631
105 2.208
106 2. OG
107 2.32
108 2. 39
109 2. 46
110 2. 703
111 2. 60
#2 2. 68
113 2. 76
114 2. 84
15 2. 92
116 3. 00
117 3. 08
118 S816
119 3.525
120 De toe
121 Os ae
122 3. 50
123 3.59
124, 3. 69
125 3. 79
126 3. 89
127 | 4. 00
Temper-
atures
128°
129
130
131
132
133
134
135
136
137
138
139
140
el
142
143
14.4
145
146
147
148
149
150
ea
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169,
170
171
Force of Vap.
in inches of
Mercury.
4,
4.
BS
=>
. .
tr Gr Gr or Gr Gr & BOB BOD
«
COOODOOMHHMDHTITIIIMWQDAAAODO
Temper- Force of VaP.
alas Mercury.
PUL POO act)” POR aig
221173 13. 02
BA 174 13. 32
AT 1175 13. 62
60] 176 13. 92
73177 14, 22
86] 178 14, 52
00] 179 14, 83
14/180 15. 45
29/181 15. 50
44|| 182 15. 86
5911 183 16. 23
741) 184 16. 61
90/| 185 17. 00
05} 186 17-40
211] 187 17. 80
3711188 18. 20
531169 18. 6@Q
70} 190 19. 00
87} 191 19, 42 .
05 || 192 19. 86
2311193 20. 32
42]| 194 20. 77
6111 195 21, 22
8111196 21. 68
O1|| 197 22. 13
20|| 198 22. 69
40/1199 23. 16
60 || 200 23. 64
8111201 24, 12
02||202 24. 61
24.\|203 25. 10
46 || 204 25. 61
68 || 205 26. #13
91|}206 26, 66
15 || 207 27.20
41 1208 O7 sade
68 ||209 28, 29
9611210 28. 84
25211 29. Al
541212 30. 00
Se i ee pad
131213 30. 60
43 1214 31. 21
265
Table of the
force of aqueous
in inches of yapor or fteame
266 FORCE OF VAYOUR.
Table of the
forcbaf aquemin Table continued.
vapor or fteam. “ely oh OTOL 4) ORS) BUR "268 BORN ame
Temper- Force of VaP. || Tempers Force of Vap. | | Tempers Force of Vap--.
ature. in inches of ature. in inches of acure. in inches of
Mercury. Mercurys Mercury.
215° —— 31. 83|/252° 60. 05|| 289° ———- 98. 96
216 32. 461/253 61. 00}; 290 100. 12
pA) | 33. 09)|254 61, 92}/291 YOl. 28
218 336, %2\\256 62. 85|| 292 102. 45
219 34. 34\|256 63. 76|| 293 103. 63
220 34, 99}1257 64. 82]| 294 104. 80
221 35. 6311258 65. 78|| 295 105. 97
222 36. 25||259- 66. 75|| 296 107. 14
223 36. 88||260 676.7341) 29T 108. 31
224 57-5326 68. 72)|298 : 109. 48
225 38. 20]| 262 69. 72\| 299 110. 64
226 38. 89]|263 70. 731|3CO lll. 81
DDE 39. 59||264 71. 741/301 112. 98
298 40. 30]|265 HQ RGN B02 114.175
2929 Al. 02)|266 73. 771|\303 115. 32
230 41. 75||267 74. 79|\ 304 116. 50
231 42. 49||268 75. $0|\305 "117.68
232 : 43. 24)|269 76. §2||306 118. 86
233 44. 001/270 77. 85||307 120. 03
O34 44, 78\\271 . 78. 89)||308 J2t. 20
235 45. 58)||272 79. 941/309 1223 437
236 46. 39||273 80. 98]|310 123. 53
237 47, 20/|274 82. OL}\311 124. 69
238 48, 02)|275 So. ao | louie 125. 85
239 48, S4//276 84. 3511313 127. 00
240 49. 67||277 85. 47||314 [28 eRe 5
241 50. 50)\278 86. 5011315 129. 29
242 51. 34||279 87. 63}'316 130. 43
243 - 52, 18}1280 88. 75/317 13ib. 7
244 53. 03//281 89. 87||318 132, 72
945... 53. 88|/282 90. 99} 319 133. 86
246 54. 68|/283 92. 111}|320 135. 00
IAT 95. 541/284 93. 425 321 136. 14
248 56. ‘42/1285 94, 35]|/322 137, 28
249 57. 311/286 95. 481/323 138. 42
250 58, 21\|287 96. 64|| 324 139. -56
251 59, i 288 97. 80}|325 140, 70
Vapor from ‘On Vapour from Ether, &c.
peck eat ag We conie now tothe confideration of vapour from other
follow a general liquids. Some liquids are known to be more evaporable
pe their = than water; as liquid ammonia, ether, fpirit of wine, &c.
others lefs; as, quickfilver, fulphuric acid, liquid muriate of
_ ‘lime,
FROM WATER AND OTHER LIQUIDS,
lime, folution of potath, &c. and it appears that the force
of vapour from each in a vacuum is proportionate to its eva-
porability. M. Betancourt maintains that the force of vapour
from fpirit of wine is in a conftant ratio to that from water
at all temperatures; namely, as 7 to 3 nearly. My firft
experiments with fpirits of wine led me to adopt this con-
clufion, and naturally fuggefted that the force of vapour
from any other liquid would bear a conftantratio-to that of
water. The principle, however, is not true, ejther with
regard to fpirit of wine or any other liquid. Experiments
made upon fix different liquids agree in eftablifhing this as a
general law ; namely, that the variation of the force of vapour
from all liquids is the fume for the fame variation of tempera-
_ture, reckoning from vapour of any given force: thus afluming
a force equal to thirty inches of mercury as the ftandard, it
being the force of vapour from any liquid boiling in the
open air, we find aqueous vapour lofes half its force by a
diminution of 30° degrees of temperature; fo does the
vapour of any other liquid lofe half its force by diminifhing
its temperature thirty degrees below that in which it boils ;
and the like for any other increment or decrement of heat.
This being the cafe, it becomes unneceflary to give diftinét
tables of the force of vapour from different liquids, as one
and the fame table is fufficient for all. But it will be proper
to relate the experiments on which this conclufion refts.
Experiment on Sulphuric Ether.
The ether I ufed boiled in the open air at 102 .—] filled
a barometer tube with mercury, moiftened by agitation in
ether. After a few minutes a portion« of ether rofe to the
top of the mercurial column, and the height of the column
became ftationary. When the whole had acquired the tem-
_- perature of the air in the room, 62°, the mercury ftood at
"
17.00 inches, the barometer at the fame time being 29.75.
Hence the force of vapour from ether at 62 is equal to
12.75 inches of mercury, which accords with the force of
aqueous vapour at 172°, temperatures which are 40° from
the refpeétive boiling points of the liquids. By fubfequent
obfervations I found the forces of the vapour from ether in
all the different temperatures from 33° to 102° exaélly cor-
sefponded with the forces of aqueous vapour of the like
| range
267
The law enuns
Clatcde
Experiments
with ether; in
the barometer,
below ebullition.
268 ON THE FORCE OF STEAM OR VAPOUR
range, namely from 142° to 212°: the vapour from ether
depreffes the mercury about fix inches in the temperature
of 32°,
above ebullition © Finding that ether below the point of ebullition agreed with
water below the faid point, I naturally concluded that ether
above the point would give the fame force of vapour as water
above it; and in this I was not difappointed; for, upon trial
it appeared that what I had inferred only from analogical
reafoning refpe@ting the force of aqueous vapour above the
boiling point, actually happened with that from ether above
the faid point. And ether is a much better fubjeét for expe-
riment in this cafe than water, becaufe it does not require fo
high a temperature,
with the fyphon I took a barometer tube of 45 inches in lect and having
paremmc ters fealed it hermetically at one end, bent it into a fyphon thape,
- making the legs parallel, the one that was clofe being nine
inches long, and the other 36. ‘Then conveyed two or three.
drops of ether to the end of the clofed leg, and filled the
refit of the tube with mercury, except about 10 inches at the
openend. This done, I immerfed the whole of the fhort
leg containing the ether into a tall glafs containing hot water ;
the ether thus expofed to a heat above the temperature at
_ which it boils, produced a vapour more powerful than the at-
mofphere, fo as to overcome its preflure and raife a column
of mercury befides, of greater or lefs length according to
the temperate of the water. When the water was at.
147° the vapour raifed a column of 35 inches of mercury,
when the atmofpheric preflure was 29.75: fo that vapour -
from ether of 147° is equivalent to a preffure of 64.75:
inches of mercury ;“agreeing with the force’ of aqueous
vapour of 257°, according to the preceding eftimation: in
both cafes the temperatures are 45° above the refpeétive
points of ebullition. In all the temperatures betwixt 102°
and 147° the forces of ethereal vapour correfponded with
thofe of aqueous vapour, as per table, betwixt 212° and
257°. I could not reafonably doubt of the equality con-
Experiments in tinuing in higher temperatures; but the force increafes fo
ae ag faft with phe increafe of heat, that one cannot extend the
cluded air was experiments much farther without tubes of very iconve-
ufed as the mea- nient lengths. Being defirous however to determine the
fure of force, f
oree
—
FROM VARIOUS LIQUIDS.
force of the ethereal vapour experimentally up as high as
212°, I contrived to effeét it as follows:—Took a fyphon
tube fuch as defcribed above, only not quite fo long, and
filled it in the manner above mentioned, with ether and
mercury, leaving about ten inches at the top of the tube
vacant; then having graduated that part into equal portions
of capacity, and dried it from ether, I drew out the end of
the tube to acapillary bore, cooled it again fo as to fuffer the
internal atmofpheric air to be of the proper denfity, and fud-
denly fealed the tube hermetically, thus inclofing air of a
known force in the graduated portion of the tube. Then,
putting that part of the tube containing ether into boiling
water, vapour was formed which forced the mercurial co-
lemn upwards and condenfed the confined air, till at length
an equilibrium took place. In this way I found 8.25 parts
of atmofpheric air of the force 29.5 were condenfed into
2.00, at the fame time a perpendicular column of 16
inches of mercury in addition preffed upon the vapour.
Now the force of elaftic fluids being inverfely as the fpace,
we have 2.00 : 29.5:: 8.25: 121.67 inches = the force
of the air within; to which adding 16 inches, we obtain 137.
67 = the whole force fuftained by the vapour, meafured in
inches of mercury. The force of aqueous vapour, at the
fame diftance beyond the boiling point, or 322°, is equal to
137.28, per table. Thus it appears that in every part of
ale fcale on which experiments have been made, the fame
law of force is obfervable with the vapour of ether as of
water.
Experiments on Spirit of Wine.
By boiling a fmall portion of the fpirit I ufed (about one
cubic inch) in a phial, the thermometer fiood at 179° at
the commencement; but by continuing the ebullition it ac-
quired a greater heat. The reafon is, the moft evaporable
part of the fpirit flies off during the procefs of heating, and
the reft being a weaker compound, requires a ftronger heat.
The true point of ebullition, I believe, was nearly 175°.—
The force of the vapour from this fpirit at the temperature of
212°, I found both by an open fyphon tube and one her-
metically fealed with atmofpheric air upon the mercurial co-
Jumn,; as with ether, to be equal to 58} inches of mercury.
