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THE

LONDON anp EDINBURGH

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

CONDUCTED BY

SIR DAVID BREWSTER, K.H. LL.D.F.R.S. L. & E. &c.
RICHARD TAYLOR, F.L.S.G.S. Astr.S. Nat.H. Mosc. &c.

AND

RICHARD PHILLIPS, F.R.S. L.& E. F.G.S. &c.

“Nec aranearum sane textus ideo melior quia ex se fila gignunt, nec noster
vilior quia ex alienis libamus ut apes.” Just. Lips. Monit. Polit. lib. i. cap. 1.

VOL. XIV.

NEW AND UNITED SERIES OF THE PHILOSOPHICAL MAGAZINE,
ANNALS OF PHILOSOPHY, AND JOURNAL OF SCIENCE.

JANUARY—JUNE, 1839.

LONDON:

RICHARD AND JOHN E. TAYLOR, RED LION COURT, FLEET STREET,
Printers and Publishers to the University of London ;

SOLD BY LONGMAN, ORME, BROWN, GREEN, AND LONGMANS; CADELL;
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AND SON, GLASGOW ; HODGES AND SMITH, DUBLIN:

AND G. W. M, REYNOLDS, PARIS.

Tue Conductors of the London and Edinburgh Philosophical Magazine
have to acknowledge the editorial assistance rendered them by their friend _
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Roy. Geol. Soc. of Cornwall, Hon. Mem. S. Afric. Inst.; LisrarrANn 10 THE
Lonvon Insrrrution, and Secretary To THE Execrricat Sociery.

CONTENTS OF VOL. XIV.

NUMBER LXXXV.—JANUARY, 1839.

Page
Dr. E. Turner’s Chemical Examination of the Fire damp from ‘
the Coal Mines near Newcastle ..........00.---4 e000. 1
Col. R. Wright’s Meteorological Observations during a Resi-
dence in Colombia between the Years 1820 and 1830...... 10
Mr. FTalbot on Analytic Crystals. <0 ii0.0.0c% [e100 6:41) 0.0% 19

On certain Conditions under which Light is received from the
Heavenly Bodies, and on the Importance of investigating them 21

Mr. G. A. Prinsep on a remarkable Heat observed in Masses of
Brine kept for some time in large Reservoirs............. 26

Sir J. F. W. Herschel’s Notice of a Chemical Examination of a
Specimen of Native Iron, from the East Bank of the Great

Beene Iver. 1M SOUbh AtTICAes <> s,s, aie: ale «4, ave alovers he. ce okave 32
Dr. Faraday’s Supplementary Note to Experimental Researches
Pup lectricity., PACVERE SCTICR inno aqcic an Rink oe ws 34

Mr. Ivory on the Equilibrium of Fluids, occasioned by an
Article of Professor Sylvester on Fluids, published in this
Searual ior December PSS8 <0... op vets oh oo Sea eae. 37

Mr. W. R. Birt’s Observations on Shooting Stars made on the
Night of November 12 to 13, 1838, at Whitechapel, London $9

Prof. Schcenbein on the Voltaic Polarization of certain Solid

PRIDE AG, STUUEANICES 0, «Sci Deve. Sera or eia cm aryl’ eb See 43
Mr. R. Phillips on the Formule representing Chabasie, in a
Better, £0, Professor J ObnStOM soci m< iais.<tohe «em 06h dee an Se ajo 46

Note by Professor J. J. Sylvester on his former Paper inserted
in the London and Edinburgh Phil. Mag. for December 1838 47
Proceedings of the Geological Society, Royal Society, and

SSUrGHOUNICAl MOCIECY Wes. 5.6 Smale cea mea ne eka ak 48—72
BRE ONE ERA yb itera al cit yn gt pial “ita W din oie tn tas, iat aft 72
IAT ACE CRANES." PEt s cn ie Se eels, | uals bis te « apt, bpd Sues 73
Valerianic Ather, by MM. Grote and Otto .............. 74
Action of Sulphate of Ammonia on Glass, by M. Marchand.. 75
NL oo. asic ee =i AMSG flonan (>, a\lale Gis we ays on5% 76
Separation of Copper from Arsenic ..................00. 78
On a Method of distinguishing Strontian from Barytes and

Pep MRELCRIY FUOBCN rs Sok faa elafbs ds Gels el Ns wae nwa ce 78
British Association for the Advancement of Science: Instru-

ments for the Alleviation of Deafness .................. 79
Meteorological Observations for November 1888 .......... 79

Meteorological Observations made at the Apartments of the
Royal Society by the Assistant Secretary, Mr. Roberton ;
by Mr. Thompson at the Gardens of the Horticultural Society
at Chiswick, near London; by Mr. Veall at Boston; and oy
Mr. Dunbar at Applegarth Manse, Dumfries-shire...... . 80
a2

iv CONTENTS.

NUMBER LXXXVI.—FEBRUARY.

Page
Major Sabine’s Comparison of the Magnetic Lines of no Dip
and of least Intensity a fo----- <4 2+ <2") ae aera 81
Mr. F. Watkins on the Evolution of Heat by Thermo-Electri-
sig fos omy OSU erty PT ee 82
Mons. Wm. C. Zeise’s Preliminary Notice of some Experiments
on the Action of Acetone on the Bichloride of Platinum
(Platin Chlorid).."/. 5-0-2852 Susur t es ee 84
Prof. J. F. W. Johnston on the Composition of certain Mineral
Substances of Organic Origin. Nos. VI. VII. VIII. Mineral
Reams he ek los ioe om ae aaa gies aie ee 87
Col. R. Wright's Meteorological Observations during a Resi-
dence in Colombia between the Years 1820 and 1830 95
Mr. T. Hopkins’s Observations on Malaria, with Suggestions
for ascertaining its Nature; read before the Literary and
Philosophical Society, Manchester, Nov. 15, 1838.....--- 104
Prof. Forbes on the Colour of Steam under certain Circum-
atantes.* i 1, cies t s.ss soem eke Speier ues ae aaa Sean 121
Remarks on a Paper in the Philosophical Magazine for Decem-
ber 1838, on a certain demonstration of Euclid ......---- 126
Notice of the Electrical Excitation of a Leather Strap con-
necting the Drums of a Worsted Mill: in a Letter to Dr.
Faraday from the Rev. T. Drury os (ee certs oie oe 126
Mr. W. R. Grove on Voltaic Series and the Combination of
Gases by Platinum...2. 5. 7.025: a+ 3 See 27
Proceedings of the Royal Society, Geological Society, and the
Cambridge Philosophical Society ...-----+++-+0: + 131—151
Equivalent of Carbon and Composition of Naphthaline .... -. 152
Composition of Wax.:.:.. 22. - +s esse ee rertst tres 154
Amilén. ‘Oil’of Potat6es 272. s. wel sl con's er to ins ae 156
‘Action of Chloride of Zinc upon Alcohol...-..--+++--- +++ 156
Action of Spongy Platina .....-----++ssssctr creer t tt 157
Mr. Brayley’s Lectures on the ‘Mineralogy of the Arts......-- 158
French Expedition of Discovery to the South Polar Seas .... 159
Curious Habit of Earth-worths . - -.)..-- 9. on +> 2 Ste See 159
Meteorological Observations >. [See «seems ee rile emia 159
Publ hee ower eae wie Shit gee Rete 160
NUMBER LXXXVII.—MARCH.
Prof. Faraday on the general Magnetic Relations and Charac-
ters of the Metals: Additional Facts ...-.-++-+++s+0+7* 161
Dr. Kane’s Notice on the Theory of the AMthers....----+--- 163
Mr. J. ''ovey’s Researches in the Undulatory Theory of Light,
continued ; on the Elliptical Polarization produced by Quartz.
Patt Te | an yin vie pie ein oie ora > hr a Sa 169

Dr. J. M. Winn on a remarkable Property of Arteries consi-
dered as a cause of Animal Heat

Gm ata (eile swf alyet she) S10 Se

174

CONTENTS. vi

Pa
Rev. J. Grooby on the Passage of the Moon across the Pleiades
in March, August, September, and November, 1839....,. 177
Col. R. Wright’s Meteorological Observations during a Resi-
dence in Colombia between the Years 1820 and 18380 .... 179
Mr. T. Webster’s Letter to Professor Forbes on his Communi-
cation’ on the Colour of Steam in the Philosophical Maga-

Zine ol sHebrianyel $39) «527. erase be Laide: a ueaea de. 184
Mr. J. T. Cooper’s Remarks on Hydrocyanic Acid.......... 186
Prof. J. J. Sylvester on the Motion and Rest of rigid Bodies.. 188
Sir D. Brewster on the Colours of Mixed Plates............ 191

Mr. H. F. Talbot’s Account of the Art of Photogenic Drawing 196
Proceedings of the Royal Society, Geological Society, and
Astronomical Society ; Friday-Evening Meetings at the Royal

MOSEL IOM gf cio Si5 Fil «ojuse) a>, stat, « MEMES ONS We 211—230
On the Chloro-chromic Acid of Dr. Thomson.............. 230
Fall of Meteorites in South Africa 230,
MOMMIES ms SPURT I in 8 alata fs a¥oiciahs iliytin'a ¢ Sa Bist ssn le ae Ce 231
RIPE NCHDS Lata sich in, fe iain Ahn Ls ctajesase. a s'un's of) sist ache « 232
Alloxanic Acid and Metallic Oxides .......-............ 233
BPE EAL ECINGHD carseat Shc s sar-h ahd sf aeen ouictel d]a cuspeko) Hela see Shoes 233
MTOM MCE nls wim ioaie alee s A eid aes siege tae oe 234
LTT COE 1 BU OA data ats agen pa lie rs hk SL othe hr da ee 234
EEL cde Ta ge Rg oan dee eh ne Aa eiatoeg Ree Ber oe ti 230
Oxaluric Acid and Metallic Oxides...................... 235
Pe MOC PCIe Ora 4. ale ethem: Sadie aes Gah Oh cleat ee 236
Method of distinguishing Trap from Basalt................ 237
Absorption of Azote by Plants during Vegetation.......... 237
Exploration of the Indian Archipelago.................... 238
On the Influence of Native Magnesia on the Germination and

Fructification of Vegetables, by Angelo Abbene.......... 238
Meteorological Observations for January 1839 ............ 239
ee MAC! cite his cies eae oe ca tele te ba ae 240

NUMBER LXXXIX.—APRIL.

Rev. Prof. Sedgwick and Mr. Roderick Impey Murchison’s
Classification of the Older Stratified Rocks of Devonshire and
SRE EEE ME, Seite teats: fase a) =, Ciateiape vue spe oa gas OE a feae 241

Mr. J.O. Halliwell on a very ‘particular and curious Account
of the Comet of 1472, from a contemporary MS. Chronicle

MOTEMMIMIBE CADTAIN oe cit ns eens ccs ss tes cine nee sees 260
Rev. B. Powell’s Observations on some points in the Theory of
iia PADMA OE PAPE i 21h. Nrarats ein os a= ate ac Sa eee ot osas 261

Mr. J. Maclean’s Meteorological Observations made during
Voyages inthe Atlantic and South Pacific Oceans ; and Alti-
tudes in the Vicinity of Lima measured by the Sympieso-
Leal dele nd sional eters nen phe) tae ater cnn age ya apy iol -verievel rete tay 268

Mr. Ivory (The Bakerian Lecture) on the Theory of the
Astronomical Hefractions' sn st: vcs sede vawe cues eaten 276

vi CONTENTS.

Page

M. Quetelet’s Memoir of G. Moll, LL.D., Professor of the ;
Physical Sciences in the University of Utrecht, and Member

of the Academy of Brussels .......-..--00-2 e+e es eeee 288
Prof. J. J. Sylvester’s Note on Definite Double Integration,
Supplementary to a former Paper on the Motion and Rest

co) a | er i A CMe Is IG thal des he b's ac 298
Dr. J. Lhotsky’s Notice of a Mineral Spring, Menero Downs,
N.S. Wales ...... 300
Proceedings of the Geological Society and Astronomical So-
BIeby feed ee PS a. Cee ee ee 302—317
Postscript to the Communication of Prof. Sedgwick and Mr.
IMiurGhisom's ira2508) toe oo) ovosclte. 20 ot suet tel terete ste eke hot ee 317
Mr. Crosley’s Pneumatie ‘Telegraph. .............00.- 2.0. 317
Meteorological Observations... 12. 0.5... . 0 eee ede ce eee ees 319

NUMBER XC.—MAY.

Mr. Tovey’s Researches in the Undulatory Theory of Light.
Part II.; on the Elliptical Polarization produced by Quartz 321
Dr. G. Bird’s Observations on some of the Products obtained
by the Reaction of Nitric Acid on Alcohol.............. 324
Prof. Plateau’s Answer to the Objections published against a
general Theory of the Visual Appearances which arise from

the Contemplation of Coloured Objects ................ 380
Prof. Johnston on the Constitution of the Resins .......... 340
Mr. Ivory (The Bakerian Lecture) on the Theory of the

Astronomical Refractions: (2. 2). 0.2 = glass ele = eco * fe ee 342
Prof. Phillips's Remarks on a Note in Prof. Sedgwick and

Mr. Murchison’s Communication in the last Number...... 353
Rey. Prof. Sedgwick and Mr. Murchison’s Supplementary Re-

marks on the ‘‘ Devonian” System of Rocks .. .......... 354
Rey. D. Williams on the Classification of certain Geological

Formations in Devonshire’... 7 0ige% eae et os eee 358

Proceedings of the Royal Society, Linnzan Society, Geologi-
cal Society, Cambridge Philosophical Society, Royal ‘Insti-

tution, Royal Academy of Sciences of Paris ........ 359—388
Latanimn, a new Metal:,.’..:....5 ,2ctye ba. an, oe eel 390
Fall of Meteorites at the Cape of Good Hope.......:...... 391
Selenturet'of Mereury 0.5 s= 722 oo ee eee ee e090 ee
Nonexistence of Carbonates of Quina and Cinchonia..:..... 392
Mica containing Potash and Lithia ....................0 393
Rose Mica Tepidolite. 0. 5 0) eA Ye we + ee 393
Meteoric Iron from Potosi. « si:< 21/24 2c 25. ack eae . 3894
Phosphorescent Power of Electrical Light ................ 394
On the Preparation of Selenic Acid, by H. Rose............ 396

Analysis of crystallized Perikline, by Mons. C.T. Thaulon.. 397
Cissampelin, a new Vegetable Compound ...... Fy 9 397

CONTENTS. vil

Page

Analysis of crystallized Oligoclas from Arendal or Soda-
Spodumene, by Robert Hagen.............-.---0+---- 398
Action of Acids on Iodide of Sodium, by Justus Liebig.... .. 398
Meteorological’ Society, «.).- 2!- 2's tee cis)e de ewe wae winless oe 399
Meteorological Observations... .. 50.0... 020e cece ec eeeeee 399

NUMBER XCI.—JUNE.

Mr. Coathupe’s Experiments upon the Products of Respira-
tion at different Periods of the Day.................... 431
Dr. D. Thomson and Mr. T. Richardson on the Decomposition
of Amygdalin by Emulsin
Mr. Trull on the Effects of Light and Air in restoring the faded
Colours of the Raphael Tapestries .................... 416
Prof. J. D. Forbes on the Colours of the Atmosphere considered
with reference to a previous Paper ‘‘ On the Colour of Steam
mnder certain CiIFCUMBtANGes™ | %, wp siaie-sy's adie udu ys Hrefe) oxctera lee. 419
Dr. Beke on the Alluvia of Babylonia and Chaldea ........ 426
Mr. H. Prater’s Observations on the Anti-Inflammable and
Anti-Dry Rot Powers of the Subcarbonate of Soda and other
PME eae ET fees si Veith Te wteciny wait ca niddeal ate auatoleite chats 432
Prof. Plateau’s Answer to the Objections published against
a general Theory of the Visual Appearances which arise
from the Contemplation of Coloured Objects ............ 439
On the polarized Condition of Platina Electrodes, and the
RCO IOE RECORMATY PMCSS 05 c0 aes n-sln leaden cenimaes 446
Proceedings of the Geological Society, Linnzan Society, and
Bdmburch. Society, of Arts.) fecdil. hf lee olet abs 449-463
New Books :—Lubbock’s Elementary Treatise on the Tides ;
Wallace’s Geometrical Theorems and Analytical Formule ;

Faraday’s Experimental Researches in Electricity ........ 464
Beniinie Waemoirs : Part) V o..'2). pcs aioe cote tthe tebe e a tee 472
Preparation of Dichloride of Carbon, by M. Regnault ...... 473
Delvauxene, a new Phosphate of Iron ................00.. 474
On the Use of Ammonia in fixing Photographs, by J. C. Con-

WORM re sas am race CEE: capacatt hts) = a, otp/ ol » als Sedaleiilcl «ote 2 474
Application to Photography of the Light of Incandescent Coke,

BS ene | Learner Pe ol er 475
On the Composition of Idocrase, by H. Hess.............. 476
On the Compositioh of Idocrase from Slatoust, by F. Varren-

SM hein Miu » eeialg article. sale) Sache aol thas Ae wal ve STS on 477
On Terrestrial Magnetism, by M. Quetelet................ 478

Note on the Undulatory Theory of Light, by John Tovey.... 479
Meteorological Observations
~— fi Ce a Rene Pedasaain: edict aiaeietehas 480

vili CONTENTS.

NUMBER XCII.—SUPPLEMENT.
Page
Mr. Henwood on the Expansive Action of Steam in some of
the Pumping Engines on the Cornish Mines ........ O20) $81
Proceedings of the Royal Society, Geological Society, Astro-
nomical Society, Cambridge Philosophical Society, and

American Philosophical Society..............+--- 492—542
Committee of Commerce and Agriculture of the Royal Asiatic

Society of Great Britain and Ireland .................. 542
Separation of Ethyle (Ethule, Ethereum, = 4C + 5H,) by

1) 7) i emmys Ai SAA SRE SS. 55 543
Separation of Phosphorus from its Oxide, by M. Bottger.... 544
Index;<s... Bye aes eee chore SPER cai ucts Mo GRE tha oot 545

PLATES.

I., I1., II. Three coloured Lithographs, illustrative of Mr. Tarzot’s
Paper on Analytic Crystals.

IV. A Map, illustrative of Major Sanrnz’s Paper on Magnetic Lines of
no dip and of least intensity.

V. A Chart, illustrative of the Rev. J. Groozy’s Paper on the Passage of
the Moon across the Pleiades on the 18th of March, and in
August, September, and November 1839,

ERRATA.

Page 51, line 9 from bottom, for Muswell read Muswell Hill.
Page 73, line 25, for disilicate read bisilicate.

Page 151, last line, for Herculis read Hercules.

Page 169, line next above the equation (12.) for b’ read b.
Page 171, second line of (18.) for A; read A’s.

Page 174, line 10, for correctly read approximately.

Erratum in Vol. xiii.

Page 469, line 5 from the bottom, for paralysed read polarized.

Te

THE
LONDON anp EDINBURGH

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]

JANUARY 1839.

IL. Chemical Examination of the Fire Damp from the Coal
Mines near Newcastle. By (the late] Epwarv Turner,
M.D., F.R.S. London and Edinb., V.P.G.S., Professor of
Chemistry in the University of London.*

HE gases subjected to examination were collected under

the direction of Mr. Hutton, by emptying Winchester-
quart bottles filled with water, at the spot where it was de-
signed to collect the gas, and then inserting a well-greased
ground-glass stopper, which was afterwards secured in posi-
tion by cement, and a covering of bladder. About half an
ounce of water was left in each bottle, and the bottles were
sent to me packed in boxes in an inverted position. In most
instances, when the stoppers were withdrawn in the pneumatic
trough, a portion of water instantly rushed in, showing both
that the means of securing the gases had proved effectual, and

[* From the Transactions of the Natural History Society of Northum-
berland, Durham, and Newcastle-upon-Tyne, vol. ii. Part i.] From the
period of its institution the Natural History Society had directed parti-
cular attention to the evolution of gas in coal mines, and many papers had
been read from time to time, when the feelings of the public were most
painfully excited to the subject by the awful calamity at Wallsend Colliery,
on the 18th of June, 1835, described by Mr. Buddle in the preceding paper
[in the Society’s Transactions]. At this time an inquiry was in progress
before a Committee of the House of Commons, which soon after published
its report. It was given in evidence before this Committee, that both
free hydrogen and olefiant gas occur in the atmosphere of some coal mines ;
this, as striking at once at the efficacy of the Davy lamp in preventing
explosions, seemed to be a matter requiring immediate attention in a di-
strict where that instrument is so extensively used, and where its safety
is so entirely relied upon. With this view, immediately after the publica-
tion of the Parliamentary Report, the Natural History Society determined
to institute such an inquiry, and Mr, Hutton was directed to communi-

Phil. Mag. S. 8. Vol. 14. No. 85. Jan. 1839. B

2 The late Dr. Turner’s Chemical Examination of the

that the gases within the mine were in a more rare state than
in my laboratory.

As one of the principal objects of the inquiry was to deter-
mine in how far the gas of different mines varied in chemica!
constitution, it was material to multiply as much as possible
the samples of gas submitted to examination, The number of
samples actually received and examined by me amounted to
twelve. The result of this analysis will be given in a tabular
form at the close of this communication. ‘The general con-
clusion deducible from them is, that the essential and sole in-
flammable material of fire-damp, as formerly found by Dr.
Henry and Sir Humphry Davy, is the light carburetted hy-

cate with the committee of the coal trade to ask their valuable co-opera-
tion and assistance ; for this purpose he addressed the following letter to
Robert William Brandling, Esq., the chairman.
Copy.
“ Newcastle, January 9th, 1836.

«“ Sir,—I beg leave respectfully to state, that at the last meeting of the
Natural History Society, after the reading of a paper on the gas of mines,
it was resolved that the Society should do all in its power to promote an
investigation into the nature of the gas evolved in our different collieries,
for the purpose of ascertaining if any other, and what gas, occurs besides
the common carburetted hydrogen, it having been stated in evidence be-
fore the late Parliamentary Committee, that free hydrogen and olefiant
gas are both to be found in'the mines of Wales. I was directed by the
Society to bring the matter before the Committee of the Coal Trade, and
request their valuable co-operation and assistance in obtaining an exten-
sive analysis by one of the first chemists of the day, so as at once to set
at rest the question as to the nature of coal gas spontaneously evolved
in this district. Dr. Turner was named as the person best fitted for the
task, not only from his great skill as an analyst, but from his extensive
knowledge as a geologist, and the attention he has paid to the chemistry
of nature, so to speak.

« This investigation will not be an expensive one, and it was thought,
from the deep importance of the question as connected with the safety-
lamp, that the Coal Trade would have no objections to join the Society
in the cost. The Society are anxious that this investigation should be
made speedily, as they are about going to press with a conclusion of the
second volume of their Transactions, where they would wish this to ap-
pear as forming an appropriate Appendix to the many valuable papers in
the work connected with our local geology and mining. If the Com-
mittee of the Coal Trade agree to give their assistance in this matter, the
Society will furnish them with any number of copies of the results of the
investigation they may require; and, individually, I most respectfully beg
to offer my personal services in collecting the specimens of gas, and ma-
king such arrangements as will secure their conveyance to London un-
adulterated. “T have the honour to be, &c. &e.

* Wittram Hurtoy, Secretary.

* To Robert William Brandling, Esq.”

The Coal Trade Committee immediately adopted the suggestion, and
appointed John Buddle, George Johnson, and Nicholas Wood, Esqrs., to
make the necessary arrangements for collecting the specimens of gas,

Fire-damp from the Coal Mines near Newcastle. 3

drogen, or marsh gas of chemists, which issues in a state of
purity from coal, wholly free from admixture with hydrogen,
carbonic oxide, or olefiant gases, and but rarely containing
a trace of carbonic acid gas*. ‘The sole difference in the ex-
plosive gas of different mines must hence be referred to the
degree of admixture with air. If diluted with nineteen or
twenty times its volume of air, the mixture does not detonate
or take fire at all; on diminishing the proportion of air below
this term the mixture becomes inflammable, and on the ap-
proach of a lighted candle, a pale blue flame appears, which
passes slowly through the mixture when the air is in large
excess; rapidly when the ratio is favourably adjusted for com-
bustion. ‘The most explosive mixture, as Davy correctly
states in his “ Essay on Flamet,” is formed of one measure of
pure fire-damp, and about seven measures of air. Such mix-
ture, unlike an explosive mixture made with air and hydrogen
or carbonic oxide gas, is not kindled by incandescent solid
matter, such as a mass of hot iron; but it burns rashly [rapidly ?]
in contact with flame, and detonates readily with the electric
spark. As the proportion of pure fire-damp rises above a
sixth, the mixture burns less and less readily, and the tint of
the flame changes at the same time from blue to yellow or
brown. ‘The phenomena receive a ready explanation from
the well-known principles established by Davy.

The analysis of fire-damp was performed by detonation
with oxygen gas over mercury. In successful analysis with all
the gases, the diminution in volume subsequent on detona-
tion with the electric spark, and due to gaseous matter con-
densed as water, was precisely twice the volume of carbonic
acid gas which was generated, and equal to the oxygen gas
which disappeared. ‘The volume of carbonic acid gas some-
times fell short of half the diminution due to production of

* Extract of a letter from Majcr Emmett, Royal Engineer, to Mr.
Hutton, dated Hull, 19th February, 1836.

“ T send you the following extracts from a letter from Dr. Dalton of the
13th, As regards Wallsend Pit, they are important, and to me conclusive. I
sent him three bottles Mr. Buddle had collected for me about three months
ago, also one of water from the old working at Gateshead Park Pit, for-
warded to me by Mr. Wood. Respecting the Wallsend gas he says: ¢ I
received your letter and bottles of gas safely, and soon after opened the
bottles under water. ‘The air in each bottle was very much alike. It was
constituted of some two or three per cent. of carbonic acid, about one
tenth common air rather short of oxygen, and the rest, about eighty-five
per cent., was pure carburetted hydrogen, or pond gas, without a trace of
either pure hydrogen or olefiant gas.’ Respecting the Gateshead water
he says, ‘ The bottle of water from the old waste I also examined ; it
contained about one per cent. of soluble nyatter, chiefly common salt, with

some carbonic acid, sulphurous acid, sulphuretted hydrogen and lime,’ ??
(t See Phil, Mag. First Series, vol. xIxvi. p. 448.]

4 The late Dr. Turner’s Chemical Examination of the

water, but this only took place when the combustion was in-
complete. Sometimes the gaseous mixture, after detonation,
was more or less obscured by a deposit of carbonaceous
matter, and in such instances, as already remarked by Dr.
Henry, there is always a deficiency of carbonic acid gas,
which deficiency is less considerable the more completely the
mixture at the moment of detonation approximates to perfect
transparency. I have occasionally observed this cloud, even
when ample oxygen for complete combustion was present;
but with a decided excess of oxygen it generally does not oc-
cur at all, or at most in so slight a degree as not to be appre-
ciable. To show the course of the inquiry, I quote three
analyses, in the first of which an error, from deposited carbon,
is apparent.

I. Analysis of fire-damp from Jarrow Colliery, which issued
Jrom a seam of coal eleven fathoms below the Bensham seam.

Specific gravity as found by weighing the gas = 0°6209.
Tested by nitrous gas it was found in one experiment to con-
tain 2°25 per cent. of oxygen, and in a second 2°] per cent.,
indicating as a mean 2°2 per cent. of oxygen, equivalent to
11 per cent. of air. This gas, which was quite free from car-
bonic acid gas, may be considered as a mixture of 89 mea-
sures of real marsh gas with 11 measures of air. A gas so
constituted, and assuming 0°5595 as the specific gravity of
marsh gas, should have a specific gravity 0°6079 ; for 0°5595
+0°89 + 0°11 = 0°6079. Of this gas 12°3 measures, con-
taining 0°3 of oxygen and 11 of real marsh gas, were fired
with 32°7 measures of a sample of oxygen gas, which con-
tained 31 of real oxygen gas:—

Loss due to condensed water cosesscadessnesssssseece | == 22's
Carbonic acid gas generated and absorbed by
POLASSA coveseccecseccrccscencercsscssccsscssccscssesens == Oh

Residual oxygen, determined by firing with hy-
CrOgen GAS vsscscccsesscscsccvescsevecercsssvcccseess == LOS
Deducting 10°5 + 9:4, the oxygen above ac-
counted for, from 31:3, the whole oxygen gas
originally present, there remain, as Oxygen
gas which went to the production of water .... = 114 —

If. Analysis of a gas from the Bensham coal seam, Jarrow

Colliery, collected from a blower, which caused the accident
in 1826.

Specific gravity actually observed = 0°6381.
This gas was quite free from carbonic acid gas. In two

Fire-damp from the Coal Mines near Newcasile. 5

trials with nitrous gas, it was found to contain 3°7 per cent.
of oxygen, equivalent to 18°5 of air. A gaseous mixture of
18°5 air, and 81°5 real marsh gas, should have a specific
gravity of 0°641, since 0°5595 + 0°815 + O185= OG41.

Of this gas 13°5 measures, inferred from the foregoing
premises to contain 0-5 of oxygen and 11 of real marsh gas,
were fired with 30 measures of oxygen, which contained 28°8
of real oxygen gas.

Loss of volume due to production of water = 22:8
Carbonic acid gas generated .....sesseeereeeee = 112
BEPMAUAL OXY IED b.sanenes Jodekedbe-saveonesiendcas!!) =) [604

Deducting 17°6 from 29°3 there remain, as
Oxygen gas which went to the produc-
Tien ELT WALT! (f A2e Le Sek Pusrdedos Coceteewelessenet hos by

III. Analysis of a gas from the Eppleton Jane Pit, Hutton
Seam, Hetton Colliery, collected at a depth of 175 fathoms
below the surface.

Specific gravity actually observed......... = 0°78.

This gas was quite free from carbonic acid. ‘Two experi-

ments with nitrous gas agreed in indicating the presence of
46 per cent. of oxygen, equivalent to 23 measures of air.
Analysis indicated the presence of 50 per cent. of real marsh
gas, leaving 27 per cent. as nitrogen, independently of that
already considered as atmospheric air.

Of this gas 11 measures, containing 0°5 of oxygen, were

fired with 28 of oxygen gas, which contained 26:9 of real
oxygen.

Loss of volume due to formation of water... = 10°5
Carbonic acid gas generated ....cccccccserseee = 5°5
REAL OLVMEH 20.0. crcostansasstneneweernesdon == 16%
Deducting 5°5 + 16°4 = 21:9 from 27°4 there
remain, as Oxygen gas which went to the
MOVIGAISOM OF WLC .scccccceactecatecdtasccase == 5eg

A gaseous mixture, consisting of 50 measures of real marsh
gas, 23 of air, and 27 of nitrogen, should have a specific
gravity of 0°7724, since 0°5595 +0°5 + 0°23+0°9727 + 0°27
= 0°7724.

The first of the foregoing analyses supplies an instance
where the loss of carbon was decisive. In the second and
third, as in the whole series of successful analyses, the car-
bonic acid gas may be taken as exactly equal to half the con-
densation due to the formation of water, and as containing
half the oxygen which was required for complete combustion.
The quantity of marsh gas present was equal to half the oxy-
gen required for its complete combustion, to half the con-
densation due to generated water, and to the volume of car-

6 Thelute Dr. Turner’s Chemical Examination of the

bonic acid gas which was produced. As this was a uniform
result in all the samples, it is manifest that the constitution
of the inflammable principle of fire-damp is identical with
that of marsh gas or light carburetted hydrogen. The pro-
portions of carbon and hydrogen indicated by analysis, suffi-
ciently demonstrate the absence of such gases as hydrogen,
carbonic oxide, and olefiant gas. Their absence, however,
was proved by other methods. A portion of fire-damp was
mixed in a tube with chlorine of known purity, and the mix-
ture kept for a quarter of an hour in a dark place, when the
chlorine was absorbed by milk of lime; the original quantity
of fire-damp was always recovered, except a slight loss due
to the mere washing to absorb the chlorine. ‘The absence of
olefiant and carbonic oxide gases was also proved by means of
spongy platinum. In 1824, soon after the curious action of
spongy platinum in causing the combination of oxygen and
hydrogen gases was made known by Deebereiner, both Dr.
Henry and myself pointed out the obstacles to that action, oc-
casioned by carbonic oxide, olefiant gas, and some other
gases*. (Philosophical Transactions, and Edinburgh Philoso-
phical Journal for 1824.) And Dr. Henry at the same time
showed that marsh gas differs remarkably in this respect from
carbonic oxide and olefiant gases, as it offers scarcely any
impediment to the action of platinum. Agreeably to those
researches, it follows that, if fire-damp contained merely
marsh gas, oxygen, and nitrogen, spongy platinum introduced
at common temperatures, or even heated to 300° Fahr., would
not produce any sensible effect ; and that if a small quantity
of an explosive mixture + made with one measure of oxygen,
and two measures of hydrogen gases, were added to the fire-
damp, spongy platinum should cause a production of water
corresponding to the quantity of explosive mixture so intro-
duced, without the production of any carbonic acid. But if
carbonic oxide or olefiant gas were present, then cold spongy
platinum would not act at all, a small proportion of explosive
mixture being employed; and if the action were forced by
using hot spongy platinum, or by the free introduction of ex-
plosive mixture, then would carbonic acid as well as water
be generated.

To apply these facts to the case in point, some very active
platinum balls, of the size of peas, were made from a mixture
of pipe-clay, spongy platinum, and the yellow ammoniacal chlo-
ride of platinum, the materials being mixed with water so as

(* Dr. Henry’s paper on this subject, from the Philosophical Trans-
actions, will be found in Phil. Mag. First Series, vol, Ixv. p. 269,—Eprv.

+ By the expression “ explosive mixture,” | hereafter mean a mixture
made with one measure of oxygen and two measures of hydrogen gases.

Fire-damp from the Coal Mines near Newcastle. 7

to form a plastic mass, which, after receiving the required size
and form, was gently dried, and ignited for an instant before
the blow-pipe*, and were introduced into the gaseous mixture
over mercury, sometimes cold and at others warm, ten or twenty
seconds after incandescence. ‘Their action on all the samples
of fire-damp was precisely of the same character with fire-
damp, oxygen being previously added or not; the platinum
balls, whether cold or warm, were completely inactive. On
adding some explosive mixture to the fire-damp, the platinum
balls acted readily to their full extent. To give some in-
stances.—

I. With fire-damp from the yard coal seam, Burraton Col-

liery, the specific gravity of which was 0°600.

With 46:5 measures of this gas, and 12°5 of explosive mix-
ture, a platinum ball, nearly cold, caused in ten minutes a loss
of volume equal to 12 measures.

In a second trial the loss in ten minutes was 13°6 in a mix-
ture of 49 measures of fire-damp, and 141 of explosive mix-
ture.

Il. With fire-damp from the Bensham coal seam, Wallsend
Colliery, the specific gravity of which was 0'6024.

In a mixture made with 34°3 measures of fire-damp, and
13:1 of explosive mixture, a platinum ball introduced warm,
caused in six minutes a loss of volume equal to 124: measures.

With 43°5 measures of the same gas, and 22-9 of explosive
mixture, the loss in eight minutes was 21°7, the platinum ball
being introduced warm.

With 55 measures of the same gas, and 7 of explosive mix-
ture, a cold platinum ball caused a loss of 6°3 in six minutes.

The action was equally rapid with the other gases; nearly
the whole explosive mixture disappearing within the first or se-
cond minutes after the introduction of a platinum ball, whether
warm or cold. In no instance did barytic water, subsequently
admitted, detect in the residue a trace of carbonic acid gas.

When to any specimen of fire-damp hydrogen was added,
the action of platinum always revealed the presence of air.
When the quantity of air was small, the action of platinum
was of course slow; nor did it in that case indicate with fide-
lity the quantity of air present, a portion of oxygen not
uniting with hydrogen. Thus in the fire-damp from the yard
coal seam, Burraton Colliery, nitrous gas indicated the pre-
sence of 6°2 per cent. of air, and platinum only 3:3 per cent.
In the gas from the Bensham Seam, Wallsend Colliery, ni-

* Before use the little balls were always ignited.

8 The late Dr. Turner’s Chemical Examination of the

trous gas indicated the presence of 9 per cent. of air; whereas
platinum detected only 5 per cent. in one trial, 8-5 per cent.
in a second, and 6 per cent. in a third. A certain degree of
impediment to the action of platinum by marsh gas is thus
rendered apparent. But when the fire-damp was freely mixed
with air, then after the hydrogen gas platinum acted freely ;
and I have found under such circumstances the indications
from platinum to coincide with those from nitrous gas. Thus in
fire-damp from the low-main coal seam, Killingworth Colliery,
of specific gravity 08226, platinum and hydrogen indicated
9-4 per cent. of oxygen, equivalent to 46°5 of air; and in two
experiments with nitrous gas precisely the same result was ob-
tained. A ball of platinum may hence be applied to deter-
mine the air in fire-damp, even when its quantity is small, by
first diluting the gas with a known quantity of air, or enliven-
ing the action of the platinum by adding some explosive mix-
ture.

To those chemists who chance to be practically conversant
with the action of platinum on gaseous mixtures, the evidence
above adduced as to the freedom of fire-damp from hydrogen,
carbonic oxide, olefiant gas, sulphuretted hydrogen, and si-
milar inflammable gases, will, I doubt not, be quite satisfactory.
To myself they do not leave the shadow of a doubt on the
question. Those who are not familiar with such researches,
may be warned that, in repeating my experiments, they will
certainly fail of witnessing the same phenomena, unless they
are very scrupulous in having pure gases, and in employ-
ing platinum balls with their full energy. The influence of
platinum on gases is modified by such very slight circum-
stances, that a small matter will cause a ball to be wholly inert
which would otherwise have acted with effect.

In applying nitrous gas to determine the quantity of oxygen
in fire-damp, I employed the method of Dr. Dalton, as de-
scribed in Dr. Henry’s Elements of Chemistry. A measured
quantity of fire-damp was added to the nitrous gas contained
in a graduated tube half an inch wide, and the gases were al-
lowed to act on each other over water, without agitation. The
diminution of volume had attained its maximum in five or six
minutes, and in general much sooner. Of the total loss, 39ths
were taken as oxygen. This method is not in all cases rigidly
correct, but its indications were sufficiently exact for my pur-
pose, controlled as they were by the action of platinum, by the
analysis of the gas by detonation with oxygen, and by the
specific gravity of the gases. Before relying at all on this
method, however, I applied it in the analysis of gaseous mix-
tures containing known quantities of oxygen gas. On ap-

Fire-damp from the Coal Mines near Newcastle. 9

plying it to the analysis of atmospheric air it indicated 20°4
per cent. of oxygen. On agitating the air and nitrous gas,
just after admitting them into the same tube, the diminution in
volume was excessive. In a specimen of nitrogen gas, to
which so much air was admitted that the whole mixture con-
tained 3 per cent. of oxygen, nitrous gas indicated 3°3 per
cent. of oxygen in one experiment, and 3°2 in a second. With
nitrogen, which contained 3°6 per cent. of oxygen, nitrous gas
indicated 4°4 in one trial, and in a second 41 per cent of oxy-
gen. In nitrogen gas, with 4°7 per cent. of oxygen, nitrous
gas indicated 4°7 per cent. in one trial, and 5:2 in a second.
In nitrogen containing 7°3 per cent. of oxygen gas, nitrous
gas indicated 7-4 in the first experiment, and 8°4 in the second.
In the last case a large excess of nitrous gas was employed.
In nitrogen gas in one experiment, and 11°5 in a second*. In
this last case also nitrous gas was used in large excess.

Mines in which the Gas was collected. Specific Gravity.
Observed Calcul.

1. | Bensham Coal Seam, Wallsend Col-
MCT ae tosses donc agedasabaaceaasege= ens 0°6024) 0°5991) 9} 9} o}| oO
2. | Yard Coal Seam, Burraton Colliery | 0°600 | 0:5903} 93 |} 7| o| o
8. | High Main Seam, Killingworth Col-
MET Vis s .aa- ates Scerascante Senasoaroscsece 0°6196) 0°6236) g5 8 7 (0)
4. | Low Main Seam, Killingworth Col-
MEN Yan aeaanedasclen tease deite cep ee neeeden- 0°8226) 0°8325) 37 | 46°5| 16°5| O
5. | Marquis of Londonderry’s Pensher
Colliery, from the Hutton Seam
Waste, 125 fathoms deep ......... 0°966 |0°9662) 7 | 82] 11 (0)
6. | Marquis of Londonderry’s Pittington
Colliery, Adelaide Pit, Hutton
Seam,45 fathoms below the surface] 0866 | 0°8755| 98 |67°5| 4:5 | O
7. | Eppleton Jane Pit,;Hutton Seam,
Hetton Colliery, 175 fathoms be-
Nowy thersurace, casscosavcsctensonshs 0°747 |0°7677| 50 6 | 44 0)
8. | Blossom Pit Main Coal Seam, Het-
ton Colliery, 100 fathoms below
CHOLSMTLAC Cr cores. cope rae ecvtsaspccneas 0°78 |0°7724| 50 | 23 | 27| oO
9. | Bensham Coal Seam, Jarrow Colliery] 0°6381| 0°641 |81-5/18°5| O|}| O
10. | Jarrow Colliery Seam, 11 fathoms
Delo ws Yess ei's.dedeescstbee des 0°6209| 0°6079} 89 | 11 0 10)
11. | Bensham Seam, Willington Colliery,
145 fathoms from the surface _...| 0°7278/ 0°7175] 68 |28-7| O | 3:3
12. Ie il 0 100} O

In these experiments the error is very uniformly such, that
more oxygen was indicated than was actually present. The
causes of error appear to be especially twofold,—agitation,
and a large excess of nitrous gas. By permitting the action
to ensue tranquilly, and avoiding much excess from nitrous
gas, the indications in my trials were uniform, and very nearly
true. Applying the same method to fire-damp, I found that

[* There appears to be some omission here. Enrr, Puri. Mac.]

10 Col. R. Wright’s Meteorological Observations made

in two or more trials with the same gas the indications hardly
ever differed so much as 1 per cent. of oxygen; and in gene-
ral, as in several instances already given, the coincidence in
different experiments was exact, Having now mentioned all
that appears necessary to elucidate the chemical nature of the
different samples of fire-damp from the mines of Newcastle, I
conclude this account of the examination by inserting a tabular
view of the composition of all the gases which have been ana-
lysed. [See Table in preceding page. |

The gas, No. 12, proved to be unmixed air. I have no
remarks to offer respecting the nitrogen found in some sam-
ples of the fire-damp beyond what will readily occur to other
chemists, who, I apprehend, will consider, its presence as a
simple consequence of oxidizing processes, especially of me-
tallic sulphurets, abstracting oxygen from atmospheric air.

II. Meteorological Observations during a Residence in Co-
lombia between the Years 1820 and 1830. By Colonel
Ricuarp Wrisut, Governor of the Province of Loxa,
Confidential Agent of the Republic of the Equator, §c,
Sc.

[* the materials of science could be gathered only by the
scientific, the following collection of observations would
be a useless labour; but it frequently happens that, in distant
countries, the opportunity of observing natural phenomena
falls to the lot of those very ill fitted in most respects to profit
by it. The genius of a Humboldt, like an incantation of
science, descends upon the New World but once in a series
of ages. The most that can be done by an ordinary observer
is to offer his mite,—a single stone towards the pyramid of
knowledge,—in the hope that he may casually prove useful ;
and with such humble pretensions can scarcely be deemed
importunate. Should even this apology barely extenuate the
sterility of a ten years’ residence in a country so admirably
varied and rich in natural phenomena as Colombia, something
further may be urged in excuse of the military traveller, obliged
frequently to hurry through the most interesting parts, and to
vegetate whole years in others of minor importance; without
books, without instruments, without resources; fettered too
often by the chain of his own daily wants and sufferings; and
fallen on a time when every species of local and traditional
information, every glimmering of philosophic research had
been buried and obliterated amid the storms and struggles of
the revolution,

The geographical features of Colombia have been por-

in Colombia between the Years 1820 and 1830. 11

trayed by Humboldt with an accuracy which renders further
description superfluous. It is, however, impossible to traverse
this extensive territory without being struck by the physical
phenomena of a country where height produces the effect of
latitude, and where the changes of climate, with all the con-
sequent revolutions of animal and vegetable life, are brought
about by localities to which we find little analogy in Europe.
The equatorial seasons, as is well known, are merely the wet
and dry; and though the Spaniards, influenced by European
recollections, have given the former the name of winter invi-
erno, it is during this period that nature revives from the vege-
tative torpor which the scorching tropical heats produce in the
low-lands in almost an equal degree with the frosts of northern
climates. In the vast plains which extend to the south and
east of the great chain of the Andes the rainy season observes
an invariable order. The Orinoco begins to rise in April, and
attains its maximum of increase in July and August, when the
immense sayanas which extend to the base of the Andes
are converted into the appearance of an inland ocean. It de-
creases from this period, and the summer is reckoned from
October to April. In the mountains, on the contrary, the
rains commence about the former month, and predominate,
with intervals of fair weather, till May or June. The winter
of the low lands, to the west and north of the Cordillera, both
on the Pacific and Atlantic coasts, is governed by that of the
mountains, but with several curious localities. Thus, the
rainy season of Guayaquil is nearly as regular as that of the
plains, being reckoned from the middle of December to the
middle of May; while the thick forests, which further to the
north cover the provinces of Esmeraldas, Barbacoas, and
Choco, produce, by their constant evaporation, an almost per-
petual deluge, Wherever, on the contrary, the Cordillera
recedes to some distance from the coast, as is the case with
parts of the Venezuelan chain, the intermediate country is
parched by a drought often of several years. Maracaybo, and
a considerable part of the province of Coro, are instances
where sandy plains, scantily shaded by Mimosas and thick
plants, afford shelter and subsistence only to flocks of goats
and asses. The coast of Rio Hacha is equally dry and ste-
rile, till it approaches the foot of the isolated ridge of Santa
Marta; while the Goagira territory, situated betwixt Rio
Hacha-and Maracaybo, is regularly inundated every year,
and consequently, though destitute of streams, maintains con-
siderable herds of cattle and horses; a circumstance to be
ascribed to the vicinity of the Ocana branch of the Andes,
which extends, with its clouds and thick forests, almost to

12 Col. R. Wright’s Meteorological Observations made

the confines of this province. The whole Peruvian coast from
Payta to Lima is an additional instance of the same fact, where
the recession of the Andes from the coast is marked by sandy
deserts which the industry of the Incas had rendered product-
ive by artificial irrigation. In the valleys and on the table-
lands of the mountains themselves the culminating summits
produce great variations in the distribution of moisture. The
city of Caraccas, situated at the foot of the Silla, has the be-
nefit of a regular though mild rainy season, while within a
league there are spots which suffer several years of drought.
Popayan, placed at the head of the sultry valley of the Cauca,
and surrounded by lofty paramos, has nine months of con-
tinued rains and tempests, attributable to the clouds which
are driven in opposite directions from the mountains till they
encounter the hot ascending air of the valley. In the ancient
kingdom of Quito, now called the Republic of the Equator,
the mass of Chimborazo interrupts the passage of the clouds
“from south to north; so that, while the western slopes are de-
luged with rain, the elevated plains of Riobamba to the east
recall to the imagination of the traveller the deserts of Arabia
Petreea. Following the same mountain chain towards the
city of Quito, we observe the storms arrested betwixt Coto-
paxi and Pichincha, over the valley of Chillo; while two
leagues further to the north the climate of the village of Po-
masqui is so dry as to have given it the name of Piurita (little
Piura).

The manner in which rain is formed and precipitated at
various elevations, seems to illustrate and confirm the theory
of Leslie. In the region of paramos, i.e. from 12,000 feet
upwards, the encountering aérial currents, unless in the case
of some strong agitation of the mass of surrounding atmo-
sphere, are of a low and nearly equal temperature. ‘The rains
in consequence assume the form of thick drizzling mists, known
by the name of paramitos. On the elevated plains we find
the showers more or less sudden and violent, according to lo-
calities which give rise to a mixture of currents more or less
variably heated. Quito, for example, is situated on what may
be called a ledge of the lofty mountain of Pichincha, and
overlooks the valley of Chillo or Guaillapamba, furrowing the
adjacent table land, on which the thermometer often rises to
80° in the shade. The encounter of portions of the atmo-
sphere, thus variously heated, produces showers as sudden
and heavy as those which generally distinguish tropical cli-
mates. On the slopes of the Cordillera the rains are generally
violent for the same reason. Looking to the hygrometrical
state of the atmosphere, as it results from observations made

zn Colombia between the Years 1820 and 1830. 13

on the table lands of the equator and the coast of the Pacific,
we find it to vary from 0° in the damp forests of Esmeraldas
to 97°'1 on the elevated plain of Cayambe; the experiments
in both places being made during June and July, the summer
months both of the coast and mountains. The average me-
dium for the low lands is 23°°85; for the Cordillera 44°36 of
the hygrometer constructed upon Leslie’s principle; but we
are in want of sufficient data for those elevations which ap-
proach to the limit of perpetual snow. ‘To judge, however,
from a small number of observations made on the mountain
of Cayambe at 12,705 and 14,217 feet of elevation, and at
the hut of Antisana at 14,520 feet, where the hygrometer
was found to give 16°°5, 13°°9, and 303, it would not seem
that the dryness of the atmosphere increases in ratio of the
elevation ; at least in the neighbourhood of snowy mountains,
where a continual moisture is exhaled, and heavy mists sweep
over the soil towards evenings even of the fairest days. :

To estimate the general distribution of temperatures through
the vast territory of Colombia, we may conveniently consider
it as divided into five zones. 1st, That of the level, or nearly
so, of the ocean. 2nd, That of the small elevations, from 500
to 1500 feet. 3rd, That of the slopes of the Cordillera, from
2000 to 7000 feet. 4th, That of the elevated plains, or table
lands, from 8000 to 10,000 feet; and 5th, That of the para-
mos, from 11,000 feet to the limit of perpetual snow.

1. The degree of heat at or near the level of the ocean is
modified by a variety of local cireumstances, which may be
ranged under the following heads: proximity of the sea; of
great rivers or lakes; of lofty ridges of mountains; of exten-
sive forests; of contiguous elevations which impede the circu-
lation of air, and produce reflected heat. The various com-
binations of these circumstances may be considered as afford-
ing a rule of the increase or diminution of temperature. Thus,
La Guayra, situated on a sandy beach backed by a perpen-
dicular wall of rocks, has no counterpoise to the excess of
heat but the sea breeze, and the remote influence of the ridge
of the Silla, which nowhere reaches the limit of perpetual
snow. Humboldt considers it in consequence as the hottest
place on the shores of the New World (Personal Narrative,
vol. iii. p. 386.), the mean annual temperature being $2°6;
yet the observations I made during some months’ residence
in Madracaybo give an annual mean of 84°63. Nor is this
surprising, when we consider the localities of both places. In
Maracaybo the sun’s rays are reflected from a barren sandy
soil, scantily sprinkled with Mzmosas and prickly plants. The
mountain chains are too remote to have any influence on the

14 Col. R. Wright’s Meteorological Observations made

atmosphere, so that several years frequently pass without any
regular fall of rain. The vicinity of the lake, no doubt, acts
slightly as a refrigerant; but the city is built on the border of
its outlet to the sea, where it is both narrowest and shallowest,
and is consequently heated nearly to the temperature of the
incumbent atmosphere. Add to this, the small sandy eleva-
tions to the north, which intercept the partial effect of the sea-
breezes, so that they are scarcely felt, except in the months of
December and January, when the thermometer sometimessinks
to 73°; yet the medium even of these two months is not less than
81°; while that of La Guayra from November to December at
noon, is, according to Humboldt, 75°°8, and at night 70°9.
(Personal Narrative, vol. iii. p. 387.) Rio Hacha is situated
on asandy beach; the sea-breeze blows with such violence that
boats can scarcely land between ten in the morning and four
in the afternoon. These winds, however, sweeping over the
hot plains of Coro and Maracaybo, have but a partial effect
in lowering the temperature, the annual mean of which is 1°-98
less than that of Maracaybo. I never saw the thermometer
lower than 75°, nor above 89°. In Santa Marta the average
of the coolest months is 82°25. The thermometer, however,
never rose during my residence there above 87°. The soil is
sandy, and the city is surrounded by bare rocky heights to the
north and south, which counterpoise the cooling influence of
the Sierra nevada (snowy mountains), from which it is but a
few leagues distant. ‘The temperature of Barranquilla, a vil-
lage situated on the river Magdalena, about eighteen miles from
its mouth, is nearly the same with that of Santa Marta; for if,
on the one hand, the air is refreshed by the evaporation from
a damp soil covered with luxuriant forests and the vicinity of
a large river, on the other, it is beyond the reach of the sea-
breeze, and the influence of the mountains which operate in
Santa Marta. ‘The annual mean is 82°20, ‘That of Cumana
is, according to Humboldt, 81°. The breezes which sweep
from the gulfof Paria over the wooded Brigantine chain pro-
bably contribute to lower the temperature.

We have thus, on a calculation of six points on the Atlantic
coast of Colombia, a mean annual temperature of 82°°56*.
The shores of the Pacific, as far as the latitude of Payta, are
subjected to other influences, being almost entirely covered by
damp luxuriant forests; while the ocean itself is cooled, as
Humboidt observes, by the winds which blow continually

« I have not included Cartagena, because the number of observations
is perhaps too limited to draw a conclusion as to the yearly temperature.
If we take them into the calculation, the annual mean would be 82°86,
which is probably too high,

in Colombia between the Years 1820 and 1830. 15

from the south. This, however, is more perceptibly the case
from latitude 8° to 13°, where the air is cooled to an average
of 71°8. (Humboldt De Distributione Geog. Pl. p.92). Be-
twixt 9° N. lat. and 3° S. lat., if we may trust to observations
made at the five points of Panama, Esmeraldas, El Morro,
the island of Puna, and Guayaquil, the annual mean is 80°11,
being 2°-45 less than the mean of the Atlantic coast. A no-
table difference also arises from the superior elevation of the
Pacific chain of the Andes, and its more immediate vicinity to
the coast, while the Venezuelan branch, with the exception of
the Santa Marta ridge, is both lower and more inland. A
curious exception to the general temperature of the Pacific
coast may be found on passing Punta Galera and Cabo San
Francisco (lat. 50’ N.) to the south. The sky is here almost
perpetually clouded, and a drizzling rain falls through the
greater part of the year. During a week I passed there I
never saw the sun; and the average temperature was only
74°14, This was the more striking, as along the coast, im-
mediately to the north of Punta Galera, the weather was con-
stantly dry and the sky clear. ‘The miry state of the road
across the point of the Cape of San Francisco indicates the
line of separation betwixt two distinct climates. It will be
seen by the map, that from P. Galera the coast, after run-
ning nearly due west, turns abruptly to the south.

2. On penetrating into the interior of the country, and ex-
amining the temperature of small elevations, we may take, as
forming an aggregate specimen of the whole country: 1. The
damp wooded valleys of the Orinoco and Magdalena; 2. The
forests which border on the Pacific; and 3. The immense
plains of Venezuela, alternately flooded and parched with ex-
cessive heat. Humboldt assigns to the valley of the Orinoco
a mean temperature of 78°2. ‘The small number of observa-
tions I have made on that of the Magdalena would give a
mean of nearly 83°, which I should scarcely think too high,
considering the localities of the river, which, flowing from
south to north, affords no channel to the sea-breezes. Its
mass of water is also much less considerable than that of the
Orinoco; while its numerous sinuosities, and the low ridges
which border it in the upper part of its course, contribute to
render the air stagnant and suffocating. The temperature of
Honda, at 1200 feet of elevation, is as high as that of any part
of the coast, except Maracaybo. The unbroken forests which
extend from the roots of the Quitenian Andes to the shores of
the Pacific have a much lower temperature, caused by the
proximity of the snow-capped Cordillera, and the humidity
which prevails throughout the year. Accurate observations

16 Col. R. Wright’s Meteorological Observations made

give an annual mean of 76°78, or 1°°42 lower than the valley
of the Orinoco, and 6°22 lower than that of the Magdalena.
The mean temperature of the plains of Venezuela is reckoned
by Humboldt at 88°4 (De Distributione Geog. Plant. p. 92.);
yet several reasons may induce the belief that this calculation
is excessive. This illustrious traveller performed his journey
during the summer season, when the atmosphere is heated by
the reverberations from a parched and naked soil. Persons
who have resided near the Apure, state the climate in rainy
weather to be cool, and refreshed by a constant breeze. It is
only on the coast of the Pacific that the rainy season is the
period of the greatest heat, when the air is still, and undisturbed
by those electric explosions so common on the mountains and
in the interior. The observations I made at Varinas and San
Carlos, towards the beginning of the winter season, give a
mean of 81°; and averaging the dry season at 88°4, we have
a yearly mean of 84°°7, which is probably the extreme, or
something beyond it. ‘There is no doubt it is in the plains of
the interior we find the greatest heat during the dry season.
In the level country, called the valley of Upar, betwixt the
mountain ridges of Santa Marta and Ocaia, I found the ther-
mometer in the shade several times above 100°, and once as
high as 108°. The average of nineteen observations made at
different points of this district is 89°°9; but we must allow a
considerable decrease during the months when the soil is co-
vered with thick vegetation, and drenched by continual rains.
As a general mean of the interior, at small elevations, we may
take 86°°67, or nearly that of Cumana.

3. The temperate mountain region lies nearly betwixt the
elevations of 3000 and 7000 feet. Below this may be consi-
dered as a hot climate, such, for instance, as Valencia and the
valleys of Aragua in Venezuela, the height of which is from
1500 to 2000 feet, and its mean temperature 78°, or 0°:24 above
that of Guayaquil on the Pacific; but the soil, stripped by
cultivation of its ancient forests, imbibes freely the solar-rays,
which are besides reflected from the rocky elevations which
everywhere surround the cultivated districts. The tempera-
ture of Caracas (elevation 2904 feet) was fixed by Humboldt
in his Essay De Distributione Geographica Plantarum, p. 98,
at 69°°6; but in his Personal Narrative, b. iv. c. xii. p. 460,
he considers 17°2 of Reaumur = 70°40 of Fahrenheit, nearly
as the true yearly mean. My own observations during a re-
sidence of some months give 71°40. The preference would
be certainly due to Humboldt’s caiculation, but for some col-
lateral circumstances deserving attention. I heard it generally
remarked in the city, that the seasons had grown hotter since

in Colombia between the Years 1820 and 1830. 17

the earthquake of 1812. It would be difficult to explain how
the temporary evolution of volcanic gases, supposing such to
have taken place, could operate any permanent change on the
surrounding atmosphere; yet other causes may have produced
an effect falsely ascribed to the phenomenon most impressed
on the imagination of the inhabitants. On looking over Hum-
boldt’s collection of observations for December and January,
1799, we find the thermometer seldom rise to 75°, and often
sink to 59°; so that the mean of these months is about 68°.
During the same months in 1821, the daily range was from
65° to 76°. I never observed it lower than 61°°5, and on one
occasion, at 5 a.m., it stood at 61°°0. The mean of these two
months is 70°°21, or 2°21 higher than the estimate of Hum-
boldt. The clearness and beauty of the sky, during almost
the whole period of my residence, is also a circumstance op-
posed to Humboldt’s “ calum sepe nubibus grave que post solis
occasum terre appropinquant.”—De Distributione Geog. Plant.
p. 98. I remember but once to have seen a fog in the streets
of the city. Future observations will show whether any change
of climate has really taken place, or whether the differences
observed be only such variations as may be frequently re-
marked in the same place betwixt one year and another. The
mean of the whole temperate mountain region may be reckoned
at 67°°80; that is, if we limit ourselves to the districts partially
cultivated and inhabited. ‘The declivities of the Andes, still
covered with vast and humid forests, have probably their tem-
perature proportionably lowered. Thus the village of Mindo,
on the western declivity of Pichincha, embosomed in humid
forests, at 3932 feet of elevation, has a medium temperature
of 65°°5, the same with that of Popayan.

4. The elevated plains of the Andes, betwixt 8000 and
11,000 feet, on which were anciently united the most power~
ful and civilized indigenous nations beneath the dominion of
the Zipas of Tunja and Bogota and the Incas of Quito, and
where the great mass of Indian population is still to be found,
have a general medium temperature of 59°:37, modified how-
ever by local circumstances, and particularly by the proximity
of the Nevados. Thus the village of Guaranda, placed at the
base of Chimborazo, though nearly 500 feet less elevated, is
at least one degree colder than the city of Quito, sheltered
on all sides by the ramifications of Pichincha. ‘The city
again is above one degree warmer than its suburbs on the
plains of Afiaguito and Turupamba to the north and south.
Riobamba is about 200 feet below Quito; yet its situation on
an open plain, bordered by the snowy mountains of Chim-
borazo, Tunguragua, and La Candelaria, renders the climate

Phil. Mag. 8. 3. Vol. 14, No. 85. Jan. 1839. C

18 Col. Wright’s Meteorological Observations in Colombia.

colder and more variable; while the town of Hambato, only
800 feet lower than Quito, but built in a nook of the river
which runs near it, and shut in by dry sandy elevations, has
a climate about 2°°O warmer; so that sugar-cane is cultivated
in its immediate vicinity. The general uniformity of tempera-
ture, which spreads a certain monotony over tropical regions,
is joined, at great elevations, to a daily variability which must
exercise a considerable influence both on vegetable and ani-
mal life. The thermometer, which often sinks at night to 44°,
rises, in the sun, wherever there is a reflected heat, frequently
to 120°, being equal to the heat of Jamaica; while, in the
shade, it seldom exceeds 65°; so that, on passing from shade
to sunshine, one is immediately exposed to a difference of
above 50°, and, in the course of twenty-four hours, to nearly
so°. The shade, in consequence, even on the hottest days,
imparts a feeling of chilliness; while the solar rays seem to
scorch like the vapour of a heated oven. The same difference
is perceptible on the paramos. At the foot of the Nevado of
Santa Marta I observed the thermometer at 5 a.m. sink to
22°; at 9 a.m. it rose to 73° in the sun. On the height of
Pichan, betwixt Quito and Esmeraldas, elevation 12,986 feet,
the thermometer stood at 53° in the shade, and 83° in the sun.
On Antisana, the difference was 22° at the same time, but 34°
betwixt 6 a.m. and 3 p.m. When the atmosphere is calm it
is much more considerable.

5. Although at great elevations, i.e. from 12,000 to 16,000
feet, it is difficult to form a series of meteorological observations,
such is the yearly equality of the temperature, that a single
day may be safely taken as a sample of the whole year; nay,
more, a collection of observations made at similar heights,
though in different places, will give a similar result to a series
taken on the same spot. ‘Thus in the following table there is
little difference betwixt the result of eight observations made
on seven different mountains, and the six made on that of
Antisana.

1. | Paramo of Santa Marta....| 15,000 ft. | 22° 54 a.m.

2. | Paramo of Cayambe ...... 12,705 SiO, oe

3. | Paramo of El Altar ...... 12,986 had oie.

4. | Mine of Condorasto ...... 14,496 45°O0 192

5. | Volcano of Pichincha ....} 15,705 46°°0 1 P.M.

G. | Mountain of Atacaso...... 14,820 41 Ow iti gy

7. | Nevado of Cayambe ...... 14,217 43°0 1} ,,

8. | Paramo of Antisana ...... 14,520 38°°58 6 obser-
vations.

General mean Lexis 39°

[To be continued]

[ 19]
III. On Analytic Crystals. By OH. F. Tarot, Esg.*
{Illustrated by Plates I. II. & III.]

N the course of experiments which I made with my po-

larizing microscope, I discovered a class of crystals which
produce phenomena of great beauty, but of a nature very
different from any that have been before described; for which
reason a new name is necessary for them, and I have pro-
posed that of Analytic Crystals.

I have given a brief description of them in the Philosophi-
cal Transactions for 1837 (page 32). But as I am well aware
of the truth of the Horatian maxim,

* Segniiis irritant animos demissa per aures
Quam que sunt oculis subjecta fidelibus ......
I have here placed before the eye of the reader some coloured
figures in illustration of the subject.

The usual method of displaying colours in crystalline
bodies, consists in placing them between two tourmalines,
called the polarizer and the analyser.

Instead of tourmalines the reflexion from plates of glass
may be used; but whatever form of instrument is employed,
it is necessary to have two of them. Each of these must be
capable of polarizing common light. If not, it will not serve
the intended purpose. A plate of sulphate of lime, for in«
stance, placed vertically to the eye, will not answer either as
a polarizer or an analyser.

The colours displayed by crystals thus placed between two
tourmalines are well known to be very complex and numerous.
‘The greatest variety of tints is often seen in the field of view
at once.

Now, the crystals to which my present paper refers differ
from the ordinary ones chiefly in two remarkable particulars.

(1.) They display, in the arrangement which I shall after-
wards describe, two colours only at any given time. These
colours are complementary to each other, and consequently
in the strongest possible contrast.

(2.) The polarizing plate is employed alone, or in conjunc-
tion with a plate of sulphate of lime. dnd no analysing plate
is required.

From which it will readily appear how differently charac-
terized these phzenomena are from the ordinary appearances
of polarized light, although equally beautiful as micro-
scopic objects.

These results may be obtained with great facility in the fol-
lowing manner :

* Communicated by the Author.

{+ See Lond, and Edinb. Phil, es vol, ix. p. 288 ; vol. x. p, 218,]

'g

9

20 Mr. Talbot on Analytic Crystals.

Dissolve boracic acid in boiling water, and put a drop of
the solution between two plates of glass. It will immediately
crystallize in irregular forms (Plate I. upper figure.).

Place it on the stage of the polarizing microscope using the
polarizer only, and no analyser.

It will then be seen that these crystals (which are floating
in water) present themselves under two aspects, according to
the direction in which they lie. ‘Those which lie one way ap-
pear with all their outlines strongly defined and extremely
dark. Those which lie the other way (or vertically to the
first) appear on the contrary as faint as possible. In our
plate it was necessary to represent them as tolerably distinct,
but in fact it often happens that their faintness is so extreme
that they cease to be visible. This circumstance affords an
example of one of the most curious things in optical science :
for if one of the crystals has been carefully placed in this
position, and a person be then desired to look into the micro-
scope, he will confidently assert that there is no object in the
field of view. If then the polarization of the light be reversed
by turning the polarizer round 90°, the crystal will appear to
start into existence, and become not only as dark as those
represented in the figure, but even darker, or perhaps en-
tirely opake.

Without entering into the theory of the matter here, it
appears to me to result from this, that, of the two refractive
indices of boracic acid thus prepared, one is the same with the
refractive index of water.

If now, the appearance of things being as is represented in
the upper figure of Plate I., we introduce a lamina of sulphate
of lime below the crystals, the appearance changes to that re-
presented in the lower figure.

If we turn the polarizer 90° round, the red crystals become
green, and vice versd.

It is to be observed, that the outlines only are coloured; the
central parts of the crystals are generally white.

This coloration of the outlines constitutes the great beauty
of some of these experiments. Its delicacy however is such
as scarcely to admit of being successfully represented.

The upper figure in Plate II. represents another specimen
of the same crystal, different in shape only. If now we ex-
change the lamina of sulphate of lime for one of different
thickness, the colours change, as shown in the lower figure of
the same plate.

Besides the boracic acid, I find the nitrates of potash and
soda have this property in a high degree. No doubt the list
may be considerably augmented ; yet I think that the crystals

Zé 2.

aie

On the Light received from the Heavenly Bodies. 21

which are destitute of this property are much more numerous
than those which possess it.

I believe, that as a distinctive character this optical pro-
perty may be of great service in chemistry, For instance,
suppose that an exceedingly minute fragment of crystal (con-
sidered to be nitre) were under examination. Let it be viewed
by polarized light in a manner analogous to what is above de-
scribed: then if, when turned in various positions, it fails to
develope two opposite colours, it follows that it cannot be a
particle of nitre. I conceive that this mode of examination
(when properly limited by experience) will prove a valuable
auxiliary to the others already known.

Plate III. exhibits the phenomena produced by the capil-
lary crystals of another salt—the oxalate of potash and chro-
mium. The two figures represent the same object: the change
of colour is effected by reversing the polarization of the light.
It will be understood that the same change takes place by
turning the olyect round 90°. From which it will be readily
seen to follow, that if a complete circle were formed of these
capillary crystals (all radiating from a point) two opposite
quadrants of it would appear green, and the other two red.
The crystallization of this salt is remarkably elegant, but I
have been obliged to confine myself in the plate to the repre-
sentation of one of its simplest forms, owing to the difficulty
of doing justice to those which are more complicated. I have
described it elsewhere*.

Concerning the theory of these very pretty phenomena,
I need say nothing in the present place, because I think that
I have given a satisfactory explanation, in the Philosophical
Transactions, of the cause from whence they originate.

IV. On certain Conditions under which Light is received
from the Heavenly Bodies, and on the Importance of investi-
gating them.

To the Editors of the Philosophical Magazine and Journal.

GENTLEMEN,
iT PRESUME upon your readiness to afford every facility

to suggestions on scientific subjects, in sending you the
few following remarks relating to a point connected with
optical philosophy, which seems to deserve some considera-
tion. Whether it really do contain anything worth further
inquiry will be best ascertained by publicity among your
readers.

* Phil. Trans. 1837, p. 33. [See L. & E. Phil. Mag., vol. x. p. 219.]

22 On certain Conditions under which

It has often struck me that there is a circumstance, appa-
rently of moment, affecting the light imparted to us by the
heavenly bodies, which is neglected by all inquirers, and of
which, so far as I am aware, no sufficient notice has yet
been taken. It is usual to reason as if the whole light sup-
plied by each of those bodies were given out under the same
identical conditions, as if from a mathematical point or centre ;
though a very little reflection must convince us that this is
far from being either strictly, or even practically, the case ; and
the circumstance, therefore, to which I allude is the actual
form and dimensions of those luminaries, conspiring to pro-
duce results, which, although they may be difficult at first
sight to point out and explain, can scarcely be without their
influence on some of the phznomena exhibited by that great
natural agent.

It is obvious that, whatever theory be true with respect to
the constitution of light, whether the Newtonian, the undula-
tory, or any other, the rays which reach us from a luminous
body are propagated by a very complicated process from all
parts of its surface; and although in straight lines always,
yet in al] directions outwards from each point in that surface.
It is difficult for the mind to form any conception of the in-
finitely intricate system of radiation which is thus set in action.
The instance so often given to illustrate the theory of undu-
lations, of a stone dropped into a pool of water, is wholly in-
adequate to represent it. If a perfect sphere were allowed
to fall into a fluid perfectly at rest, the wave caused by its dis-
placement of the fluid would be impelled by a force acting
simply in straight lines perpendicular to the surface of the
sphere, in the plane of its horizontal great circle, which would
be that of its maximum displacement; and therefore the force
by which the wave would be driven upon any given point
could only be exerted in a straight line joining that point and
the centre of the sphere. If this were the case with the wave
of light, the eye would see that point alone of the radiating
surface through which sucha line would pass; and as it does,
in fact, receive the impression of light from every point upon
it from whence a straight line can be drawn to the eye, it
follows that the motion of light (whatever be its nature) is
propagated by a system of infinite divergence at every con-
ceivable angle from every portion of that surface.

If we now look at the bearing of these considerations upon
the point to which we alluded at the outset, we must remark
that the heavenly bodies are for the most part spheres, or
spheroids, of enormous size; and under the small! angle at
which we view them we may be said to receive light from one

Light is received from the Heavenly Bodies. 23

entire hemispherical surface at the same time. There must
be some one spot in it so strictly and accurately opposite to
the eye, that the straight line joining them, that is the course
of the ray from thence, must be truly perpendicular to the
surface of the hemisphere. But on every side of that point
such lines must recede through all angular gradations, until
at the utmost limits of the visible surface they become tan-
gents to the sphere. In the course of this gradation, how-
ever, the rays are propagated, not merely at different angles,
but at increasing distances; so that a ray leaving the circum-
ference of the visible surface must have a considerably further
space to traverse than one from its central point. We will
apply ourselves to that body from whence we derive almost
all our light, and consider for a moment what must be the
result in the case of the sun. That luminary, whatever may
be its substance, is a body of enormous size, having a diame-
ter which, although the measurements may vary in a slight
degree, must be somewhere about 800,000 miles, so that the
difference of distance between that traversed by a ray from
the nearest and from one of the extreme points of the visible
hemisphere, must be about. 400,000 miles, the length of its
semidiameter. Now we know that light travels at the rate of
about 192,000 miles in a second; and it follows that a ray
from the circumference of the hemisphere must have received
its impulse ‘more than two seconds earlier than one from the
superficial centre, in order that they may reach the eye at
the same time.

it is difficult to suppose that so considerable a difference
both in space and time should not exert a certain influence
on some of the phenomena of light within our observation.
In the first place, it is clear that the aberration, which is such
as to be a matter of necessary correction in observations from
this planet of the other heavenly bodies, must be greater by
this difference in the one case than in the other; and the ap-
parent place of the outer edge of the luminous hemisphere of
any one of them must be erroneous in proportion, as com-
pared with that of its superficial centre. In the next place,
since it appears that, as light requires time for its propaga-
tion, there must be some actual mofzon involved in its passage
from one point to another, be its constitution what it may, it
is not unreasonable to suppose that the ultimate motion may
be somewhat more feeble in the case of the greater distance;
notwithstanding the extreme tenuity of its matter, which offers
to bodies moving through it no sensible resistance. That
light does lose strength as it becomes further removed from
its source, is unquestionable; but this is for the. most part an

D4 On certain Conditions under which

effect due to diffusion and absorption. Yet as, in order to
require time for its propagation, it must pass progressively
from point to point throughout the whole course of its journey,
it seems clear that it must consist of, or involve, matter in
some form, however subtile and ethereal; and the analogy
of all fluids would warrant the conclusion that there must be
an actual loss of force when the moving power becomes
more remote. If this be so, a ray of sun-light must consist
of a series of rays between certain limits differing in their
powers, and possibly in their properties; for when we consider
the intimate dependence of the refraction of light, for in-
stance, upon the density of the media through which it has to
pass, and of its several forms of polarity upon the physical
composition of the substances which produce it, who can say
that these phenomena are beyond the reach of such a source
of influence? We know so little of the mysteries of polari-
zation, so little beyond its outward and visible effects, that it
is impossible to conclude that it has no relation to such a cir-
cumstance ; and although in both the above branches of op-
tical inquiry I am well aware that much might be answered
in respect of observations upon light from sources where no
such cause of influence could exist, still so far as they have
been made without a view to this particular point, they do not
amount to a demonstration that in no case could any differ-
ence arising from it be detected.

There is another point which deserves consideration. Al-
though the diameter of the sun subtends a sensible angle at
the eye, still the distance is so great, and consequently that
angle is so small, that we may assume the rays, even from its
extremities, to be parallel, for the purpose of general reason-
ing. In that case it is evident that the series of increased
distances to be traversed by them will be represented by the
versed sines of the angles whereby they are removed from the
centre of the visible hemispherical surface. Now if we sup-
pose undulations or vibrations of any kind as the cause of the
sensation of light, a supposition to which we are led by many
optical facts, it is obvious, that while, in this series, there is a
certain number of points which correspond exactly to those
of the departure of successive waves, there must be also an
intermediate number which would tend to neutralize the first,
and to produce the well-known effect termed interference.
Indeed, the series of points of propagation being unbroken
over the whole curved surface, and mathematically continuous,
it is difficult to conceive, upon the-hypothesis of successive
waves, how this effect can fail to take place, so immediately
and absolutely, without an interval between one and another,

>. eee

Light is received from the Heavenly Bodies. 25

as to admit of the formation of a wave at all. It appears to
constitute another difficulty in the way of that theory. Ac-
cording to the law of curvature, however, which must regulate
the above series, there must of course be many more in-
tervening rays between the points corresponding with the
breadth of a wave in one part of the curve than in the other.
There must be many more in that part where the versed sine
increases least rapidly, near the superficial centre of the hemi-
sphere, than where it increases most so, near its circumfe-
rence; and therefore whatever effects may be due to such a
cause must vary also according to the points from whence any
given waves proceed. If any such interference does take place,
is it not possible that it may have some connexion with those
fixed dark lines which are so remarkable in the spectra of the
sun, and of other heavenly luminaries* ? The light of a lamp
is asserted to display no such lines, though there is some in-
equality of brightness in its spectrum, which may be due to
the unequal composition of the flame*. But if it appear that
there must be some effects produced, and such as are likely
to be in any degree sensible, there is room enough for specu-
lation and inquiry.

I would notice one more point still. The rays proceeding
from the extreme edge of a luminous hemisphere, and those
near it, approximating almost infinitely to the position of a
tangent, must, for some time after their first emission, pass
at a very short distance from the surface. Now we know
that, in the case of bodies within our own immediate observa-
tion, an effect takes place under certain circumstances termed
inflecion or diffraction, whereby, without passing through
any new medium, the rays of light are bent from their course
by the mere passing near the surface of those bodies. One
should suppose, therefore, that if such an effect is produced
by so diminutive an object as those which have made it ap-
parent to our observations, the immediate neighbourhood of
so vast amass of matter, for so long a time, as in the former
case, must produce some also upon the course of the more
remote rays, whether by decomposition or simple diversion.
If the latter alone were to take place in any degree, this again
would alter the apparent place of the circumference of the
hemisphere by the amount of the deviation. If no such effect
takes place at all, it is a question quite as well worthy of an
answer, why it should be so? And wherein consists the
cause of difference ?

Indeed this last remark is one which may be applied to the

* Some observations on this subject by Sir J. I. W. Herschel will be
found in L, & E. Phil. Mag., vol. iii. p. 406. See also vol, ix. p.522.—Eprv.

26 Mr.G. A. Prinsep on the spontaneous heating of Brine

whole of the preceding observations. I have put them to-
gether for the purpose of suggesting to other inquirers cer-
tain sources of agency which it would appear must be neces-
sarily followed by certain effects. That these should become
sensible in themselves is what one should naturally expect;
but if it should prove otherwise, it is worth while to inquire
how it happens that they are lost. Whether, or how, they
can be further traced I cannot now inquire; but it seems
reasonable to suppose that considerations involving time and
space to the amount of two seconds, and 400,000 miles,
ought not to be neglected as indifferent to investigations,
where appreciable phenomena supply measurements, in the
case of a wave of light, to the ten millionth part of an inch,
and the quadrillionth of a second.
I remain, Gentlemen, yours, &c.
November, 1838. J.S. W.

V. On a remarkable Heat observed in Masses of Brine kept
Jor some time in large Reservoirs. By G. A. PRINSEP,
Esq.*

JN the course of my experiments of several years in the

manufacture of salt at Balya Ghat, on the salt-water lake
east of Calcutta, I have sometimes observed a high degree of
temperature at the bottom of the brine reservoirs after they
had been filled for some weeks with brine of less than one
fourth saturation. But as the greatest heat observed did not
exceed 104° Fahr. which was under the maximum heat of the
brine on the terraces, whence the reservoirs had been filled,

I supposed the high temperature to be merely that of a warm

stream of water let in at the hottest part of the day in May or

June, and remaining below and unmixed with the cooler sur-

face water, of less specific gravity, afterwards admitted. This

opinion was strengthened by the gradual reduction of the
temperature below to nearly that of the surface, before the
end of the rainy season. I have frequently bathed in one of

the reservoirs (about 550 feet long, 35 feet wide at top and 7

or 8 feet deep), in September and October, and have found the

temperature of the water then pretty equal throughout. But
on plunging into the same reservoir on the 17th September
last, I was surprised to find the temperature near the bottom

so warm as to be intolerable to the feet. Still however I

imagined that the heat was only that which the sun had im-

parted to the terrace brine in the very sultry weather of June

last, (1837) when I had 120° registered (4th June, 4 p. m.) for

ae the Journal of the Royal Asiatic Society of Bengal, vol. vii.
Pp. ~ ’

kept for some time in large Reservoirs. 27

the brine of a terrace yielding salt: and believing the hottest
water to be therefore near the bottom I tried the temperature
there about a month afterwards by immersing an empty bottle
at the end of a bamboo, fixing the mouth so that it would be
filled about a foot from the ground. The contents when
poured out were at the temperature of 120°. A similar ex-
periment made on the same day in a circular brine reservoir
at Narainpore (120 feet diam. and about 16 feet deep) gave
104°. But on a subsequent visit to Narainpore on the 29th
October, I was startled to observe that a pump fixed against
the wall of this reservoir, for the purpose of feeding the boilers,
was actually bringing up water of the temperature of 130°
from a depth of about 12 feet. This very unexpected disco-
very determined me to contrive an instrument that should
serve as a probe to ascertain both the temperature and the
specific gravity or saltness of the water at different depths. An-
nexed is a drawing of the instrument employed: it consisted
of a split bamboo with bamboo buckets fixed between at di-
stances of one foot from centre to centre, the mouths of the
buckets being corked, but the corks having small air-holes ;
and the mode of using the machine was, to let it down with
the mouths of the buckets downwards, and then turn it round,
after which the air bubbles indicated the progress of filling ;
and in ten minutes or a quarter of an hour, when these disap-
peared, the machine was quickly drawn up and the tempera-
ture of the water in the buckets was tried rapidly in succes-
sion with a small thermometer, leaving the specific gravity to
be tried afterwards.

On the day of the first trial of this probe I was favoured
with the company and assistance of Dr. Huffnagle, who took
a lively interest in the experiment. The following particulars
are the results of all the trials I have yet made with it, the
buckets being numbered from the bottom of the machine,

First Experiment, 5th November, 9 a.m.

Open long reservoir at Balya Ghat. Probe immersed at an angle of
45° or 50°.

No. Temp,

1 106 only { full.

2 120 §.G. (appt.) 1077 at T. 117
BD lee 2 3; as 1073°5 ,, 1165
4 118 A on 1071 ate leu
5° +99 *% a 1049 oy OF
6 80 > a 1022 31 80
Hii BRT eaHvk WOR ). B)4-1 78
8 78 AP a 1021 hits
37' 78 > he 1028'5 *;,' 78

28 Mr.G. A. Prinsep on the spontaneous heating of Brine

Second Experiment, 5th November, 2 r.m. at Narainpore.

Open round brine reservoir. Probe at angle about 60° south-west side.
No, Temp.

105 (appt.) S.G. 1163 at T. 100
104 not full,
106 (appt.) S.G. 1140 ,, 104
113 2 He UGOR ern Uo
117 3 an 1161 PS
123 a 2 1157 hl ly
130 5 6 1159 ere Lets
132 “5 1153°5 4, «124
13 > oe 1145 ye 9 330)
10 131 x ae 1121 ilo
ileal z 3p 1) 1100 », 120
12 122 ag os 1090 sot
3 114 Be 5 1075 5p LOD:
14 104 a0 35 1065 6 *adlwil
15 100 A 44 1065 ROT,
16 85 a 7 1040 ee Oe
17° «84 3 3p 1044°3 ,, ~=— 883
LS 62 a3 > not full.
19 82 5 3 1038 ito 2 1

OMIA AhwWhYre

Third Experiment, 5th November, 24 P.M.

Same place and reservoir east side at gate. Probe at angle
about 75°.
No. Temp.
1 102 (appt.) S.G. 1149 at T. 100
2 106 a3 as 1145°3 ,, 103
3 109 ‘ not full
4 114 SPR SACRE LIC ere
Big hg. 5 43 WG5'5 jon ht
6 128 os > SOM asf eee
qo U37 “3 bo WSS ase eO
8 1388 55 a 139 eles
9 135 ¥ 3 1125") ,, °° 127
10 127 “A 3 LOOPHAN e120
11 114 * 25 10 7/5ies eo
12 105 49 53 1068 ,, 101
LS hie 92 =p oS 10505). ;,18 490
14 86 3 or 1040 ~,, - 84
Lace S25) 055 a3 WO Byer yl
Gi SUE yi test ae 1OS7 Ei, 64) ), 81

Fourth Experiment, 19th November, 2 p.m., at Narainpore.

Open round brine reservoir south-west side. Probe at angle 60°.
No, Temp.

104 (appt.) 5.G. 1150 atT. 102

7 108 » not full.

3 1084 a3 55... 1150 » 106

ay TTA oes 5 1148.4" Sete

—

kept for some time in large Reservoirs. 29

5 125 (appt.) S.G. 1166 atT. 120
(Tye IB Pe 5 VON is Lae
Jae aetin™ Ps 3 LOE Oe Ley
8] 133 43 a 126. ere 28
Sie 2 gee, £ a 10955 5) 4420
TOMBR Las: Ae LOZO bse LO
BINS | ears 8 a LOGIN 7 LOF
12 Oo ers: a HOST. eke 0
13 SO Siey 6 O47 se 90
14 Saas o 1046 =~ ,,_~—s 883
15 81i ,, sp 1045°6 ,, 83
16 S15) Sas a LO455 fish Sd

17 S20 ies a 1045S ,,_~— 888

Fifth Experiment, same date and place.

Covered reservoir. Probe at angle about 70°.
No. Temp.

1 88 (appt.)S.G. 1147
2 88 Fe BS 1124°5
3 90 Ye Fe 1107
4 91 ys os 1107
5 90 a 4 1102°6
6 90 P. + 1094
7 89 a Os 1081
8 88 “4 As 1078
9 874s, is 1069
10 — empty.
11 82 4 A 1054
ay not full.
14 76 1046
15 76 1046

Sixth Experiment, same date and place.
Large reservoir. Probe at angle about 80°. Tried at 25 p.m.

v4
°

Temp

1 934 (appt.) S.G. 1070
Bam ggetns jh Ug” 4/8070
3 93 _ S 1069
4 92 Pr s 1067
BSE ot hig, wild
Gwg0 As 55 1064°5
ey) AS - 1057
8 85 . A 1056
9 84 as Is 1050
10 84 “ 1050°5

11 84 (not full).
12 BEo necl sls 3080

30 Mr. G. A. Prinsep on the spontaneous heating of Brine

Seventh Experiment, 3rd December, 2 P.M. at Narainpore.
Open round reservoir, tried in the centre, probe nearly perpendicular.
No. 1 T. 107 half full.
2 110apparent S.G. 1151 at T, 106

3 114 >} és 1150 peek 0)
4 118 hy 9 TIAS SER ee ls
5 125 half full.

6 124 iy x 1114 sh iG
7 116 8 ‘5 1095 My edad
8 105 A Ad 1078°5 ,, 103
9 96 4 ee 1063°5 ,, 93
10 92 2p A LO59e tH 90
et 87 sy * 1054

12 S60 sey s 1053°7

13 84 half full.

14 82 “3 43 1052

Ty 81 , yy 1053

16 82 a 33 1052

17 82 1051

In the first trial at Narainpore the greatest heat was found
about half-way from the bottom, The difference in that re-
spect at Balya Ghat, where the greatest heat appeared at the
second and third foot from the bottom, may be explained by
the small depth of the reservoir at the latter place, the surface
water being liable to be affected to the same depth in both
by the wind and rain and temperature of the atmosphere; and
the subsequent descent of the maximum heat at Narainpore
is attributable in part to the expenditure of the brine there,
being pumped out from near the bottom for the supply of the
boilers. ‘The highest temperature given by the probe at
Narainpore was 137°, but this is 5° less than the maximum
given by the pumps, as will be seen by the following state-
ment.

29 Oct. N. pump T. 130 8. G. (cor.) 1180
TON Gve 87 S70e” ASS TRY mL 0
VE) Ui Bars RMN Sas ey 1S 0 ees 5 iG?
26 9243 oa 5 OS: nie poe
2Dec. «35 055 LAPS » 1133 8.pump 1348.G.1172
LO e545 ull iy > SS ee se » LAS: ye, 24 Ais

1 eee anroriey irae) he ges 55 TG) toys ay LO4s Gs eS
DAY ees farssnes ose ATO oa 55, WAS) i 53h DLL ea
il ee rere On Be soricn hl (A ie, Dati pele
TaD Aller 5 ce 55 ook Me ee sy, Leh LOBH Ws, ty Obie aes
13 ,, (sunk 2fect) 104s, sate LA. 3 LOWRIE emul

LE 92: 5 ED
THO ager Mets, TS PEERS GRE ae eeckctetetee Va Nadie et ole tame CTE y 90 53) ALLO

As the temperature of 90° was only about the mean of
June, and also that of the lower moiety of the brine in the

ted

kept for some time in large Reservoirs. 31

covered reservoir on the 19th November, which was all nearly
of an equable temperature, I consider the influence of the
heating course to have ceased in the first week of February, if
not before. The reservoirs have since been pumped dry, and
therefore these experiments cannot be repeated, until they
are replenished with brine in April or May next.

It is remarkable that the probe indicated no signs of a
heating influence affecting the water in the large reservoir at
Narainpore on the 19th November, though the specific gravity
of the brine near the bottom was little less than that of the
water in the long reservoir at Balya Ghat on the 5th Novem-
ber, its mean spec. grav. being also considerably higher than
the mean of the latter. Moreover the heating influence was
scarcely traceable in the covered brine reservoir at Narain-
pore on the 19th November, which perhaps may be accounted
for by the large previous expenditure of brine, say about three-
fourths of its original contents, the consumption of which had
been replaced to within a foot of the general level by filtration
from the ground and leakage at the gate communicating with
the adjoining terrace and brine fields; whereas the expendi-
ture of brine in the contiguous open round reservoir other-
wise similarly situated, was but half of the original contents
up to the middle of January, its entire volume being about
170,000 cubic feet, while the covered reservoir contained only
about 50,000. In these two reservoirs all the brine when
first let in was of a high degree of saturation, ranging from
1170 to 1200 sp. gr. and consequently containing little or no
sulphate of lime, which ingredient in the composition of sea~
water, I have observed at Balya Ghat, is always deposited
upon the terraces there, considerably before the brine begins
to deposit its sulphate of soda. But this was not the case with
respect to the brine in the large reservoir at Narainpore, nor
in that of a longer narrow one at Balya Ghat, except perhaps
a small proportion of the latter, both of which were charged
with brine of only1070 to 1085 sp. gr., a much higher degree
however than that of the contents of the long reservoir in any
previous year; and in both of them the water nad remained
undisturbed, except by the action of the atmosphere; yet in
one of them a high degree of heat was observed, and in the
other, where I should sooner have expected to find it, no in-
dication of heat was perceived beyond the probable tempera-
ture at which it was filled in June.

In order to ascertain however whether any fermentation
and disengagement of heat takes place on the mixture of
saturated brine with brine of a weaker degree, I lately pro-
cured from Bulya Ghat some bottles of brine of different de-

32 Sir John F. W. Herschel’s Chemical Examination of

grees of saturation, with which the following experiments were
tried.

1st Experiment.—Half a pint of saturated brine sp. gr. 1216,
temperature 82°5 mixed with about the same quantity of brine
of sp. gr. 1069, temperature 81°2. Result, temperature 82°2
and no effervescence after standing some minutes.

2nd Experiment.—Same quantities of brine sp. gr. 1216,
temperature 82°5, and of brine sp. gr. 1091, temperature 81°.
Result, sp. gr, 1152-5, temperature 82:2 and no effervescence.

3rd Experiment.—Same quantities of brine sp. gr. 1216,
temperature 82°5, and sp. gr. 1135, temperature 81°6. Re-
sult, sp. gr. 11743, temperature $2°1 and no effervescence,
nor any increase of temperature after remaining some hours
in the glass.

Being therefore quite unable to offer any explanation of the
cause of the remarkable heat observed in my brine reservoirs,
I can only promise to register the temperature from time to
time when they are filled again, in the hope that materials
may thus be furnished to some scientific friend more capable
of solving the interesting problem. If it should be discovered
that a slow fermentation arising from the mixture of brine of
different densities in large masses is the cause of this heat, it
wou:d seem to be accelerated by agitation, for the water raised
by the pumps was always warmer than that which the probe
brought up from the same depth; and, except at the first
trial at Narainpore, always hotter than the maximum given
by the probe.

VI. Notice of a Chemical Examination of a Specimen of
Native Iron, from the East Bank of the Great Fish River,
in South Africa. By Sir Joun ¥. W. Herscuet, Bart,
M.A, F.R.S.*

(THE [portion analysed of the] specimen in question weighed
originally 21°79 grains, 5°12 of which were separated, and
submitted to a hasty preliminary examination for the detection
of nickel, if any ; but the quantity proving too small, the whole
of the remainder was operated on in a subsequent trial.
The iron was highly malleable and tenacious, and appa-
rently of excellent quality, with a somewhat whiter and more
silvery lustre than belongs to the metal in its ordinary state,

* Read before the Literary and Scientific Institution of South Africa :
now extracted from Sir James E. Alexander’s ** Expedition of Discovery
into the Interior of Africa.” Lond. 1838, vol. ii. Appendix, p. 272. ‘The
specimen had been found by Sir James Alexander, and presented by him
to the Institution.

a Specimen of Native Iron from South Africa. 33

and apparently little liable to oxidation, qualities which are
observed in iron, of what is usually considered undoubted
meteoric origin.

I should not think it necessary to detail the steps of the
analysis by which the presence of nickel in the proportion of
4°61 per cent. was demonstrated, but for a peculiarity in one
part of the process by which an inconvenience of frequent
occurrence in chemical operations, and of a very embarrassing
nature, was obviated, and which may prove useful as a hint to
young analysts in other cases.

18°67 grains of the iron in one piece were digested in
dilute nitric acid, which dissolved the whole, with the excep-
tion of a trifling quantity of black scaly matter, apparently
amounting to about a quarter of a grain*. ‘Towards the end
of the solution the iron more than once brightened on the
surface, and assumed that peculiar and singular state of re-
sistance to the action of the acid which I have described in
the Annales de Chimie for September 1833, and which has
since been the subject of so much interesting discussion by
Professor Scheenbein, Mr. Faraday, and otherst. In con-
sequence, it was necessary to apply and maintain heat to
complete the solution.

The nitric solution was evaporated to dryness, water
added, and evaporated a second and a third time. By this
the whole of the iron was peroxidized, and nearly the whole
separated. It was then diffused and boiled in water, to which
a few drops of nitric acid were added, to take up any oxide
of nickel which might have been deprived of its acid by over-
heating, and set aside for subsidence, filtration being out of
the question.

After standing a week, however, it was still perfectly
opake, and loaded with suspended peroxide of iron, and to
get rid of this was the next object.

Lead being a metal easily eliminated, and incapable of
interfering in any of the subsequent processes, its introduc-
tion seemed not likely to prove any source of further em-
barrassment; a few drops of dilute nitrate of lead were there-
fore added; and being well mixed, as much sulphuric acid as
would saturate the lead, and a little more, was added, and the
whole boiled. The precipitation was complete, the lead car-
rying down with it all the suspended ferruginous matter, and
leaving a clear liquid of a greenish hue, in which the presence
of lead could not be detected.

* This black scaly matter was in all probability graphite.—Epit.
+ See L. and E, Phil. Mag. vol, xi. p. 829.—Ebir,

Phil. Mag. S. 3. Vol. 14. No. 85. Jan. 1839. D

34 Mr. Faraday’s Supplementary Note to Experimental

The remaining iron held in solution was removed by
heating it with excess of carbonate of lime, in the manner
pointed out by me in the Phil. Trans. for 1821*, when after
filtration, a liquid remained of that peculiar tint of pale
green which characterizes the solutions of nickel, and of con-
siderable intensity.

The presence of this metal was ascertained on concen-
trating the solution by the usual tests, and its quantity con-
cluded, viz. 0‘86 grains, or 4°61 per cent. on the specimen
analysed.

Thus it appears that the specimen brought home by
Capt. Alexander has equal claim to a meteoric origin with
any of those masses of native nickeliferous iron which have
been found in different localities, and to which that origin
has, without other evidence, been aitributed.

All those specimens, however, have, so far as I know,
been insulated single masses. But what constitutes the pe-
culiar and important feature of this discovery of Capt. Alex-
ander, is the fact stated by him of the occurrence of masses
of this native iron in abundance, scattered over the surface
of a considerable tract of country. If a meteoric origin be
attributed to all these, a shower of iron must have fallen; and
as we can imagine no cause for the explosion of a mass of
iron, and can hardly conceive a force capable of rending
into fragments a cold block of this very tenacious material,
we must of necessity conclude it to have arrived in a state of
fusion, and been scattered around by the assistance of the
air or otherwise, in a melted, or at least softened state.

VII. Supplementary Note to Experimental Researches in
Electricity. —Eleventh Series. By Micwart Farapay, Esq.,
D.C.L. F.RS. Fullerian Prof. Chem. Royal Institution,
Corr. Memb. Royal and Imp. Acadd. of Sciences, Paris,
Petersburgh, Florence, Copenhagen, Berlin, Sc. §c.t

1307. I HAVE recently put into an experimental form

that general statement of the question of specific

inductive capacity which is given at No. 1252 of Series XI.,

and the result is such as to lead me to hope the Council will

authorize its addition to the paper in the form of a supple-
mentary note. Three circular brass plates, about five inches
in diameter, were mounted side by side upon insulating pil-

* Sir John Herschel’s paper here alluded to will be found in Phil. Mag.
First Series, vol. lix. p. 86; and in the Annals of Philosophy, New Series,
yol. iii. p. 95.—Eprr.

+ From the Philosophical Transactions for 1838, Part i.

Researches in Electricity. (Series XI.) 35

lars; the middle one, A, was a fixture, but the outer plates
B and C were moveable on slides, so that all three could be
brought with their sides almost into contact, or separated to
any required distance. Two gold-leaves were suspended in
a glass jar from insulated wires; one of the outer plates B was
connected with one of the gold-leaves, and the other outer plate
with the other leaf. The outer plates B and C were adjusted
at the distance of an inch and a quarter from the middle
plate A, and the gold-leaves were fixed at two inches apart ;
A was then slightly charged with electricity, and the plates
B and C, with their gold-leaves, thrown out of insulation
at the same time, and then left insulated. In this state of
things A was charged positive inductrically, and B with C
negative inducteously ; the same dielectric, air, being in the
two intervals, and the gold-leaves hanging, of course, parallel
to each other in a relatively unelectrified state.