, This
. 269
Force of vapor
of ipirit of wines
270...
ON THE FORCE OF STEAM OR VAPOUR
This rather exceeds the force of aqueous vapour at dn equal
diftance from the boiling point; but it is no more than may be
- attributed to unavoidable little errors in fuch experiments. In
Force of vapor
of liquid am-
monia,
of muriate of
lime.
nh Na
Forces of the
vapour of mer-
¢ury and ful-
phuric acid,
a barometer tube the fpirituous vapour at 60°, over the mer-
cury, depreffés the column about 1.4 or 1.5 inches; which
is fomething lefs than the due proportion; one caufe of this
may be the evaporability of fpirits, which in operating om
fmall quantities, quickly diffipates part of their ftrength.
Experiments on Liquid Ammonia.
Liquid ammonia or volatile alkali, the fpecific gravity of
which was .9474, boiled near 140°; in the barometer a
fmall quantity depreffed the mercury 4.3 inches in the tem-
perature of 60°. In higher temperatures it did not produce
a proportional depreffion; becaufe the moft volatile part of
the compound, expanding in the vacuum of the barometer,
leaves the reft more watery, and confequently its vapour muft —
be weaker ; efpecially when the portion ufed is confined to @
drop or two.
Muriate of Lime.
Put a portion of liquid muriate of lime over the column of
mercury in a barometer. The boiling point of the muriate
was found by experiment to be 230°. At 55° the deprefion
was ,22 of an inch;
at 65°—.30
— 70°2-.40 ‘
— 95°—.90
all which nearly agree with the forces of aqueous vapour 18%
below the refpeétive temperatures.
Mercury and Sulphuric Acid.
Mercury boils by my thermometer at 660°, and fulphuric
acid of the fpecific gravity 1.83, boils at 590°. It is very
difficult to determine the precife force of vapour from thefe
liquids in any temperature under 212° ; becaufe at {uch great
difiance from the boiling point the vapour is fo weak as to be
in effcét almoft imperceptible, Following the general law,
the vapours of thefe fluids ought to be of the force .1, mer-
cury at 460°. and fulphuric acid at 390°.—Col. Roi makes
the expanfion of 30 inches mercury by 180, of heat =
5969 or 56513 and in a barometer the expanfion in’ the
fame
4
FROM VARIOUS LItQuIDs, 271
fame circumftances is .5117; the differences are .0852 and
.0534 which fhould meafure the effeGtive force of mercurial
vapour of 212°, nearly, This is in all probability too
much ; as it is next to impoffible to free any liquid en-
tirely from air; and if any air enter the vacuum, it unites
its force to that of the mercurial vapour.
That the force of vapour from fulphuric acid, in low tem-
peratures, is exceedingly fimall, will appear from the ens
fuing feétion,
SECTION Il.
On Vapour in Air.
The experiments under this head were made with manome- Effect of the
ters, or ftraight tubes of different lengths, hermetically fealed sare t
at one end, oF +s inch internal diameter, and their capacities The experi-
divided into equal portions. A drop or two of the liquid, the eesti |
fubjeét of experiment, was conveyed to the bottom or fealed ftoppea by ae
end of the tube; the internal furface was then dried by a wire moveable plug
and thread, and atmofpheric, (or any other air) was admitted cies
into the tube, upon which a column of mercury was fufpended
of gs of an inch, or of 30 inches, lefs or more, according to
the nature of the experiment. By immerfing the end of the
manometer, containing the air thus circumftanced, into a tall
glafs veffel containing water of any temperature, the effect of
the vapour in expanding the air could be perceived. It was
firft indeed neceflary to determine the increafe air unaffeéted by
any liquid (except mercury) would obtain by increafe of tem-
perature: that was done, as will be particularly fhewn in the
next eflay. * The expanfion of all elaftic fluids, it feems pro-
bable, is alike or nearly fo, in like circumftances; 1000 parts
of any elaftic fluid expands nearly in a uniiorm manner into
1370 or 1380 parts by 180° of heat.
It will be unneceflary to repeat in detail the numerous ex- General law of
periments made on the various liquids in all temperatures from go eae A
32° to 212°; asthe refults of all agree in one general rule or gether.
The {pace at a
principle, which is this: let 1 eatelak the ieee occupied by ee oni
any kind of air of a given temperature and free from moifture 5 dire@ly as the
ie i it, in inches of mercury ; f== the preflure and
p= the given preffure upon it, in inch 95S Scapa
i preffure lefs the
Philofophical Journal, VoL. IIT, page 130, force of the
force vapours
27
@N THE FORCE OF STEAM OR VAPOUR.
force of vapour from any liquid in that temperature, in vacuo;
then, the liquid being admitted to the air, an expanfion enfues,
and the {pace occupied by the air becomes immediately, or
ina fhort time = }] +
; or,, which is the fame thing,
ere:
eee
poe
Thus in water for inftance :
Let p=30 inches,
f=15 inches, to the given temp. 180°.
Then, Btn NS for the fpace; or the air be«
p—Sf - 30-19
comes of twice the bulk.
If the temperature be 203°, f=25, and the {pace becomes
fix times as large as at firft. !
If p=60 inches
J =30 inches to the given temperature 212°; then the
BOW i os
160-3
inches of mercury, and at the temperature of 212°, produces
vapour which juft doubles the volume of air.
If ether be the inftance: let the temperature be equal 70°;
then f=15 ; and fuppofe p30; in this cafe the colume of air
is doubled; that is, ether of 70° being admitted to any por-
tion of air, doubles its bulk.
The expanfion of hydrogenous gas and atmofpheric air by
the vapour of water is the fame for every temperature. *
Sulphuric acid does not expand atmofpheric air to any fen-
fible amount by the heat of boiling water.
The theory of thefe faéts is evident upon the principles laid
down in the former eflay: for inftance; let it be required to
explain the experiment with water of 212° under a preffure of
60 inches. Here the air was condenfed into the fpace 1 by
the preffure of 60 inches; but being expofed to water of 212°,
a vapour arofe from it equal in force to 30 inches ; the air theres
fore expanded till its force alfo became = to 30 inches, which
was effeéted by doubling its volume: then the vapour prefling
with 30 inches force and the air alfo with 30 inches force, the
two together fupport. the preffure of 60 inches and the equi+
librium continues. In fort, in all cafes the vapour arifes toa
certain
fpace = 2;, or water under the preffure of 60
PORTABLE FURNACEs 973
,certain force, according to temperature, and the ait adjufts the
equilibrium, by expanding or contraéting as may be required.
The notion of a chemical affinity fubfifting between the gafes Thefe faéts do
and vapours of different kinds, cannot at all be reconciled to = aoe
thefe phenomena. To fuppofe that all the different gafes have chemical affinity
the fame affinity for water might indeed be admitted if we bene eaiand
could not explain the phenomena without it; but to go further, ici
and fuppofe that water combines with every gas to the fame
amount as its vapour in vacuo; or in other words, that the
elafticity of the compound fhould be exaétly the fame as if the
two were feparate, is certainly going far to ferve an hypothefis.
Befides, we muft on this ground fuppofe that all the gafes
have the fame force of affinity for any given vapour; a fuppo-
fition that cannot be admitted as having any analogy to other
eftablithed laws of chemical affinity.
(To be continued, )
(SS Sr ES RE SE TT RTM T|
XIV.
Defeription of the Portable Furnace conftrufled by Dr. Blacl:,
and fince improved, In a Letter from’ Mr. Accum,
To Mr. NICHOLSON.
Dear Sir,
In my Syftem of Practical Chemiftry, Vol. IT. p. 357, I Defcription of
have given a Defcription and Drawing of a Portable Uni- whale in
verfal Furnace, which in the praétice of my profeffion I operations.
found the beft furnace for all chemical operations whatever
which require like aid. The number of furnaces which I
have caufed to be made for different philofophers of that
kind, and the ufeful hints which I have received from diffe-
rent quarters, have materially improved it, that I flatter
myfelf, whether a defcription of this furnace would not be.
acceptable to your readers, particularly to thofe who have
no accefs to the laboratory of the operative chemift ; for
thofe who are familiar with practical chemiftry will readily
allow, that a furnace capable of producing a very low and
very intenfe heat is one of the moft requifite and moft indif-
penfible inftruments of all the apparatus of chemiftry. The
Vor. VI. DecemBer, 1803. X iin great
7 4: PORTABLE FURNACE<
Defcription of great advantage of this furnace (which was fir/t invented bi
ce poe DP Black, and improved by others) above all others Tam ac~-
nace in chemical
operations. quainted with, confifts in confuming as little fuel as poffible,
in producing quickly, if required, a very intenfe heat—in
regulating expeditioufly, and at pleafure, its intenfity—in
duel fut it as direétly, and as fully as poflible, to the fub-
{tances upon which it is intended to aét—and moreover in
enabling the operator to perform his operations in the clofet,
or in any other place, without the rifk of endangering the
conflagration of the furrounding objeéts, which were not
meant to be expofed to the action of heat.
atcoill — ie
h | =U
Sh,
ny ea
— 7
= hii
= | |e
==
<= =
=
=
===
es as
<a
———f
==
This portable univerfal furnace is made of ftrong wrought
iron plates. It is lined with bricks, bedded in fire-proof
loam. Its height without the chimney aa is two feet. The
taner diameter of the cylindrical fire-place meafures ten
inches. The body of the furnace is elliptical; in its upper
part a circular hole is cut, for receiving an iron fand-pot b
which may occafionally be removed and exchanged for an
iron plate. In the front of the furnace there are three open
ingsover each other, furnished with fliding doers, and fitted
with
PORTABLE FURNACE. 275
\
with ftoppers made of crucible-ware. The lower opening, Deferiptios of
is the afh-pit of the furnace ; it,is compofed of two regifter reer in chased
plates, fliding backwards aed forwards in grooves, in order operation,
to diminifh, or enlarge the opening for regulating the heat,
by admitting or excluding air at pleafure. In the fide of the
furnace a hole is cut, furnifhed with a ftopper and door, for
paffing a tube through the fire-place of the furnace; an expe-
dient very neceffary for a variety of chemical proceffes,
fuch as exhibiting ihe decompofition of water; alcohol;
oils, &c. for the preparation of phofphuret of lime, for
pafling gafes over ignited bodies, &c. In either of the
openings in front of the furnace; a muffle may be placed for
performing the procefs of cupellation of gold, filver, &cé
or, the neck of a retort (placed on a ftand in the body of the
furnace) may be paffed through it, for diftillation by the
naked fire ; for procuring gafes which require a high degree
of heat, &c. If the iron fand-pot b be removed; and s
circular plate properly lined with fire-clay be placed in its
room, the furnace becomes converted into a wind-furmace
the fuel is then to be introduced through either of the opens
ings in front. . The iron plate at the top has a hole in the
centre, furnifhed with a ftopper; to enable the operator to
infpeét’ his procefs at pleafure. If the iron-pot be placéd
inverted on the opening of the furnace; it forms a dome; and
it then becomes a reverberating furnace. The iron-pot
when filled with fand, or water; placed in its proper fitua-
tion, ferves as a fand or water-bath, for the proceffes of dif-
tillation by means of glafs retorts, for evaporations, fubli-
mations, digeftions, &c. Coake and charcoal are the beft
fuel, this mixture burns without fmoke; and gives a ftrong
uniform and permanent heat; chareoal and common coal,
or coal only; does likewife very well. The elbow of the
chimney a may be direéted into that of the fire-place of any
apartment.
_ The furnace is furnifhed with ney and may therefore
be eafily moved, according to the convenience of the ope-
ratory. lam; STR;
_ Your moft obedient fervant,
patties FREDERICK ACCUM.
Old Compion-Street, Soho,
Nov. 21; 1803. j
T 2 KV. Obfervationd
Introduction.
Importance of
a fate means of
removing part
of the tongue.
ts tructure
fuppofed to be
very delicate.
OBSERVATIONS ON THE STRUCTURE OF THE TONGUE,
\
XV.
Obfervations on the Struéture of the Tongue ; illuftrated by Cafes
tn which @ Portion of that Organ has been removed by Liga-
ture. By Everarp Home, Ey. F. R. S.*
Puy SIOLOGICAL ‘inquiries have ever been confidered
as deferving the attention of this learned Society; and,
whenever medical praétitioners, in the treatment of -difeafes,
have met with any circumftance, which threw light upon the
natural firu@ture or aétions of any of the organs of ‘the human
body, or thofe of other animals, their communications have
met with a favourable reception.
The following obfervations derive their real importance
from offering a afe and effectual means of removing a portion
of the tongue, when that organ ‘has taken on a difeafed. ation,’
the cure of -which is net within the reach of medicine; and,
asthe tongue, like many other glandular ftru€tures, is liable
tobe affeéted by cancer, it becomes of no fmall importance
that the fa&t fhould be generally known, In a phyfiolegical
view, they tend to fhow, that the internal ftructure.of the
topgue is not of that delicate.and fenfible nature which, from
its being the organ of tafte, we fhould be led to imagine.
The tongue is.made up of fafcsculi of mufcular fibres, with
an intermediate! f{ubftance met with in.no other part of the
body, and a vaft number of fmall glands; it has large nerves
pafling through it; and .the tip pofleffes ans penlity,
fitting it forthe purpofe of tafte,
Savhieshes the fenfe of tafte is confined entirely to the point
of the tongue, and the other parts are made up ‘of mufcles
fittedofor giving it motion; or whether the whole‘tongue is
tobe confidered as the organ, and the foft matter which per-
vades its fubf{tance, and fills the interftices between the fafci-:
culi of mutcular fibres, is to be confidered as conneéted-with -
fenfation, bas not, Ibelieve, been afcertained,
The tongue, throughout its fubftance, has always -been
confidered by phyfiologifts as a very delicate organ ; and it ¢
was believed, that any injury-committed upon it would not
* Philof, Tranfac&t, 1803, p..205. ’
A. : only
OBSERVATIONS ON THE STRUCTURE OF THE TONGUE, 277
only produce great local irritation, but alfo affeét, in a violent
degree, the general fyftem of the body. This was my own
opinion, till I met with the following cafe, the circumftances
of which induced me to fee this organ in a different point of
view.
A gentleman by an accident which it is unneceffary to de- Accident of the
feribe, had his tongue bitten with great violence. The im- itis ha
mediate effe& of the injury was great local pain; but it was and a Sa 4
not attended with much {welling of the tongue itfelf, nor any afble,
other fymptom, except that the point of the tongue en-
tirely loft its fenfibility, which deprived it of the power of
tafte: whatever fubftance the patient eat was equally in-
fipid. This alarmed him very much, and induced him te
fiate to me the circumftances of his cafe, and requeft my
opinion.. I examined the tongue a fortnight after the acci-
dent. It had the natural appearance, but the tip was com
pletely infenfible, and was like a piece of board in his mouth,
rendering the aét of eating a very unpleafant operation, I
faw him three months afterwards, and it was = in nearly the
fame ftate.
From this cafe it appears, that the tongue itfelf is not par-
ticularly irritable ; but the nerves pafling through its fubftance
to fupply the tip, which forms the organ of tafte, are very
readily deprived of their natural aétion; this probably arifes
from their being fofter in texture than nerves in general, and
in that refpeé, refembling thofe belonging to the other or-
gans of fenfe.
There was another circumftance in this cafe which very without inflam=
particularly firuck my attention, viz. that a bruize upon the maton oF. irritae
: i ion to produce
nerves of the tongue, fufficient to deprive them of the fpatms,
power of communicating fenfation, was produétive of no in-
flammation or irritation in the nervous trunk, fo as to induce
fpafms, which too commonly occur from injuries to the nerves
belonging to voluntary mufcles, Iam therefore led to be-
lieve, that the nerves {upplying an organ of fenfe, are not fo
liable to fuch effects as thofe which belong to the other parts
of the body.
The fmall degree of mifchief which was produced, and the Cafe of fungous
readine{s with which the nerves had their communication com- pe eg
pletely cut off, were to me new faéts, and encouraged me,
in
278
which when re-
moved was fol-
OBSERVATIONS ON THE STRUCTYRE OF THE TONGUE.
in the following cafe of fungous excrefcence from the tongue,
which bled fist profufely as at times to endanger the patient’s
life, and never allowed him to arrive at a ftate of tolerable
health, to attempt removing the part by ligature.
John Weymouth, eight years of age, was admitted into
fowed by violent Ste George’s hofpital, on the 24th of December, 1800, on ac-
hzmorrhage.
The portion of |
tongue removed
by ligature.
count of a fungous excrefcence on the right fide of the anterior
part of the tongue, which extended nearly from the outer
edge to the middle line at the tip, It appeared, from the ac- _
count of his relations, that the origin of this fungus exifted at
his birth, and had been increafing ever fince. He had been a
year and a half under the care of the late Mr. Cruikfhank,
who had removed the excrefcence by ligature round its bafe ; ;
but, when the ligature dropped off, a violent heemorrage took
place, and the excrefcence gradually returned, Attempts
were made to deftroy it by cauftic; but hemorrhage always
followed the feparation of the floughs; fo that, after ten trials,
this mode was found ineffe@tual. Jt was alfo removed by the
knife, ten different times, but always returned.
From this hiftory I was led to believe, that the only mode
of removing the difefae was taking out the portion of the
tongue upon which it grew. This was a cafe in which I felt
myfelf warranted in making an attempt out of the common
line of praétice, to give the patient a chance of recovery $
and, -from the preceding cafe, having found that preflure on
one part of the tongue produced no bad confequences on the
other parts, I was led to remove the cxorelveneeg in the fol.
lowing manner,” |
On the 28th of December, I made the boy hold out his
tongue, and paffed a crooked needle, armed with a double li-
- gature, dire@tly through its fubftance, immediately beyond the
excrefcence. The needle was brought out below, leaving
the ligatures ; one of thefe was tied very tight before the ex-
crefcence, the other equally fo beyond it, fothat a fegment of
the tongue was confined between thefe two ligatures, i in which
the circulation was completely flopped. The tongue was
thin in its fubftance ; and the boy complained of little pain
during the dpération, Thirty drops of laudanum were given
to him immediately after it, and he was put to bed. He fell
afleep, continued to dofe the greater part of the day, and
was fo eaf y the next wi as to ae no pa attention,
On
FIERY METEOR,
‘On the fifth day from the operation, the portion of tongue
came away with the ligatures, leaving a floughy furface,
which was thrown off on the I1th day, and was fucceeded
by a fimilar flough; this feparated on the 15th day. The
excavation after this gradually filled up; and, on the 20th
day, it was completely cicatrized, leaving only a {mall fiflure
on that fide of the tongue.
(To be concluded in our next.)
XVI.
ee Account of the large fiery Meteor which appeared on the
Sixth of laft Month ( November.)
279
On Sunday evening at half paft eight, on the fixth of laft © scent of a
month, I was Guddenly furprized with an. illumination re-
fembling that of a flafh of lightning, but more permanent.
The windows of the room in which I was fitting face the
fouth, and were not clofed either by the (hutters or curtains,
but only by venetian blinds ; through which fome of the com-
pany afferted that they fawa large globe of fire moving to
the weftward. My back was towards the window, fo that
I faw only the light which appeared confiderably blue, and
-feemed to laft two, or perhaps three feconds. The bluenefs
in all probability was not more than that of day-light, which,
when contrafted with the light of candles, has a lively blue
tinge.
A {cientific friend of mine, who has favoured me with a
{ketch from which the annexed drawings were taken, was
walking up Princes Street Soho, and needs upon the fudden
appearance of light, when he faw the meteor pafling rapidly
over St. Ann’s church yard, having the appearance of an ob-
long or elliptical folid, with a fhort radiating eruption from
its preceding part, and numerous {parks diverging from its
hinder part. He compares it to the burning of a combutftible
matter in oxigen, and faw it burft into-many fparks, which
inftantly went out and left extreme darknefs. Its direétion
feemed to be to the fouthward of a line fuppofed to crofs
Princes Street at right angles, which eftimate would give a
courfe about W.S. W. This gentleman faw the great meteor
of Auguft.18, 1783, which was then round, and he thinks
the prefent quite as large as that.
y meteors
METEOR OF NOVEMBER 16, 1303.
(Seca
FIERY METEOR.
281
Another friend informs me, that he faw it from a ftation in Account of a
St. James’s Park, near the Queen’s Houfe, rifing above the
horizon, in the eaft towards Weftminiter-abbey, ard that it
paffed over St. James’s Park, and part of the Green Park,
where it was loft behind a cloud. He thinks it remained in
fight for a much longer time than two or three feconds, and
that it did not move in a ftraight line. The courfe by his
obfervation would be about W. N. W.
Another perfon who faw it burft, fpeaks of the | adit
falling down like the fparks of a rocket.
That it. paffed as moft large fiery meteors feem to do, in
the fuperior part of our atmofphere is probable from the
general faéts. A gentleman on Hampftead Heath, beheld
the country fuddenly illuminated; and clearly faw Harrow
Steeple, which is eight miles diflant in a ftrait line, and it was
valfo feen from Dartford in Kent, until it became obfcured by
a cloud; but I had no further particulars refpeéting it.
© Much difficulty. muft arife in eftimating either the courfe,
direétion, or elevation of meteors of this kind, which appear
when totally unexpected, and are gone before the mind can
enter into any courfe of reafoning or eftimate. We are fully
fiery meteors
occupied with the impreffive fenfation they produce, and have |
fearcel y any other means of obtaining a conjeture Ei
pofilions and altitude, but by repeating our obfervations ©
the fpot. On this fubjeét the reader may confult an aaouieel
paper by Sir Charles Blagden 1 in the LXXIV..volume of the
os oaabe Tranfaétions.
‘The lower {ketch fhews the manner of explofion into fmaller
ana
SS
A. Firji
282 MEMOIR GN COLOURED SHADOWS,
XVIL.
A Firft Memoir on coloured Shadows *, By Cit.