1308. A plate of shell-lac three quarters of an inch in
thickness, and four inches square, suspended by clean white
silk thread, was very carefully deprived of all charge (1203.),
so that it produced no effect on the gold-leaves if A were un-
charged, and then introduced between plates A and B; the
electric relation of the three plates was immediately altered,
and the gold-leaves attracted each other. On removing the
shell-lac this attraction ceased; on introducing it between A
and C it was renewed; on removing it the attraction again
ceased; and the shell-lac when examined by a delicate Cou-
lomb electrometer was still without charge.

1309. As A was positive, B and C were of course nega-
tive; but as the specific inductive capacity of shell-lac is about
twice that of air (1270.), it was expected that when the lac
was introduced between A and B, A would induce more to-
wards B than towards C; that therefore B would become
more negative than before towards A, and consequently, be-
cause of its insulated condition, be positive externally, as at
its back or at the gold-leaves; whilst C would be less nega-
tive towards A, and therefore negative outwards or at the
gold-leaves. This was found to be the case; for on which-
ever side of A the shell-lac was introduced the external plate
at that side was positive, and the external plate on the other
side negative towards each other, and also to uninsulated ex-
ternal bodies.

1310. On employing a plate of sulphur instead of shell-
lac, the same results were obtained; consistent with the con-
clusions drawn regarding the high specific inductive capacity
of that body already given (1276.).

D2

36 Nature of the differential Inductometer.

1311. These effects of specific inductive capacity can be
exalted in various ways, and it is this capability which makes
the great value of the apparatus. Thus I introduced the
shell-lac between A and B, and then for a moment connected
B and C, uninsulated them, and finally left them in the insu-
lated state; the gold-leaves were of course hanging parallel
to each other. On removing the shell-lac the gold-leaves at-
tracted each other; on introducing the shell-lac between A
and C this attraction was zzcreased, (as had been anticipated
from theory,) and the leaves came together, though not more
than four inches long, and hanging three inches apart.

1312. By simply bringing the gold-leaves nearer to each
other I was able to show the difference of specific inductive
capacity when only thin plates of shell-lac were used, the rest
of the dielectric space being filled with air. By bringing B
and C nearer to A another great increase of sensibility was
made. By enlarging the size of the plates still further power
was gained. By diminishing the extent of the wires, &c.
connected with the gold-leaves, another improvement re-
sulted. So that in fact the gold-leaves became, in this man-
ner, as delicate a test of specific inductive action as they are,
in Bennet’s and Singer’s electrometers, of ordinary electrical
charge.

1313. It is evident that by making the three plates the
sides of cells, with proper precautions as regards insulation,
&c., this apparatus may be used in the examination of gases,
with far more effect than the former apparatus (1187. 1290.),
and may, perhaps, bring out differences which have as yet
escaped me (1292, 1293.).

1314. It is also evident that two metal plates are quite suf-
ficient to form the instrument; the state of the single induc-
teous plate when the dielectric is changed, being examined
either by bringing a body excited in a known manner towards
its gold-leaves, or, what I think will be better, employing a
carrier ball in place of the leaf, and examining that ball by
the Coulomb electrometer (1180.). The inductive and in-
ducteous surfaces may even be balls; the latter being itself
the carrier ball of the Coulomb electrometer (1181. 1229.).

1315. To increase the effect, a small condenser may be
used with great advantage. Thus if, when two inducteous
plates are used, a little condenser were put in the place of the
gold-leaves, I have no doubt the three principal plates might
be reduced to an inch or even half an inch in diameter. Even
the gold-leaves act to each other for the time as the plates of
a condenser. If only two plates were used, by the proper

Mr. Ivory on the Equilibrium of Fluids. 37

application of the condenser the same reduction might take
place. This expectation is fully justified by an effect already
observed and described (1229.).

1316. In that case the application of the instrument to very
extensive research is evident. Comparatively small masses
of dielectrics could be examined, as diamonds and crystals.
An expectation, that the specific inductive capacity of cry-
stals will vary in different directions, according as the lines
of inductive force (1304.) are parallel to, or in other positions
in relation to the axes of the crystals, can be tested: I pur-
pose that these and many other thoughts which arise respect-
ing specific inductive action and the polarity of the particles
of dielectric matter, shall be put:to the proof as soon as I can
find time.

1317. Hoping that this apparatus will form an instrument
of considerable use, I beg to propose for it (at the suggestion
of a friend) the name of Differential Inductometer.

Royal Institution, March 29, 1838.

VIII. On the Equilibrium of Fluids, occasioned by an Ar-
ticle of Professor Sylvester on Fluids, published in this
Journal for December 1838. By J. Ivory, K.H., F.RS.*

PROFESSOR Sylvester has deduced the usual laws of the

equilibrium of incompressible fluids from a principle
proposed by the eminent mathematician and philosopher
Gauss. Not to speak of the motion of fluids, the theory of
which is pressed by so many difficulties, the results respecting
equilibrium obtained by the Professor coincide ‘entirely with
what has been investigated from principles, seemingly different,
by Clairaut, Euler, Lagrange, Laplace, and Poisson, this
last having extended his views to the molecular forces that
act upon the particles. Such a concurrence in the conclu-
sions arrived at, begets a suspicion that in reality all the pro-
cesses are guided by one invariable principle, which, although
hidden under algebraic operations, necessarily conducts the
analyst to the same landing-place. To prove that this is ac-
tually the case is the intention of what follows.

The general laws of equilibrium in question are deducible
from the following theorem, which is grounded on the most
general conception of fluidity that can be formed. In a fluid
at rest, the particles of which are urged by accelerating forces,
the pressure at the several points of the mass, can be mathema-
tically expressed only by a function of the coordinates that

« Communicated by the Author.

38 Mr. Ivory on the Equilibrium of Fluids.

determine the position of the point of action, these coordinates
being considered as unrelated and independent quantities. ‘To
prove this, take any two points of the mass, and let a com-
munication be made between them by a canal of any figure:
if to the pressure of the fluid on the orifice of the canal at
one end, we add the effort of the fluid contained in the canal,
caused by all the forces that urge the particles in the direc-
tion of the canal, the result will counterbalance the pressure
on the orifice at the other end; wherefore, in a fluid at rest,
the effort of every canal, of whatever figure, will be the same,
provided the extreme orifices are the same. Now it is easy
to ascertain that this property will be fulfilled when the sort
of function described in the theorem stands for the pressure ;
and an application of the method of variations will show that
no other sort of function will answer the same end.

The theorem being demonstrated, let X, Y, Z denote the
accelerating forces that urge a particle of the fluid in the re-
spective directions of its coordinates, 2, y, 2; the differential
of the pressure will be

Xdx+Ydy+ Zdz: (a.)
and, as the fluid is at rest, this must be the differential of a
function of a certain kind, by the theorem ; and, on the other
hand, if it be an exact differential, it can be derived only
from a function of the sort mentioned. Wherefore, in a fluid
in equilibrium, the expression (a.) is always an exact diffe-
rential, and it is zero at the upper surface, because the press-
ure is constant at that surface.

The foregoing reasoning holds, whatever modification, or
assumption, is superadded to the notion of fluidity, The
mathematical laws of the equilibrium of fluids are thus placed
on the broadest foundation. They are sufficient for deter-
mining the figure of equilibrium when the integral of (a.) is
an explicit function of the coordinates; but they are not suffi-
cient when the same integral is only an implicit function, that
is, when the forces in action are derived from different
sources, and are independent on one another; in which ease,
as common sense dictates, recourse must be had to the pecu-
liar circumstances of the problem in order to complete the
solution.

It deserves to be noticed that the theorem is true, and the
expression (a.) is an exact differential, in a fluid at rest, but
not in one in a state of motion; which marks a distinction be-
tween the mathematical laws that govern the two cases: yet
‘ is usual to deduce the motion of fluids from their equili-

rium.

December 17, 1838. James Ivory.

[ 39 ]

IX. Observations on Shooting Stars made on the Night of
November 12 to 13, 1838, at Whitechapel, London. By
Mr. W. R. Birt, Librarian and Assistant Secretary to
the Metropolitan Literary and Scientific Institution.*

D, Signifies that the motion of the shooting star was direct, R. that it
was retrograde.

No. Time. Direction.
1. 9 20 From middle Ursa Major to Auriga. R.
2. 9 30 From between Gemini and Orion’s head to ho-
rizon, inclined to north: D.—Character: Brilliant, slow.
3. 9 50 From 6 Aurige to d Geminorum: D.— Faint.
4. 1020 From middle of Ursa Major to between §
Gem. and Castor. R.—Very faint.
5. 1045 From Gemini across 8 Tauri to between the
Pleiades and Hyades. R.—Very swift.
6. 1047 Irom north of Capella to middle of Ursa
Major towards the horizon, D.—Very brilliant. Train.
+ 7. 10 55 From below Pollux between y and & Gem. to
a Orionis. R.—Very brilliant with splendid blue train.
? 8. 11 5 From about three degrees below Pollux to-
wards the horizon. D.—Very short.
? 9. 11 27 From north of Capella to middle of Ursa Ma-
jor. D.—Faint.
10. 11 30 From 4 Aurigze towards Ursa Major. D.—
Small.
11. 11 44 From a little below 8 Canis Minoris towards
E. inclined to horizon. D.—Small.
? 12. 11 50 Across 8 Canis Majoris towards the south. R.
13. 11 54 From Castor and Pollux across Aldebaran.
R,—Very swift, slight train.
14. 11 59 Between Capella and @ Aurigze towards N.
little E. of zenith. R.—Bright,
15. 12 17 Midway between Leo and Ursa Major to-
wards north. D,—Small, long.
16. 12 22 Between the feet of Ursa Major towards
Virgo. D.—Small.
17. 12 24 North of Leo towards the north. D.—Small.
18. 12 28 Between a and y Leonis towards Virgo. D.
—Small.
19. 12 34 From e past y Geminorum towards Sirius.
D.—Small,
12 40 Bright light horizon NE. D.

* Communicated by the Author.

40 Mr. W.R. Birt’s Observations on Shooting Stars.

No. Time. Direction.
ZO. 1245 From 2» and pw Urse Majoris past v and &
U. M. to tail of Leo. D.—Small.
21. 12 54 Between 8 Canis Majoris and « Orionis to-
wards south. R.
22. 12 57 Across 8 Leporis to west. R.
23. 13 5 From Canis Minor to Cancer. D.—Small.
24. 1313 From Cancer to Caput Hydre. D.—Small.
25. 13 26 From Leo Minor to y Leonis. R.—Small.
26. 13 28 From y to » Urs Majoris. D.
27. 13 29 From y to between ¢ and (A and mw) Urse
hg R.
98. 13 37 Fromztoy Urse Majoris. D.
1 20: : 54 From v Urs Majoris to a Canes Venatici.
D.—Brilliant. Train some seconds.
30. 14 3 Frome Ursz Majoris past ¢ by north of these
stars. D.—Small.
31. 14 7 From Leo towards Procyon between Cancer
and Caput Hydre. R.—Small.
32. 14 14 From Caput Leonis across Cancer to 8 Canis
Minoris. R.—Bright, very swift.
33. 14 17 From 22 Monocerotis to y Geminorum. R.
—Small.
34, 14 25 In Leo Minor towards the horizon. D.—Very
small,
35. 14 26 From toy Urse Majoris. D.—Small.
14 28 Splendid Aurora Borealis. Streamers.
greenish, summits deep red, 4 § Draconis.
36. 14 36 From v Urse Majori is between a Canes Ve-
natici and 8 Leonis. D.
37. 14 44 Tothe north of Leo from yp too. D.—Bright.
$8. 15 1 Between Draco and tail of Ursee Majoris to-
wards horizon. D.—Small.
15 4 Second coloured Aurora.
39. 15 5 From 6éto Cor Hydre. D.
40. 15 5 Small one at right angles to above Caput
Hydre. R. .
41. 15 21 From @ and y Urse Minoris to 4 Draconis.
D.—LIregular, partly extinguished.
42, 15 32 Between a Canes Venatici and Coma Bere-
nices towards Bootes. D.
43. 15 44 From y past e to € Urse Majoris. D.—Swift.
44. 15 51 Fromy ie v Ursee Majoris to o Leonis. D.
—Bright.
160 . Third epignned Aurora.

Mr. W. R. Birt’s Observations on Shooting Stars. 41

No. Time. Direction.

45. 16 3 Considerably below Draco between it and
Bootes N.E. D.—Very brilliant.

46. 16 12 From between a Canes Venatici and Coma
Berenices towards Bootes. D.—Swift ? small train.

47. 16 18 From o past 8 and y Draconis. R.—Path

curved.
48. 16 24 From Leo Minor to Coma Berenices. D.
—Small.

49. 16 43 From 7 Urs Majoris toCaput Draconis. D.

50. 16 59 From below the moon towards the horizon.
D.—Bright.

5l. 17 8 From between a Canes Venatici and Coma
Berenices to Arcturus. D.—Bright, swift.

52. 1711 Past » Bootes towards the horizon. D.—
Small.

53. 17.14 From § to 8 Bootes. D.—Small.

54. 17 25 From Coma Berenices to y Bootes. D.—
Small.

The +’s prefixed indicate the two most brilliant of the
shooting stars observed.

I am not certain which of the two 45 and 46 left the small
train; it was observed with one of them.

At the commencement of the observations the meteors ap-
peared to emanate from, or approached to, a line drawn
through Castor and Pollux; as the night advanced and Ge-
mini approached the meridian, this line was frequently crossed;
still a line parallel to it might be regarded as the axis which
the ‘meteors either emanated from or approached to, until
they becoming more widely diffused over the eastern hemi-
sphere, and their directions more varied, such an axis ceased
to be recognised.

As the observer commanded only the eastern quarter of the
heavens from north to south, an inspection of the following
table, in which the meteors are arranged according to the
constellations in or near which they appeared, will show
where they were most numerous in that quarter, namely, a
little north of east. The constellations in the second column
were within view of the observer during the night, while they
were above the horizon. The whole of the constellations in
the table are arranged (as nearly as possible for this method)
according to their relative situations in the heavens.

Mr. W. R. Birt’s Observations on Shooting Stars.

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X. On the Voltaic Polarization of certain Solid and Fluid
Substances. By Prof. SCH@NBEIN.

To the Editors of the Philosophical Magazine and Journal.
GENTLEMEN,

READ a paper containing an account of the results of

my researches on the voltaic polarization of solid and fluid
bodies, before the scientific meetings which took place at
Bale and Fribourg, some months ago.

This memoir, I think, will soon be published in the
Biblioth. Univ. and in Poggendorft’s Annalen, and the sci-
entific public thereby enabled to appreciate the facts re-
lated init. The sort of investigations alluded to could not
but lead me to make numerous experiments similar to those
which were mentioned the other day in the French Academy,
as performed by MM. Matteucci * and Peltier, of which I have
however, up to this present moment, but a very imperfect
knowledge. Having from want of time not yet been able to
draw up a regular paper on the results of my most recent
voltaic researches, and thinking them not quite void of sci-
entific interest, I beg the favour of your giving in the forth-
coming Number of your widely circulated Journal a place to
the general statements, the tenor of which is as follows :

1. A platina wire polarized either in the positive or nega-
tive way loses its peculiar condition by being heated red-hot.
(I call positively polarized a wire which has acted for some
time the part of the negative electrode in water slightly acidu-
lated by sulphuric acid; and I term negatively polarized a
wire which has in the same liquid performed the function of
the positive electrode.)

2. A platina wire positively polarized loses its peculiar con-
dition by being plunged only for a single moment into an at-
mosphere of chlorine.

3. A platina wire positively polarized loses likewise its
electromotive power by being placed in an atmosphere of
oxygen; but in order to destroy entirely the polarity of the
wire, it is necessary that it should remain for some seconds
in the gas mentioned.

4. A platina wire negatively polarized loses its peculiar
condition by being put into an atmosphere of hydrogen, but
in order to obtain this effect, it is required that the wire in
question should remain for some seconds in the gas.

5. A platina wire polarized either negatively or positively
is not sensibly affected by being placed in an atmosphere of

* See p. 469 of our last number and volume.—Ebrr.

44: Prof. Schcenbein on the Voltaic Polarization

carbonic acid or in one of any other gas which does not che-
mically act either upen hydrogen or oxygen.

6. A platina wire (in its natural state) assumes in every
respect the condition and voltaic bearings of a positively po-
larized wire by being plunged only for a few seconds into an
atmosphere of hydrogen.

7. Gold and silver are not sensibly affected under the same
circumstances.

8. A platina wire does not acquire any degree of electro-
motive power by being put into oxygen gas: the metal re-
mains in its natural state. Neither is any degree of such
power acquired by gold or silver under the same circum-
stances.

9. Platina, gold, and silver, by being placed only for a few
seconds in an atmosphere of chlorine, assume the voltaic state
of a negatively polarized wire.

10. Water slightly acidulated with sulphuric acid and
holding some hydrogen dissolved, bears to acidulated water
containing no hydrogen the same voltaic relation that zinc
does to copper; provided, however, both fluids be separated
from each other by a membrane, and connected with the gal-
vanometer by means of platina wires. If for the latter pur-
pose (that is to say, for connecting the fluids with the galva-
nometer) gold or silver wires are made use of, the said fluids
do not excite the least current.

11. Two fluids, one being acidulated water containing some
oxygen dissolved, the other being likewise acidulated water con-
taining no oxygen, appear to be in a voltaic point of view
perfectly indifferent to each other, whether they are con-
nected with the galvanometer by platina, silver, or gold wires.

12. Water slightly acidulated with sulphuric acid and
holding some chlorine dissolved, bears to acidulated water not
containing any chlorine the same voltaic relation that copper
bears to zinc. In other terms, the former fluid acts under cer-
tain circumstances the electromotive part of the peroxides of
silver, lead, &c.

13. The aqueous solution of hydrogen mentioned in § 10,
loses its property to excite a current by being mixed with
a certain quantity of an aqueous solution of chlorine; and,
vice versd, the latter fluid loses its electromotive power men-
tioned in the § 12 by being mixed with a sufficient quantity
of hydrogen dissolved in water.

14. Muriatic acid positively polarized loses its peculiar vol-
taic condition by being mixed with some chlorine, and the
same acid being negatively polarized loses its polarity by be-

* . 5
ing treated with some hydrogen. From the facts stated, and

of certain Solid and Fluid Substances. 45

others which are mentioned in the memoir above alluded to,
a great number of rather important inferences might be
drawn; but having for the present no leisure time to do so,
I am obliged to confine myself to stating those which follow:

a. The secondary currents produced both by polar wires,
electrolytic fluids, and secondary piles, are due to chemical
action, 1. e. (in the cases mentioned) to the union of oxygen
with hydrogen, or to that of chlorine with hydrogen ; and not,
as M. Peltier seems to think, to the mere act of the solution
in water of the gases mentioned,

b. The chemical combination of oxygen and hydrogen in
acidulated (or common) water is brought about by the pre-
sence of platina in the same manner as that metal determines
the chemical union of gaseous oxygen and hydrogen.

c. The current produced by a platina wire being sur-
rounded by a film of chlorine, or by water holding chlorine
in solution, is not dependent on the action of the latter body
upon platina, but on the action of chlorine upon the hydrogen
of water.

d. Electrolytic bodies do not suffer even the weakest cur-
rent to pass through them without undergoing decomposition.
(This inference is drawn from the fact ascertained by me
some time ago, that platina wires acting as electrodes in mu-
riatic acid are polarized by a current so weak as not to be
able to electrolyze even iodide of potassium).

e. The most delicate test to ascertain that electrolyzation
has taken place, is the polarized state of the electrodes.

I cannot close my letter, Gentlemen, without taking the
liberty to point out to you the beautiful, and, as it seems to me,
most conclusive evidence in favour of the correctness of the
chemical theory of galvanism, now so much contested, which
is afforded by the tact stated in §10. If the mere contact
of the two different fluids mentioned there were the real cause
of the current obtained, it is obvious that the same current
ought to be produced whether the fluid be connected with
the galvanometer by means of gold, or if they be connected
with the instrument by that of platina wires; but the result
being determined by the nature of the connecting wires, and
platina being known to favour the union of hydrogen and
oxygen, whilst gold and silver do not possess in any sensible
degree that property, we are entitled to assert that the current
in question is caused by the combination of hydrogen with (the)
oxygen (contained dissolved in water) and not by contact.

I am, Gentlemen, yours, &c.

Baile, Dec. 1838, C.F. Scoa@npern.

[ 46 ]

XI. On the Formule representing Chabasie, in a Letter to
Professor Johnston. By R. Puwups, F.R.SS., L. & LE.

My pear JOHNSTON,
T° your paper, contained in the last Number of this Journal,

‘On some apparent exceptions to the law, that like cry-
stalline forms indicate like chemical formule,” you have ap-
pended this note: “If Mr. Phillips will look at the formula
for chabasie given in the table, his difficulty about the mu-
tual replacement of potash and soda will or ought to dis-
appear.”

Before however doubts can cease to exist, clear grounds
must be stated for their removal; allow me therefore to direct
your attention to the very different statements which you
have made at various and not very distant periods, respecting
the composition of chabasie.

In the London and Edinburgh Philosophical Magazine,
vol. ix. p. 168, you observe that “‘ chemists have recognised
two varieties of chabasie; one from Aussig in Bohemia, and
from Fassa, analysed by Hoffman, and from Faroe analysed
by Arfvredson; eae by the formula,

N +S?+3AS? + 6 Aq,

K
and another from Nova Scotia, analysed by Hoffman, from
Gustafsberg, by Berzelius, and from Kilmacolm, by Mr.
Connell, represented by the formula,

C

N bs3 + 8AS? +6 Aq.”
K

As chemical formule the above have no meaning; the latter,
I presume, was intended to include the mzneralogical formula
of lime chabasie, as given by Berzelius, Nowveau Systeme de Mi-
neralogie (p. 219), CS?+3 AS?+6 Aq. But you have omitted
to adopt a necessary precaution in employing mineralogical
formule ; for Berzelius says, “pour éviter toute espéce de
confusion, qui pourrait provenir des deux sortes de formules,
je marquerai les minéralogiques en caracteres italiques.”

In the Report of the British Association, vol. vi. p. 176,
you have thus represented

Na?
‘‘ Chabasie K® Si? AL 3AlSi? + 18H.”
Ca’

In the above formula, owing, as I suppose, to the slipping
of one of the marks representing an equivalent of oxygen,

Note by Professor J. J. Sylvester. 47

aluminium looks like a binoxide and silicium a quadroxide.
I believe that three of the dots were intended for the Al, and
three for the Si; if I am wrong you will be good enough to
settle this point*.

Lastly, in the London and Edinb. Phil. Mag. for Decem-

ber, you have given as the formula for
Ca?
“‘ Chabasie Na® & Si? + 3 Al Si? + 10 H.”
K3

Now mark the differences of these formule: in the two
first we find 6 atoms of water, in the third 18, and the fourth

10 atoms. Al énéended in the third formula means teroxide of

aluminium, but I imagine it ought to have been Al, a sesqui-
oxide, as in the fourth formula*.

You will greatly diminish the difficulties which you have
thus created by favouring me with the following statements :

The weight of the atom of lime, potash, soda, aluminium,
alumina, silicium, silica, and water, the symbol of each, the
number of atoms of each contained in chabasie, and the mode
in which you consider that the various silicates which chabasie
contains are constituted, with their atomic weights and
symbols.

When you have complied with the above request, I will
endeavour to see what I ought; but at present, with data to be
colJected from four discordant formule, I see nothing but
confusion. I remain,

My dear Johnston, yours faithfully,

London, Dec. 12, 1838. R. Puriiies.

XII. Note by Professor J. J. Sylvester on his former Paper
inserted in the London and Edinburgh Philosophical Ma-
gazine for December, 1838.

University College, London, Dec. 13, 1838.
HAVE to apologize for calling “ original” (in the last
Number of the Magazine) the theorem of numbers which I
termed “a pendent to Horner’s theorem.” This Mr. Ivory
has done me the honour to inform me may be found in Gauss’s
Disquisitiones Arithmetica, page 76. As Horner’s extension

* As evincing the extent to which an accident (against which no care of
the printer can always sufficiently guard) may occur in this mode of sym-
bolizing oxygen, I may mention that in the proof of this communication, the

three dots intended for this Al, had retrograded to the previous word.

48 Geological Society.

of Fermat’s theorem suggested this extension of Sir John Wil-
son’s to me, so I concluded that had this extension of Wilson’s
been known to the world it would naturally have suggested his
to Horner. No acknowledgement of this kind having been
made, I took it for granted that the theorem I gave was new.
Undoubtedly had Mr. Horner been aware of Gauss’s theorem
he would have made mention of it. -My acquaintance with
Gauss’s principle has not been derived from the study of his
works, but from a casual statement of it in an English work,
* Dynamics,” by Mr. Earnshaw, of St. John’s College, Cam-

bridge.

XIII. Proceedings of Learned Societies.
GEOLOGICAL SOCIETY.

Nov. 7, 1838.—A paper was first read, On some Fossil Remains
of Palzotherium,Anoplotherium, and Cheropotamus, from the fresh-
water beds of the Isle of Wight, by Richard Owen, Esq., F.G.S.,
Hunterian Professor in the Royal College of Surgeons.

Some years previous to 1825, Mr. Thomas Allan, of Edinburgh,
found in the freshwater beds at Binstead in the Isle of Wight, a tooth
which was subsequently determined by Mr. Pentland, to be a molar
of the Anoplotherium commune*; and in 1830, Mr. Pratt found in
the same quarries teeth of one species of Anoplotherium and of two
species of Paleotherium+; and thus the freshwater strata of the
Hampshire basin were proved to contain remains of some of the Pa-
chydermata which had been discovered in the gypsum quarries of
Montmartre.

The specimens described by Mr. Owen in this paper were col-
lected by the Rev. W. Darwin Fox, at Binstead and Seafield; and
being numerous and well preserved they have enabled the author to
establish a still greater agreement in the remains of the two locali-
ties. Of the genus Palotherium, the collection contained teeth
and bones of P. medium, P. crassum, P. curtum? and P. minus ;
and of the genus Anoplotherium, teeth of 4A. commune and A. secun-
darium.

The most important specimen, however, in the collection is a right
ramus of the lower jaw of the Cheropotamus, wanting only one false
molar, a small portion of the symphysis, and the top of the coronoid
process.

This genus was established by Cuvier from an imperfect fragment
of the base of the skull, with six molar teeth on each side, and a
small portion of a ramus of the lower jaw with the canine ? and two
spurious molars. He nevertheless proved from the form of the teeth,
the glenoid cavity, and the zygomatic arches, that the animal be-
longed to the Pachydermata and was most nearly allied to the Pec-

* See a paper by Dr. Buckland, Annals Phil. New Series. vol. x, p. 360.
+ Geological Transactions, Sec. Ser., vol. iii. p. 451.

Geological Society. 49

cari. In some points, however, in which these remains deviate from
the Peccari, they were shown by Mr. Owen to indicate an approach
to the carnivorous type, and this affinity he showed is further exhi-
bited in the specimen found by Mr. Fox, in the prolongation back-
ward of the angle of the jaw, a character which in the class Mam-
malia has hitherto been found almost exclusively in the carnivorous
order, and certainly in no Pachydermatous or other ungulate species
of Mammal. In the jaw from the Isle of Wight the angle is more
compressed and deeper than in the bear, dog, or cat tribe; and it is
not bent inwards in the way which peculiarly distinguishes the mar-
supial jaws, and which so neatly characterizes the Stonesfield mam-
miferous remains. ‘The condyloid process in the Cheeropotamus is
raised higher above the angle of the jaw than in the true Carnivora;
and it is less convex than in the hog or peccari; and the coronoid
process is more developed than in the peccari. In the wavy out-
line of the inferior border of the lower jaw, and in the teeth, which
are well developed in the jaw described by Mr. Owen, a close re-
semblance is displayed in the Cheropotamus to the peccari. The
jaw contains three true tuberculated molars and three conical false
molars with double fangs, which molars are relatively larger than
in existing Suidze, and an anterior tooth, which Cuvier in the Paris
basin specimens considered to be a canine, but which is situated
closer to the symphysis of the jaw than in any of the Suidz.

Mr. Owen then observed, that the occasional canine propensities
of the common hog are well known; and that they correspond with
the organization of the genus which offers the nearest resemblance
among the existing Pachydermata to the carnivorous type of struc-
ture. In the extinct Cheropotamus we have evidently another of
those beautiful examples in Paleontology of links tending to com-
plete a chain of affinities which the revolutions of the earth’s surs
face has interrupted, and for a time concealed from our view. It is
interesting also to perceive that the living sub-genus of the hog-tribe
which most resembles the Cheropotamus should be confined to the
South American continent, where the Tapir, the nearest living ana-
logue of the Anoplotherian and Palotherian associates of the Chze-
ropotamus, now exists.

The author then offered some remarks on a jaw discovered by
Mr. Pratt in the Binstead quarries in 1830, and considered by him
to be allied to the genus Moschus*. On comparing the jaw with
the corresponding part of the Moschus moschiferus, which it resem-
bles in size, Mr. Owen has found that in the fossil the grinders are
relatively broader, that the last molar has the third or posterior tu-
bercle divided by a longitudinal fissure, that the grinding surface is
less oblique, and that the coronoid process differs from that of the
Moschus and other ruminants, but strongly bespeaks an affinity with
the Pachydermata.

Among the genera of the Paris basin established by Cuvier, the
Dichobune exhibits characters which connect the Pachydermata with

* Geological Transactions, Sec. Ser. vol. iii. p. 451.

Phil. Mag. 8. 3, Vol. 14. No. 85. Jan. 1839. E

50 Geological Society.

the Ruminantia, and thus exhibits another of those extraordinary
unions of characters which in existing mammalia belong to distinct
orders. In the Dichobune the posterior molars begin to exhibit a
double series of cusps, of which the external present the crescentic
form, so that the teeth of the Dichobune murina might be mistaken
for those of true Ruminantia. In the lower jaw of the Dichobune
the antepenultimate and the penultimate grinders have two pairs of
cusps, and last grinder three pairs, of which the posterior are small
and almost blended together, so that when worn down they appear
single. ' ‘

In this respect, as well as in the form of the ascending ramus of
the lower jaw, Cuvier states, in the Ossemens Fossiles, that the Dicho-
bune “ prodigiously resembles” the young Musk Deer.

Now with respect to Mr. Pratt’s specimen, Professor Owen ob-
served, there is undoubtedly a close resemblance to the Musk Deer,
but the differences are sufficiently great to forbid its being placed
among the Ruminantia, while there is a still nearer resemblance be-
tween it and the genus Dichobune. The Isle of Wight specimen being
somewhat larger than the D. leporinum, and the ascending ramus
differing in form and approaching that of the true Anoplotheria, Mr.
Owen considers that it indicates a new species, which until the form
of the anterior molars and incisors are known, may be referred to the
genus Dichobune, under the name of Dichobune cervinum.

A memoir on the drift from the chalk and strata below the chalk
in the counties of Norfolk, Suffolk, Essex, Cambridge, Huntingdon,
Bedford, Hertford, and Middlesex, by James Mitchell, Esq., LL.D.,
F.G.S., was then read.

The drift which is so extensively distributed over the above coun-
ties, consists chiefly of stiff blue and yellow clay, varying from 4 feet
to above 70 in thickness ; and it contains masses and small fragments
of chalk, chalk flints, primary, secondary and other rocks, and fossils
from nearly every secondary formation in England. In some local-
ities the clay forms the mass of the drift, but in others it contains
or rests on beds of sand and gravel; and it is often overlaid by a
deposit, occasionally exceeding 50 feet thick, of sand, gravel, and
chalk flints.

The principal locality in Norfolk, mentioned by the author, is
Cromer, the cliffs near which vary in height from 100 to 150 feet ;
the lower half consisting of blue clay charged with masses and frag-
ments of chalk, unaltered chalk flints, and secondary and primary
rocks ; and the upper half of sand and gravel, capped by 2 feet of
ferruginous sand, in some places black. ‘The same general descrip-
tion, it is stated, will apply to the cliffs for 12 miles east and west
of Cromer; but they occasionally present most extraordinary con-
tortions of the beds. The other localities in Norfolk, alluded to
by the author, are in the parishes of Pulham St. Mary Magdalen,
Pulham St. Mary the Virgin; and a pit one mile from Harleston
towards Diss, where 4 feet of blue clay, abounding with chalk peb-
bles, are overlaid by 2 feet and underlaid by 10 feet of gravel and
flints; the author also states, that the clay with chalk pebbles ex-

Geological Society. 51

tends between Harleston and Diss, the latter town and North Lop-
ham, and thence to Norwich, Dereham, and Swaffham. In Suffolk
it was examined by him at Lowestoff, particularly in the cliff on
the north side of the town, where he obtained the following section:

Mavered Bopeig dissing ia S68) 4913 Od: rece «was 615 feet.
Miagk, sands i siba'y oe re these a op Host ietel aks 1 —
ed aud. yellow. eandiias ss ivd) sian aae atasieale our 15 —
Blue clay, with fragments of chalk, chalk flints, | Tories
Oolibe, GAG, TAS io, jini oan thes beets Bs. 8 oteiane orks Set
Redan yellow-sand, .3,,-4 wyid «sod sd. 2 hadla; Saree 2—
Covered slope ......... LD eworteogs aibeaNe otue 20 —
65

In the sea cliff a quarter of a mile north of Southwold, in Suffolk, the
clay contains a bed of sand two feet thick ; in the same county he like-
wise noticed it near Woodbridge, between Wrentham and Wangford,
and near the road from Wangford to Southwold. ‘The localities in
Essex mentioned by the author are Maldon, Kelvedon, Braintree,
Castle Heddingham near Halstead, Navestock, and Upminster; in
Cambridgeshire, Ely and between Caxton and Arrington ; inHunting-
donshire, the districts between Huntingdon and Peterborcugh and
Huntingdon and Caxton; in Bedfordshire, Castle Hill, 6 miles east
of Bedford; in Buckinghamshire, the line of the London and Bir-
mingham railway, near Fenny Stratford and Leighton Buzzard,
where it rests on the lower greensand, and is overlaid by gravel
containing rounded fragments of ferruginous sandstone; in Middle-
sex the only localities mentioned are Finchley and Muswell Hill; in
Hertfordshire the clay was not noticed by the author, though the
gravel abounds with fragments of secondary and other formations.

A description is then given of the transported rocks either inclosed
in the clay or accumulated in beds of gravel. They consist of hard
and soft chalk, flints, oolite, cornbrash, lias, sandstones, mountain
limestone, mica slate, trap, granite, syenite, porphyry, &c. The
principal localities mentioned are the Stags Inn near Diss, the Holy-
well and Witlingham near Norwich, Ballingdon Hill near Sudbury;
between Peterborough and Huntingdon and thence to Caxton, also
between that place and Arrington; in Hertfordshire these accumu-
lations are said to abound around Buntingford, Hare Street, Puck-
eridge, Much Haddam, and Newnham near Baldock : a few specimens
occur around Hertford and at Ware Mill, and Wade’s Mill, 13 miles
from Ware. ‘The pits at Muswell are particularly noticed, and the
collections from them formed by Mr. Wetherell and Mr. Frederick
Pusey ; but the specimens of rocks are said to be not nearly so nu-
merous, nor the size of the masses so great as in Hertfordshire, Hun-
tingdonshire, Suffolk, and Norfolk.

Besides the smaller fragments two large boulders are described.
One consisting of granite and computed to weigh a ton and a half,
lies by the road side on the north of the village of Hare Street ; and
it is so thoroughly rounded that the author had great difficulty in

E 2

Lod

52 Royal Society.

detaching a fragment. The other boulder occurs at Baldock, and
consists of hard chalk containing common black flints. It is about
3 feet 9 inches high above ground, 24 feet long, and nearly 2 feet
broad.

The current by which the drift was accumulated, the author con-
ceives came from a point to the east of north, and he is of opinion
that the materials have been derived in part from Scandinavia and
in part from the destruction of strata, which once occupied the site
of the German Ocean. After the deposition of the clay, Dr. Mitchell
believes, that there was a violent action which accumulated the beds
of gravel in some places to the depth of above 100 feet (Beaumont
Green, 110 feet; the Isle of Dogs, 124 feet); and that this action
will account for the clay not being found in more places, and being
occasionally associated with beds of gravel.

The paper concludes with a slight allusion to a similar north-east
drift, north of the counties enumerated in the title; and it is stated
that grey quartz boulders continue to be thrown in at Spurn Head,
Yorkshire, similar to those which are found in some of the vales of
the counties of Lincoln, Nottingham, and Leicester. Fragments of
mountain limestone, lias, oolite, grey quartz, white quartz, and hard
chalk are said to occur about Mount Sorrell.

ROYAL SOCIETY.
[Continued from vol. xiii. p. 467.]

November 15, 1838.—A paper was read, entitled, ‘‘ Discovery of
the Source of the Oxus.”’ By Lieut. Wood, of the Indian Navy..
Communicated by James Burnes, K.H., D.C.L., F.R.S., in a letter
to the Secretary of the Royal Society.

The following notice of the discovery of the source of the Oxus
by Lieut. Wood, one of the officers serving under Captain Alex-
ander Burnes, F.R.S., in his political and scientific mission to Cabul,
is contained in a letter from Captain Burnes :

«This celebrated river’ (the Oxus) “rises in the elevated region
of Pameer in Sinkoal. It issues from a sheet of water, encircled on
all sides, except the west, by hills, through which the infant river
runs ; commencing its course at the great elevation of about 15,600
feet above the level of the sea, or within a few feet of the height of
Mont Blanc. To this sheet of water Lieut. Wood proposes to as-
sign the name of Lake Victoria, in honour of Her Majesty.”’

November 22, 1838.—A paper was read, entitled, ‘‘ On the State
of the Interior of the Earth.’ By W. Hopkins, Esq., M.A., F.R.S.,
F.R.A.S., &c.

The object of the present memoir is to inquire into the modes in
which the refrigeration of the earth may have taken place, on the
hypothesis that its entire mass was originally in a fluid state; an
hypothesis which was at first founded on astronomical considera-
tions, and is now corroborated by the discoveries of modern geology,
exhibiting the apparent injection from below of large masses of un-
stratified rocks, through the fissures of sedimentary strata. As-

Anniversary Address of H.R. H. the late President. 58

suming that this state of fluidity was the effect of heat, we are led
to consider the steps of transition by which the earth has passed into
its present state of solidity, and apparently permanent temperature.
After adverting to the analytical investigations of Fourier and Poisson
on this subject, the author proceeds to inquire into the results of the
laws of refrigeration of heated bodies, which may be conceived to
operate in the present case; namely, refrigeration by circulation,
which obtains when the fluidity is perfect, and that by conduction,
when the particles of the mass, by the diminution of fluidity, no
longer retain that mobility among one another which is requisite
for their circulation. ‘Thus while, in either case, the superficial
parts of the earth would rapidly cool and solidify by the radiation
of their heat into sidereal space, forming a crust of small thickness
compared with the whole radius of the globe, the internal mass may
be in one or other of the three following conditions :—First, it may
consist of matter still in a state of fusion, of which both the tem-
perature and the fluidity are greatest at the centre, but which has
been brought, by the long-continued process of circulation, ito a
state no longer admitting of this process, and capable, therefore, of
cooling only by conduction. Secondly, the earth may consist of
an external shell, of a central nucleus, rendered solid by the enor-
mous pressure to which it is subjected, and of an intermediate
stratum of matter in a state of fusion. The thickness of the shell,
as well as the radius of the solid nucleus, may possibly be small
compared with the radius of the earth. The fluidity of the inter-
vening mass must necessarily be here, also, considerably more im-
perfect than that which would just admit of cooling by circulation,
Thirdly, the earth may be solid from the surface to the centre.

The author then shows that the direct investigation of the manner
in which the earth has been cooled, assuming its original fluidity
from heat, cannot determine the actual condition of its central
parts, not from any imperfection in the analytical process, but from
the want of the experimental determination of certain values, which
it is extremely difficult, if not impossible, accurately to obtain. It
has occurred to the author that a more indirect test of the truth of
the hypothesis of the central fluidity of the earth might be found in
the delicate but well-defined phenomena of precession and nutation.
The investigation of the problems thus suggested is reserved by the
author for the subject of a future memoir.

Anniversary, November 30, 1838.—The lists of Fellows deceased,
and of Fellows admitted since the last Anniversary having been
read, it was stated that the report of the death of R. Z. Mudge, Capt.
K.E., noticed at the last Anniversary, has been since found to be
erroneous.

The following Address of His Royal Highness the President was
read from the Chair:

GENTLEMEN,
I cannor quit the Chair of the Royal Society, which I have now
occupied during a period of eight years, without availing myself of
the opportunity which the customary proceedings of the Anniver-

54 Royal Society.

sary afford me, of expressing to you the grateful sense I entertain
of the great honour conferred upon me, by being chosen to fill so
distinguished an office, as likewise of the uniform kindness and
support which I have always received from the Members of the
Council and the Fellows of the Society generally, in the discharge
of its various and important duties.

A review of my conduct during the period of my Presidency, re-
calls to my mind many occasions in which I am sensible that I have
been more or less wanting in the very responsible trust confided to
me, of watching over the interests of a Society most justly illustrious
by the succession of great men who have been connected with it
and by the great advances which nearly every department of science
has received from those portions of their labours which are recorded
in its Transactions ; for some of these deficiencies I am unfortunately
enabled to refer to the severe and long continued visitations of dis-
ease and infirmity under which I have laboured, as a very sufficient
apology ; and I feel less oppressed than I otherwise should have been,
by my consciousness of many others, by my knowledge of the ac-
tivity and zeal of the very able and efficient officers upon whom the
temporary discharge of my duties devolved, and from the assurance
which I felt, that the interests of the Society, when entrusted to
their care, would suffer no detriment by my absence.

Though justly proud of the distinction of presiding over the Royal
Society, and most anxious to promote, to the utmost of my power,
the great objects for which it was founded, I no sooner ascer-
tained that circumstances would probably, for a time, interfere with
my residence in London, during a considerable part of its An-
nual Session, and prevent my receiving its Members in a manner
compatible with my rank and position in this country, than I deter-
mined to retire from an office whose duties I could no longer flatter
myself as likely to be able to discharge in a manner answerable to
their expectations, or in accordance with.my own feelings. Having
come to this conclusion after the most anxious and painful consi-
deration, I deemed it due to the Members of the Council, in the first
instance, and next to the Fellows, to make it speedily and generally
known, with the view of enabling them to look out for a proper per-
son to fill a situation of such dignity in the scientific world, and
whose occupation could not fail to be an object of honourable am-
bition to men of the most eminent social rank, as well as of the most
distinguished scientific attainments.

I will not attempt to disguise from you, Gentlemen, the feelings of
deep and poignant regret I experienced upon taking a step that
would thus necessarily abridge the opportunities, which I had as
much enjoyed as J had highly prized, of being brought officially
into frequent and familiar contact with the most distinguished
philosophers of my own or other countries, and of employing
whatever influence my station in society enabled me to exert in
advocating the just claims and interests of men of science, in pro-
moting the objects of their labours, in fostering and encouraging
their mutual co-operation and intercourse, and in endeavouring to

Anniversary Address of H. R. H. the late President. 55

soothe the violence of personal or national jealousies, whenever they
unfortunately existed, by bringing them together in social or other
meetings where the discussion of topics of irritation could be either
suppressed or controlled, and where imaginary prejudices would
disappear under the softening operation of reciprocal knowledge and
experience. But though deprived for a season, by my retirement, of
some of the highest privileges I have hitherto exercised and enjoyed,
yet I do not abandon the hope of being still able to maintain and
cultivate the very valuable and delightful friendships which I have
thus fortunately for myself been enabled to form during the period
of my connection with you, by seizing every occasion when pre-
sented to me, of appearing at the meetings of the Royal Society,
and by co-operating with its members, to the utmost extent of my
limited means, in furthering those objects that may be considered to
be most important for the advancement of the interests of science.

I am afraid however, Gentlemen, that I have already trespassed
unreasonably upon your time and attention in endeavouring to ex-
plain to you the motives of my conduct, and to express, though most
inadequately, my grateful sense of the kindness which I have inva-
riably experienced from you. I shall therefore now proceed to the
more immediate subject of this Address, which is to notice some of
the most important Proceedings of the Society which have taken
place during the last year.

The Address voted to Her Majesty by the President and Council
of the Royal Society, on the Queen’s accession to the throne, em-
bodying likewise « petition to Her Majesty to become the Patron
of the Society, and to continue to it the Grant of the Medals which
had been instituted by King George the Fourth and regranted
by William the Fourth, as well as the gracious reply of the Sove-
reign, transmitted through the Secretary of State for the Home
Department, have been already communicated to you at one of the
weekly meetings of the Society*. On the 20th of June last, the
President and Council were summoned to attend at the Palace of
St. James’s to witness Her Majesty’s signature in our Charter-Book
as Patron of the Society. I availed myself of the occasion thus
presented to me to address the Queen in your name, and to assure
Her Majesty that we felt bound by the obligations of our Charter,
as well as by the recollection of our foundation, to look up to the
Sovereign of these realms as our Patron and protector: that we
most gratefully acknowledged the assurances which Her Majesty
had conveyed to us through Her minister the Secretary of State for
the Home Department, of the continuance of the same support and
favour as had been always accorded to us by the Sovereigns of
this Kingdom, and likewise the signification of Her Majesty’s in-
tention of renewing the grant of the two Medals which had been in-
stituted by one and confirmed by another of Her Majesty’s royal
uncles and predecessors, accompanied by Her gracious permission
to propose such modification and amendments in the statutes which

* June 21, 1838.

56 Royal Society.

had been provided for their distribution, as would tend most effect-
ually to promote the advancement of science, and would most
certainly accomplish the liberal and patriotic views and intentions
of their Royal Founders. I further ventured to advert to the close
connection which exists between the cultivation of Science and
the Arts, and the progress and developement of the great elements
of the prosperity and happiness of nations, and to express my
earnest hope and prayer that the triumphs of the arts of peace and
commerce, which had so signally marked the beginning of Her
Majesty’s reign, might be continued without intermission to its
distant conclusion.

The Queen having received the Address in the most gracious
manner, was pleased to sign her august and royal name in our
Charter-Book as Patron of the Royal Society: after which the
officers and different members of the Council were presented by
me to Her Majesty, and had the honour of kissing Her Majesty’s
hand.

The alterations in the laws for the distribution of the Royal Me-
dals, which Her Majesty was graciously pleased to authorize and
permit, have been made by a Committee of the Council appointed
for that purpose, and have since received the especial sanction
and approbation of Her Majesty. ‘They are directed to be given
hereafter to such papers, and to such papers only, as have been
presented to the Society, or inserted in its Transactions, within
three years of the date of the award; and they are to be awarded
to departments of science whose order of succession is defined by a
cycle of three years, comprising in the first Astronomy and Physi-
ology, in the second Physies and Geology, and in the third Mathe-
matics and Chemistry. And it is further added and commanded,
that no departure from this order of succession shall be allowed,
unless it shall appear that no memoir of sufficient merit to be en-
titled to such an honour shall have been presented to the Society
within the period afore-named; in which case, and in which case
only, it shall be competent for the Council, with the approbation
of Her Majesty, to award the Medal to one of those branches
of science which are comprehended in the cycle of the preceding
year.

; I trust, Gentlemen, that these laws for the distribution of the
Royal Medals, if strictly adhered to, and judiciously administered,
will be found to stimulate the exertions of men of science, by se-
curing to their labours, when inserted in our Transactions, that eer-
tain and periodical revision which they are naturally so anxious to
obtain ; and by signalizing any remarkable investigation, or notable
discovery, by the marked and pronipt approbation of those persons
in this country who are most likely to be able to judge of its value.

It was partly for the furtherance of the same great object, which
was proposed in framing the statutes for the award of the Royal
Medals, so as to secure to each branch of science in succession its
due amount of notice and encouragement, that the Council have
determined to establish permanent Committees of Science. They

Anniversary Address of H. R. H. the late President. 57

are composed of a selection of those Fellows of the Society who
are known to have devoted their attention, in a more especial man-
ner, to those departments of science to which they are severally
assigned, and to whom all questions connected with such branches
are proposed to be referred, including the selection of the memoirs
to which the Royal Medals shall be given. The Council have
thought proper, likewise, in the formation of these committees, to
enlarge the number of the sciences, which form the Medallic cycle
above referred to, from six to eight, by separating the science of
Meteorology from that of Physics, and the science of Botany and
the laws of Vegetable Organization and Life, from that of Zoology
and Animal Physiology. I sincerely rejoice, Gentlemen, in the
adoption of this arrangement, as I think it admirably calculated to
give a more marked and specific distinction to those sciences which
the Fellows of the Royal Society are bound more especially, by the
obligations of the Charter, to cultivate, and as tending, likewise, to
bring those persons who are engaged in common pursuits into more
frequent intercourse with each other; and thus to afford them in-
creased opportunities of appreciating their mutual labours, of de-
vising new and important trains of investigation, as well as of se-
curing public aid and general co-operation in the accomplishment
of objects which are too costly or too vast for individuals to under-
take or to attempt. :

The future developement of many of the sciences is becoming
daily more and more dependent upon co-operative labour. We are
rapidly approaching great and comprehensive generalizations, which
can only be completely established or disproved by very widely
distributed and, in many cases, by absolutely simultaneous observa-
tions. Major Sabine has lately collected with great labour, and re-
duced and analysed with great ability, a vast mass of observations
relating to the distribution of the earth’s magnetism ; and the result
has pointed out not merely the proper fields of our future researches,
but likewise their great extent and the enormous amount of labour
still required for their cultivation. A society on the continent, headed
by the justly celebrated Gauss, to whom the Copley Medal has been
this year adjudged for his magnetical researches, my cotemporary and
fellow student at Gottingen, has instituted a system of simultaneous
observations on the periodical and irregular movements of the mag-
netic needle at various stations in different parts of Europe, which
suggest conclusions of the most surprising and interesting nature ;
these can only be fully worked out and confirmed by the adoption
of a similar system of observations in places extremely remote from
each other on the surface of the globe, The researches on the tides,
which have been so laboriously and so successfully prosecuted by
Professor Whewell and Mr. Lubbock, have led, and can lead to few
general and certain conclusions without the aid of labours of this
nature ; and a memorable exemplification of their value, even when
given in their rudest and least perfect form®, is presented in the

* From the logs of ships.

58 Royal Society.

discovery of the “ Law of Storms,” which Col. Reid has recently
published, and which promises results so important to the interests
of navigation and the cause of humanity. In the science of Mete-
orology, which still remains destitute even of approximations to ge-
neral laws, it is to a well-organized system of simultaneous observa-
tions that we must look for the acquisition of such a knowledge of
the range and character of atmospheric influences and changes, as
may become the basis of a well-compacted and consistent theory,
and rescue this science from the reproach, under which it has too
long and too justly laboured, of presenting little more than a con-
fused mass of almost entirely insulated results. Undertakings, how-
ever, of this extensive and laborious nature are far beyond the
reach of individual enterprize, and can only be accomplished by
national aid and co-operation.

We have lately witnessed an example where the Storthing, or
National Assembly of Norway, a body composed partly of peasants,
and representing one of the poorest countries in Europe, undertook
the charge of a magnetical expedition to Siberia, on the recom-
mendation and under the direction of their distinguished country-
man, M. Hansteen, at the same time that they refused a grant of
money to aid in building a palace for their sovereign; and I feel
confident that the united wishes of men of science in this and
other countries, whose influence on public opinion is becoming
daily more and more manifest, particularly when expressed in favour
of purely scientific objects which cannot be effected without the as-
sistance and the resources of the nation, will not be without their
effect on the Government of our own country, which has always
taken the lead in the promotion of geographical as well as scientific
investigations and discoveries, and which possesses, beyond any other
nation, advantages for their prosecution and accomplishment, not
merely from its superior wealth, but from the range and distribution
of its commerce and its colonies in every region of the globe.

There is one other event to which I wish to advert previously to
concluding this portion cf my address to you, and which I conceive
I may do with the strictest propriety, as it is closely connected with
the general interests of the Royal Society. I allude to the return of
Sir John Herschel to this country, after an absence of several years,
devoted, from a sense of filial duty, to the completion of that great
task which he felt to have been transmitted to him as an inheritance
from his venerable and illustrious father. I have so often had oc-
casion to allude, from this Chair, to the merits of that distinguished
person, and to express the respect which I felt for his great attaiu-
ments, the pride with which I cherished his friendship, the deep in-
terest which I took in his labours, and my admiration of the truly
modest and philesophical spirit in which they were conducted, that
I should be guilty of a very superfluous repetition of what I have
before addressed to you, if I ventured to enlarge upon them now;
but I should ill discharge my duty, whilst still entitled to address
you as the official head of the scientific establishment of this coun-
try, if I omitted to avail myself of this or any other opportunity of

Anniversary Address of H. R. H. the late President. 59

expressing the gratification which I experienced in June last, when
called upon to preside at that great convention of the most eminent
men who adorn our country, who combined together with such sin-
gular unanimity and enthusiasm to pay their homage to science and
knowledge, and those great interests with which their cultivation
and progress are connected, by paying so signal a tribute of respect
and honour to the most accomplished and the most devoted of our
living philosophers. I feel assured, Gentlemen, that the proceed-
ings of that memorable day will produce marked and durable ef-
fects upon the scientific prospects of our country, by proving that
pre-eminent merit will meet with sympathy at least, if not with re-
ward, and as offering sure and unequivocal indications both of the
power and direction of public opinion amongst the most cultivated
and enlightened classes of society; and it was chiefly as an expres-
sion of the deference paid by the government of this country to the
opinions and wishes of the scientitic world, that 1 rejoiced in being
authorized and requested by the prime minister of the crown to
offer to Sir John Herschel the rank of baronet, on the occasion of
the coronation of Her Majesty, though well convinced that such an
accession of social rank was not required to give dignity to one
whose name is written in the imperishable records of the great sy-
stem of the universe.

It would ill become me, while gratefully acknowledging my sense
of your past kindnesses towards myself, to venture to refer to the
name of my presumed successor in the Chair of this Society in any
terms which might be interpreted as an undue anticipation of the
result of this day’s proceedings, or as appearing to interfere with the
free use of the franchise which every Fellow possesses, and is ex-
pected and required to exercise ; but I cannot be ignorant of the
various accomplishments, the courteous and unassuming manners,
the warmth of heart and active benevolence which distinguish the
nobleman who has been nominated by the Council: and I rejoice
most sincerely that the Society possesses amongst its members, as a
candidate for your suffrages, one so well qualified to preside at your
meetings, and to watch over your interests.

Amongst the deceased members, I find twenty-seven on the
Home, and four on the Foreign list, including some very consider-
able names. I shall now proceed to notice such of their number
as have been most distinguished for their scientific labours, for their
public services, or for their encouragement and patronage of science
and the arts.

Thomas Andrew Knight, of Downton Castle, Herefordshire, the
President of the Horticultural Society of London, to the establish-
ment and success of which he so greatly contributed, was born in the
year 1758. He was educated at Ludlow school, and afterwards be-
came a member of Balliol College, Oxford. From his earliest years
he appears to have shown a predominant taste for experimental
researches in gardening and vegetable physiology, which the imme-
diate and uncontrolled possession of an ample fortune gave him
every opportunity of indulging ; proposing to himself in fact, as one

60 Royal Society.

of the great objects of his life, to effect improvements in the pro-
ductions of the vegetable kingdom, by new modes of culture, by the
impregnation of different varieties of the same species, and various
other expedients, commensurate with those which had already been
effected by agriculturists and others in the animal kingdom, by a
careful selection of parents, by judicious crossing, and by the avoid-
ance of too close an alliance of breeds. In the year 1795 he contri-
buted to our Transactions his first, and perhaps his most important
paper, on the transmission of the diseases of decay and old age of
the parent-tree to all its descendants propagated by grafting or
layers, being the result of experiments which had already been long
continued and very extensively varied, and which developed views
of the greatest importance and novelty in the economy of practical
gardening, and likewise of very great interest in vegetable physio-
logy. This paper was succeeded by more than twenty others,
chiefly written between the years 1799 and 1812, containing the de-
tails of his most ingenious and original experimental researches on
the ascent and descent of the sap in trees; on the origin and offices
of the alburnum and bark ; on the phenomena of germination ; on the
functions of leaves; on the influence of light, and upon many other
subjects, constituting a series of facts and of deductions from them,
which have exercised the most marked influence upon the progress
of our knowledge of this most important department of the laws of
vegetable organization and life.

Mr. Knight succeeded Sir Joseph Banks in the presidency of the
Horticultural Society, and contributed no fewer than 114 papers
to the different volumes of its Transactions: these contributions
embrace almost every variety of subject connected with Horti-
culture; such as the production of new and improved varieties
of fruits and vegetables; the adoption of new modes of grafting,
planting, and training fruit-trees ; the construction of forcing-frames
and hot-houses; the economy of bees, and many other questions
of practical gardening, presenting the most important results of his
very numerous and well-devised experiments.

Mr. Knight was a person of great activity of body and mind,
and of singular perseverance and energy in the pursuit of his fa-
vourite science: he was a very lucid and agreeable writer, and it
would be difficult to name any other cotemporary author in this
or other countries who has made such important additions to our
knowledge of horticulture and the economy of vegetation.

Sir Richard Colt Hoare, the owner of the beautiful domain of
Stourhead in Wiltshire, was the author of many valuable historical
and topographical works, and more especially of the history of his
native county, presenting so numerous and such splendid funereal
and other monuments of the primitive inhabitants of Great Britain,
which he investigated with a perseverance and success unrivalled
by any other antiquary. The early possession of an ample fortune
and of all the luxuries of his noble residence, seems to have stimu-
lated, rather than checked, the more ardent pursuit of those favourite
studies, which occupied his almost exclusive attention for more than.

Anniversary Address of H. R. H. the late President. 61

fifty years of his life: and he was at all times, both by his co-operation
and patronage, ready to aid other labourers in the same field which
he had himself cultivated with so much success and industry.

Sir Richard Hoare was a very voluminous original author, and on
a great variety of subjects; he printed a catalogue of his unique
collection of books relating to the history and topography of Italy,
the whole of which he presented to the British Museum, to which
he was, on other occasions, a liberal benefactor. He likewise pub-
lished editions of many of our ancient chronicles ; and it is only
to be lamented that one who has contributed under so many forms
to our knowledge of antiquity, and who presents so many claims
to the grateful commemoration of the friends of literature and the
arts, should have been influenced so much, and so frequently, by
the very unhappy ambition, of which some well-known and di-
stinguished literary bodies of our own time have set so unworthy
an example, of giving an artificial value to their publications, by the
extreme smallness of the number of copies which they allow to be
printed or circulated ; thus defeating the very objects of that great
invention, whose triumphs were pretended to be the very ground-
work of their association.

Mr. George Hibbert was one of the most distinguished of those
princely merchants, whose knowledge of literature, patronage of the
arts, and extensive intercourse with the world have contributed so
much, in a great commercial country like our own, to elevate the
rank and character of the class to which they belong, and to give to
the pursuits of wealth an enlarged and liberalizing spirit. Mr. Hib-
bert possessed, during the most active period of his life, an uncom-
mon influence amongst the great commercial bodies of the me-
tropolis, and more particularly amongst those connected with the
West India trade, from his integrity and high character, his great
knowledge of business, his excellent sense and judgement, and his
clearness and readiness in public speaking. He was an excellent bo-
tanist, and the collection of plants which he had formed at his resi-
dence at Clapham, was remarkable not merely for its great extent, but
likewise for the great number of extremely rare plants which it con-
tained. He was well known also as a very extensive and judicious
collector of books, prints, drawings and paintings, and was endeared
to alarge circle of private friends, amongst the most cultivated classes
of society in this country, by his refined yet simple manners, his
happy temper, and his many social and domestic virtues.

Sir Abraham Hume, who had attained at the time of his death
the venerable age of ninety years, was the father of the Royal So-
ciety ; he was a man of cultivated taste and very extensive ac-
quirements, and throughout his life a liberal patron and encourager
of the fine arts.

Lord Farnborough was the son-in-law of Sir Abraham Hume,
whom he greatly resembled in his tastes and accomplishments ; for
more than thirty years of his life he held various public situations
in the successive administrations of this country, but quitted his
official employments on his elevation to the peerage in 1826:

62 Royal Society.

from that period he devoted himself almost entirely to the improve-
ment and decoration of his beautiful residence at Bromley Hill; to
the proposal and promotion of plans for the architectural improve-
ment of the metropolis ; to the selection of pictures for the National
Gallery, which he greatly enriched by his bequests ; and to the va-
rious duties imposed upon him by his official connexion with the
British Museum, and many other public institutions.

The Earl of Eldon, though possessing few relations with science
or literature, presents too remarkable an example of the openings
afforded by the institutions of this country to men of great and com-
manding talents for the attainment of the highest rank and wealth,
to be passed over without notice in this obituary of our deceased
Fellows. Lord Eldon was matriculated as a member of University
College, Oxford, under the tuition of his brother, afterwards Lord
Stowell, in 1766; and an academical prize which he gained in the
following year, for an “ Essay ou the Advantages of Foreign Tra-~
vel,” gave the first evidence of his possession of those great powers
of minute analysis and careful research, which made him afterwards
so celebrated. His early marriage terminated somewhat prematurely
his academical prospects, and forced him to adopt the profession of
the law, after narrowly escaping other occupations of a much more
humble character. He was compelled to struggle for several years of
his life with poverty and discouragement, when afortunate opportunity
enabled him to give proof of his extraordinary attainments, and ra-
pidly conducted him to the command of wealth and professional emi-
nence. After filling with great distinction the offices of Solicitor and
Attorney-General, he became Chief-Justice of the Common Pleas and
a peer in 1799, and finally Lord Chancellor of England in 1801, a
situation which he continued to hold, with a short interruption, for
nearly a quarter of a century. Of his political character and con-
duct it becomes not me to speak; but his profound knowledge of
the laws of England, his unrivaled acuteness and sagacity, and his
verfect impartiality and love of justice, have received the concur-
rent acknowledgment and admiration of men of all parties.

The Rev. Thomas Catton, Senior Fellow of St. John’s College,
Cambridge, was in early life a schoolfellow of Lord Nelson, of whose
talents or character, however, he retained no very vivid impressions :
he became a Member of the University in 1777, and when he took
his degree in 1781 he was fourth Wrangler and first Smith’s Prize-
man, a discrepancy in the results of two similar examinations, which
is said to have led to the adoption of some regulations prevent-
ing their recurrence in future. In the year 1800 he became one
of the public tutors of his college, in conjunction with its pre-
sent venerable and distinguished master, and secured, in a very
uncommon degree, the respect and love of his pupils, by his skill
and knowledge as a teacher, and by his kind and vigilant attention
to their interests: he quitted the tuition in 1810, and for the re-
mainder of his life he devoted himself, almost exclusively, to the
cultivation of practical and theoretical astronomy, having succeeded
to Mr, Ludlam in the management of the observatory which is

Anniversary Address of H. R. H. the late President. 63

placed over one of the interior gateways of the college. He possessed
a most accurate knowledge of the theory and use of astronomical
instruments, and was a most scrupulous and skilful observer ; and he
is known to have left behind a very large mass of observations, par-
ticularly of occultations, most carefully detailed and recorded. Mr.
Catton was a man of very courteous manners and most amiable
character, and possessed of a very extensive acquaintance both with
literature and science. He died in the month of January last, in the
eightieth year of his age, deeply regretted by the members of the
college in which he had passed the greatest part of his life.

Mr. Henry Earle, one of the Senior Surgeons of St. Bartholomew’s
Hospital, was the son of one very eminent surgeon, Sir James Earle,
and the grandson of another, Mr. Percival Pott. He was the author
of many valuable articles in different medical journals, and likewise
of two papers in our Transactions; one detailing the result of a
very novel and difficult surgical operation, and the other on the
mechanism of the spine, which were published in 1822 and 1823.
Mr. Earle was considered to be one of the most skilful and scien-
tific surgeons of his age, and was justly esteemed by his professional
and other friends not merely for his great acquirements, but for his
kindness of heart and upright and honourable character.

John Lloyd Williams, formerly British resident at Benares, was
the author of three short papers in our Transactions in the year
1793; two of them upon the method of making ice at Benares, by
means of extremely porous and shallow evaporating pans of unglazed
earthenware, placed upon dry straw or sugar-cane ; and the last fur-
nishing additional descriptions of the great quadrants and gnomon
in the observatory at Benares, which had been described in a paper
in our Transactions in 1777 by Sir Robert Barker.

The Foreign Members whom the Society has lost during the last
year, are Dr. Nathaniel Bowditch, of Boston, in America ; Messieurs
Dulong and Frederic Cuvier, of Paris ; and Dr. Martin van Marum,
of Haarlem.

Dr. Nathaniel Bowditch of Boston, in the State of Massachusetts
in America, was born at Salem, in the same State, in 1773: he was
removed from school at the age of ten years to assist his father in
his trade as a cooper, and was indebted for all his subsequent acqui-
sitions, including the Latin and some modern languages and a pro-
found knowledge of mathematics and astronomy, entirely to his own
exertions unaided by any instruction whatever. He became after-
wards a clerk to a ship-chandler, where his taste for astronomy first
showed itself, and was sufficiently advanced to enable him to master
the rules for the calculation of a lunar eclipse ; and his subsequent
oceupation as supercargo in a merchant vessel sailing from Salem
to the East Indies, led naturally to the further developement of
his early tastes, by the active and assiduous study of those depart-
ments of that great and comprehensive science which are most im-
mediately subservient to the purposes of navigation. It was owing
to the reputation which he had thus acquired for his great knowledge
of nautical astronomy, that he was employed by the booksellers to

64 Royal Society.

revise several successive editions of Hamilton Moore’s Practical
Navigator, which he afterwards replaced by an original work on
the same subject, remarkable for the clearness and conciseness of
its rules, for its numerous and comprehensive tables, the greatest
part of which he had himself recalculated and reframed, and for its
perfectly practical character as a manual of navigation: this work,
which has been republished in this country, has been for many years
almost exclusively used in the United States of America.

Dr. Bowditch having been early elected a Fellow of the American
Academy of Arts and Sciences at Boston, commenced the publica-
tion of a series of communications in the Memoirs of that Society,
which speedily established his reputation as one of the first astro-
nomers and mathematicians of America, and attracted likewise the
favourable notice of men of science in Europe.

During the last twenty years of his life, Dr. Bowditch was em-
ployed as ; the acting president of an Insurance Company at Salem, and
latterly also as actuary of the Massachusetts Hospital Life Insurance
Company at Boston: the income which he derived from these
employments, and from the savings of former years, enabled him to
abandon all other and more absorbing engagements, and to devote
his leisure hours entirely to scientific pursuits. In 1815 he began his
great work, the translation of the Mécanique Céleste of Laplace, the
fourth and last volume of which was not quite completed at the time of
his death. The American Academy over which he presided for many
years, at a very early period of the progress of this very extensive
and costly undertaking, very liberally offered to defray the expense of
printing it ; but he preferred to publish it from his own very limited
means, and to dedicate it as a splendid and durable monument of his
own labours and of the state of science in his country. He died in
March last, in the sixty-fifth year of his age, after a life of singular
usefulness and most laborious exertion, in the full enjoyment of
every honour which his grateful countrymen in every part of
America could pay to so distinguished a fellow-citizen.

Dr. Bowditch’s translation of the great work of Laplace is a pro-
duction of much labour and of no ordinary merit : every person who
is acquainted with the original must be aware of the great number
of steps in the demonstrations which are left unsupplied, in many
cases comprehending the entire processes which connect the enun-
ciation of the propositions with the conclusions, and the constant
reference which is made, both tacit and expressed, to results and
principles, both analytical and mechanical, which are co-extensive
with the entire range of known mathematical science: but in Dr.
Bowditch’s very elaborate commentary every deficient step is sup-
plied, every suppressed demonstration is introduced, every reference
explained and illustrated, and a work which the labours of an ordi-
nary life could hardly master, is rendered accessible to every reader
who is acquainted with the principles of the differential and inte-
gral calculus, and in possession of even an elementary knowledge
of statical and dynamical principles.

When we consider the circumstances of Dr. Bowditch’s early life,

Anniversary Address of H. R. H. the late President. 65

the obstacles which opposed his progress, the steady perseverance
with which he overcame them, and the courage with which he ven-
tured to expose the mysterious treasures of that sealed book, which
had hitherto only been approached by those whose way had been
cleared for them by a systematic and regular mathematical educa-
tion, we shall be fully justified in pronouncing him to have been a
most remarkable example of the pursuit of knowledge under dif_i-
culties, and well worthy of the enthusiastic respect and admiration
of his countrymen, whose triumphs in the fields of practical science
have fully equalled, if not surpassed, the noblest works of the ancient
world.

Pierre Louis Dulong was born at Paris in 1785: he became an
orphan at the age of four years; and though hardly possessing the
most ordinary advantages of domestic instruction or public education,
his premature talents and industry gained him admission at the age
of 16 to the Polytechnic School, which has been so fertile in the pro-
duction of great men, of which he became afterwards successively ex-
aminer, professor, and director. He first followed the profession of
medicine, which he abandoned on being appointed Professor of
Chemistry to the Faculty of Sciences. He became a member of the
Institute in 1823, in the Section of the physical sciences. On the
death of the elder Cuvier he was appointed Secretaire Perpetuel
to the Institute, a situation from which he was afterwards compelled
to retire by the pressure of those infirmities which terminated in
his death in the fifty-fourth year of his age.

M. Dulong was almost equally distinguished for his profound
knowledge of chemistry and of physical philosophy. His “ Re-
searches on the mutual decomposition of the soluble and insoluble
Salts,” form a most important contribution to our knowledge of che-
mical statics. He was the discoverer of the hypophosphorous acid,
and also of the chlorure of azote, the most dangerous of chemical
compounds, and his experiments upon it were prosecuted with a
courage nearly allied to rashness, which twice exposed his life to
serious danger ; and his memoirs on the “ Combinations of phospho-
rus with oxygen,” on the “hyponitrie acid,” on the oxalic acid,
and other subjects, are sufficient to establish his character as a most
ingenious and accurate experimenter, and as a chemical philosopher
of the highest order.

But it is to his researches on the “Law of the conduction of
heat,” “On the specific heat of the gases,” and “On the elastic
force of steam at high temperatures,” that his permanent fame as a
philosopher will rest most securely : the first of these inquiries, which
were undertaken in conjunction with the late M. Petit, was published
in 1817; and presents an admirable example of the combination of
well-directed and most laborious and patient experiment with most sa-
gacious and careful induction: these researches terminated, as is well
known, in the very important correction of the celebrated law of
conduction, which Newton had announced in the Principia, and
which Laplace, Poisson, and Fourier had taken as the basis of their
beautiful mathematical theories of the propagation of heat. His ex-

Phil. Mag. 8. 3, Vol. 14, No. 85. Jan, 18389. F

66 Royal Society.

periments on the elastic force of steam at high temperatures, and
which were full of danger and difficulty; were undertaken at the re-
quest of the Institute, and furnish results of the highest practical
value ; and though the conclusions deduced from his “ Researches
on the specific heat of gases” have not generally been admitted by
chemical and physical philosophers, the memoir which contains them
is replete with ingenious and novel speculations, which show a pro-
found knowledge and familiar command of almost every department
of physical science.

M. Frederic Cuvier, the younger brother of the illustrious Baron
Cuvier, Professor of Animal Physiology to the Museum of Natural
History at Paris, and Inspector-general of the University, was born
at Montbelliard, in Alsace, in 1773: he had from an early period
attached himself to those studies which his brother had cultivated
with so much success, and his appointment as keeper of the mena-
gerie at the Jardin des Plantes, furnished him with the most favour-
able opportunities of studying the habits of animals, and of prose-
cuting his researches on their physiology and structure. The An-
nales d'Histoire Naturelle, and the Mémoires du Muséum, contain a
series of his memoirs on zoological subjects of great value and in-
terest, and his work “Sar les Densdes Mammiferes considerées comme
Caractéres Zoologiques,” is full of novel and original views and ob-
servations, and has always been considered as one of the most va-
luable contributions to the science of Zoology which has been made
in later times: the great work “ Sur U Histoire des Mammiferes,” of
which seventy numbers have been published, was undertaken in con-
junction with Geoffroy St. Hilaire, and is the most considerable and
most extensive publication on Zoology which has appeared since
the time of Buffon. He was likewise the author of many other
works and memoirs on zoological subjects in various scientific jour-
nals and collections.

M. F. Cuvier, like his celebrated relative, combined a remarkable
dignity and elevation of character, with the most affectionate tem-
per and disposition. Like him, too, his acquisitions were not con-
fined to his professional pursuits, but comprehended a very exten-
sive range of literature and science. In his capacity of inspector
of the university, he devoted himself with extraordinary zeal to the
improvement of the national education of France in all its depart-
ments, from the highest to the lowest. It was in the course of one
of his tours of inspection that he was attacked at Strasburg with
paralysis; the same disease which, under siniilar circumstances, had
proved fatal to his brother, and likewise in the same year of his age.

Dr. Martin van Marum was secretary to the Batavian Society of
Sciences at Haarlem, and superintended the publication of their
Transactions for many years. He was also director of the Tey-
lerian Museum at the same place, and the noble library of natural
history and science which adorns that establishment was chiefly
collected by his exertions: it was under his directions also that the
great electrical machine belonging to the Teylerian Museum was
constructed, and he published in 1795 and 1800 the results of a

Astronomical Society. 67

very extensive series of experiments on the various forms of elec-
trical phenomena which were produced by it, and more particularly
with reference to a comparison of its effects with those produced
by a powerful voltaic pile, which were undertaken at the express
request of Volta himself. Dr. van Marum was remarkable for his
very various acquirements, and was the author of many memoirs in the
Haarlem and other Transactions, on botanical, chemical, physical, and
other subjects : he was a man of the most simple habits and of the most
amiable character, and devoted himself most zealously during the
greatest part of a very long life to the cultivation of science, and to
the promotion of the interests of the establishment over which he
presided.

Gentlemen, I have now arrived at the last and most painful part
of my duty in addressing you, which is most gratefully and most re-
spectfully to bid you farewell.

ASTRONOMICAL SOCIETY.

Nov. 9, 1838.—The following communications were read :—

I. Astronomical Observations made at the Imperial Observatory
at Wilna, in the year 1885. By M. Slavinski.

These observations are of a similar nature to those made in former
years, and communicated to the Society from time to time. The
present collection consists of observations of Jupiter, Saturn, Mars,
and Uranus, as well as of moon-culminating stars, occultations of
stars by the moon, and eclipses of Jupiter's satellites. The geo-
centric right ascension and declination of each planet, and for each
day of observation, are compared with the positions deduced from
Encke’s Berlin Ephemeris, and the differences noted. In the case
of Jupiter these differences in right ascension are all positive, and
the maximum difference is 15,36; in declination the maximum dif-
ferences are — 4!'-] and + 6”-9. In the case of Saturn, the differ-
ences are likewise (with one slight exception) all positive, the maxi-
mum being 0,80; the same remark applies to the declinations, the
whole of the differences being positive, and varying from 15'6 to
28-1. In the case of Mars, the differences in right ascension var
from —08,25 to +08,52; and in declination from —1!-9 to +176,
In the case of Uranus, the differences in right ascension are very
considerable, and all positive, varying from 38,07 to 48,02; but in
declination the differences are not so great, being confined within
—4'"9 and +3'-9, These large errors in the tables of some of the
planets are confirmed by observations made at other observatories ;
and will doubtless, in time, lead to their correction.

The observations of the moon-culminating stars were made on
thirty-two days at various parts of the year, each observation being
made with the five wires of the transit. Only six of these observa-
tions were made of the second limb of the moon.

The occultations are six in number; one being of Saturn on the
27th of August; and the others of various stars. There are ten
eclipses of Jupiier’s satellites ; viz. five of the first, and five of the
second. ‘I’o the whole is subjoined the monthly mean of the baro-

F 2

68 Astronomical Society.

meter and thermometer during the year, with a statement of the
prevailing wind, which appears to be north-west and south.

II. A letter from Professor Bessel to Sir J. Herschel, Bart., dated
Konigsberg, Oct. 23, 1838.

Esteemed Sir,—Having succeeded in obtaining a long-looked-for
result, and presuming that it will interest so great and zealous an
explorer of the heavens as yourself, I take the liberty of making a
communication to you thereupon. Should you consider this com-
munication of sufficient importance to lay before other friends of
Astronomy, I not only have no objection, but request you to do so.
With this view, I might have sent it to you through Mr. Baily; and
I should have preferred this course, as it would have interfered less
with the important affairs claiming your immediate attention on your
return to England. But to you I can write in my own language,
and thus secure my meaning from indistinctness.

After so many unsuccessful attempts to determine the parallax
of a fixed star, I thought it worth while to try what might be ac-
complished by means of the accuracy which my great Fraunhofer
heliometer gives to the observations. I undertook to make this
investigation upon the star 61 Cygni, which, by reason of its great
proper motion, is perhaps the best of all; which affords the advan-
tage of being a double star, and on that account may be observed
with greater accuracy ; and which is so near the pole that, with the
exception of a small part of the year, it can always be observed at
night at a sufficient distance from the horizon. I began the com-
parisons of this star in September 1834, by measuring its distance
from two small stars of the 11th magnitude, of which one precedes,
and the other is to the northward. But I soon perceived that the
atmosphere was seldom sufficiently favourable to allow of the ob-
servation of stars so small; and, therefore, I resolved to select
brighter ones, although somewhat more distant. In the year 1835,
researches on the length of the pendulum at Berlin took me away
for three months from the observatory; and when I returned, Halley’s
Comet had made its appearance, and claimed all the clear nights.
In 1836, I] was too much occupied with the calculations of the
measurement of a degree in this country, and with editing my work
on the subject, to be able to prosecute the observations of a Cygni
so uninterruptedly as was necessary, in my opinion, in order that
they might afford an unequivocal result. But, in 1837 these ob-
stacles were removed, and I thereupon resumed the hope that I
should be led to the same result which Struve grounded upon his
observations of a Lyre, by similar observations of 61 Cygni.

I selected among the small stars which surround that double
star, two between the 9th and 10th magnitudes; of which one (a)
is nearly perpendicular to the line of direction of the doubie star ;
the other (0) nearly in this direction. I have measured with the
heliometer the distances of these stars from the point which bisects
the distance between the two stars of 61 Cygni; as I considered this
kind of observation the most correct that could be obtained, I have
commonly repeated the observations sixteen times every night.

Prof. Bessel on the Parallax of the Star 61 Cygni. 69

When the atmosphere has been unusually unsteady, I have, however,
made more numerous repetitions ; although, by this, I fear the result
has not attaimed that precision which it would have possessed by
fewer observations on more favourable nights. This unsteadiness
of the atmosphere is the great obstacle which attaches to all the
more delicate astronomical observations. In an unfavourable cli-
mate we cannot avoid its prejudicial influence, unless by observing
only on the finest nights ; by which, however, it would become still
more difficult to collect the number of observations necessary for an
investigation. The places of both stars, referred to the middle point
of the double star, are for the beginning of 1838.

Distance. Angle of Pos.
a 461-617 201° 29! 24"
6 706 °279 109 22 10

As the instrument gives, at the same time, the distance and angle
of position, I have always observed both. But the position circle is
divided only into whole minutes; which, in the distance of the first
star, have the value of 0!'-134; in that of the second, 0/-205. More-
over, other causes exist which may render the observation of the
angle of position less certain than that of the distances. I have,
accordingly, considered the first of these as of less consequence in
so delicate an investigation, and concentrated my attention, as far as
I could, upon the latter.

The following tables [which will be found in the Monthly No-
tices of the Society, vol. iv. No. 17.] contain all my measures of di-
stance, freed from the effects of refraction and aberration, and re-
duced to the beginning of 1838. In these reductions, the annual va-
riations employed of both distances are = +4!"3915 and — 2!'825;
which I have deduced (on the supposition that the stars a and b
have no proper motions) from the mean motions of both stars of
61 Cygni, which M. Argelander had lately found by comparison of
my determination (from Bradley’s observations) for 1755, with his
own for 1830. In the meantime, we cannot regard these variations
of distance as the ¢rue variations; because the stars compared may
have proper motions, and, also, because it is not known whether the
mean of the motions of both stars of 61 Cygni appertains to its
centre, and whether this (motion) is proportional to the time. In
what follows, let us denote the true variations of the distances by
+4"°3915+4a! and —2'"825 + (!, the mean distances for the be-
ginning of 1835 by a and (3; the time, reckoned from this begin-
ning, by ¢; the difference of the constants of the annual parallax of
61 Cygni, and of the comparison-stars @ and 8, by «! and (3; and,
lastly, the coefficients of the parallax depending on the place of the
earth by a. Then the expressions of the distances at the beginning
of 1838 are—

For the stara=a+ta+aa'
For the star b = B + tf'+ ap!

These expressions, as they were at the time of each observation, I

70 Astronomical Society.

have written against the observations ; we can, therefore, by inspec-
tion, perceive how the observations agree with the theory.

If we compare both divisions of these tables, we shall perceive
that the agreement of the observations with each other is consider-
ably augmented by giving to a’! and /35" positive values ; or, in other
words, by admitting a sensible parallax. If we consider this pa-
rallax as vanishing, the sum of the squares of the remaining differ-
ences of the eighty-five observations of the star a can be diminished
only to 4:4487 ; that of the ninety-eight observations of the star 4 to
4:7108. If, however, we determine a" and /3'', so that the observa-
tions may be represented as exactly as possible, we can reduce these
sums to 1°4448 and 2°4469, By this means we obtain the mean
error of an observation of the star a= + 0!/"1327, of the star b=
+0"°1605. That the obseryations of the second star are less accu-
rate than those of the first, I consider to be owing to the difference
of the directions of the two stars with respect to the direction of the
double star, The way in which I conceive this difference to affect
the result I shall here leave unexplained; but refer to the complete
discussion, which I shall enter into at some future time, of the pa-
rallax of 61 Cygni.

I have employed the preceding list of the observations of the
distances of the star 61 Cygni from a and b, in two different ways,
in order to deduce from it results for the annual parallax of a
Cygni. have first assumed a" and /3" as independent of each other;
or, in other words, considered it as not improbable that @ and b
themselves may possess sensible parallax. In this way I have
found,

For the Star a.

Mean distance for the beginning of 1838 ......... 4616094 ...... Mean Error.

Annual variation =+4/"3915 —07:0548 ......... +4 3372 ...006 +0/70398

Difference of annual parallax of 6land a... a’/=+0 °3690 ....., +0 “0288
For the Star 8. ,

Mean distance for the beginning of 18388 ......... 706 22909). 70...

Annual variation = — 2/-825+0/-2496 ......... —2 ‘5824 ,..... +0 0434

Difference of annual parallax of 61 and 4...8’= +0 2605 «..... +0 0278

The observations seem also to indicate, that the difference of the
parallaxes of 61 and 6 is smaller than that of 61 and a; which must
be the case, indeed, if itself have a sensible parallax greater than a.
The difference of the computed values of a! and /3'', in fact, exceeds
the limits of the probable uncertainty of the observations ; but it is
to be observed that the probability of equal values of a!! and /3!' is not so
small that we should be inclined to consider the difference of the two
as proved by the observations. Further observations will increase
the weight of both results, and, at the same time, give more accu-
rate values of the annual variations.

I have, therefore, deduced a second result from the observations,
which rests on the supposition that the parallaxes of a and b are in-
sensible ; or that a! and /" are equal. For this purpose, since both
series must now be brought into connexion with one another, it was

Prof. Bessel on the Parallax of the Star 61 Cygni. 71

necessary to deduce the weight of the observations contained in the
second series, the weight of those in the first series being taken as
unit. I have found it =0°6889; and hence the most probable value
of the annual parallax of 61 Cygni =0"-3136. On this hypothesis,
I find the mean distances of both stars for the beginning of 1838, to
be 461'-6171 and 706-2791; and the corrections of the assumed
values of the annual variations, = — 0/0293 and +0!"2395. The
mean error of an observation of the kind of which I have assumed
the weight as unit, is + 0/1354, and the mean error of the annual
parallax of 61 Cygni, = + 0!'-0202.

This hypothesis manifestly represents the observations somewhat
less correctly than the first calculation which was instituted; but
what we lose in this respect is not sufficient to outweigh the
decided preference due to this last calculation. We can form a
judgment upon this point by the following lists of errors of the ob-
servations, which contain their comparisons with two formule;
namely, that of the first calculation and the present hypothesis. I
have also added a third column, which contains the errors that arise
when we assume the parallaxes a!! and (3 in the first formula as
vanishing. This column also shows immediately what differences
were still to be explained by the annual parallax. It shows, in fact,
that these differences are commonly positive or negative, accordingly
as the coefficient of the annual parallax, which the foregoing tables
giye, is positive or negative. [The tables here referred to will also
be found in the Monthly Notices of the Society, as before. }

As the mean error of the annual parallax of €1 Cygni (=0'"3136)
is only + 0"-0202, and consequently not =; of its value computed ;
and as these comparisons show that the progress of the influence of
the parallax, which the observations indicate, follows the theory as
nearly as can be expected considering its smallness, we can no
longer doubt that this paraliax is sensible. Assuming it 03136,
we find the distance of the star 61 Cygni from the sun 657700 mean
distances of the earth from the sun: light employs 10°3 years to
traverse this distance. As the annual proper motion of a Cygni
amounts to 5-123 of a great circle, the relative motion of this star
and the sun must be considerably more than sixteen semidiameters
of the earth’s orbit, and the star must have a constant aberration of
more than 52. When we shall have succeeded in determining the
elements of the motion of both the stars forming the double star,
round their common centre of gravity, we shall be able also to de-
termine the sum of their masses. I have attentively considered the
preceding observations of the relative positions ; but I consider them
as yet very inadequate to afford the elements of the orbit. I con-
sider them sufficient only to show that the annual angular motion is
somewhere about 2 of a degree; and that the distance, at the be-
ginning of this century, had a mininum of about 15". We are enabled
hence to conclude that the time of a revolution is more than 540
years, and that the semi-major axis of the orbit is seen under an
angle of more than 15". If, however, we proceed from these num-
bers, which are merely limits, we find the sum of the masses of both

72 Intelligence and Miscellaneous Articles.

stars less than half the sun’s mass. But this point, which is de-
serving of attention, cannot be established until the observations
shall be sufficient to determine the elements accurately. When long-
continued observations of the places which the double star occupies
amongst the small stars which surround it, shall have led to the
knowledge of its centre of gravity, we shall be enabled to determine
the two masses separately. But we cannot anticipate the time of
these further researches.

I have here troubled you with many particulars; but I trust it is
not necessary to offer any excuse for this, since a correct opinion as
to whether the investigation of the parallax of 61 Cygni has already
led to an approximate result, or must still be carried further before
this can be affirmed of them, can only be formed from the knowledge
of those particulars. Had I merely communicated to you the re-
sult, I could not have expected that you would attribute to it that
certainty which, according to my own judgment, it possesses. I
have the honour to be, esteemed Sir, yours, F. W. Brsset.

XIV. Intelligence and Miscellaneous Articles.

SILICATES OF SODA.
M FRITZSCHE has described two crystallized compounds of
e silicate of soda and water in a memoir read before the Im-
perial Academy of St. Petersburgh.

When silica is dissolved to saturation in a solution of caustic
soda, a liquid is obtained, which is capable of being almost entirely
converted into crystals. If the solution be concentrated, a crystal-
line mass is formed in a few days; whereas if it be moderately di-
luted, it deposits crystalline radiated hemispherical masses, or scales
or lamina composed of crystals which are more or less distinct.
When this compound is prepared on a large scale, crystals are ob-
tained of the size of a pea, which are perfectly formed, and have
polished surfaces; these are the crystals which were submitted to
analysis, and were used for the determination of the crystalline
form ; this salt was analysed in the usual way; that is, it was de-
composed by hydrochloric acid, and the quantities of chloride of
sodium and silica determined ; 66°8 parts of the crystals, pulverized
and pressed between folds of paper to remove their moisture as
much as possible, gave 14:4 of silica and 27°5 of chloride of sodium,
which is equivalent to 14°6 of soda; the quantity of water is then
37°8 or 56°59 per cent. On exposing some entire crystals, but
which probably retained a little moisture, to a strong heat, the loss
amounted to 57°25 per cent. The salt may therefore be considered
as composed of

By analysis. Theory.

RTCA 5:04 Ba SRY, LALO: cdelc; <Jee tug ex Leeder

Soda EGE Bly, OOS: sht. she lo 21°86

Water vvsesas a. OW Drive Nore 78 06°62
100- 100°

The author represents it by Na$ Si? + 27 H.

Intelligence and Miscellaneous Articles. 73

If this salt be exposed to atmospheric air, it is altered by the ab-
sorption of carbonic acid, but it does not deliquesce. Placed under
a receiver over sulphuric acid, it expands, first at the surface, and
after some time even to the centre of the crystal, but it preserves
its form. When heated to 122° Fahr. it fuses and forms a sirupy
liquid, which on cooling does not solidify, but long retains its liquid
state.

The form of these crystals has been ascertained by M. Norden-
skiold; they belong to the prismatic system.

M. Fritzche has succeeded in obtaining another hydrate of the
above silicate of soda, but he has not been able to ascertain the cir-
cumstances requisite for its production ; it was procured in preparing
the foregoing in large quantity; in spherical masses, the surfaces of
which were covered with crystals; the crystals, though of determi-
nate form, could not be measured, but belonged to the system of
axinite ; the properties of the salt were not determined with preci-
sion, owing to the small quantity obtained ; this consisted of

By analysis. Theory.

DliCa ia 6 eet 26° DOM ae ere. 26°94

Soda’ Sete 26°80. 26°53

Water Ns 10 FL APQORH ELS 46°53
100° 100°

The symbol is NaS Si? + 18 H.—L’ Institut, No. 254.

[Representing silica by 16, soda by 32, and water by 9; the first
salt may be regarded as a disilicate of soda with 10 eqs. of water;
and the second as containing 6 eqs. of water.—R. P.]

RESPIRATION OF PLANTS.

M. Colin has read before the Academy of Sciences, a memoir on
the respiration of plants, the experiments detailed in which were
performed with M. Edwards, Sen.

Scarcely any of the phenomena of the respiration of plants have
been hitherto recognised, except the disengagement of carbonic acid
gas; and this has been explained by the combination of the oxygen
of the air with the carbon of the grain. ‘Thus, according to this
theory, the grain is only acted upon by the atmosphere, and the
action of water on the respiration of plants is not considered. In
the respiration of leaves, carbonic acid is evolved during the night,
and during the day it is absorbed, and oxygen is disengaged by the
direct solar rays; and these facts are explained on the supposition
that the carbonic acid absorbed is decomposed by the plant, its
carbon appropriated, and the oxygen disengaged. But this explana-
tion supposes the plant to possess a decomposing power which to
MM. Edwards and Colin it seems difficult to admit; and they have
in consequence resumed the examination of this function of plants.

Hitherto the experiments performed on the respiration of grain
have always been performed in the air ; or when they have been per-
formed in water, the explanations of the phenomena have been

74 Intelligence and Miscellaneous Articles.

limited by what occurs in the air; what has been disengaged in the
fluid has not been examined; but this has been done by MM. Ed-
wards and Colin.

They took a globe with a straight neck, the capacity of which
was from three to four litres of water, (about 183 to 244 cubic
inches,) with which it was filled, and they then introduced forty
large and perfect Windsor beans (feves de marais). 'To the globe
a bent tube was adapted, which was filled with water, and which
terminated in a jar also filled with water. ‘The beans were thus in
contact only with the water and the air which it contained, and
which could not be renewed on account of the mode in which the
experiment was performed; and this is an important circumstance,
and upon which the success of the experiment depends.

The first phenomenon which appeared was the disengagement of
bubbles of air arising from the seeds; at the end of twenty-four
hours the disengagement was considerable. At the expiration of four
days the beans were weighed ; they had increased twenty per cent.
in weight; when put into the ground they came up perfectly, which
proves that they had suffered no change. As to the production of gas,
that which was disengaged after passing through the water, and re-
ceived in the tube and jar, was only a sign of the function; it could
be only that portion which the water did not dissolve, as it was gra-
dually formed ; it was therefore smaller in quantity than that which
was dissolved. The quantity of air which had passed through the
water without being dissolved amounted to from twenty to forty
millimetres (1°22 to 2°44 cubic inches); but that which was dis-
solved in the water, and which was expelled from it by ebullition,
was very considerable. Before the experiment the water in the globe
contained about 4°577 cubic inches of air, and after the experiment
more than 30°5 cubic inches of gas were expelled. ‘Thus the action
of the beans alone produced nearly 30 cubic inches of gas. No doubt,
therefore, can exist as to the action of water in the respiration
of the beans.

It was found that the gas generated consisted of, 1st, an enormous
quantity of carbonic acid; 2nd, an almost infinitely small portion of
oxygen ; and 3rd, a very small quantity of a gas which appeared to be
azote, or at any rate the authors at present so consider it ; its propor-
tion was rather smaller than that of the air contained in the water.

These experiments then prove that during the respiration of
plants water is decomposed, and that the carbonic acid formed is
derived from the oxygen of the water, which unites with the carbon
of the grain. MM. Edwards and Colin propose to examine on a
future occasion whether the carbonic acid thus formed is totally or
partially disengaged, and whether the hydrogen of the water is ab-
sorbed by the grain.—L’ Institut, No. 257.

VALERIANIC ZTHER. BY MM. GROTE AND OTTO.
When valerianic acid or a valerianate is distilled with alcohol and
sulphuric acid, a liquor is obtained which contains a large quantity
of valerianic wether; this «ther separates partly of itself and partly

Intelligence and Miscellaneous Articles. 75

by the addition of water. It has a penetrating odour of fruit and
of valerian; it is colourless; its specific gravity is 0°894; its boiling
point is 272° Fahr. ; it is scarcely soluble in water, but dissolves
very readily in alcohol, ether, and oils. .

The results of the analysis with oxide of copper were

Hydrogen ......+ 10°736 10°851
Carbor Fee jee 64°723 64:963
Oxygen. ......2.5) 24541 24°186
100° 100-
Which indicate the annexed theoretical composition,
28 eqs. hydrogen ...... 174°713 10°628
14 carbon’ 3 )602% 1070:090 65°056
4 Oxygen 6... 400°000 24°321
1644°863 100.
According to these results, this ether is formed of
1 eq. valerianic acid....,.. 10C+18 H+3 0
1 esthem O03, SIN, Ove 4C+10H+10

14C+28H+40
The other properties of this «ther are similar to those already
known.—Journal de Pharmacie, vol. xxiv. p. 365.

ACTION OF SULPHATE OF AMMONIA ON GLASS. BY
M. MARCHAND.

A mixture of hydrochlorate and nitrate of ammonia attacks glass
very strongly, especially when it contains lead ; and the same is the
case with sulphate of ammonia. This salt, as is well known, if
neutral, is converted by the action of heat into an acid salt, giving out
ammonia; it may therefore be considered, under these circumstances,
as an acid salt. If it be heated in a glass vessel, it begins to fuse
at about 284° Fahr.; up to 536° it suffers no alteration, but at this
temperature it gives out ammonia, and sulphuric acid and sulphite
of ammonia sublime, and then it may be observed that the glass is
strongly attacked. All the interior surface becomes dull, because com-
bination takes place between the sulphuric acid and the potash of the
glass, and temporarily, probably, between the ammonia and the sili-
cic acid. Most commonly the vessel, which is frequently acted upon
to the middle of the glass, breaks, and from the fissures there pro-
ceeds a sort of saline fixed white mass, difficultly soluble, and which
is easily found by the blowpipe to be sulphate of potash. M. Mar-
chand states, that he has also frequently observed that watch glasses
containing lead, which he employs to dry substances in vacuo oyer
sulphuric acid, are covered, after a certain time (about two to
four weeks) with numerous cracks, and from which he has easily
detached small fragments. It was impossible, howeyer, to deter-
mine that loss of weight occurred in this case: this phenomenon
could not therefore be derived from a disengagement of inclosed air,

76 Intelligence and Miscellaneous Articles.

as Bischoff, who has made a similar observation, is inclined to sup-
pose; the same appearances have not been observed on the receivers

of the air-pump, nor in any other kind of glass.
Journal de Pharmacie, vol. xxiv. p. 367.

ACONITIC ACID.

M. Buchner, jun. has investigated the properties of this acid, which
was first obtained by M. Peschier of Geneva in 1820, from the
Aconitum napellus and Aconitum paniculatum. M. Reuss, having oc-
casion to prepare a large quantity of the extract of aconite, ob-
tained a considerable portion of a granular dirty white substance,
consisting principally of aconite of lime, and this he sent to M. Buch-
ner, who, in order to separate the aconitic acid from it, first wash-
ed it repeatedly with water and alcohol, to remove the extractive
matter, and then dissolved it in dilute nitric acid. The solution
being filtered, the aconitic acid was precipitated by excess of acetate
of lead. The precipitate obtained, being well washed and separated
by filtration, was diffused through distilled water, and submitted to
a current of hydrosulphuric acid until the aconitate of lead was
completely decomposed. The sulphuret of lead being separated, the
liquor was evaporated with a gentle heat, and the aconitic acid form-
ed a white granular crystalline mass. Some aconites are so rich in
aconite of lime, that nearly as much may be obtained as of pure ex-
tract. In order to dry it sufficiently for analysis, the acid was dried
in a current of air of the temperature of 248° Fahr. By combustion
with oxide of copper the results obtained were,

Hydrogen .....-..--+- 3°44 3°80

OAL fos sso eee 2 41°01 41°84

ORXYPCD ea. - = eeties = 55°55 54°36
100° 100°

The composition of the acid as combined with oxide of silver, ap-
peared to be

Aydrogen ....----e++- 2°23
Warbon.. = 02 cei- conti 48°71
OXYGEN once nis ee =e = 49°06
100°
From which it appears that the free acid is composed of
4 atoms of hydrogen .... -- =r OASOGO be ete
2 Fie ,t p AGALDOM geass revel ocat-\> = 305°744 .... 41°84

4 5p LORY SCH aes = 400°000 .... 54°74

— —_————-

Ct He OS + H?0O = 730°703 100°
while the combined acid consists of

2 atoms ofhydrogen ....-- =| 12°479 .. 2." 2°02

Aes Carn Olt ie a aisvapie <° = 305°744 .... 49°45

3007000 .... 48°53

—_————_

618°223 100°

3S. ,Oxypen

C+ H? O

ll

Intelligence and Miscellaneous Articles. RY

These experiments seem to prove that the acid contained in aco-
nite has the same composition as maleic and fumaric acid; that is
to say, in its free state, like them, the composition is the same as
that of malic acid combined with bases, that it consists of equal
atoms of hydrogen, carbon, and oxygen, and is distinguished from
malic acid in a state of combination by containing an atom less of
water.