J. H. Hassenrratz.
Shadows are ge- We are accuftomed to confider as black, the fhadow
necufy coungeg formed by an opaque body, which intercepts the light falling
black. _ on a white pafteboard, although in reality, nothing is more
difficult to obtain than black fhadows, becaufe it appears, that
to procure a black fhadow, the light muft abfolutely be a
point, and no fort of refle@ed light muft reach the illuminated
furface, '
eee of Ona furface illuminated by alight which has magnitude,
the fhadow is always accompanied by a coloured penumbra.
Whenever the illuminating body is at a greater diftance than
a metre from the body enlightened, and that which intercepts
the light, is nearly five decimetres from this body, the pe-
numbra and thadow have diftinét colours, which are in a
great meafure dependent upon the nature of the combuftible
body which yields the light.
The blue fha- Since the period when Leonardo da Vinei noticed the blue
dow at fun-rife fj ; L : : : :
and fun-fet, is fhadow which is perceived in the morning at fun-rife, and in
notdifferent —_ the evening at fun-{et, this fhadow has been attended to, and
from the general : began :
laws of fhadows, Daturalifts have endeavoured to explain its produétion, as
forming a phenomenon peculiar and diftinét from thofe of
other fhadows.. Neverthelefs, this fhadow has no particu-_
larity ; all the fhadows which are examined are coloured,
eyen thofe produced by the noon-tide fyn of a clear fummer’s
day, which are commonly called black shadows. The co-
loured fhadows are produced by two or more diftin& lights
or by the feparated parts of the fame light which a@ dif-
ferently,
Variety of co- Nothing is more diverfified than the colours of fhadows; on
lore tigsowe. noticing them with attention, we remark among them all
the prifmatic colours: we diftinguifh red, orange, yellow, ~
green, blue, violet fhadows, more or lefs mixed with
black.
The fubjeé is The obje@ of this firft Memoir, is to make known the
ee a great variety of coloured fhadows which may be diftinguifhed
Memoir.
| * From Journal de L’Ecole Polytechnique, Tom. IV. p. 272. ;
ang
3
MEMOIR ON COLOURED SHADOWS.
iS)
(o"9)
GO
and which we have obferved, and alfo the circumftances which
give rife to them. Other memoirs which we purpofe to pre-
fent after this, if the inftitute fhall think the fubject worthy
of its attention, will contain the feries of obiervations we
have made to afcertain the caufes which produce the coloration
of fhadows in a great number of cafes.
We fhali divide this Memoir into three parts: the firft will Divifion of the }
have for its objeét the colour of the fhadows produced by the Me:
reunion of the light of the atmofphere, and that of the fun,
or of the light of the atmofphere and an artificial light, but in
thofe circumftances wherein only a fingle fhadow is percep-
tible: the fecond will contain a defcription of the coloured
fhadows, produced by the light of the atmofphere combined
with reflected lights, and fometimes with the direct light of
the fun: finally, the third will elucidate the coloured fhadows
formed on a body illuminated by two lights, natural and ar-
tificial,
Part the Firft.
If, near a white furface enlightened by the fun and the Obferyations of
light of the atmofphere, a black body is placed which inter- focced Bea
cepts the folar rays, there will be feen on the plane a fhadow
which varies from a greenifh blue to a violet black, con-
neéting through the blue and the violet. The colour of the
fhadow depends on the ftate of the atmofphere, the latitude
of the place, the meridional and northern declination of the
fun, and the time elapfed between its rifing and its paflage to
the meridian, and from the latter to its fetting.
. When the fky is clear, the colour of the fhadow at fun-rife, as produced by
at Paris, varies between blue with a flight tinge of green to ppanige ok tomtom,
violet blue. The firft daysof Nivofe, the fhadow is greenifh-
blue; the firft days of Germinal, blue; the firft days of Mef-
fidor, indigo with a violet tinge ; the firft days of Vende-
miaire, the fhadow becomes again blue to return to a greenifh
blue the firft of Nivofe.
If on aclear day, when the fun is on the equator, the va- as produced by
riation of the colour of the fhadow, if noticed from the in- Rear ehe
ftant of fun-rife to its paffage over the meridian, it will be ob- fon,
ferved that this colour is blue at fun-rife ; that at each eleva-
tion of the luminary above the horizon, the blue changes;
that it becomes indigo, violet; that in the end it blackens,
; and that when the fun i is on the meridian, the fhadow i is ofa
lackith violet,
hia eS Every
284
as produced by
the meridian fun
at different pe-
riods of the
year,
as produced by
difference of lae
titude.
Refult of the
obfervations.
Experiments
with an artificial
light which is
varied,
MEMOIR ON COLOURED SHADOWS,
Every day from the firft of Nivofe to the firft of Meffidor,
the folar fhadow offers different tints, at the moment when
this luminary paffes the meridian. The firft days of Nivofe,
the thadow is violet, a little blackifh; it increafes in blacknefs
daily to the firft Meffidor ; at this period, the fhadow 1s violet.
black.
If the coloured fhadow of the rifing fun is obferved on a
clear day, at the fame period, and in different latitudes, it
will be feen to vary from violet-blue to green, going from the
equator to the pole.
The coloured fhadow obferved at the beginning of Nivofe,
at fun-rife, from Meffina to Skalhot in Iceland, is, at Meffina,
light indigo; at Vienna and at Paris, blue, with a flight green
tinge; at London, Berlin, Copenhagen, Edinburgh, a more
diftinét green tinge; at Peterfburg, a little more green;
finally at Drontheim and at Skalholt, a greenifh tint.
At the fame period, at noon, the fhadow varies, between
Meffina and Skalhoilt, from black flightly tinged with violet to
violet.
The comparifon of the colour of the fhadow of the fun,
with its fituation in the different places where it is obferved,
naturally leads to this firft conclufion, that it is different in
the ratio of the intenfity of its light, compared with that of
the atmofphere, in fact, the rifing fun, on the firft of Nivofe,
having a feeble light in comparifon with that of the atmof-
phere, the fhadow is a greenifh blue; as it rifes above the
horizon, the intenfity of its light increafes, and the fhadow
becomes blue, indigo, violet: finally, when the fun is on the
meridian, its light has acquired its greateft intenfity, and the
fhadow blackens, preferving neverthelefs a violet tinge. |
Comparing in the fame manner the colour of the fhadow
obferved each day of the year at Paris, as well as that ob-
ferved in each latitude on the fame day, it willbe feen, that
it changes from green to violet-black, according to the inten-
fity of the light acquired by the fun; and when in winter the
{un, being but little elevated above the horizon, appears red,
from the feeble light which penetrates the light mifts exifting in
the air, the folar fhadow is green, fometimes a fine grafs green.
To fatisfy ourfelves whether the colour of the fhadow de-
pended on the relation of the light compared to that of the at-
mofphere, we placed the light of a lamp near a while furface,
illuminated folely by the light of the atmofphere; when this
lamp
tS
fore)
wr
MEMOIR ON COLOURED SHADOWS.
lamp was five decimetres from the enlightened plane, the
fhadow caufed by an opaque black body wasblue. On bring-
ing the lamp nearer the colour of the fhadow changed fuccef-
fively; from blue it changed to indigo, from indigo to violet,
and the violet blackened gradually, When the lamp was very
clofe, the fhadow was ofa violet black colour, exaétly fimilar
to that produced by the light of the fun ona clear f{ummer’s day.
This experiment fucceeds very well on days when the fun is
hid by clouds, all bodies are then illuminated by the light of
the fky.
A fimilar refult may be obtained by the inverfe method, with an artifie
that is to fay, by illuminating the furface with an artificial Saue cehioe
light of conftant intenfity, and fucceffively increafing the in-
tenfity of the light of the fky. i
If ina dull morning, before the appearance of twilight, a
white furface is illuminated by the light of a lamp placed at
five decimetres diftant from the enlightened furface, the
fhadow of an opaque black body placed at a fmall diftance
from the furface, is black very flightly violaceous. As foon
as the twilight appears, the tint changes, the intenfity of the
violet increafes. As the day brightens, the violet of the fhadow
effaces the black tint; at length the fhadow becomes violet,
indigo, and is blue when the light of the day is completely
developed.
Repeated experiments with a taper or a candle, have
given the fame refults.
It follows, from the obfervations detailed, that every General refult,
fhadow, formed on a body illuminated, at the fame time, by
the light of the atmofphere and the dire& light of the fun; or
by the light of the fky and an artificial light, fuch as a lamp,
a taper, a candle, is coloured in all cafes wherein the light
of the fun, or the artificial light is intercepted by an opaque
black body; and that the colour of the fhadow varies from
green to violet black, in the ratio of the intenfity of the light
of the fun, or the artificial light, compared with that of the
atmofphere. But on what depends the colour of the at-—
_ mofphere ? what canfes that variation of colour in the ratio
of the comparative intenfity ? This is what we shall examine
in another Memoir.
(To be concluded tn our next.)
SCIENTIFIC
The juice of
St. John’s wort
affords a red
colour,
and alfo a yel-
low.
Red mott folu-
ble.
Mode of dyeing
with it.
Various sints
produced by it.
SCIENTIFIC NEWS.
SCIENTIFIC NEWS.
Obfervations on St. John’s Wort. By Cit. Bau Nacu.®
Sr. JOHN’s wort; kypericum perforatum, is arefinous plant,
the tops and flowers of which contam a juice foluble in water,
alcohol, and vinegar. With the former two it gives a blood
red colour, with the laft.a fine bright crimfon, When com-
bined with [mineral?] acids or metallic folutions; it affords a
yellow colour, which proves, that it contains two colouring
matters, one, the red, more foluble than the other.
To dyelinen, woollen, filk, or cotton yellow, it is fufficient
to put them into a bath, the water of which is duly impreg-
nated with the juice of this plant, witha eertain quantity of a
mordant.' The beft mordant for this colour is alum combined
with a fuitable portion of potath. The {tuff muft be left in the
bath fome time; for the durability of the colour, and the fhade
produced, depend chiefly on the time of continuance in the
bath, the quantity of the mordant, and the degree of heat
employed, When but little mordant is ufed, the tint is a bright
yellow ; by increafing it the colour is made to incline to green;
and on adding a folution of tin in nilro-muriatic-acid, it affumes’
Alumand potath refe, cherry, and crimfon hues, all with a fine luftre.. Alum
form the proper
mordant,
Stains paper
yellow,
alone does not anfwer well, the addition of potafh being effen-
tial, This decompofes the alam, precipitates its earth, dif-
folves a confiderable portion of it, and this alcaline lt with
an earthy bafe becomes the true mordant in the procefs; the
more becaufe the colouring principle refides in a fubftance al=
moft purely refinous.
The juice of St. John’s wort, united with the notihdat here
mentioned gives a fine yellow colour to paper; and as it pro
and dyesleather, duces the fame effeét on leather, it may be employed with ad=
Contains tan-
nin.
’
Sulphate of iron
converts it into
a concrete refine
vantage for dying fheep and other white fkins.
The plant contains a confiderable quantity of tannin, as I
have been convineced\by means of the folution of glue, and
othér experiments made for this purpofe.
On dropping a little folution of fulphate of iron inte the juice’
of St. John’s wort, a blackifh brown precipitate is formed,’
which has the property of abforbmg oxygen, becoming at:
length infoluble in water, and affuming the characters of a con
crete refin.
* From the Aaxales de Chimie. :
Having
\
\
SCIENTIFIC NEWS, 997
Having diftilled a certain quantity of the plant with water, Affords an
the product had a powerful and agreeable fmell, but I could Ranging So
not difcover the leaft trace of effential oil on it. oil.
The juice of St. John’s wort does not diffolve either in ex- The juice does
preffed or in effential oils, but it unites very well with refins. ioe ree
For this purpofe, the juice of the plant muft be dried; which with refins.
may be done very conveniently by exprefling it into earthen nite "3 Mig
plates, and placing thefe in an oven fome time after the bread aie
is drawn; it muft then be powdered, and will readily combine
with turpentine by rubbing them together in a brafs mortar
warmed. This refin, thus faturated with the juice, may be Oilof St. John's
mixed with oils, either effential or expreffed ; and on combining “°™
it with oil of olives, the oil of St. John’s wort of the fhops may
be formed, which, thus prepared, poffefles evident virtues.
If it be incorporated with linfeed oil, and a fmall portion of Makes a fine
oil of turpentine be added, a fine red varnith is produced, ae gna aie:
which may be advantageoufly employed for coating articles of
furniture made of wood.
Mr. RICHARD KNIGHT, who-is well known to the
philofophical world for the very complete Magazine of Chemi-«
cal Apparatus of all kinds he has for feveral years paft efta-
blifhed in Fofter-Lane, has favoured me witha letter, in which
he very fatisfactorily fhews that the inftrament in Plate X. of
our laft number, was not invented by Mr.. Accum, but by
Mr. W. H. Pepys, about three years ago, and has ever fince
been an article on fale in the catalogue of his warehoufe. The
title to Mr. Accum’s paper was written by myfelf, as almoft
all the titles are; and I wasled to eall him the inventor from
the tenor of his paper. Immediately after the publication of
Jaft number, and before I had received any letter from Mr.
Knight, Mr. Accum obferved to me, that he is not the inventor,
and that he firft faw the inftrument defcribed in a German
paper. At the fame time therefore that I have the pleafure to
give Mr. Pepys the undifputed right to a contrivance which,
in point of utility and convenience, is of confiderable value,
I do not fee any moral error that needs correétion.
ACCOUNT .
288
Duncan’s Edin- Ta E copious title page of this ii ae the racer what
he-has to expeét in‘this new edition of a ftock book, the eX 4,
Géllent foundation of which was laid by Dr. ‘Lewis in 1753,
burzh New Dif-
peniatory.
Accum’s lec<
tures on che-
miitry.
a a ee ‘ eS Si eG
ACCOUNT OF ‘NEW BOOKs,
arn
ACCOUNT OF NEW BOOKS.
i he Edinburgh New Difp wiifaaeiealé containing, I. The Elements
of Pharmaceutical Chemiftry : 11. The Materia Medica; or,
the Natural, Pharmaceutical ‘and Medical Hiftory of the differ-
ent Subjtancesemplo wed, in Medicines 111. The Pharmaceutical
Preparations and Compojit Hions; including complete andaccurate
' °Tranflations of the 8v0. Edition of the London Pharmacopeia,
publifhed in. 17915; Dublin Pharmacopwia, publifhed in 17945
and of the New Edition of the Edinburgh Pharmacopaia, pub-
lifhed in 1803: ‘Jlluftrated and explained in the Language, and
according to the Principles of Modern Chemifirys With many
‘new and ufe eful Tables, and feveral Copper-plates, explaining the
mow Syften. of Chemical Charaters, and reprefenting the moft
ufeful Pharmaceutical Apparatus. By ANDREW DuNCAN, Jun.
*iM. D. Fellow of the Royal College of Phyficians, and, Royal So-
» ciety of Edinburgh, and Aociate of the Linnean Society.of Lons
don. 80. 720 Pages,.and 6 Eintetni Henin 1803...
The tranflation of the Dublin Pharmacopevia muft-be.an ac-
ceptable addition, and the introduétory Epitome of Modern’ —
Chemiftry, a knowledge: of which’ is: indifpenfable ‘to: thofe
who would’ tnderftand Pharmacy as a fcience, or pradtife | it.
--with advantage as an art; was loudly called for by the EAN :
improvements made of late’ ‘years in this: branch of feience.
It would take up too much room to give the titles of the
feveral new tables, which ‘are albufeful? and Dr. D. ‘appears
to have availed himfelf of every ‘thing in the ‘field’of modern’
difeovery, or in the beft foreign Pharmacoparias, that was con=- —
fiftent with the plan of the work, (Pe aie
Sa ana j i Mie cc
oh: .
Mr. ACCUM, who has refigned his gratuitous fervice | as
to enter on a Courts of Le@ures on: Pradtical Chemiftry, and
its Application to Agriculture, Arts, and Manufa@ures. They
will comprehend diftinét Series of Le€tures on Popular Che-
miftry, Operative Chemiftry, Mineralogical Chemiftry, Agri-
cultural Chemiftry, and Galvanifm.
Philos. Jownul \il Vt PU, Lp ih
De Wellartont?
on’ O Ver pesprccil fy ofracteon ‘
QL? Youngs Gpparabus |
4 OUMGS & efecer
to Sllustrate the Doclune
of DBeep erdlenance/
Oxporim enet- ity
f Ve Velocity CNfaler
Ge Lertical Tipe. B04
SBIR.
SS
GG ww LAAAAAAAAALAA AAA
SG Gg Hp pALL09 9
SS
YY LG
y
"\
Philos Journal Vol.IT.PU.IL, p. 384.
. (@
ieee
#- _
cs a |
gf BN
Cant
:
| | |
— —————
Sa
:
TZ Pl. Il. p. 384.
| Philos. Journal Vol. VI. Pt.
| ANN
ny
| } | I y
hi | yh
ie
| e | | | lili
NU AUT | NN
nil |
I)
i) | .
|
fist
Pa aeniih +
‘ iw
at
Philos, Journal, Vol. VI. Pl.IV. p- 384.
UD rshel ig onagnified : Sona oF |
Va le: dame Ofar ar different SD2ed .
£uy.1.
a ~ 3 4 F 6 7 8 g 10
oe eA wy, é ee is BOE. 5). oS ea ty A coeng
Water LD L0-0tIW lata, bamdenbees, EL
Fig. 2.
a Le’ 4% 1% Bey
fre Autlomscal he left Lallins LC
fa
C .
~
= >
a '
2
; /
7, 4
;
4 ’
; > ag
’
Phdlos. Journal Vol.V1. PLVL p44.
| Aurwnace fer Ovapora lion ty veg wlater Sempre 2alhire:
dahon. fru viallel Nath Pore AB
{
QW \’"blbl»h SGWQ.WHu00wwW”Bbu'’#sE’.F”F”ivn MGS \ XW ll Ro
AN
Sante ee Zt WN
Lee un the tine ©, G SS
SS
\\
| \
es Metres of 39 4 Inches.
q 2 3 4 o
Vution Se. Rugxell @!
* ~
.
ih
«
yi s
> .
“1 <
.
’
-
ee
~ ‘-
!
{ -
k
yt
TNE
Tit
iis
TM
Ts
TTT oo
Sry
=F
=n
Prilos. Jranal Vou.Vl Pl. Vip.144.
k
i ume
ul
HE j (ii | |
|
|
HIE
i
I
WE il
l
iii il ml i
| )
il
Wi. .
Piulos. Journal Vou.Vl. Pu ViLp.144.
Se
es a
rma NTR NE NATIT TU ah
Hite aN aa i ay { Ni \
AN)
M ok
ng:
,
ANP QMNAD «
A
Fm
Hua
CYL
AI AAINEC
CVVLE’
é
MW
———
aS
O7 Oaths
Philos. Journal Vol.VE PLIXp.224.
¢ Gombe (FU
I
ys
method o sf fio?
2
e
roy
acro#wld “ic 4 O bere a/b “a OI.
Drawn by Blunt Engraved byMutlow Rupiell @? .
Pralos. Jounal Vol VI. PUX. p. 224.
Ap aalis
fo by
ee be iy
and: fer
See
Drawn by Biot. Engraved hy Mutlow Rupsell Oo:
t
i>
Os Philos. Journal VOLVIFUAL p.22 4.
||
iF
Ha
ro
a
a, © i
{|| \ Sa
|
|
at
:
*
Engraved by Mutlow Rujiell Gl
\
Philos. Journal Vol.VI-Pt.XILp. 224.
ippenny yg Wy, a
nfo, oe Yeoupg hj «
2g YY iy bury ffar tof,
PUIUMNMYED
‘ O
ee E r ~
eo — ee eee ee a _- ee a = as Ol Se Sr. eS OS So
Philos. Journal Vol. VL. PUXM. p. 304.
ae a |
Drawn by Blunt.
be
a Ae roan
Philos Journal Vol, VI. PUM. p.304. -
pees aC. reguléting ee, Ay |
£ GUA MAgubis 0 ff }
rl "
ay
|
|
\
4 + ¢ 7 4 Mla
sooo ees WWF —
1
le Uf "V"YY
it H hil z i
UY ntl
— Tz
YW,
fs
S:> ‘il CO
yy, ae
LLU
LZ
Z| ll“
INDE X.
A,
Accum, Mr. on the combinations of
fulphur and phofphorus, 1-—Analyfis
of the Egyptian heliotropium, 65—
Defcription of an apparatus for drying
chemical produéts and for congelation,
212——LetterrefpectingAuguftine earth,
214—Defcription of an improved por-
table univerfal furnace, 273
Acetite of lead, remarks on, 223—Two
fpecies of, ib.
Acid, benzoic, found in ambergris, 182
——, gallic, cannot be obtained pure from
bark, 34
——, nitrous, decompo(ition of, by phof-
phuret of fulphur, 5
we——, phofphoric, is cryftallizable by long
keeping, 131 .
——, prufiic, new procefs for obtaining
it pure, 134 ;
-—, fulphuretted-muriatic, pPoduétion
of, 104——Properties of it, ib.—-Che-
mical examination of, to5—Compofi-
tion of, 107—Remarks on, 108
~=——-, fulphuric, component parts of, 93
—Seems to be produced whenever ful-
phur is acidified or fublimed, 97, 98
=-——, fulphurous, properties of, 93—
Contains fulphuric acid, 94—-Analyfis
of, 95—Is probably a compound of ful-
phuric acid and fulphur, 97
Vor. VI.
/ a
Adams, 235 ,
Adipocire obtained from ambergris, 136
Acroftatic machines, advantages to be
derived from the ufe of, 194—-Experl-
ments with,195— Apparatus for making
terreftrial obfervations from,196—Con-
ditions neceffary to obtain correct re-
fults; 199—~Valuable properties of, ib.