The author states the difference between the properties of the
aconitic, maleic, and fumaric acids: aconitic acid does not, like
malic acid, yield regular and distinct crystals; it assumes the state
of a crystalline crust or of mammellated masses, formed of crystals
so small that their form cannot be determined even by the micro-
scope. When pure, aconitic acid is perfectly white, unalterable in
the air, and very soluble in water at all temperatures, it dissolves
also very well in alcohol and in zther.; by evaporation it separates
from its solutions in thick crusts, or in fine ramifications. In this
respect it differs from fumaric acid, which is very slightly soluble,
and from maleic acid, which crystallizes in very distinct prisms. As
to its flavour, the paramalleic acid has a disagreeable nauseous taste,
which aconitic acid does not possess. When exposed to heat these
acids act ina very different manner, and may be readily distinguished;
fumaric acid fuses with difficulty ; when heated to above 392° Fahr.,
it is completely volatilized, and yields asolid sublimate. Maleic acid
fuses at 248°, distils perfectly, and if the heat be raised a little, and
the operation prolonged, it is converted into fumaric acid ; when,
however, it is quickly heated in a retort it is volatilized in a liquid
state, yielding a little fumaric acid, and on cooling, the liquid product
crystallizes.

Aconitic acid acts differently when heated on a sand bath ina
long tube to 266° Fahr. ; it becomes brown, but does not fuse. At
this heat it begins to melt, but it does not boil till heated to 320°
Fahr., and then it becomes red-brown. If it be kept for some time
in this state, it is not converted into fumaric acid, but small colour-
less drops are observed to condense on the surface of the brown
liquid, which on cooling become colourless prismatic crystals; but
the greater part of this acid is converted into a brown tenacious hy-
grometric matter, which dissolves in water and does not crystallize.

Aconitic acid subjected to a sudden heat ina small much-inclined
retort, fuses, becomes brown, yields white vapours which condense
into a bright yellow liquid, of an acrid taste and empyreumatic
smell. Charcoal remains in the retort, but the bright yellow liquid
becomes full of slender prismatic crystals ; when these are separated
more crystallize in the mother water. These crystals are not aco-
nitic acid; when precipitated by acetate of lead they give a floccu-
lent precipitate, which differs from aconitate of lead by its greater
solubility ; the precipitate resembles those obtained with the maleic
and malic acids, in being converted into brilliant crystals by contact
with water, which is not the case with aconitate of lead.

Journal de Pharmacie, vol. xxiy. p. 408.

78 Intelligence and Miscellaneous Articles.

SEPARATION OF COPPER FROM ARSENIC.

According to M. Rose, the separation of these metals is to be
effected by decomposing a solution of them by ammonia, and then
digesting it for a considerable time in an excess of hydrosulphuret
of ammonia, adding to the filtered solution either acetic or muriatic
acid, which precipitates the arsenic in the state of a sulphuret.

M. Buchner having occasion to examine a case of poisoning by
Scheele’s green, resorted to the above method; but soon found that
the sulphuret of arsenic so obtained contained a notable quantity of
copper, notwithstanding the hydrosulphuret of ammonia had been
previously shaken up with a portion of sulphur. The precipitate,
on the addition of acetic acid, was of a dirty flesh-red colour.

M. Buchner after several trials effected the separation in the fol-
lowing manner :—

The metals were perfectly: precipitated from a solution in muti-
atic acid by sulphuretted hydrogen. ‘The precipitate, after being
washed with water holding sulphuretted hydrogen in solution, was
dried and weighed.

A portion of this precipitate was mixed with exactly four times
its weight of carbonate of potash, and eight times its weight of
nitre, and heated in a glass vessel until it melted. The resulting
dark bluish gray mass was, on cooling, boiled for some time in a
quantity of water. Pure oxide of copper remained undissolved,
which was collected and weighed. The arsenic may be separated
from the solution, and the quantity ascertained in the usual manner.
A shorter process however is, after the separation of the oxide of
copper, to supersaturate the solution by muriatic acid, and ascertain
the quantity of sulphur or sulphuric acid by means of barytes. ‘The
quantity of sulphur added to the metallic copper, and that deducted
from the weight of the combined sulphurets, gives the quantity of
the sulphuret of arsenic, from which the weight of the arsenic may
be caleulated.—Annalen der Physik und Chemie. J. C. Poggendorff,
vol. xliv. p. 137, 1838.

ON A METHOD OF DISTINGUISHING STRONTIAN FROM BARYTES
AND LIME. BY HENRY ROSE.

The qualitative examination for strontian is so far difficult as all
the substances which precipitate solutions of strontian, also more or
less precipitate solutions of barytes and lime. In all cases with respect
to reagents, strontian stands between barytes and lime. Some re-
agents, viz. sulphuric acid, solution of chromate of potash, benzoate
of ammonia, iodate of soda, precipitate barytes perfectly from its solu-
tion; strontian less perfectly, and lime still less so; other reagents,
as the alkaline oxalates, on the contrary, precipitate lime perfectly,
strontian imperfectly, and barytes still more imperfectly. Some
reagents which do not precipitate strontian or lime perfectly, pre-
cipitate barytes, viz. hydrofluosilicie acid; and there are others
which can with certainty distinguish solutions of barytes or stron-
tian from solutions of lime ; as, for instance, solution of sulphate of

Meteorological Observations. 79

lime. But there is no known reagent which acts similarly towards
solution of barytes and lime, and differently towards solutions of
strontian. Ferrocyanate of potash is, however, such a reagent ;
this occasions precipitates in neutral solutions of barytes and lime,
provided they are not too dilute; they are, according to Mosander
and Duflos, combinations of ferrocyanate of potash and barytes, and
of ferrocyanate of potash and lime. Even in diluted solutions of
barytes this compound after some time crystallizes on the sides of
the glass in very distinct crystals. Bunsen has described them in
Poggendorff’s Ann. vol. xxxvi. Strontian is not precipitated from so-
lutions even when concentrated, nor are any crystals formed after
resting for a long time. It appears, therefore, that ferrocyanate of
potash in combination with strontian forms a soluble salt. By this
means a neutral solution of strontian may be distinguished from one
of barytes, and from lime, and also from magnesia, as the latter like-
wise gives a precipitate with ferrocyanate of potash.—Poggendorff’s
Annalen. 1838. No.7. p. 445.

Bririsn Association FoR THE ADVANCEMENT OF Sciencr: Instru-
MENTS FOR THE ALLEVIATION OF DEAFNESS,

We are requested to intimate, that a Committee having been ap-
pointed at the Newcastle meeting of the British Association, held in
the month of August last, for the purpose of considering and re-
porting on the instruments which may be deemed best adapted for
assisting the hearing in cases of deafness, the Committee will be
happy in being favoured with the co-operation of such persons as
may be disposed to assist their inquiries, either by suggestions, or
by the loan of instruments or apparatus in explanation of their views.

Letters or parcels are requested to be transmitted, postage or
carriage paid, to the care of Messrs. 'T'aylor, Red Lion Court, Fleet
Street, Printers to the Association.

METEOROLOGICAL OBSERVATIONS FOR NOVEMBER 1838.

Chiswick.—Nov.1. Overcast: rain: clear at night. 2,3. Fine. 4, Rain.
5. Fine, 6. Very fine. 7. Rain: fine: windy at night. 8. Clear and fine :
rain. 9. Heavy rain. 10. Clearand fine. 11. Dense fog: 12, Clear and
cold. 13, Frosty: fine. 14, Frosty and foggy. 15, 16. Foggy. 17. Fogey:
fine. 18,19. Rain. 20. Cold haze. 21—93, Foggy. 24. Bleak and cold. 25,
26. Frosty. 27. Overcast. 28. Heavy rain: hurricane at night. 29. Boister-
ous with heavy rain: much thunder and lightning at night. 30. Rain. fine.

Boston.— Nov. 1. Fine: rain early asm. 2, 3. Fine: rainr.m. 4. Cloudy :
rain. 5. Cloudy. 6. Fine. 7. Cloudy: rain early a.m. 8 Fine. 9, 10.
Cloudy. 11. Foggy. 12,13. Fine. 14. Foggy. 15. Cloudy. 16, 17. Foggy.
18, Cloudy: rain a.m. and vm. 19. Stormy. 20, 21. Cloudy. 22. Cloudy:
rainearly a.m. 23, 24. Cloudy. 25, 26. Fine. 27. Stormy. 28, Cloudy :
Stormy with rain p.m, 29, Stormy: rain early a.m. 30. Stormy.

Applegarth Manse, Dum/fries-shire.—Nov. 1. Heavy showers: hail. 9. Fair
but cloudy. 3. Frequent showers, 4, Fair andcloudy. 5. Moist: slight
showers. 6, Fair: one slight shower. 7. Rain all day: high flood. 8. Occa-
sional showers. 9. Fine day. 10. Fine day: rainy.m., 11. Fine day after
snow. 12. Hard frost: clearand serene. 13, Temperate. 14. Cloudy and
Taw, 15. Thick fog. 16, Cleared up: dry. 17. Rain in the night: cold.
18, Cold drying day : snow on hills. 19, Cold and threatening a fall. 20.
Still cold, yet dry. “21. Still threatening a fall. 22—96. Cold and dry, 27.
Cold: snow three inchesdeep. 28. Wet in the night; dittorm. 29 Very
wet day and stormy. 0, Showery and stormy; flood,

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et

THE
LONDON ann EDINBURGH
PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.)

FEBRUARY 1839.

XV. Comparison of the Magnetic Lines of no dip and of least
intensity. By Masor Sasine, F.R.S.

[With a Map, Plate 1V.]

To Richard Taylor, Esq.
Dear Sir,

i my report on the magnetic intensity of the earth, pub-
lished in the last volume of the Reports of the British As-
sociation, it is remarked, that “* every geographical meridian
has a point of minimum (magnetic) intensity; if these points in
different meridians were connected by a line, that line would
separate the intensities of the northern from those of the
southern magnetic hemisphere. It would be in some respects
analogous to the line of no dip; but it would not be a line of
equal intensity, as it would consist of intensities varying from
unity to the lowest on the globe. Such a line traced on the
map is found to differ very considerably in geographical po-
_ sition from the line of no dip.”

It may be interesting to those of your readers who are
magneticians to compare the positions _of these two lines;
namely, that of no dip, and that of least intensity. They are
drawn on the accompanying map, which is divided into two
portions, to prevent its being inconveniently long for the oc-
tavo size, one portion ponies 205 degrees, and the other |
the remaining 160 degrees. ‘The lines of equal intensity —

isodynamics) of 1°0, 0°9, and 0°8 are drawn in faint
ot lines, and are taken from the general map in the Re-
port referred to. The line of least intensity, now drawn for
Phil. Mag. S, 3. Vol. 14. No. 86. Feb. 1839, G

A O we —— oo

82 Mr. F. Watkins on the Evolution

the first time, is characterized by a strong unbroken line.
It has obviously two points of minima, and two of maxima;
those of minima being nearly in the middle of the two divi-
sions of the map, one in each, and the points of maxima co-
inciding nearly with the meridians which separate the divi-
sions.. The line of no dip is marked by the broken line. It
is taken from Captain Duperrey’s map, and rests principally
upon observations made by that distinguished officer in the
voyage of circumnavigation of the Coquille, undertaken by
order of the French Government for that express object.
His observations were at stations in the immediate vicinity
of the line of no dip, and occasionally on the line itself. In
assigning its position from the former class of observations Cap-
tain Duperrey has employed the well-known formula of M.
Biot’s hypothesis and has computed by it the geographical
distance’ to be allowed for the small observed values of the
dip. The facts of observation are thereby in some degree
mixed up in their representation with theoretical assump-
tions; but the distances of the places of observation from the
line to be determined by them are usually so small, that any
error which the theory may have induced must be insensible
on the scale on which the present map is drawn.

The epochs to which the lines of dip and intensity respect-
ively correspond are very nearly the same: that of the line
of no dip is 1825, and the line of least intensity rests on ob-
servations of which the greater part were made between 1817
and 1836.

It will be seen that these lines, which until lately were
considered to be identical, and which by many are still sup-
posed to be so, with at most merely local interruptions, are
systematically distinct, and in one quarter of the globe in par-
ticular are separated by a space equivalent to 20 degrees of
latitude, or 1200 geographical miles.

I remain, dear Sir, yours, &c., -
Tortington, Jan. 1, 1839, Epwarp SaBiNe.

XVI. On the Evolution of Heat by Thermo-Electricity. By
Mr. ¥. Warxins.
To the Editors of the Philosophical Magazine and Journal.
GENTLEMEN,

(THE excitement of electricity by the influence of tempera-
ture is evident by the production of the spark, and of the
chemical, physiological, magnetical and mechanical effects or-

a

of Heat by Thermo-Electricity. 83

dinarily attributed to that agent; but I believe it has never
yet been recorded that the phenomena of heat, as evolved by
the metal employed in its transmission, have been observed as
a result of this mode of excitation.

I have lately observed this fact with a delicate air
electro-thermometer of the construction suggested by my
friend Mr. W.S. Harris, and also with a Bréguet’s metalline
thermometer, arranged with M. De la Rive’s contrivance for
passing a current through its helix.

The indications afforded by both instruments were very
distinct and satisfactory, and could not be ascribed to any
direct conduction of heat, for I placed ice around the wires,
which completed the circuit between the battery and the
indicating instruments.

I employed a massive thermo-electric battery, consisting
of 18 pairs of bismuth and antimony prismatic rods, four
inches long, united consecutively, similar to the arrangement
of M. Van der Voort, of Amsterdam.

When the electricity was excited by applying a hot iron
heater near one extremity of the battery and ice at the op-
posite extremity, with the circuit complete through the air
electro-thermometer, the heating effect on the fine platinum
wire in the spherical air reservoir was immediately visible by
the ascent of the coloured liquid up the fine glass tube com-
municating with it. The elevation of the liquid column was
about 20°, which occupied a space on the scale of one inch.

When the Bréguet’s thermometer was placed in the circuit,
the index attached to the bottom of the compound metallic
helix moved round 10° in the direction of the coils, the helix
expanding by the elevation of temperature conferred by the
passage of the thermo-electric current.

The elevation of temperature of the metals forming the
electric circuit in both instruments, was always manifested
when the circuit was completed, and remained constant, but
on breaking the circuit the loss of heat was very apparent ;
therefore I have no reason to doubt that the heating effects
so conspicuously shown, were due solely to the transmission of
the thermo-electric current.

I have repeated the experiments many times with uniform
success; and if you consider the fact of sufficient importance
to be announced in your Magazine, this brief notice is at your
disposal for that purpose.

I remain, Gentlemen,
Yours, &c.
5, Charing Cross, 24th Dec, 1838. Francis WATKINS.

G2

[ 84 ]
XVII. Preliminary Notice of some Experiments on the Action

of Acetone on the Bichloride of Platinum (Platin Chlorid.).
By Wiu.taM C. ZEIse of Copenhagen *.

W HEN a solution of bichloride of platinum in about 2}

parts of acetone is distilled to the consistence of syrup,
and the product once or twice redistilled, a mixture of several
new combinations of the protochloride (chloriir) which is
thereby formed is obtained. The rectified fluid contains a
considerable quantity of muriatic acid, and at least one zthe-
rial substance. It is very difficult to obtain these different
combinations separate, and though I have spent already con-
siderable time in the attempt, I am not even yet certain that
I have obtained them all in a state of purity. One of these
compounds, a yellow crystallizable substance, the compo-
sition of which may be thus represented,

Rise? Clee GCs alone ee os

appears to deserve a particular description. To obtain this
substance, the brown, tarry, acid residue is agitated with
fresh portions of water so long as this acquires a brownish
yellow colour, and the solution quickly filtered through linen
to separate the undissolved resin or pitch-like matter. The
lower part of the solution soon becomes turbid, and in the
course of half an hour or an hour a tolerably large quantity
of small yellow crystals precipitates. The mother liquor,
when separated from the crystals, is placed, zm vacuo, over
sulphuric acid with hydrate of potassa or lime until it has
evaporated to a brown crystalline mass: this mass is then to
be treated with water in the same way as before, by which a
new portion of the crystalline body will be obtained ; but this
is almost always of a dark brown colour. To obtain it pure
it must be dissolved in the acid fluid obtained by distilling the
solution of the bichloride in acetone, and the solution so
made distilled to the consistence of syrup, and then treated
with water in the manner before described. Finally, in order
to remove all remaining traces of the brown colouring matter,
the crystallized product, after being well pressed and dried
between the folds of bibulous paper, is to be dissolved in ace-
tone, the saturated hot solution filtered into a wide-mouthed
glass vessel, and, when cooled, and the crystals which have
been deposited separated, it must be evaporated by careful
distillation to that point, when on cooling the greatest part of
the substance is deposited. ‘The crystals thus obtained are
to be washed in a small quantity of acetone, and then dried.

j
:
|

* Translated and communicated by E. Solly, Jun.

On the Action of Acetone on Bichloride of Platinum. 85

I have likewise obtained a considerable quantity of this sub-
stance by keeping, for 24 hours, a mixture of acetone with
the bichloride in a well-closed vessel. I call this substance
Metacechlorplatin.

Metacechlorplatin is of a sulphur yellow colour; the cry-
stals are small and difficult to measure. It is very nearly
without any smell. After having been dried in the air, it
loses nothing in weight when placed in a vacuum over sul-
phuric acid, whether at common temperatures or raised above
100°. It inflames very easily, and burns with a partially
green flame, leaving a silvery white residue of platinum.
Heated in a retort it blackens, and without swelling up it
gives out abundance of vapours, which are at first peculiar,
but afterwards smell strongly of muriatic acid; a part, at
least, of these vapours easily condenses into an oily substance.
The carbonaceous residue burns slowly in the open air, like
tinder, and leaves a residue of silvery white platinum. At
common temperatures it is almost wholly insoluble in water ;
when heated in it, it forms a yellow solution, which, however,
contains only a very little of the salt. When boiled, this
solution threw down a brown flocculent substance, whilst
that portion which was not soluble was changed into a brown,
slimy mass without any visible appearances of metallic plati-
num. It seems to be quite insoluble in ether. At common
temperatures alcohol acts but little upon it, but when heated
it dissolves a portion, acquiring at the same time a yellow
colour, on cooling a yellow crystalline powder is deposited.
Muriatic acid, even the most concentrated, dissolves it only
at higher temperatures; the acid solution may be raised to
the boiling point without visible change. A solution of caustic
potassa easily dissolves metacechlorplatin, forming a brown
solution. Solutions of chloride of potassium or sodium, when
heated, also dissolved it, and the yellow solution underwent no
change on boiling. The determination of the quantities of
carbon and hydrogen in metacechlorplatin was made by burn-
ing one portion with oxide of copper, and another portion with
chromate of lead. Its composition(P]. Cl? + C® H'° O) shows
by comparing it with that of acetone, (C° H'* 0%), that in it one
atom of the protochloride of platinum replaces H? O. As how-
ever there appears to be formed at the same time several other
combinations of chlorine, the action is probably not so simple.
Certainly it is probable that a combination takes place of
2 atoms of chlorine with 2 atoms of hydrogen as in the action
of bichloride of platinum on alcohol, and in this case there is
formed likewise through the action of 1 atom of oxygen, one
of the compounds resembling aldehyde (see my paper on the

86 On the Action of Acetone on Bichloride of Platinum.

inflammable chloride of platinum in Poggendorff’s Annalen,
vol. x]. p. 251.). It also appears worthy of notice that, whilst
by the action of bichloride of platinum on alcohol, 2 atoms
of the protochloride combine with 1 atom of ztherin (C* H'),
here only i atom of the protochloride, but in addition to this
also H®. O. (which perhaps replaces the second atom of the
chloride) forms a combination with C®, H®.

After obtaining the last brown crystallized portions of meta-
cechlorplatin by evaporation zn vacuo, there remained still a
brown sour fluid; if this were heated in a retort it became
turbid and entered into tolerably strong effervescence, during
which an etherial fluid passed over; and in the course of from
half an hour to one hour, large quantities of flocculi of a coal-
black colour had separated from the fluid, which had then be-
come colourless. I will here only remark of this body, that
when slightly heated, it burns with explosion; for the present
I shall it pueracechlorplatin.

When water can dissolve no more of the original syrupy
product of the distilled solution of the bichloride, there re-
mains a considerable quantity of a brownish black pitch-like
substance—for convenience sake I call this platinharz*. At
common temperatures it is brittle like resin, and breaks with
a vitreous fracture; and when it is very carefully digested in
water and then dried in a vacuum over sulphuric acid and
hydrated potassa, it is very easily pulverizable. When
slightly warmed it becomes soft, and may then be kneaded
like wax and drawn out in threads. Inflamed it burns with a
very brilliant and somewhat greenish flame, leaving metallic
platinum. Heated in a retort it swells up considerably, giving
off at the same time abundant fumes, of which a portion easily
condenses; the carbonaceous residue burns in the air very
slowly and leaves metallic platinum. Caustic potash dissolves
the resin entirely ; acetone almost the whole, and alcohol and
zether the greater part of it. That portion which was insolu-
ble in the two last-mentioned fluids dissolves in acetone, from
which a brownish black body (soluble only in acetone and a
solution of caustic potassa) was separated by ether: for the pre-
sent I shall call this substance chlorseplatin. ‘That portion
which is soluble in alcohol and ether appears however still to
contain two distinct bodies. This, like the metacechlorplatin,
as well as the other primary and secondary products, I hope
soon to be able to describe more fully. In connexion with
this, I am at present also occupied with investigating the
action of metaceton, pyroligneous spirit, and oil of turpen-

* Platinum Resin, E. Solly.

ee ee Pa

On certain Mineral Substances of Organic Origin. 87

tine upon the bichloride of platinum. I also intend to exa-
mine some other metallic chlorides and haloid bodies under
the same circumstances.

XVITi. On the Composition of certain Mineral Substances of
Organic Origin. Nos. VI. VII. VIII. Mineral Resins.
By James F. W. Jounston, M.A., F.R.SS. L. & E., F.G.S.5
Sc. §c., Prof. Chem. and Min., University, Durham.*

No. VI. Highgate Resin or Fossil Copal.

HIS substance derives its names from the locality in

which it was first found in any quantity, the blue clay
of Highgate Hill near London, and from its similarity to co-
pal resin in hardness, colour, lustre, transparency, and diffi-
cult solubility in alcohol}. For the two fragments which
have afforded me the following results I am indebted to the
liberality of my friend Mr. Brooke.

1. The first fragment analysed was translucent, of a dirty
gray colour, and when broken emitting a resinous odour.
In the air it volatilized by a gentle heat, leaving a small resi-
due of charcoal and earthy matter. ‘The former being burned
away, the latter weighed 0°136 per cent.

9:905 grs. burned with oxide of copper gave 10°508 ers.
of water and 30°795 of carbonic acid. ‘This is equal to

Carbon......... = 85°408
Hydrogen...... = 11°787
Oxygen ...... = 2°669

ASRES: 5.0 k-nsn- 0°136—100-000.

2. The second fragment was clear, pale yellow, and semi-
transparent. It was covered with a thin coating of a browner
apparently altered variety, of which, from the smallness of the
quantity at my disposal, I was not able wholly to divest it.

5°509 ers. gave 5°69 grs. of water and 17:07 of carbonic
acid. ‘This is equal to

CarOliesecscccscss ==. SO'ATT
Hydrogen........ = 11°476
Oxygen seeccome = 2°847—100°000.

Assuming the latter specimen to be the purer, this sub-
stance is represented by the formula C4, H,, O,, since

Calculated. Found.

40 Carbon = 3057'480 85968 85°677
32 Hydrogen = 399°347 11°228 11°476
1 Oxygen = _ 100:000 2°804 2°847
3556°827 100°000 100:000

* Communicated by the Author.
+ For a description of this substance see Phillips’s Mineralogy.

88 Prof. Johnston on the Composition of certain

The small defect of carbon and excess of hydrogen in the
analysis are both on the side in which they ought to appear
when experimental results are compared with an accurate
formula.

This resin therefore presents another example of the con-
nexion of resinous substances with oil of turpentine Cy) Hy);
and if the rational formula C,, H,,+ 0 be the true one, it ex-
hibits the lowest state of oxidation of this radical with which we
are yet acquainted. It is very slightly acted on by alcohol,
but the solution gives a white precipitate with an alcoholic
solution of acetate of lead. It is either altogether an acid
resin therefore, or it contains a small quantity of a more solu-
ble resin which is so.

VII. Resin from Settling Stones.

In Brewster’s Edinburgh Journal of Science, N.S., vol. iv.
p. 122, I described as a new variety of mineral resin, a sub-
stance I had met with among the old heaps of a lead-mine
in Northumberland known by the name of Settling Stones,
the working of which has been recently resumed. ‘This mine
is situated at the point of junction of a number of intersecting
faults and veins, along which the strata are thrown up and
down in various directions. By one of these faults the great
whin sill of that district is brought to day, and forms an
escarpment over which the waters of a little rivulet descend
from a height of 20 or 30 feet. Near the veins the trap is
much impregnated with lime, and the cheeks or walls of
the vein are sometimes almost a perfect limestone, and have a
gray or bluish gray colour. It is on these walls of the vein,
resting on and occasionally covered by cale spar, brown spar,
or pearl spar, that the resinous substance occurs. It is in the
form of drops or flattened portions, more or less rounded, as
if it had once been in a fluid or softened state. It is hard,
brittle under the hammer, but exceedingly difficult to reduce
to fine powder in the mortar: even after long rubbing the
angular fragments can still be recognised. Its colour varies
from pale yellow to deep red, its specific gravity from 1:16
to 1°54, and it exhibits a pale green opalescence. It does
not melt at 400° Fahr., but it burns in the flame of a candle,
and gives empyreumatic products when fused in a close tube
over a spirit-lamp. It is insoluble in water and is very slightly
acted upon by alcohol.

Having a small quantity of this resinous substance at my
disposal I availed myself of the opportunity of determining
its composition, with the view of comparing it with that of
the fossil copal above analysed. In external appearance they

Minerals of Organic Origin.— Mineral Resins. 89

possess some resemblance, but their origin must be considered
as entirely different. The one occurs in a vast deposit of
tertiary clay, the other in a mountain limestone district, and
in the centre of an enormous intruding mass of stratiform
basalt. ;

5°83 gers. gave 5°695 of water and 17:95 of carbonic acid:
1°29 ers. left on burning in the air 0:042 of brown ash =
3256 percent. These are equal to

Carbon...... 85'133 or 40 atoms.
Hydrogen... 10°853 or 31:2 atoms.
Ashes ...... 3°256—99°Y42.

It is therefore doubtful whether this resinoid substance
really contains any oxygen or not. It may be only an im-
* pure carbohydrogen = C, H,, agreeing in composition with
the hypothetical acetyle, or it may, like petroline, contain the
elements in the proportions in which they exist in oil of tur-
pentine C,, H,,. I regret that my supply of the substance
did not permit me to repeat the analysis; and though I have
revisited the mine in the hopes of obtaining a fresh supply, I
have not been fortunate enough to meet with a single speci-
men.
VIII. Berengelite.

The specimens of the substance for which I propose the
name of Berengelite were given to me by my friend Mr. Fryer,
of Whitley House, near North Shields, and were obtained by
him during his residence in South America. Of the circum-
stances under which it occurs Mr, Fryer thus writes to me:

** Of the resin or asphaltum from South America, I can
unfortunately give you but a very imperfect account. I one
day found in the yard of the Custom House at Arica a large
convoy of llamas loaded with it, and all the information I
could obtain from the men having charge of it was that they
brought it from the province of St. Juan de Berengela, about
100 miles from Arica, that it was found in very large quan-
tities, and formed, according to their description, something
like a lake resembling the pitch lake of Trinidad. It is ex-
tensively used for paying boats and vessels at Arica, and, I
believe, on the whole coast of Peru.”

This substance is hard, brittle, may be scratched by the
nail, has a resinous fracture and lustre, is of a dark-brown
colour with a tinge of green, but gives a yellow powder. The
external appearance of the masses as they were brought
home appears to indicate that the whole had formerly been
in a softer state so as to yield easily to compression. It is in-
soluble in water, but dissolves readily and in large quantity in

90 Prof. Johnston on the Composition of certain

cold alcohol or zether, giving brown solutions. A small re-
sidue of earthy impurities is left. By evaporating the alco-
holic solution, the resin is obtained of greater transparency,
transmitting light of a bright red colour, fusing easily on the
water-bath, and remaining soft and unctuous at the ordinary
temperature of the atmosphere. It gradually recovers its
brittleness, but after the lapse of three or four months it is
still soft, and adheres in some measure to the fingers. This
property appears to be possessed by many other resinous
substances and explains the semifused appearance of the im-
ported masses.

It has a peculiar, unpleasant, resinous odour. After fusion
for some time at 212° Fahr., the unpleasant odour disappears,
and is succeeded by an agreeable fragrance. On cooling again,
it resumes after some time its original smell. When chewed
in the mouth it imparts a slight sensation of bitterness; but
the alcoholic solution has a disagreeable very bitter taste.

Like most other resins it is nearly insoluble in a concen-
trated solution of caustic potash. Boiled in more dilute al-
kali it gives a yellow solution, from which the resin is again
precipitated by acids. The alcoholic solution gives with a si-
milar solution of acetate of lead a copious yellow precipitate.
It is therefore an acid resin. Its alcoholic solution is rendered
milky by liquid ammonia and passes milky through the filter.

Burned with oxide of copper

12°732 grs. gave 33°37 of carbonic acid and 10°54 of water.
12:40 grs. gave 32°44 of carbonic acid and 10°445 of water.

These are equivalent to
1 2

Chalsovurneag i! 7ok72 72°338
Hydrogen....... 9:198 9°359
Oxygen sseecseeeeee 18°330 18°303

100°000 100°000

These results agree very nearly with the formula Cy) Hs, Og,
which gives

40 Carbon... = 3057°480 = 72°036
31 Hydrogen = 386°8676 = 9°115
8 Oxygen... = 800000 = 18°849

4.244°3476 100°000

and represents a constitution analogous to that of colophony
and some other resins of which oil of turpentine is the radical.
But as the quantity of carbon indicated by this formula is
less than that found by analysis, we ought probably to prefer
one or other of the two formulz

Minerals of Organic Origin.— Mineral Resins. 91

Carbon 727533 Carbon 72°322
C,, Hs; Os =| Hydrogen 8:929 or C,, Hy, Os = | fisdrogen 9-215
Oxygen 18°538 Oxygen 18:463

100-000 100-000
I am inclined, therefore, in the mean time to prefer the
former of these two C,, H;, O,, though the discovery of any
mixture or impurity in the resin may hereafter show either of
the others to be a more correct representation of its elementary
constitution. The establishment of the first, C4. H3, O,, from
its analogy with the formula for colophony, would appear from
theory the most likely, were there not other resins, the analyses
of which I have already published, which appear to deviate
from the general formula

C,H fe a+y

by which many of the resins may be represented. To this
subject I shall return in a future paper.

Origin of the Mineral Resins.

As I am not in possession of any other mineral substance
of organic origin exhibiting the characters of a resin, it may
not be improper here to advert to the probable origin of this
class of substances.

1, Fossil Copal.—The composition of this substance clearly
indicates a vegetable origin. It has been found in small
quantities disseminated through the London clay. Under
what circumstances could this vast deposit of clay be formed ?
Most probably along the course, or in the estuary of some great
river, or in the bottom of a lake into which its waters were
poured. And if at this period the climate were warmer in these
latitudes than it now is, a circumstance in regard to which
geologists seem agreed, we should expect to find (recent) resins
similar to the fossil copal in similar localities, if any now exist
and under a similar sun. From what we know of the Guianas
stretching between the river Orinoco on the north and that
of the Amazons on the south, a country abounding in rivers
and lakes, liable to heavy rains and floods with a climate hot
and moist, we should suppose it to be not very unlike that
which poured its muddy rivers into the London basin, and
buried beneath its waters occasional fragments of its trees, its
resins, and its other vegetable productions.

From the island of Cayenne on this coast, and probably
from the interior of French Guiana, is imported a resin the
produce of the locust tree, which like the Highgate resin has
much resemblance to copal, and is known in commerce by
the name of animé resin. ‘This resin has been analysed by

92 Prof, Johnston on the Composition of certain

Laurent, and found by him to have a composition approach-
ing very nearly to that above given for the fossil copal. The
comparative results are as follows:

Animé Resin. r)

we

Fossil Copal.
VE

Carbon ...... S4°6 85*408 85°677
Hydrogen ... 11°5 11°787 11°476
Oxygen .. 3°9 2'669 2847
100°0 99°864 | 100°
From the above result he deduces for animé resin the
formula C,, H,3; O, which gives per cent,
Carbon. ..0+.000. 85°66
Hydrogen ...... 11°538
OXyZeN eererseee 2°802

100°
The numbers given by this formula differ from those ob-

tained by Laurent in the oxygen and carbon to the amount of °

one per cent., while they are almost identical with those given
by the analysis of the fossil copal. As the hydrogen however
is always in excess, the formula Cy) H3. O above deduced from
my analysis is to be preferred.

Without, however, dwelling upon this discrepancy, it is in-
teresting to find a resin still growing nearly if not absolutely
identical in constitution with one produced and buried at a
period so remote; and while this fact establishes the vegetable
origin of the fossil copal, it may be considered as throwing
some additional light on the nature of the climate at that re-
mote epoch and as confirming the evidence of other facts in
regard to the temperature of these latitudes during the depo-
sition of the London clay.

2. Resin of Retinasphalt * = Cy, Hy, Oz.

The origin of this substance, found in the tertiary formation
of Bovey in Devonshire, of nearly the same age as the Lon-
don clay, is clearly indicated by the mode in which it occurs,
It is scattered throughout the deposits of lignite, and is pene-
trated by twigs and hollow quadrangular spines, apparently
the leaves of a coniferous tree. ‘That it is the resin of some
such trees is therefore very probable; that it has flowed in a
liquid state is also probable from its being mixed with so
much clay, and it is not unlikely that it may have undergone
some change of composition since it was first deposited. We
know as yet however too little in regard to the composition

* See Lond. and Edinb. Phil. Mag., vol. xii. p. 560.

i i

Minerals of Organic Origin.— Mineral Resins. 93

of the resins which exude from the pines of warm climates to
justify us in attaching much weight to this last conjecture that it
has undergone a change since it was deposited. Colophony
is C,, H,; O, so that this resin might be formed by substituting
an atom of carbonic acid for one of hydrogen, since

Cy H,;O0 - H+ CO, = Ca, Hy, Os

3. Middletonite * = C.) Hy, O.

- From the circumstances under which this substance occurs
in the coal of Yorkshire and Staffordshire in thin layers and
masses in the body of the coal, I have already stated that it is
to be regarded as the altered resin of the trees of the epoch of
the great coal formation. That it has undergone a change is
evident not merely from its properties, but from the apparent
impossibility that a resinous substance should remain unal-
tered while the wood which enveloped it was converted into
coal. Mr. Embleton, the intelligent viewer of the Middleton
coal mines, considers the opinion of its being a changed resin
to be confirmed by the appearance of the coal with which
it is in contact, which appears to him to bear a close resem-
blance to a changed bark.

The pseudo resin of Settling stones is probably no further
of yegetable origin than that it may have been distilled or
volatilized out of vegetable matters scattered throughout the
dark shale and other rocks with which the trap, near which it
is found, had come into contact while in a fluid state,

Guyaquillitey = Cy Hog O¢
Berengelite = Cy, Hs, Os

With the geological position of these two substances I am
wholly unacquainted. The one is said to form large deposits
in the neighbourhood of Guyaquil, the other to occur at least
15 degrees further south, forming a species of lake. ‘The
proximity of the volcanic chain to both localities, the former
being almost at the foot of Chimborazo, renders it not un-
likely that they may be, or may have been, distilled from ve-
getable deposits lying beneath; and though true resins have
seldom been met with except in substances of known vegetable
origin, yet since the petroline of Boussingault contains carbon
and hydrogen in the same proportions as in oil of turpentine,
there is no difficulty in conceiving that under favourable cir-
cumstances this and other compounds of similar constitution,
existing in deposits of petroleum, may undergo oxidation and
produce resins similar to those actually found as mineral
productions in South America. Before we can obtain clear
ideas on the subject however, we must obtain more exact in-

4. and 5.

* See L, and E, Phil. Mag., vol. xii. p. 261. | See vol. xiii, p. 329.

94 Prof. Johnston on the Composition of Resins.

formation regarding the circumstances under which they ac-
tually occur. ;

The past6 varnish described by Boussingault* is closely
allied in constitution to the berengelite. This substance when
freed by digestion in alcohol from a little green resin with which
it is mixed, is colourless and possesses many of the properties
of caoutchouc. It is very tenacious, and stretches into thin
membranes, which are applied as a varnish to wooden vessels.
It adheres strongly and after a time hardens, but never cracks.
It forms a soap with caustic potash, from which acetic acid
separates it. When dried and heated to 130° Cent. = 266°
Fahr., the varnish thus separated melts, and on cooling is
brown, tenacious, and (ow) soluble in all proportions in
alcohol, zther, and oil of turpentine. It does not appear from
Boussingault’s paper whether the previous solution in caustic
potash be necessary to the production of this change, though
he does speak of a remarkable modification being caused
by caustic potash. The composition of the pure varnish (A)
and of the sesin or modified varnish (B) are thus given, the
first being a mean of three, the second of two analyses.

A. B. Calculated.
Carbon ==107 1°76 71°25 71°825
Hydrogen = 97633 10°30 9°381
Oxygen = 18°600 18-45 18°794

—

—_— —_

99°999 100°000} 100:000

The third column is calculated according to the formula
%49 H32 Og, which agrees very well with the analyses of the
varnish. It is not improbable however that the reszm should
be represented by a formula somewhat different.

The pastO varnish is brought to the neighbourhood of
Quito from the high land of Macao, on the eastern slope of
the Andes, from which the waters descend to the river of the
Amazons. Except that it is of vegetable origin nothing
is known regarding it, the tribes of Indians from whom it is
obtained being still independent. ‘The difference of its pro-
perties previously to fusion forbid the supposition that it is
identical with the berengelite; were a distance of 20 degrees
of latitude between the places from which they are respect-
ively brought, not sufficient to render a common origin highly
improbable.

It may not be uninteresting to present here a comparative
view of the formule by which the several resins of which ana-
lyses have hitherto been published may be represented.

* An. de Chim. et de Physique, vol. lvi. p. 216.

eo a ee ee ee ee

eet 25

Col. Wright’s Meteorological Observations in Colombia. 95

Resin from the root of

Arbrea Brdi sesereeveee = C3, Hz, O Dumas.
ANIME FeSiIN .sececeeeeeeeee = Cio H3z, O Laurent.
Bossil copal sayse.cdedessseuen = Cy, Hg, O
FEMI Tesi... .cceesessedsases’ = ‘Cy’ Hy5:0,.; Rose.
Colophony (pinic and syl- Y _ C. H..o, § Liebig and

VIC ACIC) ceccscecececeee § 49 ~~ 80 4 ') Trommsdorf.
PastO varnish sese.seeeeeeee = Cyy Hy O3 Boussingault.
B ; = Og Hs) Of Por

EPP CUES con anetesagazss Co

j j =I 4h SAS Pe
Middletonite) .i5.0; eereeess: =) Cy Hog O;

Guyaquillite .....ses0c000. == Cy Hy Og
Resin of retinasphalt == Ci Hg 'Qz ?..08
(retinic acid) ......00 =4C,, Hg, O;
==! Cy e 538.08
G a Secret eestseseeceee 40 24 8
aces = Cyg Hag Ojo a
= Cy Hoy Og? | Apjohn and

Eblanin seesnsssannseneee), C,, Hi, O; f Gregory.

In these formulze, which from the nature of the substances
may all be subject to future corrections, we see a mode of re-
presenting, at least approximately, all the analysed resins
(with one exception) by quantities in which that of carbon is
constant. It would be a very beautiful general expression
which in the form of Cy H3:_, O,,, should represent the con-
stitution of all or of one great group of the resins. Our data,
however, are not yet sufficiently extensive to enable us to
form a decided opinion on the subject. In a future paper I
shall give the composition of some other resins, and consider
this point at greater length than it would be proper to do at
the close of the present paper.

Durham, Dec, 6, 1838.

XIX. Meteorological Observations during a Residence in Co-
lombia between the Years 1820 and 1830. By Colonel
Ricuarp Wricut, Governor of the Province of Loxa,
Confidential Agent of the Republic of the Equator, Sc. &c.

{Continued from p. 18.]

ALTHOUGH it scarcely falls within the limits of a mere
meteorological journal to expatiate on the wide field of
inference which opens to our view when we reflect on the
influence of temperature, not merely on animal but on social
life, yet the operation of local circumstances has been so
striking, and will probably play so important a part in the
future destinies of the South American continent, that it is
difficult to forbear some remarks on so interesting a subject.

96 Col. R. Wright’s Meteorological Observations made

Climate is one of the first agents which operates upon the
propagation of the human race over the face of the globe,
presenting itself sometimes as a benignant conductor, at
other times raising a hostile barrier which science and in-
dustry slowly overcome. The Spaniards who peopled that
part of South America now under consideration, as soon as
they had formed on the coast the establishments necessary to
preserve their connexion with the mother country, seem to
have traversed hastily the fertile but insalubrious lowlands to
meet on the Cordillera a temperature adapted to their habits
and constitutions. The dominion of the Incas had, upon si-
milar principles, extended itself along the immense ridge;
and the descendants of the conquerors and conquered are, to
this day, found united on the same elevations, from whence
the population has descended gradually into the plains; and
would have done so much more slowly, but for the importation
of the African race, who find on the sandy coast and sultry
savana a climate congenial to their constitution. It may
be a matter of curiosity to inquire, why that portion of the
bronzed race which constituted the empire of the Incas and of
the Lipas has constantly exhibited a constitutional type so dif
ferent from the tribes of the same race now thinly scattered
through the plains and valleys. The dominion of the Incas
could scarcely be said to have established itself in the low-
lands. With the exception of the dry narrow tract of the
Peruvian coast, their empire was exclusively of the moun-
tains; and the Indians who speak the Quzchua, or general
language of the Incas, still manifest the same preference for
cold and elevated situations; sleeping in the open air rather
than under a roof, and exhibiting an insurmountable repug-
nance to descend into the hot country, where they fall victims
more rapidly than even the Europeans. ‘The latter, although
commercial interests have led them to form establishments
on the coasts, and more partially on the great rivers, may be
said to live in a state of perpetual hostility with the climate.
Their complexions become sallow, their frames feeble; and
although, where heat is uncombined with great moisture, as
in Cumana, Coro and Maracaybo, they are subject to few
diseases of a violent character, the strength is gradually un-
dermined, and the species may be rather said to vegetate than
to increase. The individuals of African race, who complain
of cold when the yearly mean is 75°, alone develope all the
physical strength and energy of their character in the hot
lowlands of the coast and interior. ‘The mixed race, or peo-
ple of colour, unite to bodily hardihood intrepidity, ambition,
and a deadly feeling of those prejudices which, in spite of
laws, continue to separate them from the white descendants of

in Colombia between the Years 1820 and 1830. 97

the Spaniards, who thus encounter, both in the high and low-
lands, two races in whom the seeds of hostility have been
sown by injustice, and fostered by mistaken feelings of interest
and vanity*. It is on the mountain slopes of from 3000 to
7000 feet that we encounter climates most analogous to our
ideas both of health and pleasure. Raised above the noxious
miasmata of the coast, we dwell in perpetual summer amid the
richest vegetable productions of nature, amid a continued
succession of fruits and flowers. This picture however must
not be considered as universally exact. In those unbroken
forests where population has made little progress the sky is
often clouded, and the soil deluged with continual rains.
The western declivities of the Andes, which front the Pacific,
are particularly exposed to this inconvenience.

It might be expected that with regard to human life and
vigour, the elevated plains of the Andes would correspond
to the northern countries of Europe. This however, as far
as regards the inhabitants of European race, does not seem
exactly to take place. It is true they escape the bilious and
intermittent fevers so prevalent in the lowlands; but they are
generally subject to typhus, dropsy, goitre, and such com-
plaints as indicate constitutional debility. Nor do we find
among them either the muscular strength or longevity of the
Indians or Africans; and still less of the nations of northern
Europe. Are the diurnal changes of temperature to which
they are exposed Jess favourable to health than the alternation
of European seasons which expose the frame to changes
equally great but less rapid? Or must we rather look for
the cause in their domestic habits, which exhibit a strange
mixture of effeminacy and discomfort?

When we examine the social or political effects of climate
and localities, we are struck with their powerful effects on the
past struggles and present state of the country. ‘The cities
of the coast must be considered as the inlets both of European
products and European ideas. Liberal opinions have ex-
tended themselves towards the interior in proportion to local
obstacles, i. e. to the greater or less facility of communication.
It is this circumstance which marks the difference betwixt
Venezuela and the south and centre of Colombia, indicating
a distinct and more rapid career of civilization and pros-
perity. The branch of the Andes which traverses Venezuela
is much inferior in elevation to the ridges of Quito and New

* It is the people of colour, or mixture of Africans with Whites and
Indians, who on the plains form the most hardy and warlike part of the
population of Colombia.

Phil. Mag. S. 3. Vol. 14, No. 86. Feb. 1839. H

98 Col. R. Wright’s Meteorological Observations made

Grenada. The whole of the inhabited part of it belongs to
the hot country or temperate mountain zone. The following
are the heights of the principal towns through its whole ex-
tent:

Caracas ......... 2903 ft. Mean temp. 71°

Valencia... 1495 —_—_-_ 78

Barquisimeto... 485 ———_ 78

Tocuyo sso. 2058 — 75

Truxillo......... 2684 — ‘75

Merida ......... 5280 ———-_ 66

Cucuta about 400 ———_ 83

The differences of climate and productions betwixt the dif-
ferent parts of the country are consequently trifling, and form
no bar to general communication betwixt the coast and in-
terior. There is therefore an amalgamation of ideas, an ho-
mogeneity, if we may use the term, in the mass of feelings
and opinions on political subjects. ‘The population is not
only more enlightened, but, what is of more importance, more
equally so. A different state of things presents itself when
we examine the centre and south. The main ridge of the
Andes ascends rapidly from the frontier of Venezuela, and,
by its direction from north to south, places the population at
a continually increasing distance from the sea-ports of the At-
lantic; while its superior elevation producing a different cli-
mate and temperature, gives birth to new habits and a distinct
nationality. ‘To descend to the coast from these altitudes is a
matter both of risk and difficulty. The line betwixt the
Lianeros and Serranos is strongly drawn, and a separation of
character evident. The country from Cucuta to Bogota
through Pamplona and Tunja has a mean elevation of from
8000 to 10,000 feet, and a temperature of about 59° Fahr.
It is true that Bogota communicates with Europe by the val-
ley of the Magdalena; but the length and inconvenience of
this channel of intercourse render it accessible but to few.
Hence the struggle of opinions in New Grenada, where the
civilization of the superior class is out of proportion to that of
the bulk of the people.
The Quitenian Andes afford us another powerful illustra-

tion of this view of the subject. The following is the line of
elevations betwixt Quito and Chimborazo.

Quito) ti sineie? 9687 ft 59° Fahr.
Llactacunga... 10,285 57°
Hambato ...... 61°
Riobamba....... 9377 57°
Guaranda...... 9075 58°

The roads which descend to the coast of the Pacific are

a ee TY

in Colombia between the Years 1820 and 1830. 99

few, almost impassable, and lead to no seaport of importance
except Guayaquil. Journeys thither are undertaken with
fear and hesitation; and the character of the Serranos is
marked with all the traits of isolation resulting from the geo-
graphy of the country.

Next to the direct influence exercised by climate on the
frame of man, we may consider it relatively to the facility it
affords of nourishing him, and advancing his progress in ci-
vilization. ‘The most important presents made by the Old to
the New World -are cattle and cerealia. The only domesti-
cated quadruped known to the Indians was the llama, which
furnished, like the sheep, with thick wool, unwillingly de-
scends or is propagated in the sultry lowlands. The horned
cattle of Europe, on the contrary, have multiplied almost
equally on the plains as on the paramos. On the farm of
Antisana, for instance, at an elevation of from 12,000 to 16,000
feet, there are no less than 4000 head. The herds raised on
the plains of Venezuela, as on the Pampas of Buenos Ayres, are,
or were, previous to the revolution, almost countless. Two
immense magazines of animal food are thus placed at the two
extremes of temperature, in situations uninterfered with by
agricultural labour. The horse has been destined to figure in
the political changes of the New World. The fear and respect
with which he inspired the natives at the period of the Con-
quest iswell known. Horses have since multiplied prodigiously
in all parts of the country, but more especially in the plains
of Venezuela. There, during the war of independence, Paez,
and other guerilla chiefs, “at the head of an irregular cavalry,
and maintained by the cattle, defied the efforts of the Spanish
infantry, and kept alive the embers of the revolution.

The best kinds of horses are those that are bred in the
lowlands, and brought to the mountains at about four years
old, where they acquire hardihood by the influence of a colder
climate, and their hoofs, accustomed only to soft pastures, are
hardened on a stony soil.

The breed of sheep, like that of llamas, is limited to the
loftier regions of the Cordillera; while goats multiply more
readily on such parts of the low country as are both hot and
barren, as in the province of Coro, where they form the chief
wealth of the inhabitants.

But while nature facilitates the dispersion over the globe of
certain species of animals, she seems to limit others by an
impassable barrier. The dog undergoes the fate of his Ku-
ropean master; his sagacity and strength decay in a hot cli-
mate, and the breed dwindles rapidly into an animal totally

inferior in habits and organization. ‘The foresters accord~
H 2

100 Col. R. Wright’s Meteorological Observations made

ingly, and the Indians of the lowlands, who are accustomed
to the chace of the wild hog, bring dogs for the purpose from
the mountains, where, though the Spaniards are by no means
curious in this particular, a strong species of greyhound, more
or less degenerated, is to be met with, and is used in the high-
lands for stag-hunting.

The influence of temperature, and consequently of local
elevation, on vegetable life, was first examined in Colombia
by a native of Bogota, the unfortunate and illustrious D. José
Caldas, who fell a victim to the barbarity of Murillo in 1811,
in consequence of which his numerous researches in natural
history were almost entirely lost, with the exception of some
papers published in the Seminario de Bogotd in 1808, and
fragments still existing in MS. or casually preserved and
printed in Europe, to one of which I shall presently have oc-
casion to refer. Humboldt travelled through South America
about the same time that Caldas was directing the attention
of his countrymen to physical science, and his investigations
have fortunately been subjected to a less rigorous destiny.
His admirable treatise ** De distributione Plantarum geogra-
phica,” has left for future observers little but to corroborate
the accuracy of his views, and multiply facts in illustration of
his theories.

When we begin our observations from the level of the sea
we find certain families of plants which scarcely ever rise to
above 300 or 400 feet; the ‘* Sandalo” producing the balsam
of Tolu, the Lecythis, the Coccoloba, the Bombax, the Rhizo-
phora Mangie, the Manchineel. A second and more nume-
rous class push on to about 2000 feet of elevation; such are
the Plinia, the ‘ Copal,” the Anime,” the ‘ Dragon’s
blood,” the mahogany tree, the ‘“ Guayacdn.” Among
plants, the Cesalpinia, Ipomea quamoclet, most of the Bz-
gnonias, Portlandias, the Vanilla, Cassia alata and ripa-
ria, the Pontaderia, which forms the ornament of tropical
rivers. The palms ascend to the height of 5000 feet. The
arborescent ferns, from the level of the sea amid the damp
forests of Esmeraldas to 7000 feet. Of cultivated plants the
Cacao and indigo are most limited as to elevation, neither of
which are cultivated with success at above 2000 feet. An
attempt to raise indigo at Mindo (3960 feet) completely failed.
It would seem that a dry climate is most favourable to indigo,
such as is found in the valleys of Aragua near Valencia;
while heat and moisture, as Humboldt observes, are particu-
larly required for cacao. Yet cacao cultivated on lands which
are flooded part of the year, as is the case with the greater
part raised in Guayaquil, is of inferior quality, scarcely pro-

a eh

zn Colombia between the Years 1820 and 1830. 101

ducing in the market a dollar per cwt. That of Esmeraldas,
on the contrary, where notwithstanding the moisture of the
climate the waters never settle on the soil, is of equal or su-
perior quality to that of the valley of Tuy near Caracas. In
Canigue, at an elevation of about 1000 feet, the trees are
loaded with fruit in less than two years from the time of sow-
ing the seed; while generally three years is the period at
which they are reckoned to commence bearing.

Coffee is abundantly raised from the level of the sea to
elevations of 5000 or 6000 feet, or even higher in favourable
situations. ‘There are plantations near the valley of Bafios
in Quito at above 7000 feet.

Cotton requires, according to Humboldt, a mean tempera-
ture of not less than 64°—60°, which would bring it to the ele-
vation of Loxa.

The sugar cane is cultivated in Colombia from the level of
the sea to an elevation, which may appear extraordinary, of
7865 feet in the valley of Baiios at the foot of Tunguragua,
of 8500 in the valley of Chillo below Quito, and of nearly
9000 feet near the town of Hambato. It must be observed,
however, with respect to the latter, that the vegas or nooks
formed by the windings of the river, where alone it is raised,
are so sheltered as to produce an almost artificial tempera-
ture. A palm tree brought young from Guayaquil flourishes
there, and “* Aguacates,” (the fruit of the Laurus persea) ripen
perfectly, with oranges, limes, and other fruits which in ge-
neral are not cultivated at above 6000 feet. In proportion,
however, to the elevation is the time required for ripening the
sugar-cane, varying from nine months at the elevation of
1000 feet, to three years at the elevation above cited.

Plantains and maize are the principal articles of food in
the lowlands or hot country, ‘‘¢éerra caliente,” to use the
expression of the natives. The larger variety of plantain,
** Platano harton,” cannot be cultivated at elevations above
3000 feet, while the smaller variety “ Camburi,” will ascend
to 6000 feet. Maize is perhaps the plant which, of all others,
embraces the greatest variety of temperature and elevation.
It is cultivated with equal advantage from the level of the
ocean to the flanks of the Andes, 0 to 11,000 feet; tempera-
ture 80°—59°. Itis true, that in the lowlands it ripens in
three months, whereas on the table lands of the Andes it re-
quires ten; but the grain is larger, and the ear fuller in the
cold than in the hot country.

The central or temperate zone of the Andes is distinguished
by the Cinchonas, the arborescent ferns which precede and
accompany the palms nearly, and in the moist forests of the

102 Col. R. Wright’s Meteorological Observations made

Pacific, entirely to the level of the sea*. At the back of
Pichincha they first appear about 8500 feet. The Alstra-
merias and Calceolarias, peculiar to the New World, belong
to this zone, though the former ascend to 11,000 feet and the
latter to 15,000.

The Cerealia, with almost all the varieties of European ve-
getables, belong to this region. Humboldt observes a pecu-
liarity that wheat is grown near Vittoria at the elevation of
1700 feet, and in Cuba near the level of the sea; (Geo. Pl.
p- 161) but it is probable that the reason why the cerealia
are cultivated only at elevations where the Muse disappear,
may be the natural inclination of the inhabitants of the warm
country to prefer the cultivation of a plant which yields an
equal abundance of food with infinitely less labour, not only
in the mere cultivation, but in the subsequent preparation.
The three great wheat districts in Colombia are the mountain
chain of Merida, the elevation of which rarely reaches 5000
feet, with a general temperature of 72°; the plain of Pam-
plona, Tunja, and Bogota, elevation 8000 to 10,000 feet;
temperature 58° ; and the Quitenian Andes of the same height
and temperature. Humboldt has accurately observed, (Geo.
Pl., p. 152) that a comparison betwixt annual mean tem-
peratures of Europe and the elevated tropical regions would
by no means give a correct state of the climate. Thus,
though the mean temperature of the South of France and of
Quito be the same (about 59°), such fruits as peaches, apricots,
pears, figs, and grapes, which ripen in perfection in the former,
altheugh abundantly produced in the latter, never attain
their proper size or favour. The reason is that the tempera-
ture is equal throughout the year. There is consequently
no period, as in Europe, of summer heat sufficient to ripen
fruit requiring at this season a mean temperature of 65° or
70°. As far, however, as the height of 7000 feet all kinds of
fruit are cultivated with success; and the markets of the
colder country are thus constantly supplied from the neigh-
bouring valleys or ‘ calzentes.” Humboldt is mistaken in
supposing the olive always barren (semper sterilis manet,
p- 154.).. On the Quitenian Andes near Hambato it produces
abundantly, though little attention is paid to its cultivation.

When we ascend above the extreme limit of cultivation,
which may be placed at 11,500 feet, and pass the region of
the Barnadesia, Hyperica, Thibaudiea, Gaultheria, Bud-
dleia, and other coriaceous leaved shrubs which, at this ele-
vation, form thickets of perpetual bloom and verdure, we

* Humboldt, who had not visited these forests, confines them to betwixt
800 and 260 hexap. De Geo. Pi., p. 185.

in Colombia between the Years 1820 and 1830. 103

enter the region of Paramos (13,000 to 15,000 feet) properly
so called, which present to the eye unvaried deserts clothed
with long grass, constituting the pasture grounds of the Andes.
Humboldt is inclined to fix below this region the limit of
forest trees; (Geo. Pl., p. 148) and in fact very few are gene-
rally met with near this elevation on those flanks of the Cor-
dillera which join the inhabited table lands. But I have
observed on crossing the side of Pichincha, towards the un-
inhabited forests of Esmeraldas, that the forests occur nearly
through the whole space which, on the eastern slope, is a naked
paramo. Is this owing to a difference of climate? Or has the
practice of burning the paramos, universal in the Andes, to-
gether with the demand for fire-wood in the vicinity of large
towns, contributed to give this region the bare aspect it has
at present? Further observations on the mountain slopes
towards Maynas and Macas are necessary to throw light on
this point. It is certain from the present aspect of the inha-
bited plain of Quito, where we meet with a few scattered trees
of Arayan (Myrtus) and artificial plantations of Capulz,( Prunus
salicifolia) we should conclude that the region of forests had
scarcely ascended to the height of 8000 feet, yet some of the
houses of Quito are still standing, built with timber cut on
the spot.

A circumstance which cannot have escaped the notice of
those who have ascended towards the limit of perpetual snow,
is the variety and luxuriance of the Flora at the very point
where the powers of vegetation are on the brink of total sus-
pension. At above 15,000 feet the ground is covered with
Gentianas, purple, azure and scarlet; the Drabas, the Alche-
millas; the Culatium rufescens with its woolly hood; the rich
Ranunculus Gusmanni; the Lupinus nanus with its cones of
blue flowers enveloped in white down; the Sida Pichinchensis
spotting the ground with purple ; the Chuqueraga insignis ; all
limited within a zone of about 500 feet, from whence they
seem scarcely to be separated by any effort at artificial culti-
vation. Several attempts I have made to raise the Gentians,
Sida, and other plants of the summits of the Andes, at the
height of Quito, have been invariably unsuccessful. The
attempts indeed to domesticate plants in a situation less ele-
vated is attended with greater difficulties than the transport
of plants from one climate to another. Besides the difference
of atmospheric pressure, as Humboldt has observed, plants
transferred from one elevation to another never meet, for a
single day, with the mean temperature to which they have
been accustomed; whereas transferred from one latitude to
another, the difference is rather in its duration than in its in-

104 Mr. T. Hopkins’s Observations on Malaria.

tensity. It is easier to accustom a plant of the lowlands to
this elevation than to bring down those of the paramos. ‘Thus
the orange and lemon trees, Aguacates (Laurus persea) Iti-
cinus communis, Datura arborea, all natives of the hot low-
lands, grow and flourish, more or less, at an elevation of
8000 feet above the level of the sea.

[To be continued. ]

XX. Observations on Malaria, with Suggestions for ascertain-
ing its Nature: read before the Literary and Philosophical
Society of Manchester, November 15, 1838. By ‘THomas
Horkins, Esq.*

N ALARIA is considered the scourge of a considerable

portion of Italy, where it is spoken of with an undefin-
able feeling of horror. It is not, as its name may seem to
imply, supposed to be simply bad air, but a poisonous efflu-
vium arising from some undiscovered operation of nature,
and known only through its dreadful effects on human beings.

The volcanic nature of the country, the gases thrown from its

surface by the agency of internal heat, with their offensive

smells, are in the imagination of the people connected with
the cause of marsh fever, and designated by the word Mal-
aria. The author of the description of Latium speaks of
the volcanic soil being prejudicial to the atmosphere; and
Mrs. Starke, in her account of Rome, talks of the sulphur,
arsenic and vitriol which abound, producing malaria. This
lady may be considered as speaking the ordinary language of
the people of the country on the subject. Learned writers too
have treated of malaria in a way almost equally mysterious,
among whom may be named Dr. Macculloch. The Doctor
does not indeed suppose that sulphur or vitriol is instrumental
in producing the poison, but that it is the product of vege-.
table fermentation or putrefaction, the form and mode of
operation of which we are not able to trace, becoming con-
scious of its existence only by witnessing its effects. ‘The
pest is shown to be worse in Italy than in other parts of

Europe, but the Doctor has shown that it really prevails in

other countries, and to a greater extent than had been pre-

viously suspected. Whatever may be the peculiar nature of
malaria, Dr. Macculloch seems satisfied that it does not arise
from the presence of minerals, nor from local causes confined

* Communicated by the Author. The reader may advantageously
compare this paper with Mr. Addison’s “* Remarks on the Influence of Ter-
restrial Radiation in determining the site of Malaria,’ Phil. Mag. and An-
nals, N.S., vol. iv. p. 272, e¢ seg —Enir.

Mr. T. Hopkins’s Observations on Malaria. 105

to any particular country. It is indeed distributed extensively
over the surface of the earth. Asia, Africa, and America feel
the scourge in a more violent degree than it is felt in any part
of Europe: the plains of Bengal, the vallies of the African
coast, and the West Indian islands are infected in a more
deadly degree than even Italy; it is therefore reasonable to
infer that the locality of gases or minerals is not connected
with its production. It is found too in climates having dif-
ferent temperatures to those of the countries just named, as
on the eastern coast of England, in France, and Holland:
very high temperature therefore does not seem essential to its
production. But though not absolutely requisite to its pro-
duction, high temperature appears to increase its virulence,
the injurious effects on the human constitution having a pal-
pable relation to the temperature of the atmosphere. Thus
in Lincolnshire, France, and Holland, its operation is slow,
and it requires considerable time to produce fatal effects ; but
in the Campagna of Rome, it is said that a single night passed
within the full influence of the pest endangers life. In the
jungles of Bengal it is fully as bad as in the Campagna, and in
the vallies of the western coast of Africa the greater number
of the crew of a ship have been known to die in a short time.
Thus it becomes apparent that the virulence of the fever
arising from malaria is great in proportion to the heat of the
climate.

Yet great heat alone does not seem capable of producing the
poison. However high the temperature may be, provided
it is not accompanied by moisture, the air is found to be
healthy. The plains of Russia are hotter in summer than the
marshes of Holland, but no malaria is found in the former,
while it abounds in the latter, because the plains of Russia
are dry as well as hot. Rome is only seven degrees hotter
than Moscow in the hottest month of the year, yet malaria
is virulent in the one, while it does not exist in the other. In
the sandy deserts of Asia and Africa we have perhaps the
hottest climates of the globe, but as these deserts are at the
same time dry malaria is not prevalent in them. ‘The infer-
ence is that heat alone will not produce malaria, but that the
presence of moisture also is necessary.

Dr. Macculloch admits, * that the extreme of evil from
malaria occurs in tropical climates, it appearing almost pro-
portioned to the heat of the climate, and, what is important
to observe, to the moisture also.” He also remarks that
* Egypt is free from the fever arising from malaria except at
the period of the subsidence of the Nile, unless where, as at
Damietta, the cultivation of rice is pursued.” But the Doctor

106 Mr. T. Hopkins’s Observations on Malaria.

afterwards attempts to show that heat and moisture are merely
agents in the production and distribution of a poisonous ex-
halation from vegetable matter, which exhalation he says is
the true malaria. A moist air, says he, ‘is the best con-
ductor of the malaria, as moisture in the air, under the form
of evening mists or in other modes, appears to be even its
proper vehicle or residence.” And again he says, ‘‘ water
in some form is necessary to the production of that peculiar
vegetable decomposition which is the source of this poison ;
and the action of moisture is twofold, inasmuch as it not
only accelerates vegetable decomposition, but renders the at-
mosphere a fitter conductor of the poison.” It is not here
pretended that this poison which is stated to be the result of
vegetable decomposition has ever been detected in a palpable
form. It is not asserted that its existence as a peculiar sub-
stance has been ascertained. It is only from effects produced
on human health that its existence is inferred. Moisture, says
the Doctor, is not capable of poisoning the atmosphere; and
as he finds that the atmosphere is poisoned, he infers that
the poison is exhaled in the decomposition of vegetable sub-
stances.

There is a prevalent belief in many parts of the world that
fogs coming from the sea produce fevers of the same kind as
the malaria fever: this belief is evidently at variance with the
theory espoused by Dr. Macculloch, and he thus reasons with
those who entertain it. ‘* The proof that it is malaria in the
fog, and not the fog itself which is the cause of disease, is
evinced by the following facts: No intermittents are ever
preduced on the western or northern shores of the island, and
for the plain reason that there is no land whence they may
arrive. ‘The clouds of mountainous regions do not produce
fevers though these are also fogs; and what forms a most ab-
solute proof of this is, that in Flanders it is the fogs which
come with a south-west wind or the southerly winds which
transport and propagate malaria and diseases, while as soon
as the winds shift and blow from the sea the fevers disappear,
though these particular winds are so charged with fog as to
darken the whole country for days.” These are the facts on
which the Doctor relies, and he remarks, that “ it ought
surely to be unnecessary to say that if fogs alone could pro-
duce such fever water itself must be the poison, since a fog is
a cloud, and its constituents when pure are only atmospheric
air and water.”

With respect to the first alleged fact, that no intermittents
are produced on the western or northern shores of our island,
the reason for it may be found in the circumstances of these

ip es

2 pe aE, le BB

sche. >

one > tp ee re re Sere ere >

Mr. T. Hopkins’s Odservations on Malaria. 107

shores being either rocky, or well drained and under cultiva-
tion, and consequently dry. They are also nearer to the
Atlantic Ocean, and therefore cooler in the summer than the
eastern coast. These two causes may be sufficient to account
for the difference which is found on the eastern and western
coasts of this country. But I have been informed by Dr.
Briggs of Ambleside, formerly resident in Liverpool, that in
his younger days autumnal agues were common on the low
grounds of Lancashire, particularly in that part called the
Fylde country, and that they occasionally prevail at present.
Their diminution may be attributed to the better drainage
of the country, which has converted it from a comparative
marsh to dry tillage land. That the clouds of mountainous
regions do not produce fevers may arise from their low tem-
perature. And as to the fact that south-west and south winds
produce fevers in Flanders, while on a sea wind coming which
coyers the country with fogs the fevers disappear, this may
only prove that the sea wind being a cold one, the reduction
of the temperature caused the fever to cease. The Doctor
seems to think that there is great force in the remark “ that
if a fog alone could produce fever water itself must be the
poison:” but the argument may not, as we shall presently
see, turn on the water in the atmosphere as water, but as
steam or elastic vapour. And it may be found that when
there is a certain quantity of steam in the atmosphere at a
high temperature, disease may be a consequence, notwith-
standing that water is wholesome in a liquid state. Dr. Mac-
culloch’s opinions respecting the cause of malaria are at vari-
ance with numerous and well ascertained facts. This pest
is found on sea borders and islands, as on the coasts of
Italy and Africa, on the small Maldive islands in the Indian
Ocean, in the West Indian islands, even in Barbadoes, which
pushes out east a considerable way into the Atlantic; it is also
found at sea at great distances from land, and beyond the
reach of effluvia from vegetable putrefaction. In the valuable
statistical report of sickness and mortality among the troops
in the West Indies, recently laid before the House of Com-
mons, it is said, when speaking of the hypothesis of vegetable
exhalation producing malaria,—‘“ Were this hypothesis cor-
rect, we might expect that British Guiana would, from its
proximity to this cause of disease, be most subject to its ope-
ration, and consequently the most unhealthy, and that the
colonies further to the north, being least exposed to it, would
enjoy the greatest degree of salubrity. ‘The result of our in-
vestigations into the comparative mortality in each colony
shows however that their relative salubrity is by no means

108 Mr. T. Hopkins’s Observations on Malaria.

affected by their proximity to, or distance from, the conti-
nent.” (See table of relative mortality at the end.)

The atmosphere in which we live, it is well known, has
within it azotic gas, oxygen, a small portion of carbonic acid
gas, and invisible vapour of water, or steam. The nature of
the three first-named substances, as far as respects their in-
fluence on animal life and health, is tolerably well known ;
but the same cannot, I believe, be said of the steam which
exists in the atmosphere; nor am I aware that any scientific
attempt has been made to trace its influence on the animal
ceconomy with relation to health and disease. It is known
that too dry an atmosphere is productive of unpleasant
and sometimes of very painful consequences. [Evaporation
from the body goes on so freely as to deprive it in too great
a degree of moisture and to produce a constant thirst. A
certain degree of moisture in the air keeps the body soft and
gives that clearness of complexion common in many parts of
the north-west of Europe, which is supposed to indicate vi-
gorous health. But in other parts of the world there is,
with reference to the animal ceconomy, a superabundance of
steam in the atmosphere. This is popularly recognised in
those parts when it takes the form of dampness, as it is then
thought to be injurious to health; but it has not been treated
of scientifically. In the absence of any treatise on the sub-
ject I propose to call attention to a few points, in the hope
that it may induce others to institute a full inquiry, meteoro-
logical, chemical and physiological, such as the important
nature of the subject demands.

Let us imagine that at some certain time no vapour exist-
ed in the atmosphere: according to the known laws of eva-
poration vapour would immediately begin to arise from all
wet surfaces ; and supposing evaporation to proceed, the whole
of the space occupied by the atmosphere would soon be filled
with vapour, or invisible steam ; the quantity being propor-
tioned to the temperature of each particular place. Where
the temperature was low there would be but little steam,
where it was high there would be more, and every part would
in time have its maximum quantity, when of course no more
could rise. In this state, as there would be no condensation
of vapour, there would be no clouds and no rain. But owing
to the unequal influence of the sun on different parts of the
earth’s surface, and the diurnal motion of the globe, this
state of things does not exist. Between the tropics the sun
vaporises water freely, and at the same time by its heat
rarefies the air. The vapour ascends with the rarefied air
to the upper regions of the atmosphere, cold air flows in below

SS

Mr. T. Hopkins’s Observations on Maluria. 109

from parts nearer to the poles, and the process.is repeated and
continued. The vapour that is taken up with the rarefied
air flows with it through the higher region towards the poles,
and becoming cooled in its passage, a portion of the vapour
is deposited in the form of rain. The air thus cooled and
deprived of part of its vapour returns from each polar region,
flowing along the surface of the earth, and has its temperature
increased by the sun’s heat as it advances towards the equator ;
it consequently becomes a dry air, or is disposed to take up
vapour from moist surfaces. ‘Thus we see that in accordance
with the general laws of nature, the air near to the surface of
the earth which is flowing from the poles to the equator is a
dry air.

But through the influence of local causes this course of
nature, though general, is not universal. While in some parts
the air near the surface of the earth is very dry, in other
parts itis so fully charged with mvisture as to prevent further
evaporation taking place at the existing temperature. In this
case, the dew-point, being that degree of the thermometer at
which dew is formed from the atmosphere, is the same as the
temperature. In different parts of the world there are various
degrees of dryness in the atmosphere, and these are expressed
by the relation which the dew-point bears to the temperature.
When the dew-point is only one degree below the tempera-
ture evaporation goes on very feebly; when more than one,
it proceeds more vigorously; when at ten, fifteen, or twenty
degrees below the temperature, evaporation goes on with pro-
portionally increased energy. Dr. Dalton made various ob-
servations on the subject near to and on the mountain of Hel-
vellyn in Cumberland. He found that at one time, in the
valley below the mountain, the temperature was 70°, the dew-
point 53°, difference 17°; at another time the temperature was
56°, the dew-point 46°, difference 10°: of course the energy
of evaporation would in each case be proportioned to the dif-
ference. At the same time, on the mountain, 855 yards above
the valley,the temperature was the first time 56°, dew-point
46°, difference 10°. The second time it was 46°, dew-point
42°, difference 4°.

Thus in these four observations the energy of evaporation
would be as the numbers of the difference, or as 17, 10, 9,
and 4. In the same paper in which the above facts are to
be found, published in the 4th volume of the Society’s Trans-
actions (Manchester) the Doctor has given a table of numbers
exhibiting the drying power of the atmosphere, which is one
form of expressing the energy of evaporation.

5
Dr. Dalton also states that in twenty years of observation

110 Mr. T. Hopkins’s Observations on Malaria.

chiefly at Manchester, he found that in the months of June,
July, and August the dew-point generally ranged from 50° to
60°; that it was only once at 64°, once at 63°, five times at 62°,
three times at 61°, and twenty times at 60°. But in other parts
of the world where malaria prevails, different meteorological
facts present themselves, and furnish ground for presuming
that the laws of evaporation affect the people of those coun-
tries differently to what they do the inhabitants of our colder
climate. In Rome, in the hottest month of the year, du-
ring the day the temperature ranges from 90° to 100° in the
shade, and the air is damp; the dew-point must therefore be
high.

is Captain Alexander’s observations on the western coast
of Africa, we are told that ‘ four days after leaving Teneriffe,
while proceeding for the river Gambia, on the 6th of October,
the wind at south-east swept over the ocean charged with
moisture. At noon the thermometer under the awning was
at 80°, while with Daniell’s hygrometer I found the dew-point
at 70°. On the 7th of October during a sirocco the thermo-
meter was at 86°, the hygrometer 76°. At the end of Novem-
ber in the Bight of Benin, in sight of the island of St. Thomas,
the temperature was 84°, the hygrometer 79°!” In the me-
teorological register kept by Mr. Oldfield, surgeon in Laird
and Oldfield’s expedition up the Niger, we find it stated that
during the month of April, on the river, the temperature was
generally above 100°, and on the 14th of April it reached
118°. No hygrometrical return is given, but as the air is
stated to have been damp, it may safely be inferred that the
dew-point was extremely high,

Here then we have instances where the dew-point was in
different places at the respective heights of 42°, 46°, 53°, 60°,
70°, 76°, and 79°, and from Oldfield’s register it may be pre-
sumed to have been much higher on the Niger, probably 90°.
Suppose water of the temperature of 98° to be placed in these
various atmospheres, and it will be seen that the energy of
evaporation of this water would be very different in those dif-
ferent places. Evaporation would go on much more freely
when the dew-point was at 42° than when at 60°, at 60° than
when it was at 70°, at 70° than 76° or 79°; and the nearer the
dew-point approached to 98°, the temperature of the water, the
more feeble would be the evaporation. . Now the temperature
of the human body in its healthy state being 98°, when this
body is placed in an atmosphere the dew-point of which is
42° or even 60°, evaporation will go on vigorously. Let the
dew-point rise to 70°, and still evaporation might possibly
go on with considerable energy; but should the dew-point

Mr, T. Hopkins’s Odservations on Malaria. 111

be raised to 80° or 90°, evaporation from the body must be-
come very feeble.

In a paper read March 1830, and printed in the 5th vol.
of the Society’s Transactions, Dr. Dalton has shown that a
healthy man taking daily into his stomach 53 ounces of fluid
gives off from the external skin in the same time 63 ounces
of water, and from the lungs 203 ounces, making together 273
ounces. Now is it not clear that this important process in
the animal ceconomy must be variously affected by the hygro-
metrical state of the atmosphere ; differently when the dew-
point is at 50° to what it will be when at 60°, 70°, 80°, or 90°?
Were the dew-point to be carried up to 98°, this process, it
would appear, must stop, evaporation would cease, and the
27% ounces of water would remain in the system, or be dis-
posed of by nature in some different mode, which would
constitute a material derangement of the animal ceconomy.
Again, it requires a considerable portion of caloric to va-
porise 27; ounces of water; and when this quantity of water
is daily thrown off by evaporation, it is presumed that the re-
quisite quantity of caloric is abstracted from the human body.
Evaporation seems indeed to be the agent that nature em-
ploys to regulate the temperature of the body, and when it is
stopped or materially impeded fever generally ensues, the tem-
perature of the body rises, and from 98° goes up at last to fever
heat or 112°. Lavoisier and Seguin estimated the average
loss by perspiration from the skin and lungs in twenty-four
hours at 2 pounds 13 ounces, of which 1 pound 14 ounces
were dissipated by the skin, and 15 ounces by the lungs.
(Traité Elémentaire de Chimie, 3™¢ édition, 228.) The de-
gree of dryness of the atmosphere may, it is obvious, in-
fluence the whole quantity evaporated, and also the pro-
portions given off respectively by the external skin and
lungs.

Malaria seems not to prevail in a virulent state where the
dew-point is below 60°. In Lincolnshire and parts of Hol-
land and of France the dew-point is probably sometimes
above that height towards the end of the summer: in those
countries malaria fever prevails in its mildest form, but al-
ways at those periods when the dew-point is presumed to be
the highest. In the maremma of Tuscany, the Campagna of
Rome, and other parts of the south-west coast of Italy, in the
latter part of the summer the dew-point must be high, and
precisely at this period of the year in these places malaria
prevails, andin the worst form in the hottest and dampest
parts. In the West Indies, in Bengal, and in the African
valleys the same facts are observable; malaria is always viru-

112 Mri. Hopkins’s Observations on Malaria.

lent in proportion to the height of the dew-point. It is how-
ever greatly to be lamented that we have not more particular
and full hygrometrical returns of the state of the atmosphere
in those parts of the world; were we furnished with such re-
turns, there is little reason to doubt that it would be easy
to show, by the evidence of facts, that there is such a general
coincidence of a high dew-point and the prevalence of malaria
fever as would place them in the relation of cause and effect.
In the returns from the West Indies, published in the Stati-
stical Report of the mortality there, we have a monthly hygro-
metrical return for the year 1832, from the island of St. Vin-
cent: it is the only one in the whole report, and the substance
of it is given at the end. It will be seen from this that the
mean of the dew-point for the year is 68°°86 ; the lowest, in
the month of February being 67°14, and the highest, in July,
70°25.

From tiie laws of evaporation as ascertained by experience,
it is known that the rest or motion of the air has considerable
influence on evaporation from wet surfaces. When vapour
rises from these surfaces it remains for some time resting upon
and near to them, where it checks further evaporation. But
when a current of air by its mechanical action carries away
the newly formed vapour, fresh vapour immediately escapes,
and the process is repeated : the influence of winds in drying is
a familiar instance of this fact. The human body is disposed
to give out vapour to a given extent to an atmosphere, the dew-
point of which is, say 70°; but without motion in the air the
vapour first given out would impede further evaporation; a
wind removes this impediment and suffers the evaporation to
go on more freely. In accordance with this it is known that
malaria fevers more commonly prevail in a warm damp atmo-
sphere when it is stagnant! A brisk wind is said popularly to
purify the air, and to take away mephitic vapours; may it not
merely facijitate evaporation? Persons suffering under mal-
aria fevers are relieved by fanning! Were the air charged
with poisonous vegetable miasmata, it would be reasonable to
conclude, that fanning, by bringing more of this poisoned air
into contact with the patient, would increase the disorder !
But if the view here taken be correct, the cause of the relief
that is felt becomes sufficiently obvious; the evaporation
which was checked by the previous accumulation of vapour is
accelerated by its removal.

In temperate climates the heat of the atmosphere is consi-
derably below that of the human body, and the dew-point is
ordinarily below the temperature of the atmosphere. But
with reference to perspiration it seems to be as important that

cy
7
|

Mr. T. Hopkins’s Observations on Malaria. 113

the dew-point should be below the temperature of the atmo-
sphere, as that the temperature of the atmosphere should be
below that of the human body, unless the temperature be
very low. The temperature and dew-point being the same,
and at 60°, evaporation would not proceed rapidly from the
human body in astagnant atmosphere. But if a much colder
atmosphere, say 40°, were to be fully saturated, the body
being 98°, would warm the air immediately around itself, give
it a capacity to take up more steam, and at the same time
create a more decided upward current that would continually
change that part of the air which was in immediate contact
with the body.

Writers and travellers when speaking of a damp atmosphere
commonly restrict their remarks to those atmospheres which
discharge rain, or are charged with fogs, their object being
generally to intimate that such atmospheres wet or moisten
substances exposed to them. But an atmosphere may be sa-
turated with steam, without giving out any part of it to sub-
stances immersed in it which are of an equally high tempera-
ture. Suppose both the temperature and the dew-point to be
70° during the night, neither rain would fall nor dew be
formed, and yet with reference to evaporation it would be a
damp atmosphere, seeing that no evaporation could take place
in it from water of the same temperature. It is the existence
of transparent elastic steam in certain quantities in the atmo-
sphere which prevents further evaporation from wet surfaces,
and it is this steam we have now under consideration, and not
either the fall of rain or the floating of condensed vapour.
These are effects of this elastic steam having previously ex-
isted ; but it is the steam itself of which we are now treating,
and of its effects in checking evaporation. An atmosphere
of the temperature of 118°, as found by Oldfield in Africa,
might possibly have a dew-point of 98°, and would conse-
quently have a drying power of 20 degrees, but the trans-
parent elastic steam in this atmosphere would put an entire stop
to evaporation from the human body, seeing that the tempe-
rature of that body in a healthy state does not rise higher
than 98°. It is therefore necessary to observe that it is neither
the rain that falls, nor the condensed vapour that floats in
damp climates where malaria prevails, that is here supposed
to constitute that malaria, but solely the quantity of invisible
steam which, by its mechanical pressure on the surface of the
skin and lungs, prevents the ordinary process of healthful
evaporation from being continued, and thus this invisible
steam becomes the real malaria. When this steam stops eva-
poration from the body, the 271 ounces of water previously

Phil. Mag. S. 3. Vol. 14. No, 86. Feb.1839, I '

114 Mr. T. Hopkins’s Observations on Malaria.

thrown off by evaporation remains in the body, with the heat
requisite to evaporate it, and this may cause fever, and carry
the temperature of the body up to 112°,

The evidence of what is called dampness of the atmosphere,
as given by writers generally, is of a loose and unsatisfactory
nature. Even in the valuable report from the West Indies
already alluded to, the intelligent compiler says: “ If the
mortality of the troops depended materially on the influence
of moisture, we might expect it to attain its maximum in those
stations where the greatest fall of rain takes place, whereas
the average mortality of troops in Jamaica is at least double
that which prevails among those in British Guiana, though
the quantity of rain which falls in that island is little more
than one half as great as in Guiana.”

Here we see that the quantity of rain that falls is taken
as evidence of the moisture of the climate, whereas it is quite
possible that rain may fall from a considerable elevation while
the dew-point is comparatively low near the surface of the
earth, while on the other hand the dew-point may be very
high without much rain falling. When the autumnal rains
fall at Rome malaria is diminished, but those rains by cooling
the country lower the dew-point or reduce the quantity of
steam in the air. In the summer in Great Britain the dew-
point is at times 15 or 20 degrees below the temperature
when clouds are forming and rain falling from a considerable
elevation. The fall of rain is evidently not an indicator of
the state of the dew-point near the surface of the earth.

In directing our attention to this subject it may be worth
while to observe, that it is not so much the mean temperature
of certain places that should be noticed, as the high tempe-
rature of the days vaporising much water, and thus raising
the dew-point very high. A temperature of 100° in the day
and 60° at night, making a mean of 80°, might in a marshy
country, such as that near Rome, give a dew-point of, say
90°, at or near sunset, while a uniform temperature of the
mean 80° could not possibly give a dew-point of 90°, nor
above 80°. A day temperature of 70° and a night tempera-
ture of 40°, making a mean of 55°, might give a dew-point of
60°, but a uniform temperature of the mean could not give
so high a dew-point as 60°. As the former may be taken to
represent the Campagna of Rome, the latter may be consi-
dered to represent the marshes of Lincolnshire. Now when
on the going down of the sun the temperature of the Cam-
pagna sunk to 90°, the temperature and the dew-point.might
be the same; and when in Lincolnshire the temperature sunk
from 70° to 60°, the temperature and dew-point might also be

Mr. T. Hopkins’s Observations on Malaria. 115

the same. But the dew-point the same as the temperature
even at 60°, with a stagnant atmosphere, might seriously check
evaporation from the human body, though not to the same
dangerous extent as the higher dew-point in the Campagna
of Rome. }
Captain Cook and others experienced the unhealthy in-
fluence of hot and damp air at sea, far removed from the sup-
posed seats of poisonous effluvia from decaying vegetable sub-
stances, and also found the benefit of heating and drying the
air. In Cook’s Voyage from 1772 to 1775, p. 9, it is stated
that, “ in latitude 3° north, August 20 to 27th, the thermo-
meter generally at noon kept from 79° to 82°. On the 27th
spake with Captain Furneaux, who informed us that one of
his petty officers had died. At this time we had not one sick
on board, though we had everything of the kind to fear from
the rain we had had, which is a great promoter of sickness in hot
climates. ‘To prevent this I took every necessary precaution
by airing and drying the ship with fires made between decks,
smoking, &c. &c.; neglect of these seldom fails to bring on
sickness, but more especiaily in hot and wet weather.” And
in page 291, vol. ii. ** Care was taken to keep the ship clean
and dry between decks, Once or twice a-week she was aired
with fires. I had also frequently a fire made in an iron pot
at the bottom of the well, which was of great use in purifying
the air in the lower part of the ship.’ Sir J. Pringle in his ac-
count of Cook’s sanatory precautions, says, that “some old
ships were more healthy than the new ones, because the
former having their galley in the forepart of the orlop, the
chimney vented so ill, that it was sure to fill every part with
smoke. This was a nuisance for the time, but, as he thought,
abundantly compensated by the extraordinary good health
_of the crews.” Perouse, when proceeding from the northern
part of the Pacific to the Equator, and in the latitude of 10°
north, writes thus: ‘The heat was suffocating and the hy-
grometer had never indicated more humidity since our de-
parture from Europe. We were breathing an air destitute
of elasticity! which joined to unwholesome aliments dimi-
nished our strength, and would have rendered us almost in-
capable of exertion if circumstances had required it. I re-
doubled my care to preserve the health of the crew during
this crisis produced by too sudden a passage from cold to heat
and moisture, I ordered the ship to be dried and ventilated
between decks.” A high dew-point, no doubt, was here the
cause of the illness, and the drying was merely heating the
air so as to carry the temperature much above the dew-point.
On the 20th of January the brothers Lander sailed in the
LG

116 Mr. T. Hopkins’s Observations on Malaria.

ship Carnarvon from the island of Fernando Po, having “a
crew of seven European seamen, two free negroes, one Kroo-
man, one captain and two mates. Two of the seamen were
ill of fever, Owen Williams and C. Hall. On Sunday, Ja-
nuary 23, one of the sick seamen died. On January 26,
three of the healthy men, namely, the steward, the second
mate and a seaman, were taken ill of fever. January 27th,
a seaman taken ill of fever. The weather calm, with light
winds ; the island still in sight! January 30, another seaman
taken ill of fever. The steward died. ‘Februar y 4, the cap-
tain taken ill. John Williams died. February 6, the chief
mate taken ill of fever. February 7, Smith, seaman, died.”
Here there was doubtless a high ‘dew-point, and the tempe-
rature was not, as in the instances of Cook and Perouse, raised
much above it by fires. It would be very easy to give ample
additional evidence of the pernicious effects of damp air at
sea far beyond the influence of vegetable effluvia.

But it may be thought that, if warm and damp air is suf-
ficient to produce fevers, the sea between the tropics would be
found more unhealthy than the land, which is known to be
contrary to experience. ‘To this it may be replied that the
ordinary cool current of air that flows from the poles to the
equator is in general sufficiently dry even over the sea to pre-
vent that part from being very unhealthy, or at least as much
so as the hot and moist valleys between the tropics. Captain
Basil Hall in his fragments of voyages says: “* As we ap-
proached the equator the thermometer fell from 82° in the
day to 79° or 80° at night. The symptoms of change of cli-
mate became daily more manifest. Every skylight and stern-
window was fastened wide open, and every cabin scuttle
driven out that a free draught of air might sweep through the
ship. ‘The seamen and marines dined on the main deck that
the lower deck might be kept as cool and as airy as possible
against the sultry and feverish night season. We generally
exposed a dozen buckets full of sea-water on the gangway at
8 or 9 o'clock in the evening, and these being allowed to
stand till the morning, 4 or 5 o’clock, became so much cooler
than the sea by the evaporation during the night, that the
shock was unspeakably grateful.”

Here we perceive that evaporation was going on actively
on the surfaces of the water in the buckets, the dew-point
must therefore have been considerably below the tempera-
ture; yet even here we find the night season described as
sultry and feverish, though the temperature was then a few
degrees lower than it was during the day: this could arise
only from the dew-point being then a little nearer to the tem-

Mr. T. Hopkins’s Observations on Malaria. 117

perature. But still the dew-point in Captain Hall’s ship
must evidently have been much below what it was in the Car-
narvon. ‘The above account of Captain Hall furnishes an
instance of what has been already stated in a general form,
that the heat of the sun rarefies the air, and makes it flow
over high in the atmosphere, before it becomes fully saturated
with vapour. ‘The most important exceptions to this general
law are to be found in those places where malaria most
abounds, that is in heated valleys or marshes near to, or within
the tropics. The sea at its surface, between the tropics, is
seldom found much hotter than 80°; but we have seen that in
African valleys the temperature has been from 100° to 118°,
and it follows that the latter places are likely to have a much
higher dew-point than the former. In some of the African:
rivers, commanders on losing many of their men and having
others ill of fever, have put out to sea in order to get out of
reach of the poisonous influence; this however it is clear, from
what has been said, may have been only a case where an at-
mosphere of, say 100°, highly charged with steam, was ex-
changed for one of 80°, with a dew-point of perhaps only 70°
or 65°. The superabundance of steam from heated valleys
or flat coasts may however, it is obvious, be taken far out to
sea by gentle winds, and thus parts over the sea may be
made as unhealthy as hot and damp valleys. This may have
been the case with the Carnarvon on board of which were the
Landers. But so little attention has been paid to hygrometry
by navigators, as to leave us in ignorance of what the dew-
points really were.

There seems good reason to believe that a warm and moist
air may be rendered more healthful by heating it, because
then the temperature would be so much higher than the dew-
point as to render it a drying air. But it is still more certain
that a reduction of the dew-point much below the temperature
removes the cause of malaria fevers: ‘The Harmattan,” says
Lander, “ a land wind, passes over the sands of Africa, and
while it lasts the dryness of the atmosphere produces an un-
pleasant feeling, but it is said to be not injurious to health.”
And again, “The effects of the Harmattan after the rainy
season are most beneficial in drying up the vapours with
which the atmosphere is loaded; and it has been observed,
that on the return of this wind at the end of the rainy season,
the recovery of invalids commences.” But this dry wind
seldom continues longer than three or four days. What the
state of the dew-point is while it lasts I have never learned,
but it must be very low compared with the temperature, as
it dries the country with extraordinary rapidity.

118 Mr. T. Hopkins’s Observations on Malaria.

That malaria fever is an effect of an excess of steam in the
atmosphere, more especially when the temperature is not con-
siderably above the dew-point, may be inferred from various
observed circumstances. In the neighbourhood of Rome, as
soonas the morningsun hasraised the temperature, danger from
malaria is much reduced. On the 10th of August the stub-
ble and weeds of the Campagna are begun to be burnt, and it
is found that whenever the heat from these fires raises the
temperature, the air is for the time partially purified ; doubt-
less because this heat, like that of the sun in the morning, dries
the air as well as heats it; that is, raises the temperature to a
greater height above the dew-point. It is a common remark
in the Campagna, that keeping up a fire in a house during
the night purifies the air; and it is well known that in those
parts of Rome where the poor people are crowded together
there is no malaria, while the thinly inhabited parts are af-
fected. In order to avoid malaria, the wealthy Italians are
careful not to sleep on a ground floor. And any one who
has observed the way in which a fog rising from a neighbour-
ing marsh or lake creeps along and spreads itself over the
lower levels, even when the air appears to be still, will see
why rooms of ground floors should be filled with damp air in
certain places. The ancient inhabitants of Italy, as may be
seen at Pompeii, built their houses round an interior square,
the entrance to which could be easily closed; this enabled
them effectually to keep out a low stratum of damp air. The
streams of fog creeping along the ground as they do, enable
us to account also for the local attacks of malaria. A slight
current of air confined or turned by a valley, a ridge, a wall,
or even a hedge, may take the vapour to a particular part,
while other parts, at a small distance, may not be visited by
it. The supply being continued from the source, the vapour
may be sufficiently dense in certain parts to make those parts
unhealthy ; but when it expands and by its elastic force diffuses
itself, it becomes too thin to saturate the adjoining air up to an
unhealthy degree. The same kind of observation will apply to
planting woods, or even hedges in particular situations ; they
may by arresting or turning the sluggish currents of saturated
air become barriers. It is said that malaria is never found
more than 2500 feet above the level of the sea; this may arise
either from the lowness of the dew-point, or the absence of
that density of steam which exists only in the lower regions
of the atmosphere.

The difference observable between the natives of a warm
and damp country, and strangers coming to it from a colder
climate, in their respective capabilities of resisting malaria is

Mr. T. Hopkins’s Observations on Malaria. 119

striking, but explicable on the supposition that obstruction of
the ordinary amount of evaporation is the evil experienced.
By the natives, the moisture which cannot find its way out of
the body by evaporation, may be thrown off by exudation,
while the temperature of the body may be kept down by suit-
able regimen. But a stranger coming from a cold and dry
climate, accustomed to take considerable quantities of heating
food into his stomach, and to have much caloric carried off
by evaporation, has a sudden stop put to this most important
process ; the water and fire remain in the system, and fever is
the result. Nature deranged in her operations struggles with
these new circumstances. ‘The stomach refuses food, because
to take it would be heaping new fuel on the body already
overcharged with fire. A copious perspiration by exudation
sometimes takes place, but mostly when the superabundant
fire has been dissipated. Inquiry may possibly show that this
is the ordinary expedient of nature under the influence of a
heated atmosphere charged with an excess of steam. Per-
haps as evaporation is checked exudation increases, and with
suitable regimen, the system may in time become adapted to
the climate. It is observed that the natives of such climates
appear to have a clammy moisture on their skins, and their
complexions are sallow. ‘The black race are the least affected
by a hot and damp atmosphere; does exudation with them
supply the place of evaporation in a greater degree than
among the European races ?

If the foregoing observations be well founded, it may be
presumed that in those parts of the world which have a high
temperature malaria will be found, and especially when the
air has been some time stagnant, in the following situations,
viz.

1. Over the open sea. It will be mild here because the

temperature is not very high.

2. Over slowly moving rivers. They will be somewhat
more heated by the sun than the sea is, and will
therefore evaporate more freely.

3. Over meadows and woods. ‘The great extent of moist
surfaces admits of great evaporation from these.

4. Over shallow stagnant water. The temperature of the wa-
ter will be high, and evaporation consequently great.

5. Over tide sands and muds. These become very hot, and
consequently evaporate copiously.

6. Over marshes. These combine great heat, extensive
surface for evaporation, and abundant moisture.

With due attention to local influences I would then propose,
in order to ascertain whether malaria be or be not the effect

120 Mr. T. Hopkins’s Observations on Malaria.

of an excess of steam in the atmosphere, to have registers
kept of the thermometrical, hygrometrical, and barometrical
states of the air wherever malaria as found to prevail. It
would be also more satisfactory if the force and direction of the
wind were noted. Such registers may possibly exist at present,
but so little attention has been paid to hygrometry, as to make
it unlikely that any should be found that would be satisfactory
in the detail. The object of the greatest importance is to ascer-
tain the dew-point, that being the point at which evaporation
ceases from substances of equal temperature, and from this
to any higher temperature is to be deduced the energy of
evaporation. Possessed of registers of this description, it
would be possible to exhibit scales of the drying powers of
the air at all temperatures that are found most conducive to
health. Physicians might then be enabled to direct patients
to remove to a more moist, or to a dryer atmosphere, as par-
ticular cases might require. New modes of prevention and
cure might also be devised, such as exposing the patients to
strong currents of air, drying the air by heating it, or even
by taking the steam out of it by exposure to hot salt, lime,
&e. &c. Exudation in a steam or hot air bath might be tried
as a succedaneum to evaporation. ‘These are however only
speculations, and facts are the things wanted. The object of
‘the writer of this paper has been to invite attention to the
subject, in order to obtain the facts requisite to the formation
of a more conclusive opinion.

Mean monthly Hygrometrical Return for the year 1832, in the
Island of St. Vincent, as given in the Official Report.

Feb.

Jan.

68:68

Mar. ‘April. May. | June.

_— |

67-14,67-99 67-93169-30 69-25

July.} Aug. |Sept. | Oct. | Nov. | Dec.

70:25 69:66 69-69) 69-39 69-41|67-31

|
| |

A Table of the Deaths per 1000 of Strength, and the portion of
those who died of Fever, per Annum, of the White Troops
in the West Indies, being the average of the returns for the
Twenty Years from 1817 to 1836, arranged in the order of
the Mortality. Taken from the Official Report from Tiwenty-

Zzwo Stations.

Deaths in Deaths by
1000, Fever.

—

1. | The Bahamas .........eeccevees 200
9. | Savannah la Mar ....ccccvess 200
3. Montego Bay eoowseocresceoreee 178—9 150—7

Prof. Forbes on the Colour of Steam. 121

Deaths ian Deaths by
1000. ever.