Auguftine earth, queries refpecting, 139
—Method of extraéting, 214—Cha-
ratters of, 215
Aikin, 130
Air is decompofed by phofphuret of ful-
phur, 4—Its moiiture does not impede
telefcopic vifion, 10—Dry, is unfa-
vourable to ftellar obfervations, 13
— -pump, letter from Dr. Prince re-
fpeCting hiss 235—Improvements in,
236—Is the fimpleft form now ufed,
238
Alloys, experiments on the comparative
wear of feveral, 145—Compound, are
real chemical combinations, 160
Ambergris, a product of impaired digef-
tion, 179——Natural hiftory of, ib»—Ex-
ternal qualities of, 130—-Formerly claf-
fed among bitumens, ib.—Geoftroy’s
analyfis of, ibh—-Many varieties in
commerce, 181—Fabrication by art,
ib.—New refearches into the nature of,
ib.—Phyfical properties of, ib.—-Che-
mical properties of, 1$2—-Alcohol iz
the
INDEX.
the only re-agent to be depended on,
¥84—Examination of the produéts ob-
tained from, 185—Recapitulation, 186
=—~Conftituent parts of, 137
Apparatus for drying precipitates and for
congelation, 212
Eudiometric, contrived and ufed
by Dr. Hope, 210
for meafuring the aliquot parts
of an inch, 247
— for meafuring the foree and re-
gulating the emiffion of team, 249
——-——— for raifing water by atmofpheric
preffure, 217
Aqueous humour of the eye, chemical ex-
amination of, 22
“Arachis hypogza cultivated for economi-
’ “eal purpofes, 224
Arfeniated hidrogen gas, chemical analyfis:
and properties of, 200
Aurora Borealis does not affeé& telefcopic
vifion, 33
B.
“Barks, aftringent, chemieal examination
of, 31—Properties of the refidual por-
tions of, 36
Barytes not to be depended on in the ana-
lyfis of fulphites, 94
Baumé, 131
Baunach’s obfervations of St. John’s wort,
286
Bawens, 253
Bayen, 182
Bergman, 74
Beril, Saxon, component parts of, 215
Berthollet on a method of giving the ap-
“pearance of cotton to hemp or flax,
252
Bertholon, 138
Bertrandi, 22
Betancourt, 260, 267
Biggin, 34
Biot, 135
Bifmuth, difference between hot and cold
folutions of, 63
Black, Dr. his theory of heat, 25—His
portable furnace, 273
Blagden, Sir Charles, 281
Body and mind, philofophical opinions re-
{pecting, 161
Bones, foffil, found in America, 247
Bonnet, 173
Boftock, Dr. on the efflorefcences found
on walls, 109
Bournon, Count de, 187
Brandy, method of giving its flavour to
malt fpirits, 140
Briffon, 158
Buckholtz, 63
Bucknall, 124
Buffon, 216
Buildings, their vicinity impedes telefco-
pic vifion, 14
Cc.
Calamines, opinions of authors refpeéting,
74—Analyfis of that of Bleyberg, ib.
External charatters, ib.~-Component
parts of, 76.—Analyfis of the Somer-
fetfhire, ib.—External charafters, 77.
Component parts of, ib.—Analyfis ef
the Derbyfhire, ib.—External charac-
ters of, ib.—Component parts of, 78,
—Analyfis of the ele&tric, of Regba-
nia, ib,—-Component parts of, 79—
General obfervations, 80--Chemical
theory of the compofition of, 32—Has
mot been yet difcovered as an uncom-
bined calx of zinc, 85
Calorimeter, its ufe as an inftrument de-
fective, 29
Camelford, Lord, 2
Candles, on the light emitted by different
fizes of, go—Rules for computing the
proportion of, 9%
Carbonate:
INDEX.
Carbonate of magnefia, native, examina.
tion of, 240—Difference between it
and the artificial, 241
— of foda found efflorefcent on
walls, 111—Method of obtaining pure,
193
Cardan’s padlock, 45
Carlifle, Mr. on a method of clofing |
wide-mouthed veffels, 68
Caft iron, effeéts produced on it by long
immerfion in the fea, 70
Cataract of the eye, conjectures relative
to the caufe of, 25
Catechu, the moft powerful of all the tan-
ning materials, 40o—Comparative value
of, 41
Cement for extreme branch grafting,
28
Charcoal carinot be abfolutely feparated
from phofphorus, 133
Chenevix, on the chemical nature of the
humours of the eye, 21, 93, 203
Chimnies, defcription of a machine for
cleanfing, 255 .
Chrouet, 22
Cinchona, on the febrifuge principle of,
136—Obfervations on the varieties
found in the fhops, 137—Comparifon
between its medicinal virtues and thofe
of gelatine, 138—-Does not contain ge-
Jatine, 225—-Experiments and obferva-
tions on, 226—Contains a new prin-
ciple analogous to gelatine, 228
Cinchonin, the new principle of cinchona,
experiments to prove the exiftence of,
226—Comparifon of its properties with
thofe of gelatine, 228
Clays, Cit. 252
Clouds, effeéts produced by them on te-
le{copic vifion, 15
Coin, obfervations on its lofs of weight by
wear, 147-——Difadvantage of foftnefs in,
148—Lofes but little in ordinary circu-
jation, 150—-Comparifon of the value
of different alloys for, 1§2—Erroneous
opinion refpeéting that of the prefent
reign, 164
Cold, the focal length of mirrors is alter~
ed by, 16—-Experimental proofs of this
effe, 18
Colours obtained from St. John’s wort,
286
Congelation, apparatus for promoting, 213
Conté, 142
Corer, 72
Crawford, Dr. 26
Crocodile, effects produced on atmofphe-
ric air by the refpiration of, 246
Crofthwaite, 118 .
Cryftalline humour of the eye, chemical
examination of, 2g—Is very fubjeét to
diforders, 25 |
Curandau on the imperfeétions of evapo~
rating furnaces, with a new method of
conftructing, 114
Cuthbertfon, 245
D.
Dalton, Mr. on a miftake in Kirwan’s
eflay on vapour, 118—-On mixed gafes ;
on the furce of fteam ; on. evaporation,
and on the expanfion of gafes by heat,
257
Davy, Profeffor, on: he conftituent parts
of aftringent vegetables, and their ope-
ration in tanning, 3%
De Dominis, 56
Delufions, audible, occafioned by debility
of the organs of hearing, 231
Derangements of the animal fyfem, dif-
quifitions on, 229
Defcartes, 56
Divacus, 73
Donkin’s table of the radii of wheels, 86
Dree, Marquis de, 188
Dry-rot, method of fecuring timbers in-
jured by, 120
Dubree, 130
ba Duncan,
ees
INDEX,
Duneay, Dr. on cinchona, 225—-On
gum-kino, 234 S
E.
Earthquakes, their effeéts in South Ame-
rica, 242
Edelcrantz, Sir A. N. his method of rai-
fing water for the purpofes of refrigera-
tion, 41-
Edwards, Mr. an erroneous affertion of
his refpecting the eye-ftop of refleting
telefcopes, 248
Efflorefcences on walls, experiments and
‘-obfervations on, 109—Enquiries into
the origin of, 112.
EleGtricity of the oppofite poles of the
galvanic pile, experiments on its nature
ahd effets, 222
Englefield, Sir H. C. his account of two
halos with parhelia, 54
Eudiometric apparatus conftruéted and
ufed by Dr. Hope, 6%
properties of phofphuret of
_fulphur, 4
Evaporating furnaces, on the conftruétion
of, 114,
Evaporation of liquids, experimental eflays
on, 257
Excrements of mammiferous animals, are
analogous. to’ ambergris and mufk,
180
Extractive matter of vegetables, is moft
abundant in the middle bark, 35—Is
abforbed during the procefs of tanning,
39——Is probably the canfe of foftnefs in
fkins, 40—Mutual a¢tion with tan-
nin, ibe
Extreme branch grafting, a method of re-
‘ftoring: decayed. trees, 124—-General
preparation and management, 126—
Teftimonials of its fuccefs, 128
Eye, its funétions are fubjeét to the laws
of optics, zI—-The chemical hiftory of
its humours limited, 22—-Experiments
on the humours of, in different ani-
mals, ib.
Eye-ftop of. refleGting telefcopes, cor-
reCtion of an error refpeéting the,
247
F.
Fairman, Mr. on the reftoraticn of des
cayed trees by a new method of graft-
ing, 124
Fafcolomes, a new fpecies of quadrupeds,
defcription of, 141
Febrifuge principle of cinchona, memoir
ons 146 ‘
Feeding of leather philofophically account-_
ed for, 40
Fermentation, enquiries into the nature
and caufes of, 221
Pichtegurys
Flax, method of giving the appearance of
cotton to, 252
Fluidity may confit in the change of the
capacity of bodies for caloric, 28
Fogs do not impede telefcopic vifion,
10
Foffil banes, large ones found in both
Americas, 247
Fourcroy, 22, 24, 94, 186—A miftake .
of his rectified, 133
Froft, its ,effe&ts on telefcopic vifion,
i2 ;
Fruit-trees, new method of reftoring de-
cayed, 124 .
Fuel, wafte of its confumption in fur-
naces, 114.
Funcke, 63 P
Furnaces, evaporating, on the conftruc-
tion of, 114——-Caufe of the defective
aétion of, 115—-General remarks, 117
—Defcription of a new, ib,
» portable, improvement in Dr.
Black’s, 273 _
: Gaji-
INDEX.
Gs
Gai-Luffac, 253
Galvanic phenomena, additional experi-
ments on, 221
Garden, 2
Gafes, cannot be reduced to a ftate of
liquidity, 259—Differ from {team or
vapour in their mechanical aétion, ib.
Have no chemical affinity with va-
pour, 273
-——, arfeniated hidrogen, difcovered by
Scheele, 200—Properties of, ibs-New
inveftigations,; 201—Methods of ob-
taining, \ ib.—Phyfical properties of,
222—Action with gafes, ib.—Theory
of its decompofition by oxigenated mu~
riatic acid gas, 204—Tefts to difcover
its prefence, 205, 208—Compofition
of, 206—Habitudes to acids, ibh——-Cu-
rious phenomenon, 207—Habitudes to
metallic folutions, 208—-To various
other bodies, 209
“———, mixed, experimental eflays on the
conftitution of, 257—Do not repel each
other, 258—Are all equally expanded
by heat, ib.
=—, fulphurous acid, abforption of by
water, 93
Gelatine, propofed as a fubftitute for cin-
chona, 138—Comparifon of the medi-
cinal virtues of the two fubftances, ib.
—Is not the febrifuge principle, 225
—Comparifon with cinchonin, 229
Geoffroy, 141, 180 :
Gefner, 72
Glauber, 216
Goetling, 214
Gold, experiments on the comparative
wear of various alloys of, 145—-Stamp-
ing increafes the lofs, 146—Fine lofes
more than alloys, 147—Conclufions,
ib.—=Diftinétion between hard and brit-
tle, 149—Further experiments, 150—
General refults, 152—-Beft adapted for
5
coin when alloyed, 153-~Comparifon
of three kinds of ftandard, 155-—Spe-
cific gravity of, alloyed with different
metals, 157
Grafting, extreme branch, propofed as 2
remedy for decayed trees, 124
Gram, 71
Granet, 131
Gregor, 113
Greville, the Right Hon. Charles, on
meteoric ftones and native iron, 187
Ground-nut. of the Weft Indies, culti-
vated for its oil, 224
Gruber, 47
Gum-kino, an erroneous appellation,
232
Gunpowder, antiquity of the invention of,
i
Guyton’s pyrometer of platina, 89—-Ex-
amination of a native carbonate of mag
nefia, 240
H.
Halos, account of two remarkable ones
with parhelia, 54-—-Theory of, 56
Hanway, 255
Haffenfratz’s firft memoir on coloured
fhadows, 282
Hatchett’s, Mr, experiments and obferva-
tions on gold and its different alloys,
145
Hauy, 74
Hazinefs, effets produced by it on tele-
{copic vifion, 15
Heat, the focal length of mirrors altered
by, 16—-Experimental proofs of this
effe&t, 18—Theories of, 26—Thé
thermometrical degrees of, are to be
taken according to the capacity of the
body, 27—Applied during a change of
capacity does not alter the temperature,
ib.——The experiments to afcertain the
natural zero erroneous, 28—Method of
afcer-
INDEX.
afcertaining the capacity of bodies for,
29—Specific, is proportional to capa-
city for, 30—Theory of its aétion on
fulphite of potafh, 96—Extraordinary
infenfibility toy 139
Hebden, 255
Heliotropium, Egyptian » phyfical proper-
ties of, 65—Analyfis of, 66-—Compo-
nent parts of, 68
Hemp, method of giving the appearance
of cotton to, 253
Herfchell, Dr. on the transit of Mercury
over the Sun’s difk, and on the defec-
tive action of mirrors, 8
Hidrogen, poffibility of its combination
with metallic fubftances, 204
Hoar-froft does not impede telefcopic vi-
fion, 13
Home’s, Mr. obfervations 9n the ftruc-
ture of the tongue, 276
Mope’s, Dr. eudiometric apparatus, 61,
210
Horizon, its Feb, dip is influenced by
the flate of the atmofphere, 51—Caufe
of the errors:in nautical obfervations on
the, 52—Remedy, ib.—-Method of
correcting the errors of the glaffes, 53
Hornblower, Mr. on meafuring parts of
an inch, 247—On the eye-ftop of re-
flecting telefcopes, ib.
Howard, Mr. 187—Apparatus for raifing
water by atmofpheric preffure, 216
Huddart, 57
Hufeland, 164
Humours of the eye, experiments on the
chemical nature of, 22
Hutton, 260
Huygens, 56
Hydrate of zinc, 81
I.
Ice, phenomena of its abforption of heat
during liquefaction, 26
{
Imagination, the difeafes of, require in-
veftigation, 163
Infenfibility to- heat and chemical agents
faid to be poffeffed by a Spaniard,
139
Tron, prefervation of, from ruft, 142
——, caft, effects of long immerfion in
the fea on, 70
——, native, its origin analogous with
that of meteoric ftones, 188
Irvine, Dr. his method of afcertaining the
capacities of bodies for caloric, 29—In=
tended publication of his works, 31
> Mr. his letter in vindication of
his father’s theory of heat, 25
Jars, on the method of clofing wide-
mouthed, 69
Jehangire, emperor, his; narrative of a
metallic ftone that fell in India, 189
Juch, 132
K,
Kant’s tranfcendental idealifm, foundation
of, 177
Kino, is not a gum, 232—Natural hif-
tory of, ib.—Medicinal ufes of, ib.
Chemical examination of, ib.—Is a
fpecies ef tannin, 234—Reference to
Dr. Duncan’s account of, ib.
Kirkpatrick, Col. 188
Kirwan, Mr. 26—A miftake in his effiiy
on vapour rettified, 118
laproth’s analyfis of natrolite, 19%
Krueger, 173
L.
Lac fulphuris, compofition of, 102
La Grange’s analyfis of ambergris, 179
Lampadius, 62
Language of the South gery day 0% copi-
eutnefs of, 246
La
INDEX.
La Place’s memoir on the tides, 239
Lavoifier, 29, 93
Laws, general, their eftablithment of high
value to fcience, 257
Lead, acetite of, remarks on, 223—T wo
{pecies of, ib.
Ve'Cat; 21
Light, on the quantity of, emitted by
candles of different &zes, go—Rules
for computing, 91
Lights, northern, do not feem to impede
telefcopic vifion, 13
Lime, probably hurtful in tanning, 41
Litharge is foluble in acetons acid, 130
Lomet oh the employment of aecroftatic
machines, 194
‘Ludlam, 53
Lute for chemical operations, preparation
of, 140
M.
Machine for cleanfing chimnies, 255
Magnefia, examination of a native carbo-
nate of, 240—Difference between it
_ and artificial, 241
Magnifiers, high, are not calculated for
folar obfervations, 8—Cannot be ufed
while the temperature of the mirror is
fufceptible of alteration, 20
Malt fpirits, method of giving the flavour
of brandy to, 140
Manufcripts, Indian, of the fifteenth can-
tury, 245
Margraff, 1
Maton, 37
Mechanifm for equalizing the motion of a
fteam engine, 218
Mendeljohn, 173
Menftrua, thofe made ufe of in tanning
probably injurious, 41
Merat Guillot, 33 _
Mercury, obfervations on its tranfit over
the Sun’s difk, 8—Has no apparent at-
_mofphere, g—Is truly fpherica!, ib.
Metals are combuftible in non-refpirable
gafes, by galvanifm, 62—May be com-~
bined with hidrogen, 204
Meteor, account of an extraordinary one
feen in France, 135—-Account of the
fiery one of November laft, 279
Meteoric ftones, fall of, 135—Experi-
ments and obfervations on, 387
Mind and body, philofophical opinions re-
fpecting, 161
Mirrors, on the caufes which prevent their
fhewing objects diftin@tly, 1o—Their
focal length affected by changes of tem-
perature, 16—Experiments to afcertain
this faét, 18—The figure of the re-
fiecting furface is injured during this
change, 20—A remedy fuggefted,
Zs
Moifture of the air does not impede telé.
{copic vifion, 10
Molar, 253
Monge’s theory of horizontal refra@tion
objeéted to, 47, 51
Mont Perdu, journey to the fummit of,
250
Moritz, 173
Mofer, ib.
Mountains of South America, curious
particulars refpecting, 242
Muriate of potafh, produétion of, 99
Muffin Pufchkin, 132
Myrobalans, chemical examination of,
37
Nairne, 235
Native iron, 188
Natrolite, natural hiftory of, 191—Phy-
fical properties of. ib.—Analyfis of,
ibh—Component parts of, 193—The
name derived from the foda it contains,
194
Newton, 56
Nicolai
INDEX.
Nieslai on the fpeétres produced by dif-
cafe, 161—Difquifitions on his account,
229
Nitrate of filver, a good téft for arfeni-
ated hidrogen, 208
Go.
Oétant, advantageous method of conftruct-
ing, 220
Ocular fpeétra, nature and caufes of,
229
Oil, from the arachis hypogea, or ground
nut, 224
of rofes, cryftallization of, 134
Orchards, obfervations on the ufelefs trees
in, 124
-Orfted, 22x
Oxide of fulphur, inquiries into the na
ture of, 102
—— of titanium, reduétion of, 62
——, white, of phofphorus, properties of,
133
Pe
Padlock of fecurity, 43—Method of ap-
plying as a defence to the key-hole of a
door, 44
Paramos of South America are piercing
cold, and deftitute of vegetation, 242
Parhelia, theory of, 56
Payffe on the preparation of a lute for
chemical operations, 140
Pearl-afh, probably hurtful in tanning,
41
Pelletier, 15 79, 130
Pepys, Mr. the inventor of the apparatus
for drying precipitates, 287
Phantoms produced by difeafe, 16x
Phofphate of foda, new method of pre-
pating, 63
Phofphoric acid, cryftallization of, 131
Phofphorus, experiments and obfervation»
on its combination with fulphur, 1—
Danger of expofing the compound to
heats 2—Phenomena produéed by the
diftillation of the mixture, 3-—Cannot
be obtained pure, 133—Converfion in-
to white oxide, ik.
5 liquid, produced by diffolv-
ing phofphuret of fulphur in oil, 5—~
Luminous properties of, 6
Phofphuret of fulphur decompofes water
and atmofpheric air; 4—May be em-
ployed as an eudiometer, ib.—«Decom-
pofes nitric acid, g5—Is foluble in fat
oils, ib.—In ether and volatile oils, and
fparingly in alcohol, 6—Accenfion by
oxigenized muriatic acid gas, ibbh——When
inflamed it burns in nitrous gas and ni«
trous oxide, 7—Combuftion in a va-
cuum, ib.—-No change of temperature
produced by its formation, ib.<—More
poifonous than phofphorus, ib. —
Pinel, 140
Poole, 37
Preponderance, apparatus for illuftrating
the doétrine of, 59
Prince, Dr. letter from, refpecting his
air-pump, 235
Produéts of chemical analyfis, apparatus
for drying, 212
Prouft, 36, 132, 201
Pruffic acid, method of obtaining it pure,
aa
Pfycological remarks on the fpe€tres pro-
duced by difeafe, 161
Purification of phofphorus, impoffibility
of, 132
Purkis, 41
Pyrometer of platina, 89
Q.
Quadrant, refle€ting, improvement on,
219
Quadrupeds, news 141
Ramond's
INDEX.
R.
Ramond’s journey to the fummit of Mont
Perdu, 250
Refraétion, horizontal, obfervations on
the quantity of, 46—lIs not the fame as
reflection, 48-—Attributed to variations
in the temperature, 49—-Table of ob-
fervations, 51
Regnier’s padlock of fecurity, 43—Re-
marks and annotations on, 45
Refin from ambergris, properties of, 186
Reverie, a {tate favourable to the pro-
duGtion of fpectres, 229—Inftances,
Oa ar
Richter, 135
Ritter’s experiments on galvanic pheno-
%
_™mena, 221
Roi, Col. 270
Rothe, 73
Rutter, 100
NI
Sabres made of native iron, 190
Schaub, 134 :
Scheele difcovered arfeniated hidrogen gas,
200
Sciences, antiquity of, in South America,
246
Screw, meafuring, 247
Seguin on the febrifuge principle of cin-
chona, 136—Abftraét of his enquiries
concerning fermentation, 221
Sextant, its ufe in aeroftatic obfervations
liable to error, 196—Additional appa~
ratus to remedy the defect, 197—~Suc-
cefsful refults, 198
Shadows, coloured, memoir on, 282——
~ Phenomena of, ib.—Obfervations on
their nature as produced by various
caufes, 283—General refult, 285
$mithfon’s, Mr. analyfis of fome cala-
amines, 74
Vox, VI.
Soda, carbonate of, found eflorefcent on
walls, rr1—Method of obtaining pure,
AQS'Sn Fy
South ‘America, curious particulars re-
{pecting, 242
Spaniard, faid to be infenfible to the ac-
tion of heat or powerful acids, 139
Specific gravity of gold fingularly affected
by alloy, 157—Various circumftances
which affe&t, 158—Caufes of the va-
riation enumerated, 159—Table of,
160 .