4, | Spanish Town......eeeeeeeee | 162—4 | 141—1
5. | Tobago cssccseceeseeeeeeeeseees 152—8 | 104—1
6. | Port Antonio .....scsceccseeeee | 149-—3 | 126—-0
7. | Up Park Camp «..ecceeeeeee | 140—6 | 120—8
g..| Dominica...... Sentaces rere ee ype fea 49-3
Dye lie MeatGick cso of. aevins tees taa's soeeet| 4 1222-8 63—1
10. | Port Royal .........+0 aaeesieeey PLES 1, | 9S-—9
EN TI GAG 6 dc stievea ven cmaciesdvensin| | LOGS 61—6
Bele PAL MOULD ovine cde cae win sueuap's0e)|! LOD-—G 80—0
13. | Stony Hill cccccosssesseeseeseee | 9O—2 | 70—5
Me British, Giuiaha’ , «sesaas cna ees 84—0 59—2
15

16

17

18

19.

20

21

.
—

GEG saactvessehanes skeet dawaavs 84—9 63—2
Fort Augusta seeescesseeeeeeees
St. Kits, Nevis and Tortola 71—0 |} 42—1
CSCC Ae. be siede> cea euiontions Gie=s 26—3
Barhadoesiuccetawedesticetiqecess 58—5 11—8
SAVIN Cems eedace cess temececioes 54—9 i
Antigua and Montserrat...... 40—6 14—9
29,.| Maroon Town | csccoecccecsecs 39—7 15—3

The most sickly as weli as the most fatal period of the year
extends from August to December, and during this time the
winds are generally from the south and west. The least un-
healthy months are March, April, and May, when the trade-
wind blows from the east. The annual mortality of the troops
in England has for a long series of years been only fifteen
to the thousand.

XXI. On the Colour of Steam under certain circumstances.
By Professor Forses*.
1 the end of May or beginning of June last, I happened to
stand near a locomotive engine on the Greenwich railway,
which was discharging a vast quantity of high pressure steam
by its safety valve. I chanced to look at the sun through
the ascending column of vapour, .and was struck by seeing
it of a very deep orange red colour, exactly similar to dense
smoke, or to the colour imparted to the sun when viewed
through a common smoked glass.
I did not pay much attention to the fact at the moment, nor
did I attempt to vary the experiment; but reflecting on it af-

* Communicated by the Author.

122 Professor Forbes on the Colour of

terwards it seemed to me not only as in itself very singular,
but as still more extraordinary that I should never have heard
of a property of steam which must have been witnessed by
thousands of persons. Some months after (in the end of Oc-
tober), being on the Newcastle and Carlisle railway, I resolved
to verify the fact, which I had no difficulty in doing, and
I further discovered a very important modification of it. For
some feet or yards from the safety valve at which the steam
blows, its colour for transmitted light is the deep orange red
I have described*. At agreater distance, however, the steam
being more fully condensed, the effect entirely ceases: even
at moderate thicknesses the steam cloud is absolutely opake
to the direct solar rays, the shadow it throws being as black
as that of a dense body ; and when the thickness is very small
it is translucent, but absolutely colourless, just like thin clouds
passing over the sun, which have indeed a perfect analogy of
structure. When the steam is in this state no indication of
colour is perceptible in passing from the thickness correspond-
ing to translucency to that which is absolutely opake.

Having made these observations, which were all that the
circumstances enabled me to accomplish, I was very anxious to
verify them with steam of various pressures, and to determine
the following amongst other points: (1) whether steam in its
purely gaseous form is really, as commonly supposed, colour-
less; (2) whether the colour depends ona stage in the process
of condensation, and on that alone; (3) what effect the tension
of the steam has upon the phenomena.

But there was another inquiry which interested me much
more than all these, which was to examine how the spectrum
was affected by the absorbent action of the steam, which left
the red and orange rays predominant. Judging from the phe-
nomena of absorption of light by gaseous bodies, and especi-
ally the singular action of nitrous acid gas in dividing the spec-
trum into a vast number of bands, discovered by Sir D.
Brewster, I thought it by no means improbable that steam
acting in a similar manner might exercise its specific action
upon the prismatic colours at many points. Should this con-
jecture be confirmed, I also foresaw an application to the phe-
nomena of the atmosphere and the production of the atmo-
spheric lines of the solar spectrum also remarked by Sir D.
Brewster.

After various ineffectual attempts to obtain the requisite fa-

* The same may be observed daring the ordinary progress of the engine
in the steam thrown into the chimney, but the presence of smoke renders
the experiment less satisfactory.

Steam under certain circumstances. 123

cilities, Mr. Edington of the Phoenix iron-works at Glasgow
most kindly put at my disposition an excellent high-pressure
boiler, and further afforded me every facility for prosecuting
my experiments on the optical properties of steam. I first ex-
amined the simple phenomena of colour as seen by the naked
eye. A lantern* was held behind a jet of steam issuing from
a stopcock in the top of the boiler, having a bore of + inch.
When the safety valve (which acted with great promptness)
was loaded with 50 pounds on the inch, the steam issued
nearly invisible, and at the small thickness of the jet in that
part perfectly colourless. As the light was raised the orange
colour appeared at the height of a few inches above the cock,
and rapidly deepened up to a height of about 26 inches, after
which it appeared that the rapid condensation of the steam
only rendered it more opake without deepening its hue. At
that point therefore I resolved to transmit the light and to
analyse by a prism. A theodolite and good prism in front of
the telescope were placed at the distance of about 25 feet from
the boiler; beyond the steam-cock a lantern with a lens for pa-
rallel rays was adjusted, and between the steam-cock and the
prism a slit of variable width. The light reaching the prism
through the slit must first pass through the column of steam
at a height of about 20 inches from the orifice. To test the ad-
justment of the apparatus, and also for the purpose of con-
trast, I had provided a bottle, about 5 inches in diameter, full
of remarkably dense nitrous acid gas, which Mr. Kemp was
so good as to prepare for me. When this was placed where
. the steam was to issue, the appearance of the nitrous acid spec-
trum was magnificently displayed. I then removed the bottle
and opened the steam-cock gradually (the pressure on the
safety-valve being 55 pounds above the atmosphere, or the
tension of the steam 4% atmospheres), the violet end of the
spectrum was almost instantly absorbed, then the whole blue
and part of the green, just as in the nitrous acid spectrum, but
no lines were visible in the remaining part. When the cock was
fully opened the spectrum exhibited a singular appearance ;
the bright red was the only part which seemed natural. The
extreme red was slightly invaded by the opacity of the steam.
Most of the orange, the yellow, and as much of the green as
was not absorbed had a dirty disagreeable hue, which I de-
scribed in a memorandum at the time as “ dingy, alterna-
ting between yellow and purple, with shades of green;
when the steam had its highest pressure there was a deci-
dediy purple tinge.’ The appearance to the naked eye
of the slit was now identically the colour of the nitrous acid
* The experiments were performed at night.

124 Professor Forbes on the Colour of

gas, through which I from time to time viewed a distant gas
‘ flame, and compared it with the colour of the slit. The ex-
periment was performed under 50 and 55 pounds many times
over. The light examined was then caused to pass through
the steam only 10 inches from the orifice of the stop-cock,
under the idea that though the colour there was fainter, pos-
sibly there might be a tendency to develope lines in the spec-
trum. But the experiment being made under the same pressure
as before, the effect was similar, only much less intense: the
slit had now but a faint tawny colour, and prismatic analysis
showed the violet alone absorbed.

Steam blowing off at 25 pounds, the lantern and slit 20
inches above the orifice as at first. ‘To the eye the light ap-
peared as red as under 55 pounds. Mr. Edington observed
that the colour was deeper than that of the nitrous acid gas
bottle. Neither he nor his assistant ever observed the colour
of steam before. Prismatic phenomena as before; only the
obscuration not quite so great.

Steam blowing off at 15 pounds.“ Evidently redder than
the gas bottle: same phenomena of spectrum, but green re-
mains pure throughout, and verges on (bounds immediately
with) orange. During the absorption of violet before vanish-
ing (the steam-cock being gradually opened) it assumes a dirty
white colour, verging on yellow and purple.” A common
lamp was viewed through different parts of the column of
steam of this pressure, from the orifice up to a height of 5 or
6 feet, and wherever it was not entirely obscured, it appeared

of different shades of smoke colour up to an intense tawny |

orange.

With 7 pounds on the inch. Still visibly red to the eye;
prismatic phenomena similar but slighter.

With 4 pounds, no longer visibly red to the eye when ar-
ranged as above; and seen with the prism the violet appears
but little affected. When let off in large quantity from the
safety-valve, and a lamp viewed through it, there is a faint
redness close to the orifice, but everywhere above, the transi-
tion is from colourless translucency to complete opacity. At
about 2 and 1 pound no colour can be detected.

From these experiments I deduce the following conclu-
sions :

(1.) Steam in its purely gaseous form is, as commonly sup-
posed, colourless, at least at small thicknesses.

(2.) The orange red colour of steam by transmitted light
appears to be due toa particular stage of the condensing pro-
cess. Before condensation, steam is colourless and transpa-
rent; it is next transparent and smoke-coloured ; finally it

Steam under certain circumstances. 125

becomes colourless at small thicknesses, and absolutely opake
at greater.

(3.) The state of tension of the steam seems only to affect
the phenomena so far as it renders the critical colorific stage
of condensation more or less completely observable.

(4.) The absorptive action of steam on the spectrum is not
exerted in the same way as that of other gaseous coloured
bodies, such as nitrous acid gas, and iodine vapour. It cuts
off, however, totally the same part of the spectrum as nitrous
acid does. Its phenomena perhaps have a greater analogy
to those of opalescence than any other.

The effect of mere change of mechanical structure in alter-
ing the optical properties of bodies is a phenomenon likely to
give important information, .both as to the constitution of
matter and the constitution of light; and the present observa-
tions may perhaps be one day viewed as a contribution to~
wards a mechanical theory of vapour, including that most sin-
gular stage which intervenes between the gaseous and com-
pletely liquid form, and which is probably connected with the
mechanical suspension of clouds. It is at all events very im-
portant to know that a portion of watery vapour confined in
a close vessel, and subjected to change of temperature alone,
without chemical change, is capable of undergoing the altera-
tions of colour and transparency which have been adverted to.
The singular fact noticed by Sir D. Brewster in the case of
nitrous acid gas, the colour of which deepens to an intense
orange red by the simple application of heat, seems to be a
fact of this kind.

I cannot doubt that the colour of watery vapour under cer-
tain circumstances is the principal or atly cause of the red
colour observed in clouds. ‘The very fact that that colour
chiefly appears in the presence of clouds, is a sufficient refu-
tation of the only explanation of the pheenomena of sunset and
sunrise having the least plausibility, given by optical writers.
If the red light of the horizontal sky were simply complemen-
tary to the blue of a pure atmosphere, the sun oaght to set red
in the clearest weather, and then most of all; but experience
shows that a lurid sunrise or sunset is always accompanied by
clouds, or diffused vapours, and in a great majority of cases
occurs when the changing state of previously transparent and
colourless vapour may be inferred from the succeeding rain.
In like manner terrestrial lights seen at a distance grow red
and dim when the atmosphere is filled with vapour soon to
be precipitated. Analogy applied to the preceding observa-
tions would certainly conduct to a solution of such appear-
ances; for I have remarked that the existence of yapour of

126 Euclid’s Elements: Electrical Excitation

high tension is by no means essential to the production of
colour, though of course a proportionally greater thickness
of the medium must be employed to produce a similar effect
when the elasticity is small.

Glasgow, Dec. 29, 1838.

XXII. Remarks on a paper in the Philosophical Magazine
Sor December 1838, on a certain demonstration of Euclid.
By A CorresponvEnt.

To the Editors of the Philosophical Magazine and Journal.

GENTLEMEN,

N this month’s number of the Philosophical Magazine (Dec.

1838. vol. xiii. p. 434) one of your correspondents has given

a method of dispensing with the 12th axiom of the 1st book

of Kuclid’s Elements, apparently not being aware that Pro-

fessor Peacock has given the same in his treatise on algebra.

It would, indeed, be immediately suggested by a perusal of

the demonstration of the 12th axiom, and the remarks upon

it by Ptolemy, quoted by Proclus in his commentary on
Euclid’s Elements.

It appears to me to be open to the objection which Proclus
makes to the emendations of Aineas Hierapolites, and others on
the Elements, ‘for the geometrician appears to have chosen
such hypotheses as either abound in affirmation or are more
simple.” Setting aside other more weighty objections, Pro-
fessor Peacock’s proposed amendment, although it removes
one difficulty, is certainly not sufficiently simple to be placed
among the definitions of the 1st book. When I say not suf-
ficiently simple, I mean that it does not immediately impress
upon one’s mind the common idea of the subject defined, an
object to which Euclid has always been careful to adhere.

Your obedient Servant,
Jesus College, Cambridge, Dec. Ist, 1238. J, OQ.

XXIII. Notice of the Electrical Excitation of a Leather Strap
connecting the Drums of a Worsted Mill ; in aletter to Dr.
Faraday from the Rev. T. Drury*.

My Dear Sir,
PERMIT me to describe an extraordinary electrifying ma-
chine which I yesterday witnessed, and which I think
will be new even to you.

* Communicated by Dr, Faraday.

of a Leather Strap: Voltaic Series. 127

It is no other than a leather strap, which connects two
drums in a large worsted mill in the town of Keighley.

The dimensions and particulars of the strap are as follows:
HE 18141 ABET (tle 100-0) stills iain poe teat
Preamthi:6 ye cwsiseieli. io) “Velev to Ganches
ibieletseas ‘SiG. acs! 4) lidnalglese te «tt do:

It makes 100 revolutions in a minute.

The drums, over which it passes at both ends, are two feet
in diameter, made of wood fastened to iron hoops and turning
on iron axles; these drums are placed at 10 feet distance from
each other, and the strap crosses in the middle between the
drums, where there is some friction; the strap forming a figure
of eight. There is no metal in connexion with the strap, but
it is oiled. If you present your knuckle to the strap above the
point of crossing, brushes of electrical light are given off in
abundance, and when the points of a prime conductor are held
near the strap, most pungent sparks are given off to a knuckle
at about two inches ; I charged a Leyden jar of considerable
size in a few seconds by presenting it to the prime conductor.
The gentleman who told me of this curious strap has frequent-
ly charged his electrical battery in a very short time from it,
and he informed me that it is always the same, generating
electricity from morning to night without any abatement or
alteration. If this strap had the advantage of silk flaps and a
little amalgam, it would rival the machine in the lecture room
in Albemarle-street.

Pray excuse the earnestness of

Your most faithful Servant,

Keighley Rectcry, Yorkshire, THEODORE Drury.
Dec. 17, 1838.

XXIV. On Voltaic Series and the Combination of Gases by
Platinum. By W. Rh. Grove, Esq. M.A.

GENTLEMEN, Swansea, Dec. 14, 1838.

N a letter on an economical constant battery which you

did me the honour to publish in your number for the present
month, (Dec. 1838. vol. xiii. p. 430) I ventured to suggest the
more extensive employment of the porous septum as an instru-
ment of analysis for voltaic combinations. I am not unaware
of the experiments of De la Rive, Porret, &c., and meant to
allude less to its use in the decomposing cell, than in the trough
itself, and to its practical application to the improvement of ap-
paratus. ‘Ihe following experiments instituted with this view
may not be uninteresting to your readers; they differ, it will

128 Mr. Grove on Voltaic Series and the

be seen, materially from those of Sir H. Davy on unimetal ©
series. Having constructed two troughs in the manner
described in my last letter, one of alternate plates of iron
and unglazed porcelain, the other of plates of copper and
porcelain, I poured into the alternate cells of the first a
saturated solution of sulphate. of iron and dilute sulphuric
acid. With this arrangement, as was to have been expected,
little electric action was manifest; equally trifling were the
effects when sulphate of iron and dilute muriatic acid were
the electrolytes; when however nitric acid was employed
with sulphate of iron a tolerably active current was gene-
rated: with twelve plates acidulated water was decomposed
and a slight shock felt in the moistened hands. I now tried
the copper trough with sulphate of copper and the same
three acids respectively: with the sulphuric and nitric the
electric development was but slight; but with the muriatic,
diluted with about twice its quantity of water, a most energetic
series was formed. With twelve plates acidulated water was
rapidly decomposed *: with a pair of copper plates each ex-
posing about 36 square inches of surface, a Ritchie’s rotating
magnet was whirled rapidly round, exhibiting small but
brilliant sparks; its revolution continued for several hours
without the addition of fresh acid; in fact the energy was
fully equal to that displayed by similarly sized arrangements
of zinc and copper, excited by muriatic acid but without dia-
phragm: a strong solution of common salt, substituted for
muriatic acid, produced effects not far inferior, On ex-
amining the batteries when exhausted, I found the sides of the
copper which had been exposed to the sulphate of copper
covered with a fine coating of that metal ; the affinity between
the chlorine and the copper had consequently (according to
the principle of preponderating affinity established by Dr.
Faraday,) been sufficiently powerful to cause the solution of
copper to be de-oxidated by the transferred hydrogen and to
produce vigorous electro-motive action without the presence
of a dissimilar metal.

It would appear from this that the diaphragm is of more
practical importance in voltaic combinations than as a mere

* It ismore expensive but much more satisfactory, if,in these experiments,
series, as in the text, be employed instead of single combinations. I have
frequently imagined I had obtained results from a single pair with the gal-
vanometer, but have found them entirely negatived when the same combi-
nation was used in series. This was most probably owing to the many in-
terfering circumstances to which the magnetic galvanoscope is liable, or
perhaps to superficial differences in the two plates of metal.

Combination of Gases by Platinum. 129

preventer of cross precipitation ; for instance, if zinc and copper
be employed with muriatic acid but without diaphragm, putting
out of the question the precipitation of the zinc on the copper,
the power would be only as the excess of the affinity of chlorine
for zinc over its affinity for copper; with the diaphragm we
have no opposing current, the affinity of chlorine for copper,
assisted by that of hydrogen for oxygen, is able readily to
cause decomposition of the sulphate of copper and give rise
toa strong current. In the first or common arrangement,
this current opposes, and consequently, in estimating the re-
sulting power, must be deducted from that produced by the
superior affinity of chlorine for zinc; in the last arrangement,
the thus evidently inferior obstacle, the resistance to decom-
position of the sulphate, is the only one to be overcome*.

It would seem then that the best form of combination would
be one with two metals and two electrolytes, the generating
metal being one which has the strongest affinity for the anion
of the electrolyte in contact with it, while the other solution is
most readily decomposable by its cation and does not cause a
precipitate upon which its own anion would readily react ; zinc
with muriatic acid and copper with sulphate of copper fulfil
these conditions to a great degree; if these principles be
correct, very superior combinations may be discovered. I
cannot refrain from expressing, with much diffidence, a hope
that these experiments may be thought worthy of verification
and extension by those “ older in practice, abler than myself.”

I remain, Gentlemen, yours, &c.,

W. R. Grove.

P.S. Jan.1839. I should have pursued these experiments fur-
ther, and with other metals, but was led aside by some experi-
ments with different solutions separated by a diaphragm and
connected by platinum plates; in many of these I have been
anticipated.

I will however mention one which goes a step further than
any hitherto recorded ; and affords, I think, an important il-
lustration of the combination of gases by platinum.

Two strips of platinum 2 inches long and three-eighths of
an inch wide, standing erect at a short distance from each

* The reason why iron with sulphate of iron and muriatic acid is inferior
to the copper combination here described, may be that the difference of
affinities is not so great, but more probably proceeds from the minute cur-
rents on the surface of the iron weakening the efficacy of the chemical
action to produce a general current; copper being more homogeneous
evolves no hydrogen and the whole action is utilized. Copper with sul-
phuret of potassium and sulphate of copper is a most powerful unimetal
combination, if unimetal it may be called.

Phil. Mag. S. 3. Vol. 14. No. 86, Feb. 1839. K

130 Mr. Grove on the Combination of Gases by Platinum.

other, passed, hermetically sealed, through the bottom of a
bell glass; the projecting ends were made to communicate
with a delicate galvanometer; the glass was filled with water
acidulated with sulphuric acid, and both the platina strips
made the positive electrodes of a voltaic battery until per-
fectly clean, &c.; contact with the battery having been
broken, over each piece of platinum was inverted a tube of
gas, four-tenths of an inch in diameter, one of oxygen, the
other of hydrogen, acidulated water reaching a certain mark
on the glass, so that about half of the platina was exposed to
the gas, and half to the water. The instant the tubes were
lowered so as to expose part of the surfaces of platinum to
the gases, the galvanometer needle was deflected so strongly as
to turn more than half round: it remained stationary at 15°,
the platinum in the hydrogen being similar to the zinc element
of the pile. When the tubes were raised so as to cover the
plates with water, the needle returned slowly to zero; but the
instant that the tubes were lowered again, it was again deflect-
ed; if the tubes were changed with regard to the platina, the
deflection was to the contrary side.

The action lowered considerably after the first few minutes,
but was in some degree restored every time the tubes were
raised so as to wash the surface of the platina, and again low-
ered. After 24 hours, the water had risen half an inch in the
tube containing hydrogen, and three eighths of an inch in that
containing oxygen. In two other tubes, without platina, but
with the same gases and immersed in acidulated water for the
same time, the water had scarcely perceptibly risen, the effect
therefore could not have been due to solution; the same sheets
of platinum were exposed to atmospheres of common air and
of similar gases, i. e. both to oxygen or both to hydrogen, &c.,
but without affecting the galvanometer. The platinum in the
hydrogen was made the positive, and that in the oxygen the
negative electrode of a single voltaic pair; the water now rose
at the rate of three-eighths of an inch per hour in the hydrogen
tube and proportionally in the oxygen; when the platina was
not assisted by a pair of metals the oxygen was absorbed in
more than its relative proportion. I hope, by repeating this
experiment in series, to effect decomposition of water by
means of its composition.

\PriMSloy]
XXV. Proceedings of Learned Societies.

ROYAL SOCIETY.

Anniversary Meeting, Nov. 30, 1838 (continued).—The following
Report of the Council respecting the awards they have made of two
Copley Medals, two Royal Medals, and one Rumford Medal, was
read.

The Council have awarded a Copley Medal to Professor Gauss,
for his researches and mathematical researches on Magnetism.

Professor Gauss’s labours on the subject of magnetism, published
at various periods, and continued with increasing activity up to the
present time, have given to our knowledge of that subject very va-
luable and striking additions. In his dissertation entitled, “ Inten-
sitas vis magnetic terrestris ad mensuram absolutam revocata*,”
(Géttingen, 1833,) he showed how, by a skilful combination of ex-
periment with mathematical calculation, several of the most difficult
problems belonging to the subject may be solved; namely, the de-
termination of the magnetic axis of a needle; the exact determination
of the moment of inertia of an oscillating needle ; the deviation pro-
duced in the direction of the horizontal needle by the neighbour-
hood of a magnet; and the determination of the absolute intensity
of the horizontal magnetic force of the earth. A combination of
magnetic observers in different places had been set on foot by M.
yon Humboldt in 1828 ; a magnetic observatory was erected at Got-
tingen in 1833 ; and in consequence of these circumstances the cu-
rious discovery was made in 1834, that the minute momentary
changes in the position of the horizontal needle are simultaneous
and corresponding at distant places. This led M. Gauss to direct
the attention of men of science more particularly to this subject ;
and the operations of the “ Magnetic Union” of observers were car-
ried on with great activity under his guidance, The “ Results of
the observations of the Magnetic Union” for 1836 and for 1837,
published by MM. Gauss and W, Weber, contain an account of the
consequences of these exertions. They also contain descriptions of
instruments inyented by M. Gauss for the purpose of these obser-
vations, namely, the magnetometer, and other magnetical apparatus
of his construction, which has already been sent to the observatories
of Bonn, Dublin, Freiberg, Greenwich, Kasan, Milan, Munich, Na-
ples, Upsala, Krakow, Leipzig, and Marpurg. Also the Bijfilar
Magnetometer, which determines directly the variation of horizontal
intensity. The “Results” further contain various mathematical
calculations of great importance, on the subject of the above instru-
ments, and of the observations made by them. And it appears by
observations made in March, 1838, at Gottingen and three other
places, with the Bifilar apparatus, that there is the same correspond-

* An abstract of Prof. Gauss’s dissertation was given in Lond. and Edinb,
Phil. Mag., vol. ii. p. 291; and a translation of the “ Results” published
by him and Weber, also mentioned in the above report of the Council, is
preparing for immediate publication in the Fifth Number of the Screnziric

emoins.—Ebit.

K 2

132 Royal Society.

ence in the simultaneous changes of intensity at different places
which had already been discovered in the declination. The inge-
nuity shown in the invention of instruments and processes, the ma-
thematical skill employed in treating the observations, and the im-
portance and interest of the results, are well deserving of being ho-
nourably marked by the Royal Society, and the adjudication of the
Copley Medal to M. Gauss.

The Council have also awarded a Copley Medal to Dr. Faraday
for his discovery of Specific Electrical Induction, published in the
eleventh series of his Experimental Researches in Electricity*.

From the peculiar view which he had taken of the phenomena
of induction, Dr. Faraday was led to expect some particular relation
of this process to different kinds of matter, through which it might
be exerted. This relation he succeeded in establishing by the most
decisive experiments.

The phenomena are shown in their simplest form by an instru-
ment which he has named a Differential Inductometer. It consists
of three insulated metallic plates, placed facing each other; the cen-
tre one being fixed, and the other two moveable upon slides, by
which they may be approximated to or withdrawn from the centre.
Each end plate is connected with an insulated leaf of an electro-
meter. When a charge is communicated to the centre plate under
ordinary circumstances, the induction is equal on both sides, and
the gold leaves are not disturbed. But if after uninsulating them,
and again insulating them, a thick plate of shell-lac or sulphur be
interposed between two of the plates, unequal induction will take
place on the two sides, and the gold leaves will attract one another.
By these means Dr. Faraday ascertained that, taking the specific
inductive capacity of airtobe. . . . .. It

Diab Of Aolasedis tt oe aoe a ene
Potente Pers ie tat ae
Salphar’ 5.04 Wer ynshien ss ees

The results obtained with spermaceti, oil of turpentine, and naph-
tha were higher than that of air, but their conducting powers inter-
fered with the accuracy of the experiments.

By another form of apparatus he ascertained that all aériform
matter has the same power of sustaining induction; and that no
variations in the density or elasticity of gases produced any varia-
tion in their electric tension until rarefaction is pushed so far as that
discharge may take place across them.

Hot and cold air were compared together, and damp and dry air,
but no difference was found in the results.

The great importance of the discovery and complete establishment
of such a principle as that of specific inductive capacity, in all its
relations both experimental and theoretic, is so palpable, that any
comment must be superfluous ; and the Council have felt they can-

* Dr. Faraday’s Eleventh Series of Researches will be found in our last
coors p. 281, et seg., and the Supplement to it in the preceding Number,
p. 34,

ee Se

Royal Society. 133

not better mark their sense of the value of this discovery than by
awarding the Copley Medal to its author.

The Council have awarded the Royal Medal for Mathematics to
H. F. Talbot, Esq., for his two memoirs entitled, “ Researches in the
Integral Calculus,” published in the Philosophical Transactions for
1836 and 1837*.

Nothing perhaps tends more directly to bring the correctness of
refined theoretical investigations in physics to the test of numerical
results, than improvements in and extensions of the processes of
integration. Any advance therefore which is made in this difficult
branch of analysis must be viewed not merely in the light of a diffi-
culty overcome in the progress of abstract science, but likewise as ha-
ving an important bearing on the advancement of physical inquiry.

The branch of analysis to which Mr. Talbot’s researches belong
is one which is connected with along series of valuable investiga-
tions from the time of Fagnani and Euler to that of Legendre, Jacobi,
and Abel: it relates to integrals under the same form which are
separately nonscendental, but which furnish, under particular con-
ditions of the variables, an algebraical result when two or more of
them are connected together with the signs + or—. The celebrated
theorem of Abel}, which may be made to comprehend some of Mr.
Talbot's results, is the most comprehensive and most important of
all the general conclusions which have been arrived at in this de-
partment of analysis: but the process adopted by Mr. Talbot is more
allied to that followed by Fagnani than by Abel, and is equally re-
markable for its great simplicity and for the vast number of novel
and interesting results which it furnishes, including not merely several
of the most remarkable of those which are already known, but like-
wise many others which are apparently not deducible by other
methods.

The Council have awarded the Royal Medal for Chemistry to
Professor Thomas Graham for his paper entitled “ Inquiries respect-
ing the Constitution of Salts; of Oxalates, Nitrates, Phosphates,
Sulphates, and Chlorides,” which was read to the Society on the 24th
of November 1836}, and since published in the Philosophical Trans-
actions. This paper they have considered as being the last of a
series on a general subject of great importance: and as the sequel
of Professor Graham’s researches on the Arseniates, Phosphates, and
modifications of Phosphoric Acid, read to the Society on the 19th
of June 1833, and published in the Philosophical Transactions of
the same year}. He has therein shown that, by considering the
water which enters into the composition of the different classes of
salts, which the phosphoric acid forms with the several bases, and
which has been considered as water of crystallization as standing in
a basic relation to the acid, a very simple view might be taken of

* Abstracts of Mr. Talbot’s papers appeared in Lond. and Edinb. Phil,
Mag,, vol. viii. p. 549, and vol. x1. p. 210.—Enir.

+ See Lond. and Edinb. Phil, Mag., vol. vi. p. 116.—Eprr.

{ An abstract of Prof. Graham’s papers appeared in Lond. and Edinb,
Phil. Mag., yol. iii. p. 451, 459, and vol. x. p. 216,—Eprr,

134 Royal Society.

this very complicated subject. According to this theory, there are
three sets of phosphates, in which the oxygen of the acid being 5,
the oxygen in the base is respectively 3, 2, or 1; the remaining
equivalents of oxygen, in the two first cases, being supplied by that
portion which exists in the 2 or 3 equivalents, respectively, of the
basic water, which water is wholly absent in the third case. These
three classes of salts Professor Graham proposes to term, respect-
ively, monobasic, bibasic, and tribasic salts. Professor Graham has
extended these views of the basic formation of water in salts to the
case of the sulphates, in a paper communicated to the Royal Soci-
ety of Edinburgh, and published in the 13th volume of their Trans-
actions, on “ Water as a constituent of Salts*.” The principal ob-
ject of this paper, however, was to show that water exists in a dif-
ferent state in certain salts, and does not exercise a true basic func-
tion, being capable of being replaced by a salt, and not by an alka-
line base, and giving rise to a class of double salts. This inquiry
was suggested by the tendency of phosphate of soda to unite with
an additional dose of soda, and form a swbsalt, which had been traced
to the existence of basic water in the former. The result was, that
in the well-known class of sulphates, consisting of sulphates of mag-
nesia, zine, iron, manganese, copper, nickel and cobalt, all of which
crystallize with either five or seven equivalents of water, one equi-
valent proved to be much more strongly united to the salt than the
other four or six. The latter, to which the name of water of cry-
stallization should be restricted, may generally be expelled by a heat
under the boiling point of water; while the remaining equivalent
uniformly requires a heat above 400° of Fahrenheit for its expule
sion, and seems to be, in a manner, essential to the salt. Thus in
the double sulphate of zine and potassa, the single equivalent of
water, existing in the sulphate of zine, is replaced by an equivalent
of sulphate of potassa, while the six equivalents of water of crystal-
lization remain; and all the other salts of this class combine with
one another in a similar manner.

The super-sulphates must also be regarded as analogous to dou-
ble salts; the bisulphate of potassa, for example, being a sulphate
of water and potassa.

There is likewise a provision in the constitution of hydriated sul-
phuric acid for the production of a double salt analogous in its con-
stitution to sulphate of zinc. Sulphuric acid, of the specific gravity
1°78, contains two equivalents of water, and is capable of erystal-
lizing at a temperature of 40° of Fahrenheit, being, in fact, the only
known crystallizable hydrate of sulphuric acid. The second equi-
valent of water, contained in the hydrated acid, is capable of being
replaced by an equivalent of sulphate of potassa, which is itself a
salt, and a bisulphate of potassa is the result of this substitution.
But the first equivalent of water can be replaced only by an alkali
or true base. Professor Graham distinguishes water in these two

* The paper here referred to will be found also in Lond. and Edinb.
Phil. Mag,, vol. vi. p. 827 e¢ seg.—Enpir.

Royal Society. 185

states of combination as basic and saline water. Thus the hydrate
of sulphuric acid, already mentioned, contains one equivalent of
basic, and one equivalent of saline water. It is, in his nomencla-
ture, a sulphate of water with saline water, as the hydrous sulphate of
zinc is a sulphate of zine with saline water. The bi-sulphate of potassa
is also a sulphate of water with sulphate of potassa, and corresponds
with the double salt of sulphate of zinc with sulphate of potassa.

The results which Professor Graham has thus obtained, and which
he has communicated, partly to the Royal Society, and partly to
the Royal Society of Edinburgh, suggested to him the probability
that the law with respect to water in the constitution of the sul-
phates would extend to any hydrated acid, and the magnesian salt
of that acid; and his researches on this extension of the subject
constitute the substance of his last communication to the Royal So-
ciety. As he had already found that the sulphate of water is con-
stituted like the sulphate of magnesia, so he now finds oxalate of
water to resemble the oxalate of magnesia, and the nitrate of water
to resemble the nitrate of magnesia. He is moreover of opinion, that
this correspondence between water and the magnesian class of ox-
ides extends beyond their character as bases, and that, in certain
subsalts of this class, the metallic oxide replaces the water of cry-
stallization of the neutral salt, and discharges a function which was
thought peculiar to water.

The same kind of displacement, which takes place in the formas
tion of a double sulphate by the substitution of a salt of the same
class for an equivalent of water, appears to occur likewise in the
constitution of double oxalates; and the application of this princi-
ple elucidates the constitution of that class of salts, as well as of the
super-oxalates, and explains the mode in which they are derived.

Lastly, the same law is traced in the constitution of the chlorides
of the magnesian class of metals, which are found to have two equi-~
valents of water strongly attached to them, and which may therefore
be considered as constitutional. Many of them have two or four
equivalents more, the proportion advancing by multiples of two
equivalents.

Professor Graham has supported these views, not only by nume-
rous arguments, but also by experimental investigations of the phy-
sical properties of different classes of salts, and a great number of
chemical analyses; and he, has thus largely added to our positive
knowledge of this somewhat neglected branch of chemical science.

The Council, without pronouncing any judgement on the ques-
tion whether Professor Graham’s hypothesis concerning the differ-
ent functions of water in the constitution of salts be a representa-
tion of the real mechanism of nature, are of opinion, that the dis-
cussion of his new and ingenious views will be highly conducive to
the progress of science, particularly in the department of organic
chemistry, in which they have been already followed out with suc-
cess by some eminent foreign chemists, and have accordingly awarded
to Professor Graham the Royal Medal for Chemistry of the present
year, for his valuable researches in this department of science.

136 _ Royal Society.

The Council have awarded the Rumford Medal to Professor
Forbes, for his discoveries and investigations of the Polarization
and Double Refraction of Heat, published in the recent volumes of
the Transactions of the Royal Society of Edinburgh*.

That solar heat, like the light which it accompanies, may be po-
larized, was shown by tlie early experiments of MM. Malus and
Berard; but the announcement of M. Berard, that heat from other
sources was also capable of polarization, not having been confirmed
in subsequent repetitions of his experiments by other philosophers,
it became of the highest importance to establish this analogy be-
tween light and heat from whatever source the latter might be
derived.

The admirable instrunent, the Thermo-multiplier, invented by
MM. Nobili and Melloni, afforded facilities for the prosecution of
inquiries of this nature, of which the inventors and others were not
tardy in availing themselves. One of the most important results
obtained by M. Melloni, and confirmed by Professor Forbes, the
refrangibility of non-lumimous heat by a prism of rock-salt, appeared
to point to the polarization and double refraction of heat as almost
necessary consequences. The experiments, however, of both these
philosophers with tourmaline, undertaken nearly at the same time,
appeared to negative the fact; but Professor Forbes becoming sen-
sible of the source of error, in the conclusions he had at first drawn
from his experiments, soon saw that his results clearly indicated the
effect he was in search of. His subsequent experiments established
the fact, that in the transmission of heat from an Argand lamp, from
incandescent platinum, and even from non-luminous heated brass,
through slices of tourmaline cut parallel to the axis of the crystal,
a portion of the heat is polarized, when the axes of the crystals are
at right angles to each other; and these results were confirmed by
M. Melloni.

But Professor Forbes did not allow the polarization of heat to
rest solely upon the results obtained with tourmaline. By employ-
ing bundles of plates of mica, and adjusting them at proper angles,
he not only obtained much more decisive results, particularly with
heat from a non-luminous source, but such results as go to esta-
blish the singular fact, that the degree of the polarization of heat is
dependent on the nature of its source. He has further shown the
depolarization of heat by the interposition of a mica plate, and its
circular polarization by means of two total internal reflections in
an interposed rhomb, or two prisms of rock-salt.

The Council consider that they cannot better testify their estima-
tion of the discoveries and experimental investigations of Professor
Forbes, than by awarding to him a Medal, bequeathed by its distin-
guished founder, as a premium to the author of discoveries tending
to improve the theories of heat and light.

* See Lond, and Edinb. Phil. Mag.. vol. vi. p, 134 et seq.; vol. xi. p. 542;
vol. xii. p. 545. The papers in which M, Melloni’s Researches are de-
tailed have been given in the first volume of the Scientific Memoirs.— -

Epir.
'

Royal Society. 137

President.—The Marquis of Northampton.— 7reasuwrer.—John
William Lubbock, Esq., M.A., V.P.—Seeretaries—Peter Mark
Roget, M.D.; Samuel Hunter Christie, Esq., M.A.—Foreign
Secretary.—William Henry Smyth, Capt. R.N.— Other Members of
the Council—H.R.H. the Duke of Sussex, K.G., V.P.; Francis
Baily, Esq., V.P.; John George Children, Esq., V.P.; John Fre-
deric Daniell, Esq.; C. G. B. Daubeny, M.D.; Thomas Galloway,
Esq., M.A.; Thomas Graham, Esq.; Sir John F. W. Herschel,
Bart., M.A., V.P.; Francis Kiernan, Esq.; George Rennie, Esq.;
John Forbes Royle, M.D., V.P.; Rev. Adam Sedgwick, M.A.;
Robert Bentley Todd, M.D.; Charles Wheatstone, Esq.; Rev.
William Whewell, M.A.; Rev. Robert Willis, M.A.

Report of a Joint Committee of Physics and Meteorology referred to,
by the Council of the Royal Society, for an opinion on the propriety
of recommending the establishment of fixed magnetic observatories,
and the equipment of a naval expedition for magnetic observations
in the Antarctic Seas, to Her Majesty’s Government, and to report
generally on the subject : together with the Resolutions adopted on
that Report, by the Council of the Royal Society.

Reporr.—Thesubject of terrestrialmagnetism has recently received
some very important accessions which have materially affected not
only the point of view in which henceforward it will be theoretically
contemplated, but also the modes of observation which will require to
be adopted for completing our knowledge of the actual state of the
magnetic phenomena, and furnishing accurate data for the construc-
tion and verification of theoretical systems. It was for a long time
supposed that the changes in the position assumed by the needle at
any particular point on the earth’s surface might be conceived as
resulting from regular laws of periodicity, having for their arguments,
Ist, a great magnetic cycle of several centuries, depending on un-
known, and perhaps internal movements or relations; and 2ndly, on
the periodic alternations of heat and cold depending on the annual
and diurnal movements of the sun. ‘The discovery of the affection
of the needle by the aurora borealis, and of the existence of minute
and irregular movements, which might be referred either to unper-
ceived auroras or to other local and temporary causes, sufficed to
show that the laws of terrestrial magnetism are not so simple as to
admit of this summary form of expression; and the important dis-
covery, first announced, we believe, by Baron Von Humboldt, that
those temporary changes take place simultaneously at great distances

in point of locality, a discovery which has since been remarkably

confirmed and extended to very great intervals of distance, so as to
include the whole extent of the European continent, by Gauss and
Weber, and their coadjutors of the German Magnetic Association,
has sufficed to show that the gist of the inquiry lies deeper, and
depends upon relations far more complex, while at the same time
the dominion of what might previously have been regarded as local
agency, would require, in the new views consequent on the esta-
blishment of these facts, to be extended far beyond what ordinary
usage would authorize as a just application of that epithet.

138 Royal Society.

For a long time in the history of terrestrial magnetism the varia-
tion alone was attended to. The consideration of the dip was then
superadded ; but the observation of this element being more difficult
and delicate, our knowledge of the actual and past state of the dip
over the earth’s surface is lamentably deficient. It has lately ap-
peared, however, that this element can be observed with considerable
approximation, though not with nicety, at sea, so that no reason sub-
sists why materials for a chart of the dip analogous to that of varia-
tion should not be systematically collected. Lastly, the intensity
has come to be added to the list of observanda; and from the great
facility and exactness with which it can be determined, this branch
of magnetic knowledge has in fact made most rapid progress.

These three elements, the Horizontal Direction, the Dip, and
' the Intensity, require to be precisely ascertained before the magnetic
state of any given station on the globe can be said to be fully deter-
mined. Nor can either of them, theoretically speaking, be said to
be more important than the others, though the direction, on account
of its immediate use to navigators, has hitherto had the greatest
stress laid upon it, and been reduced into elaborate charts. A chart
of the lines of total intensity has been recently constructed by Major
Sabine.

All these elements are, at each point, now ascertained to be in
a constant state of fluctuation, and affected by those transient and
irregular changes which are above alluded to; and the investigation
of the laws, extent, and mutual relations of these changes is now
become essential to the successful prosecution of magnetic discovery,
for the following reasons.

Ist. That the progressive and periodical being mixed up with
the transitory changes, it is impossible to separate them so as to ob-
tain a correct knowledge and analysis of the former, without taking
express account of and eliminating the latter, any more than it would
be practicable to obtain measures of the sea-level available for an
inquiry into the tides, without destroying the irregular fluctuation
produced by waves.

Qndly. That the secular magnetic changes cannot be concluded
from comparatively short series of observations without giving to
those observations extreme nicety, so as to determine with perfect
precision the mean state of the elements at the two extremes of the
period embraced, which, as already observed, presupposes a know-
ledge of the casual deviations.

8rdly. It seems very probable that discordances found to exist
between results obtained by different observers, or by the same at
different times, may be, in fact, not owing to error of observation,
but may be due to the influence of these transitory fluctuations in
the elements themselves.

4thly and lastly. Because the theory of these transitory changes
is in itself one of the most interesting and important points to which
the attention of magnetic inquirers can be turned, as they are no
doubt intimately connected with the general causes of terrestrial
magnetism, and will probably lead us to a much more perfect know-
ledge of those causes than we now possess.

Royal Society. 139

Actuated by these impressions, on the occasion of a letter ad-
dressed by Baron Von Humboldt to His Royal Highness the Duke of
Sussex, P.R.S*., the Council of this Society, on April 13, 1837, re-
solved to apply to Government for aid in prosecuting, in conjunction
with the German Magnetic Association, a series of simultaneous ob-
servations; and in consequence of an application founded on such
their resolution, a grant of money was obtained for the purchase of
instruments for that purpose. By reason, however, of the details
and manipulations of the methods then recently introduced into
magnetic observations by Gauss being at that time neither com-
pletely perfected, nor their superiority over the old methods fully
established by general practice, the precise apparatus to be employed
in these operations was not at the time agreed upon, and was still
under discussion, subject to the report of the Astronomer Royal on
the performance of an instrument on Gauss’s principle established at
Greenwich, at the time when the subject in its present more ex-
tended form was referred by the Council to this Joint Committee, so
that the grant in question has not, in point of fact, been employed
or called for. 'The Committee consider this as in some respects for-
tunate, as in consequence of the delay time has been given for a
much maturer consideration of the whole subject ; and should it now
be taken up as a matter of public concern, they consider that it will
be necessary to provide for a more continuous and systematic series
of observations, by observers regularly appointed for the purpose,
and provided with instruments and means considerably more costly
than those contemplated on the occasion in question.

On the general advisableness of calling for public assistance in
the prosecution of the extensive subject of terrestrial magnetism, in
both the modes referred to them for their consideration, (viz. by
magnetic observatories established at several stations properly se-
lected on land, and by a naval expedition expressly directed to such
observations in the Antarctic Seas,) your Committee are fully agreed.
They consider the subject to have now attained a degree of theo-
retical as well as of practical importance, and to afford a scope for
the application of exact inquiry which it has never before enjoyed,
and which are such as fully to justify its recommendation by the
Royal Society to a revival of that national support to which we are
indebted for the first chart of variations constructed by our illustrious
countryman Halley in a.p. 1701, on the basis of observations col-
lected in a voyage of discovery expressly equipped for that purpose
by the British Government.

As regards the first branch of the question referred to their con-
sideration, they are of opinion that the stations which have been
suggested to them, viz. Canada, St. Helena, the Cape, Van Diemen’s
Land, and Ceylon (or Madras), are well selected, and perhaps as nu-
merous as they could venture to recommend, considering the expense
which would require to be incurred at each, and that in each of

* A translation of Baron Von Humboldt’s letter was given in Lond. and
Edinb. Phil. Mag, vol. ix. p. 42.—Enpir.

140 Royal Society.

these stations it would be desirable, 1st, That regular hourly obser-
vations should be made (at least during the daytime) of the fluctua-
tions of the three elements of variation, dip, and intensity, or their
equivalents, with magnetometers on the more improved construction,
during a period of three years from their-commencement.

2Qndly. That on days, and on a plan appointed, agreed on in
concert with one another, and with European observatories, the
fluctuations of the same elements should be observed during twenty-
four successive hours, strictly simultaneous with one another, and at
intervals of not more than five minutes.

3rdly. That the absolute values of the same elements shall be
determined at each station, in reference to the fluctuating values
above mentioned, with all possible care and precision, at several
epochs comprehended within the period allowed.

4thly. That in the event of a naval expedition of magnetic dis-
covery being despatched, observations be also instituted at each fixed
station, in correspondence with, and on a plan concerted with, the
Commander of such Expedition.

As regards the second branch of the subject referred to them,
viz. the proposal of an Antarctic voyage of magnetic research, they
are of opinion, as already generally expressed, that such a voyage
would be, in the present state of the subject, productive of results
of the highest importance and value; and they ground this opinion
on the following reasons :—

1st. That great and notorious deficiencies exist in our knowledge
of the course of the variation lines generally, but especially in the
Antarctic seas, and that the true position of the southern magnetic
pole or poles can scarcely even be conjectured with any probability
from the data already known.

Qndly. That our knowledge of the dip throughout those regions,
and the whole southern hemisphere, is even yet more defective, and
that even such observations of this element as could be procured at
sea, still more by landing on ice, &c., would have especial value.

3rdly. That the intensity lines in those regions rest on observa-
tions far too few to justify any sure reliance on their courses over a
large part of their extent, and over the rest are altogether con-
jectural. Nevertheless that there is good reason to believe in the
existence and accessibility of two points of maximum intensity in
the southern as in the northern hemisphere, the attainment of which
would be highly interesting and important.

4thly. That a correct knowledge of the courses of these lines,
especially where they approach their respective poles, is to be re-
garded as a first and, indeed, indispensable preliminary step to the
construction of a rigorous and complete theory of terrestrial mag-
netism.

5thly. That during the progress of such an expedition, oppor-
tunities would of necessity occur (and should be expressly sought)
to observe the transitory fluctuations of the magnetic elements in
simultaneous conjunction with observations at the fixed stations and
in Europe, and so to furnish data for the investigation of these

Geological Society. 141

changes in localities very unlikely to be revisited for any purposes
except those connected with scientific inquiries.

Your Committee, in making this Report, think it unnecessary
to go into any minute details relative to the instruments or other
materiel required for the proposed operations, still less into those
of the conduct of the operations themselves. Should such be re-
quired from them, it will then be time to enter further into these
and other points, when the Committee will most readily devote them-
selves to the fullest consideration of the subject.

J. F. W. Herscuet,
Chairman of the Joint Physical and
Meteorological Committee.

Resoturions.—1. That this Report be received and approved.

2. That the Council, deeply impressed with the importance of the
scientific objects which might be attained by an Antarctic Expedi-
tion, particularly by the institution of magnetic observations in
southern regions, do earnestly recommend that Her Majesty’s Go-
yernment be pleased to direct the equipment of such an expedition.

3. That the imperfect state of our present knowledge of the
amount and fluctuations of the magnetic elements, renders the esta-
blishment of fixed magnetical observatories, for a limited time, at
various points of the earth’s surface, highly desirable, particularly
in Canada, St. Helena, Van Diemen’s Land and Ceylon, and at the
Cape of Good Hope, and that the Council do earnestly recommend
Her Majesty’s Government to cause such observatories to be esta-
’ blished.

4. That a deputation, consisting of the President, Treasurer,
and Secretaries of the Society, Sir John F. W. Herschel, the Chair-
man, and Major Sabine and Mr. Wheatstone, the Secretaries of the
joint Committee of Physics and Meteorology, be requested to com-
municate the above Resolutions to Lord Melbourne, and to urge on
the Government the adoption of the measures therein proposed.

GEOLOGICAL SOCIETY.

Nov. 21, 1838.—A paper was first read “ On the Jaws of the
Thylacotherium Prevostii* (Valenciennes) from Stonesfield,”’ by
Richard Owen, Esq., F.G.S., Hunterian Professor, Royal College of
Surgeons.

Doubts having been recently expressed by M. de Blainvillet, from
inspection of casts, respecting the mammiferous nature of the fossil
jaws found at Stonesfield, and assigned to the Marsupialia by Baron
Cuvier, Mr. Owen brought the paper before the Society, to meet the
objections and give a detailed account of the fossils from a careful
inspection of the originals. In this communication, however, he
confined his description chiefly to the jaws of one of the two genera
which have been discovered at Stonesfield, and characterized by

* Comptes Rendus, 1838 ; Second Semestre, No. 11, Sept. 10, p. 580.
+ Ibid., No. 8, Aofit 20, p. 402 et seg.; No. 9, Planche; No. 17,
Oct. 22, p. 727; No. 18, Oct. 29, p. 750.

142 Geological Society :—Prof. Owen on the Jaws of

having eleven molars in each ramus of the lower jaw, reserving to a
future occasion an account of the remains of the other genus*.

Mr. Owen commences by observing that the scientific world pos-
sesses ample experience of the truth and tact with which the illus-
trious Cuvier formed his judgements of the affinities of an extinct
animal from the inspection of a fossil fragment; and that it is only
when so distinguished a comparative anatomist as M. de Blainville
questions the determinations, that it becomes the duty of those who
possess the means to investigate the nature of the doubts, and re-
assure the confidence of geologists in their great guide.

When Cuvier first hastily examined at Oxford, in 1818, one of
the jaws described in this paper, and in the possession of Dr. Buck-
land, he decided that it was allied to the Didelphys (me sembleérent
de quelque Didelphet) ; and when doubts were raised by M. Con-
stant Prevost, in 18244, relative to the age of the Stonesfield slate,
Cuvier, from an examination of a drawing made for the express pur-
pose, was confirmed in his former determination ; but he added, that
the jaw differs from that of all known carnivorous Mammalia, in ha-
ving ten molars in a seriesin the lower jaw: (“il [the drawing] mecon-
firme dans l’idée que la premiére inspection m’en avoit donnée. C’est
celle d’un petit carnassier dont les macheliéres ressemblent beaucoup
& celles des sarigues; mais il y a dix de ces dents en série, nombre
que ne montre aucun carnassier connu.” Oss. Foss. 111. 349. note.)
It is to be regretted that the particular data, with the exception of
the number of the teeth, on which Cuvier based his opinion, were not
detailed; but he must have been well aware that the grounds of his
belief would be obvious, on an inspection of the fossil, to every com-
petent anatomist: it is also to be regretted that he did not assign to
the fossil a generic name, and thereby have prevented much of the
reasoning founded on the supposition that he considered it to have
belonged to a true Didelphys.

Mr. Owen then proceeded to describe the structure of the jaw;
and he stated that having had in his possession two specimens of the
Thylacotherium Prevostii belonging to Dr. Buckland, he has no hesi-
tation in declaring that their condition is such as to enable any ana-
tomist conversant with the established generalizations in compara-
tive osteology, to pronounce therefrom not only the class but the
more restricted group of animals to which they have belonged. The
specimens plainly reveal, first, a convex articular condyle ; secondly,
a well-defined impression of what was once a broad, thin, high, and
slightly recurved, triangular, coronoid process, rising immediately
anterior to the condyle, having its basis extended over the whole of
the interspace between the condyle and the commencement of the
molar series, and having a vertical diameter equal to that of the ho-
rizontal ramus of the jaw itself : this impression also exhibits traces

* This has since been read, and an abstract of it will appear in our next
number.—Epir.

+ Ossemens Foss., tome ili. p. 349.

t Annales des Sciences Nat., Avril, 1825; also the papers of Mr. Bro-
derip and Dr. Fitton in the Zoological Journal, 1828, vol. iii., p. 409.

the 'Thylacotherium Prevostii from Stonesfield. 143

of the ridge leading forwards from the condyle and the depression
above it, which characterizes the coronoid process of the zoophagous
marsupials; thirdly, the angle of the jaw is continued to the same
extent below the condyle as the coronoid process reaches above it,
and its apex is continued backwards in the form of a process;
fourthly, the parts above described form one continuous portion with
the horizontal ramus of the jaw, neither the articular condyle nor
the coronoid being distinct pieces as in reptiles. These are the
characters, Mr. Owen believes, on which Cuvier formed his opinion
of the nature of the fossil; and they have arrested the attention of
M. Valenciennes in his endeavours to dissipate the doubts of M. de
Blainville*.

From the examination of a cast, the latter, however, has been in-
duced to infer that there is no trace of a convex condyle, but in
place thereof an articular fissure, somewhat as in the jaws of fishes;
that the teeth, instead of being imbedded in sockets, have their fangs
confluent with or anchylosed to the substance of the jaws, and that
the jaw itself presents evident traces of the composite structure.

In answer to the first of these positions, Mr. Owen states that the
portion of the true condyle which remains in both the specimens of
Thylacotheriam examined by Cuvier and M. Valenciennes, clearly
shows that the condyle was convex, and not concave. It is situated
a little above the level of the grinding surface of the teeth, and pro-
jects beyond the vertical line, dropped from the extremity of the coro-
noid process, but not to the same extent as in the true Didelphys.
In the specimen examined by M. Valenciennes, the condyle corre-
sponds in position with that of the jaw of the Dasyurus rather than
the Didelphys; it is convex, as in mammiferous animals, and not
concave as in oviparous. The entire convex condyle exists in the
specimen belonging to the other genus, Phascolotherium, now in
the British Museum, but formerly in the cabinet of Mr. Broderip.
Mr. Owen is of opinion that the entering angle or notch, either above
or below the true articular condyle, has been mistaken for ‘‘ une
sorte d’échancrure articulaire, un peu comme dans les poissons.”

The specimen of the half-jaw of the Thylacothere examined by
M. Valenciennes, like that [the drawing of?] which was trans-
mitted to Cuvier, presents the inner surface to the observer, and ex-
hibits both the orifice of the dental canal and the symphysis ina per-
fect state. The foramen in the fossil is situated relatively'more for-
ward than in the recent Opossum and Dasyure, or in the Placental
Insectivora, but has the same place as in the marsupial genus Hypsi-
prymnus. The symphysis is long and narrow, and is continued for-
ward in the same line with the gently convex inferior margin of the
jaw, which thus tapers gradually to a pointed anterior extremity,
precisely as in the jaws of the Marsupial Insectivora. In the relative
length of the symphysis, its form and position, the jaw of the Thy-
lacotherium precisely corresponds with that of the Didelphys.

* Comptes Rendus, 1838; Second Semestre, No. 11, Sept. 10, p. 527
et seq.

144 Geological Society.

In addition, however, to these proofs of the mammiferous nature
of the Stonesfield remains, and in part of their having belonged to
Marsupialia, Mr. Owen stated that the jaws exhibit a character
hitherto unnoticed by the able anatomists who have written respect-
ing them, but which, if co-existent with a convex condyle, would
serve to prove the marsupial nature of a fossil, though all the teeth
were wanting.

In recent marsupials the angle of the jaw is elongated and bent
inwards in the form of a process, varying in shape and development
in different genera. In looking, therefore, directly upon the infe-
rior margin of the marsupial jaw, we see in place of the edge of a
vertical plate of bone, a more or less flattened triangular surface or
plate of bone extended between the external ridge and the internal
process or inflected angle. In the Opossum this process is triangu-
lar and trihedral, and directed inwards with the point slightly curved
upwards and extended backwards, in which direction it is more pro-
duced in the small than in the large species of Didelphys.

Now, if the process from the angle of the jaw in the Stonesfield
fossil had been simply continued backwards, it would have resembled
the jaw of an ordinary placental carnivorous or insectivorous mam-
mal; but in both specimens of Thylacotherium the half-jaws of
which exhibit their inner or mesial surfaces, this process presents
a fractured outline, evidently proving that when entire it must have
been produced inwards or mesially, as in the Opossum.

Mr. Owen then described in great detail the structure of the teeth,
and showed, in reply to M. de Blainville’s second objection, that they
are not confluent with the jaw, but are separated from it at their
base by a layer of matter of a distinct colour from the teeth or the
jaw, but evidently of the same nature as the matrix ; and secondly,
that the teeth cannot be considered as presenting an uniform com-
pressed tricuspid structure, and being all of one kind, as M. de
Blainville states, but must be divided into two series as regards their
composition. Five if not six of the posterior teeth are quinque-cus-
pidate and are molares veri; some of the molares spurii are tricuspid
and some bicuspid, asin the Opossums. An interesting result of this
examination is the observation that the five cusps of the tuberculate
molares are not arranged, as had been supposed, in the same line,
but in two pairs placed transversely to the axis of the jaw, with the
fifth cusp anterior, exactly as in the Didelphys, and totally different
from the structure of the molares in any of the Phoce, to which these
very small Mammalia have been compared: and in reference to this
comparison, Mr. Owen again calls attention to the value of the cha-
racter of the process continued from the angle of the jaw, in the
fossils, as strongly contradistinguishing them from the Phocide, in
none of the species of which is the angle of the jaw so produced. The
Thylacotherium differs from the genus Didelphys in the greater num-
ber of its molars, and from every ferine quadruped known at the time
when Cuvier formed his opinion respecting the nature of the fossil.
This difference in the number of the molar teeth, which Cuvier urgedas
evidence of the generic distinction of the Stonesfield mammiferous

;
.
:

Geological Society. 145

fossils, has since been regarded as one of the proofs of their Saurian
nature ; but the exceptions by excess to the number seven, assigned
by M. de Blainville to the molar teeth in each ramus of the lower
jaw of the insectivorous Mammalia, are well established, and have
been long known. The insectivorous Chrysochlore, in the order
Fere, has eight molars in each ramus of the lower jaw; the insec-
tivorous Armadillos have not fewer ; and in one subgenus (Priodon)
there are more than twenty molar teeth on each side of the lower
jaw. The dental formule of the carnivorous Cetacea, again, de-
monstrate the fallacy of the argument against the mammiferous cha-
racter of the Thylacotherium founded upon the number of its molar
teeth. From the occurrence of the above exceptions in recent pla-
cental Mammalia, the example of a like excess in the number of
molar teeth in the marsupial fossil ought rather to have led to the
expectation of the discovery of a similar case among existing mar-
supials, and such an addition to our zoological catalogues has, in
fact, been recently made. In the Australian quadruped described
by Mr. Waterhouse under the name of Myrmecobius* an approxima-
tion towards the dentition of the Thylacotherium is exemplified, not
only in the number of the molar teeth, which is nine on each side of
the lower jaw in the Myrmecobius, but also in their relative size,
structure, and disposition. Lastly, with respect to the dentition,
Mr. Owen says it must be obvious to all who inspect the fossil and
compare it with the jaw of a small Didelphys, that contrary to the
assertion of M. de Blainville, the teeth and their fangs are arranged
with as much regularity in the one as in the other, and that no ar-
gument of the Saurian nature of the fossil can be founded on this
part of its structure.

With respect to M. de Blainville’s assertion that the jaw is com-
pound, Mr. Owen stated, that the indication of this structure near
the lower margin of the jaw of the Thylacotherium is not a true
suture, but a vascular groove similar to that which characterizes
the lower jaw of Didelphys, Opossum, and some of the large species
of Sorex.

In a memoir to be brought forward on another occasion, Mr.
Owen intends to describe the other genus found at Stonesfield, and
for which, on account of its marsupial affinities, he proposes the name
of Phascolotherium.t

A notice by R. W. Fox, Esq., was afterwards read, ‘‘ On the
Formation of Metallic Veins by Voltaic Agency.’’t

In this communication Mr. Fox says, that he has succeeded not
only in forming well-defined metalliferous veins in a crack in the
middle of masses of clay by means of voltaic agency, butalso in im-
parting to the clay a laminated or schistose structure; the veins and
laminz being perpendicular to the voltaic forces. In some instances

[* See Lond, & Edinb. Phil. Mag, vol. ix. p. 520; vol. xi. p. 200.—Epir. ]

[+ A list of the fossils associated with these marsupial remains in the
Stonesfield slate, drawn up by Mr. De la Beche, will be found in Phil. Mag.
and Annals, N. S. vol. vii. p. 257.—Epir.]

[{ See Lond. and Edinb. Phil. Mag, vol. xi. p. 203.—Ep1v.]
Phil. Mag. S, 3. Vol. 14. No. 86. Feb. 1839.

146 Geological Society.

only a pair of plates, or in preference copper pyrites and zinc, were
employed to produce the voltaic action ; but a constant battery con-
sisting of several pairs of plates was much more effective. Among
the veins thus produced in clay, Mr. Fox mentions oxide and car-
bonate of copper, carbonate of zinc, oxides of iron and tin. Veins of
carbonate of zinc were formed, sufficiently firm to admit of being
taken out in plates of the size of a shilling. Mr. Fox then describes
a vein formed in pipeclay, by Mr. Jordan, by five pairs of cylinders,
in three weeks. The clay divided an earthenware vessel into two
cells, into one of which, containing the copper plate, a solution of
sulphate of copper was put; and into the other, or zinc cell, a solu-
tion of common salt. Well-defined veins were thus produced of
carbonate and oxide of copper, and carbonate of zinc, parallel to the
laminz into which the clay divided; as well as another of carbonate
and oxide of copper at right angles to them. On dividing the mass
of clay in the direction of the principal horizontal vein, the carbonate
of zinc was found on the negative side, or towards the copper plate;
and the carbonate of copper nearest the zinc plate: and as the for-
mer must have been derived from the zinc plate, it is curious to ob-
serve such a complete transposition of the respective metals.

Mr. Fox is of opinion that these results have a strong bearing on
the numerous mineral veins and beds which are found conformable
to the direction of the lamin of the containing rocks, as well as on
those veins which traverse the laminz of the conformable veins.

An extract was afterwards read from a letter addressed by Captain
Alexander to the Secretary, explanatory of casts of portions of
Mastodon teeth from the crag, and on the occurrence of a particu-
lar bed containing Echini in the coralline crag * at Sudbourne.

The larger cast was taken from a Mastodon tooth found on the
shore at Sizewell Gap, about seven miles from Southwold. When
the original came into Captain Alexander’s possession, crag adhered
to it in considerable quantity; and he has no doubt that it had been
washed from Easton, about 14 mile north of Southwold. The weight
of the tooth is 2]bs. 53 oz., its length is about 6 inches, and its
breadth 34 inches; and although it had been washed eight miles,
only three of the crowns had been injured. The other cast is from a
fragment of a young tooth found by the author in the crag at Bra-
merton.

Capt. Alexander found also the canine tooth of a large carnivo-
rous animal in the crag at Easton. At Bramerton he obtained also
five crabs, three of which were almost perfect. At Sudbourne, near
Orford, in a bed of very fine coralline crag, he found several beau-
tiful Echini; and in a thin, argillaceous layer in the centre of the
same bed, the greater part of the vertebral column of a fish, the re-
mains of crabs, and the ear bone of a whale, which had apparently
been water-worn before it was enclosed in the crag. To this stratum
Captain Alexander calls particular attention, as he believes it would
be found to be rich in organic remains, if it were properly examined.

Dec. 5th 1838.—A paper was first read, entitled ‘‘ A few brief

[* See Lond. and Edinb. Phil. Mag., vol. vii. p. 838.—Ebir. }

ly gp en oe, ae.

—

—

aoe

oem

ws

Geological Society. 147

Remarks on the Trap Rocks of Fife,” by the Rev. John Fleming,
D.D., and communicated by Charles Lyell, Esq., V.P.G.S.

The trap rocks of Fifeshire are referred by Dr. Fleming to three
distinct epechs of volcanic action; and he says that the products of
each epoch are not more decidedly characterized by dissimilarity in
their relationship to the associated sedimentary rocks than by dif-
ferences in their composition.

The traps of the first epoch occupy the northern portion of the
county from Stratheden to the estuary of the Tay, constituting the
eastern extremity of the Ochils. They appear to be coeval with the
grey sandstone (Arbroath pavement), and to rest upon, as well as to
be variously associated with the old red sandstone, and to be covered
by the yellow sandstone which supports the mountain limestone.
Viewed on a great scale, they consist of amygdaloids containing ir-
regular masses of porphyry, clay-stone, clink-stone, compact felspar,
green-stone, and trap tuff: they also contain thin layers of slate-
clay and grey sandstone. The whole of the igneous rocks are de-
cidedly stratified ; and though the beds are thick and variously bent,
they have, in general, the same dip as the superior and inferior sedi-
mentary formations. The materials of which they are composed,
Dr. Fleming conceives were spread out under water, partly as lava
and partly as ashes; and that several of the peculiarities of rocky
structure have been produced by corpuscular action.

Two vertical greenstone veins traverse this group in an easterly
direction. One of them may be traced along the north side of the
Ochils from the neighbourhood of Newburgh by Norman’s Law to
Luthrie, a distance of nearly six miles: the other, observable at
Alva and Dollard, on the south side of the Ochils, may be traced
nearly forty miles by Monymeal to Hilton Bridge, north of Cupar.
Several cross veins of greenstone and felspar likewise occur.

The trap rocks of the second epoch form the southern margin of
Stratheden, and may be considered as constituting a ridge parallel
with the Ochils, from near St. Andrews to Stirling; but several
branches or patches of the same age have been observed in the
counties on the south of the Forth. These traps consist almost ex-
clusively of greenstone, which in a few instances is earthy and
amygdaloidal. They cover, in many places, the lower beds of the
coal-measures; on the East Lomond they are intermixed with the
mountain limestone ; andat Wemyss Hall Hill, south of Cupar, they
overlap the limestone, and are in contact with the yellow sandstone.

These two groups of trap rocks, the author is of opinion, were
produced while the associated strata of old red sandstone and coal-
measures were horizontal; and that they have undergone, equally
with the sedimentary formations, the movements which gave the
strata of the Ochils and the ridge south of Stratheden the southerly
dip. He is also of opinion, that the greenstone of the second group
may have furnished materials for the great veins, which traverse the
older one.

The traps of the third epoch occur chiefly along the shores of the
Forth, and in the higher coal-measures. They consist of basalt with

L 2

148 Geological Society: Nat. Hist. Soc. of Liverpool

olivine, amygdaloid, greenstone, wacke, and trap tuff; and they fre-
quently contain fragments of limestone, flinty slate, slate-clay, bitu-
minous shale, sandstone, and coal. They appear to have been pro-
duced while the associated sedimentary strata were horizontal, and
to have undergone with them the same disturbing movements*.

An account of Footsteps of the Chirotherium+, and other unknown
animals lately discovered in the quarries of Storeton Hill, in the pen-
insula of Wirrall, between the Mersey and the Dee, communicated
by the Natural History Society of Liverpool, and illustrated with
drawings by John Cunningham, Esq., was then read.

In the early part of last June, there were discovered in the Store-
ton quarries, on the under surface of several large slabs of sandstone,
highly relieved casts of what the workmen believed to have been human
hands; and the circumstance having been made known to the Na-
tural History Society of Liverpool, a committee was appointed, who
drew up the report communicated to this Society.

The peninsula of Wirrall consists of new red sandstone; and to-
wards the northern extremity, the formation may be separated into
three principal divisions. The lowest is composed of beds, slightly
inclined towards the east, of red or variegated sandstone, occasionally
abounding with pebbles partly derived from the coal-measures ; and
in the bottom strata either angular or little water-worn. ‘Seams of
marl are very rare in this division, the argillaceous matter being con-
fined to nodules or concretions of clay of the same colour as the
sandstone.

The middle division consists of white or yellow sandstone, in some
places argillaceous, and frequently containing round concretions of
clay, and pebbles. The strata are separated by seams of white or
mottled clay, occasionally almost imperceptible, but sometimes se-
veral inches thick.

The uppermost division is formed of red or variegated sandstone,
inclosing also nodules of clay and pebbles of quartz ; and it abounds
with strata of red marl.

The Storeton quarries are situated in the middle division; and the
casts which have hitherto been noticed, occurred on the under sur-
face of three beds of sandstone, about two feet thick each. The
strata incline 8° to the north-east, but they are traversed by several
faults, which range in the strike of the beds. The authors of the re-

* For further particulars, see Mackenzie on the Ochils, Mem. Wern.
Soc., vol. ii. p. 1; Fleming on Scales in the Old Red Sandstone of Fife-
shire, Edinb. Journ. Nat. and Geograph. Science, Feb. 1831; and on
the Mineralogy of the Neighbourhood of St. Andrews, Mem. Wern. Soc.,
vol. ii. p. 145; also Neill’s Daubuisson, p. 215.

+ This name was first applied provisionally by Professor Kaup, to si-
milar casts discovered, towards the end of 1834, in the sandstone quarries
at Hesseberg, near Hildburghausen. See Dr. F. R.L. Sickler’s Letter to
Blumenbach, 1834; also, Die Plastik der Urwelt im Werrathale bei
Hildburghausen, with plates by C. Kepler, and an introduction by Dr.
Sickler, Ist part, 1836; and Dr. Buckland’s Bridgewater Treatise, 1836.

on Footsteps of the Chirotherium. 149

port are of opinion, that each of the thin seams of clay in which the
sandstone casts were moulded, formed successively a dry surface,
over which the Chirotherium and other animals walked, leaving im-
pressions of their footsteps ; and that each layer was submerged by
a depression of the surface. The lowest seam of clay was so thin,
that the marks penetrated into the subjacent sandstone. The fol-
lowing account is then given of a hind foot and a fore foot, selected
from slabs in the Museum of the Royal Institution, Liverpool.

Hind Foot, consisting of five digits; one of which, from its resem-
blance to a human thumb, has been generally distinguished by that
designation.

Inches.

Total length from the root of the thumb to the point of the se-
cond toe. dg

Extreme breadth from the ‘point of the thumb to the point ‘of
PME Yue fair asks ajc atetacerss Sf aerate co oUaheretiaressts 6°

Prcamuhvacross lle tOCSs one ie sl eve.ia'< cela asia etait io (este et suelels oe 6 5

Preddtheacross the palm ..2.atisps 4 hoes.) tinlete 2 clopeel Aereles ©

Length of the curved line extending from the root of the thumb
SNE Oe raeret cree aes et taeie obit icete aks eee aes matali

Breadth of theball of theithumb*).-.-. 2. 2.7). pees ete

Relief of the ball of the thumb from the surface of the slab. ..

Length of the first toe from the root to the point ..........

Length of the second ditto -.......... 2. ss ee cee eee wenss

Penn or the third: ditto ssl. os dtiie Se SRN ANe o

Beart ofthe fourth ditto; oo.) 262) 2 ask ei ae ee ee

Average breadth of the first three toes............--++..--

Average breadth of the fourth toe rather less than. .

Relief of the second tee, which presents the sreatest promi-
ETE IR aL ts AS Men 2k rn Shi BBA er ct 15
One hind foot has been observed which measured 12 inches in its

greatest length.

Judging from the appearance of the casts, the sole of the foot
must have been amply supplied with muscles, the casts of the ball
of the thumb and the phalanges of the fingers being prominent.
The digit, which has been called a thumb, is of a tapering shape,
and is bent backwards near the extremity, where it ends in a point.
It is extremely smooth, and there is no satisfactory evidence of either
a nail oraclaw. ‘The toes are thick and strong, and had probably
three phalanges each, and at the terminations are traces of stout,
conical nails or claws. The sole of the foot is supposed to have
been covered bya slightly rugose skin, the folds of which are stated
to be distinctly visible in the casts of the toes.

Fore Foot. Perfect impressions of the fore feet are extremely
rare, owing either to the animal having used those feet lightly, or
to the impressions having been obliterated by the tread of the hind
feet. The best preserved cast exhibits a thumb and three toes,
being deficient of the fourth. The dimensions, which are generally
half those of the hind foot, are as follows ;

[op ree)

ble Alb to|-1o|—

me ho or
role

150 Geological Society: Sir P. Grey Egerton on the

Inches.
Length from the root of the thumb to the point of the second
EOL Dic Ph a AE ATU io Sinan one Abb fc ong ae ete Aap te Tee een 43
Total breadth not ascertained in consequence of the absence of
the fourth toe.

Breadth of the palm. ......,>'-'eis'- siste qiin® -ian oe ese) sinaeog anne
Length.of the thumb. ...... 5. sees secs ee cece weet eens 25
Breadth ofthe ball of the thumbs... sii). 4, 2:9:39--)- Penile 1

Length of the first toe ©. ...- eens ssceeeee eee Yt 2

Length of the second toe .......-.-+.+0-- od * inoreh Seah 25
Lieneth of the third to€.. 6.00 ci. © S- .. dodaresle ns 5) 9.9 >a
Greatest breadth, of the to@8.ic.. .)2:,5:«,0\s,ciei6 bspe'sin» wis oo wnlale 2

The thumb is slightly bent back, and pointed, and the toes were
armed with nails.

Traces of one animal have been observed in a continuous line
on a slab ten yards long. The length of the step varies a little,
but in general, the distance between the point of the second toe
of one hind foot and the point of the same toe in the hind foot
immediately in advance, is between 21 and 22 inches. Each fore
foot is placed directly in front of the hind, and the thumbs of both
extremities are always towards the medial line of the walk of the
animal. Some further observations are given by the authors with
respect to the progression of the animal, on the supposition that the
digit conjectured to be a thumb, was really the first. Conceiving
such to be the case, they state, that the animal must have crossed
its feet three inches in walking, for the right fore and hind feet are
placed 14 inch on the left side of the medial line, and the left fore
and hind feet 11 inch on the right side of the same line.

The casts of the Chirotherium, although the most remark-
able, are by no means the most numerous, which exist on the
Storeton sandstones. Many large slabs are crowded with casts in
rilievo, some of which are supposed to have been derived from the
feet of saurian reptiles, and others from those of tortoises. Occa-
sionally the webs between the toes can be distinctly traced. ‘It is
impossible,” say the authors of the report, ‘‘ to look at these slabs
and not conclude, that the clay beds on which they rested, must have
been traversed by multitudes of animals, and in every variety of di-
rection.”

A note by Mr. James Yates was then read, giving a brief account
of sketches of four differently characterized footsteps, traced from
casts procured at Storeton, each of which is distinct both from the
casts of the Chirotherium and the web-footed animal mentioned in
the preceding report.

A paper was afterwards read “‘ On two Casts in Sandstone of the
impressions of the Hind Foot of a gigantic Chirotherium, from the
New Red Sandstone of Cheshire,” by Sir Philip Grey Egerton,
Bart., M.P., F.G.S.

These specimens first came under the notice of Colonel Egerton
about 1824, and they were placed in the author’s cabinet in 1836;
but it was not until the recent discovery of the Chirotherium at

Chirotherium Herculis. 151

Storeton, that their true nature was suspected. The exact locality,
at which the specimens were discovered, is not known; but it is pro-
bable, that they were obtained from the neighbourhood of Colonel
Egerton’s residence, near Tarporley, and from one of the beds of
sandstone, which alternate with the red and green marls in the upper
part of the new red system in that part of Cheshire.

The casts, which consist of a rather soft and coarse sandstone,
were evidently formed in the impressions of two hind feet; and
though they have suffered from exposure to the weather for twelve
years, yet they are sufficiently perfect to have enabled Sir Philip
Egerton to take the measurements of the different parts, and draw
up the accompanying comparative table. It is necessary to state,
that though he preserves the use of the term thumb for the conve-
nience of comparison with previous descriptions, yet he is of opinion
that the marginal digit which has been so designated, is not the re-

presentative of the fifth, but of the first toe.
Large Chi-

Lal Hessberg Storeton rotherium
Direction of the Measurements. Chirothe- Chirothe- from near
. rium, rium. Tarporley.
Length from the heel to the point of the 7 8

Die ABBR Cites cetelee selee ad 8 7 ., 1b 0

Length from the heel to the point of the
“UAP ET Yelle AR Be eS et 0 Ont tions Lore fy art te: 4 8 0

Length from the heel to the angle between
the Ist and 2nd f0€S .;-cess-c0er.c0 <2 Lek dd Rtas 10 0
nd an era t0e8. + 24 see Oe Ten)
——————— 38rd and 4th toes 4 0 .. 5 3 .. 11 O

Greatest breadth across the insertions of
ED rh eA A OHA esa Di citar 2 he 8 5

h i he th

Eel geen pas el We Rape EE
Breadth from the thumb to point of 4thtoe 6 3 .. 6 0 .. 10 6
Breadth across the sole below the thumb., 3 6 .. 38 0 .. 6 0
Breadth from Ist toe-point to 4thtoe-point 4 6 .. 4 6 .. 9 O

From these measurements it appears, that considerable differences
exist in the three specimens of Chirotherium. Upon comparing the
footstep from Hessberg with that from Storeton, it will be found, that
the former is thicker and more clumsy than the latter; that the sole
is shorter and broader, and the toes wider and longer. The most
important discrepancy, however, is in the position of the thumb,
which is placed much nearer the heel in the Hessberg specimens
than in those from Storeton. The cast from near Tarporley re-
sembles the latter more than the former; it nevertheless differs con-
siderably in the proportion of the breadth to the length of the sole,
which is greater; and in the proportions of the length of the toes to the
length of the sole, which is less than in the Storeton specimens. It
is also distinguished by the greater divergence of the toes from each
other. From these differences and the gigantic size of the Tarporley
specimen, the author conceives that the animal which made the im-
pression was a distinct species; and he proposes for it, in compli-
ance with the adage ew pede Herculem, the name of Chirotherium
Herculis.

152 Intelligence and Miscellaneous Articles.

CAMBRIDGE PHILOSOPHICAL SOCIETY.

Nov. 5.—The anniversary meeting of this society was held on
Monday evening last, the Rev. Dr. Graham, the President, being in
the chair. The Treasurer’s report was read, and the audit confirmed ;
and the following officers were elected for the ensuing year :

Dr. Graham, President, (re-elected. )

Mr. Hopkins (re-elected),

Dr. Clarke, Vice-Presidents.
Prof. Cumming, }

Prof. Peacock, Treasurer.

Prof. Henslow,

Prof. Whewell, pss

Prof. Willis,

Rev. J. Power, i Dr. Bond, t
Prof. Miller, | a ‘Sg -~Dr. Paget, ba
Prof. Challis, = § Mr. Stokes, o 9
Rev. J. W. Barnes, =) Mr. Earnshaw, A 3
Prof. Sedgwick, J Mr.Garnons, J

Noy. 12.—Mr. Hopkins, one of the Vice-Presidents, in the chair.
Professor Whewell made a communication ‘‘ respecting certain kinds
of Architecture.”

Nov. 26.—Dr. Graham, the President, in the chair. A paper was
read by Mr. D. T. Gregory, of Trinity College, ‘‘ On the Logarithms
of Negative Quantities’: and a communication was made by Pro-
fessor Henslow on the formation of mineral veins, as illustrated by
a specimen of “ brown clay” from Suffolk.

Dec. 10.—Dr. Graham, the President, in the chair. A communi-
cation, by Mr. Holditch, of Caius College, was laid before the So-
ciety, “‘ On rolling curves.” Professor Willis, who stated the re-
sults at which Mr. Holditch had arrived, illustrated the subject by
models of revolving wheels of various forms, working in each other
by rolling contact. These forms may consist of one, two, three,
four, or more Jobes: the form which consists of one lobe, may be
an ellipse turning about its focus. A note on the Flora of Madeira,
by Mr. Lowe, in addition to his Memoir, published in the last Part
of the Society, was read; also the beginning of a paper by Mr.
Rothman, “On the climate of Italy.” Prof. Henslow also gave an
_ account of the structure of wasps’ nests.

XXVI. Intelligence and Miscellaneous Articles.

EQUIVALENT OF CARBON AND COMPOSITION OF NAPHTHALIN,
M™ Theard, Robiquet, and Dumas, in reporting upon the me-

moir of MM. Pelletier and Walter, having occasion to allude to
the composition of naphthalin, state that one of them some years since
analysed a very pure specimen of this substance, and found that
0°400 of it yielded 1°370 of carbonic acid and 0-222 of water; this

represents Carbon '.......4.- 94-76
Hydrogen........ 6°16

Intelligence and Miscellaneous Articles. 153

These numbers, it is observed, though very nearly approaching those
which give the formula C#? H'®, generally admitted, show an unusual
excess of carbon; this circumstance was notified to M. Laurent, who
was long occupied with naphthalin in theoretic considerations, and
it is to be regretted that it did not receive his attention.
The recent analysis of naphthalin by Liebig also exhibits the same
excess of carbon.
Canbonk ory sean 9A Snes I O42 he 9 46
Hydrogen ...... G2igaeioh Gil 671

100°5 100°3 100°7
The analysis of naphthalin is then decidedly different from that of
the formula attributed to it. M. Dumas therefore considered it
necessary to undertake some experiments on the naphthalin of resin,
in order to compare it with that of coal.
Five experiments upon the naphthalin from the resin oil gave:

re Il. Ill. IV. V.
Carbont2t 943997 Kei94:2.)) p94 27 een 9409 ne 949
iydromen. Gide eeGsde, Lon 626bi aw I6-Qewe. 01671

SS eee

100°5 100°5 100°53 100°1 100-
M. Dumas then again analysed coal naphtha, and the results were
|i

II. Ill
Carboni.) 94°55 nee 94:2... 9425S
Flydrogens.:)'630.).0: 2% (633.27.'s))) 6220

101-05 100°5 100°75
In some of these analyses the quantity of carbon only was deter-
mined, which introduced errors into the hydrogen, that are usually
avoided. As the hydrogen was never less than 6:2, it may be ques-
tioned whether the formula for naphthlalin ought not to be replaced
by that by Liebig, which is,
GE, PARE tO. 1528°7 ....) 94°23
EY cotieniaraesite ins MO bade do Sia7,

1622°3 100°

On the other hand, it may be readily perceived, that a slight error
in the atomic weight of carbon would be sufficient to explain the
discrepancies between calculation and direct analysis; an example
will immediately show this: 0°387 of naphthalin gave 1-318 of car-
bonic acid and 0°220 of water, which according to the atomic weight
attributed to carbon, would give 94°2 per cent. of carbon in naph-
thalin.

But on the supposition that the atomic weight of carbon should
be reduced to 38 instead of 38°6,[7. e. 6-08 hydrogen=1.] this ana-
lysis would be represented as follows :

Carbon (4i5.00.4..... 93°8
Hydrogen...... Pd

154 Intelligence and Miscellaneous Articles.

And if reduced to 100 parts according to the formula C*° H'*, ac-
cording to this new atomic weight, we should have

0 1520°0 .... 93°8
TELA) Sree Er tht ROOD pe. eI eGee
1620- 100:

M. Dumas observes, that according to this hypothesis, the old
formula for napththalin will remain correct, the atomic weight of
carbon, inferred from the density of carbonic acid and that of oxygen
gas, would however be incorrect.

It will be remembered by chemists, that some years since Ber-
zelius represented the atomic weight of carbon by 75°33, which,
from the results obtained in the analyses of organic substances, he
raised to 76°52. More lately a fresh modification has brought it to
76°44, which is the number adopted by many chemists. It is im-
possible, observes M. Dumas, according to the analysis of naphthalin,
that this last atomic weight can be correct, unless it be supposed
that an error which much exceeds all probability can be attributed to
hydrogen, hence it would be equal to about one-sixth of its weight;
added to this, every thing indicates that there is no error in the
atomic weight of hydrogen. It follows, therefore, that the atomic
weight of carbon must be inaccurate; for 100 of naphthalin always
give 6°2 of hydrogen, and 94:9, or at least 94:2 of carbon, which
makes an excess of ;;45, and even of ;}45.

From these results will be seen the necessity of reducing the ato-
mic weight of carbon to 76°0, or even 75:9, which last appears to be
the most probable.—Journal de Pharmacie, vol. xxiv. p. 393.

[It will be observed that hydrogen =1, the atomic weight of
carbon will be 6°07, which comes very near to the number hypothe-
tically adopted by Dr. Prout, and admitted by Dr. Thomson, Dr.
Henry, Mr. Brande, and most English chemists.—R. P.]

COMPOSITION OF WAX.

It having been supposed that wax contained margaric acid and
peculiar compounds which were termed cerain and cerin, M. Hess
has undertaken a fresh examination of this substance ; he commenced
by treating yellow wax with cold «ther, which decolorises it in
great part, and divides it into very delicate small scales; these were
put in a filter and suffered to drain, and the coloured solution having
run through, a fresh quantity of zther was added. The wax which
remained undissolved by this second operation was separated, and
twice melted with water; it was then white, hard, brittle, and
melted at about 150° Fahr. Two analyses gave, :

Hydrogen... 13°21 13°22

Carbon..... 80°79 80°84

Oxygen. ... 6°00 5°94
100° 100°

The portion of wax dissolved by the first quantity of ether was
separated from it by distillation with water. This, the more soluble

Intelligence and Miscellaneous Articles. 155

portion of the wax, was yellow, had a strong smell of fresh wax, which
it resembled in every respect, and melted at nearly the same tempe-
rature. It was treated with a very small quantity of ether, to
remove a portion of its colouring matter, and afterwards fused and
analysed. It yielded,

Hydrogen. . . 13°16

Carbon... . . 80°57

Oxygen. ... 6°27 100°

M. Hess infers that from the similarity of these results that the
first portion dissolved by the xther is identical with the second
portion, and consequently that wax is a uniform substance containing
neither margaric acid, cerin, nor cerain.

It may be supposed that this conclusion is applicable only to
Russian wax ; but if we consider that M. de Saussure obtained a
similar result with bees-wax ; that M. Boussaingault obtained from
the wax of the Cerozylon andicola, after separating the resin,

Hydrogen...13°1 13°3
Carbon,y.).:.. B12) .8L-6
Oxygen. ... 57 51

100-0 100°

no doubt can exist as to the identity of wax obtained in different
places.
_M. Oppermann has analysed two other kinds of wax; Japan
wax yielded,

Hydrogen. . . 12°07

Carbon... . . 70°97

Oxygen. ... 16°96 100°

If it be admitted that the amount of hydrogen in this analysis is
incorrect to the same extent as that in bees-wax, which is a very
likely circumstance, arising from the errors of manipulation, the
hydrogen and the carbon will be found to be in the same proportions
in both; forC: H2=70°9: 11°57. In this wax, 100 parts of car-
buretted hydrogen are combined with 20°4 of oxygen, which is
rather more than 3} times that in bees-wax.

To Brazilian wax M. Oppermann assigns as the composition,

Hydrogen. . . 12°08

Carbon... . . 72°77

Oxygen. ... 15°80 100°
which agrees exactly with this mode of regarding the subjects, since
C: H®=72°87: 11°896, which differs from the number stated
within the limits of faults of manipulation; 100 parts of carburet of
hydrogen are found combined with 17-7 of oxygen, which is almost
identical with the result obtained by M. Hess by treatment with
nitric acid.

All the characters of this substance which M. Oppermann assigns
to this substance are confirmed by M. Hess ; it appears therefore to
him very probable that in these cases the same radical occurs in two
different degrees of oxidizement, and M. Hess remarks that it would
therefore be extremely interesting to acquire positive information

156 Intelligence and Miscellaneous Articles.

respecting the vegetables which produce the Japanese and Brazilian
wax, and as to the mode in which they are extracted ; it may per-
haps be found whether this oxidizement depends on the nature of
the plant, or merely on that of the organ which produces the wax, or
on the time of collecting it.—L’Institut, No. 259.

AMILEN. OIL OF POTATOES.

M. Auguste Cahours on considering the numbers derived from the
composition and density of the vapour of this oil, was induced to
believe that it is a true alcohol, isomorphous [isomeric ?] with com-
mon alcohol, pyroxilic spirit and ethal: he therefore undertook a
series of experiments to verify these hypotheses ; and he conceives
that the oil of potatoes, and the compounds derived from it, contain
a radical C+0 H1*, which may be readily separated, and to which he
gives the name of Amilen.

When oil of potatoes is repeatedly distilled with anhydrous phos-
phoric acid, a colourless, oily, very limpid liquid is obtained, which
boils at about 320° Fahr.; this is shown by analysis to be a true
carburetted hydrogen, of the same composition as olefiant gas and
methylen, and differing from them only in the state of condensation
of its elements. The numbers deduced from analysis, and the de-
termination of the density of its vapour, give C?° H*° as its natural
formula, which represent four volumes of vapour. It therefore pre-
sents an anomaly which does not attend either olefiant gas or me-
thylen; and whilst in the alcohols which correspond to these car-
burets, four volumes of vapour are formed of four volumes of vapour
of carburetted hydrogen, and four volumes of vapour of water, this
new alcohol contains only two volumes of vapour of carburetted hy-
drogen and four volumes of the vapour of water.—L’Jnsiitut,
No. 260.

ACTION OF CHLORIDE OF ZINC UPON ALCOHOL.

M. Dumas has read a report respecting the memoir of M. Masson
on the above subject. The author dissolves chloride of zinc in
alcohol, and subjects the mixture to distillation, receiving the products
in different portions. When the liquor boils, it yields at first alcohol ;
but when the point of ebullition is a little raised, and reaches about
284°, it yields sulphuric ether. Thus the chloride of zine acts
upon alcohol, exactly like concentrated sulphuric acid, and these two
substances occasion the production of ether precisely at the same
temperature. On continuing the process, an oil appears which per-
fectly recalls the characters of that known by the name of sweet oil
of wine. It forms at about 320° Fahr., that is to say, very nearly under
the same circumstances which occasion its formation when prepared
from sulphuric acid and alcohol. It is further observable that the
ther formed is accompanied with a certain quantity of water, and
the oil which distils with a considerable quantity. These pheno-
mena also attend the reaction of sulphuric acid upon alcohol; and
M. Masson has further ascertained that no bydrochloric acid is

* The original symbols are preserved unaltered.

Intelligence and Miscellaneous Articles. 157

formed. It is then proved, by these experiments, that chloride of
zinc acts like sulphuric acid itself; in fact the analogy between these
substances is so perfect, that M. Masson has been recommended to
examine whether some product analogous to sulphovinic acid is not
also formed.

The oil obtained by M. Masson was found by him to contain two
different products, which were separated by distillation. One of
them, and the most volatile, is the most hydroguretted liquid carburet
known ; it contains more hydrogen than olefiant gas, and is repre-
sented by C8 H®; it boils at about 85° to 105° Fahr. The other,
which is less volatile, contains less hydrogen than olefiant gas, and
is represented by C* H’, and boils at about 572° Fahr.

These results, combined with those by which M. Regnault has
shown that the sweet oil of wine absorbs oxygen, perfectly explain
why some chemists have obtained in their analysis more carbon than
olefiant gas contains ; and why others, on the contrary, have obtained
the same composition as olefiant gas itself.

The facts thus stated would have appeared sufficient to show that
the labours of M. Masson were of such a nature as to close the dis-
cussions relating to the sweet oil of wine. But a German chemist,
M. Marchand, has lately published some analyses of heavy oil of wine,
light oil of wine, and the crystals which it yields. His results agree
perfectly with those of M. Serullas, and consequently differ from
those of M. Masson.

On considering the circumstance that some chemists have ope-
rated on the oil obtained by sulphuric acid and alcohol, others upon
the oil of the sulphovinates, and that M. Masson procured his from
alcohol and chloride of zinc, it may be imagined that these oils
differ from each other, especially as M. Masson has never been able
to extract from his oil the crystals obtained by M. Serullas and M.
Marchand from theirs, and on the contrary that he has obtained a
very volatile product unknown to the chemists who preceded him:
M. Marchand has however procured during the distillation of the

sulphovinate a very volatile product which he has not yet analysed.
—L’ Institut, No. 261.

ACTION OF SPONGY PLATINA.

M. Kuhlmann has described several new reactions determined by
spongy platina. Among which are the following :

1st. Ammonia mixed with air on passing at a temperature of about
572° Fahr. over spongy platina is decomposed, and the azote which
it contains is completely converted into nitric acid b
with the oxygen of the air.

2nd. Cyanogen and air, under similar circumstances, occasion the
formation of nitric acid and carbonic acid.

3rd. Ammonia, when combined so as to form a salt, acts in the
same way as free ammonia.

4th. Free azote cannot in any case be combined with free oxygen,

but all the compounds of azote, under the influence of spongy pla-
tina, yield nitric acid.

y combining

158 Intelligence and Miscellaneous Articles.

5th. Nitrous and nitric oxides, hyponitric and nitric acids mixed
with a sufficient quantity of hydrogen, are converted into ammonia by
their contact with spongy platina, and frequently without even the as-
sistance of heat. The action is frequently so energetic that violent
explosion ensues. All the azote of these oxides or acids passes to
the state of ammonia, by combining with the hydrogen. An excess
of nitric acid gives nitrate of ammonia.

6th. Cyanogen and hydrogen give hydrocyanate of ammonia.

7th. Olefiant gas and excess of nitric oxide, when hot and passed
over spongy platina, produce carbonate and hydrocyanate of am-
monia and water.

8th. With nitric oxide and excess of the vapour of alcohol, there
are obtained under the same circumstances, the same compounds as
above, and olefiant gas and a deposit of carbon.

9th. Free azote could not be combined with free hydrogen, but all
the compounds of azote were converted into ammonia by hydrogen,
either free or carburetted.

10th. In the last-mentioned reactions the presence of carbon in
combination with azote or with hydrogen, occasions the formation
of hydrocyanic acid.

llth. All the gaseous or vaporizable metalloids, without any ex-
ception, combine with hydrogen under the influence of spongy pla-
tina.

12th. The vapours of nitric acid mixed with hydrogen are totally
converted into acetic «ether, and water, at a moderate temperature.

M. Kuhlmann remarks that when precipitated platina (noir de
platine) is substituted for spongy platina, the action is infinitely less
energetic in the greater number of cases, which is the reverse of what
might be expected. The precipitated platina has indeed no power in
producing nitric acid, and it is very weak in producing ammonia, and
it never becomes incandescent as happens with spongy platina ; but
in converting acetic acid into ether, the action of precipitated pla-
tina is on the contrary more quick, and produces it even at common
temperatures.

It has been subsequently remarked that Berzelius has before stated
that when nitric oxide is mixed with hydrogen gas, and the mixture
exposed to partly calcined spongy platina, water and ammonia are
gradually formed, on account of the union of the hydrogen with both
the elements of the nitric oxide.—TZraité de Chemie, ii. 438-44.
L’ Institut, No. 261—262.

ARCHITECTURAL SOCIETY.

Lectures on the Properties and Natural History of the Mineral
Substances employed in the Arts of Architecture and Sculpture ;
by E. W. Brayley, Jun., F.L.S., F.G.S., Corr. Mem. Roy. Geol.
Soc. of Cornwall, &c.

These lectures will be continued at the Apartments of the Archi-
tectural Society, 35, Lincoln’s Inn Fields, on the following evenings,
at 8 o'clock.

a iia L

;
~

»

hae

a

Meteorological Observations. 159

February 12th, 1839. On limestone and other substances afford-
ing materials for cements.

March 12th. On artificial substances employed as substitutes for
stone.

April 9th. On those physical and chemical properties of building
stones upon which their applications essentially depend.

FRENCH EXPEDITION OF DISCOVERY TO THE SOUTH POLAR SHAS,

This expedition, undertaken by the French Government under
the command of M. d’Urville, has completely failed. The vessels,
Astrolabe and Zélée, were not able to penetrate beyond the 64° south,
being fully 10° short of the parallel reached by Weddel. They were
stopped by a compact barrier of ice, and found the whole sea in the
latitude we have mentioned completely frozen.—Ann. Nat. Hist.,
No. XI. —_——_—-

CURIOUS HABIT OF EARTH-WORMS.

While staying at Whitley, near North Shields, Mr. Fryer pointed
out to me that the worms (Lumbrici), which are abundant on the south
side of his gravel walk, just under the shade of the tuft, where the
walks are seldom used, gather together in a head all the loose stones
within 6 or 8 inches of their hole, and heap them over its opening,
sometimes to a considerable height. The holes when the stones are
removed are large, and there are often also a few straws projecting
from them. Ido not recollect to have observed any similar habit in
the worm in the neighbourhood of London; they are probably a
different species.—J. E. Gray.—Ann. Nat. Hist.

METEOROLOGICAL OBSERVATIONS FOR DECEMBER 1838.

Chiswick.—Dec. 1. Clear: rain. 2. Fine : heavy showers, with strong wind
and thunder and lightning at night. %,4. Fine. 5. Drizzly. 6. Fine. 7.
Rain. 8. Clear: frosty. 9. Frosty and foggy. 10. Frosty: fine. 11—13.
Hazy. 14,15. Foggy in the mornings: fine. 16—J9. Hazy andcold. 20.
Frosty: fine. 21. Hazy. 22—24, Rain. 25. Veryclear. 26. Frosty:
heavy rain at night. 27. Clear. 28. Frosty. 29. Overcast: rain. 30. Rain.
31. Clear and fine.

Boston.— Dec. 1. Fine: rainr.m. 2 Fine: rainearly a.m. 3. Fine. 4.
Fine: rain early a.m. 5. Cloudy. 6. Fine. 7. Cloudy: rain early a.m.
8—10. Fine. 11—1S. Cloudy. 14—16. Fine. 17,18. Cloudy. 19. Cloudy:
rainr.M. 20,21. Cloudy. 22—24. Rain. 25. Fine: snow early a.m. : snow
pM. 26, Fine: rainr.m. 27,28. Fine. 29,30. Cloudy. 31. Fine.

Applegarth Manse, Dum/ries-shire.—Dec. 1. Dull and cloudy: wetr.m. 2.
Frequent showers. 9, Dulland cloudy: temperate. 4. Clearedup: very mild.
5. Clear sunshine. 6. Dull and cloudy: shower pm. 7. Generally clear :
shower y.m. 8. Fine day: frosty r.m. 9. Dry, but cloudy. 10. Cloudy and
moist. 11. Clear and frosty. 12, Thick fog a.m.: cleared: moist. 13. Cloudy
and raw. 14. Clear and sharp. 15. Dull and threatening. 16. Fog: cleared
upr.m. 17. Dulland cloudy. 18, Cloudy a.m., but cleared up. 19. Cloudy
and threatening: rain. 20, Raw after rain preceding evening. 21. Clear
and cold: wet rm. 22. Dry and cold, but threatening rain. 23. Dry: still
looking dull, 24. Dry a.m.: moistr.m. 25. Dry and clear: freezing r.m.
26. Wet and stormy till evening. 27. Frosty: ground very slippery. 28.
Frost a.m.: thawed r.a. 29, Clear, but still soft. 30, Wet and stormy all day.
$1. Showery and unsettled.

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THE
LONDON ano EDINBURGH

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

{THIRD SERIES.}

MARCH 1839.

XXVII. On the general Magnetic Relations and Characters
of the Metals: Additional Facts. By Prof. Faxapay.*

AN idea that the metals would be all magnetic if made ex-
tremely cold, as they are all non-magnetic if above a cer-
tain temperature, was put forth in March 1836+, and some
experiments were made, in which several were cooled as low as
—60° or —70° Fahr., but without acquiring magnetic powers.
It was afterwards noticed + that Berthier had said that be-
sides iron, cobalt, and nickel, manganese also possesses magnetic
JSorce beneath a certain degree of temperature, much below zero.
Having had last May the opportunity of working with
M. Thilorier’s beautiful apparatus for giving both the liquid
and the solid state to carbonic acid gas, 1 was anxious to
ascertain what the extremely low temperature procurable by
its means would effect with regard to the magnetic powers of
metals and other substances, especially with relation to man-
ganese and cobalt ; and not having seen any account of similar
trials, I send the results to the Philosophical Magazine (if it
please the Editors to insert them) as an appendix to the two
former notices.

The substances were cooled by immersion in the mixture
of ether and solid carbonic acid, and moved either by platina
wires attached to them, or by small wooden tongs, also cooled.
The temperature, according to Thilorier, would be about 112°
below 0° of Fahrenheit. ‘The test of magnetic power was a
double astatic needle, each of the two constituent needles be-

* Communicated by the Author. :
+ London and Edinb. Phil. Mag., vol. viii. p. 177.
t Ibid., vol. ix. p. 65.

Phil. Mag. 8. 3. Vol. 14. No. 88. Mar. 1839. M

162 On the general Magnetic Relations of the Metals.

ing small and powerful, so that the whole system was very
sensible to any substance capable of having magnetism in-
duced in it when brought near one of the four poles. Great
care was required and was taken to avoid the effect of the
downward current of air formed by the cooled body; very
thin plates of mica being interposed in the most important
cases.

The following metals gave no indications of any magnetic

power when thus cooled to —112° Fahr.

Antimony, Lead,
Arsenic, Mercury,
Bismuth, Palladium,
Cadmium, Platinum,
Chromium, Rhodium,
Cobalt, Silver,
Copper, Tin,

Gold, Zinc.

A piece of metallic manganese given to me by Mr. Everett
was very slightly magnetic and polar at common temperatures.
It was not more magnetic when cooled to the lowest degree.
Hence I believe the statement with regard to its acquiring
such powers under such circumstances to be inaccurate. Upon
very careful examination a trace of iron was found in the piece
of metal, and to that I think the magnetic property which it
possessed must be attributed.

I was very careful in ascertaining that pure cobalé did not
become magnetic at the very low temperature produced.

The native alloy of iridium and osmium, and also crystals
of titanium, were found to be slightly magnetic at common
temperatures; I believe because of the presence of iron in
them.* Being cooled to the lowest degree they did not pre-
sent any additional magnetic force, and therefore it may be
concluded that zridium, osmium, and titanium may be added
as non-magnetic metals to the list already given.

Carbon and the following metallic combinations were then
experimented upon in a similar manner, but all the results
were negative: not one of the bodies gave the least sign of
the acquirement of magnetic power by the cold applied.

1. Carbon. 7. Native oxide of tin.

2.. Hematite. 8. manganese.
3. Protoxide of lead. 9. Chloride of silver.

4 —-— antimony. 10. lead.

5. ————— bismuth. 11. Iodide ofmercury.

6. White arsenic. 12. Galena.

[* See Dr. Wollaston’s paper on this subject, Phil. Trans. 1823, Part IL.,
or Phil. Mag. First Series, vol. lxiii. p. 15, Eprr.]

a

Dr. Kane’s Notice on the Theory of the “Ethers. 163

13. Realgar. 18. Sulphuret of tin.

14, Orpiment. 19. —— bismuth.

15. Dense native cinnabar. 20. antimony.
16. Sulphuret of silver. 21. Protosul. iron crystallized.
17 — copper. 22. anhydrous.

The carbon was the dense hard kind obtained from gas
retorts; the substances 3. 4. 5.6. 9.10.11. and some of the
sulphurets had been first fused and solidified; and all the
bodies were taken in the most solid and dense state which
they could acquire.

It is perhaps superfluous to add, except in reference to ef-
fects which have been supposed by some to occur in northern
latitudes, that the iron and nickel did not appear to suffer
any abatement of their peculiar power when cooled to the very
lowest degree.

Royal Institution, Feb. 7, 1839.

XXVIII. Notice on the Theory of the /Ethers. By Roperr
Kane, M.D., Professor of Chemistry in Dublin.*

[N discussing the claims advanced by Robiquet and Bou-

tron, to the discovery of the important relations of amyg-
daline and oil of bitter almonds, Professor Liebig has intro-
duced my name in such a manner as to render a notice of it
upon my part unavoidable. Robiquet’s memoir and Liebig’s
criticism on it are in the Annalen der Pharmacie for February
1838, which, however, did not reach Dublin until October,
and the passage in question (page 195) is as follows:

«“ Es kommt mir gerade so vor, als wenn Hr. Kane, Ber-
zelius gegeniiber, behaupten wollte, er sey der Entdecker
der Aethyl-theorie, die ihm abgeschmackter-weise von einigen
seiner Landsleute zugeschrieben wird, weil er einmal die Idee
hatte, dass man den Aether auch wohl als ein Oxyd betrachten
kénne, eine Idee, die mit eben so viel Recht von Hrn. Dumas
und Boullay in Anspruch genommen wird. Ich wiindere
mich nur dariiber, dass er seine Anspriiche nicht ganz ehrlich
desavouirt ; denn wahrend des Kampfes hat er sich in den
hintersten Reihen gehalten, ja er ist so gar von der einen
Seite zur andern tibergegangen, und sicher denkt er nicht
daran, jetzt, wo der Sieg entschieden ist, sich die Lorbeeren
anzueignen.”

In order that the nature of the matter under consideration
may be intelligible to every person, I will attach a transla-
tion of the passage.

* Communicated by the Author.

M2

164 Dr. Kane’s Notice on the Theory of the Aithers.

*‘ It appears to me exactly as if Mr. Kane wished to assert,
in opposition to Berzelius, that he is the discoverer of the
Ethyl theory, which some of his countrymen, in an absurd
manner ascribe to him, because he at one time had the idea
that «ther might as well be considered as an oxide, an idea
which with just as much right has been laid claim to by
Dumas and Boullay. Iam only astonished that he has not
honourably, totally disavowed his claims, since during the
battle he has kept himself in the rearmost ranks, nay, he has
passed over from one side to the other; and certainly he
cannot think, now that the victory has been decided, to ap-
propriate the laurels to himself.”

In the observations which it is my duty to make, in order
to show the groundlessness and unreasonable nature of the
remarks of Professor Liebig, I am anxious that it should be
understood that I do not mean to enter into any personal or
recriminating discussion with a philosopher to whom I am
under so many obligations for the kindness and zeal with
which he directed my first studies in organic chemistry in his
laboratory at Giessen, and with whom I continue up to the
present day in constant and most friendly communication.
It is my duty to show that my theory of the ethereal combi-
nations was not merely an accidental idea or a vague point of
view, but that from the commencement, it possessed a com-
pleteness and accordance with facts, which the system of Ber-
zelius did not acquire until it had undergone an important
modification in the hands of Professor Liebig.

In January 1835 I published in the Dublin Journal of
Medical and Chemical Science a short paper, in which the
question of priority between Berzelius and myself was dis-
cussed and the exact nature and extent of my views fully
shown. Neither that paper nor the original notice of 1833
was ever copied into any English scientific journal, nor, that
I am aware of, into any foreign one. In 1836 I asked one of
the Editors of the Philosophical Magazine to notice it; but it
was not done, probably because the chemists in England did
not take much interest in such subjects at the time. Neither
Dr. Turner in his Elements of Chemistry, nor still later Dr.
Thomson in his Organic Chemistry, has made any refer-
ence to my memoir, although both giving the Ethyl theory,
and ascribing the discovery of it to Berzelius and Liebig; in
fact the only one of my countrymen who to my knowledge is
exposed to the charge of bad taste in alluding to my views, is
Mr. Richard Phillips, who in his translation of the London
Pharmacopeeia has noticed the priority of my paper, and has
consequently given me credit for it.

Dr. Kane’s Notice on the Theory of the ZEthers. 165

In place of entering afresh into the discussion of priority,
T would ask the Editors of the Philosophical Magazine to
print the following quotation, from the Dublin Journal of Me-
dical and Chemical Science, vol. ii. p. 348. January 1833.
My claim will then go before the chemical world, which it
has never yet done; it can be judged of fairly, and I shall be
quite satisfied to abide by their decision; but my disavowing
the discovery of what Liebig himself calls one of the most
important theories in chemistry, when I believe the facts to
be most positively on my side, would certainly be much less
honourable than the course which Liebig blames me for
having adopted.

The idea of Dumas and Boullay to which Liebig alludes,
was simply that zther itself might be looked upon as a base.
So may the vegetable alkalies: but neither Liebig nor any
other chemist would think of generalizing the ethyl theory,
and, in the present state of science, considering morphia,
strychnia, quinia, &c. as oxides of peculiar radicals. Con-
sequently Dumas’s idea did not contain even the germ of the
ethyl theory; whilst I brought forward that theory more
completely formed, even than Berzelius did. No person can
respect more profoundly the extent and accuracy of view
which has throughout his long career so much distinguished
the Swedish chemist than I do; I seek not to diminish his merit
in proposing, nor that of Liebig in improving, the theory
which is now made the subject of dispute. I never called in
question or ever doubted of the perfect originality and inde-
pendence of his views ; but that the theory was original with
me, that in time my memoir preceded that of Berzelius, and
that my views were the same as those now held by Liebig and
Berzelius, are matters of fact which I could not disavow with-
out being guilty of a falsehood.

Liebig’s remark, that during the battle I have kept in the
rearmost ranks, requires from me a few words of explanation.
In the first place, I have no abstract love for fighting, parti-
cularly when it must be amongst friends, who, whatever they
may become less, are never more friendly after than they were
before it. My memoirs were published; I left them to sink
or swim, the opinions to be adopted or not, accordingly as
time and examination should test their value. Perhaps I was
wrong in not making more noise about my theory, but at that
time my speculations about the zthers were as regularly a
subject of amusement and ridicule among the chemical circles
in Dublin as my analyses of white precipitate were a year or
two ago, and as my theory of the ammoniacal combinations
is now; so I contented myself with setting my little skiff afloat

166 Dr. Kane’s Notice on the Theory of the Aithers.

and taking my chance for the rest. In fact, I still think the
matter of very little importance; and were it not that my si-
lence might be wrongly interpreted by evil-minded persons,
of whom this world does contain a few, I should have been
content to see without a murmur the ethyl theory ascribed to
Berzelius as long as it remains in chemistry, which I am very
much disposed to think will not be long; as yet, however, it
is the best we have.

Setting out from the ammonium theory of Berzelius, I de-
veloped the theory of the ethers, assuming ethereum (ethyl)
as a compound radical. Three years’ continued labour at the
ammoniacal combinations have given me a view of their na-
ture, which I hope the Royal Irish Academy will soon have
printed. In the mean time abstracts of my numerical results
and of my views have been published in the Proceedings of
the Academy.* This ammonia-theory modifying my views of
the nature of compound radicals, made me reconsider the
views of the ethereal combinations, and I declared myself to
Liebig when he was in Dublin as undecided about the con-
stitution of the zthers; and being disposed to consider my
results about the ammoniacal combinations as likely to affect
considerably the existing theories of the ethers, I recollect
perfectly an expression which, though trivial, perhaps Liebig
himself may yet bear in mind. I said to him, that I had dis-
carded all zther theories, and that my ideas about them were
all mashed up together. He said, Let them ferment and we
shall see what will come out of it. This was trifling talk,
but it will be seen that his observation that I had gone from
one side to the other is by means of these facts deprived of
the force which, in an evil point of view, it might at first sight
be supposed to possess.

With regard to the laurels, I have also a word to say.
There are two very different, but both important phases in
the history of the ethyl theory; the first its proposition,
the second its (pro tanto) establishment. Anything in the
way of a leaf for the first, I would certainly lay claim to
equally with Berzelius ; but for the second, to which I consider
the greater part of the branch should be devoted, no person
can dispute Liebig’s right. When I proposed the theory,
I did so from an examination of the results of others. I had
then never made an organic analysis; I never made an or-
ganic analysis until Liebig showed me how in Giessen.
Neither did Berzelius deduce the theory from his own ob-
servations: the analyses by Magnus, by Liebig, and by Mar-

[* Some of Prof. Kane’s results on the ammoniacal combinations will
be found in L. & E. Phil. Mag. vol. xiii, p. 156, Eprr.]

Dr. Kane’s Notice on the Theory of the ZEthers.. 167

chand gave Berzelius the materials: I am sure, if neither
Berzelius nor myself had in that year proposed the theory,
Liebig or somebody else would have done it in the next; sci-
ence was ripe for it, and it could not have been left undone.

Since the proposition of the theory by Berzelius and my-
self, the field has been left in Liebig’s possession almost com-
pletely ; he has fully established the superiority of the ethyl
theory over the old views of Dumas and Boullay, and has
shown that in the present state of science it alone fulfils the
conditions of a sufficient theory. But what is the present
state of science? I believed in the sufficiency of the ammo-
nium theory three years ago, and proposed the ethyl theory
after its model. I have satisfied myself that we can have in the
present state of science a theory still better than the ammo-
nium one of Berzelius for the compounds of ammonia, and
I hope that science will advance so rapidly as to render very
soon the ethyl theory insufficient; and I have myself only
refrained from a full examination of the zethereal compounds
with reference to applying to them the principles of my theory
of ammonia, because I am anxious to devote more time to a
subject of so much importance than I have at present at my
own disposal. I have already written to Professor Liebig,
and he has printed a few words on the change which my
views of ammonia may make in the theory of the «thers, and
I shall proceed to their development as soon as ever I can
find time.

“© Theory of the Athers*.

«¢ Dumas and Boullay had determined that in the ethers
the carburetted hydrogen might be regarded as a base similar
to ammonia; they even contrasted in a table its properties to
those of ammonia, and showed that in all the important cha-
racteristics it was equally marked, and that but for the acci-
dental circumstance of its insolubility in water, its alkaline
nature should have been long since recognised. Having de-
voted some attention to the ammonium theory of Berzelius, in
which he regards an atom of hydrogen as converting the am-
monia into a substance possessing many properties in com-
mon with the metals, [ was induced to try whether the same
simplicity of arrangement and classification which was given
to the ammonia compounds by that hypothesis, could not be
afforded to the different combinations of the ethers by the
assumption of similar principles. Let us consider the base

* Dublin Journal of Medical and Chemical Science, vol. ii. p. 348.

168 Dr. Kane’s Notice on the Theory of the Aithers.

of the zxthers as being, not olefiant gas, but, as Thomson
proposed, the isomeric liquid, whose formula is (4 C+4 H) 5
denote by the name of ethereum the hypothetic body formed
by its union with an atom of hydrogen, (as Berzelius terms
the compound of ammonia + an atom of hydrogen, ammo-
nium ;) and see the expressions for the composition of some

of the most interesting of these bodies.
Sulphuric zther (oxide of zthereum) = (4C+4H)+H+0.

Alcohol (hydrated oxide of zthereum) = (4C+4H)+H
+0O+H.

Muriatic zether (chloride of athereum) = (4C + 4H)+ (H
+ Ch.)

Hydriodic ether (iodide of zthereum) = (4 C+4H)+(H
+I.)

oe

Nitrous ether (hypo-nitrite of oxide of ethereum) = N
+ (4C+4H)+ (H+ O).

Oxalic zether (oxalate of oxide of xthereum) + 2C+(4C
+4H) +(H+0).

“‘ Any one conversant with the subject will at once see how
simply the above view accounts for the varied decompositions
which occur in the production of these different bodies. I
regret that the necessary brevity of this note prevents me from
illustrating any instance in detail, for it would facilitate very
much the comprehension of the subject. It is at once appa-
rent that the different oxy-combinations of zthereum have
been well studied, and that it is very probable that corre-
sponding chlorine, iodine, &c., compounds exist, a few of
which, as muriatic, hydriodic, and hydro-sulphocyanic ethers,
are already known. I had intended to enter into the deve-
lopment of this subject myself, but want of time prevented
me; the only experiments I made on it are a few, which I shall
subsequently relate. I now bring the subject forward in or-
der to direct the attention of those persons who are interested
in the progress of chemical philosophy to it, that its truth or
falsity may be, if possible, proved.”

[169 J

XXIX. Researches in the Undulatory Theory of Light, con-
tinued ; on the Elliptical Polarization produced by Quartz.
Part \. By J. Tovey, Esq.

To the Editors of the Philosophical Magazine and Journal.
GENTLEMEN,

T the conclusion of my paper on the Cause of the Ellip-
tical Polarization of Light, (L. and E. Phil. Mag., vol.
xii. p. 10,) I stated that I intended to apply my formule to
the case of this phanomenon produced by quartz crystal.
The fulfilment of this intention has been long delayed; but
I now proceed to the subject.
In the first place it is needful to put the last four of the
expressions (3.), of the paper referred to, into a more con-
venient form, thus: by the rules of trigonometry,

1— coskAuv = verskAz,

and

cos (k Aw—b) — cos b = —cos b vers k A'x +sinbsink Az,
cos (k Ax+b) — cos b = — cosh versk Ax — sinbsnkAx,
sin (kAa—b) +sinb=-+sindbverst Ax+cosbsnkAz,
sin (4 A2+6) — sind = —sin dverskAax + cosbsinkAz;

hence if we put
mS.v(r) AyAzverskAxr =
mX.v(r)AyAz sn kAxv=o',

the expressions referred to will become

(10.)

—g¢ cos 6 + o' sin b ='s,,

—¢ cos) — o' sin b =)5,,
/ C pe es (11.)

o cossb+casinb=sz3,

co cosb—cosinb=s's.
Now the third and fourth pf the equations (4.)* give
s,s!, = $3 8’3; hence s,s’, = o!? cos? b/—o° sin’ 6, and therefore

U 2
cos b= ta/ ey ae, (12.)
o”~ + o*

The third of the equations (4.), and the value of s’, in (11.)
give tes S;

p= ~ cos b — oa sin b* (12:)

Let cos 6 and —cos b denote the two values of cos 6 given

by (12.); these values will afford, by (13.), two correspond-

ing values of ¢, which denote by g, and g,. Now either pair

of these values satisfies the conditions of the problem; hence

* The equations numbered from (1,) to (9.) inclusive, are in the former
paper.

170 Mr. Tovey on the Elliptical Polarization

the first and second of the equations (4.) give, by taking the
values of Ss, s'o, from (11.) ;

n? + s—p,(o cosb+o! sin 6) = 0,

n? +s +p,(¢ cos b —o! sin b= 0

wap lbeeg la a Bard 3,5 220 (14.)
Pi :

neg ep TOPE TS Bey
2

because the sign of the sine of an arc remains the same while
that of the cosine changes.
For the sake of abridgement put

o(7) + ¥(r) AY =P;

o(r) + ¥(r) AY =P» (15.)
v (r) AyAZ =>
mx .pAwt =A; ms. p At =
> x.pA®=A, 7% pis = Aj;
m m
33 x.pAad= Ags gg 2:PAw = Ay,
m m ’
eraaae pAdt=As, wie p Ast = AZ,
&e. Xe. (16.)

|=
M
KQ

>
5
|

&

Then, since

3 =
sin kKAv = kAv — Lipa

2.3

+ &c.,

k? Ax? k*A a4
cos kAxw = 1 — 3 + copula &c. 5

vers kAu = 1—coskAz,

the formule (3) and (10.) give

— A, + Agk* — &e.

—A/i? + Akt — &e.

Ak —A,k + &e. (17.)
3 = Atk — AJ + &e,

¢ = Be — Bi + &e. 4

o = Bk —B, + &e

ll I ll

of Light produced by Quarts. 171

Before we proceed further we must make a few observa-
tions on the nature and relative magnitudes of the quantities
contained in the formule (17.) The capital letters denote
quantities depending entirely on the nature of the medium;
and by examining (15.) and (16.) we may see that A, and A,
are sums of which the terms are all positive ; but we infer that
the latter is almost indefinitely smaller than the former, be-
cause it involves a power of A z higher by two units, and A x
can never exceed the radius of the sphere of influence of a
molecule of the medium. ‘The same observations apply to
Aj and A’,;. The quantities A, A,, ... A’, A, ...B, B, B,,
... are sums in each of which the terms must be about half
of them positive and half negative, hence these quantities
must be comparatively small, and their real magnitudes can
be learnt only by comparing with experiments the results of
the calculation, the basis of which must originally be hypo-
thetical.

The sum B,, which is the principal quantity in the value
of c, is the sum which we have shown in art. 18, p. 426, vol.
ix. can always be made to vanish, by taking the axes of y and
zin proper directions. Let us suppose this done, and that
the other sums in o are indefinitely small in comparison with
A,, A/. Let us also suppose Ls to be insensible. Then, by
substituting the values (17.) in the equation (14.), writing v
for 2 transposing, and stopping at the terms explicitly ex-
pressed in (17.), we get

v? = A,—A,k?—e, sin 6.B,k,5
= AGATE? sin 6. B, k,

v2 = A,—A,h2—p, sin b. By ky (18.)

sin b. B, k.
= A/—Al, k? + ea 2 2
where we have marked v and & with subscript figures, be-
cause the values of these quantities must necessarily be dif-
ferent in the two equations, while that of x remains the same.
Suppose o*, and ¢ sin 4, to be indefinitely small in compa-
rison with the quantities to which they are joined in (12.) and

(13.), then Py
cos b = ra t+; (19.)

om
§

and 1 (20.)

P = ~ Slcos 6°

172 Mr. Tovey on the Elliptical Polarization
hence, if we suppose s, = s’,, the two values of p will be p,

‘ : 5s}
= — land p, = 1; and, assuming “a 1+. to be a very

Ce

small quantity, we shall have sin d = 1 and 6 = i nearly.

: 2 :
Now, since k = ~*, where A is the length of a wave, if

these values be substituted in (18.), and the terms involving
A;, A';, be comparatively insensible, there will result

Qn

on Ae B, Wed
% (21.)
a ann,
2
Sj n ay 20 h :
ince > =v, and k = ——, the expressions (2.) may
be changed to

: 2
7 = a sin {27 we—ayh,

¢ = pasin {A we- ath.

Now either of the values of v, and the corresponding value
of y, may be substituted for vand ¢ in these expressions. But
since the equations (1.) are of the first degree, they may be
satisfied not only by the values of y and ¢ corresponding to
each value of v, but by taking for y and ¢ the sums of these
particular values, in which we may change the value of a
as v changes. Hence the equations (1.) may be satisfied by

. Qu : : 25 ,
=a, sing Fai 1-2) b + a, sin{ $7 (0,t—2) } (22.)
| Qa : Qa
t= pa, sing 5 (v,t—2)— | + po Aq sind *(og—2)—0}.
i 2 ,

If in these expressions we give to p,, p., and 4, the values

just assigned to them, namely, —1, 1, and = , we shall have

Q
4 Nd, sind (t—a)b +a, sin { 3 (ty¢—a) }
ni Fe
f=—¢4, cos { = (v i—a)\ + dg COS {52 (mt—a) }
A; Ag

Now suppose a quartz crystal to have two parallel faces
perpendicular to its axis. Take « in the direction of the

"(23.)

of Light produced by Quartz. 173

axis; and conceive a ray of light, polarized in a given plane,
to fall on the crystal in the direction of x; causing a vibra-
tion of the molecules situated in the surface of the crystal,
which may be represented by

C

“vt: (24.)

where A and v are the length and velocity of the waves in the
incident ray.

Suppose the origin of x to be at the surface of the crystal
on which the light falls : then, when x is zero, the expressions
(23.) must coincide with (24.), which they will do if we make,

y= asin.

Gia ig eS hgs? Ne ern ee (25.)

Let ¢ = / (y? + ¢), then ¢ is the actual displacement of a
molecule within the crystal; and if we denote by « the angle
which < makes with y, then

4

tan 4 = ——35

therefore, since a, = a,, the expressions (23.) give

20 Bae this
cos. -— (v,¢—x) — cos. 5 (v, £—x)

tan ae = Z 3
sin. — (v,¢—x#)-+ sin. ks (v, £—x)
pu a
1 1
= tan. 20x (— — rm
1
and hence ict an (= vi, a ;
a, Ag
Now the equations (21.) give us
B, =
RAR 18 2s Bac
Ba iit aka
Peer e (26.)
Up = A?— : ie 3
. 2 Vo
nearly: therefore, since ais aE find
1 2
Af, Bet . At Byclle
A bist eR MEAP 0k Bog ANG i
1 B ] 1
hence ai SE es Day A 9 Ble 5
i Ag . ai, | r, Ye. Ae: )
= —2r po al » nearly ;

174 Dr. Winn on a remarkable Property of

which gives
5B hear
‘AZ "2 4 (27.)
From this result we learn, 1st, that since « is the same for
all values of ¢, every molecule vibrates to and fro in a straight

a= —477

line; 2nd, that « varies as xr? that is, directly as the thick-

ness of the crystal through which the ray has passed, and in-
versely as the square of the length of the wave.

These results are equivalent to the well-known experi-
mental laws of Biot; hence we conclude that our formulze
(23.), (25.), (26.), (27.), represent correctly the motions which
constitute a ray of light passing through the crystal in the
direction of its axis.

On looking at the length of this paper I think it will be
best to reserve the remainder of the investigation for another.

I am, Gentlemen, yours, &c.
Littlemoor, Clitheroe, Jan. 9, 1839. Joun Tovey.
P.S. In the paper, vol. xii. p. 11, line 8, for $(r) read
o(7) An; zbid. line 9, for $ (r) read $(r)Ag; and p. 12,
equations (7.) for p,,@,,(m,t—kx—b), read p,a, sin (nyt

—ka—b). The corrections of a few other errors in the same
paper have been previously given.

XXX. Ona remarkable Property of Arteries considered as
a Cause of Animal Heat. By J. M. Winn, M.D.*

Axout three years since whilst making a few experiments
with caoutchouc, I was forcibly struck with the property
it possesses of evolving heat when suddenly stretched, and
was led at the time to. infer the probability of other bade
being similarly endowed. The elastic coat of arteries espe-
cially, from the mechanical resemblance it bears to caout-
chouc, appeared to be one of the substances most likely to
exhibit this calefactory principle ; and in the event of this be-
ing the case it would not be unreasonable to conclude that
the incessant contractions and dilatations of the arteries du-
ring life must prove an efficient source of animal heat.
During the past week I was induced to resume the subject
afresh, and upon making an experiment with part of the
aorta ff a bullock, I felt much gratification in being able
to verify my previous conjecture. ‘The experiment was per-

* Communicated by the Author.

Arteries considered as a Cause of Animal Heat. 175

formed in the following manner. Having cut off a circular
portion of the descending arch of the aorta, about an inch
in length, I laid it open and carefully dissected out the ela-
stic coat, and taking hold of it by each extremity, I pulled
it to and fro with a continuous jerking motion (in imitation
of the systole and diastole of the artery) for the space of about
a minute, when placing it upon the bulb of a thermometer, I
had the satisfaction to find that after it had remained two
minutes the mercury had risen as many degrees. On re-
moving the thermometer the heat immediately began to di-
minish. ‘To be certain that the heat did not arise from any
other source than the one in question, I took the precaution of
covering my fingers with a double layer of flannel, to prevent
the communication of heat from the body: I also covered my
mouth with a handkerchief, to guard against the warm breath
affecting the thermometer, whilst watching the progress of the
experiment. I may likewise state that the experiment was
performed in a room without a fire, the temperature of the
air at the time being 55°. There were several difficulties to
contend with during the investigation, and it was not until
after repeated trials that the experiment succeeded to my satis-
faction. The chief impediment I think must have been
owing to the moisture of the artery, which by its evaporation
must have had a constant tendency to carry off the heat.
Having however performed the experiment twice consecu-
tively in the same satisfactory manner, I think there can be
but little doubt entertained as to its conclusiveness. My at-
tention was often arrested, whilst conducting the experiments,
by the striking mechanical analogies between caoutchouc and
the elastic coat of arteries. Like the latter it could be elong-
ated to twice its ordinary length, and, on withdrawing the
tension, would return to its usual dimension with considerable
force and a snapping noise. I was also surprised to find, on
slightly drying it, that it would erase black-lead pencil marks
from paper without leaving a stain. This latter circumstance
is perhaps of trifling importance; it serves however to show
that strong mechanical resemblance may exist between bodies
widely differing in their chemical properties.

From the foregoing observations I think I am entitled to
conclude that the whole of the heat developed in the animal
economy can now be satisfactorily explained. Physiologists
have often proved that the greater part of animal heat is oc-
casioned by the chemical changes which take place in the
lungs during respiration; there always remained however a
portion which could not be referred to that source, but which
can now I consider be fully accounted for by the mechanical

176 Dr. Winn on a remarkable Property of Arteries.

action of the arteries. The precise quantity of heat given
off during each beat of an artery, it would be exceedingly
difficult, perhaps impossible, to discover ; but if we admit the
development of only a very small quantity, it necessarily fol-
lows, from the circumstance of the action of the arteries being
in incessant operation during life, that the heat must quickly
accumulate to a great extent, and that the body unless cooled
by the functions of the skin and lungs, would in a short space
of time become preternaturally hot.

The following ‘physiological and pathological facts appear
to corroborate the view I have taken of the mechanical source
of heat. Ist, The minute distribution of the arteries to every
part of the system ensures a general and equal distribution
of heat. 2ndly, ‘The ossification of the arteries in old age, by
diminishing their elasticity, is a probable cause of the dimi-
nution of animal heat at the close of life. 3rdly, The in-
creased warmth of the body from exercise appears to be more
readily explicable upon the principle of increased force in the
arteries rather than that of increased vigour in the functions
of the lungs, in as much as the immediate effect of exercise is
evidently to embarrass the breathing, as skown by the hur-
ried respiration. 4thly. In many diseases of the lungs where
its functions are all at fault at a time when the arteries are
beating with increased violence, the heat of the body is found
to be above the usual standard. 5thly, Medicines which di-
minish the contractility and elasticity of the arteries almost
invariably reduce the heat of the body. 6thly, The heat of
local inflammations, in cases where the constitution does
not sympathize to any extent, cannot be easily referred to
any other source, as the arteries immediately in the neigh-
bourhood of the affected part are throbbing with yiolence at
a time when its capillaries (which are supposed to play so
large a share in the chemical theory of heat) are generally
considered to be entirely arrested. Many facts of a similar
nature could be enumerated, but enough I think have been
stated to establish the truth of the theory in question.

Of the nature of the mechanical force I have been investi-
gating little can be said; it may possibly be a kind of inter-
molecular friction. It is clearly, however, of a different na-
ture from ordinary friction, and which has also been consi-
dered a cause of animal heat; but I think erroneously so, for
on examining the mechanism of the human body we find that
everywhere the most efficient means of defence have been pro-
vided against its effects, as seen inthe various synovial, mucous,
and serous membranes, &c. It is not the province, however,
of the physiologist to speculate on the essential nature of me-

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On the Passage of the Moon across the Pleiades in 1839. 177

chanical or vital forces. His legitimate object in the present
state of the science would seem to be that of analysing the
simplest operations in the human body :--to aim first at dis-
covering the innumerable important processes that are carried
on through the influence of physical agents, before he pre-
sumes to explain the higher and more mysterious principle
of life: neither should he hastily call the vital power to his
aid, to explain a phenomenon, such as heat, that is known to
be common to every kind of matter, and which can be pro~
duced by a variety of physical forces totally independent of

life.
Truro, Nov. 8, 1838.

XXXI. On the Passage of the Moon across the Pleiades in
March, August, September, and November 1839. By the
Rev. James Groosy, F.#.A.S.

[With a Chart: Plate V.]
To the Editors of the Philosophical Magazine and Journal.

GENTLEMEN,

(THE annexed chart, showing the apparent path of the
moon’s centre over the Pleiades in the months of March,
August, September, and November of the present year, might
perhaps prove acceptable to some of your astronomical readers ;
but whether of sufficient importance to merit insertion in
your next Number, I must leave to your determination. The
occultation on the 19th of next month (March) will be par-
ticularly interesting ; happening when the moon is only four
days old, the whole of her disc will be visible ; and as the im-
mersions take place on the dark side, I have little doubt but
that by excluding the enlightened part from the field of view,
and using a telescope of considerable power, most, if not all,
the telescopic stars which suffer occultation may be perceived,
and their immersions observed. I should mention, that as
astronomical telescopes, generally used in these observations,
exhibit objects in an inverted order, the stars in the accom-
panying chart are inverted also, for the sake of more readily
comparing them with the appearance in the telescope. In
laying down the places of the stars, the right ascensions and
declinations, as well as the numbers annexed to them, are
taken from the catalogue of M. Jeaurat, as given by Mr.
Baily in the Philosophical Magazine for September 1822,
page 189, with the exception of No. 6, the declination of which
as there given appears to be about 1’ 15" too small. Mr. Baily
in projecting his chart has made the degrees of right ascension

Phil. Mag. S. 3. Vol. 14, No. 88. Mar.1839. N

178 On the Passage of the Moon across the Pleiades in 1889.

ard declination the same length; I have here used the pro-
portion of 55 to 60, which I believe is not far from the truth.
If a circle of paper 1,4, inch in diameter be passed across the
chart so that its centre may traverse the dotted line, it will
readily be seen what particular stars the moon will cover, as
well as the order in which they will disappear.

The Nautical Almanac gives the time of immersion, emer-
sion and near appulse of eight of the principal stars, at Green-
wich, as under :

At 8» 6™—No. 7 or 6 immerges.
9 —No. 6 or g immerges.
39 —No. 14 or c immerges.
44. —No. 10 or e immerges.
—No. 10 or e emerges.
4. —No. 7 or 6 emerges.
5 —No. 6 or g emerges.

9 near appulse of the moon’s southern limb to
No. 20 or d.

9 17 —No. 37 or » immerges.

9 28 —No. 14 or c emerges.

10 0 —No. 51 or # immerges, and No. 37 or 4
emerges.

10 17 near appulse of the moon’s southern limb to
No. 50 or f.

10 36 —No. 51 or 2 emerges.

Mr. Baily observes, that not only has the passage of the
moon across the Pleiades at all times attracted the attention
of astronomers, but that it is now more particularly interesting
as affording a favourable opportunity for illustrating the theory
of Cagnoli, with respect to his mode of determining the figure
of the earth by means of occultations of the fixed stars. To
which I will only add, that a more complete concurrence of
favourable circumstances for this purpose can hardly be hoped
for than that which the passage of the 19th of March pre-
sents. ‘The small portion of the moon’s disc which will be
illuminated, her high northern declination, and her path so
directed as to cover nearly the greatest number of stars possi-
ble, is a happy coincidence, which I am sorry to say we shall
not meet with in any of the other passages of this year, and
which, indeed, many years may pass before it occurs again.
Wishing that we may be favoured with the only remaining,
but most important desideratum, a cloudless sky,

I remain, Gentlemen, yours, &c,
Swindon, Feb. 8, 1839.

wmowommnn
on
~I

James GROoBY.

[o17e]

XXXII. Meteorological Observations during a Residence in
Colombia between the Years 1820 and 1830. By Colonel
Ricuarp Wrisut, Governor of the Province of Loxa,
Confidential Agent of the Republic of the Equator, Sc. Sc.

[Continued from p. 104.]
On the Method of Measuring Heights by Boiling Water.

‘os will be observed in the following Journal, that the indi-
cation of heights is, in most cases, joined with that of boil-
ing water. The former is in fact a deduction from the latter ;
I had but a confused idea of this method, till, upon my ar-
rival at Quito, I met with a pamphlet of the late D. Francisco
José Caldas (one of the most eminent victims sacrificed by
the barbarity of Murillo on taking possession of Bogota in
1816) published in 1819 at Bourdeaux, in which he details the
steps by which he arrived at a knowledge of this principle,
and the experiments by which he confirmed it. In the year
1801, during a scientific excursion in the neighbourhood of
Popayan, he happened to break his thermometer ; and in at-
tempting to mend it he was led to observe the variability of
the extremity of the scale corresponding to the heat of boiling
water. His reflections on this subject led him, after various
experiments, to the following conclusions: “ ‘The heat of boil-
ing water is in proportion to the atmospherical pressure: the
atmospherical pressure is in proportion to the height above
the level of the sea; the atmospherical pressure follows the
same law as the risings of the barometer, or, properly speaking,
the barometer shows nothing more than the atmospherical
pressure. Boiling water therefore shows it in the same man-
ner as the barometer. It can consequently show the eleva-
tion of places in the same manner, and as exactly as this in-
strument.” Ensayo de una memoria sobre un nuevo metodo
de medir las montanas, etc. p.10. His first experiment in
Popayan gave b. w. 75°7 of Reaumur, the height of the ba-
rometer being 22 in. 111. To find then the variation cor-
responding to one inch of the barometer:

gine —ggine 11)- — 5°] or 61 lines.
80°—75°7 = 4°°3, Then

4°°3 X12

61's, Paes ds 1D Tei 0°:8.
Then reversing the process
3 x 12
O78: Idk: 43:2 7 = Gt5 = Sit

180 Col. R. Wright’s Meteorological Observations in Colombia.

Difference betwixt this result and that of the barometer 34
lines. Satisfied with this commencement, or dawning of a
new theory, he began a series of experiments in the moun-
tains near Popayan, taking this city as the centre of his la-
bours, and fixing the elevation of the barometer at 22 11! 2,
and boiling water at 75°°65 of Reaumur.

At a spot named Las Juntas I made my first observation.
The barometer stood at 21' 9!, or 14! lower than at Popayan ;
the heat of boiling water was 74°°5 Reaumur. Then

Height of the barometer in Popayan 22' 11-2 B.W. 75°65
at Las Juntas 21 9 74°°50

2, 1°15
C oO.
122 = 14-2: 1915:: 12! ee = 0°971 of Reaumur
for 12! of the barometer.
I ascended to Paisbamba, a small farm five leagues south
of Popayan. Barometer 20! 9-1. BLW. 73°5.
Barometer in Popayan 22' 11!'2 B.W. 75°65

in Paisbamba 20 9°1 B.W. 73°50

Differences 2 2:1 2° 15
12 x2°1
Bet = Zoek 2 Bib: 312 wee = 0°'988 of Reaumur,

for 12 lines of the barometer.
I ascended ahill E. of Paisbamba called Sombreros. Baro-
meter 191, 65. B. W. 72°°4.
Barometer in Popayan 22' 11:20. B. W. 75°65
on Sombreros19 6°05. B. W. 72 *40

Differences 3 5°15. 3 °25
12X3°25
4Al‘15

I ascended the hill of Tambores: barometer18! 11'6. B.
W.. 71°75.
Barometer in Popayan 22) 11'2. B. W. 75°65
on Tambores 18 11°6. B. W. 71°75

Al*15 + 3°25:: = 0°947 for 12 lines barometer.

Differences 3 11°6 Ces) |
12x3°9
47°6
9°
Proof that above io of Reaumur is the true exponent of

ATG : 3°9::12 = 0'983 for 12! barometer.

one inch of the barometer.

On the method of measuring Heights by Boiling Water. 181

I then proceeded to take the observations of Las Juntas
and Sombreros, and calculating the exponent anew.

B. in Las Juntas 21 9 B. W. 74°60
in Sombreres 19 6:05 72°40
Differences 2 2°95 22
DEX DeD, ;
26:95 : 2°2::12 Weeds 0°:979 Reaumur for 12 lines of

the barometer.
B. in Paisbamba 20 9:1. B. W. 73°50

in Tambores 18 11°6. 71°75
Differences 1 9°5 1°75
DS a ey

1 Ota 175 25 12, —— = 0°976 of Reaumur

pe
for 12 lines of barometer.

The mean of the six quotients is 0°974, which may be as-
sumed as the exact exponent of 12 lines of the barometer.

Given then the heat of boiling water in any place to find the
corresponding elevation of the barometer, and consequently its
height above the sea.

As 0°:974: 12 lines, so is the difference of the heat of
B. W. To ascertain at Popayan the number of inches, lines,
&c. of the barometer. Ex. in Tambores, B. W. 71°15, to
find the corresponding height of the barometer.

B. W. in Popayan 75°65
in Tambores 71 *75

3:90

p39 KYA.) aching ata oras:

O97403 123: 7 Ok
As Tambores is above Popayan, deduct this quantity from
the height of the barometer in that city.
Bar. in Popayan 22 11°20
Deduct 4 00:05

Remain 18 11°15 ht. of bar. in Tambores.

Barometrical height observed 18 11:60
Do. by calculation of B.W. = 18 11°15

Difference 45
a result as exact as can be desired.
Upon this principle I calculated the elevation of the fol-
lowing 11 places:

182 Col. R. Wright’s Meteorological Observations in Colombia.

Popayan, Poblason,
Juntas, Buenavista,
Paisbamba, Hevradura,
Sombreros, Pasto,
Tambores, Quito.
Estrellas,

Memoria, &c. p. 13, et seq.

Working upon the foregoing principle, Caldas adapted to
his thermometer a barometrical scale. The product of 0°-974
of Reaumur by 19 is 18°506, or, in round numbers 18°5, i. e.
18°°5 of Reaumur correspond to 19 inches of the barometer.
Then measuring 18°5 from the summit, or 80° of Reaumur’s
scale, he transferred it to the opposite side of the thermome-
ter, dividing it into 19 equal parts, or inches of the barome-
ter, subdividing these by a nonius into 24 each = half a line
of the barometer. In this manner the elevation of the ther-
mometer by boiling water indicates the corresponding eleva-
tion of the barometer under the same atmospheric pressure.
Caldas observes that Humboldt, to whom he had communi-
cated these ideas, when they met in Popayan, objected the
variability of the heat of boiling water under the same atmo-
spherical pressure; to which he replies: ‘“* Long practice has
taught me its invariability in this respect, using the requisite
precautions in making the experiment: otherwise, how could
there be equal thermometers? Is not the invariability of the
heat of boiling water under the pressure of 28 inches the found-
ation of the superior term of all thermometrical scales? It
is true that boiling water does not zmmediately acquire its ex-
treme heat, but pushing the operation to its maximum its heat
is always the same.” p. 24.

Caldas did not consider an invariable exponent possible,
on account of the variability of atmospheric pressure. The
want, however, of a barometer induced me to make some ex-
periments to this effect, by way of rendering this method of
measuring elevations still more simple, and of more general
use. Is the variability of atmospheric pressure such as to
make any important difference in these calculations? Does
not water boil constantly at 212° at the level of the sea? At
Quito I found the same result as Caldas had several years
before; and several times the same result in this and other
parts of the Andes. The difference, then, is scarcely percep-
tible in the thermometer, and consequently unimportant in
the results of a calculation founded on the heat of boiling
water. The thermometer besides, immersed in boiling water,
is less liable to a variety of atmospheric influences to which
the mercury of the barometer is necessarily subject. Hence

On the method of measuring Heights by Boiling Water. 183

the great differences in different barometrical measurements
of the same elevations, and the differences observed betwixt
different thermometers exposed to the air in the same place,
which I have observed on comparing three together to
amount often to 14°, and never to less than 3°.

I took the following method to obtain an exponent of the
value in feet of each degree of the diminished temperature of
boiling water.

The elevation of Quito is, according to Boussingault,
9524; and water boils at 196°:25; 212°—196°25 = 155.
9524—-15'75=604 ft. 6 in. nearly. Neglecting the fraction as
unimportant, I assumed 604 feet for the value of the degree,
and began my observation on the conical hill of Javirac,
which backs the city, and is calcuiated at 729 feet in height.
Water boiled here by two thermometers at 195°. Then
196°25 ~ 195 = 1°25, difference of boiling water between
the hill and the city; and 1°25 x604 = 755 feet; difference
26 feet. I next ascended the volcano of Pichincha, and found
at the foot of the crater B. W. 186°. 212°—186° = 26° x 604
= 15’ 730 feet; and adding 246 feet, the difference between
this point and the summit, reckoned at 15°976. There could
be little error in the calculation. I next applied this formula
to the heights of several places calculated by Humboldt, and
where the heat of boiling water had been ascertained by
Caldas.

Thus Bogota, height according to Humboldt 8694 ft.

B. W. according to Caldas 197°6 sescorees 8712

Difference ...sseseeeee 18
Popayan, according to Humboldt «ss. 5823
{es Ww. 202°21 PTUeRT ICSI Cee 5922

Difference... ccccccess 99
Pasto, according to Humboldt ....cecseeeeees 8572
B. W. 197°6 eeeeeesesocetesaves eeeeesoeseeoeesseee 8712

140 ft.

The differences here are in four points 27 feet, 18, 99,
140. With respect to the hill of Javirac, commonly called
El Panecillo, 1 suppose the measurement to have been made
by the Academicians. But their calculations generally differ
from those of Humboldt, as in the case of Quito; the former
giving 9371 feet, the latter 9537; Pichincha 15,606 feet,
Humboldt 15,976; Chimborazo 20,583, Humboldt 21,414.
But even a difference of sites is sufficient to account for the
27 feet on ground so unequal as that of Quito. The 18 feet

184 Mr. T. Webster on the Colour of Steam.

in the height of Bogota is so trifling a difference, that it rather
proves the exactness of my calculation. In Popayan we have
99 feet; yet the different barometrical measurements of that
city differ still more widely. Caldas observes, p. 31, “ The
Baron de Humboldt’s barometer stood in Popayan at 23 3:4,
mine at 22 11:2, and Bouguer’s at 22 10°7.”. The most accu-
rate measurements of the peak of Teneriffe, selecting 4 out of
14, leave a difference of 71 French toises, or, rejecting the
barometric measurements of Borda, of 18 toises.— Humboldt,
Pers. Nar. v. 1, p. 160, 170. Saussure is said to have found
water boil at 187° on the summit of Mont Blanc, being, ac-
cording to Humboldt, 15,660. It is 90 feet only below the
point on Pichincha, where I found it to boil at 186°. The
elevations nearly equal the difference cannot amount to a de-
gree; and I consider the error less likely to be on my side,
because I was aware of the probable cause of error, and had
to deduce the height from the accuracy of the observation.
Humboldt in the same manner suspects the accuracy of La-
mouroux’s observation on the peak of Teneriffe.—P. Nar. vol.
1. p. 159.

[To be continued. |

XXXIII. A Letter to Professor Forbes on his communication
on the colour of Steam in the Philosophical Magazine of Feb.
1839. By Tuomas Wessterr, M.A., Sec. Inst. C. E.*

My Dear Sir,

jee me to address to you, through the medium of the
Philosophical Magazine, a few remarks on your most va-
luable observations on the colour of steam.

The conclusion to which you have been led, that the colours
of steam by transmitted lightare due to a particular stage of the
condensing process, appears to me likely to furnish informa-
tion on points with which we are at present totally unac-
quainted, and particularly with respect to the constitution of
steam, and the conversion of sensible into latent caloric, when
steam suddenly expands. We know that the hand may be
held in high pressure steam issuing from an orifice, and that
highly elastic steam allowed to expand into a partial vacuum
will instantly resume its original or liquid form, which phz-~
nomena are perfectly consistent with the general law of the
absorption of heat on the dilatation of bodies; but of the law
of the diminution of temperature consequent on this absorp-
tion we are totally ignorant. If the sum of the latent and
sensible heat be constant for steam of all elasticities, this con-

* Communicated by the Author.

Mr. T. Webster on the Colour of Steam. 185

version must be much more rapid for high than for low steam,
and consequently the stages of condensation must be passed
more rapidly in the former than in the latter case. I am not
aware of the existence of any authentic observations on the
temperature of highly elastic steam when expanded into a
partial vacuum, or at different distances from the orifice, nor
do I think that the thermometer will furnish the requisite
knowledge, as its changes are slow, and the changes to be as-
certained are exceedingly rapid, and unless noted at the in-
stant the numerous sources of inaccuracy will embarrass the
results. However, the thermometer will furnish no evidence
respecting the caloric of elasticity, as it has been termed, or
of the state of the particles in the progress of the steam to-
wards condensation. If these successions of colour are due
to the stage of condensation, they ought, on the preceding
principles, to succeed each other more rapidly, and the cri-
tical stage ought to appear nearer the orifice the higher the
elastic force of the steam. Thus I conceive your observations
on the colour of steam may be employed as a test of the truth
of the above principles, as a measure of the conversion of sen-
sible into latent caloric when steam suddenly expands, as a
means of obtaining some distinct and accurate knowledge of
the elasticity and temperature of steam during its expansion—
laws which cannot be ascertained by the mercurial column
and the thermometer, owing to the time which their indica-
tions require, and finally of the various transition states through
which the particles pass betwixt a colourless elastic and in-
elastic fluid.

Your experiments and observations, and the conclusions
which may be derived from them, are the only ones on which
I can rely with confidence, as supporting an opinion long en-
tertained by me respecting the theory of clouds. I have never
been able to assent to the theories generally circulated on this
subject, but have considered clouds as masses of vapour still
preserving its gaseous form, but in a different stage as regards
condensation from the surrounding vapour, and that while
their shape depends on the manner in which the transfer of
heat is going on, their colour depends on the state of transi-
tion in which the particles of the mass exist, and on the posi-
tion of the mass with respect to the illuminating body and the
spectator. ‘Thus their appearance will continue the same only
so long as the above conditions are unaltered, and a cloud
which appears stationary or in motion may in reality be a
mass of vapour in motion or at rest.

Should these brief remarks be of any value in themselves,
or turn the attention of any one to the important subject which

186 Mr. Cooper’s Remarks on Hydrocyanic Acid.

you have brought forward, I am sure you will excuse the li-
berty I have taken in thus addressing you.

Yours very truly,
25 Great George-street, Feb. 18, 1839. Tuomas WEBSTER.

XXXIV. Some remarks on Hydrocyanic Acid.
By J. T. Coorrr, Esq., Lecturer on Chemistry, Sc.*

| N the month of November 1831 I prepared some anhydrous
hydrocyanic acid, by passing a current of dry sulphuretted
hydrogen through a tube containing dry cyanide of mercury,
and condensed the product by a freezing mixture surrounding
the receivers; almost immediately after its preparation its
specific gravity was taken at the temperature of 37° Fahr.,
which was found to be 0°706; and in two hours and a half
after its preparation, I proceeded to determine its refractive
index, by inclosing a portion of the acid in a perfectly air-
tight hollow prism, whose refracting angle was 49° 15! 40",
which, adopting the notation of Sir J. F. W. Herschel, we
will call 2 I; then by a very simple instrument which I am
in the habit of using for these purposes, the angle D, or that
made by the incident and refracted ray, was found to be for
Frauenhofer’s ray A 14° 41’, and for ray H 15° 13! 30". Hence

Get)
by adopting Sir J. Herschel’s formula, viz. 4 = sin I

sin —
2
in which expression » represents the refractive index, we have
for ray A = = 7° 20! 30!
extreme red # = 24 37 50 log. sin. 9°61989
Jb gpl ae JD ;
| (ar 5) = 31 58 20 log. sin. 9°72387
= 1-2705 log. *10398
Temp. T° Dp
and for ray H 3 = 73645
; I :
extreme violet >= 24 37 50 log. sin. 9°61989
| i + =) = 32 14 35 log. sin. 9°72714
L py = 1°2801 log. 10725

* Communicated by the Author, from whom it was received in the course
of last month.—Enir.

Mr. Cooper’s Remarks on Hydrocyanic Acid. 187

pw for ray A = 1:2705 we for ray H = 1°2801
@ for ray H = 12801 w for ray A= 1°2705 wow

2)2°5506 oe = 0096 p—l
1°2753
= a = :0035 = p its dispersive power.

With a view of ascertaining whether any and what change
the acid so prepared would undergo in the course of time, it
was put into a stoppered phial, which had also a cap or cover
of glass fitted over the stopper, so as the more effectually to
secure the acid from evaporation, and the phial was then put
into a tin box to exclude it from the action of light; and so
carefully was this put aside, that I lost all trace of it until
a few weeks since, when upon re-examination, I found, that
to appearance, as far as I can remember the quantity the
phial contained, it has suffered no diminution in bulk, nor was
it perceptibly altered in appearance excepting a very minute
deposit of a light grey matter, which I believe to be lead de-
rived from the glass; and on retaking its specific gravity and
its refractive index, there was found to be no appreciable dif-
ference from the results formerly obtained in either.

The above facts go to prove that real hydrocyanic acid,
prepared by the above process, is capable of being preserved
for a length of time in close vessels if light be excluded; the
same portion of acid is now, and has been for more than a
fortnight, exposed to diffuse daylight, and as yet has shown no
signs of decomposition ; indeed, having frequently for the pur-
pose of demonstration had occasion to prepare the anhydrous
acid, I have remarked, contrary to the general opinion, that
the acid so prepared, under ordinary circumstances of keeping,
that is, of exposure to common daylight, that not one portion
in five or six undergoes any change by depositing the peculiar
brown matter, if the phials are perfectly well stopped. If the
stability of this acid should ultimately turn out to be different
from what is generally imagined, it is not improbable that in
consequence of its possessing so low a refractive index and
dispersive power, that it may be made available for some use-
ful optical purposes.

Now it has been stated by Dr. Brewster, that the refractive
index of cyanogen liquefied by pressure is 1°316; hence it is
possible, I conceive, to deduce, without the risk of incurring
any very considerable error, what the refractive index of hy-
drogen would be if it were possible to obtain that body in a
liquid state; for as hydrogen and cyanogen combine in equal
volumes to form hydrocyanic acid, and their union occurs in

188 Prof. Sylvester on the Motion and Rest of rigid Bodies.

the gaseous state without any condensation of volume, it may
be presumed that if we subtract the refractive index of hydro-
cyanic acid from that of cyanogen, viz. 275 from *316 = ‘041
for the refractive index of liquid hydrogen.

82 Blackfriars Road, London, Feb. 1, 1836.

XXXV. On the Motion and Rest of rigid Bodies. By
J. J. Sytvester, Professor of Natural Philosophy in Uni-
versity College, London.*

; heel the subjoined investigation, which, as far as I know, is

my own, I apply the same method to rigid as in a pre-
ceding paper I applied to fluid systems.

Let » yz be the coordinates of any particle in a rigid
body ;

? zy 2’ the coordinates of some other particle, and
lotion ar en yy +k Sis) eee T,

Call Aw, Ay, Az the increments which z, y, z receive
after the lapse of a small interval of time; so that terms in
which they enter in two or more dimensions may be neg-
lected.

dAx dAx dx
IN ce 3, pie tee b
Then A(#) = Ag+ ht kt Gath
= dby ,, day ,, day
A (y') = Ayt+ = ht iy + res a)

[AZ sy z
A (2) = Ae ee h+ Ske = 2+ BR.
P, Q, R containing binary and higher combinations of f, f, J,
which we shall have no occasion to express.

At the commencement of the interval the squared distance
of the two particles was (2’—2)*+ (y/—y)?+(s'—2)*; at the
end of the interval the distance squared is

(a!—2 + A(‘2)—Aa)'+ (y'—y +A (y)—Ay) + (=
LA (2)—Az)%
and these two expressions must be the same by the conditions
of rigidity whatever 4, /, and / may be; i.e.

Ax A NG 2
+42 = (4 at = i COD yeaah P)

dy dz
» SING bY ed Ny .
+ (e+ hich ge keh eal $Y

d 3

dAz dAz dA2 .
+ (04+ n+ recta T+ B)
for all values of 2, /, and J.

* Communicated by the Author.

Prof. Sylvester on the Motion and Rest of rigid Bodies. 189

Hence rejecting infinitesimals of the second order and

equating to zero separately the coefficients of h*, h°, 7, and of
kl, lk, hk, we have

dAk AA ae NE
er oo ae ane tie (@.)
dAy _ d Me dN ge
dy pre pee UT ee (<)
dAz CE Sa
7 Rahs (c) dy AAT se TNT OMRE (J)

By differentiating (d), (e), (f) with respect to 2,2, y re-
spectively, and substituting from (a), (4), (c), we obtain
ia ae GN © PAL
Wil ee eae | eee

By differentiating the same with respect to y, z, © respect-
ively, and proceeding as before, we have
Az pe Ar a PA z

ayy Bas) 4 dx? Tis
Thus, then, we have

ake + PAG _ Ax BiG

dz dy dz

dA Ay a)

Ha a “Ge = dat = 9

dAz | @Az_. @hz

aye dae dy’

« Ar=A+By+Cz (0.)
Ay=D+EHz+4+Fe (p.)
Az=G+Hae+Ky (q-)

A, B, C, D, E, F, being constant for a given instant of time ;

between which by virtue of the = "5 (d), (e), (f), we have
the relations

E+K=0 H+-C=0 B+F=0

If we call uw, v, w the three component velocities of the
particles at 2, y, parallel to the three axes, and X, Y, Z,
the three internal forces, it is at once seen that w, v, w, as

also A X, Y, A, Z, must be subject to the same equations as
limit Az, Ay, Az;

so thatw = a+yy — 62 (1) AX,=a,+y,y— 6,2 (A)
v = bt+az—year (2) AY, =)44,2—y2, (f)
w=ct+Pa—ay (3) AZ, =e4+Pr—ay (he)

190 Prof. Sylvester on the Motion and Rest of rigid Bodies.
Also if X, Y, Z be the impressed forces, we have

aks (4)
But Xisige (5)
Z,+ Tae (6).

And by Gauss’s principle, calling m the mass of the particle

at zy, 2, ASm.{X? + Y? — Z7?} = 0.
Hence equating separately to zero the coefficients of a, 5, ¢,
and of #, 8, y, inthe quantity 3m (X,AX,+ Y,Ay+ZAZ)

we have

Sm X, = 0

Na)

Mt Lj. 0

xm (Ly—Y,z) =0 kas
Xm.(Y,e2—X,y) = 0 |
Xm.(X,2—Z,x2) = 0 ‘I

Lastly, we have the = ™5

d e
ain ae (13)
_ dy
OS ae (14)
| a % r
n= at (15)

From the fifteen equations marked 1 to 15, the motion
may be determined by assigning the position of each particle
at the end of the time ¢ in terms of its three initial coordi-
nates, its three initial velocities, and the initial values of the

nine quantities.

XM @ MY z Sm x?
zm.y Mm 2x my?
2M .% SM xy xm x

In the case of rest X, = —X Y,=—Y Z,=—Z, and
the = "7 to 12 inclusively taken, express the conditions of
equilibrium.

The equations 0, p, g, which have been obtained from con-
ditions purely geometrical, establish the well-known but inter-
esting and not obvious fact, that any small motion of a rigid
body may be conceived as made up of a motion of translation
and a motion about one axis.

University College, London, Dec. 8, 1838. J. J. SYLVESTER.

poaPaak]

XXXVI. On the Colours of Mixed Plates. By Sir Davip
Brewster, K.G.H., F.R.S.*

(THE colours of mixed plates were discovered by Dr.

Thomas Young}, and described in the Philosophical
Transactions for 1802. He produced them by interposing
small portions of water, or butter, or tallow between two
plates of glass, or two object glasses pressed together so as to
give the ordinary colours of thin plates. In this way portions
or cavities of air were surrounded with water, butter, or tal-
low; and on looking through this combination of media he
saw fringes or rings of colour six times larger than those of
thin plates that would have been produced had air alone been
interposed between the glasses. These fringes or rings of
colour were seen by the direct light of a candle, and began
from a white centre like those produced by transmission; but
on the dark space next the edge of the plate, Dr. Young ob-
served another set of fringes or rings, complementary to the
first, and beginning from a black centre like those produced
by reflection. This last set of colours was always brighter
than the first.

The following is Dr. Young’s explanation of these two
series of colours.

** In order to understand,” says he, “ this circumstance,
we must consider that where a dark object is placed behind
the glasses, the whole of the light which comes to the eye is
either refracted through the edges of the drops, or reflected
from the internal surface; while the light which passes
through those parts which are on the side opposite to the
dark object consists of rays refracted as before through the
edges, or simply passing through the fluid. The respective
combinations of these portions of light exhibit a series
of colours of different orders, since the internal reflection
modifies the interference of the rays on the dark side of
the object, in the same manner as in the common colours of
thin plates seen by reflection. When no dark object is near,
both these series of colours are produced at once; and since
they are always of an opposite nature at any given thickness
of a plate, they neutralize each other and constitute white
light j.”

* From the Philosophical Transactions for 1838, p. 73.

+ Since this paper was written I find that this class of colours was dis-
covered by M. Mazeas, and that his experiments were repeated and varied
by M. Dutour.

¢ Philosophical Transactions, 1802. Dr. Young republished the same
explanation of mixed plates in 1807 in his Elements of Natural Philosophy.
See yol. i. pp. 470, 787 ; vol. ii. pp. 635, 680.

192 Sir D. Brewster on the Colours of Mixed Plates.

In so far as I know, these observations have not been re-
peated by any other philosopher; and subsequent authors
have only copied Dr. Young’s description of the phanomena
and acquiesced in his explanation of them. In taking up this
subject I never doubted the accuracy or the generality of the
results obtained by so distinguished a philosopher. I was
induced to study the phenomena of mixed plates as auxiliary
to a more general inquiry; and having observed new pheeno-
mena of colour in mineral bodies, which have the same origin
as those of mixed plates, and which lead to conclusions dif-
ferent from those of Dr. Young, I am anxious that they
should be described in the same work which contains his ori-
ginal observations.

Having experienced considerable difficulty in obtaining
satisfactory specimens of the colours of mifed plates by using
the substances employed by Dr. Young, I sought for a me-
thod of producing them which should be at once easy and
infallible in its effects. With this view I tried transparent
soap, and whipped cream, which gave tolerably good results ;
but I obtained the best effects by using the white of an egg
beat up into froth. To obtain a proper film of this substance
I place a small quantity between the two glasses, and having
pressed it out into a film I separate the glasses, and by, hold-

_ ing them near the fire I drive off a little of the superfluous
moisture. The two glasses are again placed in contact, and
when pressed together so as to produce the coloured fringes
or rings, they are then kept in their place either by screws or
by wax, and may be preserved for any length of time.

If we now examine with a magnifier of small power the
thin film of albumen, we shall find that it contains thousands
of cavities exactly resembling the strata of cavities which I
have described as occurring in topaz, quartz, sulphate of lime
and other minerals*; and if we look through the film at the
margin of the flame of a candle, we shall perceive the two
sets of colours described by Dr. Young, the one upon the lu-
minous edge of the flame, and the other on the dark space
contiguous to it. The first we shall call the dzrect, and the
second, which are always the brightest, the complementary

Sringes.

If we apply a higher magnifying power to the albuminous
films, and bring the edge of one of the cavities to the margin
of the flame, we shall perceive that both the direct and the
complementary colours are formed at the very edge, the com-
plementary ones appearing just when the direct ones haye
disappeared, by the withdrawal of the edge from the flame.

* Edin. Trans., vol, x. Part I. p. 407.

a

Sir D. Brewster on the Colours of Mixed Plates. 193

As the colours therefore are produced solely by the edges
of the cavities, their intensity must, ceteris paribus, depend
on the smallness of the cavities, or the number of edges which
occur in a given space. When we succeed in forming an
uniform film in which the cavities are like a number of minute
points, the phenomena are peculiarly splendid and we are en-
abled to study them with greater facility. When the edges of
these cavities are seen by an achromatic microscope, and in
direct light, neither the direct nor the complementary colours
are visible; but if we gradually withdraw the lens from the
cavities a series of beautiful pheenomena appear. When the
vision first becomes indistinct both the direct and the comple-
mentary colours appear at the same time, specks of the com-
plementary red alternating with brighter specks of the direct
green light. By increasing the distance of the lens from the
cavities, the complementary specks become less and less visi-
ble, and we see only the direct green light.

In order to study these phaznomena by observing the ac-
tion of a single edge upon light, and to ascertain the effect of
an edge when there were no prismatic edges to refract, and
no internal surface to reflect light, I conceived the idea of im-
mersing thin plates ofa solid substance in a fluid of such a re-
fractive power, that the thickness of the plates should be vir-
tually reduced to the same degree of thinness as the film of
albumen between the plates of glass. ‘The new substance de-
scribed by Mr. Horner*, and which I shall call nacrite, fur-
nished me with the means of performing this experiment. I
accordingly inclosed the thinnest films of it between two plates
of glass containing balsam of capivi; and I had the satisfac-
tion of observing that the bounding edge of the plate and the
fluid produced the identical direct and complementary colours
above described.

The bounding edge which I selected for observation gave a
bright green for the direct, and a bright red for the complement-
ary tint. This edge appeared as a narrow distinct black
line, exceedingly well defined, and of a uniform breadth like
the finest micrometer wire. It consequently obstructed the
incident light and produced the phznomena of diffracted
fringes. ‘Vhese fringes, however, were modified by the pe-
culiar circumstances under which they were produced, and
exhibited in their tints both the direct and complementary
colours under consideration.

When the diffracted fringes are viewed in candle-light by a

* Philosophical Transactions, 1836, p. 49. [or L. and E, Phil. Mag.,

vol. x. p. 201.
Phil. Mag. S. 3. Vol. 14, No. 88. Mar. 1839. Q

194 Sir D. Brewster on the Colours of Mixed Plates.

jens placed at a greater distance from the diffracting edge than
its principal focus, the middle of the system of fringes corre-
sponding to the diffracted shadow of a fibre is occupied with
the direct tint, which we shall suppose to be green; and on
each side of this green shadow, as we may call it, we observe
very faintly the complementary red tinging what are called the
two first exterior fringes. This tinge of red is strongest in the
first fringe within the solid edge, or within the green shadow,
while it is yellowish in the first fringe without the green sha-
dow. ‘These effects are inverted if we place the lens nearer
to the edge than its principal focus.

The phenomena now described appear more distinct if we
take an extremely narrow piece of nacrite, having its two edges
nearly in contact, and transmitting only a narrow line of light.
In this case the two red fringes within the solid edge unite
their tints, and become a bright red; and in like manner if
we place the lens nearer the solid edges than its principal fo-
cus, the two yellow fringes will unite their tints, and become a
brighter yellow band. In this last case, when the two bound-
ing edges are still nearer each other, the united fringes, in
place of being yellow, will be green, or the same as the direct
colour.

if we bring the edges of two pieces of nacrite of equal thick-
ness very near each other, having, as formerly, green for the
direct, and red for the complementary colour, the space between
the edges, or between the green bands, will be faint ved when
the lens is nearer the edges than its principal focus, and yel-
low when it is further from them; but if the edges are brought
still nearer, the faint red will become brighter, and the united
green bands will take the place of the yellow one.

Let us now return to our plate of acrite with a single edge,
having green and red for the two tints: and let us always sup-
pose that the lens is adjusted to observe the diffracted iringes,
that is, that the lens is placed at a greater distance from the
diffracting edge than its principal focus. We shall also sup-
pose that the light of the sun passing through a narrow aper-
ture parallel to the diffracting edge is substituted for the light
of a candle. Under these circumstances the central part of
the system of fringes seen by light incident perpendicularly,
consists of blue*, green, and yellow light, constituting, as it
were, the shadow of the edge, the blue light being on the
same side as the plate of nacrite, and the yellow rays encroach-
ing upon the exterior faint red band already described, the
other red band next the blue being more distinctly seen. If

* Owing to the small quantity of blue rays in candle-light the blue almost
disappears in it.

Sir D. Brewster on the Colours of Mixed Plates. 195

we now incline the incident ray to the plate of nacrite more
than 90°, the faint red band next the yellow gradually be-
comes brighter, while the other bands become fainter ; and at
the boundary of light and darkness all the other bands dis-
appear except this red one, which is the complementary colour
to the green, (produced by the union of the dlue, green and
yellow bands,) and the colour which is seen upon the dark
space next the edge of the flame, as described by Dr. Young.
If we, on the other hand, incline the incident ray in an oppo-
site direction, so that it forms with the plane of the plate a
less angle than 90°, the red band next the blue will now be-
come brighter; and at the boundary of light and darkness,
when all the other bands have disappeared, the ved band will
afford the complementary colour to the green.

As the edge of the plate of nacrite is rough and unpolished,
and accurately perpendicular to the parallel faces, there are
no reflected nor refracted pencils, whose combinations with
one another, or with the direct rays, can be employed to ac-
count for the complementary colours. The phaznomena of
mixed plates, indeed, are cases of diffraction when the light is
obstructed by the edge of very thin transparent plates placed
in a medium of different refractive power. If the plate were
opake, the fringes would be exactly those which have been so
often described, and explained by the principle of interference.
But owing to the ¢ransparency of the plate, fringes are pro-
duced within its shadow; and owing to the thinness of the
plate the light transmitted through it and retarded, interferes
with the partial waves which pass through the plate and with
those which pass beyond the diffracting edge with undimi-
nished velocity, and modifies the usual system of fringes in
the manner which we have described.

As the plate of nacrite diminishes in thickness, or as the fluid
in which it is immersed approaches to it in refractive density,
the central coloured bands, whose union constitutes the direct
tint, will diminish in number, and descending gradually in
the scale will finally disappear when the retardation produced
by the plate does not perceptibly alter the phase of the ray.
When the plate, on the other hand, increases in thickness, or
the fluid diminishes in refractive power, the central bands will
become closer and more numerous, and will finally resemble
the fringes within the shadow of the ordinary system.

When the plate of nacrite is thicker at one place than an-
other by the partial removal of a parallel film, the edge where
the increase of thickness takes place produces exactly the same
phenomena as the edge of the film that is removed, or of the
film that is elevated aboye - general surface, and hence we

2

196 Mr. Talbot’s Account of the

are led to look for the phenomena of mixed plates in mine-
rals, such as sulphute of lime and mica, where a plate of two
different thicknesses can be easily obtained. I have accord-
ingly discovered the phenomena of mixed plates distinctly
exhibited in sulphate of lime and mica.

A more splendid exhibition of these colours is seen when a
stratum of cavities of extreme thinness occurs in sulphate of
lime. I have observed such strata repeatedly in the gypsum
from Mont-martre ; but they are most beautiful when the stra-
tum has a circular form. In this case the cavities are exceed-
ingly thin at the circumference of the circle, and gradually
increase in depth towards the centre, so that we have a series
of edges increasing in thickness towards a centre; the very
reverse of a mixed plate, such as a film of albumen pressed
between two convex surfaces. The system of rings is there-
fore also reversed, the highest order of colours being in the
centre, while the lowest are at the circumference of the circu-
lar stratum. In many strata of cavities, such as the one which
I have engraven in my paper on the new fluids in minerals*,
the cavities are too deep to give the colours of mixed plates.

Another example of the colours of mixed plates in natural
bodies occurs in specimens of mica, through which titanium
is disseminated in beautiful flat dendritic crystals of various
degrees of opacity and transparency. In these specimens the
titanium is often disseminated in grains, forming an irregular
surface. ‘The edges of these grains, by retarding the light
which they transmit, produce the direct and complementary
colours of mixed plates in the most perfect manner, the tints
passing through two orders of colours as the grains of titanium
increase in size towards the interior of the irregular patch. I
have observed another example of these colours in the deep
cavities of topaz, from which the fluids have either escaped,
leaving one or both of the surfaces covered with minute parti-
cles of transparent matter, or in which the fluids have suffered
induration.

Allerly by Melrose, Oct. 18, 1837.

XXXVII. Some Account of the Art of Photogenic Drawing.
By H. ¥. Tarpor, Esq., £.2R.S.+

§ 1
[N the spring of 1834 I began to put in practice a method
which I had devised some time previously, for employing

* Edinburgh Transactions, vol. x. plate ii- fig. 33.
+ Read before the Royal Society on the 3lst of January, and communi-
cated by the Author.

Art of Photogenic Drawing. 197

to purposes of utility the very curious property which has
been long known to chemists to be possessed by the nitrate
of silver ; namely, its discoloration when exposed to the violet
rays of light. ‘This property appeared to me to be perhaps
capable of useful application in the following manner.

I proposed to spread on a sheet of paper a sufficient quan-
tity of the nitrate of silver, and then to set the paper in the
sunshine, having first placed before it some object casting a
well-defined shadow. ‘The light, acting on the rest of the
paper, would naturally blacken it, while the parts in shadow
would retain their whiteness. Thus I expected that a kind
of image or picture would be produced, resembling to a cer-
tain degree the object from which it was derived. I expected,
however, also, that it would be necessary to preserve such
images in a portfolio, and to view them only by candle-light ;
because if by daylight, the same natural process which form-
ed the images would destroy them, by blackening the rest of
the paper.

Such was my leading idea before it was enlarged and cor-
rected by experience. It was not until some time after, and
when | was in possession of several novel and curious results,
that I thought of inquiring whether this process had been
ever proposed or attempted before? I found that in fact it
had; but apparently not followed up to any extent, or with
much perseverance. ‘The few notices that I have been able
to meet with are vague and unsatisfactory; merely stating
that such a method exists of obtaining the outline of an ob-
ject, but going into no details respecting the best and most
advantageous manner of proceeding.

The only definite account of the matter which I have been
able to meet with, is contained in the first volume of the Jour-
nal of the Royal Institution, page 170, from which it appears
that the idea was originally started by Mr. Wedgwood, and
a numerous series of experiments made both by him and Sir
Humphry Davy, which however ended in failure. I will take
the liberty of quoting a few passages from this memoir.

“* The copy of a painting, immediately after being taken,
must be kept in an obscure place. It may indeed be ex-
amined in the shade, but in this case the exposure should be
only for a few minutes. No attempts that have been made to
prevent the uncoloured parts from being acted upon by light,
have as yet been successful. They have been covered with
a thin coating of fine varnish; but this has not destroyed their
susceptibility of becoming coloured. When the solar rays
are passed through a print and thrown upon prepared paper,

198 Mr. Talbot's Account of the

the unshaded parts are slowly copied; but the lights trans-
mitted by the shaded parts are seldom so definite as to form
a distinct resemblance of them by producing different inten-
sities af colour.

“* The images formed by means of a camera obscura have
been found to be too faint to produce, in any moderate time,
an effect upon the nitrate of silver. To.copy these images was
the first object of Mr. Wedgwood, but all his numerous ex-
periments proved unsuccessful.”

These are the observations of Sir Humphry Davy. I have
been informed by a scientific friend that this unfavourable re-
sult of Mr. Wedgwood’s and Sir Humphry Davy’s experiments,
was the chief cause which discouraged him from following
up with perseverance the idea which he had also entertained
of fixing the beautiful images of the camera obscura. And no
doubt, when so distinguished an experimenter as Sir Hum-
phry Davy announced “ that all experiments had proved un-
successful,” such a statement was calculated materially to dis-
courage further inquiry. ‘The circumstance also, announced
by Davy, that the paper on which these images were depicted
was liable to become entirely dark, and that nothing hitherto
tried would prevent it, would perhaps have induced me to
consider the attempt as hopeless, if I had not (fortunately)
before I read it, already discovered a method of overcoming
this difficulty, and of fxing the image in such a manner that
it is no more liable to injury or destruction.

In the course of my experiments directed to that end, I have
been astonished at the variety of effects which I have found pro-
duced by a very limited number of different processes when
combined in various ways; and also at the length of time
which sometimes elapses before the full effect of these mani-
fests itself with certainty. For I have found that images
formed in this manner, which have appeared in good preser-
vation at the end of twelve months from the time of their
formation, have nevertheless somewhat altered during the se-
cond year. This circumstance, added to the fact that the
first attempts which I made became indistinct in process; of
time (the paper growing wholly dark), induced me to watch
the progress of the change during some considerable time, as
I thought that perhaps all these images would ultimately be
found to fade away. I found, however, to my satisfaction,
that this was not the case; and having now kept a number of
these drawings during nearly five years without their suffering
any deterioration, I think myself authorized to draw conclu-
sions from my experiments with more certainty.

Art of Photogenic Drawing. 199
§ 2. Effect and Appearance of these Images.

The images obtained in this manner are themselves white,
but the ground upon which they display themselves is ya-
riously and pleasingly coloured.

Such is the variety of which the process is capable, that
by merely varying the proportions and some trifling details of
manipulation, any of the following colours are readily attain-
able :

Sky-blue, Brown, of various shades,

Yellow, Black.

Rose-colour,
Green alone is absent from the list, with the exception of a
dark shade of it, approaching to black. The blue-coloured
variety has a very pleasing effect, somewhat like that pro-
duced by the Wedgwood-ware, which has white figures on
a blue ground. ‘This variety also retains its colours perfectly
if preserved in a portfolio, and not being subject to any spon-
taneous change, requires no preserving process.

These different shades of colour are of course so many dif-
ferent chemical compounds, or mixtures of such, which che-
mists have not hitherto distinctly noticed.

§ 3. First Applications of this Process.
The first kind of objects which I attempted to copy by this

process were flowers and leaves, either fresh or selected from
my herbarium. ‘These it renders with the utmost truth and
fidelity, exhibiting even the venation of the leaves, the minute
hairs that clothe the plant, &c.

It is so natural to associate the idea of labour with great
complexity and elaborate detail of execution, that one is more
struck at seeing the thousand florets of an Agrostis depicted
with all its capillary branchlets (and so accurately, that none
of all this multitude shall want its little bivalve calyx, requiring
to be examined through a lens), than one is by the picture
of the large and simple leaf of an oak or a chestnut. But in
truth the difficulty is in both cases the same. The one of
these takes no more time to execute than the other; for the
object which would take the most skilful artist days or weeks
of Jabour to trace or to copy, is effected by the boundless
powers of natural chemistry in the space of a few seconds,

To give an idea of the degree of accuracy with which some
objects can be imitated by this process, I need only mention
oneinstance, Upon one occasion, having made an image of a
piece of lace of an elaborate pattern, I showed it to some per-
sons at the distance ofa few feet, with the inquiry, whether it

200 Mr. Talbot’s Account of the

was a good representation ? when the reply was, ‘ That they
were not to be so easily deceived, for that it was evidently no
picture, but the piece of lace itself?”

At the very commencement of my experiments upon this
subject, when I saw how beautiful were the images which
were thus produced by the action of light, I regretted the
more that they were destined to have such a brief existence,
and I resolved to attempt to find out, if possible, some me-
thod of preventing this, or retarding it as much as possible.
The following considerations led me to conceive the possi-
bility of discovering a preservative process.

The nitrate of silver, which has become black by the action
of light, is no longer the same chemical substance that it was
before. Consequently, if a picture produced by solar light is
subjected afterwards to any chemical process, the white and
dark parts of it will be differently acted upon; and there is
no evidence that after this action has taken place, these white
and dark parts will any longer be subject to a spontaneous
change; or, if they are so, still it does not follow that that
change will now tend to assimilate them to each other. In
case of their remaining dissimilar, the picture will remain vi-
sible, and therefore our object will be accomplished.

If it should be asserted that exposure to sunshine would
necessarily reduce the whole to one uniform tint, and destroy
the picture, the onus probandi evidently lies on those who
make the assertion. If we designate by the letter A the ex-
posure to the solar light, and by B some indeterminate che-
mical process, my argument was this: Since it cannot be
shown, @ prior, that the final result of the series of processes
ABA will be the same with that denoted by BA, it will
therefore be worth while to put the matter to the test of ex-
periment, viz. by varying the process B until the right one be
discovered, or until so many trials have been made as to pre-
clude all reasonable hope of its existence.

My first trials were unsuccessful, as indeed I expected ;
but after some time I discovered a method which answers
perfectly, and shortly afterwards another. On one of these
more especially I have made numerous experiments; the
other I have comparatively little used, because it appears to
require more nicety in the management. It is, however,
equal, if not superior, to the first in brilliancy of effect.

This chemical change, which I call the preserving process,
is far more effectual than could have been anticipated. ‘The
paper, which had previously been so sensitive to light, becomes
completely insensible to it, insomuch that I am able to show
the Society specimens which have been exposed for an hour

Art of Photogenic Drawing. 201

to the full summer sun, and from which exposure the image
has suffered nothing, but retains its perfect whiteness.

§ 4. On the Art of fixing a Shadow.

The phenomenon which I have now briefly mentioned ap-
pears to me to partake of the character of the marvellous,
almost as much as any fact which physical investigation has
yet brought to our knowledge. The most transitory of things,
a shadow, the proverbial emblem of all that is fleeting and
momentary, may be fettered by the spells of our “ natural
magic,” and may be fixed for ever in the position which it
seemed only destined for a single instant to occupy.

This remarkable phzenomenon, of whatever value it may
turn out in its application to the arts, will at least be accepted
as a new proof of the value of the inductive methods of modern
science, which by noticing the occurrence of unusual circum-
stances (which accident perhaps first manifests in some small
degree), and by following them up with experiments, and
varying the conditions of these until the true law of nature
which they express is apprehended, conducts us at length to
consequences altogether unexpected, remote from usual ex-
perience, and contrary to almost universal belief. Such is the
fact, that we may receive on paper the fleeting shadow, arrest
it there, and in the space of a single minute fix it there so
firmly as to be no more capable of change, even if thrown
back into the sunbeam from which it derived its origin.

§ 5.

Before going further, I may however add, that it is not
always necessary to use a preserving process. This I did not
discover until after I had acquired considerable practice in
this art, having supposed at first that all these pictures would
ultimately become indistinct if not preserved in some way
from the change. But experience has shown to me that there
are at least two or three different ways in which the process
may be conducted, so that the images shall possess a charac-
ter of durability, provided they are kept from the action of di-
rect sunshine. ‘These ways have presented themselves to no-
tice rather accidentally than otherwise; in some instances
without any particular memoranda having been made at the
time, so that I am not yet prepared to state accurately on what
particular thing this sort of semi-durability depends, or what
course is best to be followed in order to obtain it. But asI have
found that certain of the images which have been subjected to
no preserving process remain quite white and perfect after the
lapse of a year or two, and indeed show no symptom whatever

202 Mr. Talbot’s Account of the

of changing, while others differently prepared (and left unpre-
served) have grown quite dark in one tenth of that time, I
think this singularity requires to be pointed out. Whether
it will be of much value I do not know; perhaps it will be
thought better to incur at first the small additional trouble of
employing the preserving process, especially as the drawings
thus prepared will stand the sunshine; while the unpreserved
ones, however well they last in a portfolio or in common day-
light, should not be risked in a very strong light, as they would
be liable to change thereby, even years after their original for-
mation. This very quality, however, admits of useful appli-
cation. For this semi-durable paper, which retains its white-
ness for years in the shade, and yet suffers a change whenever
exposed to the solar light, is evidently well suited to the use of
a naturalist travelling in a distant country, who may wish to
keep some memorial of the plants he finds, without having the
trouble of drying them and carrying them about with him. He
would only have to take a sheet of this paper, throw the image
upon it, and replace it in his portfolio. The defect of this
particular paper is, that in general the ground is not even;
but this is of no consequence where utility alone, and not
beauty of effect is consulted.

§ 6. Portraits.

Another purpose for which I think my method will be
found very convenient, is the making of outline portraits, or
silhouettes. These are now often traced by the hand from
shadows projected by a candle. But the hand is liable to err
from the true outline, and a very small deviation causes a no-
table diminution in the resemblance. I believe this manual
process cannot be compared with the truth and fidelity with
which the portrait is given by means of solar light.

§ 7. Paintings on Glass.

The shadow-pictures which are formed by exposing paint-
ings on glass to solar light are very pleasing. ‘The glass itself,
around the painting, should be blackened; such, for instance,
as are often employed for the magic lantern. The paintings
on the glass should have no bright yellows or reds, for these
stop the violet rays of light, which are the only effective ones,
The pictures thus formed resemble the productions of the art-
ist’s pencil more, perhaps, than any of the others. Persons
to whom I have shown them have generally mistaken them for
such, at the same time observing, that the style was new tothem,
and must be one rather difficult to acquire. It is in these pic-

Art of Photogenic Drawing. 203

tures only that, as yet, I have observed indications of colour. I
have not had time to pursue this branch of the inquiry further.
It would be a great thing if by any means we could accomplish
the delineation of objects in their natural colours. I am not
very sanguine respecting the possibility of this; yet, as I have
just now remarked, it appears possible to obtain at least some
indication of variety of tint.

§ 8. Application to the Microscope.

I now come to a branch of the subject which appears to me
very important and likely to prove extensively useful, the ap-
plication of my method of delineating objects to the solar mi-
croscope.

The objects which the microscope unfolds to our view, cu-
rious and wonderful as they are, are often singularly compli-
cated. ‘The eye, indeed, may comprehend the whole which
is presented to it in the field of view; but the powers of the
pencil fail to express these minutiee of nature in their innume-
rable details. What artist could have skill or patience enough
to copy them? or granting that he could do so, must it not
be at the expense of much most valuable time, which might be
more usefully employed ?

Contemplating the beautiful picture which the solar micro-
scope produces, the thought struck me, whether it might not
be possible to cause that image to impress itself upon the
paper, and thus to let Nature substitute her own inimitable
pencil, for the imperfect, tedious, and almost hopeless attempt
of copying a subject so intricate.

My first attempt had no success. Although I chose a
bright day, and formed a good image of my object upon pre-
pared paper, on returning at the expiration of an hour I found
that no effect had taken place. I was therefore half inclined
to abandon this experiment, when it occurred to me, that there
was no reason to suppose that either the nitrate or muriate of
silver, as commonly obtained, was the most sensitive substance
that exists to the action of the chemical rays*; and though
such should eventually prove to be the fact, at any rate it was
not to be assumed without proof. I therefore began a course
of experiments in order to ascertain the influence of various
modes of preparation, and I found these to be signally differ-
ent in their results. I considered this matter chiefly in a prac-
tical point of view; for as to the theory, I confess that I can-
not as yet understand the reason why the paper prepared in
one way should be so much more sensitive than in another,

* Sir H. Davy somewhere says that the iodide is more sensitive, which I
have hardly found to be the case in my experiments.

204 Mr. Talbot’s Account of the

The result of these experiments was the discovery of a mode
of preparation greatly superior in sensibility to what I had
originally employed : and by means of this, all those effects
which I had before only anticipated as theoretically possible
were found to be capable of realization.

When a sheet of this, which I shall call ‘* Sensitive Paper,”
is placed in a dark chamber, and the magnified image of some
object thrown on it by the solar microscope, after the lapse of
perhaps a quarter of an hour, the picture is found to be com-
pleted. I have not as yet used high magnifying powers, on
account of the consequent enfeeblement of the light. Of course,
with a more sensitive paper, greater magnifying power will
become desirable.

On examining one of these pictures, which I made about
three years and a half ago, I find, by actual measurement of
the picture and the object, that the latter is magnified seven-
teen times in linear diameter, and in surface consequently 289
times. I have others which I believe are considerably more
magnified; but I have lost the corresponding objects, so that
I cannot here state the exact numbers.

Not only does this process save our time and trouble, but
there are many objects, especially microscopic crystallizations,
which alter so greatly in the course of three or four days (and
it could hardly take any artist less to delineate them in all
their details), that they could never be drawn in the usual way.

I will now describe the degree of sensitiveness which this
paper possesses, premising that I am far from supposing that
I have reached the limit of which this quality is capable. On
the contrary, considering the few experiments which I have
made, (few, that is, in comparison with the number which it
would be easy to imagine and propose) I think it most likely,
that other methods may be found, by which substances may
be prepared, perhaps as much transcending in sensitiveness
the one which I have employed, as that does the nitrate of
silver which I used in my first experiments.

But to confine myself to what I have actually accomplished,
in the preparation of a very sensitive paper. When a sheet
of this paper is brought towards a window, not one through
which the sun shines, but looking in the opposite direction, it
immediately begins to discolour. For this reason, if the paper
is prepared by daylight, it must by no means be left uncovered,
but as soon as finished be shut up in a drawer or cupboard
and there left to dry, or else dried at night by the warmth of
a fire. Before using this paper for the delineation of any ob-
ject, I generally approach it for a little time towards the light,
thus intentionally giving it a slight shade of colour, for the

Art of Photogenic Drawing. 205

purpose of seeing that the ground is even. If it appears so
when thus tried toa small extent, it will generally be found to
prove so in the final result. But if there are some places or
spots in it which do not acquire the same tint as the rest, such
a sheet of paper should be rejected: for there is a risk that,
when employed, instead of presenting a ground uniformly
dark, which is essential to the beauty of the drawing, it will
have large white spots, places altogether insensible to the
effect of light. This singular circumstance I shall revert to
elsewhere: it is sufficient to mention it here.

The paper then, which is thus readily sensitive to the light
of a common window, is of course much more so to the direct
sunshine. Indeed, such is the velocity of the effect then pro-
duced, that the picture may be said to be ended almost as
soon as it is-begun.

To give some more definite idea of the rapidity of the pro-
cess, I will state, that after various trials the nearest evaluation
which I could make of the time necessary for obtaining the
picture of an object, so as to have pretty distinct outlines,
when I employed the full sunshine, was half a second.

§ 9. Architecture, Landscape, and external Nature.

But perhaps the most curious application of this art is the
one I am now about to relate. At least it is that which has
appeared the most surprising to those who have examined my
collection of pictures formed by solar light.

Every one is acquainted with the beautiful effects which are
produced by a camera obscura and has admired the vivid pic-
ture of external nature which it displays. It had often oc-
curred to me, that if it were possible to retain upon the paper
the lovely scene which thus illuminates it for a moment, or if
we could but fix the outline of it, the lights and shadows, di-
vested of all colour, such a result could not fail to be most in-
teresting. And however much I might be disposed at first to
treat this notion as a scientific dream, yet when I had suc-
ceeded in fixing the images of the solar microscope by means
of a peculiarly sensitive paper, there appeared no longer any
doubt that an analogous process would succeed in copying the
objects of external nature, although indeed they are much less
illuminated.

Not having with me in the country a camera obscura of any
considerable size, I constructed one out of a large box, the
image being thrown upon one end of it by a good object glass
fixed in the opposite end. This apparatus being armed with
a sensitive paper, was taken out in a summer afternoon and
placed about one hundred yards from a building favourably

206 Mr. Talbot’s Account of the

illuminated by the sun. An hour or two afterwards I opened
the box, and I found depicted upon the paper a very distinct
representation of the building, with the exception of those
parts of it which lay in the shade. A little experience in this
branch of the art showed me that with smaller camere obscura
the effect would be produced in a smaller time. Accordingly
I had several small boxes made, in which I fixed lenses of
shorter focus, and with these I obtained very perfect but ex-
tremely small pictures: such as without great stretch of ima-
gination might be supposed to be the work of some Lilliputian
artist. They require indeed examination with a lens to dis-
cover all their minutia.

In the summer of 1835 I made in this way a great number
of representations of my house in the country, which is well
suited to the purpose, from its ancient and remarkable archi-
tecture. And this building I believe to be the first that was
ever yet known #o have drawn its own picture.

The method of proceeding was this: having first adjusted
the paper to the proper focus in each of these little camera, 1
then took a number of them with me out of doors and placed
them in different situations around the building. After the
lapse of half an hour I gathered them all up, and brought
them within doors to open them. When opened, there was
found in each a miniature picture of the objects before which
it had been placed.

To the traveller in distant lands, who is ignorant, as too
many unfortunately are, of the art of drawing, this little inven-
tion may prove of real service; and even to the artist himself,
however skilful he may be. For although this natural process
does not produce an effect much resembling the productions
of his pencil, and therefore cannot be considered as capable
of replacing them, yet it is to be recollected that he may often
be so situated as to be able to devote only a single hour to the
delineation of some very interesting locality. Now, since
nothing prevents him from simultaneously disposing, in dif-
ferent positions, any number of these little camera, it is evident
that their collective results, when examined afterwards, may
furnish him with a large body of interesting memorials, and
with numerous details which he had not had himself time either
to note down or to delineate.

§ 10. Delineations of Sculpture.

Another use which I propose to make of my invention is
for the copying of statues and bas-reliefs. I place these in
strong sunshine, and put before them at a proper distance,
and in the requisite position, a small camera obscura contain-

Art of Photogenic Drawing. 207

ing the prepared paper. In this way I have obtained images
of various statues, &c. I have not pursued this branch of the
subject to any extent; but I expect interesting results from it,
and that it may be usefully employed under many circum-
stances.

§ 11. Copying of Engravings.

The invention may be employed with great facility for ob-
taining copies of drawings or engravings, or facsimiles of
MSS. For this purpose the engraving is pressed upon the
prepared paper, with its engraved side in contact with the
latter. The pressure must be as uniform as possible, that
the contact may be perfect ; for the least interval sensibly in-
jures the result, by producing a kind of cloudiness in lieu of
the sharp strokes of the original.

When placed in the sun, the solar light gradually traverses
the paper, except in those places where it is prevented from
doing so by the opake lines of the engraving. It therefore of
course makes an exact image or print of the design. This is
one of the experiments which Davy and Wedgwood state that
they tried, but failed, from want of sufficient sensibility in
their paper.

The length of time requisite for effecting the copy depends
on the thickness of the paper on which the engraving has
been printed. At first I thought that it would not be possi-
ble to succeed with thick papers; but I found on trial that
the success of the method was by no means so limited. It is
enough for the purpose, if the paper allows any of the solar
light to pass. When the paper is thick, I allow half an hour
for the formation of a good copy. In this way I have copied
very minute, complicated, and delicate engravings, crowded
with figures of small size, which were rendered with great di-
stinctness.

The effect of the copy, though of course unlike the original,
(substituting as it does lights for shadows, and vice versd,) yet
is often very pleasing, and would, I think, suggest to artists
useful ideas respecting light and shade.

It may be supposed that the engraving would be soiled or
injured by being thus pressed against the prepared paper.
There is not much danger of this, provided both are perfectly
dry. It may be well to mention, however, that in case any
stain should be perceived on the engraving, it may be readily
removed by a chemical application which does no injury
whatever to the paper.

In copying engravings, &c. by this method, the lights and
shadows are reversed, consequently the effect is wholly al-
tered. Butif the picture so obtained is first preserved so as

208 Mr. Talbot's Account of the

to bear sunshine, it may be afterwards itself employed as an
object to be copied; and by means of this second process
the lights and shadows are brought back to their original
disposition. In this way we have indeed to contend with the
imperfections arising from two processes instead of one; but I
believe this will be found merely a difficulty of manipulation.
I propose to employ this for the purpose more particularly of
multiplying at small expense copies of such rare or unique en-
gravings as it would not be worth while to re-engrave, from
the limited demand for them.

I will now add a few remarks concerning the very singular
circumstance, which I have before briefly mentioned, viz. that
the paper sometimes, although intended to be prepared of the
most sensitive quality, turns out on trial to be wholly insensible
to light, and incapable of change. The most singular part of
this is the very small difference in the mode of preparation
which causes so wide a discrepancy in the result. For instance,
a sheet of paper is all prepared at the same time, and with the
intention of giving it as much uniformity as possible: and yet,
when exposed to sunshine, this paper will exhibit large white
spots of very definite outline, where the preparing process
has failed; the rest of the paper, where it has succeeded, turn-
ing black as rapidly as possible. Sometimes the spots are of
a pale tint of ccerulean blue, and are surrounded by exceed-
ingly definite outlines of perfect whiteness, contrasting very
much with the blackness of the part immediately succeeding.
With regard to the theory of this, I am only prepared to state
as my opinion at present, that it is a case of what is called
** unstable equilibrium.” ‘The process followed is such as to
produce one of two definite chemical compounds; and when
we happen to come near the limit which separates the two
cases, it depends upon exceedingly small and often impercep-
tible circumstances, which of the two compounds shall be
formed. That they are both definite compounds, is of course
at present merely my conjecture ; that they are signally differ-
ent, is evident from their dissimilar properties.

I have thus endeavoured to give a brief outline of some of
the peculiarities attending this new process, which I offer to
the lovers of science and nature. ‘That it is susceptible of
great improvements, I have no manner of doubt; but even in
its present state I believe it will be found capable of many use-
ful and important applications besides those of which I have
given a short account in the preceding pages.

, 24 5<_

I SEO NY,

Processes employed in Photogenic Drawing. 209

An Account of the Processes employed in Photogenic Drawing,
in a Letter to Samuel H. Christie, Esq., Sec. R.S.,
Jrom H. Talbot, Esq., F.R.S.*

Dear Sir,—In compliance with the request of several scien-
tific friends, who have been much interested with the account
of the art of Photogenic Drawing, which I had the honour of
presenting to the Royal Society on the 31st of last month, I
will endeavour to explain, as briefly as I can, but at the same
time without omitting any thing essential, the methods which
I have hitherto employed for the production of these pictures.

If this explanation, on my part, should have the effect of
drawing new inquirers into the field, and if any new discove-
ries of importance should be the result, as I anticipate, and
especially if any means should: be discovered by which the
sensitiveness of the paper can be materially increased, I shall
be the first to rejoice at the success; and in the meanwhile, I
shall endeavour, as far as I may be able, to prosecute the in-
quiry myself.

The subject naturally divides itself into two heads; viz. the
preparation of the paper, and the means of fixing the design.