Spectres, memoir. on thofe produced by
difeafe, 161—Attempt to explain them
by natural caufes, 229
Speculum of a refie&ting telefcope is af-
feéted by change of temperature, 16
Spinoza, 172
Square, reticulated, method of conftruc-
ting, 247
Stars, caufes which affect their apparent
magnitude, 14, 15
Steam, its force the fame from all liquids
under the fame conditions, 258, 267,
271—Is capable of becoming liquid, 259
—Its mechanical aétion different from
that of gafes, ib.—-Method of meafuring
the force of, 260—Examination of the
progreffion of its force; 262—Tuble of
its force at every degree of temperature,
264—General law of its expanfion in
-air, 271——Has no chemical affinity with
gales, 273
engine, method of equalizing the
motion of, 218
valve, felf aéting and regulating,
249
Steinacher, on pharmaceutical preparations,
"130
Stones, meteoric, 135—Their exiftence
fully eftablifhed, 1837—Hiftory of three
new fpecimens, 188
St. Amand, 188
St. John’s wort, chemical examination of,
286
¢ Su'phur
INDEX.
Sulphate of magnefia found éeflorefcent on
walls, 109
of potafh, compofition of, 100
of foda, prepared from gypfum,
64—Found efflorefcent on walls in two
ftates, 110
of ziné, component parts of, 80
Sulphites, analyfis of, 94—Experiments
on the aétion of acids with, 98
-——— of lead, component parts of,
a
of potafh, component parts of, 95
—Changes vroduced on, by heat, ib.
Sulphur, expetiments and obfervations on
its combination with phofohorus, 1—
Danger of expofing the compound to
heat, 2—Phenomena of the diftillation
of, 3—-May be combined with three
dofes of oxigen, 92—External charac-
ters of, 103=*Oxigenation by compound
agents, 103
Sulphuretted muriatic acid, produ€tion of,
104—Properties of, ih—Chemical ex-
amination of, 1o5—-Compofition of,
107—Remarks on, jos
Sulphuric acid, component parts of, 93—
S¢ems to be formed whenever fulphur
18 acidified or {ublimed, 97, 98
Sulphuroys acid, properties of, 93—Con-
tains fuiphuric acid, 94—Analyfis of,
9§—-Is probably a compound of fulphu-
ti¢ acid and fulphur, 97°
Sumach, chemi¢al examination of, 36
Super-fulphate of potafh, produétion of,
99—Component parts of, 101
Swedenborg’s vifions philofophically ac-
counted fory 171 >
Swediaur, 179
Syphon, improvement in, 218
Syftem, animal, difquifitions on the de-
rangement of; *229 |
i
Tannin, method of obtaining it pure, 33
e=Is moft abundant in the interior whité
bark, 35—Relative quantities in diffe
rent barks, ibs—-Various fub(tances in
which it exifts, 37—Its fpecific agency
always the fame, 38—Affinities and
habitudes of, ibh—Mautual aétion with
extractive matter, 40
Tanning of fkins, experiments ony 33—+
Difference between the flow and quick
procefles, 33, 40—Extraétive matter is
abforbed during the operation, 39—Its
perfection not to be judged of by the
increafe of weight, 4o0—Vegetables
which are of mott value in, ib.
Teas, chemical examination of, 37
Telefcopes, reflecting, caufes of the dif-
appointments in the ufe of, 10
Temperature of bodies, muft be eftimated
according to their capacities for caloric,27
Tennhart, 172
Thenard, 93—Remarks on the acetite of
lead, 223
Thompfon, Dr. on the compounds of fale
phur and oxigen, 92
‘Thought, fpeculations on its nature delu+
five, 162
Tides, memoir on the, 239
Timbers of houfes, method of fecuring
decayed, 120
Titanium, reduétion of its oxide, 62—4
Properties of, 63
Tongue, obfervgtions on the ftructure of,
276—Cafes in which a portion was fe-
parated without affecting the nervous
fyftem, 277 :
Trees, decayed, method of reftoring, 124
—Teftimonials of its fuccefs, 428
Tremler, 71
Tromfdorff, 62—Chemical analyfis of ar-
feniated hidrogen gas, 200
Tungften, is not acidifiable, 134—Me-
thod of obtaining, 135
|
v.
Unguentom nttritum, on the compofition
of, 139 ;
Vana
INDEX.
Vv,
an Marum, 7
Vapour, ftate of, in the atmofphere, 118
—Experiments on that produced from
ether, 266—From fpirit of wine, 269
_ From liquid ammonia ; from muriate
of lime; and from mercury and fulphu-
ric acid, 270—See alfo Steam
Varnifh, a fine red, 287
Vauquelin,~ 94, 101—Experiments on
gum kino, 232
Vavaffeur, Le, 70
Vegetables, aftringent, experiments on,
31%—-Properties which render them va-
luable in tanning, 40
Venturi, 59
Veflels, method of ftopping wide-mouthed,
68, 216
Vifion, telefcopicy caufes which affeét it,
zo-~Can only be diftinét in moift air
and uniform temperatures, 36
Vitreous humour of the eye, chemical
examination of, 23
Volcanos, curious particulars refpecting
thofe of South America, 242
Yon Hombolt, on the natural hiftory of
' South America, and the language and
icience of the natives, 242
Ww.
Walker, Mr. on the proportion of light
from candles of different dimenfions,
go—Improvement in his reflecting
quadrant, 219
Walls, experiments and obfervations on
the efflorefcences on, 109—Enquiries
into the origin of, 112
Water, decompofition of, by phofphuret
of fulphur, 4—TIts fpecific caloric is
greater than that of ice, 26—Method
of raifing, for the purpofe of refrigera~
tion, 41—Velocity with which it Aows
through a vertical pipe, 6¢—<Abforbs
one-eleventh of its weight of fulphurous
acid gas, 93.
- Weather, its effeéts on telefcopic vifion,
14
Wheels, table of the radii of, at a piteh
of two inches, 86—Rules for comput-
ing at any other pitch, 88
White-iead, preparation of, 224
Wiegleb on the antiquity of the invention
of gunpowder, 71
Wind increafes the apparent diameter of
the ftars, 14 *
Woart’s method of fecuring timbers in-
jured by the dry rot, 120
Wollafton on horizontal refraétion, 46
Woltman, 47
Woolf, Mr. on equalizing the motion of
a fteam engine, 218-=Self ating and
regulating fteam valve, 249
¥.
Young, Dr. his theory of halos and par-
helia, 56—Defcription of his apparatus
for illuftrating the doétrine of prepon-
derancey 59—His experiment on the
velocity of water flowing through aver-
tical pipe, ib.
Z.
Zero, natural, inaccuracy of the experi«
ments to determine, 28
END OF THE SIXTH VOLUME.
Printed by W. Stratford, Crown-Court, Temple-Bar,
TreoPeerrty
aeeheg 2078? >a.
+
Ly reree "reget rte
D-O 4 6+ 789 0d-@ R08
Lites Peeed
eee ert
esele ils° STitpratp iene ls
ee et fer
peceettsee oss
5
Fete een ol cena
Str yittorstpeseets Ee Sot eee tse ete
Paed Bes SS
peres seas Tot stere ee
Societ tres see Sree se
tt?
+t?
$338
Bi SySonatocsses
ples ett tae en
Septet ey
peseaieees
Saaeqeeeet es
tee
aheee
ereees
reg
bY
af]
jag
Trott
trozneeeeis
+35
Sasiae
SHE EESS sees
eperenee
Oe tt bla =a
; sr ph ae am ty is
tere Hl niiigerse Hh: Steer
HEH EEE SHE oe Siaiees
+L Eisgesstesiocsses
Prepestisseetissteseess
SSSi3S2 ES
eierecsestetsestrssertes fotterer ite
4333 pith 3 e.
aa23 pexeres
eae sse eat ave Sa oer
Ssewce etede:
Heerlen es
thet
peetat
Hunan
hPL Sisttsssseseses Perpertee
vane hotter
vt Pete
eSsrsessseress
Se See. es
ae :
Stress rake
ereae peacetstd
eoay
.
ee pores. oteee tel Ses oS Tye t+ = :
isegcteseto-s eer erge et tesco: wn oF mers en seeseS
rt" aigipasts rca eeeree esr; Se :
Sig hgteseheceees
pecenees ee
Sir HES i
PES IR ee + ee ate ccevenecenesece: Sugeeca
i
Sosa sslatel ae
Pisee3e=e=-
taste
leséeactastas pite <3 Sesti! Ht 3
rips SS beste rietretttepet r=a24
reeatastestcesserrecscettss Sez Scrteeee
Pep ikes lites tetttepe tt Saipeiet
tisttete tet : tansy
tit 25 Pit rrr et otras
ss dates seca lereleless scenes
eye
$tisheee e
tijjstesi
“obs
St eSstecat tiateces 4 +
Distig deste tieetretrs eter Me pesiticetetitiomr it. oto reer esis Seated
eetiteteteeed bbw wry tuna =<
Tye tip ierer
it
seiecrs ~t ose rs 7
rt riet pepe et ety ot 24
Seen seee lee sete
RTE Soph nes S sit ;
seed 2: y yee E505 §<$4ss0se-s—
Ssetsmelsoe-greleee tee
oa Paes enee avers - oe Srates sigueres ise
Beerecererters
Sispegrcesse
ists isos
sets seresslatsts
+t
pisses pessioe Sayre
ESp hs bos es eens Sheer heres
st: Sietastsoe
poees
iu
poteronan
soate ae isidisetiesinicisu 35222 5425.2
° peospasevess =ete
34 sitstatstigacetelsrergsdsenesesee
: eS: peste saieett Tas sat
$ : 2 Sesagtices prerese terete
: Sietesesets etteretstetsSeree tee ceteses
t Fitstetipeeiebbettesssetspectere sere sees.
$3 tsiSipereelotetigaepset seprtesaass segetesase
+ HES SER ART
et rs rg egsai08 3332322: os9
t ie# stesrttetessa!
ett rete
ee
Sigratscerssdeeeaceeececesd
spires SES TSE ES
Sith Rite
Sit FRAN
Sot:
Serer deste reewres s esecbeernareereset
Stitterespeetetopatesetesrtoret sees See caetel
Releiessspisieeee
$333
eh e4
+
Soest sees.
gSesregos
Hist Sethi
sere Ste ae
scess-isasses
: - bo ee bee ~e- —
eirsstci: :
> THe eres reverie rt
- ‘bas el oes piyssesses 33: Se.
sss
St ta5-
peter ioresrrs sts... ia) Sotese
+ veser HHP EREE SSE
323t aE ae
AinHoisit
pecsscess
abet
-
<252e Porn tee
ee “$s pee posiooe
il-eee
5353 Sesezissacs 3 Steers :
=
pin ee tw tensty where eect.
pears sh esmene
a
+
Prete ees
3. = ase epee easter
rests
o
+ Sexesatseatels
eT ee
peatsteeotacaesee
3,
proce erer smn
peed setisaiscargcsseereeeesteiseses r3
- etagglgzecesess. ee ee
4
on
wot bichpicstetetse ol trertrs
Siig:
eee
egssssesSsssscceeceres e: ss
ratios
tryercer
wo
tise tr
paste PRE E
pewreses ees Stace re > = s-
Petacciese rectre ners no ae So et ene
Se a oe ne
ie eeeeine Tits Saeogsgtesets
on sates
eS pesnsaa ss
pract ee Resse
Live Music Archive
Librivox Free Audio
Metropolitan Museum
Cleveland Museum of Art
Internet Arcade
Console Living Room
Books to Borrow
Open Library
TV News
Understanding 9/11