(2.) Preparation of the paper.—In order to make what may
be called ordinary photogenic paper, I select, in the first place,
paper of a good firm quality and smooth surface. I do not
know that any answers better than superfine writing paper.
I dip it into a weak solution of common salt, and wipe it dry,
by which the salt is uniformly distributed throughout its sub-
stance. I then spread a solution of nitrate of silver on one
surface only, and dry it at the fire. The solution should not
be saturated, but six or eight times diluted with water. When
dry, the paper is fit for use.

I have found by experiment, that there is a certain propor-
tion between the quantity of salt and that of the solution of
silver, which answers best and gives the maximum effect. If
the strength of the salt is augmented beyond this point, the
effect diminishes, and, in certain cases, becomes exceedingly
small.

This paper, if properly made, is very useful for all ordinary
photogenic purposes. For example, nothing can be more
perfect than the images it gives of leaves and flowers, especi-
ally with a summer sun: the light passing through the leaves
delineates every ramification of their nerves.

Now, suppose we take a sheet of paper thus prepared, and
wash it with a saturated solution of salt, and then dry it. We
shall find (especially if the paper has been kept some weeks

* Read before the Royal Society, Feb. 21, 1839,
Phil. Mag. S. 3. Vol. 14. No.88. Mar.1839. P

210 Mr. Talbot on Photogenic Drawing.

before the trial is made) that its sensibility is greatly diminish-
ed, and, in some cases, seems quite extinct. But if it is again
washed with a liberal quantity of the solution of silver, it be-
comes again sensible to light, and even more so than it was at
first. In this way, by alternately washing the paper with salt
and silver, and drying it between times, I have succeeded in
increasing its sensibility to the degree that is requisite for re-
ceiving the images of the camera obscura.

In conducting this operation it will be found that the results
are sometimes more and sometimes less satisfactory in conse-
quence of small and accidental variations in the proportions
employed. It happens sometimes that the chloride of silver
is disposed to darken of itself, without any exposure to light:
this shows that the attempt to give it sensibility has been car-
ried too far. The object is, to approach to this condition as
near as possible without reaching it; so that the substance
may be in a state ready to yield to the slightest extraneous
force, such as the feeble impact of the violet rays when much
attenuated. Having therefore prepared a number of sheets
of paper with chemical proportions slightly different from one
another, let a piece be cut from each, and, having been duly
marked or numbered, let them be placed side by side in a very
weak diffused light for about a quarter of an hour. Then, if
any one of them, as frequently happens, exhibits a marked
advantage over its competitors, I select the paper which bears
the corresponding number to be placed in the camera obscura.

(2.) Method of fixing the images.—After having tried am-
monia, and several other reagents, with very imperfect success,
the first thing which gave me a successful result was the zodide
of potassium, much diluted with water. If a photogenic picture
is washed over with this liquid, an zodide of silver is formed
which is absolutely unalterable by sunshines. This process re-
quires precaution ; for if the solution is too strong, it attacks
the dark parts of the picture. It is requisite, therefore, to find
by trial the proper proportions. ‘The fixation of the pictures
in this way, with proper management, is very beautiful and
lasting. ‘The specimen of Jace which I exhibited to the So-
ciety, and which was made five years ago, was preserved in
this manner.

But my usual method of fixing is different from this, and
somewhat simpler, or at least requiring less nicety. It con-
sists in immersing the picture in a strong solution of common
salt, and then wiping off the superfluous moisture, and drying
it. It is sufficiently singular that the same substance which
is so useful in gzving sensibility to the paper, should also be
capable, under other circumstances, of destroying it; but such
is, nevertheless, the fact.

Royal Society. 211

Now, if the picture which has been thus washed and dried
is placed in the sun, the white parts colour themselves of a
pale lilac tint, after which they become insensible. Numerous
experiments have shown to me that the depth of this lilac tint
varies according to the quantity of salt used, relatively to the
quantity of silver. But, by properly adjusting these, the
images may, if desired, be retained of an absolute whiteness,
I find I have omitted to mention that those preserved by zodine
are always of a very pale primrose yellow; which has the ex-
traordinary and very remarkable property of furning to a full
gaudy yellow whenever it is exposed to the heat of a fire, and
recovering its former colour again when it is cold.

lam, &c.
H. Fox Taxzor.

XXXVIII. Proceedings of Learned Societies.
ROYAL SOCIETY.
[Continued from p. 141.]

Dec. 6, 1838.—A paper was in part read, entitled, ‘‘ Experi-
mental Researches in Electricity.” Fifteenth Series.—‘‘ Note of the
Character and Direction of the Electric Force of the Gymnotus.”
By Michael Faraday, Esq., D.C.L., F.R.S., &e.

Dec. 13, 1838.—The reading of a paper, entitled, ‘‘ Experimental
Researches in Electricity.” Fifteenth Series.-—‘‘Note of the Cha-
racter and Direction of the Electric Force of the Gymnotus.’’ By
Michael Faraday, Esq., D.C.L., F.R.S., &c., was resumed and con-
cluded.

The author first briefly refers to what has been done by others in
establishing the identity of the peculiar power in the Gymnotus and
Torpedo with ordinary electricity, and then in reference to the in-
tended conveyance to this country of Gymnoti from abroad, gives
the instructions which he himself had received from Baron Humboldt
for that purpose. A living Gymnotus, now in the possession of the
Proprietors of the Gallery of Science in Adelaide Street, was placed
for a time at the disposal of the author for the purpose of research,
upon which he proceeded, with suitable apparatus, to compare its
power with ordinary and voltaic electricity, and to obtain the direction
of the force. Without removing it from the water he was able to ob-
‘tain not only the results procured by others, but the other electrical
phenomena required so as to leave no gap or deficiency in the evi-
dence of identity. The shock, in very varied circumstances of posi-
‘tion, was procured: the galvanometer affected; magnets were made ;
a wire was heated; polar chemical decomposition was effected, and
the spark obtained. By comparative experiments made with the

* Prof. Faraday’s preceding series of Exp. Res. in Electricity have been

iven, either entire or in abstract, in various volumes of Lond. and Edinb.
hil, Mag,—Ebir.
|

212 Royal Society.

animal and a powerful Leyden battery, it was concluded that the
quantity of force in each shock of the former was very great. It was
also ascertained by all the tests capable of bearing on the point, that
the current of electricity was, in every case, from the anterior parts
of the animal through the water or surrounding conductors to the
posterior parts. The author then proceeds to express his hope that
by means of these organs and the similar parts of the Torpedo, a
relation as to action and re-action of the electric and nervous powers
may be established experimentally ; and he briefly describes the form
of experiment which seems likely to yield positive results of this
kind*.

Dec. 20, 1838.—A paper was read, entitled, ‘‘On the Curvature
of Surfaces.” By John R. Young, Esq. Communicated by John
W. Lubbock, Esq., M.A., V.P. and Treas. R.S.

The principal object of this paper is, to remove the obscurity in
which that part of the theory of the curvature of surfaces which re-
lates to umbilical points has been left by Monge and Dupim, to
whom, however, subsequently to the labours of Euler, we are
chiefly indebted for a comprehensive and systematic theory of the
curvature of surfaces. In it the author shows, that the lines of cur-
vature at an umbilic are not, as at other points on a surface, two in
number, or, as had been stated by Dupin, limited; but that they pro-
ceed in every possible direction from the umbilic.

The obscurity complained of is attributed to the inaccurate con-
ceptions entertained by Monge and Dupin, of the import of the sym-

bol in the analytical discussion of this question, the equation which

determines the directions of the lines of curvature taking the form
dyy\2 dy as
0(82)'+ 0 (44) + 0=0
at an umbilic. After stating that Dupin has been guided by the de-
termination of the differential calculus, the author remarks, that in

no case is the differential calculus competent to decide whether the

form which a general analytical result takes in certain particular hy-
potheses, as to the arbitrary quantities entering that result, has or
has not innumerable values. He then states the principle, that those
values of the arbitrary quantities (and none else) which render the
equations of condition indeterminate must also render the final re-
sult, to which they lead, equally indeterminate ; and that, therefore,

when such result assumes the form its true character is to be

tested by the equations that have led to it, after these have been
modified by the hypothesis from which that form has arisen.
In a “‘ Mémoire sur la Courbure des Surfaces,” (Journal de l’Ecole

* In the First Series of the Philosophical Magazine, vol. xv. p. 126,
will be found a translation of E. Geoffroy’s Memoir on the Anatomy of
the Electrical Fishes, including that of the Gymnotus.—Eprr.

Royal Society. 213

Polytechnique, Tom. XIII.), Poisson has arrived at the conclusion,
that the number of lines of curvature passing through an umbilical
point is infinite, and that those selected by Dupin differ from the
others only by satisfying an additional differential equation; those
others equally satisfying the conditions of a line of curvature.
These are precisely the conclusions arrived at by the author. As,
however, he considers that the mode of investigation pursued by
Poisson is peculiar and ill adapted to the objects apparently in view,
namely, to reconcile the results of Monge and Dupin and to remove
their obscurities, he was induced to investigate some of the more
important properties of curve surfaces, by a method somewhat dif-
ferent from that usually employed.

Adopting LE CX ¥)
as the general equation of any surface; by attributing to X, Y, Z,
increments 2, y, z, and assuming that the axis Z coincides with the
normal to the surface, or that the plane @ y is parallel to the tangent
plane, an equation equivalent to, and nearly identical with, Dupin’s
equation of his indicatrix, is readily deduced. From this are imme-
diately derived some properties of the radii of curvature, first shown
by Dupin ; and likewise the theorem of Meusnier. The author then
enters upon the subject of the lines of curvature.

From the equations

A= 0, B= 0,

of the normal to the surface at a point on it, the equations of
normal at a point near to the former are determined. That these
normals may intersect, which is the condition giving the directions
of the lines of curvature, the two sets of equations must simulta-
neously exist ; and hence are deduced the differential equations of
condition for the lines of curvature,

dA dA dy a@B dB dy _
de tdy dx det dy’ da
By this method, which fundamentally is not very different from that
of Monge, substituting the usual expressions for A and B, the equa-
tion that determines the directions of the lines of curvature is de-
duced, in the form in which it had been previously given by Monge
and Dupin.
This final equation becoming at an umbilic of the form,

0 (28)'+0 (82) 40-0,

in which oy may be indeterminate, the author inquires how this in-
2

= 0.

determinate form will affect the equations of condition. As by this

supposition, these are reduced to equations from which would result

the conditions that would render all the coefficients of the determi-

ning equation 0, it is inferred that ag must be indeterminate, and
da

that therefore, at an umbilic there issue lines of curvature in all di-
rections.

214 Royal Society :—Mr. Hopkins on the

Of these lines of curvature, it is possible that some may be di-
stinguished from others, by proceeding from the point in more inti-
mate contact with the osculating sphere, and it is therefore necessary
to determine the analytical character of such particular lines of cur-
vature. With this view, the author resumes the equation of the
normal in the immediate vicinity of the umbilic. He then points out,
that a straight line, whose equations contain the second differential
coefficients, thus involving a new condition, will coincide more
nearly with this normal, than can any straight line not having that
condition. That the lines may intersect in the centre of the oscu-
lating sphere, their equations must simultaneously exist; and thus,
that which most nearly coincides with the normal in the immediate
vicinity of the umbilic has the new conditions,

d? A aA dy dA dy

dae t “dedy dx t dy “dx

d?B d*B dy @7B dy

da t*dedy datdyp ‘dx
in addition to the former ones.

From this it appears, that when the direction of a line of curvature
issuing from an umbilic is such as to fulfil, besides the ordinary con-
ditions, the foregoing new conditions, that line of curvature will lie
more closely to the osculating sphere than any other not satisfying
these additional equations. These new conditions arise from differ-
entiating the preceding ones with respect to # and y, considered as

dependent, regarding =, as constant; and as these are equivalent

to a single condition (Monge’s and Dupin’s equation) it will be suf-
ficient to differentiate this, under the above restrictions, in order to
obtain a single condition equivalent to the new ones. As this single
condition will appear under the form of an equation of the third

degree in Be there will, in general, be at least one line of curvature,
a

proceeding from the umbilic, of more than ordinary closeness to the
osculating sphere ; and there may be three. If, indeed, this equa-
tion of the third degree should, like that of the second from which
it is deduced, be identical for the coordinates of the umbilic, it is
obvious from the investigation, that we must then proceed to an-
other differentiation; and so on, till we arrive at a determinate
equation, the real roots of which will make known the number and
directions of the lines of closest contact.

When, however, the author remarks in conclusion, all the lines of
curvature issuing from the umbilic are equally close to the oscu-
lating sphere, then these successive differentiations will either at
length exhaust the coefficients, and thus no determinate equation

will arise ; or else they will conduct to an equation whose roots are
all imaginary: and one or other of these circumstances must always
take place at the vertex of a surface of revolution.

The Society adjourned over the Christmas Recess to meet again
on the 10th of January. ;

State of the Interior of the Earth. 215

January 10, 1839.—A paper was read, entitled, ‘On the Laws
of Mortality.” By Charles Jellicoe, Esq. Communicated by P.
M. Roget, M.D., Sec. R.S.

The author, considering that the variations and discrepancies in
the annual decrements of life which are exhibited in the tables of
mortality hitherto published would probably disappear, and that
these decrements would follow a perfectly regular and uniform law,
if the observations on which they are founded were sufficiently nu-
merous, endeavours to arrive at an approximation to such a law, by
proper interpolations in the series of the numbers of persons living
at every tenth year of human life. The method he proposes, for
the attainment of this object, is that of taking, by proper formule,
the successive orders of differences, until the last order either disap-
pears, or may be assumed equal to zero. With the aid of such dif-
ferences, of which, by applying these formule, he gives the calcula-
tion, he constructs tables of the annual decrements founded princi-
pally on the results of the experience of the Equitable Assurance
Society.

January 17.—A paper was read, entitled, ‘‘ On the state of the
Interior of the Earth.”” By W. Hopkins, Esq. A.M., F.R.S., Second
Memoir. ‘‘ On the Phenomena of Precession and Nutation, assuming
the Fluidity of the Interior of the Earth*.”

In this memoir the author investigates the amount of the luni-
solar precession and nutation, assuming the earth to consist of a
solid spheroidal shell filled with fluid. For the purpose of present-
ing the problem under its most simple form, he first supposes the
solid shell to be bounded by a determinate inner spheroidal surface,
of which the ellipticity is equal to that of the outer surface; the
change from the solidity of the shell to the fluidity of the included
mass being, not gradual, but abrupt. He also here supposes both
the shell and the fluid to be homogeneous, and of equal density.
The author then gives the statement of the problem which he pro-
poses to investigate ; the investigation itself, which occupies the re-
mainder of the paper, being wholly analytical, and insusceptible of
abridgement. The following, however, are the results to which he-
is conducted by this laborious process: namely, that, on the hypo-
thesis above stated, 1. The Precession will be the same, whatever be
the thickness of the shell, as if the whole earth were homogeneous
and solid. 2. The Lunar Nutation will be the same as for the homo-
geneous spheroid to such a degree of approximation that the differ-
ence would be inappreciable to observation. 3. The Solar Nutation.
will be sensibly the same as for the homogeneous spheroid, unless
the thickness of the shell be very nearly of a certain value, namely,
something less than one quarter of the earth’s radius; in which case
this nutation might become much greater than for the solid spheroid. °
4, In addition to the above motions of precession and nutation, the
pole of the earth’ would have a small circular motion, depending en-
tirely on the internal fluidity. The radius of the circle thus de-

* An abstract of Mr. Hopkins’s First Memoir will be found in our
Number for January, pres. vol. p. 52.—Eprr.

216 Royal Society :—Prof Necker’s

scribed would be greatest when the thickness of the shell was the
least: but the inequality thus produced would not, for the smallest
thickness of the shell, exceed a quantity of the same order as the
polar nutation, and for any but the most inconsiderable thickness of
the shell would be entirely inappreciable to observation.

In his next communication, the author purposes considering the
case in which both the solid shell and the inclosed fluid mass are of
variable density.

«« Appercu sur une maniére nouvelle d’envisager la théorie cristal-
lographique dans le but d’établir les rapports de celle-ci avec la forme
sphérique, ou elliptique, des molécules, ainsi qu’avec l’effet des mi-
lieux sur la forme cristalline.” Par M. L. A. Necker. Communicated
by P. M. Roget, M.D., Sec. R.S.

In this communication, after adverting to Haiiy’s theory of cry-
stallization, in which the molecules are considered to be polyhedrons,
to the views subsequently taken by Wollaston and Davy, and par-
ticularly to Brewster’s conclusions, that there ought to be different
forms of molecules, some spherical, some elliptical with two
equal axes, and a third unequal to these, and others elliptical with
three unequal axes; M. Necker states, that Mr. Dana is the only
mineralogist who has attempted to introduce into crystallography
the consideration of molecules with curved surfaces. Although,
adopting the forms proposed by Brewster, and adding to them those
of oblique solids, by introducing the idea of polarity in the axes of
crystallization, Mr. Dana has successfully applied this molecular
theory to crystallography, yet he goes no farther; and the most im-
portant and difficult steps in this branch of physical science still re-
main to be made, and many phenomena in crystallization, with the
cause of which we are at present wholly unacquainted, still require
to be explained by the theory.’ ‘The author particularly refers to
the important facts discovered by MM. Leblanc and Beudant, of
the influence that solutions or mediums in which bodies crystallize
have on the secondary forms which these bodies take; and states,
that the present views of crystallography afford not even a glimpse
of the least relation between such forms and the properties of the
mediums. Why, he asks, does pure water appear, in general, to
tend to simplify the forms, precisely as do certain mixtures, those of
chlorite in axinite, quartz, felspar, &c., and why, on the contrary,
do other mediums, acid or earthy, complicate them?

Impressed with the importance which must attach to the solution
of such questions, M. Necker offers some ideas which long medita-
tion on this important Subject has suggested to him.

Adopting the ellipsoid as the form of the molecule, he remarks,
that the more complicated the form of the crystal, the more the
number of its faces increases, and the more, at the same time, does
it approach to the ellipsoidal form of the molecule ; and, on the con-
trary, the simpler the form becomes, the more does it recede from
that with a curved surface. All crystalline forms may be considered
as making a part of one or more series, which, in each system of
crystallization, have for extreme terms, on the one side, the most sim-

Views of the theory of Crystallography. 217

ple solid of the system, or that which has the least number possible
of faces, and on the other, the solid having the greatest number,
namely a sphere or an ellipsoid. Although it is more convenient in
the calculation of forms to start from the most simple polyhedral
forms in order to arrive at the more complex, nothing proves that
such has been the route which nature has followed. As long as we
considered the integral molecules as polyhedral, it appeared natural
to view them as grouping in polyhedrons ; but when once we cease

’ to admit polyhedral molecules, it then becomes most natural to sup-

pose, that ellipsoidal molecules should have a tendency, more or less
decided, to group in solids of the same form as themselves, when no
extraneous circumstances interpose an obstacle to this tendency.

In order to give an idea of the kind of effect which would be pro-
duced on the form of the solid by these obstacles, such as the nature
of the medium in which crystallization takes place, a hurried or tu-
multuous crystallization, &c., the author conceives that each mole-
cule, as well as each solid formed by their union, has different axes
of attraction, endued with different degrees of energy, and symme-
trically disposed in groups, the weaker and the most numerous round
the stronger, which are, at the same time, the smallest in number;
all, in short, symmetrically arranged around the principal axes of
crystallization, which are the most energetic of all. Thus we shall
conceive that sort of polarity by which crystallization is distin-
guished from molecular attraction. The effect of obstacles, such
as the attraction exerted by mediums, by interposed bodies, by the
molecular attraction of the molecules themselves, when they arrive
both in too great numbers and too rapidly towards the same point,
will be the annihilation of the weaker axes; whence will follow the
formation of a tangent plane to the spherical or elliptical surface.
If the action of the obstacle goes on increasing, axes of attraction,
which, by their intensity, had resisted the first obstacles, are destroyed
by the new ones; and new tangential planes are produced, in which
those that had been first formed finish by being confounded : thus it
will happen that, by the increase of obstacles, the surface of the solid
from being curved has become polyhedral, and finishes by presenting
only an assemblage of a small number of plane faces, separated by
edges, and placed tangentially at the extremity of the axes whose
forces have longest resisted the action of the obstacles. But since
the most energetic axes are necessarily the least numerous, the greater
the energy they possess, the number of faces which bound the solid
will continually decrease according as the obstacles increase ; until,
at length, the solid, reduced to its most simple form, no longer pre-
sents any but that constituted by the principal axes of crystallization,
terminating at the summits of the solid angles of the simple poly-
hedron, which axes alone have been capable of withstanding the ac-
tion of all the obstacles opposed to the tendency of the molecules to
unite in the form of an ellipsoid.

On this hypothesis, the author explains how common salt, alum,
sulphate of iron, &c., crystallize in pure water in the most simple
forms, the reciprocal attraction of their molecules being controlled

218 Royal Society.

and diminished by the affinity exerted on them by the molecules of
the water; whilst if some of these molecules of water are neutralized
by mixture with another soluble principle, they cease to act as an
obstacle to the crystallization of the body, which then takes forms
more complicated and approaching nearer to that of the normal solid
with a curved surface.

M. Necker considers that the new views he has sketched require,
for their complete developement, many ulterior details, as well as
many new experiments and new facts; but that the tendency which
the crystals of all systems present, to progress towards the curved
surface form appropriate to each system, by the complication of their
forces, is a fundamental fact of the first importance ; and that an ad-
vance has been made by showing the bearing of the important ex-
periments of MM. Leblane and Beudant, and by having brought
the theory of crystallography nearer to those views which the pro-
gress of chemistry and of physics have led us to adopt, relative to
the form of the elementary molecules of bodies.

January 24.—A paper was read, entitled, ‘‘ Experiments made
on a piece of Pejfia silver, saved from the Lady Charlotte, wrecked
on the coast of Ireland in December 1838, as to its capability of
holding water.” By W. D. Haggard, Esq. Communicated by Sir
Henry Ellis, K.H., F.R.S.

Plata Pena, so called, is silver collected by quicksilver after the
ore is pounded; it is then placed in a mould, and by great force the
quicksilver is squeezed out, when it forms a mass, resembling dry
mortar, of great porosity.

Troy Weight. Decrease

ref ; P % Ibs. oz. dwts. in weight.
‘ome weight when taken from the 38 10 0 eek ie

One day placed before the fire ..... ..- BY) OLB Basasedere 1.905

Third day ..s..sescerpoeccseresesgerscecesesoe ADY GOL ION wi scseweaes LRG ent 1}

Fifth day. ¢s,cses-+0-s poeagesseesearweeeare sce SY EN IBY weentsa Ah 011 15

Highth day ..ssee.- ssccseeeeseeeeereeeeeees St TOS Bis eee cnnse 05 3

Weight of water ...sscsccseseverees ges -taacdapass 4.9 3

b Ineree

Vei i ( in weight.
Nene = the piece supposed to th 34 0 2 nas

First day from the fire ..,.....sssseesseeeee AG ONLY dessscexss OR at

Third day DE BOT) setsgares 0 2-2

Fifth day BEA) 1B. ocanpanae 0117

Eighth day ated EN cousare Oras 7)

Gained in water from the air .........seeeeeeee On Ff

Weight after water had been an} 39 119 4 910

Faron Darel aie na Masini a lee Ur os
Total weight of water contained in the piece «..++.+++++ be ae Wi

A paper was also read, entitled, ‘‘ On the Application of the Con-
version of Chlorates and Nitrates into Chlorides, and of Chlorides
into Nitrates, to the determination of several equivalent numbers.”
By Frederick Penny, Esq. Communicated by H. Hennell, Esq.
F.R.S.

Royal Society. 219

The researches which form the subject of this paper were sug-
gested by an inquiry into the most effectual method of ascertaining
the quantity of nitrate of potassa existing in crude saltpetre. ‘The
author found that by the action of hydrochloric acid the nitrate of
potassa was converted into the chloride of potassium; and converse-
ly, that the chloride of potassium might, by the proper regulation of
the temperature, be reconyerted into the nitrate of potassa by the
action of nitric acid. These mutual conversions afforded excellent
means of determining, with great exactness, the relative equivalent
numbers, in the theory of definite proportions, belonging to these
salts, and to their respective constituent elements. The author, ac-
cordingly, pursued the investigation of these numbers by several suc-
cessive steps, of which the details occupy the greater part of the
present paper. He first determines the equivalent of chloride of
potassium by decomposing chlorate of potassa into oxygen and chlo-
ride of potassium; the proportion between which gives the ratio
which the respective equivalent numbers of each bear to one another,
and also to that of chlorate of potassa. The equivalent of nitrate of
potassa is next obtained by converting the chlorate and the chloride
of potassium into that salt; and from these data the equivalents of
chlorine and of nitrogen are deduced. A similar train of inquiry is
next instituted with the corresponding salts having sodium for their
base: chlorate of soda being decomposed into the chloride, and
into the nitrate ; nitrate of soda into chloride; and chloride of so-
dium into nitrate of soda. The results of these different series of
experiments coincide so closely with one another as mutually to con-
firm their general accuracy in the most satisfactory manner. For
the purpose of determining the equivalent numbers of the element-
ary bodies themselves, (namely, chlorine, nitrogen, potassium, and
sodium,) the author employed the intermedium of silver, the several
saline combinations of which with chlorine and with nitric acid were
found to afford peculiar advantages for the accurate determination of
the relative weights of the constituents of these salts, when subjected
to various combinations and decompositions. The conclusions to
which the author arrives with regard to the equivalent numbers for
the six elementary bodies in question, tend to corroborate the views
of the late Dr. Turner, and to overturn the favourite hypothesis that

all equivalent numbers are simple multiples of that for hydrogen.
He finds these numbers to be as follow :

DE oe a wk “cal s

Chlorine ee go es: 2 mad So
CAS i eee 14:02
OLASRITM aa keels 39°08
TER i 4 23°05
Silver...... Aa ee 107°97

The author intends to pursue these inquiries, by applying similar
methods to the investigation of other classes of salts.

January 31.—A paper was read, entitled, ‘‘ Some account of the
Art of Photogenic Drawing, or the Process by which Natural Ob-

220 Geological Society.

jects may be made to delineate themselves without the aid of the
Artist’s Pencil.” By H. F. Talbot, Esq., F.R.S.

This paper is given, entire, in the present Number, p. 196.

February 7.—A paper was read, entitled, “ Notice of a Shock of
an Earthquake felt in the Island of St. Mary’s, one of the Scilly
Islands, on the 21st of January, 1839,’’ in a letter addressed to the
Secretary. By the Rev. George Wordley.

The tremulous motion of the ground is described as being very
slight, and felt chiefly in the south parts of the island. It was ac-
companied by a peculiarly harsh and grating sound, which was only
of momentary duration, and no particular agitation of the sea was
observed.

A paper was in part read, entitled, ‘‘ Observations on the Parallel
Roads of Glen Roy, and of other parts of Lochabar, with an attempt
to prove that they are of Marine Origin.” By Charles Darwin, Esq.,
M.A., F.R.S., Sec. Geol. Soc.

GEOLOGICAL SOCIETY.
[Continued from p. 151.]

Dec. 9, 1838.—A paper on the “‘ Phascolotherium,” being the
second part of the ‘‘ Description of the Remains of Marsupial
Mammalia from the Stonesfield Slate,” by Richard Owen, Esq.,
F.G.S., was read.

Mr. Owen first gave a brief summary of the characters of the
«« Thylacotherium,” described in the first part of the memoir*, and
which he conceives fully prove the mammiferous nature of that
fossil. He stated, that the remains of the split condyles in the spe-
cimen demonstrate their original convex form, which is diametrically
opposite to that which characterizes the same part in all reptiles
and all ovipara ;—that the size, figure and position of the coronoid
process are such as were never yet witnessed in any except a
zoophagous mammal endowed with a temporal muscle sufficiently
developed to demand so extensive an attachment for working
a powerful carnivorous jaw;—that the teeth, composed of dense
ivory with crowns covered witha thick coat of enamel, are every where
distinct from the substance of the jaw, but have two fangs deeply im-
bedded in it ;—that these teeth, which belong to the molar series,
are of two kinds; the hinder being bristled with five cusps, four of
which are placed in pairs transversely across the crown of the teeth,
and the anterior or false molars, having a different form, and only
two or three cusps—characters never yet found united in the teeth
of any other than a zoophagous mammiferous quadruped ;—that the
general form of the jaw corresponds with the preceding more essen-
tial indications of its mammiferous nature. Fully impressed with
the value of these characters, as determining the class to which the
fossils belonged, Mr. Owen stated, that he had sought in the next
place for secondary characters which might reveal the group of

* An abstract of the first part of Prof. Owen’s memoir was given in
our last Number, pres. vol]. p. 141. Enpir.

Prof. Owen on the Phascolotherium. 221

mammalia to which the remains could be assigned, and that he
had found in the modification of the angle of the jaw, combined
with the form, structure and proportions of the teeth, sufficient
evidence to induce him to believe, that the Thylacotherium was a
marsupial quadruped.

Mr. Owen then recapitulated the objections against the mammi-
ferous nature of the Thylacotherian jaws from their supposed imperfect
state ; and repeated his former assertion, that they are in a condition
to enable these characters to be fully ascertained : he next reviewed
first the differences of opinion with respect to the actual structure
of the jaw; and, secondly, to the interpretation of admitted appear-
ances.

1. As respects the structure.—It has been asserted that the jaws
must belong to cold-blooded vertebrata, because the articular sur-
face is in the form of an entering angle; to which Mr. Owen
replies, that the articular surface is supported on a convex condyle,
which is met with in no other class of vertebrata except in the
mammalia. Again, it is asserted, that the teeth are all of an uni-
form structure, as in certain reptiles; but, on reference to the fos-
sils, Mr. Owen states, it will be found that such is not the case, and
that the actual difference in the structure of the teeth strongly sup-
ports the mammiferous theory of the fossils.

2. With respect to the argument founded on an interpretation of
structure, which really exists, the author showed, that the Thylaco-
therium, having eleven molars on each side of the lower jaw is no.
objection to its mammiferous nature, because among the placental
carnivora, the Canis Megalotis has constantly one more grinder on
each side of the lower jaw than the usual number; because the
Chrysochlore among the Insectivora has also eight instead of seven
molars in each ramus of the lower jaw; and the Myrmecobius,
among the Marsupialia, has nine molars on each side of the lower
jaw ; and because some of the insectivorous Armadillos and zoopha-
gous Cetacea offer still more numerous and reptile-like teeth, with all
the true and essential characters of the mammiferous class. The ob-
jection to the false molars having two fangs, Mr. Owen showed
was futile, as the greater number of the spurious molars in every
genus of the placental fere have two fangs, and the whole of them
in the Marsupialia. If the ascending ramus in the Stonesfield jaws
had been absent, and with it the evidence of their mammiferous
nature afforded by the condyloid, coronoid and angular processes,
Mr. Owen stated, that he conceived the teeth alone would have
given sufficient proof, especially in their double fangs, that the
fossils do belong to the highest class of animals.

In reply to the objections founded on the double fangs of the
Basilosaurus, Mr. Owen said, that the characters of that fossil not
having been fully given, it is doubtful to what class the animal be-
longed; and, in answer to the opinion, that certain sharks have
double fangs, he explained, that the widely bifurcate basis support-
ing the tooth of the shark, is no part of the actual tooth, but true
bone, and ossified parts of the jaw itself, to which the tooth is an-

222 Geological Society.

chylosed at one part, and the ligaments of connexion attached at the
other. The form, depth and position of the sockets of the teeth in
the Thylacothere are precisely similar to those in the small opos-
sums. The colour of the fossils, Mr. Owen said, could be no ob-
jection to those acquainted with the diversity in this respect, which
obtains in the fossil remains of Mammalia. Lastly, with respect to
the Thylacothere, the author stated, that the only trace of compound
structure is a mere vascular groove running along its lower margin,
and that a similar structure is present in the corresponding part of
the lower jaw of some species of opossum, of the Wombat, of the
Balena antarctica, and of the Myrmecobius, though the groove does
not reach so far forwards in this animal; and that a similar groove
is present near the lower margin, but on the outer side of the jaw,
in the Sorex Indicus.

Description of the Half Jaw of the Phascolotherium—This fossil
is a right ramus of the lower jaw, having its internal or mesial sur-
face exposed. It once formed the chief ornament of the private
collection of Mr. Broderip, by whom it has since been liberally pre-
sented to the British Museum. It was described by Mr. Broderip
in the Zoological Journal, and its distinction from the Thylacothe-
rium clearly pointed out. The condyle of the jaw is entire, stand-
ing in bold relief, and presents the same form and degree of con-
vexity as in the genera Didelphys and Dasyurus. In its being on a
level with the molar teeth, it corresponds with the marsupial
genera Dasyurus and Thylacynus as well as with the placental zoo-
phaga. The general form and proportions of the coronoid process
closely resemble those in zoophagous marsupials; but in the depth
and form of the entering notch, between the process and the condyle,
it corresponds most closely with the Thylacynus. Judging from the
fractured surface of the inwardly reflected angle, that part had an
extended oblique base, similar to the inflected angle of the Thy-
lacynus. In the Phascolotherium the flattened inferior surface
of the jaw, external to the fractured inflected angle, inclines out-
wards at an obtuse angle with the plane of the ascending ramus,
and not at an acute angle, as in the Thylacyne and Dasyurus ; but
this difference is not one which approximates the fossil in question
to any of the placental zoophaga; cn the contrary, it is in the
marsupial genus Phascolomys, where a precisely similar relation of
the inferior flattened base to the elevated plate of the ascending ramus
of the jaw is manifested. In the position of the dental foramen,
the Phascolothere, like the Thylacothere, differs from all zoophagous
marsupials, and the placental fere ; but in the Hypsiprymaus and
Phascolomys, marsupial herbivora, the orifice of the dental canal is
situated, as in the Stonesfield fossils, very near the vertical line
dropped from the last molar teeth. The form of the symphysis,
in the Phascolothere, cannot be truly determined; but Mr. Owen is
of opinion that it resemble the symphysis of the Didelphys more
than that of the Dasyurus or Thylacynus.

Mr. Owen agrees with Mr. Broderip in assigning four incisors to
each ramus of the lower jaw of the Phascolothere, as in the Didelphys;

Prof. Owen on the Phascolotherium. 223

but in their scattered arrangement they resemble the incisors of the
Myrmecobius. In the relative extent of the alveolar ridge occupied by
the grinders, and in the proportionsof the grinders to each other, espe-
cially the small size of the hindermost molar; the Phascolothere resem-
bles the Myrmecobius more than it does the Opossum, Dasyurus or
Thylacynus ; but in the form of the crown, the molars of the fossil re-
semble the Thylacynus more closely than any other genus of marsupials.
Inthe numberof the grinders the Phascolothere resembles the Opossum
and Thylacine, having four true and three false in each maxillary
ramus; but the molares veri of the fossil differ from those of the Opos-
sum and Thylacothere in wanting a pointed tubercle on the inner side
of the middle large tubercle, and in the same transverse line with it,
the place being occupied by a ridge which extends along the inner
side of the base of the crown of the true molars,and projects a little
beyond the anterior and posterior smaller cusps, giving the quin-
quecuspid appearance to the crown of the tooth. ‘This ridge,
which, in Phascolotherium, represents the inner cusps of the true
molars in Didelphys and Thylacotherium, is wanting in Thylacynus,
in which the true molars are more simple than in the Phascolo-
there, though hardly less distinguishable from the false molars.
In the second true molar of the Phascolothere, the internal ridge is
also obsolete at the base of the middle cusp, and this tooth presents
a close resemblance to the corresponding tooth in the Thylacine ;
but in the Thylacine the two posterior molars increase im size,
while in the Phascolothere they progressively diminish, as in the
Myrmecobius. As the outer sides of the grinders in the jaw of the
Phascolothere are imbedded in the matrix, we cannot be sure that
there is not a smaller cuspidated ridge sloping down towards that
side, as in the crowns of the teeth of the Myrmecobius. But,
assuming that all the cusps of the teeth of the Phascolothere are
exhibited in the fossil, still the crowns of these teeth resemble
those of the Thylacine more than they do those of any placental
Insectivora or Phoca, if even the form of the jaw permitted a com-
parison of it with that of any of the seal tribe. Connecting then the
close resemblance which the molar teeth of the Phascolotherium bear to
those of the Thylacynus with the similiarities of the ascending ramus
of the jaw, Mr. Owen is of opinion that the Stonesfield fossil was
nearly allied to Thylacynus, and that its position in the marsupial
series is between Thylacynus and Didelphys. With respect to the
supposed compound structure of the jaw of the Phascolotherium,
Mr. Owen is of opinion that, of the two linear impressions which have
been mistaken for harmonie or toothless sutures, one, a faint shallow
linear impression continued from between the antepenultimate and
penultimate molars obliquely downwards and backwards to the
foramen of the dental artery, is due to the pressure of a small
artery, and that the author possesses the jaw of a Didelphys Virgi-
niana which exhibits a similar groove in the same place. Moreover,
this groove in the Phascolothere does not occupy the same relative
position as any of the contiguous margins of the opercular and den-
tary pieces of a reptile’s jaw. The other impression in the jaw of

224 Geological Society.

the Phascolotherium is a deep groove continued from the anterior
extremity of the fractured base of the inflected angle obliquely
downwards to the broken surface of the anterior part of the jaw.
Whether this line be due to a vascular impression, or an accidental
fracture, is doubtful; but as the lower jaw of the Wombat presents an
impression in the precisely corresponding situation, and which is
undoubtedly due to the presence of an artery, Mr, Owen conceives
that this impression is also natural in the Phascolothere, but equally
unconnected with a compound structure of the jaw; for there is
not any suture in the compound jaw of a reptile which occupies a
corresponding situation.

The most numerous, the most characteristic, and the best marked
sutures in the compound jaws of areptile, are those which define the
limits of the coronoid, articular, angular, and surangular pieces, and
which arechiefly conspicuous on the inner side of the posterior part of
the jaw. Now the corresponding surface of the jaw of the Phascolo-
there is entire; yet the smallest trace of sutures, or of any indication
that the coronoid or articular processes were distinct pieces, cannot be
detected; these processes are clearly and indisputably continuous,
and confluent with the rest of the ramus of the jaw. So that
where sutures ought to be visible, if the jaw of the Phascolothere
were composite, there are none; and the hypothetical sutures that
are apparent do not agree in position with any of the real sutures
of an oviparous compound jaw.

Lastly, with reference to the philosophy of pronouncing judg-
ment on the saurian nature of the Stonesfield fossils from the
appearance of sutures, Mr. Owen offered one remark, the justness
of which, he said would be obvious alike to those who were, and
to those who were not, conversant with comparative anatomy. The
accumulative evidence of the true nature of the Stonesfield fossils,
afforded by the shape of the condyle, coronoid process, angle of the
jaw, different kinds of teeth, shape of their crowns, double fangs,
implantation in sockets,—the appearance, he repeated, presented
by these important particulars cannot be due to accident; while
those which favour the evidence of the compound structure of the
jaw may arise from accidental circumstances.

A paper was afterwards read, entitled ‘‘ Observations on the
Structure and Relations of the presumed Marsupial Remains from
the Stonesfield Oolite,’’ by William Ogilby, Esq., F.G.S.

These observations are intended by the author to embody only
the most prominent characters of the fossils, and those essential
points of structure in which they are necessarily related to the class
of mammifers or of reptiles respectively. For the sake of putting
the several points clearly and impartially, he arranged his observa-
tions under the two following heads :—

1. The relations of agreement which subsist between the fossils
in question and the corresponding bones of recent marsupials and
insectivora.

2. The characters in which the fossils differ from those families.
Mr. Ogilby confined his remarks to-marsupialia and insectivora,

Geological Society. 225

because it is to those families only of mammifers that the fossils
have been considered by anatomists to belong; and to the interior
surface of the jaw, as the exterior is not exhibited in any of the fossil
specimens,

1. In the general outline of the jaws, more especially in that of
the Didelphys (Phascolotherium) Bucklandii, the author states, there
is a very close resemblance to the jaw in recent insectivora and
insectivorous marsupials ; but he observes, that with respect to the
uniform curvature along the inferior margin, Cuvier has adduced
the same structure as distinctive of the Monitors, Iguanas, and other
true saurian reptiles, so that whatever support these modifications of
structure may give to the question respecting the marsupial nature
of the Stonesfield fossils, as compared with other groups of mammals,
they do not affect the previous question of their mammiferous na-
ture, as compared with reptiles and fishes. The fossil jaws, Mr.
Ogilby says, agree with those of mammals, and differ from those of
all recent reptiles, in not being prolonged backward behind the
articulating condyle ; a character in conjunction with the former
relation which would be, in this author’s opinion, well nigh incon-
trovertible, if it were absolutely exclusive ; but the extinct saurians,
the Pterodactyles, Ichthyosauri, and Plesiosauri, cotemporaries of the
Stonestfield fossils, differ from their recent congeners in this respect
and agree with mammals. Mr. Ogilby is of opinion that the con-
dyle is round both in D. Prevostii and D. Bucklandii, and is there-
fore a very strong point in favour of the mammiferous nature
of the jaws. The angular process, he says, is distinct in one speci-
men of D. Prevostii, and, though broken eff in the other, has left a
well-defined impression ; but that it agrees in position with the insec-
tivora, and not the marsupialia, being situated in the plane passing
through the coronoid process and the ramus of the jaw. In the
D. Bucklandii, he conceives, the process is entirely wanting; but
that there is a slight longitudinal ridge partially broken, which
might be mistaken for it, though placed at a considerable distance up
the jaw, or nearly on a level with the condyle, and not at the
inferior angular rim of the jaw. He is therefore of opinion that the
D. Bucklandii cannot be properly associated either with the marsu-
pial or insectivorous mammals. The composition of the teeth, he
conceives, cannot be advanced successfully against the mammiferous
nature of the fossils, because animal matter preponderates over
mineral in the teeth of the great majority of the Insectivorous Cheir-
optera, as well as in those of the Myrmecobius, and other small marsu-
pials. In the jaw of the D. Prevostii, Mr. Ogilby cannot perceive
any appearance of a dentary canal, the fangs of the teeth, in his
opinion, almost reaching the inferior margin of the jaw, and being:
implanted completely in the bone ; but in the D. Bucklandii, he has
observed, towards the anterior extremity of the jaw, a hollow
space filled with foreign matter, and very like a dentary canal. The
double fangs of the teeth of D. Prevostii, and probably of D. Buck-
landii, he says, are strong points of agreement between the fossils
and mammifers in general; but that double roots necessarily indi-

Phil. Mag. 5. 3. Vol. 14. No. 88. March 1839. Q

226 Astronomical Society.

cate, not the mammiferous nature of the animal, but the compound
form of the crowns of the teeth.

2, With respect to the most prominent characters by which the
Stonesfield fossils are distinguished from recent mammals of the
insectivorous and marsupial families, Mr. Ogilby mentioned, first,
the position of the condyle, which is placed in the fossil jaws in a line
rather below the level of the crowns of the teeth; and he stated
that the condyle not being elevated above the line in the Dasyurus |
Ursinus and Thylacinus Harrisii, is not a valid argument, because
those marsupials are carnivorous. The 2nd point urged by the
author against the opinion, that the fossils belonged to insectivorous
or marsupial mammifers, is in the nature and arrangement of
the teeth. The number of the molars, he conceives, is a second-
ary consideration ; but he is convinced that they cannot be separated
in the fossil jaws into true and false, as in mammalia; the great
length of the fangs, equal to at least three times the depth of the
crowns, he conceives, is a strong objection to the fossils being placed
in that class, as it is a character altogether peculiar and unexampled
among mammals; the form of the teeth also, he stated, cannot be
justly compared to that of any known species of marsupial or insec-
tivorous mammifer, being, in the author’s opinion, simply tricuspid,
and without any appearance of interior lobes. As to the canines
and incisors, Mr. Ogilby said, that the tooth in D, Bucklandii,
which has been called a canine, is not larger than some of the pre-
sumed incisors, and that all of them are so widely separated as to
occupy full five-twelfths of the entire dental line, whilst in the
Dasyurus viverrinus, and other species of insectivorous marsupials,
they occupy one-fifth part of the same space. Their being arranged
longitudinally in the same line with the molars, he conceives, is
another objection, because, among all mammals, the incisors occupy
the front of the jaw, and stand at right angles to the line of the
molars. With respect to the supposed compound structure of the
jaw, Mr. Ogilby offered no formal opinion, but contented himself
with simply stating the appearances; he, nevertheless, objected to
the grooves being considered the impression of blood vessels, though
he admitted that the form of the jaws is altogether different from
that of any known reptile or fish.

From a due consideration of the whole of the evidence, Mr.
Ogilby stated, in conclusion, that the fossils present so many import-
ant and distinctive characters in common with mammals on the
one hand, and cold-blooded animals on the other, that he does not
think naturalists are justified at present in pronouncing definitively
to which class the fossils really belong.

ASTRONOMICAL SOCIETY.
Dec. 14, 1888.—The following communications were read :—
I. Extract of a letter from Professor Bessel to Sir J. Herschel,
Bart., dated Konigsberg, Noy. 4, 1838*.

* Prof. Bessel’s letter on the parallax of « Cygni, to which the above ex-

Astronomical Society. 227

The means which I have employed to ascertain the effect of tem-
perature upon the measures by the heliometer, consist in observing
such of the stars of the Pleiades as are visible in the coldest winter,
by night, and in the warmest summer, by day. ‘Soon after the in-
strument was set up (in November and December 1829) I made a
series of observations of this kind, and repeated them in the summer
of 1830. From these I found the value of one reyolution of the
screw in the temperature f of Fahrenheit,

= 52/-91788 —( f — 49-2)0”-0004493 (Astro, Nach. No. 189, p. 418).

Further observations, however, have reduced the value of the last
term of the formula to 0'-0003912: this latter value is that which
I have employed in the reduction of the observations of 61 Cygni.
If this correction of the measures had been altogether neglected, the
result, which the star a affords, would have been in error about
0-06 ; but, in the case of the star 6, the effect would be altogether
inappreciable, since the maximum of the influence in question takes
place at that time of the year in which the parallax disappears. I
owe this explanation to you, since you have inquired expressly as
to this point; and, moreover, it could not be indifferent to me that
an astronomer to whose opinion I attach so much importance, should
not only be partially, but also thoroughly, satisfied as to the paral-
jax of 61 Cygni.

After nine years’ service, I resolved to take the heliometer to
pieces, in order to examine anew all the parts of the mechanism of
this very ponderous instrument ; and to provide, in time, against any
damage it may have sustained. The whole, however, is so solidly
and durably constructed, that it has been found to need scarcely any
repair. Ihave taken the opportunity of making some alterations
for the greater convenience of the observer. ‘The instrument, on
account of these circumstances, has been nearly three weeks out of
use ; it is now, however, again in a fit state for observation.

I am particularly anxious to obtain your physical observations of
the comet. Struve has lately communicated to me his own, which
differ considerably from mine, as they show the tail defined, whereas

it appeared to me undefined ; pie: Struve, Le Bessel. In other

respects these observations are similar to mine, except that they go
more into detail. It appears that 1am the only one who has had
the good fortune to be able to follow the comet during an entire
night, in which the motion of the tail fell in its own direction. Ac-
cording to the letter which I had the pleasure to receive from you,
the comet seems latterly to have lost its tail altogether ; at least you
mention only the complete definition of the disc, which also [ con-
sider a very important observation.

At the approaching disappearance of Saturn’s ring, sufficiently

tract relates, will be found in our number for January, present volume,
p. 68.—Epir.
Q2

228 Astronomical Society.

powerful telescopes will probably be employed to show all the satel-
lites of the planet. I believe that large reflecting telescopes will
begin to supersede achromatic ones; at least, I have no doubt they
are capable of greater perfection. They can be made with mathe-
matical precision, which is not the case with achromatic telescopes.
I think, also, that opticians would have devoted their attention to
them in preference, if they had not been discouraged by their more
rapid destructibility. If the method of making an indestructible
metallic surface could be discovered, I should no longer doubt of a
still further perfection of the reflecting telescope. Could not hard
steel be made available? and would it not, if proper care was taken
of it, be less destructible than the common metallic reflector ?

Il. Errors of Heliocentric Longitude and Ecliptic Polar Distance
of the planet Venus, computed from the Tabular Errors of R. A. and
N. P. D., given in the Cambridge Observations of 1886. By the
Rev. R. Main.

Having been engaged in correcting the Elements of the Orbit of
Venus, it occurred to Mr. Main that the reduction of the Tabular
Errors of R. A. and N.P. D., derived from the Cambridge Observa-
tions of 1836, to errors of Heliocentric Longitudes and Ec. P.D.,
would form a desirable supplement to his papers.

He has added the equations which arise for the corrections of the
Node and Inclination of the Orbit; and it is his intention to form
those for the corrections of the four remaining elements.

He has used Mr. Airy’s formulz contained in the tenth volume of
the Society’s Memoirs, and divided the observations into groups of
about the same length; applying the same corrections to the Right
Ascensions for the Error of the Equinoctial Point.

The general agreement between the errors, and those given in the
Greenwich Observations for 1836, shows the goodness of the obser-
vations, and gives additional confidence in the results to be derived
from them.

The errors of the tables are then given, and equations for correct-
ing the elements.

III. A Catalogue of 726 Stars, reduced to the year 1830, and de-
duced from the Observations made at Cambridge in the years 1828-
1835. By G.B. Airy, Esq., Astronomer Royal.

The state of reduction in which the places of the stars had been
published in each of the annual volumes of the Cambridge Observa-
tions, left little to be done for the formation of this catalogue, ex-
cept the combination of the results of the different years. This was
done by applying to the mean of each year’s results the annual va-
riation in the catalogue of this Society (except for stars near the
pole), so as to bring the places up to Jan. 1, 1830; and then taking
the mean of the different results for 1830, giving to each year a
weight proportioned to the number of observations. Special me-
thods of reducing some of the observations are fully explained in the
preface, to which it is not requisite here to allude further; and a list
of the principal discordances are subjoined, as well as of some of the
observations that have been omitted in the reductions.

Astronomical Society. 229

IV. Extract of a letter from Mr. Henderson to Mr. Baily, rela-
tive to the late Annular Eclipse of the Sun on May 15, 1836.

After correcting the places of the sun and moon, and their semi-
diameters, by the quantities mentioned in my last letter, I computed
the beginning and end of the eclipse, and of the annulus; and
I annex the computed times of these phenomena, and also the ob-
served.

Computed Observed

sid. Time. Time.

i ms ie m 8
IBEPINNIND GEECHDSC) ves vases educwonscncasenssecetondsa cvs 5 6 9:2 not observed.

At formation of annulus,
First appearance of detached luminous portions of

RUMP) eu reece acs Sdsat. hee accncdewcseccndedneseeteuses 6 30 41°1
Internal contact of sun and MOON........sseeceeceeeeeees 6 30 46°2
Annulus completely formed by disappearance of

IPAM NANDOESic sonescscssinesac-cxcadiscsccavarteeaccees) ocece 6 30 501

At dissolution of annulus,

Annulus broken by appearance of black spots......... 6 34 33:0
Internal contact of sun and MOON........e.eeceeceeseeeee 6 34 40°3
Disappearance of detached luminous portions of

BETSPIUINOM. Jaa ses eavsder ect cscetioeedscestescae setae oreec ot 6 34 44:0
Brees aS Oa Ne) AL a EE er eee

It thus appears that the true internal contacts happened between
the moments when the beads of light were observed to appear and
disappear, and when the black spots disappeared and appeared. At
the formation of the annulus, when the beads appeared, 1/6 of the
moon (a segment of that mazimum breadth) seems to have been be-
yond the sun’s disc ; and when the black spots disappeared, the an-
nulus was 1'"1 in breadth, where least. ‘This agrees with the ap-
pearance observed, “that the annulus was seen completely formed
of sensible breadth at the narrowest part.” Again, at the dissolu-
tion of the annulus, when the black spots appeared, it is found that
the least breadth of the ring was 2!'-3, also agreeing with the actual
observation, that ‘‘ the annulus, being of sensible breadth, was sud-
denly broken ;” and when the beads disappeared, 1/2 of the moon
was beyond the sun’s disc. The same telescope was used for ob-
serving the formation and dissolution of the annulus, and for making
the observations from which the corrections of the elements have
been determined.

On applying the same corrections, I find that in latitude 55° 27! 30!
N. and longitude 10™ 12%,0 W. of Greenwich, the true internal con-
tacts were at

Observed by you at

Mean time. Mean time.
h. m. s. h. m.s.
3 0 33 i 0057;
5.3 47 3.) 5) 23
Duration =0 4 34 Duration = 0 4 26

I suspect that the longitude of your station is not well determined;
but, as a small error in the longitude will not sensibly affect the du-

230 Intelligence and Miscellaneous Articles.

ration of the annulus, I am inclined to believe that the times you
noted are those when the black spots disappeared and appeared.
You seem to have been in very nearly the line of the central eclipse,
as the least distance of the centres was only 1!’*.

V. A Letter from Mr. Lassell to the Rev. R. Sheepshanks, rela-
tive to Observations with a small Sextant.

The sextant, here alluded to, was made by Dollond, It is only
3 inches radius, divided to 20', and by vernier reading to 30”; but,
by means of the reading microscope, subdivisions may be estimated
to 10". The telescope magnifies 6 and 11 times; but the higher
power is generally used. The whole packs in a box 4°3 inches
square, and 2°7 inches deep. With this instrument Mr. Lassell
made a number of observations on various stars, both for the time
and latitude, for the express purpose of determining how near to the
truth he might be able to approximate by its means. The observa-
tions are given in detail, and the result at which Mr. Lassell arrives
is, that under ordinary circumstances the mean of one set of alti-
tudes east, and another west, would give the time truly within about
one second; and that a set of each, north and south, at something
like equal altitudes, would give the latitude within eight or ten
seconds. lb itd bey

FRIDAY-EVENING MEETINGS AT THE ROYAL INSTITUTION.

January 18th.—Mr. Faraday on the Gymnotus and Torpedo.
The subject included a general view of the nature and condition of
electric fishes, with the particular results which the speaker has
lately communicated to the Royal Society.

January 25th.—Mr. Woodward on the apparatus for the public
demonstration of the general laws and properties of polarized light.

February 1st.—Dr. Grant on the recent discoveries regarding
the structure and history of animalcules.

February 8th.—Mr. Parsey on natural perspective.

February 15th.—Mr. Faraday on Gurney’s oxy-oil, or Bude lamp
for lighthouses and other situations.

XXXIX. Intelligence and Miscellaneous Articles.
ON THE CHLORO-CHROMIC ACID OF DR. THOMSON.
To the Editors of the Philosophical Magazine and Journal.
GENTLEMEN,
N the number of your Journal for July 1838, (Lond. and Edinb.
Phil. Mag. vol. xiii. p. 78.) under the title of Bichromate of Per-
chloride of Chromium, there is an historical error which ought to be
corrected. This beautiful substance was not discovered by Berze-
lius but in 1824 by Dr. Thomson of Glasgow, and described in the
Phil. Trans. for 1827. It has since been examined by Unverdorben,
Wohler, Dumas, Rose, and Walter. The following are the formule
which have been deduced from their analyses :-—

* An abstract of Mr. Baily’s observations on this eclipse appeared in
Lond. and Edinb. Phil. Mag. vol. x. p. 230.—Ep1r.

Intelligence and Miscellaneous Articles. 231

Thomson.... Cr Cl: or CrO,z Cl

Wohler...... Cr Cl; + 2CrOgz

Dumas...... Cr Cl,

Gse we ate oe Cr Cl + 2Cr O,1
There is an error also in the description of the properties of this
compound. Chloro-chromic acid does not detonate with phosphorus
unless that substance is moistened with water.

Your obedient servant,
June 29th, 1838. ——————— le
FALL OF METEORITES IN SOUTH AFRICA.

“T have forwarded to Sir J. Herschel a splendid specimen of a
meteor that exploded about 100 miles from Cape Town. The whole
mass could not be less than 4 cubic feet. A pretty sort of solidifi-
cation if it took place in our atmosphere ; such an origin is scarcely
conceivable. You will no doubt hear of it from him, together with
its analysis*. We were at tea last Wednesday evening (6" 37™)
broad daylight, when a meteor passed over the Observatory from
the N.W., and appeared to fall a few hundred yards in front. We
simultaneously jumped up. It was as brilliant as a full moon, but
a more pungent light; no noise. ‘The image of the window-sash
upon the opposite wall was as bright as if the sun shone in front
of it. The apparent size of the body was equal to that of a full
moon.”— Extract from a letter (November 25, 1838) from Thomas
Maclear, Cape Town, to Captain Smyth, R.N.

ALLOXAN}.

The erythric acid of Brugnatelli; rediscovered by Wohler and
Liebig. One of the products of the decomposition of uric acid
by nitric acid. One part of dry uric acid is added in successive por-
tions to 4 parts of nitric acid of sp. gr. 1-45 to 1°5, by which it is
dissolved with effervescence and the production of heat; the pro-
duction of a high temperature must be avoided as much as possible
by artificial cooling, and by adding the uric acid slowly. Small
granular crystals of a strong lustre are thus formed, and by degrees
the whole liquid is converted into a solid mass. This should then
be placed in a glass funnel; and after the fluid parts have thus
drained off, it should be spread upon a porous tile, where it is ren-
dered perfectly dry. It is purified by solution in hot water and re-
crystallization.

Properties. —On the cooling of a warm but not perfectly saturated
solution of alloxan, it is obtained in large colourless and transparent
crystals of the right prismatic system, and of a strong adamantine
lustre ; these crystals effloresce rapidly, losing 25 per cent. =6 eq.
water, and are converted when gently warmed, with the loss of

* Froma letter received, together with a specimen of the meteorites, from
Mr. George Thompson, of Cape Town, the date of the fall appears to have
been October 13, 1838.—E.W.B.

} This and the seven following notices are copied from Part ILI. of the
late Dr. Turner's Chemistry, recently published by Professor Liebig and

Dr. Wilton Turner.

232 Intelligence and Miscellaneous Articles.

water, into anhydrous alloxan. If a hot saturated solution be al-
lowed to crystallize in a warm place, anhydrous alloxan is deposited
directly from the solution in oblique prisms, on the extremities
of which truncated rhomboidal octohedrons are seen. It is very
soluble in water, has a disagreeable odour, and a slightly saline
astringent taste, reddens vegetable colours, and causes a purple stain
on the skin. Treated with alkalies, alloxanic acid is formed; but on
boiling it is decomposed into urea and mesoxalic acid. Heated
with peroxide of lead it is decomposed into urea and carbonate of
lead, with which a few traces of oxalate of lead are mixed. When
brought into contact with zinc and hydrochloric acid, with chloride
of zinc or sulphuretted hydrogen, alloxantin is produced; it is de-
composed by free ammonia into mykomelinic acid, by nitric acid
into parabanic acid, by sulphuric and hydrochloric acids into allox-
antin, by sulphurous acid and ammonia into thionurate of ammonia,
with alloxantin and ammonia into murexid. With a protosalt of iron
and an alkali, it forms an indigo-blue solution. Does not unite
without decomposition with the metallic oxides.

The formation of alloxan and the other products which arise at
the same time, is dependent upon two perfectly independent decom-
positions ; namely, upon the conversion of cyanoxalic acid into
alloxan, and upon the mutual decomposition of urea and hyponitrous
acid. To 1 eq. of cyanoxalic acid are added the elements of 4 eq.
water, and 2 eq. oxygen from 1 eq. nitric acid, by which 1 eq. al-
loxan and 1 eq. hyponitrous acid are formed. The latter combines
with the ammonia of the urea, and liberates cyanic acid; the hy-
ponitrite of ammonia is decomposed by heat into nitrogen and water,
and the cyanic acid with water is resolved into carbonic acid and
ammonia, which unites with the free nitric acid.

Cyanoxalic acid=CgNo Og

4 eq. water H,0,
2 eq. oxygen Oz
1 eq. alloxan = CyN2H4Oj0
Urea =C,N.H,40,
Hyponitrous acid= N 03 |
C,N3H4,O;=C,04+ Nj+ NH;+ HO.

Carbonic acid. Nitrogen. Ammonia. Water.

It frequently happens that on dissolving the impure alloxan, for
the purpose of purifying by a second crystallization, a portion of
alloxantin is obtained ; it may be easily separated from the allox-
antin by cold water.

ALLOXANIC ACID.

Discovered by Wohler and Liebig. Produced by the decomposi-
tion of alloxan by alkalies. It is prepared by decomposing alloxan-
ate of baryta by sulphuric acid. A strongly acid fluid is obtained,
which by gentle evaporation crystallizes in radiated groups of aci-
cular crystals ; it is a-bibasic acid, dissolves zinc with the evolution
of hydrogen, is unchanged by sulphuretted hydrogen, and precipi-
tates the salts of silver, baryta, and lime. The anhydrous alloxanic

Intelligence and Miscellaneous Articles. 233

acid contains the constituents of half an equivalent of alloxan minus
1 eq. water.
Its formula is C,N.H,O, + 2 eq.

ALLOXANIC ACID AND METALLIC OXIDES.

Alloxanic acid neutralizes the alkalies perfectly, decomposes the
carbonates, and forms, when neutralized by ammonia, with the salts
of silver a white precipitate, which by boiling becomes first yellow
and then black, the change being accompanied by a rapid efferves-
cence; treated with ammonia in excess, it produces white gelatinous
precipitates with the salts of lime, strontia, and baryta; but the
precipitate is redissolved by a large excess of water, and readily by
an acid. ‘The solutions of the neutral alloxanate of lime, strontia,
and baryta, become turbid when boiled, the bases are precipitated,
and urea and mesoxalic acid are formed.

Allovanate of Baryta —Prepared by adding barytic water to an
aqueous solution of alloxan at the temperature of 140°; on each
addition a white precipitate is formed, but it is redissolved by stir-
ring ; the barytic water is added in successive portions till the pre-
cipitate is permanent, when the solution is allowed to cool. The
mother-liquor separated from the crystals is again to be heated and
treated with barytic water as before, and this should be repeated as
long as crystals are obtained.

Short‘ transparent needles, or mother-of-pearl scales, which at
212° become milk-white and lose 3 eq. water; at 300° they are an-
hydrous ; they are sparingly soluble in cold, but more freely in hot
water; exposed to a red heat they leave a mixture of carbonate of
baryta and cyanuret of barium.

Its formula is C,NeH20,,2BaO + 8 aq.

Alloxanate of Silver.—A white insoluble powder, which produces
a slight explosion when heated ; the residue after being heated to
redness yields cyanic acid and metallic silver.

Its formula is C,N,H,O, + 2AgO.

MESOXALIC ACID.

When a saturated solution of alloxanate of baryta or strontia is
heated to the boiling point, a precipitate falls consisting of the car-
bonate, mesoxalate, and alloxanate of baryta or strontia. The so-
lution, on evaporation, yields a crystalline crust, from which urea is
separated by treating it with alcohol, and mesoxalate of baryta re-
mains. If a solution of alloxan be added, drop by drop, to a boiling
solution of acetate of lead, a very heavy granular precipitate of mes-
oxalate of lead is formed, and urea remains as the only other product
in the solution. The mesoxalic acid may be obtained by decom-
posing this lead salt by sulphuric acid ; it is a strongly acid solution,
reddens vegetable colours, and forms, like the alloxanic acid, on the
addition of ammonia, precipitates with the salts of baryta and lime,
which are soluble in acids and a large excess of water; it may be
boiled and evaporated without change. Its action on the salts of

234 Intelligence and Miscellaneous Articles.

silver is characteristic; it forms with them, after being neutralized
by ammonia, a yellow precipitate, which on being gently heated is
reduced to the metal with a rapid effervescence. ‘The above-men-
tioned lead salt yields, on analysis, 80°4 per cent. of oxide of lead ;
it contains a slight admixture of a substance containing nitrogen,
probably cyanate or cyanurate of lead, from which it cannot be per-
fectly purified. The composition of the lead salt is very probably
expressed by the formula C,O, + 2PbO, in which case its formation
from alloxan and alloxanic acid admits of a ready explanation. From
1 eq. alloxan 1 eq. urea is separated, by which 2 eq. of anhydrous
mesoxalic acid is left.

1 eq. alloxan == OEM Oy
—1 eq. urea On INerin Gs
=2 eq. mesoxalic acid=C, an

The above-mentioned mesoxalate of baryta contains 56 per cent.
of baryta, from which its constitution is probably represented by the

formula C,O, + {Ho.

MYKOMELINIC ACID.

Discovered by Wohler and Liebig. Product of the decomposition
of alloxan by ammonia. It is prepared by heating to 212 a solution
of alloxan with an excess of ammonia, then neutralizing with an
excess of dilute sulphuric acid and boiling for a few minutes. The
mykomelinic acid falls as a yellow gelatinous precipitate, which
dries to a yellow porous powder; it is with difficulty dissolved by
cold, but more readily by hot water; the solution has a distinctly
acid reaction; it decomposes the carbonated alkalies and is easily
dissolved by the caustic alkalies, but on being boiled with them is
decomposed with the evolution of ammonia ; it forms, with the oxide
of silver, a yellow compound, which is insoluble in water. It is
produced by the decomposition of 1 eq. alloxan and 2 eq. ammonia
into 1 eq. mykomelinic acid and 5 eq. water.

Its formula is probably C,N,H,O;.

PARABANIC ACID.

Discovered by Wohler and Liebig. Product of the decomposi-
tion of uric acid and alloxan by nitric acid. Prepared by treating
1 part of uric acid, or 1 part of alloxan, in 8 parts of pretty strong
nitric acid, evaporating to the consistence of a syrup, and allowing
it to stand for some time, when it yields colourless crystals which
may be purified by a second crystallization. :

Properties.—Colourless, transparent, thin, hexagonal prisms ; has
a strong acid taste, very similar to that of oxalic acid; is very so-
luble in water, does not effloresce either in the air or in a warm
room; fuses if heated, when a portion sublimes unchanged, but an-
other part decomposes with the evolution of hydrocyanic acid. The
cold solution neutralized by ammonia produces a white precipitate

Intelligence and Miscellaneous Articles. 235

in the salts of silver, which contains 70°62 per cent. of the oxide ;
when treated with ammonia it is converted into oxaluric acid.

It is formed by the decomposition of 1 eq. of uric acid, which, by
the addition of 2 eq. of water and 4 eq. oxygen from the nitric acid,
is resolved into 2 eq. carbonic acid, 1 eq. parbanic acid, and 1 eq.
urea; the latter is decomposed as before-mentioned by the hyponi-
trous acid. One eq. alloxan with 2 eq. oxygen is solved into 2 eq.
carbonic acid, 4 eq. water, and 1 eq. parabanic acid.

The formula of the crystalline acid is C;N,O, + 2 aq.

OXALURIC ACID.

Discovered by Wohler and Liebig. Produced by the decompo-
sition of parabanic acid. Prepared by adding dilute sulphuric or
hydrochloric acid to a saturated solution of oxalurate of ammonia
in hot water, and rapidly cooling the mixture when the oxaluric
acid falls as a white crystalline powder; this should be washed with
cold water as long as the washing, when neutralized by ammonia,
causes with the salts of lime a precipitate which is perfectly redis-
solved by heat, or by an additional quantity of water. It is a white,
or slightly yellow crystalline powder of an acid taste, reddens the
vegetable colours, and, when neutralized by ammonia, forms with
silver salts a white precipitate which is perfectly redissolved by
boiling. By boiling in water it is completely decomposed into free
oxalic acid and oxalate of urea. The oxaluric acid is formed by the
addition of 2 eq. water to the constituents of the parabanic acid.
It contains further the elements of 2 equivalents of oxalic acid and
1 eq. urea; it may be considered as uric acid in which the cyan-
oxalic acid has been replaced by the oxalic acid.

Its formula is C,N,H,O, + aq.

Oxalurate of Ammonia.—This salt may be formed by heating a
solution of parabanic acid with ammonia, or more advantageously
by treating a recently prepared solution of uric acid in dilute nitric
acid with an excess of ammonia and evaporating. The liquid ac-
quires at first a purple colour, which disappears during the evapo-
ration, and if allowed to cool when arrived at a certain degree of
concentration, it deposits radiated groups of hard acicular yellow
crystals; they are obtained colourless by charcoal and recrystal-
lization.

The oxalurate of ammonia crystallizes in radiated groups of fine
acicular crystals, which have a silky lustre, and are readily dissolved
by hot, but with difficulty by cold water; the solution has no re-
action on vegetable colours, and may be boiled and evaporated with-
out change; the dry salt loses no weight at 250°, but at a higher
temperature it is decomposed with the rapid evolution of hydrocya-
nic acid. Acids separate from a concentrated solution the oxaluric
acid as a crystalline powder.

Its formula is NH,O+C,N,H,O,.

OXALURIC ACID AND METALLIC OXIDES.
The oxaluric acid forms with the alkalies very soluble, but with

236 Intelligence and Miscellaneous Articles.

the alkaline earth sparingly soluble salts. If concentrated solutions
of oxalurate of ammonia, chloride of calcium or barium be mixed
with each other, after standing some time, brilliant transparent scales
or needles of oxalurate of baryta or lime will be deposited; a solu-
tion of the latter in water when treated with an excess of ammonia
gives a basic salt in the form of a transparent gelatinous precipitate,
which is redissolved by a large quantity of water.

Oxalurate of Silver.—This salt is obtained by mixing boiling so-
lutions of oxalurate of ammonia and nitrate of silver, and is depo-
sited as the solution cools in long anhydrous needles of a silky
lustre; these are decomposed at a high temperature without ex-
plosion.

Its formula is AgO + C,;N,H,O.-.

PNEUMATIC TELEGRAPH.

A pneumatic telegraph has been invented by Mr.S. Crosley, an ope-
rative model of which is preparing for exhibition at the Polytechnic
Institution. Atmospheric air is the conducting agent employed in its
operation. The air is isolated by a tube extending from one station to
another; each extremity of the tube being connected with a vessel con-
taining a small volume of air in direct communication with the air in
the tube. This vessel is employed as a reservoir to compensate for
any increase or diminution which must necessarily arise from compres-
sion, or from changes in the temperature of the air, and for sup-
plying any casual loss by leakage; the vessel must, therefore, be
capable of enlargement and contraction in its capacity, after the
manner of bellows, or as a gas-holder, by immersion in water, so as
to maintain, uniformly, any particular degree of compression which
may be given to it.

It will be evident to every one acquainted with the physical pro-
perties of atmospheric air, that if any certain degree of compression
be produced and maintained in the reservoir, at one station, equili-
brium will rapidiy succeed, and the same degree of compression will
extend to the opposite station, where it will become visible to an
observer by means of a pressure Index.

Thus, with ten weights producing ten different degrees of com-
pression, distinguished from each other numerically, and having a
pressure index at the opposite station, marked by corresponding
figures, any telegraphic numbers may be transmitted, referring in
the usual way to a code of signals, which may be adapted to various
purposes and to any language. The only manipulation is that of
placing a weight of the required figure upon the collapsing vessel at
either station, and the same figure will be represented by the index
at the opposite station.

Previously to making a signal, the attention of the person, whose
duty it is to observe it, is arrested by means of a preparatory signal.

The communications between one extremity and the other may
be made known at intermediate stations, by connecting with the air
tube, indexes corresponding with those at the extremities; but in

Intelligence and Miscellaneous Articles. 237

order to avoid the necessity for additional sounding apparatus, which
would retard the communications between the extremities, it would
be necessary to limit such intermediate communications to stated
periods, so that an observer might be in attendance.

A trial was made with a tube of one inch in diameter, very nearly
two miles in length, returning upon itself, so that both ends of the
tube were brought to one place :—the compression applied at one
end, was equal to a column of seven inches of water; and the effect
on the index at the other end, appeared in fifteen seconds of time.

Laws have been propounded by eminent men on the expenditure
of aeriform fluids through conduit pipes, and of the resistance of
the pipes; but these are not strictly applicable tc the present ques-
tion. Under all circumstances, it seems desirable that experiments
on a practical scale, at extended distances, should be resorted to,

as the most satisfactory guide, for carrying into effect telegraphic
communications of this kind.

METHOD OF DISTINGUISHING TRAP FROM BASALT.

Mons. H. Braconnot finds that these rocks may be distinguished by
subjecting them to distillation; the trap always yields an empyreu-
matic ammoniacal product, which restores the colour of litmus paper
reddened by an acid, whereas basalt produces no such effect; and he
presumes that the organic matter which had existed in the materials
of the basalt was destroyed by the. volcanic heat by which the rock was
produced; whereas he conceives trap to have been formed in water,
under the influence of a moderate temperature, insufficient to de-
stroy the organic matter which was contained in the debris from
which it was formed. ‘The trap was selected from various places,
and of unquestionable nature; and the basalt was that of Clermont,
in Auvergne. M. Braconnot has also found that various granites
yield ammonia when heated ; and the same effect was produced by
serpentine and porphyry; but the gneiss of Freiberg, in Saxony,
yielded an acid, which appeared to be the hydro-fluoric. Many
other rocks of various kinds were subsequently found to yield am-
monia.—Annales de Chim. et de Phys., Jan. 1838.

ABSORPTION OF AZOTE BY PLANTS DURING VEGETATION.

M. Boussingault has determined by numerous experiments, made
with great care, that, while shooting, wheat and trefoil neither in-
crease nor diminish the portion of azote which analysis shows. them
to contain; and that during germination, these grains lose carbon,
hydrogen, and oxygen; and that each of these elements, as well as
the proportions in which the loss occurs, varies at different stages of
germination. It appears also, that during the cultivation of trefoil
in soil absolutely deprived of manure, and under the influence of air
and water only, this plant acquires carbon, hydrogen, oxygen, and
a quantity of azote, appreciable by analysis: wheat cultivated ex-
actly in the same circumstances, also takes from the air and water,
carbon, hydrogen, and oxygen; but analysis does not prove that it
has either lost or gained azote.—Jdid.

238 Intelligence and Miscellaneous Articles.

EXPLORATION OF THE INDIAN ARCHIPELAGO.

Much interest has of late been excited by the plan of exploring
the Indian Archipelago made public in the Journal of the Geogra-
phical Society by Mr. James Brooke, who has since sailed on his
adventurous and very meritorious undertaking. We deem it proper
at this juncture to recall attention to the circumstance that a valued
correspondent of one of the Editors of the Philosophical Magazine,
in a paper published in the Annals of Philosophy, N.S., vol. xi.
p- 178, urged on the Government and the public the importance of
that scientific survey of the Indian Islands, which the zeal and enter-
prise of a private individual have now induced him to undertake.
The paper is anonymous, and we do not feel at liberty therefore to
state the name of the writer, unless we receive his permission to do
so. But the views which are taken in it, are we conceive so just
and accurate, and bear so directly upon the objects of Mr. Brooke’s
expedition, and also on those of some others now contemplated, that
we think it highly worthy the perusal of our present readers.

Jan. 30, 1839, Saeed
ON THE INFLUENCE OF NATIVE MAGNESIA ON THE GERMINA-

TION, VEGETATION, AND FRUCTIFICATION OF VEGETABLES.

BY ANGELO ABBENE.

Among the various causes which produce barrenness in lands, has
been enumerated the presence of magnesia, because it had been ob-
served that the various magnesian soils are sterile. ‘This opinion
has begun to lose credit, since Bergmann, who examined the compo-
sition of fertile soils, considered magnesia as forming one of their
principal constituents.

Prof. Giobert has performed a number of experiments to inquire
into the action of native magnesia, which is found in numerous cul-
tivated soils. In the environs of Castellamonte and of Baldissero, this
substance is abundantly diffused in the soils cultivated with great
success, and which exhibit a vigorous vegetation. There are many di-
stricts in Piedmont and elsewhere, where the bi-carbonate of lime and
of magnesia is abundant in the cultivated lands, which produce beau-
tiful plants. Giobert concluded from these experiments ; Ist, that
native carbonated magnesia is not injurious to the various functions
of vegetables; 2nd, that on account of the solubility of magnesia in
an excess of carbonic acid this earth can exercise an action analogous
to that of lime; 3rd, that a magnesian soil may become fertile when
the necessary manure is employed.

From these facts naturally proceeds the conclusion, that if the
magnesia was dissolved in an excess of carbonic acid and water, and
had entered like the lime into the composition of the sap, it ought
to be found in the plants with the potash, lime, oxide of iron, &c,
M. Abbene has ascertained this by the analysis of the ashes of
plants which had grown in magnesiferous mixtures. Moreover, he
endeavoured to find, by comparative experiments, whether the in-
fluence of magnesia on vegetation is analogous to that of lime. The
following are the conclusions he arrives at: 1st, Native magnesia
is not only not injurious to germination, vegetation, and fructifica-
tion of plants, but on the contrary, appears to be favourable to these

Meteorological Observations. 239

functions. 2nd, Magnesia, being soluble in an excess of carbonic
acid, has on vegetation an action analogous to that of lime; and
when a soil contains magnesia not sufficiently carbonated, this de-
fect may be remedied by the addition of manure, which by its de-
composition furnishes the necessary quantity of carbonic acid; the
amelioration will be much more efficacious if the soil be frequently
disturbed, as then the air will better exercise its action. 3rd, When lime
and magnesia exist in arable lands, the former is absorbed in prefer-
ence by the plants on account of its greater affinity for carbonic acid.
4th, In barren magnesian lands, it is not to the magnesia that the
sterility must be attributed, but to the cohesive state of their parts,
to the want of manure, of clay, or of other composts, to the large
quantity of oxide of iron, &c. 5th, Barren magnesian soils may be
rendered fertile by means of caleariferous substances, as rubbish,
chalk, ashes, marl, &c., provided the other conditions be fulfilled. —
Journal de Pharmacie de Janvier, 1839.

METEOROLOGICAL OBSERVATIONS FOR JANUARY, 1839.

Chiswick.—Jan.1. Overcast. 2,3. Cloudy andfine. 4. Rain: clear. 5,
Clear and yery fine. 6, Overcast: sleet: rain at night, with wind increasing to
a hurricane. 7. Boisterous. 8. Clear: slightsnow. 9,10. Frosty. 11. Over-
cast: rain. 12. Very fine. 13. Cloudy and windy, with slight showers. 14,
Rain. 15. Very clear, 16. Fine, but cold. 17,18. Sharp frost: clear, 19.
Stormy and wet: clear at night, with aurora borealis. 20. Fine: rain. 21.
Rain. 22, Clearandcold. 23, Overcast and fine. 24. Hazy: fine. 25.
Fine. 26, Fine: slight snow. 27. Cloudy and cold. 28, Frosty : slight
snow at night. 29. Clear: snow. 30. Sharp frost: slightly overcast: stormy
with snow: tempestuous at night. 31. Snowing.

The hurricane, which commenced about 10 p.m., on the evening of the 6th,
although considered unusually violent in the neighbourhood of London, appears
to have done little damage, compared with the devastation occasioned a few
hours previous in Ireland and in the west and north of England. In those
parts of the kingdom forest trees that had withstood the storms of a century or
centuries were torn up in thousands on some estates. There was here a slight
frost in the morning ; snow and sleet during the day, and rain in the evening.
The wind was from south-east in the early part of the day, but towards night it
blew from south-west and west.—R. Thompson.

Boston.—Jan. 1. Cloudy, 2. Stormy. 3. Fine: stormy night. 4, Cloudy:
rain early a.m. 5. Fine. 6, Fine: snowr.m- 7. Stormy: blew a hurricane
allday, 8. Stormy. 9,10. Fine. 11. Cloudy; rain early a.m,: rain a.m.
12,13. Cloudy. 14. Fine. 15. Stormy. 16,17. Fine. 18, Fine: snow p.m.
19. Clondy: rain early a.m.: raine.m. 20. Cloudy: rainearlya.m. 21.
Rain. 22. Fine: snow early a.m. 23, 24. Cloudy. 25. Fine: raine.m. 26.
Cloudy: snow early a.m.: snowr.m. 27. Cloudy: raina.m. 28. Cloudy.
29. Fine: rain and snow y.m, 30. Fine: rainr.m. $1. Cloudy: large fall of
snow early a.M.: more snow in the day, with hail.

Applegarth Manse, Dum/ries-shire.—Jan. 1. High wind and sharp showers.
2. Generally clear: occasional showers. 9%. Very boisterous. 4. Calmed a
little: stormy r.m. 5. Wind strong: snow. 6. Frost and snow: rain p.m.
7. Fearful storm: rain and sleet. 8, More calm: more snow. 9. Frost: snow
lying three inches. 10. Thaw: snow melting. 11. Rain moderate: flood.
12. Moderate day: sunshine. 13. Frequent heavy showers. 14, Showery :
aurora borealis. 15. Frosty after a boisterous night. 16. Clear frost: wind
lulled. 17. Calm and frosty, and sunny. 18, Frost a.m.; rain at night. 19.
Temperate: heavy flood. 20. Shower a.m.: still mild. 21. Frost a.m.: in-
creasing vm. 22. Clear frost: overcast p.m, 23. Frost again: slight thaw r.m.
24, Thaw; a few drops of rain, 25, Fine day, without frost. 26, Fine frosty
day. 27. Calm and clear frost. 28. Frost: slight fall of snow. 29. Frost :

storm of snow. 30, Frost; snowand high wind. 1. Frost; still snowing:
nine inches deep,

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THE

LONDON anp EDINBURGH
PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.)

A PRT 1889:

XL. Classification of the Older Stratified Rocks of Devonshire
and Cornwall. By the Rev. Professor Sepawick, F.R.S.
F.G.S., and Roprerick Impry Muxcuison, Esq., F.R.S..
F.G.S.*

T was the general belief of geologists, when we commenced
our examination of Devonshire, in the summer of 1836,
that the larger portion of its area was occupied by greywacke
or transition rocks of high antiquity, from which the culm-
bearing strata of Bideford, and many other places in the
county, could not be separated. Having occupied ourselves
for some years in deciphering the relative age of the older
rocks of England and Wales, we were naturally anxious. to
apply to this county those principles of classification by which
the successive subdivisions of the Silurian, and (though much
more imperfectly) also of the Cambrian System, had been de-
termined ; for it seemed to us very anomalous, that the culm
beds of Devonshire, though stated to resemble those of the
coal field of Pembrokeshire, both in their mineral characters
and in their associated fossil plants, should be interpolated
among the most ancient greywacke rocks of the county. Mr.
De la Beche had, however, in a communication to the Geo-
logical Society, stated that such was their position; and he
completed an Ordnance geological map, in which all the culm
rocks, as well as all the so called greywacke rocks of Devon,
were represented under one uniform colour. This map we
purchased many months before we commenced our examina-
tion of Devonshire. An outlive of the results of this exa-
mination was laid before the British Association in the autumn
of the same year; and we exhibited a section from the north
coast to Dartmoor, (copied, though not quite correctly, in the
* Communicated by the Authors.

Phil. Mag. S. 3. Vol. 14. No. 89. April 1839. FP

242 ProfySedgwick and Mr. Murchison on the Classification

Athenzeurf,) in which we pointed out an ascending series of
ancient stratified rocks, the greater part then supposed to be-
long to the upper Cambrian, and a comparatively thin band to
the lower Silurian strata: and we further showed that the culm
measures of Devon, so far from being mere courses subordinate
to these older rocks, constituted, in tact, a vast basin or trough
of carbonaceous deposits, differing from the rocks on which
they rested, in mineral character and in organic remains. We
also exhibited a map in which the boundaries of this great car-
bonaceous trough were defined, with as much accuracy as the
short period of our examination permitted ; and we stated our
belief, that at least all the upper part of it was the equivalent
of the true coal measures. We further proved, that the granite
of Dartmoor had been protruded after the consolidation of the
culm or coal formation. Subsequently, we embodied these re-
sults with other details, not presented to the British Asso-
ciation, in a second memoir, read before the Geological Society
(June, 1837), in which we gave a short account of the structure
of South Devon; the different rocks of which we placed in
parallel with their equivalents in North Devon, referring them,
as well as we were able, to their types in other districts of Great
Britain.

Adhering strictly to our first view, viz. that the great over-
lying culm-bearing trough is the equivalent of the carbonife-
rous system; we proceed to point out the reasons which
induce us to make a material change in the classification and
equivalents of the older rocks of Devon and Cornwall.

North Deven.—In our previous communications we subdi-
vided the part of Devon which lies between the north coast
and the trough of culm deposits into five ascending mineral
masses, closely linked to, or passing into one another. From
its lithological character, from the ferruginous impressions of
stems of Encrinites, and the resemblance of certain casts of
shells (much distorted, however, by compression, and by lines
of slaty cleavage) to fossils of the Caradoc sandstone, we
placed the fifth group in the lower part of the Silurian system;
consequently the four inferior groups (though different in many
respects from anything we had ever seen among the older
rocks of Wales or Cumberland) necessarily fell into the upper
portion of the Cambrian system. Over all these groups came
the culm measures, and certainly without the intervention of
conglomerates or any manifest discordancy of position.

Since our memoirs were read, Mr. Weaver examined the
neighbourhood of Barnstaple ; and confirming our views as to
the age of the culm-measures, reported them to be uncon-
formable to the older rocks*. One of the authors, for the ex-

* Proceedings of the Geol. Soc. vol: il. —.

of the Older Stratified Rocks of Devonshire and Cornwall. 243

press purpose, among others, of inquiring into this point, re-
visited the country last summer, but was not able to discover
any discordance in the junction south of Barnstaple: on the
contrary, the culmiferous deposits seemed rather to be a con-
tinuous uninterrupted series, following the older rocks. Now,
if this be so, one of two things must follow. Either the culm
measures must be older, or the rocks of North Devon younger,
than we had at first supposed. The question then is this,
what is the evidence given by the fossils? The fossil plants
of the culm beds are undistinguishable from those of Pem-
brokeshire, the nearest coal field, while certain shells of the
black limestone, subordinate to the lower culm strata, prove
also to be undistinguishable from species which occur in the
true carboniferous system; and thus we have on fossil evi-
dence every ground for believing that our first view respecting
the culm measures was correct, and that they are the true
equivalents of the carboniferous system.

On re-examining, however, the collections of fossils we had
made among the strata which lie beneath the northern edge
of the culm field, we have seen reason to change our views
respecting the age of these older rocks.

In the uppermost of the five groups into which we pro-
visionally divided those rocks, we now find no unequivocal
lower Silurian fossils: for though two distorted casts have
much the appearance of shells of that date, there are other
and better preserved specimens, which approach so near to
species known in the carboniferous limestone, (Spzrifer cuspi-
datus and Spirifer attenuatus) as to be almost undistin-
guishable from them; and with these are found Leptene,
having somewhat the character of upper Silurian fossils, and
undescribed Terebratule, together with Trilobites, some of
entirely new forms, and others approaching to upper Silurian
types.

Below these slaty and calcareous strata near Barnstaple, a
part of which we first mistook, as above stated, for Caradoc
sandstone *, are the sandstones of Baggy Point, Marwood, and
Sloley, which we have elsewhere described in detail. In the
line of these are found certain fossil plants, specimens of which
were first sent to us by Major Harding, and others were laid
before the Geological Society by the Rev. D. Williams: some
of them are considered by Mr. Williams and Mr. De la Beche,
on the authority of Dr. Lindley, to be undistinguishable from

* The strong resemblance of the Caradoc sandstone, in consequence of
mineral character and the circular marks of crinoidal stems, to the sand-
stones of the lower shale of the Carboniferous limestone, and the probability
that this resemblance would lead to mistakes, has already been pointed out
by one of the authors. (Silurian System, pp. 384, 453.) .’

)

244 Prof. Sedgwick and Mr. Murchison on the Classification

plants of the carboniferous system. On the same line are fer-
ruginous bands, with casts of shells, communicated by Major
Harding, which strongly reminded us of forms in the old red
sandstone; one indeed being, as Mr. Sowerby thinks, identical
with the Bellerophon globatus of that system *.

In the next underlying groups of Morte Bay and lIfra-
combe, we have few well-preserved mollusca, but among them
is a very wide Spzrzfer and a spined Productus, approaching to
the carboniferous type, but unlike anything we know in the
Silurian or Cambrian rocks. Corals occur in parts of these
Ilfracombe groups, and among them is the Favosites poly-
morphu, a species most abundant in the upper Silurian rocks,
but not found in the lower.

Lastly, in the lowest group we perceived certain large heart-
shaped forms, quite unlike anything we had ever seen until we
afterwards detected the same in the collection of Mr. Hennah,
from the Plymouth limestone: and in the very lowest fossil
beds near Linton, we still perceived some of the same speci-
fic forms that occur near Barnstaple; which, though un-
described, may be pointed out as of characters intermediate
between those of the Silurian and carboniferous fossils, the
balance of evidence inclining rather to the younger of the two
types; there being few if any traces of the genus Orthis so emi-
nently characteristic of the Silurian system. ‘These evidences
all tend one way, and (confirmed as they are by the passage
of the bottom culm-measures) force us to believe that the old-
est rocks of North Devon are much younger than we at first
supposed: and coupling these with other proofs still more co-
gent from South Devon, we arrived at the conclusion which
we shall presently explain.

South Devon.—In the communication of 1837 to the Geo-
logical Society, we described several sections from the granite
of Dartmoor to the south coast of Devon, and (omitting the
altered slates) we divided the older stratified rocks into three
groups; the lowest, composed of slates, containing subordi-
nate bands of the Ashburton limestone, and ending in ascend-
ing order with the Plymouth and Torbay limestones, which
we considered to be identical; the second, composed of red
sandstone, with occasional subordinate beds of shale, &c.;
the third of soft non-fossiliferous schists, extending almost
to Start Point. These we considered (and we believe cor-
rectly) of the same age with the groups of North Devon;
and we attempted (without the aid of fossils) to bring them
into close comparison, by identifying the great deposits of red
sandstone of the two districts. ‘This identification of the sepa- -
vate groups we considered as merely provisional, “to be con-

* Murchison’s Silurian System, Pl. 3, 15.

of the Older Stratified Rocks of Devonshire and Cornwall. 245

firmed or rejected,” to use our own words, “by the examination
of the organic remains of the several groups.”

And here we may briefly allude to visits made by one of
the authors to different parts of this region, both before and
after the Bristol Meeting of the British Association, and sub-
sequent to the reading of our second memoir in London.
During the autumn of 1836, he traced the calcareous system
of South Devon into Cornwall, and followed it continuously
through the north of the Lizard into Mount’s Bay, and at Looe,
Fowey, and other places, found numerous organic remains
(not however yet described): in a former year, 1828, he had
traced the fossil slates of Tintagel into Padstow Bay, but had
then no time to carry his observations further south. Before the
autumn of 1836, Mr. De la Beche had worked out the structure
of the north side of Cornwall in great detail: and one of us,
informed by him of the existence of many other fossil localities,
examined the north Cornish coast; and concluded, in a paper
read at Cambridge in the winter of 1836-37, that the fossil-
zferous system on both sides of Cornwall was the same, and
therefore of the age, or nearly so, of the calcareous rocks of
South Devon. The same view was re-stated by us in the
paper read to the Geological Society. We still believe this
view to be correct, and hesitate not to class the calcareous
rocks of South Devon, and the fossiliferous slates of both
coasts of Cornwall, together.

Last.summer (1838), one of us paid a visit to Devon and
the neighbourhood of Launceston, for the purpose of ascertain-
ing the following points :

1. Whether the limestones of Newton Bushell could be
classed with the carboniferous or mountain limestone, an opi-
nion advanced by our friend Mr. Austen *, who drew that
conclusion from the forms of the numerous fossils he had
brought to light. 2. Whether the true culm-measures pass
under the Ashburton or Chudleigh limestone. 3. To ascer-
tain (especially after Mr. Weaver’s memoir) whether there was
any general discordancy of position between the culm-bearing
beds and the Cornish slates near Launceston. To each of
these questions his observations gave a negative. He was
confirmed in the views first stated by the authors in 1837,
concerning the relations of the limestone of Torbay to that of
Plymouth; and notwithstanding the many fossils of the New-
ton Bushell limestone resembling those of the carboniferous
system, its beds formed clearly a part of the group subordi-
nate to the great southern slate deposit. He saw no good
reason for thinking that the culm-measures pass under any

* See Proceedings of Geological Society.

246 Prof. Sedgwick and Mr. Murchison on the Classification

part of the limestones and slates of South Devon: and lastly,
he found near South Petherwin what appeared an unequivocal

passage between the fossiliferous slates and the overlying culm
series. From these facts it follows; Ist, that the fossiliferous
slates of Barnstaple, on the north side of the great culm
trough, must be nearly of the same age as those of South
Petherwin on its southern side; for certainly the inferior
strata of the culm series are the same, or very nearly the
same, at the two localities; 2nd, either that the culm series
was older, or the fossiliferous slate of North Cornwall newer
than we had supposed in our memoir of June 1837. Under

. these circumstances, it became doubly important to examine
large suites of fossils, before we could arrive at a correct con-
clusion as to the true place of the older Devonian strata in
the geological series *.

The most extensive collection of fossils which had been
made in South Devon, were from the Plymouth limestone by
the Rev. R. Hennah, and from the limestones of the neigh-
bourhood of Newton Bushell by Mr. Austen. The latter
was sent to the Geological Society to illustrate a memoir by
‘that gentleman; and the inspection of its contents convinced
Mr. Lonsdale, that few, if any, of the organic remains could
be strictly identified with species of the carboniferous limestone
to which Mr. Austen compared them; for although there
were some which had a close resemblance, still there were
many which bore the impress of a distinct type, while others,
particularly the corals, seemed to approach to certain forms
of the upper Silurian group; and hence Mr. Lonsdale was

* The fossils of South Petkerwin, from the first, presented a great diffi-
culty. One or two of them very nearly resembled mountain lime fossils;
and as a group they were not identical with any series we had before ex-
amined. ‘This induced one of the authors to join Mr. Austen (in July,
1837) in an excursion to that neighbourhood ; thinking it possible that the
South Petherwin limestone might form a part of the base of the culm-
measures. An unseasonable interruption compelled them, after two or
three days, to leave the country: but they ascertained, Ist, that the lime-
stone in question did not form a part of the culm series ; and 2nd, that the
fossils of South Petherwin, &c., were, as a group, nearly the same with the
fossils of South Devon; thus confirming a previous conclusion (drawn
from less perfect evidence), that the fossiliferous systems of South Devon
and of Cornwall were the same. They also found one junction (since
visited and sketched by Mr. De la Beche, Report, &c. p. 107.) in which the
culm beds appeared to rest unconformably on the older slates. This kind
of junction seems to form the exception and not the rule; and does not,
we think, invalidate the statement made above, Many such junctions might
indeed be found in the very heart of the culm-measures, where the beds
are all of one age. Such an appearance of want of conformity does not
therefore invalidate the fact of a true passage from the Petherwin slates
into the culm-measures.

of the Older Stratified Rocks of Devonshire and Cornwall. 247

induced to suggest to us (now more than a year ago), that
the South Devon rocks would be found to occupy an inter-
mediate place between the carboniferous and the Silurian sy-
stems. The collection of Mr. Hennah was unfortunately mis-
sent to Cambridge, and was only unpacked very recently:
but upon its examination (within these few weeks) by one
of the authors, in company with Professor Phillips and Mr.
James Sowerby, the same general results were arrived at;
namely, the existence of some fossils undistinguishable from
certain forms of the carboniferous limestone, and others from
those of the upper Silurian rocks, while many were entirely
new. Again, the corals of this limestone being examined by
Mr. Lonsdale, gave nearly the same results as those of Mr.
Austen.

After again examining our own collections, and looking to
the fossils of North Devon, South Devon and Cornwall as a
whole, we distinctly perceived that Mr. Lonsdale was right,
and that they must all belong to a system intermediate between
the two great systems (Silurian and Carboniferous) which had
so recently been shown to be entirely separated from each
other, both by their order of superposition and their imbedded
organic remains.

The publication, indeed, of the Silurian system and its nu-
merous fossils affords us a fixed term in the series of the older
rocks; and the previous labours of Professor Phillips and
others having made us acquainted with the organic remains
of the carboniferous system, we have now, for the first
time, the means of placing the Devonian groups in their true
order.

Without entering, on this occasion, into specific details, we
may state that the zoological groups of the Devonian rocks
are all of characters intermediate between those which mark
the Carboniferous and Silurian epochs. Thus, for example,
among the Cephalopoda, Goniatites have hitherto been con-
sidered as typical of the carboniferous system, while the re-
searches of one of the authors have shown that they never oc-
cur in the Silurian system. ‘They do, however, appear in
some of the older Devonian rocks; and, just as we should
expect, they are associated with analogues of an entirely new
type, the Endosiphonites*.

Again, there are many large and broad Spirifers in these
Devonian rocks, which closely approach to the forms of that
genus, so abundant in the carboniferous system. But this ge-
nus is feebly developed in the Silurian system, and the few spe-
cies that do occur are entirely unlike the large typical Spirifers
of the carboniferous sera; while the Orthis, or real Silurian

* See Trans. of the Cambridge Phil. Soc., vol. vi.

248 Prof. Sedgwick and Mr. Murchison on the Classification

Spirifer, is rarely if ever seen in Devonshire. The large round
spinose Producti are among the best-marked fossils of the car~
boniferous system. Now, the closest researches have not hitherto
brought to light the existence of one species having this cha-
racter in the Silurian system; while in Devonshire we find se-
veral associated with other species, which are analogous both
to the Silurian and carboniferous types. On the other hand,
the families and genera which predominate so much more in
the Silurian than in any other system, viz. T?zlobites and Or-
thoceratites, are here just of the intermediate character which
ought to be detected in deposits connecting that system with the

carboniferous. Some of them approach very closely to upper
Silurian species, if indeed there be not some undistinguish-
able; while others, particularly some of the Trilobites, are of
forms entirely different from any species hitherto found, either
in the Silurian or Carboniferous systems *.

In regard to the corals, Mr. Lonsdale informs us, that the
few which he can identify with published species (the most
abundant and certain being Favoszles polymorpha, Porites py-
rimorphis, and Stromatopora concentrica), belong to the upper
Silurian rocks; while there are several which are new and
undescribed. Again, the chain coral (Catenipora escharoides),
and many of the most remarkable Silurian types, are entirely
absent, nor has a single species common to the carboniferous
limestone been yet detected among the numerous polypifers
of South Devon.

Whether, in the sequel, we shall present to the public a
suite of engravings of all the undescribed Devonian and Corn-
ish fossils which we have collected, or which have been lent
to us, or shall consign them to Professor Phillips, to complete a
task for which he is so eminently qualified, and for which pur-
pose he is, we are glad to learn, to be employed by the Govern-
ment, is of little moment: but after such evidences, we have no
hesitation in putting forth our present classification, and in ac-
cepting, in the broadest form, the conclusions to which the ge-
neral view of these organic remains lead us, viz. that the oldest
slaty and arenaceous rocks of Devon and Cornwall are the equi-
valents of the old red sandstone. We also place, in the same
parallel, the older rocks of North Devon; being now fortified
in our conclusions by the evidence of the fossils, by the sec-
tions, and by the order of superposition; which indicates, on
both sides of the great carbonaceous trough, a passage down-
wards from the carboniferous system (the horizon of which

* Our friend M. de Verneuil acquaints us, that having examined a col-
lection of South Devon fossils sent to him by Mr. Austen, he is of opinion
that seven or eight of these shells are undistinguishable from fossils of the
Eifel, which he refers to tle Silurian system.

of the Older Stratified Rocks of Devonshire and Cornwall. 249

we consider as fixed,) into the Devonian equivalents of the
old red sandstone.

Under this view, the supposed difficulty arising out of the
existence of certain species of fossil plants, both in the carbo-
niferous system and ‘undisputed greywacke rocks*,” is at
once obviated : for the hard brown and greenish-grey micaceous
sandstones between Ilfracombe and Barnstaple, in which these
plants were discovered, are now placed in the upper part of
the old red sandstone, in which all true analogy would impel
us to look for the presence of some of the species of plants
common to the carboniferous epoch: and we are strengthened
in this conviction by the evidence of the shells on the same
line with these plants, among which is a species, as before
stated, of Bellerophon, identical, as far as casts can prove it,
with a shell figured from the cld red sandstone. In regard
to the organic remains of the old red sandstone, one of the
authors has indeed already published those forms which mark
its passage into the Silurian system. Aware of the enormous
thickness of this arenaceous series in the British Isles, and
having ascertained, to a certain extent, the peculiarity of its
fossils, particularly of its fishes, he proposed that it should be
considered “ a system,” intermediate between the Carbonife-
rous and Silurian systems f.

Whilst, however, he indicated the existence of certain
shells connecting the old red and Silurian systems, as well as
fossil fishes of very peculiar types in the former, he knew too
well that the greater mass of this vast system, particularly all
its upper members, contained no organic remains in the coun-
tries which he illustrated. In stating that “the strata (Carbo-
niferous and Silurian), so broadly distinguished by their or-
ganic remains, are separated by accumulations of enormous
thickness, and that the vast time occupied in their deposit ac-
counts satisfactorily for an almost entire change in the forms
of animal life ;” he also thus declared his anticipation con-
cerning the old red system: “ We are yet unprovided with
zoological links to connect the whole series, though I have no
doubt that such proofs will be hereafter discovered, and that
we shall then see in them as perfect evidences of a transition
between the old red and carboniferous rocks, as we now trace
from the Cambrian, through the Silurian into the old red sy-
stem §.”

* See De la Beche’s Report, p. 132, et seq.

t+ The plants were first observed by Major Harding and the Rev. D,
Williams.

t See Silurian System and Map.

§ Murchison’s Silurian System, p, 585.

No. 1.

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p. Granite.
g. Metamorphic Rocks ?

On the Older Stratified Rocks of Devonshire and Cornwall. 251

This hiatus is at last, in a great measure, filled up by the
fossils of the older rocks of Devon and Cornwall; and be-
lieving our views to be correct, we thus represent Devonshire
in two general sections from north to south.

In the higher of these the carboniferous trough is seen to
repose at each side on the slates and calcareous sandstones of
the old red system.

In the lower section the culm trough is flanked on the north
side only by the slaty rocks of the old red system, the granite
of Dartmoor having been protruded on its southern edge;
while the old red system reappears again in the southern part
of the county, terminated by a band of micaceo-chloritic schists,
which are perfectly parallel to the great disturbing axis of
Cornwall and Devon, and are probably altered or metamor-
phic strata.

In propounding these views, we have no desire to conceal
the error into which we were first led by trusting too much
to mineral characters. We unfortunately never gave, till very
lately, that attention to the organic remains which is indis-
pensable; but having been the first to point out, that nearly
one half of Devonshire is the equivalent of the carboniferous
rocks, we have no hesitation in going a step further, guided by
a closer inspection of the organic remains, and by the apparent
fact, that this carboniferous tract passes downwards into the
older system. It is not the first time that we (and we believe
we may say every practical geologist who has examined old
rocks) have been deceived in attributing too high antiquity to
strata having an antique lithological aspect and a slaty cleavage:
but the day is now passed, when such features, still less the
mere colour or composition of rocks, can be allowed to
lead to any true estimate of their age. We have red sand-
stones and conglomerates among the slates of the Cambrian
system; red and variegated sandstones abundant in the lower
Silurian rocks, as well as in the greatest red systems of our
islands, the one underlying, the other overlying, the carboni-
ferous deposits.

If it be contended that the old red sandstone of Great-
Britain, as hitherto understood, presents a more or less uni-
form character in its range from the Highlands of Scot-
land into South Wales, we must qualify the assertion. The
system assumes very great mineral varieties of aspect in dif-
ferent regions: in some tracts (parts of Scotland and’ Cum-
berland) it is usually composed of thick, coarse conglomerates,
while in others such masses give way to the finest laminated
sandstone and shale. In the north-western districts of the
Highlands, so completely was an eminent geologist* misled

* Dr. MacCulloch.

252 Prof. Sedgwick and Mr. Murchison on the Classification

by its lithological structure, that he classed a large portion of
it as primary sandstone,—an opinion which was afterwards cor-
rected by an examination of that region by ourselves*. Again,
it has fallen to us to show, that the black bituminous schists
of Caithness and the Orkneys form an integral part of the old
red sandstone: and what trace of lithological resemblance,
we would ask, is there between such rocks as these, which
occupy the north-eastern extremity of our island, and the
great masses of the same deposit which prevail in the form of
the variegated marls and concretionary limestones of Here-
fordshire and Brecknockshire? Passing from the latter di-
strict into Pembrokeshire, we perceive the old red sandstone
rapidly changing its aspect and composition. The concretion-
ary limestones disappear ; and a hard, brownish-red, schistose
rock replaces the soft marls, and large tracts are occupied by
yellow and grey, hard, siliceous sandstones.

As, therefore, such great lithological changes actually oc-
cur in continuous strata within such a limited area, why may
we not believe (particularly when we have strong collateral
reasons for doing so depending both on fossils and sections, )
that the older fossiliferous rocks of Devonshire and Cornwall
are the equivalents of the old red sandstone? ‘They have
indeed, to a great extent, assumed a new mineral type—we
say to a great extent; for we ourselves, in both our pre-
vious memoirs, have described many of the rocks in question
as much resembling the old red sandstone.

Various causes may have co-operated in producing the pecu-
liar mineral character of the Devonian and Cornish strata.
Among these, igneous action is the most apparent, and the
country it is well known bristles with rocks of igneous origin,
many of which are well described by Mr. De la Beche: and if
(as we believe) he is correct in supposing that many of these
rocks were formed contemporaneously with the strata among
which they appear, we are furnished with one of the conditions
under which the mineral character of a part of this region of
the old red system has been greatly modified. But, independ-
ently of any supposed igneous action, what is there among the
analogies of sedimentary deposits which should not lead us to
embrace the view, that formations of the same epoch may
have completely distinct mineral types? Has it not been over
and over again demonstrated that the limestones of any par-
ticular series are often represented by siliceous sandstones, even
at the opposite extremities of our island, though the order in
which the organic remains occur is precisely the same in these
different rocks? The sandy and shaly strata of the coast of

* See Geol. Trans., vol. ii. p. 125.

of the Older Stratified Rocks of Devonshire and Cornwall. 253

Yorkshire and the hard siliceous fossil grits of Brora, proved
to be of the same age as the Oxfordshire oolites, are among
the many striking illustrations of a phenomenon, of the pre-
valence of which, indeed, no stronger proof can be given, than
that geologically and zoologically considered, the massive Clays
of the London basin are the same as the white limestones and
hard siliceous grits of Paris.

In applying, therefore, these analogies to Devonshire we
should say, that if the true mountain limestone (under its
ordinary aspect) thins out and is no longer traceable, we ought
to look for its equivalent in sandstone and shale: and in ac-
counting for the great development of many marine animals
which appear in the Devonian limestones, we have, @ priori,
reason to expect the appearance of large stratified masses of
calcareous matter.

If these views be confirmed by our best fossil conchologists
(of which we have little doubt), then will they have a most
important bearing upon the classification of the ancient rocks
of foreign countries, and we believe also of Ireland. In large
tracts of Europe, the first great series under consideration, (to
which one of us applied the word “ system,”) is supposed to be
wanting: but if this supposed absence be founded chiefly on
mineral characters, the representative of the system may still
be discovered by its typical organic remains, though enveloped
in rocks like these of Devon and Cornwall, or in strata still
further removed from what we have been in the habit of re-
garding as the general type*.

Conclusion.— We had no intention a few weeks ago of wri-
ting upon this subject. It is true that we had been gradually
changing some of our views respecting the age of the oldest
rocks of Devon and Cornwall (since the suggestion of our
friend Mr. Lonsdale before ailuded to); and we should soon
have placed our opinion upon record before the Geological
Society. The publication, however, of the Report upon the
Geology of Devon and Cornwall, seen by one of the authors
for the first time within these few days, compels us, in justice
to our character, (for it is now not merely a scientific, but also

* We are led to believe, from the data already before us in the works of
foreign authors, that the old red system will be found in the provinces of
Rassia and the Scandinavian countries, as well as in Poland and Germany.
M. Elie de Beaumont has recently written to one of the authors, and ap-
proving of the establishment of the old red sandstone as a separate
“System”, he says that he has no doubt it will be largely found on the
continent.

+ At the conclusion of a note affixed to p. 130 of Mr. De la Beche’s Re-
port on the Geology of Cornwall and Devon occur the following words :
“ He,” the Rev. D. Williams, “ observes, that he stated the fact of the car-

254 Prof. Sedgwick and Mr. Murchison on the Classification

a moral question) to state immediately and concisely what our
views have been and what they now are; in order that our
scientific brethren (with whom our statement cannot fail to
produce its proper effect,) may have it in their power to draw
a just conclusion as to the part we have taken in the new clas-
sification of the rocks of Devonshire and Cornwall. If any
one should think that there is somewhat of a polemic spirit
either in this page or those which follow, we request him to
bear in mind, that the determination of the great culm trough
of Devon and the settlement of its true geological position, is
the key to the whole structure of the two counties; and that no
one was in possession of this key, until in 1836, we offered it
to the British Association at Bristol.

We pass over the circumstance alluded to in the note be-
low, trusting that Mr. Dela Beche is incapable of insinuating
that which he knows to be incorrect; and we shall conclude
this sketch with a short statement of facts in relation to his
operations and our own. We have already stated, that before
we entered upon an examination of Devonshire, Mr. De la
Beche had exhibited a map to the Geological Society which
he said was complete, and which was afterwards on sale for
some months. It contained many excellent details, the result
of the labours of former years, and on the whole was justly
considered to be of great value: but it made no separation of
the culm-bearing or carbonaceous strata {rom the older rocks.
Before our visit to Devon, this author had, in fact, neither

bonaceous recks occurring in a trough, bounded by the ridge of Exmoor on
the north, and the granite of Dartmoor and slates of Foerabury and Bos-
castle on the south, at the Meeting of the British Association held at Dub-
lin, in 1835. (Report of the Proceedings of the British Association, Oct.
7, 1837.) We are compelled to give an unequivocal contradictioa to
this statement. We were both present at Dublin when the paper alluded
to was read, and we took part in the short discussion by which it was fol-
lowed; and we assert that the author, the Rev. D. Williams, considered the
fossil plants he exhibited from Devonshire, as derived from the oldest grey-
wacke rocks of the district, and yet identical with those of the true coal-field
of Pembroke. He described no section, and made no allusion whatever to
the existence of any overlying carbonaceous trough. This assertion is per-
haps superfluous on our part, for we have only to appeal to all the geolo-
gists who were present at the Dublin Meeting, and to refer others who were
not there, to the abstract prepared by Professor Phillips from Mr. Williams's
short notice, for such it really was. An assertion of Mr, Williams, made in
the autumn of 1837, and which till this time we never saw, is put forth to
establish his pretension to a discovery said to have been announced to the
British Association in 1835; while neither the official records of the Asso-
ciation, nor, as far as we can learn, any journal of that year, make the
slightest allusion to such a circumstance! The facts speak for themselves.
Weare the first persons who pointed out the existence of the carbonaceous
trough; and we never received the smallest hint of the sort from Mr, D.
Williams.

tt

- of the Older Stratified Rocks of Devonshire and Cornwall. 255

separated the culm measures as a distinct formation, nor had
he ascertained their place in the general section; for he had
so far mistaken their relations, on their northern limits, as to
place them zo¢ over (as he now does after our example), but
under the first three groups of the older system; and their
southern limits he had never ascertained. In short, to work
out this point it was necessary he should do what he had not
done—to separate the black or culm limestones from the other
limestones of Devon; for without this it was impossible for
any one to take the first step. As soon as our new views were
announced, he suppressed the map as originally coloured,
and revisited Devonshire to make himself acquainted with the
fresh data, which he had now no difficulty in doing. Major
Harding had, indeed, pointed out to one of us the existence
of the culm limestone even as long ago as 1835, at the time
when Mr. De la Beche’s map was first exhibited. Great
therefcre was our surprise when we perceived that no distinc-
tions were drawn in the ordnance geological map between
this very remarkable flat-bedded limestone, and those lime-
stones of a slaty character which predominate in other parts
of Devon; the more so as the fossils of the one are entirely
distinct from those of the other. So palpable, however, is
the line of demarcation between the rocks containing the black
or culm limestone and those containing the slaty limestone,
that Major Harding, though then very slightly acquainted
with geological phenomena, had traced the boundaries of the
two classes of deposit from Barnstaple by Swimbridge and
Venn before we entered Devonshire, calling the one mountain
and the other transition limestone, and had thus prepared an
excellent point of departure for our examination. On the
south side of the trough (as we afterwards showed it to be),
Mr. De Ja Beche referred the inferior part of the culm series
to the oldest system of Devon and Cornwall; because it al-
ternated, like the Cornish killas, with certain contempora-
neous trap rocks. We pointed out to him the imperfection
of this reasoning, because similar alternations take place
among rocks of many ages, and therefore by themselves prove
nothing. Now, in 1839, Mr. De la Beche publishes his Re-
port, accompanied by an index map, in both of which he
adopts our view respecting the right mapping of the culm
measures as a distinct formation, which he calls “ carbona-
ceous rocks:” and although before our visit he had always
insisted on these rocks forming an integral part of the grey-
wacke series, he now gives valid reasons for their separation,
yet without acknowledgement, and with no other indication
that we were the agents who produced this change in his

256 Prof. Sedgwick and Mr. Murchison on the Classification

views, except the announcement, in a few words, of what oc-
curred at Bristol, from the perusal of which no one could
deduce any correct inference as to what we really had done.
A single sentence, a mere parenthesis (if ¢o the point) would
have satisfied us; and would not merely have been right, but
would have been prudent.

Whatever may be, even the small merit of our labours in
Devonshire, this at least we affirm, that they are perfectly
original. In passing from the north coast to the south, across
the whole county, we were astonished at the novelty and
unexpected nature of the phenomena that successively rose
before us, contrasted with every thing we had before under-
stood from those who had examined Devonshire. We were
amazed when, after having ascertained the separation of the
culm-measures from the underlying slaty rocks, we stood upon
the cliffs of Clovelly, and found ourselves compelled by the evi-
dence before us to sketch them in as the highly inclined masses
of a coal-field, dipping away from the more ancient strata of
North Devon: and still greater was our surprise when, following
those cliffs by Bude we found the same carbonaceous or culm-
iferous system still rolling over in countless striking flexures,
till passing into North Cornwall it rises up against and rests
upon the older slates of that county. Nor again were we less
surprised on finding the same system lifted up, penetrated,
and altered by the granite of Dartmoor. So far from any
attempt having been previously made to effect this great sepa-
ration, the position even of the several limestone bands in
North Devon had been mistaken by Mr. De la Beche, and
considered by him as the repetition of the same calcareous
group by successive undulations. ‘The truth is, that no one
can make a correct section among slaty rocks till he learns to
distinguish cleavage from stratification ; and it is astonishing
how very few geologists are even at this time masters of the
subject. This is we believe the explanation of some of Mr.
De la Beche’s early difficulties, and may be the reason why he
did not first separate the culmiferous deposits (as he now does)
from the greywacke of Devonshire.

Should any one ask what we effected in Devon, we reply,—

1. That we were the first to give anything resembling a
correct section of the mineral masses between the N. and 8.
coasts of Devon; and till such a step was taken, it was im-
possible to commence any classification of the subordinate
groups.

2. That we determined the relative place and succession
of the distinct calcareous and fossiliferous groups.

3. That we proved the existence of the culm limestones on

of the Older Stratified Rocks of Devonshire and Cornwall. 257

both sides of a great trough, and included the hitherto anoma-
lous limestones of Holcombe Rogus in the same carboni-
ferous system.

4, That we ascertained the subdivisions of the culm series,
and laid down, for the first time, on a map, its extent (with one
limited and perhaps doubtful exception at its south-eastern
extremity near Ashburton), thus converting the supposed an-
cient greywacke rocks of nearly one-half of the large county
of Devon into equivalents of the carboniferous system, as it is
already represented in two published geological maps*.

In attempting to classify the oldest rocks of Devon we fell
into some false conclusions from imperfect data. (These we
have corrected, and the whole series of Devonshire and Corn-
wall is now, we trust, exhibited in harmony; the lower sand-
stones and slates being the equivalents of the old red sand-
stone, the next natural group beneath the great coal-bearing
strata of the British Isles, and the whole being exhibited
under peculiar mineral types.

In asserting that the older stratified rocks of Devonshire
and Cornwall are upon a broad scale the equivalents of the
carboniferous and old red systems, we do not however deny
that in some tracts the lowest members of these rocks may
represent the upper division of the Silurian System: for al-
though we have as yet found few if any of the fossils most ty-
pical of that system,we admit that when the sediments of a given
epoch have been accumulated under peculiar conditions, we
must expect to find considerable variations in the forms of
animal life. Again, we know that the older rocks of this
region have undergone great changes in assuming their pre-
sent hard and slaty character; and under such circumstances
the difficulty of precisely limiting the boundary line of any
given portion of them is prodigiously increased. In tracing, for
example, the Silurian System from its typical region into
the sea-cliffs of Pembrokeshire (where its place in the series
is so precisely marked in Broad Sound) we perceive its ordi-

* See small map of England, in the corner of the large map of the Si-
lurian region. See also Phillips’s General Geological Map of the British
Isles. In the latter it has been inaccurately stated (in acknowledging the
sources from which the author drew) that Devonshire is coloured from Mr.
De la Beche. Professor Phillips has promised to correct this error in the
new edition of his map which is about to appear, as he is fully aware, to-
gether with every geologist who was present at the meeting of the British
Association, that we first proposed this great change: and even now,
though Mr. De la Beche has bllowed us In separating the carbonaceous
rocks from the greywacke, and represents them under a distinct colour,
he does not admit them to be the equivalents of the carboniferous
system of England.

Phil. Mag. §. 3. Vol. 14, No. 89. April 1839. s

258 Prof. Sedgwiek and Mr. Murchison on the Classiticatio n

nary lithological aspect almost entirely obliterated; the rocks
which occupy the place of the soft mudstones and argillaceous
limestones of Salop and Hereford, &c. have become hard,
siliceous sandstones, with a slaty cleavage; and affording no
evidences of clear subdivisions, they can be divided into
broad groups by the help alone of a very few of the same fos-
sils which teem in the greatarea of the Silurian region. As
Pembrokeshire, lying as it does between the Silurian region
and Devonshire, prepares us, by the peculiar structure of its
coal or culm-field, to recognize an almost perfect analogy of
structure in the culm-field of Devon; so do the great changes
which the underlying old red and Silurian systems have there
undergone, predispose us to believe that the strata which sup-
port the culm-field in Devon may present themselves also
under a peculiar mineral aspect. Notwithstanding, however,
this caution as to the possibility of some lower members of
the Devonian and Cornish strata representing Silurian rocks,
we adhere to the conviction, that the great mass of the strata
which support and appear to pass upwards into the culm-field
are the equivalents of the old red system properly so called.
Instead of thinking ourselves rash and hasty in making the
generalization above given, we would rather accuse ourselves
of being tardy and over-cautious ; and we are now surprised
(notwithstanding the imperfection of our evidence) that we so
long retained the older rocks of Devon and Cornwall in the
place where we classed them on our return from these coun-
ties in the autumn of 1836. For our conclusions, excepting
their generality, are not entirely new. Some of the red sand-
stone groups, at least, of South Devon, have often been called
old red sandstone; and they are so regarded by Mr. Austen ;
who also considers the Torbay limestone as the equivalent of
the mountain limestone. Mr. Greenough, many years since,
pointed out the extreme difficulty of separating the Plymouth
limestone from the mountain limestone ; and Mr. Lonsdale,
a considerable time since, believed that the system of South
Devon would at length be proved only a peculiar development
of the old red sandstone; and he freely stated this opinion
to Mr. De la Beche as well as to ourselves. The present
opinions of Mr. De la Beche are before the public, and we
have no right, perhaps, to be his interpreters. He puts forth
several hypotheses, without positively adopting one of them.
He must, however, (after the recent publication of such large
groups of Silurian fossils) before long perceive that the for-
mations of South Devon not merely contain fossils approach-
ing those of the mountain limestone (a fact long known), but
that their whole suite of fossils is intermediate between those

of the Older Stratified Rocks of Devonshire and Cornwall. 259

of the Silurian and Carboniferous Systems; a fact which at
once defines their true place in the sequence of British rocks.
The hypothesis he seems most inclined to adopt is the fol-
lowing:—That the calcareous and slaty system of South
Devon is the newest, being above the carbonaceous system;
and that the carbonaceous system is newer than the grey-
wacke north of Barnstaple. In this way the calciferous band,
* extending from Torbay, &c., into South Cornwall, would
be in a higher part of the greywacke series, and might be
even equivalent to the beds known as the old red sandstone.”
—(Report, &c. p. 149.)

We agree with the concluding remark; but not for the
reason hypothetically stated, viz.: that South Devonis in a
higher part of the greywacke series; for we place the North
and South Devon groups on the same parallel, and consider
the culm-measures as unequivocally superior to them both.

So long as we were unprovided with a typical suite of fossils
from the older system of Devon, it was impossible to propose
for it any name; but now, having discovered a great many of
its fossils, and that too in regions wherein the red arenaceous
character gives way to the slaty impress, and a very different
mineral aspect; the necessity of adopting a new name becomes
apparent, and we propose the term ‘ Devonian System” as
that of all the great intermediate deposits between the Silurian
and Carboniferous Systems. The “ Devonian System” is
so far unexceptionable, that it may be applied, without any
contradiction of terms, to rocks of every variety of mineral
structure which contain the characteristic series of organic
remains.

When these organic remains are described, we shall then
have a regular descending order of the older fossiliferous
strata in the three great lower systems which pass into each
other, the Carboniferous, Devonian, and Silurian. Whether
the still lower slaty rocks to which one of us applied the term
Cambrian, may or may not contain, in their inferior parts,
distinct typical fossils, is a problem not yet solved, though as
far as our labours have gone, we know that many of the shells
which characterize the lower Silurian group, exist also (even
at considerable depths) in the great upper Cambrian group,
and therefore the line we have provisionally drawn between
the Silurian and Cambrian Systems may, eventually, be fixed
by some natural grouping of fossils at a different level.

We proposed the use of the terms Silurian and Cambrian be-
causewe believed that their adoption, (L. & E. Phil. Mag., vol.
vil. pp. 46, 483,) when applied to well-defined mineral masses,
might tend to clear away the obscurity which we were per-

260 Mr. Halliwell on an account of the comet of 1472.

suaded would hang over the older rocks as long as they were
all considered to belong to the dark and undefined era of
‘* Grauwacke:” and we trust that we have, in this memoir,
shown strong additional grounds why this mineralogical term
should be disused by geologists, as a term of classification,
applied as it has been to rocks of such very different ages ;
thus serving as a shelter for ignorance, and paralyzing every
effort for deterinining the succession of strata upon true
principles. If its lovers wish still to cling to it, let them use
it as an adjective and tell us of Carboniferous, Devonian, Silu-
rian, and Cambrian “ Grauwacke,” and then, at least, the
term will do no mischief. The continuance of the use of this
term to represent different epochs in the history of the earth
would be as absurd as to retain the old “ flétz” formations
of Werner, after it has been shown that such rocks are often
as highly inclined as the most ancient strata; but we trust that
any wrangling about this barbarous word is nearly at an end;
for already some of the best foreign geologists have discarded
its application to the upper systems of transition rocks, and
now restrict its use as a term of classification to the lowest
slaty or Cambrian rocks.
March 25, 1839.

[A Postscript to this paper will be found at p. 317 of the present Num-
ber. ]

XLI. On a very particular and curious Account of the Comet
of 1472, from a contemporary MS. Chronicle in Peterhouse
Library. By J.O. Hatuiwe11, Lsg., F.S.A., of Jesus
College, Cambridge.

To the Editors of the Philosophical Magazine and Journal,
GENTLEMEN,
HE following minute description of the comet of 1472 is
taken from an autograph chronicle of English affairs by
John Warkworth, master of St. Peter’s College, Cambridge,
still preserved in the library of that institution. I am pre-
paring the whole for publication for the Camden Society.

«* And in same xi yere of the kynge, in the begynnynge of
Januarii, there apperyd the moste mervelous blasynge sterre
that hade bene seyn. It aroose in the Southe-Este at ij of the
cloke at mydnyght, and so contynued a xij nyghtes, and it
arose ester and ester till it aroose full este and rather. And
so when it roose playn Est, it rose at x of cloke in the nyght,
and kept his cours flamynge Westward overe Englond; and
it hade a white flaume of fyre fervently brennynge, and it
flamed endlonges fro the Est to the Weste, and noght vp-

Prof. Powell on the Dispersion of Light. 261

right; and a grete hole theirin, whereof the flawme cam oute
of. And after a vj or vjj dayes it aroose North-Est, and so
bakkere and bakkere, and so enduryd a xiijj nyghtes full
lytell chaungynge, goynge from the North-Este to the Weste
and sometyme it wuld seme a quenched oute, and sodanly it
brent fervently ageyn. And then it was at one tyme playne
northe, and then it compassed rounde aboute the lode sterre,
for in the evynynge the blase went ageyns the Southe. And
in the mornynge playne northe, and then afterward West,
and so more West flamyng vpryght, and so the sterre con.
tynued iiij wekys tylle the xx day of ffeveryere ; and when it
appered West in the fyrmament, then it lasted alle the nyght,
somewhat discendyng with a grettere smoke on the heyre;
and som men seyd that the blassynges of the seide sterre
was of a myle lengh; and a xjj dayes afore the vanyschynge
therof, it appereryd in the evenyng, and was down anon
within two oures, and evyr of a colour pale stedfast, and it
kept his course rysynge west in the northe, and so every
nyght it apperid lasse and lasse tyll it was as lytell as a hesyll
styke, and so at the laste it vanesched away the xx day of
ffebruarii. And some men saide that this sterre was seen ii
or iij oures afore the sunne rysynge in Decembre iijj days
before Chrystynmasse in the Southwest, so by that reasoune
it compassed rounde abowte alle the erthe alleway chaungyng
his cours as is afore rehersid.”

The observationsof Johannes Regiomontanus upon the same
comet are recorded in the Nuremberg Chronicle. Wark-
worth’s description was lately commuicated to the Society of
Antiquaries by my friend Mr. Bruce, and my object in send-
ing it to you was to afford an opportunity for those of your
readers to peruse it who are not likely to meet with it through
any other source. Your obedient servant,

J. O. HaLiiwe 1,

XLII. Observations on some points in the Theory of the
Dispersion of Light. By the Rev. Baven Powert1, M.A.,
LRS., F.G.S., F.R.AS., Savillian Professor of Geometry,
Oxford.*

HE problem of the dispersion was, for a long time, con-
fessedly the opprobrium of all theories of light, but
more especially, in proportion to its higher pretensions,—of
the undulatory, not simply because it had not explained those
phenomena, but because, according to the received views, it
was at variance with them. It has only been within the last
few years, that, by a modification of the principles of this

* Communicated by the Author,

262 Prof. Powell’s Observations on some Poznts

theory, it has been brought to bear on the question of the
dispersion. Yet there are still those who are so unreasonable
as to inveigh against the theory,because it has not, in that com-
paratively short period, succeeded in clearing the subject of all
its difficulties ; and who, instead of any degree of satisfaction at
what has been done, express only displeasure at what has not
been effected. Passages might be cited (were it to any pur-
pose to do so) from the writings of some philosophers of the
present day, in which complaints of this nature occur, in-
volving remarks and reflections which we cannot well set
down to ignorance, and which, in any other point of view,
can neither be regarded as peculiarly creditable to the taste
of the writers, nor to their appreciation of what is justly due
to a series of researches of such a character as must fairly be
allowed to beiong to those in question, even if they could be
shown to have failed in their object.

It is not however my design in the present observations to
enter into controversy, but merely to offer a few remarks on
one or two points connected with that part of the theory
which at present seems most open to difficulty and objection ;
and to which the attention of those who are in a condition to
grapple with the difficulties of this intricate portion of dy-
namical research, is at present most powerfully called.

In my first deductions from the theory of M. Cauchy, and
my earliest calculations to compare it with observation, I
made use of a formula which was allowed all along to be but
an imperfect and approximate one, and which was applied
numerically only by the aid of an indirect and tentative pro-
cess. A direct mode of calculation by it, was indeed stated and
explained (under a certain material limitation) (see London
and Edinburgh Journal of Science, April 1836, vol. viii. p. 309),
but this was in practice not less troublesome than the former.

The other and more exact methods proposed by Sir W. R.
Hamilton and Mr. Kelland, by which my later computations
were carried on, involve a greater number of constant coeffi-
cients; which by consequence, directly or indirectly, must
be assumed from observation. ‘The nature of these assump-
tions, and the precise difference between the two formulas,
I pointed out in a paper in the Lond. and Edinb. Journal of
Science, January 1836, (p. 26,) and March 1836, (p. 206).
It will be desirable here briefly to restate them:

The exact formula deduced immediately from M. Cauchy’s

theory is, f AEY 32 a
m1 er x H as : (1.)
c ( A ) “i

This, it may be well to observe, is equivalent to the sum

in the Theory of the Dispersion of Light. 263

of a number of like terms, for the same value of pw and a,
such as, cr

| ef . a )
Feel
Xr

yes
+ HL? es ’) (2)
r

ste 2o 1)
Bh eee
Aa
a5 Hi, ( te Ax, y)
A

The summation being extended to all the values of Ax
which it may be necessary to include.

My first and approximate attempt at calculation was ef-
fected by taking a single term of such a series, with some con-
stant coefficient, which might be a sort of mean among all the
similar terms, and which (on extracting the root) would be,

wey aD

i sin(** )
teas

The peculiar function involved is easily expanded into a

series; and in this way the exact formula (1.) may be ex-

pressed by,

1 2 4
= P-Q-,4L4, — &. (4.)

os

Supposing 3 terms sufficient, this is the formula of Mr.
Kelland: in which the coefficients can only be found by as-
suming 3 indices from observation. An objection has also been
urged by Professor Lloyd, that, on pursuing the investigation,
from the relations which subsist between these constants, values
of them are given by calculation which are at variance with
those derived from observation. Ihave also remarked in re-
ferring to this point at the end of my paper (Phil. Trans-
1838, part i.) that to propose as a sufficient theory one which
requires so large an assumption of data from observation, ap-
pears hardly consistent with the just demands of what ought
te constitute a legitimate mathematical explanation of the law
of experimental results.

264: Prof. Powell’s Observations on some Points

Now to all who have attentively considered the nature of
those remarkable optical properties of bodies which are called
their refractive and dispersive powers, it will be evident that
we have a very peculiar case to consider. The problem we
have to solve is rather a combination of two distinct problems.
The dispersive and refractive powers follow no proportion
to each other, and it is almost impossible to conceive any
theory, or even any empirical mathematical law, which could
connect the two together. For example, we have diamond
and water, with refractions nearly double the one of the other,
and dispersions nearly the same. Flint glass and oil of cassia
with the same refractions nearly, and dispersions as about
1 to 3. In a word, the absolute magnitude of the deviation
of any given ray, or of white light, bears no relation whatever
to the difference of deviation between the extreme rays of
the spectrum, in different media. If then we seek a theory
to explain the facts, it would be not only unreasonable to ex-
pect it to connect such obviously incongruous phenomena,
but it ought most rationally to involve #wo distinct constants,
one belonging to the refractive PowER, the other to the re-

Jractive CHARACTER of the medium. And in conformity

with the general conditions of formulas of this kind, we might
expect that, directly or indirectly, we should have to assume
two quantities as given by observation, in any calculation to
compare theory with observation, for the spectrum of a par-
ticular medium.

Now if we take the formula (1.) above stated, it is at once
manifest that if Aw be very small compared with A, we have
for all values of A very nearly,

ee TENG
sin een,
ae eee oh: 5.
Lavan ?) (5-)
A
or there is no dispersion, and the formula is reduced to
1
= 2 ° H? 6.
2 (6)

Now, in any medium, if Av be not very small compared
with 2, we shall have different refractive indices for each
ray, which will differ less as A becomes greater; and if we
suppose A to increase indefinitely, (A x remaining finite) the
above expression (6.) will be the dimz¢ to which the refractive
index constantly tends, and from which it does not sensibly
differ when A is supposed large; that is, for some ray beyond
the red end of the spectrum (and such may exist though not
sensible to the eye) there is an absolute limit to all refraction,

in the Theory of the Dispersion of Light. 265

different in different media; this may be called the refraction
constant. If we had any means of determining it by experi-
ment, it would be a most important step for the theory. But
it is evidently a datum quite independent of the dispersion.
This quantity corresponds to (/) in Mr. Tovey’s notation,
and to (P) in Mr. Kelland’s, who has determined it for
Fraunhofer’s media; as I have done for several of those I
have examined. (Phil. Trans. 1838, part i.) It is an index
not greatly below that for the red extremity of the visible
spectrum. Whether it may possibly be connected with the
refraction of eat may become an interesting question.

To return to the dispersion :—according to the exact me-
thod we have still two more constants to determine, viz. in
Mr. Kelland’s notation (Q) and (L); in Mr. Tovey’s (/') and
(A!) : these like the former must be ultimately derived from
observation, and they are in fact obtained from the assump-
tion of two more observed indices.

But pursuing the same idea as that just adverted to, it
would seem reasonable that as one datum for each medium is
the refraction constant, so one more should supply a disper-
sion constant; and, on looking at the nature of the formula,
it would seem that this should depend on the arc 7 Aa.
Now the coefficients Q and L arise from the summation of
the various combinations of H, and Az,; H, and Az,; H,,
and A’x,,,&c. And if we recur to the simple consideration
of one term of the summation, which furnished my first ap-
proximate formula, we shall see that we here avoid this diffi-
culty, and in fact have only the /wo constants of refraction and
dispersion to derive from observation. And though it may
be true in reference to the physical theory that for the adop-
tion of that formula no legitimate ground appears, yet for the
reasons already adduced it may be worth while to examine
the application of it more closely.

If we take the simple formula (3.), or what is the same
thing, on developing, (see Lond. and Edinb. Journal of Sci-
ence, Jan. 1836) and substituting the value of 4 in alr,

°

Ls hing bel Anyt : K (wA.2)* ke. (7.)

p 120 at
writing for abridgement, Av = 4,
it pe 1 pe
P= 6 2? and g= 120 nF?
we shall have, for any one ray,
1

Ht eee + gh (8.)

266 Prof. Powell’s Observations on some Points

and for any other ray of the spectrum,

1
=P + 96 (9.)
Then eliminating H, we have
0 = (u—p,) — (p—P,) ® + (g—4,) (10.)
and
—(u—,) 4 PP
—_1———t = #-— (5 6? i Ni hes
(q-4) ae foe
or for abridgement
—m = #* — ré? (12.)
whence by solving the quadratic we obtain
Repairs (aya ists
OF ee : <2 M+ = (13.)
in which
pe i
aD a ( ade a )
Sir meen die cs Mik (14)
( at i Be.)
als (W—/,)
1 Me) (15.)
T9048 ~ AF

If then we take the ¢wo values » and p, from observation,
we readily find 6, and thence again obtain the value of H, by
substituting in either of the expressions (8.) (9.). Then, in
the same expression for every other ray of the spectrum, sub-
stituting §, we shall find H; which, if the formula be correct,
ought to result the same for every ray.

This process then, if it be considered allowable, affords
this material advantage, that it requires only the assumption
of zwo values as given by observation for each medium, which
we have just seen is exactly the improvement required in
theory. Now though I have not as yet tried the result of
calculation precisely in the way above stated, yet it is evi-
dent that all the calculations I made in my two first papers
in the Phil. Trans., including all the results of Fraunhofer
and, Rudberg, were conducted on an hypothesis which is in
principle identically the same: and in all those it is univer-
sally allowed the coincidences are as close as could be de-
sired: so that it is evident that this supposition cannot be
very far from the truth ; calculation grounded upon it has not
yet been applied to more highly dispersive media. But it
becomes extremely important to see whether it may be so ap-
plicable ; whether it may apply even as well as the methods
proposed on the less restricted hypotheses, such as I have em-

in the Theory of the Dispersion of Light. 267

ployed in my later calculations; but which essentially involve
the fault of requiring too large assumptions from observa-
tions, and these too, according to the remarks of Prof. Lloyd,
leading to conclusions inconsistent with truth: this he has
pointed out in a letter to myself; the details of his investiga-
tion have not yet been published; but there is a short abs-
tract of them in the Proceedings of the Royal Irish Academy,
No. 1. p. 10, and some mention of the subject was, I believe,
made at the British Association 1838, in the Physical Section.
I have reason to hope that the paper will before long be
published, meanwhile it may not be irrelevant to offer one
observation more on the subject.

Since such a formula as the above is unquestionably very
nearly accordant with the truth, through, at least, a consider-
able range of media, it certainly becomes important to ex-
amine, whether any theoretical conditions are conceivable,
which may warrant the adoption of it, as at least a good ap-
proximation ; and the question obviously reduces itself to
this: whether in taking the sum of an indefinite number of
terms which are combinations of H, and Axz,, H, and A x,,
H_,, and A x,,,, &c. (the form of which is seen in my paper,
Phil. Trans. 1838, part ii.), we may not discover some ground
for justifying the adoption of a single term containing some
mean value of Ax combined with a constant coefficient H,
such, that we shall have accurately or nearly,

sin? (2%) 1]

How far the dynamical conditions of a system of molecules
such as that supposed by M. Cauchy and the other eminent
mathematicians who have treated on the subject, may be found
susceptible of rae to any such deductions (in which the
process would be perhaps somewhat analogous to finding the
expression for the centre of gravity of a system of particles,)

268 Mr. Maclean’s Meteorological Register

I would leave to the meditations of those more familiar with
the analysis of dynamics. But I trust some of those readers
of this Journal, who are so able to discuss such a topic will
not think it unworthy of their attention.

XLUI. Meteorological Observations made during Voyages in
the Atlantic and South Pacific Oceans ; and Altitudes in the
Vicinity of Lima measured by the Sympiesometer. By Joun
Mactean*,

Meterevlogical Register from the Cape de Verd Islands to Callao,

Thermometer in the Cabin, and a fair exposure.

Date. Asati en Latitude. | Wind and Weather. Observations.
|
1821. ;
Sept.22. 85 calm and clear.| off Cape Arit.
23. 82 light air. Cape de Verd.
30. 83
Oct 1: / Souey ede n. lat.
2.\76| 78) 4 59 wsw., rainy. long. 17° 30’
St 82} 4 44 s., clear.
4. 82535 4 4 s., clear.
5. 82| 3 34 southerly.
6. ieee. 3
7. 81| 2 46 a
a iy cl et) 2 ssw.
Te 7S PSH ad lke bp 7 ssw., breezes.
10.1 °78:| 79 | 1 37 ssW. long. 14°
12.178} 80] 1 0 s. by E.
13.| 78 | 79| 0 20 s. lat.
14.| 78 | 80| 1 25 | s. by w., light.
15.|77| 79 | 2 42 |sx.byz., breezes.
16.| 77 | 79| 418 cloudy.
17.|77| 80] 6 32 3
18.| 76| 79] 8 48 ¥
19.| 76} 79 | 10 47 SE. by E
20.176 | 79 | 12 43 by
21.| 76! 79| 14 55 -
22.| 76 | 79 | 16 48 NE. many birds.
23.| 77 | 80| 18 38 w. by E.
24.| 77 | 801 20 40 | variable, rainy.
25.| 74 | 74] 21 13 Ss.
26.| 74 | 73 | 22 21 EsE., cloudy.

* Communicated by Professor Sir W. J. Hooker, LL.D., F.R.S. The
author observes, with tespect to his Meteorological Observations: “ My
chief object in sending these is to show the trifling change in the thermo-
meter during winter and summer in the extreme southern latitude, where
it appears the cold is only severe when the wind is from the southward,”

7 At 4 p.m. 79°. 1 At 6 am. 80°; 8 p.m. 82°. § At 6 a.m. 79°.

from the Cape de Verd Islands to Callao. 269

Tae continued.

Date. | Thermometer.
'8 a.m.} Noon.

— | = ——_—_—

Lati- | Wind and Weather.

tude. Observations.

——

1821.
Oct. 23° 29! rainy. 5
clear. =
=
at Rio Jan. S
Nov. i
25 29| Nnx., clear. a
26 5 | Nes cloudy. =
27 46) light winds. =
29 20 SE. S
31 18| xEse., cloudy. | Many birds. =
33 24| NeE., clear. 3
35 32) light clouds.
36 27 cloudy. Many seals and penguins.
Dec. 36 34 s., clear. md
37 32| nw., cloudy. Oia kanes
39 3) sE., blew fresh. AS ae a
39 46| _ sE., clear. 5 Siste
4] 46) N., cloudy. a Gest S
43 17 \southerly, clear. ee S
45 25 \w. byssw., blow- = §s & 2 2 3
46 53 [ing. FO yee
48 14| w. bys. clear. Baw
49 46 |nw. & w., cloudy. 5 gis
51 41 \w. & wsw., clear. | Long. 59° 4! ea.
52 31| N.Nw. & sw. ass
ralny, clear. 2 es
om
53 1 |sw. gales, & hail- aay :
storms, but ge- = ge
nerally clear. cs)
s. by w., gales, 3
with snow and
hail, cloudy.
53 2| w., changeable,
and towards
evening calm.| Long. 58°.

ssz.,calm,cloudy-
53 42) 5,

”

54 36| blowing, and | Immense numbers of
changeable, ducks from Staten
and hail. Land.

54 57 | se. to wsw., clear
and cloudy.

56 25) wsw., to wnw.,

57 22\ nw., do.
57 33] hazy with rain,
then clear.

270 Met. Reg. from the Cape de Verd Islands to Callao.

Date.

Dec. 24.

1822

1821.

25.
26.

Jan. i

Se SS EC tS ea

45 | 45

43
42

46
44
4]

42
46

44

46
46
47
46
44
49
50
49
50
49
50
dl

51
52

TaBLeE continued.

Thermometer.) Lati- | wind and Weather.
8 a.m. Noon.

—_——)|—--——___—.

tude.
57 43] Nw.to wsw.,
blowing hard Se
gales. 2°
58 17 \wsw.to w., gales|Read a book at ©-3
and clear. midnight by $5
58 45 |sw. byw.,cloudy| daylight. Ss
andclear. Long. 71 . on
Bu
58 23 |w. bys. to sw. by 2 : 3
w., foggy & rain. 2 oO
WNw. to wsw., SEL
foggy then clear. ape
59 54| wsw.tosw., Peas
changeable oe
weather in the xe
morning. 2
nw. byn. to z., |Lat. 60° 3. Be
thick rainy. aS
w.byn.to w. by s. oS
hard gales with 22
hail. =e
57 56] sw. townw.,
clear then cloudy./Sometime past north-east-
Long. 75° 31. | erly currents; many sea
57 48| wnw.tow., | birds, few pardelas, some
cloudy. penguins, and until to-
58 36| Nw. by nN. to n,| day no albatroses,
Long. 77° 30!.
58 31| wnw.,clear. |Grampuses partly white,
Long. 79° 50!.| and porpoises black and
58 50} wnw., hazy. white.
Long. 82° 31'.

58 23] sw., clear, then
cloudy. Lon.83°.
sw., thick, with
rain.
55 4 |nw., hazy & rain.
Long. 83° 13’.
55 5) Nw.; clear, hail,
and rain in the
night.
54 46 |Ne., clear&calm.
54 4\sw., hazy & calm.
52 52| sw. tonw.
cloudy and clear.
Nw. to sw.,
cloudy and rain.
49 59| sw., cloudy.
47 6/\sz., clear & clou.

52 10

Observations.

Many Molly Manks and
other birds, apparently
of passage, smaller than
pigeons: much _ sea-
weed: no pardelas for
several days: few sea
birds ; occasionally an
albatros.

A flock of small appa-
rently land birds.

A large whale.

Variety of birds and two

divers.
Grampuses; albatroses,
always a few.

Meteorological Register round Cape Horn. 271

TABLE continued.

Date.

1822.
Jan. 16.

17.

“i
PO ONS Orb C9

Thermo.| Lati- Wind and Weather. Observations.

meter. tude.

ee

54 |45 19|w. by n., cloudy and
clear. Long. 83° 42’,
Long. 82°.

64 |41 33) nw. tosw., cloudy

and clear.

63 |40 32| sr. Long. 79° 30'. | Few or no birds these
64 |38 40| EsE., cloudy. four days.
64 |36 43\sE., cloudy and very| In apparent soundings

clear. for several hours:
64 Long. 75° 30'} Query, Ulloas shoals ?
65 Arrived at Valp.
65 wsw., cloudy.

65 |32 30) calm and cloudy.

66 |31 32) sw. tos.,cloudy. | Many whales.

68 |29 46 sW., 35

68 |28 17 S., 3

70 |24 48| ssr., cloudy & clear.

71 |25 38] sse., cloudy.

72 |24 4) cloudy and clear.

72 |22 15|ssE. to z., cloudy.

74 |20 2\g. by nz., cloudy and
clear, some rain
early in the morn-

ing.
76 |\17 42|k£. by nz., clear and
cloudy.
77 |15 27| ®. to sse., clear and | Several sperm whales.
cloudy.

71 | 13 50|sse. tos. by w., clear.) Many and various birds,
weed and seals.
75 |1215| -ssx., cloudy. Whales and many birds.

Meteorological Register round Cape Horn beyond the Equator.

Thermometer on Deck.

iden haleg Latitude. Wind and Weather. Observations.
8am, | South.

——_— ——_

ee

55° | 37 46 w., breezes.
54 | 40 46 5 ”

ts calm. Caught many pin-
49 |44 4] © sw., light winds. tados.

50 |no obs.| _ sz., stiff breeze.

4 Bs ditto.

45 i NE., fine breeze.

eee

272 Meteorological Register round Cape Horn.

TABLE continued.

a a ee

Thermo. ; 7
Tate: meter. it Wind and Weather. Observations,
a.m.

1833.
May 15.| 45 /no.obs.| NE., fine breeze.
16.| 43 |54 14] nw., fine breeze and

weather,
17.| 44 » _ cloudy.
18:43 N., thick and squally. A
19.} 43 |56 37] nw., stiff breeze. 3
Long. 70° W. =
20.|} 42 nw., hard gale. os
21,| 41 |57 28| Nw., snow in the a
morning. Ea
22,| 41 clear weather. | Passed Diego Ra- &
23.| 39 |56 3) wnyw,, fresh breeze mirez. 8
and clear. 3a
24.| 42 |55 37 |Nw., gales of wind and Sa
clear. ae
25.| 40 nw., sleet or fine Se
snow. > oO
26.| 40 |53 52] nw., hard gales and ete
clear. 5a
27. || er jo 48 w., clear.
28.| 37 | 49 50|sw.,clearthencloudy. =
A SS es 73) s., snow during this 2
day. a
30.| 37 |45 15) se., clear and cold. =
31.| 40 |42 35) s. clear and pleasant. a)
June 1.| 48 |40 5 sw., ditto. <
DA PST wa Nw., ditto. A whale.
3 54 |37 48 nearly calm.
4.; 59 |385 40 SE., gales.
5.| 59 |32 54} sxE., breeze, cloudy.
6 60 EN., gales, dark rainy
weather.
a 72 |28 15] NE., gales, ditto. Birds left us.
8 70 |27 37) Nw., night tremen-| A few birds returned.

dous squall with
lightning, morning

cloudy, and day fine.

9.; 75 |25 41) nw., cloudy, then

clear.
10.; -73 |25 5] w.s., clear and

changeable.

Bly ose ed Bess 7 NNW. tO NNE. No birds now with us.
12.| 72 _|238 50 variable.
13.| 75 |22 18|r., breeze, the trade

wind.
14.| 77 |19 42 E. Passed the Island of
15.| 78 |16 23 E., fine breeze. Trinidad.
16.{ 80 |13 16 E. Flying fish, falling

stars.

Meteorological Reyister from the Canaries to Callao. 273

TaBLe continued.

Date. ‘meter Latitude. Wind and Weather. Observations.

8a,

ee

June17.| 80 |10 13] &., fine breeze.
18.} 81 7 6) x. bys. 35
19.| 81 3 51 ss bi
20.; 82 | 1 2 S.ESE. 5, Many Physalia pelagica,
21.| 81 1 30) N. ssz., cloudy. ae ee
22. | - 82 2 53] s., light wind and

clear.

23.| 82 sic Mall ees bs 3

24.| 80 b Aim & wrauts,

25.| 80 w. and nw. ,,
26.| 80 | 7 56 NE) 9 A shoal of porpesses,
Noon | 89 emitted an unpleasant
smell.
27.| 80 calm and heavy rain.

28.| 80 9 7| wNkz,, fine breeze.

29.; 81 |10 9|Nne., clear weather.

30.; 81 |12 10} ne., fresh breeze,

cloudy.

78 14 22 ” ” ”

79 {16 24) ,, » Long, 37°.

78 18 57 ” ” ”

76 |21 34\ne. by £.

79 | 24 27| enx., clear weather.

27 9 ”

TOM 2BV25)\ Wes 5 *. light wind.

M2 N29 V7) gee wee 3

80. | 30 141) syobess

80 | 30 56] wne., nearly calm;
much gulf wind;
snow some days.

July

FP ONAGie oo
~I
©

_—

Meteorological Register from the Canary Islands to the Port
of Callao. Thermometer chiefly if not always on Deck.

Thermo.
Date. meter | Latitude. Wind and Weather.
8 a.m,
1834.
April 25.| 67 | 29° 43'| wnw., clear.
26.| 69 | 28 40} ,, light and clear.
27.| 70 | 27 16|N., breeze. ,,
28.) 70 23: 5 | NE. yy i:
99.| 72 | 22)444.,, ay hs
0.) 72 19 58 3 * -
May UF 71 Vif 24 ” ” ”
Z| 73 15 20 es ri rs
Ry i a ee Oa 4 » partial clouds,

Phil. Mag. S. 3. Vol. 14. No. 89. April 1839,

274 Meteorological Register from the Canaries to Callao.

TABLE continued.

Thermo-
mee at | Latitude. Wind and Weather,
a.m.

May 4.| 73 10 46 | nz, clear at sunrise ; thermometer at
713°, noon 77°.
Bl 7D 8 53 | ne., but light: thermometer sunrise 73°, in
sun at noon 102°, in shade 77°, sunset 77°.
6.| 79 7fe- A »» Clear.
Tole Si 5 33 | ,, afternoon variable and rain: thermo.
8

in the rain 75°, surface of the sea 82°,
ig ZB 4 46 | variable with rain.
9.| 80 4 9) nw., squally and heavy rain.

10.; 83 dead calm.

Il.) 84 3 30] sr., light. Long. 23° 35/.

12.| 82 calm, or light variable winds.

19.| 83 141} Therm. at noon 85°
N.

20.) 83 19 | se., fine breeze and clear. Long, 26° 40’.
s.

21.) 82 1°30). ”,) », thermometer noon 87°.

22.| 83 Sih | Ey Ng do. 85°.
23.| 81 Selous. morning squally, rain. Long. 27° 35’.
24.| 82 Vaca tua fresh breeze and clear: therm. in
shade at noon 85°, do. sun 106°.
25.) 81 9°50") 3, morning cloudy with light showers ;
shade at noon 83°, sun 104°.
26.| 81 1 br Aa ees fine breeze and clear; extremely hot
some time past, today somewhat
cooler.

27.| 80 | 14 41] ,, fine trade wind.

28.| 79 | 17 61. sz., trade still.

29.| 78 | 18 47 | light, cloudy, then calm.

30.| 78 | 20 20] light, and varied from nw. to sw. with rain.

31.| 76 sk., cloudy and rain.
June 1.| 76 | 2214] ,, _ light winds.

Di yh 7 Ginn W222 58 |nery, > > and clear.

Balt Je wiser Sunline as squally last night and this
morning, then clear : therm. air 7 a.m.
72°, do. water 78°; afterwards de-
scended to 67°, from evaporation of
course.

4.| 71 24 28 ,, cloudy.

5.| 73 | 25 38| ,, light wind, then calm.

6.| 73 NE. to wnw. and light.
7.
8

73 | 27 52) wne., fine breeze.
72 | 30 37 | nww. then w., fresh breeze ; thermometer at
sunset 67°.
9.| 62 | 32 37] w., blowing a gale.
10.| 59 | 3310] wsw., ditto.
11.|} 58 s., light, thermometer in sea 64°.
12.} 60 | 35 5] nw,, light.
13.) -61 36 47 | wsw., fine breeze and clear.
wnw., fine breeze, heavy dew in the night,
though cloudy.

Meteorological Register from the Canaries to Callao. 278

TABLE continued.

Thermo- 4
Date. meter at Latitude. Wind and Weather.
8 a.m.

(Ss ee eS ean i A ee

June 15.| 57 | 39 34 | se., light and drizzling thick weathef.
16.| 53 | 40 30! ,, blowing fresh and dark, then sw.
17.; 54 | 4010)sw., ,, hard. Long. 52° 50/.
18.| 50 | 40 0| ,, wind more moderate, small rain;
thermometer in rain 46°,
19.| 45 | 40 36! ,, blowing hard: thermometer noon 48°.
20.; 44 | 41 13 nearly calm, and thick afternoon, clear ;
thermometer in sun at noon 60°, shade
53°, water 49°, after evaporation 47°.
21.| 48 | 43 30 &., fine breeze; total eclipse of moon from
] until 7 a.m., very clear atmosphere.
22.| 47 | 46 6 | nw., blowing fresh; thick morning, cleared
towards noon.
23.| 44 | 48 48 | nnw., a gale, thick weather.
24.| 47 | 50 55 | nw., more moderate, thick; thermometer
at sunset 45°,
25.| 44 | 53 15 | wsw.to Nn. bye., light rain, afterwards clear.
26.; 44 | 54 10 | light wind; descried Staten Land; thermo-
meter in sun at noon 55°, shade at noon
45°, at sunset 43°, 8 p.m. wind of the
snow covered land 40°, in water 44°:
many luminous Infusoria caught here, as
well as in other parts near the line.
27.| 44 | 55 2) nw., light; thermometer noon 46°.
28.| 42 | 56 2| Ne. ,, hazy weather.
29.| 44 NW. | PR? oh and light rain: made
the island of Diego Ramirez.
30.| 40 | 57 22 | xw., blowing hard, thick weather; thermo-
meter at noon 41°,
July 1.| 38 | 58 4} w.innight, morning sw. clear.
37 | 56 38 | ssw., fine breeze, and clear; thermometer
at noon in sun 38°, in water 42°,
3.| 36 | 55 14| calm, then a breeze from ssz. with hail,
sleet, and snow; thermometer at
noon in sun 40°,
4.| 40 | 52 28 | ssr., fresh breeze, hail and snow.
5.| 41 49 45 | sw., fresh breeze; therm. shade at noon 42°.
6.| 46 | 47 32|nw., , ,, and thick; therm. shade at
noon 48°,
Te AG ea Ao 46n ti moderate Re i ‘ 47°,
8,.| 50 | 45 47] ,, PA » evening nF.
9| S51 | 45 2| w~. by w., to n. bye. and squally at noon.
10.;| 48 | 44 201 w., blew hard; thermometer at noon 48°.
11.| 50 | 43 2 | night fell calm, then w. by x. wind.
12
13
14

53 | 42 24 | ww., thick weather.
3.| 50 | 41 2) ,, variable, squally.
-| 51 | 38 28 | sw. and w., pretty clear weather.
15.; 55 | 36 28 | nw., fresh and thick.
16.| 54 | 34 11 | sw. morning, then calm clear weather.
17 A 56 6)'S3/ 18) 53, clear weather; thermometer
at noon 66° in the sun.

276 Mr. Ivory’s Bakertan Lecture :

TasLe continued,

SS SS — — —— ee

Thermo-
Date. pis Latitude. Wind and Weather.
a.m.

bes ———$—<$—

July 18.| 58 | 31 40 | sw., light and clear, heavy dew in night.
19.| 58 | 2930] ,, heavy dew and thick fog in morning.
20.| 61 | 2717| ,, light wind.

Ti beget 3 25 17 | s., breeze, morning cloudy, noon cleared.
22.| 61 | 22 45 | xsx., fresh and cloudy.

23.| 61 | 19 26] sx., fresh and cloudy; therm. sunrise 59°.
24,) 61 16 19 | xsx., fresh and cloudy.

25. got near Callao.

Heights of Places in the Neighbourhood of Lima, observed by
the Sympiesometer.

Hour of /Temper- ae Hygrometer.| Leagues
Date. Names of Places. Observa-| ature. | English |Boiling point) distance.
tion. feet. of water.
1837.
Dec. 22. |Lima to say......... 500
FC AvelLUIO ys aeons seer 10am.) 81° | 1,166) 15°208'| 6 | 6
., |Hillat Rio Seco ...| 2p.mj| 78 | 4,704 Sey te)
23. |Santa Rorade Quiveo| 5a.m.| 59 | 3,700| 20 2043) 5 |14
yi MBS Oven awe oatebe halieme(astoa 1Oe soaliaw 5,143| 22 202 | 4 |18
24. | Obragillo.......... Bsa | xD ntay 47 | 8,944| 9 5 |23
», |5an Buenaventura ..| 9 ,, 59 | 8,969| 13 QE 255
,», |Cross above S. Jose...| noon.| 60 | 9,998 23/28
25. | Huamautanga......... 8a.m.| 49 111,270] 17 192 | 23/303
26.|Pumchucu ............ 5 ,, | 514] 8,630] 18 195 | 25
»» | Cruz Verde.........-.. 96,3 69 | 4,655 Sule
cal MES PHO shes nein ws nee noon.| 83 | 2,248] 28 4| 93
», |Pumchanca...........- 4p.m.| 75 853| 21 209 | 4 {133
OPE NMAMA,, tatdcadsonbewses= ss 500| 14 210 | 5 |183

N.B. The hygrometer denctes the degree of cold necessary to produce
the dew-point.

XLIV. The Bakerian Lecture.—On the Theory of the Astro-
nomical Refractions. By James Ivory, K.H., M.A.,
F.RS. L. & E., Instit. Reg. Sc. Paris, Corresp. et Reg. Sc.
Gottin. Corresp.*

"THE apparent displacement of the stars caused by the in-

flection of light in its passage through the atmosphere,
is treated by the astronomer like most other irregularities
which he has occasion to consider. A set of mean quantities

* From the Philosophical Transactions for 1838, Part ii.

on the Theory of the Astronomical Refractions. Zit

is first provided; and the occasional deviations of the true
places from the mean are ascertained and corrected according
to the state of the air, as indicated by the meteorological in-
struments. The subject of the astronomical refractions is
thus resolved into two parts very distinct from one another;
the first embracing the mean refractions, which are an un-
changeable set of numbers, at least at every particular obser-
vatory; the second relating to the temporary variations occa-
sioned by the fluctuations which are incessantiy taking place
in the condition of the atmosphere. It is the first of these
two questions chiefly, or that regarding the mean refractions,
of which it is proposed to treat in this paper.

In order to form a just notion of the mean refractions, we
may suppose that some particular star is selected, and assidu-
ously observed for a course of time so considerable as to
comprehend every possible change in the condition of the
atmosphere; all these observed places being severally reduced
to some assumed state of the thermometer and barometer, and
being combined so as to eliminate occasional irregularities,
will determine the mean refraction of the star. In this pro-
cedure it is supposed, what experience confirms, that the re-
sult will ultimately be the same for the same altitude above
the horizon, provided the observations are numerous enough,
and extend over a sufficient length of time. We may in-
stance the star « Lyra observed by Dr. Brinkley; his obser-
vations are forty-four in number, extending over five years ;
and the greatest deviation of single observations from the
mean quantity may be stated at + 20". The supplementary
table, extending from 85° to 89° of zenith distance, publish-
ed in Bessel’s Tabula Regiomontane, is one of mean refrac-
tions calculated from many observations at every altitude.
The table, in the same work, extending to 85° of distance
from the zenith, which the supplementary one is intended
to complete, may likewise be considered as having the author-
ity of actual observation ; for although a theoretical formula
was used in the calculations, yet the results have been care-
fully corrected by a comparison both with the observations of
Bradley and with those made with very perfect instruments
in the observatory over which Bessel presides. These two
make together a table of mean refractions of the highest au-
thority; and being free from hypothetical admissions, to
speak with precision, they form the only table of the kind
of which astronomy in its actual state can boast.

The mean refractions, being a fixed set of numbers at any
proposed observatory, are independent of temporary changes
in the state of the air. If the general constitution of the at-

278 Mr. Ivory on the Theory of the Astronomical Refractions.

mosphere were so well known as to enable us to deduce the
temperature, the density, and the pressure at any given alti-
tude, from the observed condition of the air at the earth’s sur-
face, it might be possible to pitch upon an atmosphere inter-
mediate between the extreme cases, in which the irregularities
would compensate one another. From such an atmosphere
the mean refractions used in astronomy might be correctly
computed. But in reality we have no exact knowledge of the
variations to which the air is subject in ascending above the
surface of the earth. The diffusion of heat and aqueous va-
pour, the laws which regulate the density and pressure, are
but slightly and hypothetically known. Many laborious re-
searches in the lower part of the atmosphere, to which access
can be had with instruments, have not been attended with
complete success; and they have thrown no light upon what
takes place in the upper parts. The limit of the atmosphere,
or the height at which the air ceases to have power to refract
light, is uncertain, and is, no doubt, as well as the figure of
the limiting surface, subject to continual fluctuation. Re-
flecting on what is said, it must be evident that the mean re-
fraction of a star, which is a fixed quantity, cannot possibly
be deduced from an atmosphere daily and hourly varying in
its essential properties.

A table of refractions, such as is used in astronomy, con-
tains only mean effects of the atmosphere, that take place at
a given point of the earth’s surface; and they should properly
be compared with other mean effects at the same place. Of
these mean effects a principal one is the height that must
be ascended in the air for depressing the thermometer one
degree, from which another mean effect is easily deduced,
namely, the rate at which the density of the air decreases as
the height increases. The values of these quantities, as o¢-
casionally determined at any particular place, will vary ac-
cording to the actual state of the air; but a multitude of par-
ticular determinations embracing every vicissitude of the at-
mosphere, will at length lead to mean quantities which are
constant, and such as would be observed in the same at-
mosphere that produces the mean refractions.

It is found that the refractive power of air depends on the
density to which it is proportional; and hence the rate at
which the density varies at the earth’s surface, must have a
great influence on the quantity of the astronomical refractions.
It furnishes a key to the scale of the real densities in the at-
mosphere. When a thermometer is elevated in the air, it is
found that the mercury continues to be depressed equally to
great heights; in like manner the decrements of density will

Mr. Ivory on the Theory of the Astronomical Refractions, 279

vary slowly from being proportional to the spaces passed
through ; so that a great share of that part of the astronomical
refraction which depends upon the constitution of the atmo-
sphere must be ascribed to the initial rate at which the den-
sity decreases. This rate is not hypothetical; it isa real
quantity independent of every other; its mean value, which
alone we consider, is as determinate and as much the result
of experiment as is the refractive power of the air: and in a
solution of the problem which is not warped by arbitrary sup-
positions, and which deduces the effect only from causes really
existing in nature, the former quantity will produce a part of
the refraction as certain and unalterable, although perhaps
not so considerable, as the latter.

But although the initial rate of the decrease of density is
an essential element of the astronomical refractions, it may
not alone be sufficient for a complete solution of the problem.
In ascending to great heights above the earth’s surface, the
decrements of density will at length cease to be proportional
to the spaces passed through, or to the variations of tempera-
ture. The refraction of light by the atmosphere is a com-
plicated effect depending upon different considerations: but
the influence of these considerations on the mean refractions
must be uniform and free from fluctuation, and can arise only
from quantities which are constant in their mean values at
any proposed observatory. In speaking of mean quantities
we exclude whatever is hypothetical, and confine our atten-
tion to such only as have a real existence in nature, although
it may not in all cases be possible to obtain exact measure-
ments by direct observation. As the refractions themselves
are capable of being determined experimentally, they may be
‘made the means of ascertaining what is left unknown in the
formula for computing thems; and they may thus contribute
indirectly to advance our knowledge of the constitution of the
atmosphere.

In proceeding to treat of this problem according to the no-
tions that have been briefly explained, it remains to add, that
the mean effects of the atmosphere at the same observatory
(of which mean effects a table of refractions is one) are alone
considered, without at all entering on the question whether
such effects are different or not, at different points of the
earth’s surface. It is very well known that the refractions, to
a considerable distance from the zenith, depend only on the
refractive power of the air and the spherical figure of the at-
mosphere; so far there is no reason to doubt that they are
the same over a great part of the surface of the globe, ac-
cording to the opinion generally held by astronomers ; but,

280 Mr. Ivory on the Theory of the Astronomical Refractions.

at greater zenith distances, when the manner in which the
atmosphere is constituted comes into play, it is not so clear
that they may not be subject to vary in different climates, and
at different localities of the same climate. Ifa table of refrac-
tions at a given observatory contain a set of fixed numbers,
these must be deducible from quantities not liable to change,
that is, from certain mean effects produced by the atmosphere
at the observatory. ‘To trace the relations that necessarily
subsist between the mean effects that take place at a given
point on the surface of the earth, is the proper business of
geometry ; if this can be successfully accomplished, the astro-
nomical refractions will be made to depend upon a small num-
ber of quantities really existing in nature, and which can be
determined, either directly or indirectly, by actual observa-
tion.

1. The foundation of the theory of the astronomical re-
fractions was laid by Dominique Cassini. ‘The earth being
supposed a perfect sphere, ke conceived that it was environed
by a spherical stratum of air uniform in its density from the
bottom tothe top. By these assumptions the computation of
the refractions is reduced to a problem of the elementary
geometry requiring only that there be known the height of
the homogeneous atmosphere, and the refractive power of air.
Let the light of a star S fall upon the atmosphere at B, from
which point it is refracted to the eye of an observer at O on

the earth’s surface DOE: the centre of the earth being at
C, draw the radii COK, CD BH: the angle KOB = 4,
is the apparent zenith distance of the star; and OBC = ¢
is the angle in which the light of the star is refracted on enter-
ing the atmosphere: now from the triangle O B C we deduce

CO

sinOBC = sin KOB x CB:

Mr. Ivory on the Theory of the Astronomical Refractions. 281

af 3 t petri 01! Ds
or, which is the same thing, putting z = Sp’

Again, 4 being the angle in which the light of the star is re-
fracted, if we put 26 for the refraction, the angle of incidence
S BH, which in the present case is always greater than the

2 : i 6 .
angle of refraction, will be = ¢ + 04; and tt) ill
ted b Leo sihesyihat
be a constant ratio represented by Prem wy, so tha
sing © Hh sin $

at Sider) Taiping ane eC
Thus we have the two following equations, which furnish a
very easy rule for computing the mean refractions according
to Cassini’s method, viz.

sin 9
(l+7)V1—2a°
As i and @ are both very small numbers, if we put

sin (¢+86) =

m=t—i’,
: , 3a?
BSt— ew! + at,

the two last equations will become
sin ¢ = sin 6 — msin 6,
sin (¢ + 34) = siné—~n siné:
and by employing the usual formula for deducing the varia-
tion of the arc from the variation of the sine, we get
m2
2

2
¢+ 80 =6—ntand 4+ —— tan? 4;

¢=6—mtan§é + tan? 6,

consequently
m2 —n?

86 = (m— am
(m—mn) tan 6 3

. tan? 6;
that is,
: 3 a? dn a? .
§= (x —ia + oe) tan § — (j2=—) tan® 6;
or, which is the same thing,

(4) = a(1+a) tand (1— ebay,

80 = ate _izie
6 atan§(1+a cos® soy

282 Mr. Ivory on the Theory ofthe Astronomical Refractions.

agreeing exactly with Laplace’s formula employed in com-
puting the first part of the table of mean refractions published.
by the French Board of Longitude.

2. The publication of Newton’s Principia enabled geome-
ters to take a more enlarged view of the astronomical refrac-
tions, and one approaching nearer to nature. According to
Cassini, the atmosphere is a spherical stratum of air, uniform
in its density throughout, diffused round the earth to the
height of about five miles; in reality the density decreases
gradually in ascending, and is hardly so much attenuated
as to be ineffective to refract the light at the great elevation
of fifty miles. The path described by the light of a star in
its passage through the atmosphere is therefore not a straight
line, as it would be in the hypothesis of Cassini, but a curve
more and more inflected towards the earth’s centre by the
successive action of air of increasing density. _Now in the
Principia there is found whatever is necessary for determining
the nature of this curve, and consequently for solving the pro-
blem of the astronomical refractions, which consists in ascer-
taining the difference between the direction of the light when
it enters the atmosphere, and its ultimate direction when it
arrives at the earth’s surface. In the last section of the first
book of his immortal work, Newton teaches in what mamer
the molecules of bodies act upon the rays of light and refract
them; and as the atmosphere must be uniform in its condi-
tion at all equal altitudes, its action upon light can only be a
force directed to the centre of the earth; so that the trajec-
tory in which the light moves, being described by a centripetal
force, the determination of its figure will fall under the pro-
positions contained in the second section of the same book.

Conceive that light falls upon an atmosphere A G K, con-
stituted as Cassini supposed, spherical in its form, concentric

to the earth, of the same
density y throughout; and
suppose that the attractive
force of the molecules of air
situated in the surface AG K
extends to mn on one side,
and to mn’ on the other.
Every molecule of light when
cit arrives at mm wil! be at-
tracted by the air in a direc-
tion perpendicular to the sur-
face A GK, and tending to
C the centre of the earth ; it
will continue to suffer a varied attraction till it penetrates to

=
r

Mr. Ivory on the Theory of the Astronomical Refractions. 288

the other surface m’ n’; but when it has passed this limit, it
will no longer be acted upon effectively by the surrounding
air, which will attract tt equally in all opposite directions. As
the attraction of air extends only to insensible distances, in
estimating its action upon a molecule of light we may consi-
der the limiting surfaces mm and m! n’ as parallel planes, the
forces being perpendicular to mn, and of the same intensity
at all equal distances from it. ‘The law of the forces in action
between mm and m’n! is indetermined ; it may be uniform, or
varied in any manner. These things being premised, it fol-
lows from a fundamental proposition of the philosophy of
Newton, the demonstration of which it would be useless to
repeat here, that the total action of all the forces between m x
and mn! is to add to the square of the velocity of the light
incident at mn, an increment which is always the same, what-
ever be the direction in which the light arrives at mm. Ifwe
now put v for the velocity with which the light enters mn,
and v’ for the velocity with which it leaves m! n’, what is said
will be expressed by this equation,

v2? — y= 2.9 (@),
¢ (¢) denoting the sum of all the forces between mn and m'n',
each multiplied by the space through which it acts, a sum
which, in different atmospheres, will vary only when p varies.

It will be convenient to have a name for the function ¢ (p),
and the most appropriate term seems to be, the refractive
power of the air. In using this term, or in expressing by
¢ (¢) the action of air upon light, it is always supposed that
the light passes out of a vacuum into air of the density @.

A property resulting from what is said may be mentioned.
Having drawn a radius from the centre of the earth to the
point at which the light falls upon the atmosphere, let a de-
note the angle made by the direction of the velocity » with
the radius, and ow’ the angle made by the direction of the
velocity v’ with it; then v sin @ and uv! sin a! will be the
partial velocities of the light parallel to the surface of the
atmosphere. Now these are equal; for all the forces which
change v into vu! are perpendicular to the surface of the at-
mosphere, and therefore they have no effect to alter the ve-
locity of the light parallel to that surface. Thus

using =v sing,
and
sina — vu’

aa ’

sin a v
that is, in words, the ratio of the sine of incidence to the
sine of refraction is equal to the ratio of the velocity of the

284 Mr. Ivory on the Theory of the Astronomical Refractions.

light after refraction to the velocity of the incident light;
which ratio, being independent of the direction of the incident
light, is constant for all light that falls upon the atmosphere
with the same velocity.

What has been said of an atmosphere supposed homogene-
ous is next to be applied to the real atmosphere of the earth,
the density of which decreases continually in ascending. The
sphere MON of which C is the centre, representing the

earth, let SA B O be the trajectory described by light ema-
nating from the star S, in its passage through the atmosphere
to the earth’s surface at O; through any two points of this
curve, A and B, draw spherical surfaces concentric to the
earth, the distances AC and DC from the common centre
being 7 + dr and r. Representing by p the density of the
air above the spherical surface at A, let g + dp stand for the
density, supposed uniform, of the stratum between the two
surfaces at A and B: and it is to be observed that, though
AD = dr is an infinitesimal, it is nevertheless to be accounted
infinitely great when compared to the insensible distance at
which the molecular action of the air at A ceases to act:
from which it follows that the refractive power of the stratum
upon light which enters at A, is exactly equal to the refract-
ive power of a homogeneous atmosphere, supposing the den-
sity p + dp to extend unvaried to the earth’s surface. Now
if v denote the velocity with which the light moves in the
trajectory at A, the refractive power of the air above the stra-
tum will diminish v? by the quantity 2 ¢ (¢); for it is obvious
that the refractive power of the air above the spherical sur-
face at A, is equal and opposite to the refractive power of a
homogeneous atmosphere within the same surface and of the

Mr. Ivory on the Theory of the Astronomical Refractions. 285

density p: on the other hand, the refractive power of the stra-
tum will augment v* by the quantity 2¢(p + dp): where-
fore, upon the whole, the real increment of v? will be 2 ¢ (p
+ dp) —2¢(p) ; so that we shall have
d.vi=2$(p+dp)—2$ (p) =2d.$ (p);
and, by integrating,
ve =n? + 24 (p).

It is obvious that n? is the square of the velocity of the
light before it arrives at the atmosphere, that is, when it
moves ina vacuum. We may consider 7? as the unit in parts
of which the squares of the velocity of the light at the several

points of the trajectory are estimated; which requires that
the formula be thus written,

vu? = 1+ 24 (p).
Resuming the equation

du. = 2d. (2);
we have

= 9 4-O (Pp),

vdv= d.o(p)= ay ed
from which we learn, that the same addition which v? receives
by the refractive power of the air at A, it will acquire by the

accumulated action of the force cae) at all the points of
the line dr, or, which is the same thing, by the action of the
ging the light towards the earth’

SF urging the light towards the earth's centre at all

the points of the curve AB. Thus the path of the light of a

star in its passage through the atmosphere is a trajectory de-

286 Mr. Ivory on the Theory of the Astronomical Refractions.

scribed by the action of the centripetal force — oe tending

to the centre of the earth, the sign — being necessary, be-
cause the analytical expression is essentially negative.

Draw A Ha tangent of the curve at A, B m perpendicular
to A H, and produce CB to meet A H inp: put » for the
angle ACO which the radius vector A C makes with CO
the vertical of the observer; dz for A B the element of the
curve: dr for the time of moving through AB; and R for
the radius of curvature at A. Now Bp is the space through

: , d. A
which the centripetal force — apie would cause a mole-

cule of light to move from a state of rest in the time dr:
wherefore

2Bp = — eae ar 3
dr
also
ee Bm fs ae dz |
P= sin BAD @2R ‘rdn’
and, by equating the equal quantities, we get
2
oe =— Hat to) : aot FOR veoteseae Tle)

The refraction of the light in moving from A to B, or the
difference of the directions of the curve at A and B, is evi-
dently equal to the angle subtended by A B at the centre of

; d
the circle of curvature, that is, to “a : wherefore if 84 re-

present the refraction increasing from the top of the atmo-
sphere to the earth’s surface, we shall have

d.o(p) dx

dp ae
This formula is merely an application of the 6th proposition
of the first book of the Principia.

Another general and useful expression of the differential
of the refraction is easily obtained. Draw C H = y, perpen-
dicular to the tangent A H: from the known properties of
curve-lines, we have

d.8§= —

ran

rar
R= ay
wherefore
dz idee 0 dy
ee =dy dr ' rt Jamy

Mr. Ivory onthe Theory of the Astronomical Refractions. 287

consequently
i aed genni S “3A\ nth Yegle (2.)
V7? — y?

but in this formula @@ must be conceived to increase from the
surface of the earth to the top of the atmosphere.

In applying the last formula it is necessary to have a value
of y. Draw OL to touch the curve at O, and C N perpen-
dicular to OL: put up’’ for the density of the air, and the
velocity of the light at O; also y' for the perpendicular C N,
a for C Othe radius of the earth, and 4 for angle CON,
which is the apparent zenith-distance of the star: we shall
have AreaaABC_ dz

dt an (a
and because the curve is described by a centripetal force
tending to C, the value of v xy will be the same at all the
points of the curve; wherefore

uxy=su xy’:

xy=uv xy:

and
, !

= ° = asingx—
= x —= — ,
Y y U v
Now, according to what was before shown,

v= 71+ 24(p),
'= f1429(p);

2 1+ 24 (p!
y = asin 6x J . eeeoee (3.)

By substituting this expression in the differential of the re-
fraction, the problem will be reduced to an integration.

The equations that have been investigated are perfectly
general, and will apply in any constitution of the atmosphere
that may be adopted. It has been thought better to consider
the manner in which the forces act, than to employ functions
with peculiar properties to express the molecular action.
When the light in passing through the atmosphere arrives
at a surface of increased density, it receives an impulse which
may be considered as instantaneous ; and this impulse being
distributed over the breadth of a stratum of uniform density,
ascertains the centripetal force tending to the earth’s centre,
by the action of which the trajectory is described.

[To be continued]

v

wherefore

[ 288 J

XLV. Memoir of G. Mott, LL.D., Professor of Physical
Sciences in the University of Utrecht, and Member of the
Academy of Brussels. By M. QuEtrELET.*

(THE sciences, like those who cultivate them, enjoy this

happy privilege; that in regard to them there exist no
political barriers, no national antipathies, nor even those kinds
of intellectual frontiers which, under the influence of lan-
guages, become established between the literatures of different
nations. They form a true republic, whose peace nothing
should ever disturb, and where merit alone leads to distinc-
tions, for the conferring of which there are needed no formal
resolves nor protecting regulations. ‘The respectgiven to
talents, like the esteem accorded to virtue, is so inherent in
our nature, that it is not in our power to refuse it when it is
really deserved. As for us, members of this Academy, who,
by our studies and our tastes, find ourselves placed in peace-
ful regions, where the shocks of political dissensions cease to
be felt, we shall see in the philosopher who is the subject of
this memoir only the companion who took his place in the
midst of us, who took part in our labours and aided us by
his knowledge.

Gerard Moll was born at Amsterdam on the 18th of January
1785. His parents, Gerard Moll and Anna Diersen, whose
only child he was, concentrated all their affections in him.
His father was engaged in commerce and was more than
usually well-informed: his mother especially possessed a very
cultivated understanding and a taste for poetry, to which she
applied herself with success; it was she who attended to the
education of her son, and who watched and aided every
dawning of his intelligence. When he entered the schools his
progress was very rapid, and he was scarcely ten years old
before he spoke with facility, not only his mother tongue, but
the French and German languages. He had not neglected
the rudiments of Latin; but as he was intended to a lite of
trade and business, the language of Cicero had to give place
to that of Watt.

The youthful Gerard Moll was placed as an apprentice in

iz From the Annuaire de Bruxelles for 1839. The following note is sub-
oined.
} In writing this memoir we have principally availed ourselves of the
particulars derived from an obituary article published by Professor Van
Rees, (see Nos. 35 and 36 of the Letterbode for 1838) and in the tract,
L. G. Visscher Oratio de Gerardo Moll, read before the University of
Utrecht, the 26th of March 1838. M. Van Rees is one of M. Moll’s
most distinguished pupils, and more than once rendered valuable assistance
to his master, whose worthy rival he had become. No one certainly was

more worthy than M. Van Rees of succeeding him in the duties of pro-
fessor and director of the Observatory of Utrecht.

M. Quetelet’s Memoir of Prof. Moll. 289

one of the commercial houses in his native city. His fre-
quent visits on ship-board, his intercourse with sailors, and
his natural curiosity, soon made him familiar with numerous
particulars connected with the art of navigation, and at the
same time created in him a taste for the mathematical sci-
ences.

To the care of Professor Keyser he owed his initiation in
the secrets of geometry and algebra: in 1801 he began the
study of astronomy, which notwithstanding its utility was at
that time rather neglected in his country ; but it was not till
1804 that his taste for this science decidedly showed itself. He
was then in a commercial house in London, but his inclina-
tion led him far less to the counting-houses of merchants
than to the workshop of the celebrated instrument-maker
Troughton, whose acquaintance he had succeeded in ob-
taining. After a time he had procured a sextant of ten-inch
radius ; and rich in this treasure, he thought henceforth he had
done enough for trade, and resolved to abandon its pursuits.

He now went back to Holland; it was at the time when the
conscriptions decimated the populations of the interior, in or-
der to supply abroad the armies of the empire, which fought in
different parts of Europe with incredible intrepidity and ac-
tivity, and loaded themselves at once with glory, with booty,
and with the curses of conquered nations. ‘The father of
our young philosopher, who felt no ambition that his son
should take part in these conquests, sought for the means of
keeping him at his side, and by destining him for scientific
pursuits thought to find the expedient he wished for. He
caused him therefore to be entered as a student at the
Atheneum of Amsterdam, where the young Gerard eagerly
attended the lectures of Cras and Van Lennep for literature,
and those of the celebrated Van Swinden for the sciences.
His connexion with this latter philosopher completely de-
cided his destination. Our colleague had also made ac-
quaintance with Professor Van Beeck Calkoen; and at his
desire he took part with Professor Keyser in determining the
difference of the meridians of Amsterdam and Utrecht by
means of fire signals made on the top of the tower of Loene*.

It was in 1809 that he took the degree of Candidate. in
Philosophy at the University of Leyden. The following year,
in the month of June, he went to Paris, in order to pursue
his favourite studies with more activity, and upon a greater
theatre. He became acquainted with several distinguished
philosophers, and particularly with Delambre, for whom he
always professed sentiments of lively gratitude and of sincere

' * Letterbode, 1807, i. 21.
Phil. Mag, S, 3, Vol. 14, No. 89, April 1839, U

290 M. Quetelet’s Memoir of Prof. Moll.

attachment. The declining health of his father, who died soon
after, recalled him to his country in the month of February
1812.

Prof. Van Beeck Calkoen had also deceased at Utrecht, and
the chair of mathematical and physical science had become va-
cant. A fear was entertained that it would be suppressed,
through the measures taken by the French government, which
had lowered the University of Utrecht to the rank of a second-
ary school. The influence of Delambre and Van Swinden, how-
ever, were powerful enough to obtain the nomination of our
colleague, first as director of the Observatory of Utrecht, and
some months after as professor of mathematical and physical
sciences. At the reorganization of the University, in 1815,
he obtained the chair of physical sciences that Professor
Rossyn had filled.

The first care of Moli in his new office was given to
putting in order the observatory, which was in a bad state in
consequence of the past misfortunes. The ruins of an old
isolated tower situated on one of the ramparts of the town
had been made use of for the construction of this scientific
establishment. ‘The wisest plan no doubt would have been
to demolish this elevated building, which had neither the re-
quisite solidity, nor suitable conveniences; but money was
wanting, and the success of this observatory was completely
compromised. In vain did the new director fix in succes-
sion a choice of the finest instruments which he had been
able to procure in the different visits he made to England
and Germany; all his efforts failed before difficulties which
taken separately would have been of little importance, but
the combination of which could not but, in the long run,
operate most unfavourably. The first of these disadvantages,
and perhaps the most serious, was the distance from home
that the astronomer had to go to the place for his observa-
tions. A small and inconvenient spot, elevated and by no
means firm bases, which would only admit of instruments of
inferior dimensions, and of taking in hand a restricted num-
ber of observations, presented obstacles which ended without
doubt in quite subduing the zeal which our colleague had
shown at the beginning of his enterprise. ‘The number of his
astronomical labours were indeed few; he published only
his observations of the comet of 1819 *, and those of the
transit of Mercury over the sun in the month of May 18327;

* Letterbode, 1819, i. 59.

+ T. iv. 71. of the Memoirs of the Ist class of the Institute of the Low
Countries.

M. Quetelet’s Memoir of Prof. Moll. 291

he also communicated to the Royal Astronomical Society of
London, the whole of the observations that were made in
Holland of the fine eclipse of the sun in September 1820, at
which time M. Moll was himself in England*. The preceding
year, when he resigned the rectorate of the University of
Utrecht, he had published a Latin dissertation on the ulterior
progress of astronomy, which is inserted in the annals of this
learned body.

That which, moreover, seems to have contributed most to
turn aside our colleague from his astronomical labours was
the versatility of his mind, which loved to spread itself at once
over a great number of objects; it was this desire of change of
place and of keeping pace with the progress of science, which
led him to visit his neighbours, and especially the English, as
often as his duties of professor allowed him, and we should
add, almost always longer than these duties permitted. The
government, however, wel] understood that the inconveni-
ences which resulted from this were very trifling in compari-
son with the advantages to be derived from these repeated ex-
cursions, and had the wisdom to wink at what might be irre-
gular in his conduct as professor. As a natural philosopher
Moll was truly at home; there are labours of his which can
leave no doubt in this respect; but the service in which he
has been most especially useful to his country was in keep-
ing her acquainted with all that was doing abroad, not only
in the sciences, but in all the uses to which they may be applied
for the wants of society. Was any important discovery made,
any useful improvement, he not only hastened to communicate
it in lectures and in the scientific societies to which he be-
longed, but he endeavoured through the journals to make
the results comprehensible to the generality of readers; thus,
navigation by steam-boats, artesian wells, warming hot-houses
by steam, submarine discoveries by the diving-bell, the con-
struction of lightning conductors, each in its turn found in
him a zealous patron always disposed to make their advan-
tages available}. He loved especially to throw light on
the scientific subjects, so to speak, in the order of the day,
and to which circumstances gave an interest; thus, imme-
diately after the burning of a part of the beautiful church of
St. Bavon at Ghent, he presented his remarks on the im-
provement of fire-engines. On the subject of horse-races, he
communicated in a notice a statement of the swiftness of horses
of different countries and of different breeds. If any remark-

* Vol. i. 144, Memoirs of the Royal Astronomical Society.
+ Memoirs on these different subjects have been inserted by M. Moll
in the Letterbode and in the Mémoires de la Société de Haarlem.
U2

292 M. Quetelet’s Memoir of Prof. Moll.

able change in the atmosphere occurred, he took the oppor-
tunity of communicating his observations on this subject, and
of calling to mind. the analogous phenomena which had
formerly taken place. These services in detail greatly con-
tributed to make his name popular with his countrymen.

M. Moll was the soul of all the scientific commissions that
the government formed, and it must be allowed that he was
able to render more useful services than in his little observa-
tory, where indeed for a long time the only help he had was
his porter.

Immediately after the formation of the kingdom of the
Netherlands, the system of weights and measures had to be
settled, and M. Moll was one of the principal members of
the commission employed in this work. In this instance the
government bestowed on him a mark of its satisfaction by
giving him the title of knight of the order of the Belgic Lion,

He had above all an opportunity of affording proofs of his
practical knowledge in the commission which was employed
to make a report on the state of the waters, and of their
drainage, in the northern provinces. The work required was
difficult and of the highest importance. Every one knew
that the bed of the rivers was imperceptibly raised in Hol-
land, and that their mouths were filling more and more with
sand; but opinions were singularly divided upon the means
of remedying an evil which tended some time or other to
swallow up a considerable portion of the country. Some ad-
vised giving more elevation and weight to the dykes; others
advised lowering them; others in fine were of opinion that
channels of drainage should be made laterally; but they dif-
fered among one another on the means of executing this no
less than the former. The commission was therefore em-
ployed to examine all these projects, and to propose such
plans for the security of the country as should unite financial
interests with those of commerce and industry. This labour
of our colleague lasted four years, and he gave his time al-
most exclusively to it. He was appointed the reporter of
the commission, and all are agreed in regarding his work,
which was printed in 1827, as a model of order, clearness,
and judgement.

In 1826 he had been nominated on another commission for
the amelioration of marine charts, and for the examination of
officers. He was no less useful in these new duties; for,
as we before noticed, from his childhood he had been na-
turally led to the study of navigation and all that is con-
nected with it. This branch of knowledge was the more con-
genial to his taste because it was intimately connected with

M. Quetelet’s Memoir of Prof. Moll. 293

the causes of the prosperity and the glory of Holland; and M.
Moll was no less a good patriot than an enlightened philoso-
pher. His work on the early maritime expeditions of the
Netherlands, Vroegere Zeetogten der Nederlanders, is a na-
tional work full of curious and useful inquiries, and breathing
the purest love of country. Whilst setting forth the immense
services rendered to navigation by Dutch voyagers, the author
is far from contenting himself with emphatic praises ; on the
contrary, he reproaches his fellow-citizens for having fallen
off from the condition to which their ancestors had raised
them, and encourages them to strive to regain their ancient
splendour.

We owe to him also some interesting notes with which he
enriched the work of M. Van Kampen* on the history of the
sciences in the Netherlands}. His scientific acquirements
and his taste for literature naturally led him into the domain
of history. Influenced at the same time by sentiments of
gratitude, he wrote in succession biographical notices on De-
Jambre, Keyser, and Van Swinden, who had been his masters ;
he also paid a tribute of esteem to the memory of Delaplace
and Wollaston, with whom he had been intimate. During
the latter part of his life he was occupied about a memoir of
our old colleague and his countryman the baron Van Uten-
hoven, and which must have been printed subsequently.

When the government, in 1835, resolved, at the request of
the English government, and in aid of the labours of Messrs.
Whewell and Lubbock, to cause a series of observations to
be made upon the hours and height of the tides along the
coasts of Holland, it was to M. Moll also that the care of
directing and superintending them was entrusted. In volume
vii. of the Memoirs of the 1st class of the Institute may be seen
the report which was made on this subject. This undertaking
could not have been placed in better hands than those of the
philosopher, who, at a former period, had furnished the most
judicious remarks upon the placing of the standard scale em-
ployed to mark the height of the level of the sea before Am-
sterdam (het Amsterdamsche pel).

It remains for me now to speak of the labours of M. Moll
in the physical sciences. ‘The situation of this philosopher
afforded him considerable advantages, of which he knew how
to avail himself with skill. Beside the collections of the ob-

[* We just learn, with sincere regret, that science has sustained
another severe loss in the death of this distinguished professor, in the
prime of life, the very day before Oxford sustained a similar loss in the
death of the honourable and excellent Rigaud.—Eprr. }

+ Bijdragen tot de geschiedenis der wetenschappen in Nederland,

294 M. Quetelet’s Memoir of Prof. Moll.

servatory and those of the cabinet of natural philosophy of
the university, which by his care had increased considerably,
he had also at his disposal the collections of the society of sci-
ences of Utrecht, which were notless rich. A circumstance
very honourable for our colleague enabled him to add still more
to the treasures that he had at command: by the death of Pro-
fessor Ekama, in 1826, the chair of physical sciences in the
university of Leyden had become vacant, and the curators of
this establishment had made an overture to Moll to induce
him to fill it. ‘These honourable offers had not been posi-
tively rejected ; but the university of Utrecht felt that their
honour and interest would be compromised by permitting a
philosopher who shed so much lustre upon it to remove.
M. Moll yielded to the solicitations addressed to him by the
university, and resolved to remain in his situation. The city of
Utrecht wished to present him with a testimony of its grati-
tude; but our colleague refused to accept anything for him-
self, he only expressed a desire to see something done for the
interests of science, and the government of the city placed at
his disposal the sum of ten thousand florins for the purchase
of instruments.

One of the most important labours of M. Moll was that
which he accomplished in conjunction with M. Van Beek
upon the velocity of sound. The experiments of these philo-
sophers took place in 1823, a year after those which were
made by a commission of the Bureau of Longitude of France,
composed of MM. Arago, Gay-Lussac, De Humboldt, &c.
The government placed at their disposal all the necessary
means of execution; and the base that the sound had to
traverse extended over a length of 17,000 metres, between
Kooltjesberg near Naarden and the elevation named the
Seven Trees (zeven boomen), near Amersfort. Six nights were
devoted to these experiments, which were made with a care
which seemed to leave nothing to be desired. ‘The results of
them were recorded in the Memoirs of the Institute of the
Low Countries*. The Royal Society of London, by insert-
ing them in its Transactions, also proved the interest it at-
tached to them.

M. Delaplace had also advised them to communicate their
labours to the Bureau of Longitude; and I myself was en-
trusted with a letter, in which that illustrious philosopher
obligingly invited the professor of Utrecht to make this com-
munication.

The inquiries of GErsted, in 1819, relative to the action which

* Mémoires de U Institut des Pays Bas, vii. 281; and Philosophical
Transactions, I. 823. 2nd part.

M. Quetelet’s Memoir of Prof. Moll. 295

an electric current exercises on the magnetic needle, opened
a new field, upon which the philosophers of all nations eagerly
entered, and which soon, thanks to their united efforts, was
as much cultivated and as productive as any other part of the
vast domain of natural philosophy. Our colleague was not
one of the last to put his hand to the work, and he communi-
cated in the Journal de Physique* the different results at
which he had arrived by repeating and extending the experi-
ments of the Danish physicist. He endeavoured to show that
there is a difference of action in chemical and magnetic phe-
nomena, according as the electricity is developed by simple
contact, or by the apparatus of Wollaston. He was occupied
for several years in these researches.

The English experimentalist Sturgeon had made known,
in 1826, that a bar of soft iron bent into the form of a horse-
shoe and covered with a spiral wire of copper, becomes a
powerful magnet as soon as the extremities of the wire are
placed in contact with the poles of a galvanic pile, and that
it instantaneously loses its power as soon as the contact ceases.
In an experiment made in England, and at which M. Moll
was present, one of these temporary magnets bore nine
pound weight. Our colleague resolved to make the experi-
ment on a larger scale. For this purpose he used a plate of
zinc of a surface of eleven square feet, dipping into a nar-
row copper vessel, and he put the poles of this element of
a galvanic pile in connexion with the ends of a copper wire
rolled 83 times around a soft iron bent into the form of a
horse-shoe and weighing five pound. As soon as the con-
tact was established the iron was able to bear 50 pound,
and it was even possible to carry the charge to 76 pound.

Not content with these first results, M. Moll had an iron
constructed of 29 pound weight; and with the same galvanic
element which he had used at first he made it bear 295.

I repeated these different experiments with M. Lipkens,
inspector-general of ordnance; the results to which we came
have been recorded, together with an extract from M. Moll’s
work, in volume vi. of the Correspondance Mathématique,
p: 327. We were at the same time led to investigate the
most advantageous proportions which it is proper to give
to the horse-shoe and to the voltaic element in order to pro-
duce the maximum of effectt. Expressing his desire to see

* By M. De Blainville, v. xcii. p. 295, 309 and 311.

+ Correspondance Math., vol. vii. p. 54, and following. This is perhaps
the place to complain of an error in an Italian Journal, made to the
prejudice of our colleague. In page 63 and following of vol. iii. of the
Annali delle Scienze of Padua, we read an article directed against the

296 M. Quetelet’s Memoir of Prof. Moll.

fresh inquiries made upon this interesting subject, Moll re-
plied to this appeal, by quoting some of his experiments
which we had not had it in our power to become acquainted
with on account of the state of war which existed between the
two countries, and by producing new results obtained by
means of very small elements*.

We owe to M. Moll several other labours in the depart-
ment of physical science, and amongst others a memoir on
reflecting telescopes}, a subject which engaged much at-
tention at that time in Holland, as we have mentioned in
our memoir on the Baron Van Utenhoven{; researches on
the degree of temperature at which water reaches its maxzmum
of density §; comparative observations between the kilogram
and Dutch, English, and other weights |].

At the time when there appeared in England a work 4
which made a great noise because several of the first scientific
men were attacked in it without reserve, Moll undertook the de-
fence of the injured party, and declared himself its champion.
His publication on this subject was entitled ‘* On the alleged
Decline of Science in England, by a Foreigner **.” If we con-
sider the eminent services rendered to science in general, and
to the applied sciences in particular, by the English nation,

Annales de Physique of MM. Arago and Gay-Lussac, and against the Cor-
respondance, for not having mentioned, relative to the subject of M. Moll’s
labours, the inquiries of Professor Dal Negro, which, it is said, were pre-
sented to the Academy of Padua the 21st of June and the 10th of July
of the year 1831. Now, a single word must put an end to these charges,
founded, as we would fain believe, upon an accidental error of date. The
experiments of Moll were communicated to the Institute of Amsterdam
the 30th of January 1830, and published immediately after by this learned
. body under the title of Electro magnetische proeven, in 8vo, by Muller,
Amsterdam, 1830. The results of them were recorded not only in the
Correspondance Mathém. of 1830, and in the Annales of MM. Arago and
Gay-Lussac, but also in the Bibliotheque Universelle, v. xxxxv. p. 19 ; in
the Edinb. Journal of Science, No. vi. v. iii. p. 289 ; in the Journal of the
Royal Institution, 1831, p. 379, &c. Should we not be right in replying
to the Jtalian author in his own words, leaving him to be responsible
for whatever they contain that is bitter and disdainful? Prima di fare
altri experimenti, dovra studiare le cose gia pubblicate in Olanda, in Francia,
in Inghilterra, in Genova, etc.

* Brief betrekkelijk eene aanmerking van den heer Quetelet, Letterbode,
1833, i. 82. et Bibl. Univ. June 1833.

+ Mém.de Institut des Pays-Bas, \st class, i. 29.

+ Annuaire del Académie de Bruvelles for 1838, p. 64.

§ Bijdragen tot de Nat. Wetens., i. 241. || Zoid, vi. 119.

§ On the Decline of Science in England. By Ch. Babbage, 8vo, 1830.

** London, 1831. [As our national honour and gratitude are concerned
in the diffusion and preservation of this able and interesting Tract, which
had but a very limited circulation, we take this opportunity to apprise our
readers that copies are to be had of Mr. Wacey, successor to Boosey,
Broad-street, and at the office of the Philosophical Magazine.—Euz. ]

M. Quetelet’s Memoir of Prof. Moll. 297

we cannot but approve the generous warmth which induced
our colleague to compose his work. With regard to ourselves,
we are certainly far from adopting the judgements of the En-
glish author on some of his countrymen; and the sincere
friendship which we feel for him has made us regret to find
often too much asperity where matters of science were the only
subjects of discussion; at bottom, however, we can see in
it only one of those freaks which men of superior talent some-
times allow themselves to play, and the particular object of
which is to stimulate the ardour of a nation. These are some
of those family reproaches which strangers should not take
for serious.

M. Moll however had much to congratulate himself upon
in his relations with the English philosophers, who had given
him multiplied proofs of their esteem. He belonged to many
of their learned societies, and in 1835, at the meeting of the
British Association at Edinburgh, he was made a member of
it, at the same time that the university offered him the de-
gree of doctor of laws, honoris causa, and that the freedom of
the city was conferred on him; the following year the meet-
ing took place in Dublin, and the university of that city also
presented him with a diploma of doctor of laws.

The upright and firm character of M. Moll, his generally
polite manners, and his obliging disposition, had obtained for
him numerous friends both in his own and in other countries ;
his tastes drew him towards the English, for whom he strongly
expressed his lively sympathy. He may perhaps be blamed,
on the other hand, as yielding sometimes, when individuals
were in question, to prepossessions, which did not influence

-him in matters of science; and these prepossessions were
the more apparent as they were evinced in a somewhat rough
and pungent manner *.

Moll was named member of our Academy the 7th of May,
1828: he had given us reason to hope from him an active
cooperation in our labours, but the political events which en-
sued gave him but small opportunity of realizing his pro-
mises.

The 11th of December 1837, our colleague celebrated the
twenty-fifth anniversary of his professorship; his colleagues,
his pupils, and his numerous friends gave him touching proofs
of their attachment and esteem upon this occasion. But this
day, devoted to pleasure, which consecrated so remarkable an

* Mollium in dijudicandis aliis semper equitate ductum fuisse, nolo
equidem effari. Hoc quidem dicere oportet, equum judicem eum extitisse
si non cunctis, certe multis, optimis, in primis vero senibus et praeceptori-
bus suis. Oratio de G, Moll.

298 Prof. Sylvester on Double Definite Integration,

epoch of his academic career, was destined also to mark its
termination. M. Moll died thirty-seven days afterwards, on
the 17th of January 1838, in his native city, and at the house
of his friend M. F. A. Van Hall, where he had gone to spend
his winter holidays. His remains, according to his desire,
were carried to Amerongen, where also repose those of his
mother. According to his will, his instruments, and his library,
which was very rich, were bequeathed to that university, of
which he had been one of the chief supports.

A. QUETELET.

XLVI. A Note on Definite Double Integration, supplementary
toa former paper on the Motion and Rest of Fluids. By J.
J. Sytvester, Professor of Natural Philosophy in Univer-
sity College, London.*

EK a paper on Fluids which appeared in the December
Number of this Magazine, I had occasion to remark,
that the mass of an area having at the point (2, y) a density
I Mallee Aa
dx e dy

) d dx ,
f: { u a _ ve las; L being the length, and ds an

element of the bounding curve: this may be thought to re-
quire some explanation.

could be expressed by the simple formula

Fig. 1.

1. Let AP Bq represent
any oval.

PpL, Aq M any two contiguous ordinates cutting the curve
in Pp Qq respectively, AC, BD the two extreme tangents
parallel to Og, and ¢ the density at any point (,y). The
expression {fe d 2 dy will serve to denote the mass of the
oval area Ap Bq, and the limits may be twice taken, i. e.
1. the two values of y corresponding to any one of x; and,
2. the two values of a corresponding to C and D. This

* Communicated by the Author.

supplementary toa Paper on the Motion of Fluids. 299

method is in fact tantamount to taking the sum of the columns
P p, gQ; but this is not necessary, for Ap Bg may be con-
sidered as the algebraical sum of the mixtilinear area A P Q
BDC, and the mixtilinear area BD C Apg, or (if any line
O’C D’ be drawn parallel to OCL MD) of APQBD'C
and B D'C' Apgq.

Thus then the mass = fda(/edy),/edy being left in-
determinate, and the extremity of x travelled round from C
to D, and back again from D to C.

This will be better expressed by transforming the variable,
and summing with respect to some quantity, such as the are
of the curve, which continuously increases, or if we please,
with respect to 4, the angle subtending any point taken within
the curve,

The mass is then = +f. ait (fo dy). ee , always

remembering that no constant need be added to fed y, and
that the doubtful sign arises from the choice of ways in which
§ may be measured round. If the area be not included by
one line; but by several, as for example, by a curve and a
right line, the above integral, if broken up into as many parts
as there are breaches of continuity, will still apply.

2. Let us suppose that we have two areas exactly coincid-
ing with, and overlapping one another ; but the density of the
one at (2, 7) to be e, and of the other @’.

Let the mass of the first be treated as the sum of columns
parallel to Oy, and that of the second as the sum of columns
parallel to O x.

The one will be represented by + Hi : ad (fp dy) ve

r dy ty
the other will be represented by + S; a dbf (pdx) aa

and the sum of the two, or the joint mass, by
70 dx oO , dy
£ fe aM Seay) H+ [> as (fe dx}

So long as these two operations are performed separately,
the doubtful signs may be preserved in each term, because s
need not be travelled round in the same direction for the two
summations; but if we perform the second integration con-
jointly for the two masses, their sum

= + fi aod (Se dy} + 2 (Sean) @

the mark of interrogation denoting that one or the other, but

300 ° Dr. Lhotsky’s Notice of a Mineral Spring

not either of the signs + must be used, and the question iss
which ?

This will be answered by taking different points in the
bounding line, which may be continuous or not. Now every
line returning into itself, whether continuous or not, will natu-
rally divide with respect of any given system of axes, into
at most four parts, or sets of parts; two in which dz and dy
both increase or both decrease, and two in which one increases
and the other decreases.

Take P,,. Pes Pa tP4 any
points in the four quadrants
respectively, it will be ob-
served that,

0

At P, the p column enters additively, and the p’ column
subtractively.

At P, both columns are additive.

At P, the p! column is additive and the p column subtrac-
tive.

At P, both columns enter subtractively.

Again, reckoning round in the direction of the arrows,

At P,, vand y are both increasing.

At P., 2 is increasing and y decreasing.

At P., z and y both decrease.

At P,, x is decreasing and y increasing.

Thus when /(p dy) and /(p’ dz) are affected with the same
signs, dx and dy are of opposite signs; and when /p d y,
JS? dx are of opposite signs, dx and dy are of the same sign.

Hence it appears that the mass of the area, whose density
at (2, y) is p + p’, V is capable of being represented by

XLVII. Notice of a Mineral Spring, Menero Downs, N. S.
Wales. By Dr. F. Luotsxy, late of the C. S. Van Diemen’s
Land.*

P the small tract of country as yet known of New Holland,

a number of interesting facts relating to mineralogy and

* Communicated by the Author.

in New South Wales. 301

geology have been discovered, although geology being but a
new science in Europe, has but very lately reached that newest
continent. The burning mountain described by Mr. Wilson,
the remains of a crater seen by Major Mitchell, and the mi-
neral spring I am about to notice are among the most inter-
esting data in this department.

The spring is situated 300 miles from Sydney, amongst ex-
tensive uninhabited downs, which skirt the Australian Alps on
their eastern side. The formation about the spring is calca-
reous, and the immediate neighbourhood of it is formed by
an extensive level of travertine, just like that with which the
plains of Romagna are covered. ‘The spring forms (after
having been enlarged by me) an aperture of 3! diameter, and
the water is of a nearly constant temperature of 50° Fahr.,
although the air was, during my short stay, at 98°. The water
is perfectly clear, and only disturbed by the continual evolu-
tion of carbonic acid gas, with a large quantity of which the
water is saturated. This having been subjected by me to
evaporation, a salt was obtained, which has been examined by
Professor Daubeny of Oxford, who has given the results,
which will be found at the conclusion of the present notice.
The water has the taste of Seltzer water, and was examined
shortly after my return from the Australian Alps, in the
Civil Hospital of Sydney, by the Colonial Surgeon, and other
qualified persons. Its chemical ingredients when ascertained
by the application of the usual tests, very nearly correspond
to those found by Prof. Daubeny in the salt.

I will mention a curious geological occurrence on the pre-
sent occasion. The level of travertine before alluded to is
covered with a white salt, efflorescing therefrom, and which,
conjointly with the fragments of travertine strewed about, gives
the whole locality the appearance as if some extensive build-
ings had been going on, and the plasterer just left off work-
ing. Caves, which contain bones, occur in the vicinity of the
spring.

The following is the memorandum of Prof. Daubeny :

“<The salt which you described as efflorescing nearachemical
spring in Australia, contains carbonate of lime, common salt,
a little sulphate of soda, and some peroxide of iron. The salt
which you represented as being procured by the evaporation
of the water, contains muriates, calcareous earth in combina-
tion with carbonic acid, a trace of magnesia, and iron.”

I have a bottle of the water, which (like those examined in
Sydney) was hermetically sealed at the mouth of the spring,
to be kept for analysis.

302

XLVIII. Proceedings of Learned Societies.

GEOLOGICAL SOCIETY.

Jan. 9,— NOTICE was first read on the discovery of the Basilo-
1839. saurus and the Batrachiosaurus, by Dr. Harlan.
The first remains of the Basilosaurus, which came under Dr.

Harlan’s notice, were a vertebra and some other bones found in the

marly banks of Washeta river, Arkansas territory. In the autumn

of 1834, he examined another collection discovered in a hard lime-

stone in Alabama, and consisting of several enormous vertebre, a

humerus, portions of jaws with teeth, and some other fragments sup-

posed to belong to the same animal. In the matrix of the vertebra
from the Washeta river was a fossil Corbula, common in the Alabama
tertiary deposits, and specimens'of Nautilus, Scutella, and Modiolus of
extinct and new species; sharks’ teeth have also been found in a similar
rock in the vicinity of the locality from which the other collection
was procured. Dr. Harlan was originally inclined, from the struc-
ture of the teeth, to consider these fossil remains as having belonged
to a marine carnivorous animal; but from an examination of the

bones he was induced to conclude, that they were portions of a

new genus of Saurians, for which he proposed the name of Basilo-

saurus.

Dr. Harlan then briefly described a portion of an upper jaw of a
Saurian discovered by a beaver-trapper, on or near the banks of the
Yellowstone river, in the territory of the Missouri, imbedded in a
hard blue limestone rock. On first inspection Dr. Harlan believed,
from the structure of the teeth, the mode of dentition, and the po-
sition of the anterior nares, the fragment belonged to an Ichthyo-
saurus ; but as it differs entirely from that genus in having separate
alveoli, and in the form and position of the intermaxillary bones,
while it approaches in the latter characters the batrachian reptiles,
he has formed for the fossil a new genus designated by the name of
Batrachiosaurus.

A paper was afterwards read, entitled, “ Observations on the
Teeth of the Zeuglodon, Basilosaurus of Dr. Harlan,” by Richard
Owen, Esq., F.G.S., Hunterian Professor in the Royal College of
Surgeons, London.

During the recent discussions respecting the Stonesfield fossil
jaws, one of the strongest arguments adduced and reiterated by
M. de Blainville and others in support of their saurian nature, was
founded on the presumed existence in America of a fossil reptile
possessing teeth with double fangs, and called by Dr. Harlan the
Basilosaurus. To the validity of this argument, Mr. Owen refused
to assent, until the teeth of the American fossil had been subjected
to a re-examination with an especial view to their alleged mode of
implantation in the jaw; and until they had been submitted to the

Geological Society. 303

test of the microscopic investigation of their intimate structure
with reference to the true affinities of the animal to which they be-
longed. The recent arrival of Dr. Harlan in England with the fossils,
and the permission which he has liberally granted Mr. Owen of
having the necessary sections made, have enabled him to determine
the mammiferous nature of the fossil.

Among the parts of the Basilosaurus brought to England by Dr.
Harlan, are two portions of bone belonging to the upper jaw ; the
larger of them contains three teeth; the other, the sockets of twoteeth.
In thelarger specimen, the crowns of the teeth aremore or less perfect,
and they are compressed and conical, but with an obtuse apex. The
longitudinal diameter of the middle, and most perfect one, is three
inches, the transverse diameter one inch two lines, and the height
above the alveolar process two inches and a half. The crown is trans-
versely contracted in the middle, giving its horizontal section an
hour-glass form; and the opposite wide longitudinal grooves which
produce this shape, becoming deeper as the crown approaches the
socket, at length meet and divide the root of the tooth into two se-
parate fangs. ‘The two teeth in the fore part of the jaw are smaller
than the hinder tooth, and the anterior one appears to be of a sim-
pler structure.

A worn-down tooth contained in another portion of jaw, Mr. Owen
had sliced, and it presented the same hour-glass form, the crown
being divided into two irregular, rounded lobes joined by a narrow
isthmus or neck. The anterior lobe is placed obliquely, but the
posterior parallel with the axis of the jaw. The isthmus increases
in length as the tooth descends in the socket until the isthmus finally
disappears, and the two portions of the tooth take on the character
of separate fangs. It is evident that the pulp was originally simple,
but that it soon divided into two parts, from which the growth of
the ivory of the teeth proceeded as from two distinct centres, now
separately surrounded by concentric striz of growth, the exterior
sending an acute-angled process into the isthmus. The cavitas
pulpi, which is very small in the crown of the tooth, contracts as the
crown descends, and is almost obliterated near the extremity, proving
that the teeth were developed from a temporary pulp.

The sockets in the anterior fragment of the upper jaw are indistinct
and filled with hard calcareous matter, but a transverse horizontal
section of the alveolar margin proves, that these sockets are single,
and that the teeth lodged therein had single fangs. In the anterior
socket, there is an indication of the transverse median contraction,
showing that this tooth resembled in form, to a certain degree, the
posterior tooth. A plaster cast of a portion of the lower jaw af-
forded the only means of studying this part of the fossil. It con-
tains four teeth, of which the two posterior are nearly contiguous,
the next is at an interval of an inch and a half, and the most an-
terior of two inches from the preceding. ‘The last tooth is more sim-
ple in form than those behind, and it has been described as a canine.
This fragment of the lower jaw thus confirms the evidence afforded
by the fragments of the upper jaw, that the teeth in the Basilosaurus

304 Geological Society.

were of two kinds, the anterior being smaller and simpler in form,
and further from each other than those behind.

Mr. Owen then proceeds to compare the Basilosaurus with those
animals which have their teeth lodged in distinct sockets, as the
Sphyrzena, and its congeners among fishes, the Plesiosauroid and Cro-
codilean Sauria, and the class Mammalia; but as there is no instance
of either fish or reptile having teeth implanted by two fangs in a
double socket, he commences his comparison of the Basilosaurus
with those Mammalia which most nearly resemble the fossil in other
respects. Among the zoophagous Cetacea the teeth are always si-
milar as to form and structure, and are invariably implanted in the
socket by a broad and simple basis, and they never have two fangs.
Among the herbivorous Cetacea however, the structure, form, num-
ber and mode of implantation of the teeth differ considerably. In
the Manatee, the molars have two long and separate fangs lodged
in deep sockets, and the anterior teeth, when worn down, present
a form of the crown similar to that of the Basilosaurus, but the
opposite indentations are not so deep; and the entire grinding sur-
face of the molars of the Manatee differs considerably from those of
the Basilosaurus, the anterior supporting two transverse conical
ridges, and the posterior three. The Dugong resembles more nearly
the fossil in its molar teeth; the anterior ones being smaller and
simpler than the posterior, and the complication of the latter being
due to exactly the same kind of modification as in the Basiloraurus,
viz. a transverse constriction of the crown. The posterior molar
has its longitudinal diameter increased, and its tramsverse section
approaches to the hour-glass figure, produced by opposite grooves.
‘There is in this tooth also a tendency to the formation of a double
fang, and the establishment of two centres of radiation for the calci-
gerous tubes of the ivory, but the double fang is probably never com-
pleted. The teeth in the Dugong moreover are not scattered as in
the Basilosaurus.

Mr. Owen then briefly compared the teeth of the fossil with
those of the Saurians, and stated that he had not found a single
instance of agreement in the Basilosaurus with the known dental
peculiarities of that class. From the Mosasaurus the teeth of
the American fossil differ in being implanted freely in sockets and
not anchylosed to the substance of the jaw ; from the Ichthyosaurus
and all the lacertine Sauria in being implanted in distinct sockets, and
not in a continuous groove; from the Plesiosaurus and crocodilean
reptiles from the fangs not being simple and expanding as they de-
scend, but double, diminishing in size as they sink in the socket,
and becoming consolidated by the progressive deposition of dental
substance from temporary pulp in progress of absorption. In the
Enaliosauria and the Crocodilia, moreover, there are invariably two
or more germs of new teeth in different stages of formation close to
or contained within the cavity of the base of the protruded teeth ; but
the Basilosaurus presents no trace of this characteristic Saurian
structure. From the external characters only of the teeth, Mr. Owen
therefore infers, that the fossil was a Mammifer of the cetaceous

—

Geological Society. 805

order, and intermediate to the herbivorous and piscivorous sections
of that order, as it now stands in the Cuvierian system.

In consequence however of the Basilosaurus having been re-
garded as affording an exceptional example among Reptilia of teeth
having two fangs, though contrary to all analogy, and as the other
characters stated above may be considered by the same anatomists
to be only exceptions, Mr. Owen procured sections of the teeth for
microscopic examination of their intimate structure and for com-
paring it with that of the teeth of other animals.

In the Sphyrzna and allied fossil fishes which are implanted in
sockets, the teeth are characterized by a continuation of medullary
canals, arranged in a beautifully reticulated manner, extending
through the entire substance of the tooth, and affording innumerable
centres of radiation to extremely fine calcigerous tubes.

In the Ichthyosaurus and Crocodile the pulp cavity is simple and
central, asin Mammalia, and the calcigerous tubuli radiate from
this centre to every part of the circumference of the tooth, to which
they are generally at right angles. The crown of the tooth in these
Saurians is covered with enamel, while that part of the tooth which is
in the.alveolus is surrounded with a thick layer of cortical substance.
In the Dolphins which have simple conical teeth like the higher
reptiles, the crown is also covered with enamel and the base with
cementum. But in the Cachalot and Dugong the whole of the
teeth is covered with cementum. In the Dugong this external layer
presents the same characteristic radiated purkingian corpuscles
or cells as in the cementum of the human teeth, and those of other
animals ; but the cementum of the Dugong differs from that of the
Pachyderms and Ruminants in being traversed by numerous calcige-
rous tubes, the corpuscles or cells being scattered in the interstices
of these tubes. Now the crowns of the teeth of the Basilosau-
rus evidently exhibit in many parts a thin investing layer of a
substance distinct from the body or ivory of the tooth, and the mi-
croscopic examination of a thin layer of this substance proves it to

ossess the same characters as the cementum of the crown of the
tooth of the Dugong. The purkingian cells are, in some places,
scattered irregularly, but in others are arranged in parallel rows.
The tubes radiating from the cells are wider than usual at the com-
mencement; but soon divide and subdivide, forming rich reticula-
tions in the interspaces, and communicating with the branches of the
parallel larger tubes. These are placed, as in the Dugong, perpen-
dicular to the surface of the tooth, but theyare less regularlyarranged
than the calcigerous tubes of the ivory, with which, however, they
form numerous continuations. ‘There is a greater proportion of cz-
mentum in the isthmus of the tooth than elsewhere ;_ and the worn-
down crown of the tooth must therefore have exhibited a complicated
structure. ‘Ihe entire substance of the ivory of the teeth consists
of fine calcigerous tubes radiating from the centres of the two lobes,
without any intermixture of coarser medullary tubes which charac-
terize the teeth of the Iguanodon; or the slightest trace of the re-
ticulated canals, which distinguish the texture of the teeth of the

Phil. Mag. S. 3. Vol. 14. No. 89. April 1839. ».4

306 Geological Society.

Sphyrena and its congeners. The calcigerous tubes undulate regu-
larly, and, like those of the Dugong, exhibit more plainly the pri-
mary dichotomous bifurcations, and the subordinate lateral branches
given off at acute angles: they also communicate with numerous
minute cells arranged in concentric lines.

Thus, the microscopic characters of the texture of the teeth of the
great Basilosaurus are strictly of a mammiferous nature; and Mr.
Owen further showed that they differ from those of the fossil Eden-
tata, which are also surrounded by cementum, in the absence of the
coarse central ivory ; and confirm the inference respecting the position
of the fossil in the natural system drawn from the external aspect of
the teeth.

Mr. Owen then adduced further proofs of the mammiferous and
cetaceous. character of the Basilosaurus, from the structure of the
vertebra, which proves that the epiphyseal laminz were originally
separated from the body of the vertebre, but were afterwards united
to it. In the bodies of the smaller vertebree the epiphyses are
wanting, and Mr. Owen agrees with Dr. Harlan in inferring from the
common occurrence of tliis condition, that there were originally
three separate points of ossification in the body of the vertebre; a
character never noticed in the vertebre of Saurians, but a most pro-
minent one in those of the Cetacea. Another argument in favour
of the mammiferous and cetaceous nature of the Basilosaurus is de-
duced from the great capacity of the canal for the spinal chord,
which in the Cetacea is surrounded by an unusually thick plexiform
stratum of both arteries and veins. The cetaceous character is
further manifested in the short antero-posterior extent of the neura-
pophyses as compared with that of the body of the vertebra; in
their regular concave posterior margin, and the development of the
articular apophyses only from their anterior part: also in the form
and position of the transverse processes, which however present a
greater vertical thickness than in the true Cetacea, and approach in
this respect to the vertebra of the Dugong.

With respect to the other bones of the. Basilosaurus, Mr. Owen
stated, that the ribs in their excentric laminated structure are pecu-
liar, and unlike those of any Mammal or Saurian. The hollow
structure of the lower jaw of the Basilosaurus, which has been ad-
vanced as a proof of its saurian nature, Mr. Owen showed occurs
also in the lower jaw of the Cachalot, and is therefore equally good
for the cetaceous character of the fossil.

In the compressed shaft of the humerus, and its proportion to the
vertebra, the Basilosaurus again approximates to the true Cetacea,
as much as it recedes from the Enaliosaurians; but in the expansion
of the distal extremity and the form of the articular surface, this hu-
merus stands alone; and no one can contemplate the comparative
feebleness of this, the principal bone of the anterior extremity, with-
out agreeing with Dr. Harlan, that the tail must have been the main
organ of locomotion.

Mr. Owen, in compliance with the suggestion of Dr. Harlan, who,
haying compared with Mr. Owen the microscopic structure of the

Geological Society. 307

teeth of the Basilosaurus with those of the Dugong and other ani-

mals, admits the correctness of the inferences of its mammiferous

nature, proposes to substitute for the name of Basilosaurus that of

Zeuglodon, suggested by the form of the posterior molars, which re-

semble two teeth tied or yoked together.

A notice on ‘“‘ the Occurrence of Graptolites in the Slate of Gal-
loway in Scotland,” by C. Lyell, Esq., V.P.G.S., was first read.

On examining some specimens of slaty sandstone and shale, col-
lected by Mr. John Carrick Moore, on the shore of Loch Ryan in
Galloway, Mr. Lyell discovered distinct remains of Graptolites, re-
sembling those found in the Silurian strataof England and Sweden.
As Mr. Lyell is not aware of these zoophytes having been before
observed in Scotland, and as organic remains are exceedingly rare
in the great range of slaty sandstone and shale which extends from
St. Abb’s Head to Galloway, he considers the discovery of a fossil,
affording a test of the relative age of those beds, not unimportant.
The strata containing the Graptolites are nearly vertical, and their
strike is west-south-west and east-north-east.

Mr. Sharpe’s paper ‘‘ On the Geology of the Neighbourhood of
Lisbon,” commenced at the meeting held on the 9th of January, was
then concluded.

In 1832, Mr. Sharpe laid before the Society, a short account of
the geological structure of the neighbourhood of Lisbon* ; but having
since that period resided for a considerable time in the same district,
he gave in the paper read on the 23rd instant, the result of his more
extended and matured acquaintance with the country.

The tract described by Mr. Sharpe, is bounded towards the north
by a line extending from Torres Vedras by Sobral to Villa Franca,
and in the south by the coast from Cape Espichel to St. Ubes; and
the whole of its area is about 650 square miles.

The formations are arranged by the author in the following order,
the iocal names having been taken from the points where the strata
are best exhibited :

Tertiary. (a.) Upper tertiary sand.—(b.) Almada beds.-—(c.) Lower
tertiary conglomerate.

Secondary. (d.) Hippurite limestone.—(e.) Red sandstone.—(f.)
Espichel limestone.—(g.) Slate clay and shale-—(h.) San
Pedro limestone.—(z.) Older red conglomerate.

Igneous Rocks.—Basalt.—Granite.

TERTIARY FORMATIONS.

The tertiary deposits occupy a tract, only a portion of which is
included within Mr. Sharpe’s district, as they extend in a north-east
direction to Abrantes, a distance of eighty miles, and in a south-east to
Alcacer do Sal, a distance of fifty miles. The Tagus flows through
the tract from Abrantes to the sea, but the greater part of the ter-
tiary strata are situated to the south of the river.

(a.) Upper Tertiary Sand.—This formation consists of about 100
feet of fine gray quartzose sand, and 150 feet of coarse quartzose
ferruginous sand and gravel. It constitutes nearly the whole of the
* Proceedings, vol. i. p. 394. [or et E. Phil. Mag., vol. i. p. 227.—Ep.]

9

“

$08 Geological Society.

tertiary district, south of the Tagus, included within the author's sur-
vey. The strata are usually quite horizontal, except at the edges of
the basin, where they rest upon the inclined beds of the subjacent
deposits; and the author did not observe any instance of their
having been disturbed. They generally repose upon the Almada
limestone, but near Aldea do Meco, to the north of Cape Espichel,
they are in contact with the red sandstone formation. No traces of
organic remains have been noticed in any. part of these sands. In
the lower beds a mine of quicksilver was worked profitably during
the last century near Coina, south of tne Tagus; and the gold dust
for which the sands of that river have been so long celebrated, Mr.
Sharpe believes, is derived also from the lower or ferruginous sands.
(6.) Almada Beds.—A complete section of this deposit is not ex-
hibited in the neighbourhood of Lisbon, and the strata are so very
irregular both in thickness and composition, that it is difficult to
connect the sections displayed at different localities. The strata are
best exposed in the cliff south of the Tagus, between Trafaria and
Almada. The whole of the series is arranged by Mr. Sharpe in
three groups, the uppermost consisting of limestone and sands, the
middle of blue clay, and the lowest of another series of limestones
and sands: but Mr. Sharpe does not attach much value to the sub-
division ; as the same fossils are found in the beds above and below
the blue clay. ‘The deposit constitutes a triangular tract on the
Lisbon side of the ‘T'agus, extending from that city to Verdelha, a di-
stance of about fourteen miles ; it also caps some hills between Belem
and Fort St. Julian. South of the Tagus, it forms the cliffs already
mentioned; and a band which ranges from St. Ubes northwards to
Palmella, and thence south-west to within a mile of Aldea do Meco,
skirting the flanks of a ridge of secondary formations. A detached
mass of the Almada beds occurs at the western end of the Serra de
San Luiz, between St. Ubes and Azeitao, abutting unconformably
against the elevated edges of the beds of red sandstone, and another is
on the shore at the foot of San Felippa near St. Ubes. North of the
Tagus, the beds incline from 5° to 10° to the south-east; but to the
south of the river between St. Ubes and Aldea do Meco, the dip varies
from 25° to 80°, and conforms to the position of the band with respect
to the ridge of secondary rocks, being to the south-east between St.
Ubes and Palmella, andto the north-west between the latter town and
Azeitao. The beds of the detached mass near the western end of the Serra
de San Luiz, dip about 30° north, and those of the mass on the shore
at the foot of San Felippa, 80° towards the older red conglomerate,
having been thrown over beyond the perpendicular. On the coast
at Casilhas near Almada, the level of the strata is affected very con-
siderably by faults. North of the Tagus a fault cuts off the tertiary
strata at Oeiras, the Almada beds forming one bank of the stream,
and the Hippurite limestone the opposite; but the strata of each
deposit are horizontal. In Lisbon the Almada beds rest uncon-
formably on the Hippurite limestone ; but between the city and Ver-
delha, conformably on the lower tertiary conglomerate. In the band
ranging from St. Ubes by Palmella-towards Aldea do Meco, they

tie

Geological Society. 309

‘repose in general also conformably on the red sandstone. The

greatest height attained by the formation is the Castle Hill near Pal-
mella, the summit of which is 930 feet above the level of the sea,
and at this point two lines of disturbance meet. Fossils are very
abundant in some of the beds, but sufficient attention has not yet
been paid to them to permit their being compared with the organic
remains of other tertiary districts. A long-hinged oyster, Ostrea
longirostris, Mr. Sharpe considers identical with a species common
in the tertiary deposits of the south of Spain. Small quantities of
quicksilver have been found in several places in a bed of sand im-
mediately above the blue clay or central division of the formation.

(c.) Lower Tertiary Conglomerate-—This deposit consists in the
upper part of distinctly stratified conglomerates, composed of lime-
stone pebbles imbedded in a calcareous matrix; and in the lower
of sands, grits, gravel, and marl. Within the district examined by
Mr. Sharpe, it occurs only on the Lisbon side of the Tagus, forming
a band from that city by Odivellas, Camarate, Loures, and Tojal,
to the neighbourhood of Alhandra, on the banks of the Tagus, and
skirting the western and north-western boundary of the Almada
beds. ‘The conglomerate occurs also on some of the detached hills
between Belem and the Bay of Cascaes. The deposit dips to the
south-east under the Almada beds at an angle of 10° or 15°, but in
the lowest strata the dip is 30°. For a short distance south of
Alhandra, the conglomerate rests upon the red sandstone, but
throughout the remainder of its range upon basalt. No organic
remains were noticed in the deposit.

SECONDARY FORMATIONS.

In few countries can the separation between the tertiary and
secondary formations be more strongly marked than in the neigh-
bourhood of Lisbon. The deposits of the older class of rocks, Mr.
Sharpe states, were disturbed and denuded previously to the com-
mencement of the tertiary epoch, and an immense mass of basalt is
interposed between the newest of the secondary rocks and the most
ancient of the tertiary series.

(d.) Hippurite Limestone.—The upper part of this formation con-
sists of alternations of marl and limestone, succeeded by beds of
limestone containing thin horizontal beds of flint; and the lowest
part of various strata of compact limestone ; amounting in the whole
to a thickness of above 500 feet. The formation is confined to the
north of the Tagus, where it presents several distinct bands, which
rest upon the red sandstone, and are overlaid by basalt. The most
southern tract extends from Cascaes Bay nearly to Loures; another
irregular strip ranges from Montelavar to a little to the eastward of
Bucellas; and a third district, commencing near Villa Franca,
stretches to the north beyond the range of Mr. Sharpe’s district. A
portion of Lisbon also stands upon Hippurite limestone. In some
parts, especially on the coast, the dip is slightly towards the
south-east, but from Loures to beyond Bellas it varies from 30°
to 50° in the same direction. The strata do not always rest con-
formably on those of the subsequent red sandstone, for near Cas-
caes, the limestone beds are horizontal, and the sandstone on which

310 ’ Geological Society.

they lie is inclined at a considerable angle. The narrow valley of
Alcantara, close to Lisbon, is the line of a considerable fault, the
strata dipping in opposite directions from the valley, or 15° towards
the west, and 10° towards the east. Another anteclinal line inter-
sects the upper part of this valley ; and at the point where the two
disturbances cross, considerable derangement of the strata is produced.
In one quarry Mr. Sharpe noticed eight small faults, and the walls
of the rocks on each side of the fissures had a beautiful polish.
Though the author has adopted the term Hippurite limestone for
this deposit, yet he did not discover any remains of that genus, but
great abundance of Spherulites, some of them probably of known
species, and other fossils of the family of Rudista. He obtained
also a considerable number of shells, including Ezogyra flabellata,
Pecten quadricostatus and Pecten striato-costatus.

(e.) Red Sandstone.—This formation consists of various sands,
sandstones, marls, and limestone, which are grouped by Mr. Sharpe
in the following manner:

Upper Division.—Ferruginous sands, sandstones, and coloured
marls.

Middle Division.—Calcareous sandstones and coarse limestones.

Lowest Division.—Coarse sands, sandstones, and grits.

The extent of country, composed of this formation, is very con-
siderable. North of the Tagus, the red sandstone covers the greater
portion of the area to the westward of the tertiary strata and Hip-
purite limestone, the only tract belonging to other deposits being
the hills at Cintra, and the lower ridges immediately surrounding
them. A denuded strip of sandstone is also exposed between Loures
and Cape Sinchette. South of the Tagus, the red sandstone forms
a tract of variable breadth, extending from Palmella to the coast, a
little north of Cape Espichel. The beds of this formation are greatly
affected by faults and vary much in the angle of inclination, but the
prevailing dip is towards the south-east throughout the districts on
the Lisbon side of the Tagus. In the tract between Palmella and
the coast, the strata have also been disturbed by considerable faults,
but their usual dip is north, or north-west, at a high angle. Near
Lisbon, the connexion of the red sandstone with the subjacent for-
mations is not often exposed. North of Cintra the sandstone rests
almost horizontally upon inclined strata of Espichel limestone,
shale, San Pedro limestone and granite. South of the Cintra hills,
it reposes very irregularly upon the Espichel limestone: and south
of the Tagus, with every degree of want of conformity, upon the
limestone of the Serra d’Arrabida (Espichel limestone); and in a
great variety of positions upon the lofty peaks of the older red con-
glomerate of the Cavoens and the Serra de San Luiz near St. Ubes.
Lignite occurs in several places, and in sufficient quantities to have
led to unsuccessful researches for coal. Sulphur also thickly en-
crusts some of the sandstone strata; and gypsum has been worked
near Santa Anna, south of the Tagus. Mr. Sharpe is of opinion,
that the tepid springs of Estoril, near Cascaes, may derive their virtues
from the sulphureous strata; and that the hot springs of Caldas
da Rainha may owe their sulphureous qualities to similar strata.

Geolog ical Socrety. 311

The only organic remains found in the sandstones, are vegetable
impressions and seed-vessels ; but in the calcareous beds, corals and
shells occur, and Mr. Sharpe has been able to identify some of the
latter with the Perna rugosa, Trigonia literata and Terebratula in-
termedia, of the English secondary oolitic series.

(f.) Espichel Limestone.—This formation constitutes the flat, outer
band which encircles the Cintra hills, also the range of hills be-
tween Cape Espichel and Cezimbra, and most probably the Serra
d’ Arrabida near St. Ubes. At the first of these localities, it consists
of thick beds of gray coarse limestone, alternating with thinner ones
of shale or marl; at the second, of a similar limestone with fewer
layers of shale; and at the Serra d’Arrabida, of compact gray lime-
stone with no partings of shale, except towards the bottom of the
formation. Around the hills of Cintra, the strata dip as from a
centre, at angles varying from 20° to 75°; between Cape Espichel
and Cezimbra their inclination is from 45° to 70° to the north; and
in the Serra d’ Arrabida the prevailing dip is also to the north at a high
angle, but at the west end of the Serra it varies from north to north-
west and north-east; whilst in the northern side of the Serra de
Vizo, or the eastern prolongation of the Serra d’Arrabida, the dip
is toward the south. In the Cintra district the limestone rests con-
formably on the subjacent formation of shale ; between Cape Espi-
chel and Cezimbra, and in the Serra d’Arrabida the bottom beds
are not exposed, and consequently the connexion withthe inferior de-
posits is not visible ; but in the Serra de Vizo the limestone reposes
quite unconformably upon highly inclined strata of the older red con-
glomerate. The organic remains of this formation are principally
casts of shells,which are not easily separable from the matrix. One of
the specimens obtained by Mr. Sharpe closely resembles a Trigonia
from the green sand of Blackdown.

(g.) Shale-—The upper portion of this deposit consists princi-
pally of shale, varying a good deal in character; the middle of
indurated shale alternating regularly and conformably with beds
of trap from five to twenty feet thick, and the lowest of dark shale.
Near Ramalhao, where the formation is best displayed, there are
from twenty to thirty distinct alternations of igneous rocks and shale,
the latter being altered and indurated ; but in the cliff at the Praia de
Adraga, where the deposit is diminished to about 200 feet, there is
only one bed of igneous origin. The formation rests with perfect
conformity on the San Pedro limestone, dipping on all sides from the
central granite axis of Cintra, at angles from 30° to 60°.

(h.) The San Pedro Limestone forms an inner zone around the
Cintra hills, resting upon the granite. The upper beds are dark
gray and earthy; but as the limestone approaches the granite,
it gradually passes into a crystalline marble. At the village of
San Pedro the following series is exposed :—

Dark gray compact limestone several hundred feet

thick.
Gray limestone with very slight traces of crystalline

texture, and towards the bottom granular...... 200 feet
Coarse crystalline marble, white or gray and white 100

312 Geological Society.

Coarser crystalline marble, usually gray, but towards
the bottom bluish white, andstill coarser ...... 100 feet.

Granite.

The same gradual change may be traced all around the Cintra
hills, wherever the limestone can be seen resting upon or approach-
ing the granite. The lines of stratification are scarcely affected by
the change in the structure of the stone, and the dip is from the
granite at angles between 40° and 70°. Imperfect casts of a
bivalve and an univalve were found in this limestone by the author.

(i.) Older Red Conglomerate.—This formation occurs only west
of St. Ubes; and though Mr. Sharpe describes it the last of the
sedimentary series, yet he is not certain respecting its relative geolo-
gical antiquity. Near St. Ubes it rises from beneath the red sand-
stone and the Espichel limestone, and it is therefore older than
either of those rocks. The conglomerate consists of rounded peb-
bles of white or ferruginous quartz, with a few of jasper, mica slate,
and limestone. They vary from half an inch to more than a foot in
diameter, and are firmly embedded in a coarse ferruginous sandstone.
The highest ridge of the Serra de Covoens consists of this forma-
tion, also the eastern end of the Serra de San Luiz, the higher
parts of the Serra de Vigo, and the coast from St. Ubes to the foot
of the Serra d’ Arrabida. At the eastern end of the Serra de Co-
voens and in the Serra de San Luiz, the dip of the beds is to the
north, at angles varying from 0° to 50°; at the eastern end of the
Serra de Vigo they incline about 30° to the south; more to the west-
ward, in the same serra, they are in some places vertical. in others
they dip about 50° to the north; and at the Torre de Outao, at the
foot of the Serra d’ Arrabida, they are inclined about 70° north-east.

The description cf the sedimentary rocks is followed by an
attempt to compare each formation with its probable equivalent in
other parts of Europe; but as the Lisbon fossils have not yet been
examined with sufficient care, Mr. Sharpe does not venture to draw
any positive conclusions.

Of the tertiary series, the Almada beds alone offer any terms of
comparison, and these are not very satisfactory. The fossils col-
lected by the author are said to differ from those of the London
clay, with the exception of one species, which is considered iden-
tical with Natica similis ; but a long-hinged oyster, Ostrea longi-
rostris, abundant in the Almada beds, agrees with a fossil common
in the tertiary strata of Baza, Lorca and Alhama, in the south
of Spain, described by Brigadier Silvertop; and Mr. Sharpe from an
examination of these deposits, as well as from the agreement in the
oyster, is induced to consider the Murcia and the Lisbon series as
of the same age.

The Hippurite limestone, Mr. Sharpe has no doubt, is the equiva-
lent of the extensive formation in the south of Europe characterized
by the abundance of remains belonging to the family of Rudista,
and considered the representative of the chalk and greensand series
of England and the north of France.

The red sandstone Mr. Sharpe considers to belong also to the
secondary system, in consequence of his having obtained from it

Geological Society. 313

specimens of Terebratula intermedia, Perna rugosa, and Trigonia
literata.

Of the formations below the red sandstone, the author offers no
data for establishing a comparison with deposits in other parts of
Europe further than that the Espichel and Arrabida limestones may
be of the same age as the limestone of the rock of Gibraltar, and
that the shale near Cintra may be the equivalent of the shale which
underlies the Gibraltar limestone, and constitutes a considerable
portion of Andalusia. He is also of opinion, that the Cintra shale
is of the same age with the immense deposit of similar composition,
which covers the centre of the province of Alentejo, extending from
Aleacer do Sol to the confines of Algarve.

The older red conglomerate of the neighbourhood of St. Ubes,
Mr. Sharpe considers as probably identical with the conglomerate
largely developed on the banks of the Vonga, and which rests
upon mica slate a little to the south of Oporto.

IGNEOUS ROCKS,

Basalt.—The principal deposit of this rock forms one of the most
important features in the geology of the district to the north and west
of Lisbon, occupying an irregular area, estimated to be not less than
eighty square miles. It is difficult to define its limits without reference
to an accurate map; but it may be stated to form a tract of very
varying breadth, from the shore west of Belem by Queluz, and
Odivellas to Loures. In the neighbourhood of the last village, it
turns $.W. and N.E., ranging in the former direction to the
neighbourhood of Montelavar, and in the latter nearly to Verdelha
on the banks of the Tagus. Besides this immense continuous mass,
many of the hills north of Oeiras, near the mouth of the Tagus, are
capped by basalt, evidently outlying patches, once connected with
the great deposit. Basalt also forms the summit of the hills near
Sobral and St. Sebastiano, resting upon the red sandstone. It has
been already stated, that beds of trap alternate regularly and with-
out any appearance of disturbance with the central division of the
shale formation near Cintra.

The rock varies considerably in character, and is occasionally
columnar. It is stated to have frequently the appearance of a black
indurated clay with an irregular schistose cleavage, and breaking
into very irregular rhombs.

The only beds which rest upon the basalt belong to the tertiary
series, but it overlies both the Hippurite limestone and the
red sandstone. ‘Io the westward of Loures, it cuts through these
formations; and the red sandstone, to the south of the line of
intersection, has been brought to a level with the Hippurite lime-
stone to the north of the line. The strata of Hippurite limestone
to the north are nearly horizontal, while those of the red sandstone,
and limestone to the south, are highly inclined. Hence Mr. Sharpe
infers that the great mass of basalt was poured forth from fissures
in the neighbourhood of Loures.

The cliffs in the bay of Cascaes exhibit fine sections of basaltic
dykes and disturbances; and on the beach west of Cezimbra masses
of basalt are intruded into strata of red sandstone, which exhibit

314 Astronomical Society.

great marks of disturbance. The Espichel limestone and the red
sandstone have been also greatly elevated at the Castle Hill at Ce-
zimbra, by a trap rock of which the date is uncertain.

Although the author had innumerable opportunities of observing
the junction of the basalt with the beds below it, yet in no instance
did he observe any change in the characters of the subjacent rocks.
The alteration produced in the beds of shale, which alternate with
trap rocks near Cintra, has been already noticed. Mr. Sharpe con-
siders these igneous strata to have been ejected contemporaneously
with the deposition of the shale, and to be consequently older than
the great coating of basalt. The Espichel limestone, in contact
with the trap near Cezimbra, is also altered, being of a crystalline
texture to a distance of fifty feet from the igneous rock.

Granite is found only in the neighbourhood of Cintra, forming a
range of hills about seven miles in length and five in breadth. Their
greatest altitude is less than 2000 feet. The prevailing rock is a
true granite consisting of nearly equal proportions of quartz
and felspar with a little mica; but towards the western end of the
chain, syenite and porphyry occur. In the central portions of the
hills, the granite is coarsely grained, and splits into large irregular
blocks; but on the flanks it is schistose, finely grained, cleaves
into rhombs, and might be mistaken for a sandstone. Veins of
large-grained granite, however, occur in the schistose variety, and
veins of finely-grained in the coarse central masses.

Mr. Sharpe then describes, in detail, the dislocations in the sedi-
mentary strata on the flanks of the granitic hills; and he shows that
all the formations, from the San Pedro limestone to the Espichel,
have been dislocated, and thrown into highly inclined positions, but
the details cannot be clearly understood without the aid of sections.
It may however be stated, that in consequence of the red sandstone
resting in nearly horizontal strata against the inclined beds of the
lower formation, the latter was disturbed previously to the de-
position of the sandstone, and that consequently the irruption of
the granite of Cintra took place at a period anterior to the origin of
the sandstone.

Mr. Sharpe describes also with considerable minuteness the dis-
turbance near Palmella, south of the Tagus; and he infers, from the
relative position of the strata, that there have been, in that district,
considerable elevations at four distinct periods.

The paper concludes with some observations on the earthquake
of 1755; and the author, shows, that its effects were entirely
confined to the tertiary strata, and were most violently felt on the
blue clay belonging to the Almada beds, on which the lower part
of the city is constructed. Not a building on the Hippurite lime-
stone, or the basalt, was injured.

ASTRONOMICAL SOCIETY.
Jan. 11, 1839.—The following communications were read: “ On
the Obliquity of the Ecliptic.” By the Rev. Dr. Pearson.
The object of this paper is to give an account of a determination
of the annual diminution of the obliquity, by a comparison of obser-

Astronomical Society. $15

vations of the solstices made by Dr. Pearson at South Kilworth,
with similar observations of Bradley at the Royal Observatory. Dr.
Pearson remarks, that the most remote determination of the obli-
quity which has any claim to precision, is Dr. Bradley’s; and, ac-
cordingly, some one of his obliquities has been chosen by almost all
practical astronomers for the purpose of comparison with their own,
in order to determine the annual diminution. But, notwithstanding
the apparent facility with which the diminution may be obtained, by
a comparison of determinations separated by a considerable interval
of time, no two astronomers agree in their results. Dr. Maskelyne
considered it to be —0!'"52; Delambre adopted —0'"48; Dr. Brink-
ley, —0'''43; and Bessel, —0!"457. These discrepancies, which
in the course of years amount to considerable quantities, demand
that the question of preference should be settled ; and this can only
be effected by practical methods.

Bradley determined his summer and winter obliquities by separate
deductions,—a method which rendered the result dependent on the
assumed latitude of the place. He assumed the latitude of the ob-
servatory to be 51° 28’ 40", which has since been shown to be too
great by at least one, if not two, seconds; and, accordingly, all his
obliquities are affected with a corresponding error, which may ex-
plain the reason why the Greenwich winter obliquities are smaller
by some seconds than the summer ones. But it is easy to see that,
by combining the observations of two successive solstices, the lati-
tude may be eliminated; for, half the difference of the sun’s extreme
meridian altitudes gives the obliquity due to the middle of the in-
terval, which, if the winter solstice be taken first, will be the vernal
equinox. In like manner, if we take three, or any odd number of
successive obliquities, separately deduced by means of an assumed
colatitude, the sum of the whole, divided by their number, will give
the mean obliquity belonging to the middle epoch, independent of
the assumed colatitude.

Bradley’s first recorded determination of an obliquity was in the
winter of 1753; and he observed seven winter solstices, and as many
summer ones, without interruption. Omitting the first determina-
tion, in order to have an odd number, and taking the thirteenth
part of the sum of the remaining thirteen half-yearly determinations,
we have an average obliquity corresponding to June 1757, viz.
23° 28' 13/4446.

Dr. Pearson commenced his solstitial observations in June 1828,
and continued them till June 1838, thereby obtaining twenty-one
successive half-yearly obliquities, the sum of which gives an average
obliquity corresponding to June 1833. His result is 23° 27! 392409,
and is therefore less than the average resulting from Bradley’s de-
terminations by 34'"2037. Dividing this difference by 76, the num-
ber of years between the two epochs (1757 —1883), the annual di-
minution is found = —0'"4500. This accords very nearly with
the annual diminution adopted by Bessel in the Tabule Regio-
Taontanee.

The instrument with which the observations were made, is an al-

316 Astronomical Society.

titude and azimuth instrument, described circumstantially in vol. ii:
part i. of the Memoirs. Dr. Pearson describes the mode in which
the instrument was used and its errors corrected, together with the
methods followed in reducing the observations, and the elements
employed in computing the corrections for parallax, refraction, nu-
tation, and the sun’s latitude; and concludes with a synopsis of the
reduced observations, which were in number 1648, and a table of
the mean obliquity on the lst of January in each year, from 1750 to
1900, both inclusive, deduced from the above determination of the
annual diminution.

«© On the Parallax of a Centauri.” By Professor Henderson.

The two stars designated a! and a? Centauri, are situated within
19" of space of each other. On comparing the observations of La-
caille with those of the present time, it has been found that, although
the two stars have not sensibly changed their relative positions, each
has an annual proper motion of 3°6 seconds of space. It thus ap-
pears that they form a binary system, having one of the greatest
proper motions that have been observed; and from this circumstance,
and the brightness of the stars, it is reasonable to suppose that their
parallax may be sufficiently sensible to powerful instruments.

On reducing the declinations from his observations at the Cape of
Good Hope, Mr. Henderson remarks, that a sensible parallax ap-
peared, but he delayed communicating the result until it should be
seen whether it was confirmed by the observations of right ascen-
sion made by Lieutenant Meadows with the transit instrument.
He now finds that these observations also indicate a sensible pa-
rallax.

It is to be observed, that the observations both of right ascension
and of declination were not made for the purpose of ascertaining the
parallax, but of determining the mean places of the stars with a pro-
per degree of accuracy. Had the author been aware of the proper
motion at an earlier period, a much greater number of observations,
and of such as would have been better adapted for ascertaining the
parallax, would have been made, and the result thereby rendered
more secure.

The right ascensions and declinations of the two stars (which are
always above the horizon of the Cape, and favourably placed for ob-
servation at all seasons,) have been determined by comparisons with
such of the principal or standard stars as were observed on the same
day. It is consequently assumed that the latter have no sensible
parallax. ‘The mean places of the standard stars, or rather their
relative positions, are also assumed to be known; and, in reducing
the observations to the beginning of 1833, the coefficient of aberra-
tion has been assumed =20"''5, and that of lunar nutation =9!-25.
Recent observations make the coefficient of aberration less; but a
term is introduced into the equations of condition, by which the
effect of a change in the aberration is immediately obtained.

For the determination of the parallaxes, three systems of equa-
tions of condition are formed for each star, namely, from the ob-
servations of right ascension, the direct observations of declination,

Intelligence and Miscellaneous Articles. 317

and the reflected observations of declination. On resolving the
equations by the method of least squares, and assuming the coefti-
cient of aberration to be 207-36, Mr. Henderson finds the following
results :
Parallax of a! Centauri =

+0” 92; probable error 0°35 ; from observations of right ascension.

+1 +42; probable error 0 ‘19; from direct observations of declination.

+1 -96; probable error 0 -47; from reflected observations of declination.

And = + 1-38, with a probable error of 0-16, by taking a mean of the three

determinations according to their weight.
Parallax of a? Centauri =
+048 ; probable error 0/34 ; from observations of right ascension.
+1 -05; probable error 0 ‘18; from direct observations of declination.
+1 °21; probable error 0 -64; from reflected observations of declination.

And = + 0-94, with a probable error of 0/16, by taking the mean according
to their weights.

If we suppose that the two stars are at the same distance, then
the parallax = + 1°16, with a problem error of 0-11. It there-
fore appears probable, that these stars have a sensible parallax of
about one second of space.

XLIX. Intelligence and Miscellaneous Articles,

POSTSCRIPT TO THE COMMUNICATION OF PROF. SEDGWICK AND
MR. MURCHISON IN THE PRESENT NUMBER AT P. 24].

WE: alluded to the possibility of the Devonian or Old Red Sy-
stem being much developed in Ireland, and under mineral
characters analogous to those of Devon. In support of this view, we
may add, that since this paper was printed, Mr. Charles W. Hamil-
ton has called our attention to a paper read by him before the Geo-
logical Society of Dublin, in 1837, in which he described the rock
hitherto called grauwacke slate, which occupies a great extent in
the county of Cork, as lying conformably upon the old red sandstone
and conglomerate of the Gaulty Mountains and the Reeks in Kerry,
and supporting the carboniferous limestone into which it gradually
passes,

This red conglomerate rests unconformably upon a great thickness
of older slates and conglomerates, which Mr. Hamilton has described
as exactly similar to those which are exposed in a section made from
Mr. Pennant’s quarries in Caernarvonshire to Ogwen. Ina paper
read before the Geological Society of Dublin last month, Mr. Hamil-
ton has also stated his belief, that slates occupying a large space
between the Mourne and Dublin Mountains, are equivalent to those
in the immediate neighbourhood of Cork, and may therefore be re-
ferred to the old red sandstone.

MR. CROSLEY’S PNEUMATIC TELEGRAPH.

In inserting the account of Mr. Crosley’s pneumatic telegraph in
our last number, we had not space for some of the details, which we
therefore now give in continuation.

In establishments where the telegraphic communications do not
require the constant attendance of a person to observe them, and

318 Intelligence and Miscellaneous Articles.

where periodical attendance is sufficient, the signals may be cor-
rectly registered on paper, by connecting with the air-tube an in-
strument called a pressure register, invented by the projector of
the pneumatic telegraph, which has been successfully employed in
large gas-light establishments upwards of fourteen years, for regi-
stering the variations of the pressure of gas in street mains. The
same instrument produces also an increased range of the index scale,
by which means the chance of errors from minute divisions is obviated.

It may be observed, that the introduction of railways has not
only created an additional use for telegraphic communications, but
the important difficulty which previously existed in the expense of
providing a proper line and safe foundation is, at once, removed by
the site of the railway itself, possessing as it does, by its police, the
most ample security against injury, either tothe tubes or electric wires.

There being now three different projects for improvements in tele-
graphic communications, viz. the electro-magnetic, the hydraulic,
and the pneumatic telegraph,—and assuming that such improve-
ments are of importance to the state, as well as to railway proprie-
tors and the community at large, it seems desirable that their merits
should be thoroughly investigated by competent engineers, and that
the joint aid of Government should be solicited, in conjunction with
that of railway proprietors, for the purpose of establishing, on a
practical scale, the most eligible project.

The prominent questions for consideration seem to be—the cer-
tainty and accuracy of the communications, the first cost, the ex-
pense of repair and superintendence, also the time required for trans-
mitting intelligence.

On the question of time, it is quite clear that neither the hydrau-
lic nor the pneumatic can compete with the electro-magnetic tele-
graph in rapidity. No doubt, on investigation, each project will be
found to possess its peculiar advantages. ‘Thus, im considering the
advantage one may have in point of time, another may possess a
greater degree of certainty or accuracy in the communications, suf-
ficient to outweigh the difference of time, for instance, between 1
second and 1 minute, or even between 1 second and 5 or 10 minutes.

The time occupied in transmitting intelligence by the pneumatic
telegraph will depend on the capacity of the air-tube, the degree of
compression given, and the distance between the stations ; but should
greater dispatch be required than is afforded by one tube, and the
cost be of minor importance, several tubes may be employed, each
fitted in the manner above described, so that all the figures con-
tained in one telegraphic number, may be communicated at once
with four tubes. Nine thousand nine hundred and ninety-nine dif-
ferent signal numbers may be communicated, referring to so many
words or sentences, and these numbers may be multiplied fourfold
by letters A, B, C, &c., as indices to distinguish each series.

The projector of the pneumatic telegraph is not in possession of
any results of experiments on a practical scale by the electro-mag-
netic or by the hydraulic telegraph, employed at any considerably
extended distances, or of their continued operation for any long
period of time; nor can he offer much decisive information, of a

Meteorological Observations. 819

practical nature, analogous to the operation of the pneumatic tele-
graph on these points; the following circumstances may, however,
be referred to:

There has been upwards of twenty years’ experience in the trans-
mission of gas for illumination through conduit pipes of various di-
mensions. In several instances, the gas has been supplied at the
distances of from five to eight miles by low degrees of pressure. As
one proof of great rapidity of motion, it has been observed, that when
any sudden interruption in the supply has occurred at the works,
the extinction of all the lights, over large districts, has been nearly
simultaneous. Another instance of the great susceptibility of mo-
tion which frequently happens, is the flickering motion of the lights
at great distances when water has accumulated in the pipes.

The only experience in the transmission of atmospheric air through
conduit tubes, which applies more particularly to this question, may
be referred to at three railway establishments; viz. Edinburgh,
Liverpool, and Euston-square, London. In these establishments,
air-tubes, from 14 to 2 miles in length, have been employed for the
purpose of giving notice when a train of carriages is ready to be
drawn up the inclined plane by the stationary engine at the summit,
so that it may without delay be putin motion. ‘This notice is com-
municated by blowing a current of air through the tube at the foot
of the inclined plane, and sounding an organ-pipe, a whistle, or an
alarm-bell at the stationary engine. It will be satisfactory to know,
that this operation has been regularly performed from two to four
years without one single failure or disappointment.

METEOROLOGICAL OBSERVATIONS FOR FEBRUARY, 1839.

Chiswick.—Feb. 1. Overcast: fine: frosty at night. 2. Sharp frost. 8.
Thawing: hazy. 4. Fine: cloudy. 5. Hazy: heavy rainat night. 6. Foggy.
7. Drizzly. 8. Hazy: cloudy and windy at night. 9. Overcast. 10. Very
fine. 1]. Dense fog, 12. Fine: overcast: rain. 13. Fine. 14. Boisterous.
15. Clear. 16. Stormy and wet: fine. 17. Clear. 18. Snowing: sleet :
clear. 19. Sharp frost. 20. Bleak and cold. 21. Cloudy and cold: dry haze :
rain at night. 22. Hazy: rain, 23. Rain: very fine. 24. Very fine. 25.
Clear: showery: fine. 26. Clear and frosty: fine. 27. Fine. 28. Very fine.

Boston.— Feb. 1. Fine. 2. Cloudy. 3. Cloudy: rain early a.m. 4, 5. Fine:
raine.m. 6. Cloudy. 7,8. Fine. 9. Fine: rainr.m. 10, Fine. 11.
Cloudy. 12,13. Fine. 14. Stormy. 15. Fine. 16. Cloudy: rain early a.m.
17—19. Fine. 20,21. Cloudy. 22. Cloudy: snow early a.m. 23. Cloudy:
rainearlya.m. 24, Fine. 25. Fine: hailandsnowr.m. 26. Fine. 27.
Cloudy. 28. Fine.

Applegarth Manse, Dumfries-shire.—Feb. 1. Clear day: ground covered with
snow. 2. Cloudy: gentle thaw. 3. Moderate thaw: snow melting slowly.
4. Moderate thaw: small rain evening. 5. Thaw continuing: snow melting.
6. The same: very temperate: rain p.m. 7. Stormy day: snow gone: very wet.
8. Quiet a.m.: wind rose p.m.: wet. 9. Rain: dark and cloudy: mild. 10.
Fair and mild: threatening p.m. 11. Rawcold: cloudy. 12. Fine day: flying
hail showers. 13. Mild a.m.: rain and wind p.m. 14. Boisterous day: fre-
quent hail and sleet. 15. Tolerable spring day: wet p.m. 16. Showers of
snow: high wind. 17. Snow half an inch deep: frosty. 18. Moderate day :
snow melting: freezing. 19, Fine frosty day : getting cloudy p.m. 20. Favour-
ableday: slight snow. 21. Hard frost: cloudy: slight snow rm. 22, Thaw:
snow preceding night: snow melts. 23. Very fine day: temperate and spring-
like. 24, On the whole mild; occasional showers. 25. Moderately temperate :
slight frost a.st, 26. Fine day though rather chill, 27. Severe showers of sleet :
cleared up v.a, 28. Occasional slight showers.

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THE

LONDON anp EDINBURGH
PHILOSOPHICAL MAGAZINE

AND
JOURNAL OF SCIENCE,

SS

[THIRD SERIES.]

MAY 1839.

L. Researches in the Undulatory Theory of Light, continued;
on the Elliptical Polarization produced by Quartz. Part II.
By J. Tovey, Esq.

To the Editors of the Philosophical Magazine and Journal.

GENTLEMEN,
the former part of this investigation (present volume,
p- 172) the terms involving A;, A’;, were supposed to be
insensible; but the comparison of the results of the calcula-
tion with the observed phenomena, by which every supposi-
tion ought to be verified, affords no proof of this; for if we
restore the neglected terms, by adding respectively, to the
4 x? , bn?
AP 3 —A 3 a 3 and (26.)

expressions (21.), — A,

half the same values divided by A,’, the expression (27.) will
still result by neglecting merely the difference of those terms.
We must also observe that there is nothing to determine
whether the equations (19.), (20.), give p, = — 1, po = I, or
p,= 1, pp = —1. But, since B, & is incomparably the
largest term in o’, the sign of this quantity must depend on
that of B,; therefore, since the signs of p,, p., depend, by
(20.), on that of o’, it follows that they also depend on that of
B,. This circumstance shows that a change in the sign of
B, does not affect the signs of the last terms either in (18.),
or in (21.), and (26.), derived from (18.). But, since a change
in the signs of ¢,, p 2, causes a change in those of ¢ and tan
a, by (22.) and (23.), it follows that, although a change in
the sign of B, does not affect the velocities v,, v,, it causes
a change in the direction of the angle «, through which the

Phil. Mag. S. 3. Vol. 14. No. 90. May 1839. y

322 Mr. Tovey on the Elliptical Polarization

plane of polarization is turned by the passage of the light
through the crystal. It is well known that different varieties
of quartz turn the plane of polarization in different directions,
the crystals being called right-handed or left-handed accord-
ingly.

We now proceed to investigate the forms assumed, within
the crystal, by the surfaces of waves diverging from any given
point of it. Suppose the coordinates 2, y, z, to originate at
the given point, which denote by O; from O conceive a line
O 2, to be drawn parallel to the axis of the crystal, and let
the axes of z, y, 2, be denoted by Oz, Oy, Oz. Take OF
Ox, Oy, in the same plane, and suppose the molecules to be
so arranged that the system of coordinates may be turned on
the axis O x, without affecting the values of the sums (16.);
then, by art. 4, vol. ix. p. 421, B, will vanish, as we have
supposed, and the values of v,*, 2”. will be expressed, ap-
proximately, by the equations (18.). Hence. we may take

v2? = A,— Ask? — p, sind. Bak,
aie ey aaa sin b. Bak, ; (28.)

The equations (12.) and (13.) give
ue s; E
Pi = ~~ 6! cos 6—o sin b’ (29.)
Re S, ,
P27 cosh + 6 sind’
and therefore, since s, s/ = o!? cos* 6—o? sin? 6, (pres. vol.
page 169,) we find

Pipa. =, ea ; (30.)
hence, by supposing s, nearly equal to s/, we have
Pi) Po = —1, nearly; (31.)
which, by (28.) gives
v7 — v2 = A, — Aj, nearly. (32.)

If we were to leave out of each of the equations (28.) the
two last terms, which are comparatively very small, these
equations would coincide with (3.) of article 6, vol. ix. p.422 ;
whence it follows that the investigation comprised in the ar-
ticles 6—12, of that paper, would apply to the present case,
and, consequently, the forms of the surfaces of diverging, or
converging, waves are nearly the same in quartz as in an or-
dinary mineral crystal. ‘This is confirmed by experiment.

It has been shown, in the investigation just referred to,
that the waves diverging from the point O will consist of two

of Light produced by Quartz: Part I, 325

sets, of which one set will be spherical and the other sphe-
roidal.

Let 7,, ¢,, denote the displacements connected with the
former, and y,, %, those connected with the latter ; then
7 =1,+ m2, $=% + &, and the equations (22.) resolve
themselves into

; 2%
vase {2a
A,
€, = p, a, sin ve (v,—2)—0} >
Ng = a sin jen (v, t—2)},
L Ae
: 20
Co = po @. sin 4 x (vt — )-1\ ‘

19)

(33.)

From these expressions it appears, that, in each set of
waves, the revolutions of the molecules are elliptical. And,
since the equations (31.) show that p, is nearly the negative
reciprocal of p,, it also appears, from these expressions (33.),
that the greater axis of the ellipse of revolution in one of the
sets of waves has the same direction as the lesser axis of that
in the other, and that the revolutions connected with the one
set are performed in an opposite direction to those connected
with the other. We have seen that, when 2x coincides with
the axis of the crystal, we have p, = — 1, p27 = 1, hence we
perceive that the ellipses are then changed into circles; the
motions constituting the two rays being expressed by the
equations (23.). All these deductions are verified by the ex-
periments of Mr. Airy.

Having thus, by the aid of certain probable suppositions
respecting the relative values of the arbitrary quantities,
brought our formule to express the laws of the refraction of
quartz, we may in conclusion observe, that our general in-
tegrals are susceptible of extensive application; and I think
I shall be able to show, in another paper, that they are ade-
quate to explain the cause of the absorption of light. It is
immediately obvious, from the equations (18.), that, for media
possessing, in any degree, the elliptically polarizing structure,
the dispersion-formula must be different from that which has
hitherto been used. I am, Gentlemen, yours, &c.,

Littlemoor, Clitheroe, March 20, 1839. Joun Tovey.

P.S. In the last paper, page 169, line next above the equa-
tion (12.), for b’ read 6; p.171, for Ag in the second line
of (18.) read A',; and p. 174, line 10, for correctly read ap-
proximately.

YQ

[ 324 ]

ul. Observations on some of the Products obtained by the
fieaction of Nitric Acid on Alcohol. By Go.vine Birv,
M.D., F.L.S., G.S., &c. Lecturer on Natural Philosophy at
Guy's Hospital.*

PEW subjects connected with organic chemistry have en

gaged more the attention of chemists than the action
of nitric acid on alcohol, from the discovery of hyponitrous
zther by Navier, up to the present moment. The composi-
tion of what has been long termed sweet spirits of nitre, is
now well determined, and no doubt exists of its being a com-
bination of hyponitrous acid with ether (4C 5H10O+N30).
Some of the products formed simultaneously with this ether
have been less completely and satisfactorily understood ; che-
mists have however for the most part agreed in stating malic,
oxalic, acetic, and carbonic acids to be among the new-formed
products, together with a substance mentioned by Thenard
as “drés facile d charbonner.” Taking advantage of the re-
sidue left in the retort after the preparation of sp. seth. ni-
trici on the large seale, I submitted it to examination and
obtained some interesting and unexpected results. In the
pharmaceutical laboratory of Guy’s Hospital, this ether is
prepared by distilling in a sand-heat two gallons of alcohol
of about *850, and 24 ounces of nitric acid of 1°50, the opera-
tion being stopped when about 34 pints of fluid are left in the
retort. ‘This fluid is straw-coloured, varying in specific gra-
vity from 1°03 to 1:06, strongly acid, and possessing the agree-
able odour of hyponitrous ether. When carefully neutralized
by a sojution of potass it assumed a rich orange-brown tint,
and became slightly turbid; the fluid thus saturated precipi-
tated acetate of lead most copiously, but did not affect the lim-
pidity of lime-water or a solution of chloride of calcium, and
hence did not contain oxalic acid, although this substance is
generally stated to be present in the residue of the distilla-
tion. The most remarkable phenomenon, however, occurred
when some of this carefully neutralized fluid was exposed to
heat in a porceiain bason : as soon as it became warm the co-
Jour deepened m tint, in a short time becoming of a rich cho-
colate brown; a most disagreeable and penetrating odour,
something like that of boiling soap, being evolved: in this ex-
periment the temperature of the fluid did not exceed 160°
Fahr., the change commencing at 115° Fahr., and went on
briskly at 120° Fahr. For the purpose of determining the

* Read before the Chemical Section of the British Association, at New-
eastle-on-T'yne, August 1838: and communicated by the Author.

Dr. G. Bird on the Action of Nitric Acid on Alcohel. $25

nature of the substance concerned in these phenomena the
following experiments were performed.

A. About a pint of the acid yellow fluid remaining after
making sp. eth. nit. was submitted to distillation in a glass
retort, the temperature applied being just sufficient to keep
up gentle ebullition: the first few ounces of fluid that distilled
over possessed the flavour and odour of hyponitrous zether,
and underwent no change of colour by the addition of a so-
lution of potass; after these had passed over and the receiver’
been changed, distillation was carried on until orange-colour-
ed fumes appeared in the retort ; the fluid collected in the re-
ceiver was then removed: its specific gravity was 0°980: it
reddened litmus paper, possessed an odour of «ther mixed
with one so irritating that it produced smarting of the nostrils
and eyes with copious lacrymation ; its flavour was at first
grateful, rapidly however becoming acrid like cayenne pepper,
leaving a burning sensation in the mouth and fauces.

B. To this distilled fluid a solution of pure potass, of spec.
gr. 1:06, was added; the mixture instantly assumed a fine
erange colour, which on the application of a gentle heat
deepened in tint, a strong penetrating “soapy” odour being
evolved.

C. The excess of acid in the distilled fluid was next neu-
tralized with ammonia, and a solution of nitrate of silver
added ; a copious white precipitate occurred, which on being
warmed over a spirit lamp became dark and converted into
reduced silver, giving the fluid a bluish tint when viewed by
transmitted light.

D. From these experiments I at first suspected the pre-
sence of formic acl, as this (as is well known) readily reduces
silver-salts, although the peculiar action of potass is by no
means reconcileable with the known properties of that acid.
To ascertain whether this acid was really present I neutral-
ized exactly some of the distilled fluid with a weak sclution
of potass and evaporated it over a vapour-bath to dryness; a
nearly black residue, containing a few acicular crystals, re-
sulted. ‘This was placed in a retort mixed with sulphuric acid,
and distilled, but not a trace of either formic or acetic acid
could be detected in the distilled fluid, which appeared to con-
tain a small quantity of nitric acid. It hence appeared evident,
that formic acid could not be the reducing agent in Exp. C,
whilst from this circumstance, from the action of potass,
and the peculiar odour, I was led to suspect the presence of
aldehyd.

EK. Some of the distilled fluid was neutralized with potass
and warmed; when it had assumed the orange-brown tint it

326 Dr. G. Bird’s Observations on some of the Products

was poured into some very dilute sulphuric acid; a yellow
powdery deposit fell; this on the application of heat collected
into a resinoid mass, soluble with tolerable readiness in al-
cohol and ether, resembling in its properties the resin of
aldehyd described by Liebig in the second number of his
excellent Handwérterbuch der Chemie. This circumstance,
together with reduction of metallic salts, and the peculiar ir-
ritating soap-like odour, left scarcely a doubt of the presence
of aldehyd. It now became an interesting question to deter-
mine the conditions of the formation of this substance, parti-
cularly as the fluid from which this aldehydiferous fluid had
been separated by distillation copiously precipitated salts of
lime after neutralization by ammonia, indicating the presence
of oxalic acid, which as I have already mentioned was absent
in the residual fluid previous to this second distillation, and
consequently must be considered as a secondary product, re-
sulting from the reaction of nitric acid on some substance
formed in the earlier stage of the operation.

F. Some hyponitrous zther was then prepared without
heat, by Dr. Black’s process, by allowing nitric acid and al-
cohol to react on each other through a stratum of water in a
cylindrical vessel: after the action had continued for two days,
some of the lighter part of the fluid was decanted into a retort ;
it was strongly acid, but smelt agreeably of nitrous ether. On
submitting it to distillation a colourless fluid was collected
in the receiver; that resulting from the earlier part of the dis-
tillation was not at all acrid, nor was it altered by a solution of
potass ; whilst that which came over last was intensely acrid in
flavour, reduced salts of silver after the addition of ammonia,
and underwent those changes with weak solutions of potass
which characterize aldehydiferous fluids. This experiment
was by no means satisfactory as showing the formation of
aldehyd by the action of nitric acid on alcohol in the cold, in
consequence of the acidity of the fluid previous to distillation ;
enough nitric acid being probably present in the retort to
produce this peculiar substance by the reaction on alcohol
or zther on the application of heat. ‘To determine this fact
with greater accuracy, some of the acid zther prepared by
Dr. Black’s process was digested with protoxide of lead and
then distilled over some of this oxide: the fluid in the receiver
was very mild in flavour, of spec. gr. 0926, and underwent
no change in colour by the addition of alkaline solutions: it
was also destitute of action on salts of silver; hence the abs-
ence of aldehyd may be safely inferred. From this cireum-
stance we may conclude that this curious substance is by no
means a necessary result of the action of nitric acid on alcohol

obtained by the reaction of Nitric Acid on Alcohol. 327

during the formation of hyponitrous ewther. The acid fluid
left in the cylinder in Dr. Black’s process, after these two
portions of zther had been decanted, was set aside very loosely
covered with a glass plate. In the course of a few days it
evolved a pungent odour of acetic acid; it was neutralized
with carbonate of soda, and evaporated to a small bulk; nu-
merous crystals of nitre appeared ; the supernatant fluid was
evaporated to dryness: a crystalline and exceedingly deliques-
cent mass resulted; this when treated with sulphuric acid
evolved copious fumes of acetic acid.

I next turned my attention to the non-volatile products re-
sulting from the action of nitric acid on alcohol. Some of
the residual fluid in the retort, after preparing sp. eth. nit. on
the large scale, of sp. gr. 1:06, was carefully saturated with
carbonate of soda: the neutral fluid after being warmed to get
rid of carbonic acid did not trouble solutions of chloride of
calcium, and was therefore free from oxalic acid; a solution
of acetate of lead was added until no further troubling en-
sued ; the copious precipitate that fell was collected, well
washed, and drained on a filter. This substance was dif-
fused through water, and submitted for twelve hours to a cur-
rent of sulphuretted hydrogen until no more gas was taken
up. The mixture was boiled and filtered. The colourless
fluid thus obtained was acid, but by very careful evaporation
did not evince any tendency to crystallize: it was divided into
two portions; one was carefully neutralized by ammonia and
the unsaturated portion added. By very careful evaporation
over a vapour-bath delicate acicular crystals of an acid am-
moniacal salt were obtained. These crystals did not contain
malic acid, the presence of which I had expected, for the pre-
cipitate their aqueous solution yielded with salts of lead did
not dissolve in any appreciable quantity in hot water, nor did
it fuse at 212°. As far as I have examined the acid combined
with the ammonia in these crystals, I am disposed to regard
it as that which has long been confounded with malic acid,
viz. oxal-hydric acid, a substance produced by the action of
nitric acid on many of the products of organization, often simul-
taneously with oxalic acid (4C 3H6O) = 4C,60+4 3H.

A fresh portion of the fluid left after the distillation of
nitrous «ether was evaporated slowly to a syrupy consistence ;
nitrous acid fumes appeared in abundance: the whole being
allowed to cool deposited in a few hours numerous crystals,
which were readily distinguished as those of oxalic acid. The
mother liquor was decanted, and submitted to fresh evapora-
tion and set aside: by cooling, delicate foliaceous crystals, pos-
sessing the pearly lustre of cholesterine, appeared in the fluid ;

328 Dr. G. Bird’s- Observations on some of the Products

these were separated and drained on filtering paper: on -be~
ing subsequently examined, they also proved to be oxalic
acid like the first formed crystals, from which they altogether
differed in their physical characters. I am quite unable to
account for the curious forms assumed by the second crop of
oxalic acid crystals; not having submitted them to analysis
I cannot state whether they contained the same quantity of
water of crystallization as those possessing the ordinary cry-
stalline form.

Having thus shown that oxalic acid is not a constant pro-
duct during the preparation of nitrous ether, at least in the
earlier stages of the operation, I was anxious to ascertain
whether the evolution of aldehyd and formation of oxalic
acid bore anything like a mutual relation. For this purpose
the following experiment was performed. A quantity of the
fluid left in the retort after the preparation of sp. ath. nitrici
was placed in a tubulated retort, and a quilled receiver was
so adapted as to allow a receiving bottle placed beneath to
be changed and removed at will. A sand-heat was then ap-
plied and distillation commenced: when about one fourth of
the fluid had passed over, the receiving bottle was charged
and the fluid examined; it was colourless, aromatic, of sp. gr.
0°861, was unaffected or nearly so by the addition of alkaline
solutions, and appeared to be merely an alcoholic solution of
hyponitrous ether which had not been completely removed
by the operation on the large scale. Some of the fluid in the
retort was removed and examined; it was nearly totally free
from oxalic acid, and appeared to contain among new pro-
ducts only the oxal-hydric acid. Heat was again applied to
the retort, and about a third of the remaining fluid was di-
stilled over; this was of sp. gr. 0°872, exceedingly acrid, like
capsicum in flavour, acid, and assumed a deep orange tint by
the addition of solution of potass even in the cold; this in-
creased by heat, and the subsequent addition of dilute sul-
phuric acid produced a copious deposition of the resin of
aldehyd. The fluid in the retort contained a large quantity
of oxalic acid, formed probably by the reaction of the free
nitric acid present upon the oxal-hydric acid formed in the
first stage of the operation. Upon a third application of
heat distillation was carried on until red fumes appeared ; the
fluid in the receiving bottle was of sp. gr. 0°972, very acid,
scarcely contained any zther, and much less aldehyd than
the portion previously distilled, as it was merely tinged yel-
low by potass: the fluid left in the retort was so loaded with
oxalic acid that it crystallized by cooling.

From these experiments, one fact at least of pharmaceutical

obtained by the reaction ef Nitric Acid on Alcohol. 329

importance may be inferred, viz. that in preparing the sp.
zth. nitrici for medical uses, the distillation ought to be
stopped when oxalic acid appears in the retort, to avoid the
presence of aldehyd in the distilled fluid, and consequently
that the limitations with regard to the quantity of product
obtained, mentioned in the Pharmacopeeia, should be strictly
attended to, as the presence of so pungent and irritating a
fluid as aldehyd in the sp. zth, nit. of the shops, cannot but
interfere considerably with the cooling febrifuge uses of the
latter. I may remark, that asin the preparation of this zther
on the large scale it is of importance to the manufacturer to
obtain as large an amount of product as possible, we find, as
might be expected, traces of aldehyd in most commercial spe-
cimens of the zxether, which indeed is indebted to it for that
pungent acrid flavour it so frequently possesses. If the di-
rections of the London Pharmacopeeia be observed, the pro-
duct is always free from aldehyd; this I have verified in several
instances in numerous specimens prepared in the pharmaceu-
tical Jaboratory of Guy’s Hospital, as well as in that of my
friend Mr. R. Phillips, of St. Thomas’s Hospital.

In conclusion, I may be permitted to submit the following
as the inferences deducible from the foregoing observations :

1, That in the preparation of sp. eth. nitrici, as long as
the latter with alcohol only distils over, no oxalic acid is
produced, an acid which appears to be identical with the
oxalhydric only appearing in the retort.

2. That on continuing the distillation beyond this point,
the free nitric acid in the retort reacts on the oxalhydric and
produces oxalic acid.

3. That in the action of nitric acid on alcohol in the cold
as in Dr. Black’s process for the formation of hyponitrous
zether, acetic acid is copiously produced, instead of, or in ad-
dition to, oxalhydric acid.

4. That aldehyd (as has been before shown by chemists) is
produced by the action of nitric acid on alcohol, but that it
is not formed in any quantity, or at least does not appear in
the distilled fluid, until the formation of hyponitrous zther
has nearly or altogether ceased.

5. That the production of aldehyd and oxalic acid are
nearly simultaneous, and that both these appear to result
from secondary action of nitric acid upon products formed in
the early stages of the operation.

6. That the “ crystals of Hierne” formed when distillation
is carried on until red fumes appear are oxalic acid, notwith-
standing their remarkable micaceous form; and that the sub-

330 M. Plateau’s Defence of his Theory of the Visual

stance tres facile a charbonner, mentioned by Thenard, is pro-
bably aldehyd, which from its behaviour towards alkalis
might apparently merit that character.

LIL. Answer to the Olyections published against a general
Theory of the Visual Appearances which arise from the Con-
templation of Coloured Objects. By J. PLarEau, Professor
at the University of Ghent.

To the Editors of the Philosophical Magazine and Journal.

GENTLEMEN, Ghent, April 15, 1837.+
] HAVE the honour to transmit you herewith an article
which I should thank you to insert in your Journal.
Although the main object of this paper is not to make known
new facts, you are well aware that theoretical discussions are
not void of interest with regard to science. Besides, when a
theory is attacked, it is naturally to the organs of scientific
publicity that the office belongs to furnish the author of that
theory with the means of defending his ideas. As it was in
England that the principal objections against my statements
appeared, and as a part of those objections were published
in your Journal; lastly, as my article contains a mere scien-
tific defence, I make no doubt, Gentlemen, that you will
willingly devote your pages to it, and do me the favour to
insert it in your next Number.
. I remain, Gentlemen, yours, &c.,
Ju. PLATEAU,
Professor at the University of Ghent.

In publishing my theory on the visual appearances which
succeed the contemplation of coloured objects, and on those
which manifest themselves during that contemplation {, I con-
ceived that if this work deserved any attention, it was princi-
pally on account of the generality and simplicity of the point
of view under which I have united four different classes of
phenomena whose affinity to each other has not been acknow-
ledged ; namely, he duration of impressions on the retina, the

+ This communication, as I subsequently learnt from M. Plateau, was
forwarded from Ghent at the date which it bears, and having, after being
long given up for lost, at length come to hand through some unknown
channel, it is now published without further delay —R. T.

+ See An. de Chim. et de Physique of Messrs. Gay-Lussac and Arago,
August 1833, page 386, and April 1835, page 337. Supplement to the
Treatise on Light of Sir J. Herschel, by M. Quetelet, page 515. Memoirs
of the Academy of Brussels, tom. viii.

oe

Appearances from the Contemplation of Coloured Olyects. 331

accidental colours by succession, the irradiation, and the. acci-
dental colours by simultaneousness, or the effects of the guxtapo-
sition of colours. Above all, I should have thought that if
my inquiries had given rise to any refutation, it would have
been directed against my general principle, against the law
of continuity on which I have made these various pheenomena
depend: however such has not been the case. It is true, se-
veral objections have appeared; but they merely relate to
some particular facts, or at most to that class of phenomena
which constitute the accidental colours of the first-named
species.

Be that as it may, I shall successively examine these dif-
ferent objections; but in order to make them more easily ap-
preciated, it will be necessary first to restate summarily the
principles of my theory.

I have divided the appearances in question in two large
sections: the first comprehends those which succeed the con-
templation of objects; that is to say, the duration of impres-
sions, and the accidental colours by succession, or which show
themselves after the disappearing of the objects which pro-
duce them. In the second are contained the appearances
which accompany the contemplation of objects: that is to say,
the irradiation, and the accidental colours by simultaneousness,
or which manifest themselves in presence of the objects look-
ed at.

Now, if we consider that the phenomena of the first section
are produced from the moment when the object ceases to act
upon the retina, to the one in which the organ recovers its nor-
mal state, and that, on the other hand, those of the second
section surround, on the retina, the space directly excited
by the light, from the contour of that space to those parts of
the organ which remain in their normal state, we may say that
the first constitute, in the organ, the passage from the state
of excitation to the normal state with regard to time, and that
the others constitute the passage from the state of excitation
to the normal state with regard to space.

Upon examining the laws which regulate each of these
passages, I have remarked a very striking analogy between
them; the one being, as it were, but the translation of the
other, by substituting space for time. The facts already known,
together with my own observations, have induced me to ac-
knowledge that these laws are as follows.

In the first case, that is, in the passage with regard to time,
the retina being suddenly left to itself after an excitement
sufficiently prolonged, retains for some length of time this
same state of excitement, which gradually vanishes, to give

332 M. Plateau’s Defence of his Theory of the Visual

place to a state of nature directly opposite. ‘The first of these
two effects constitutes the duration of the primitive impression,
and the second the apparition of the complementary accidental
colour. ‘These are the most manifest effects: but afterwards
the impression almost always undergoes oscillations more or
less regular: frequently the only effect perceived is the acci-
dental colour which alternately appears and disappears; but
in certain circumstances, the accidental colour alternates
with recurrences of the primitive colour, so that the impres-
sion then passes alternately into two opposite states, till it com=
pletely vanishes.

In the second case, that is, in the passage with regard to
space, the state of excitement in the retina extends itself to
a small distance round the portion directly excited by the
jight, and beyond that is manifested a state of nature directly
opposite, from which results the sensation of the comple-
mentary colour, The first of these two phenomena consti-
tutes zvradiation, and the other the second species of acci-
dental colours, or the effects, so ably analysed by M, Che-
vreul, of the juxtaposition of colours. ‘Vhese two principal
phenomena are commonly the only ones manifested ; but in
favourable circumstances, beyond the space occupied by the
complementary colour, the primitive colour is again to be
found, though much weakened ; so that oscillations as to time
are here substituted, to a certain degree, by oscillations as to
space, if I may be permitted so to express myself.

In order to render the statements of the facts more easy, and
to recall the opposition between the primitive and comple-
mentary impressions, I have named the first positives, and the
second negatives.

Now the discussion of the pheenomena of the first section
has induced me to make them depend upon the general prin-
ciple which follows :

When the retina is submitted to the action of the rays of any
colour whatever, it resists that action, and tends to recover its
normal state, with a gradually increasing force. Then, if the
organ be suddenly withdrawn from the exciting cause, it returns
to the normal state by a sort of oscillatory motion, the more in-.
tense as the action has been further prolonged, a motion in
virtue of which the impression passes first from the positive to,
the negative state, and then continues generally to oscillate, in
a manner more or less regular, by becoming weaker, until it has
entirely vanished.

Hence the successive opposite states of the impression would
be analogous to the successive positions of a body removed
from a stable equilibrium, and which alternately transports

Appearances from the Contemplation of Coloured Objects. 333

itself from one side to the other of its original position of re-
pose, until its movement be completely annihilated. Besides,
as I have said in the publications wherein I have made known
my theory, I consider this principe of oscillations as general;
that is to say, applicable to any organ whatever, and even to
moral phenomena.

With respect to the appearances of the second section,
they may be compared to the alternations of the two opposite
electricities in an insulated conductor which is submitted to
the influence of an electrified body; or likewise to the phee-
nomena which a circular plate presents whose centre is made
to vibrate, and in which opposite vibrations are separated by
circular lines of repose, &c. ‘

Thus the phenomena of the first section would be the ef-
fects of the same law of continuity and inertia that we: see
manifested in a great many instances, when a body removed
from a state of stable equilibrium is afterwards suddenly left
to itself; and those of the second section would be equally
the effects of an analogous law of continuity, which is fre-
quently manifested when only a portion of a body is main-
tained, in one way or other, in a state differing from its nor-
mal state.

The foregoing is a summary of my theory of visual appear-
ances. With regard to the series of proofs upon which I have
grounded it, I can only refer to the papers already quoted in
the note. The first article of the Annales de Chimie et de
Physique, as well as the note inserted in the Supplement to
the work of Sir J. Herschel, are nothing more than summary
expositions of the ensemble of my work; but the memoir
contained in the collection of the Brussels Academy, and in
the number of April 1835 of the Annales de Chimie et de
Physique, is a complete development of that part of my in-
quiries which relates to phenomena of succession, or of the
first section. I am now occupied with the second part of this
memoir, that is to say, with that which embraces phenomena
of simultaneousness, or of the second section.

We shall now pass to the objections. The first which
came to my cognizance were advanced in an anonymous ar-
ticle of the Edinburgh Review (number for April 1834, page
160, and following*.) Unluckily, the author had no know-
ledge of my theory but from the first of the two summary
expositions of which I have just spoken, and he was conse-
quently not able to judge of it with thorough competence.

* The reader may consider that my answer has been a long time de-

ferred, but it was only very recently that I knew of the objections in
question,

334 M. Plateau’s Defence of his Theory of the Visual

His first attack is directed against one of the proofs by
which I intend to establish an opposition of nature between
accidental and direct impressions. My proposition was thus
expressed * :—

‘‘ In the cases where the combination of real colours pro-
duces white, the combination of accidental colours produces
the contrary to white, or black. Whereas, for instance, two
real complementary colours produce together whzte, two ac-
cidental complementary colours produce together black.

“‘ This fact may be ascertained by an experiment: place
ona black ground a rectangle of paper, the two halves of
which are painted with two complementary colours, for in-
stance red and green, as indicated by the fig. 1. +, the middle
of each coloured portions being marked with a black point.
Then, if you alternately direct your sight from one of these
points to the other, for a sufficient length of time, the result
will be an image, in the bottom of the eye, formed by the su-
perposition of the accidental green produced by the red half,
and of the accidental red produced by the green half; or, in
other terms, by the superposition of two complementary ac-
cidental colours. Now, if you suddenly and completely cover
your eyes with a handkerchief, this image will appear perfectly
black, having on the right hand a red image, and on the lett
a green image (supposing that the green and red halves of
the rectangle be placed as in the figure). The production
of these two lateral images sufficiently explains itself.”

I shall here subjoin some particulars for persons who may
wish to repeat the experiment. The rectangle I employed
was 20 centimetres long by 10 high, and the ground on which
I placed it was a large black shawl spread on the floor, in a
light room. I stood with my back to the windows, but so as
not to throw a shadow on the object. I then directed my
sight alternately on the two black points, looking at each of
them for nearly a second, and I continued thus about the
space of a minute, after which I covered my eyes, as I before
said.

These are now the objections. The anonymous author be-
gins by saying that this property of accidental colours advanced
by me, must appear, at first sight, an important one, but that
a slight examination of the subject will show, “ that this pro-
position is a verbal illusion, and that the physical fact which
it so erroneously expresses, has been long known to philoso-
phers.”

* Ann. de Chimie et de Physique, August 1833, p. 388.

+ In the figure which accompanies the article, (in the Ann. de Chim.) the
green half of the rectangle is on the right, and the red half on the left.

Appearances from the Contemplation of Coloured Olyects. 335

** Anaccidental colour,” says he in continuation, “ is some-
thing essentially distinct from a colour produced by the action
of direct rays. The rays which produce ordinary colours,
can be combined in any proportion we please; and the re-
sulting effect is the sum of the actions of each separate ray
upon the retina. Hence all the different colours of the spec-
trum produce a purely white beam of light; and perfect
whiteness may be also produced by two compound colours,
one of which is complementary to the other. An accidental
colour, however, cannot be added to, or combined with an-
other. When the eye sees an accidental colour, suppose red,
the excited part of the retina is insensible to all other rays
but those of the accidental colour. If we instantly excite the
same portion of the retina with another light, which is an ac-
cidental green, and thus render it insensible to red, then the
eye will see blackness, not because the accidental red and the
accidental green compose blackness, but because the eye has
been in succession rendered insensible to the two colours
which compose white light itself.”

Thus the author founds himself upon the hypothesis which
attributes accidental colours to a diminution in the sensibility
of the retina, as if that were a demonstrated truth. But Lhave
shown at the beginning of the article against which the ob-
jections are directed, that this hypothesis is insufficient to ex-
plain the phenomena. I have stated in proof of it this fact :
** that accidental colours are perfectly seen in the most com-
plete obscurity.” In fact, in the hypothesis adopted by the
anonymous author, the accidental colour, for instance, red,
which succeeds the prolonged contemplation of a green object,
is explained by saying that the retina fatigued by this con-
tinued excitation of green light, loses its sensibility to. this
light, and is then only affected by the rays which form the
complementary red tint. This ingenious theory perfectly
explains the phenomenon, when, fishing to see the accidental
colour, we cast our eye on a white surface, as is usually prac-
tised. For then we can admit that the red rays, which enter
into the composition of whiteness, alone act on the retina.
But what does that explanation amount to, when applied to
the accidental colour seen ina complete obscurity, and when,
in consequence, no ray reaches the eye that can give the sen-
sation of the complementary tint? Now it is by placing my
eyes in that condition, as above indicated, that I have observed
the result of the combination of two accidental colours com-
plementary to each other ; and it is precisely in order to ren-
der impossible the explanation of the fact by the diminution

336 M. Plateau’s Defence of his Theory of the Visual

of sensibility of the retina in regard to certain rays, that I
have thus made the experiment.

But the anonymous author alleges that an accidental co-
lour cannot be added to, or combined with another. To
which I answer by referring him to paragraph 24 of the dis-
sertation of Father Scherffer*, one among the philosophers
who have made the greatest researches on the subject of ac-
cidental colours, the one precisely who has furnished us with
the theory which attributes the phenomena toa partial dimi-
nution in the sensibility of the organ. In this paragraph,
Scherffer relates direct experiments whereby he convinced
himself that the accidental colours combine perfectly well to-
gether. If the anonymous author maintains that these ex-
periments can be explained by the diminished sensibility,
seeing that Scherffer observed the results of the combination
by casting his eye on a white wall, I shall answer that the
effects are the same in a complete obscurity, as may be easily-
ascertained, by substituting for the red and green rectangle
of my experiment an orange and green one. ‘Then, if the
same process is used, three coloured images will be seen,
whose intermediate one will be violet. This image is the re-
sult of the combination of the blue and red accidental colours.

Consequently, accidental colours are really susceptible of
combinations, and the resulting tints are the same as in respect
to real colours, except the case in which the two composing
accidental ones are complementary to each other. In this
latter circumstance, since the result is blackness, it appears
to me that I have not expressed the fact erroneously, by saying
that two complementary accidental colours produce together
black, which signifies, if you will, that they mutually destroy
each other.

It is difficult for me to conceive how the anonymous author
has not paid attention to this circumstance formally expressed
in my article, that it is in a complete obscurity I have observed
the phenomena. For this is a chief point in my theory of ac-
cidental colours, and totally excludes all the explanations
which may be founded upon a diminution of sensibility to
certain rays. ‘The author thus continues :—

“¢ If Buffon, or Dr. Darwin, or Count Rumford had been
asked what would be the effect of exciting the retina in quick
succession with all the simple colours of the spectrum, or
with two compound colours which compose white light, they
would all have immediately answered, b/ackness. M. Plateau

* Journal of Physics, by Rozier, tem. xxvi. year 1785, p. 282.

Appearances from the Contemplation of Coloured Objects. 337

has therefore, in this part of the inquiry, merely expressed
what has been long known, in language physically incorrect,
and calculated to convey very erroneous notions on the sub-
qect.”

Indeed, the philosophers the author speaks of, might have
made the answer he attributes to them (except however Buf-
fon, for the theory of the relative insensibility did not appear
till a long time after), because they would have supposed that

Oo . .
the effect was observed by casting the eye on a white surtace.

But if they had been asked what should be the effect in a
total obscurity, they would doubtless have said that the deci-
sion depended on experience. I have therefore not merely
expressed what has been long known.

We now come to the other objections.

** Plateau maintains,” says the anonymous author, “ that
after the direct or positive impression of the primitive colour
has continued visible for a certain time, and gradually faded
away, it is succeeded by the viegative impression, or acci-
dental colour. But what is original in his theory he maintains,
that after the accidental colour has faded away in its turn, 7¢
as succecded by the primitive colour, this alternation going on
tll the impression wears away. If we look into the volume
already quoted *, we shall see that the only novelty in Pla-
teau’s theory is the recurrence of the primitive impression,
and the continued alternation of the two; but we do not think
that this recurrence and alternation are established by sufii-
cient evidence; at least, we cannot by any contrivance render
it visible. It is certain that the accidental colour disappears
and returns, and undergoes other changes; but these changes,
we conceive, are not the effect of the primitive impression, or
a continuation of a necessary series of changes, of which the
primitive impression is the commencement; but the result
of subsequent actions upon the retina, which M. Plateau has
not been careful enough to detect and analyse. It has been
proved, for example, that a pressure upon the retina with the
finger changes the accidental colour, and it is asserted by Sir
Charles Bell, that if we squint or distort the eye, a vivid im-
pression on the retina instantly disappears, as if it were wiped
out. When M. Plateau, therefore, saw the accidental colour
change into the primitive, was he sure that there was no press-
ure made upon the retina by the motion of the eye, or by
the involuntary closing even of the eyelids, which is sufficient
to produce the observed change? That the changes of colour

* This work is the Treatise on Optics of Sir David Brewster, forming
a part of the Cabinet Cyclopedia, and in which this philosopher has also
presented a theory of accidental colours.

Phil. Mag. S. 3. Vol. 14. No. 90. May 1839. Z

3388 M. Plateau’s Defence of his Theory of the Visual

in question are not regular, and are produced by some irre-
gular influence, may be inferred from M. Plateau’s own ob-
servation, that the alternations of colour do not always take
place in the same manner, that they vary with the sensibility
of the eyes, and particularly with the circumstances under which
the experiment is made; and he afterwards remarks, that the
regular alternation of the primitive and accidental colour zs
the effect most frequently observed. Now this additional fre-
quency of one phenomenon ina series is no proof of a regular
law; and when we consider how the retina is affected by the
state of the stomach, by the pressure of the blood-vessels,
which may, in some cases, be an intermitting cr an alterna-
ting one, we must demand a series of distinct experiments
made with the same result, on the eyes of different observers
accustomed to the examination of this class of phenomena,
and aware of the causes which exercise a disturbing influence,
before we can admit the conclusion drawn by M. Plateau.”

The anonymous writer is strangely mistaken, if he supposes
that I attach any value to the novelty of my experiments. In
support of my theory, I should have considered it more ad-
vantageous, had I only to relate facts before ascertained. For,
with respect to pure phenomena of sensations, more than in
any other circumstance, it may be supposed that the author
of a theory is influenced in his judgements, in spite of him-
self; by the desire of reconciling the facts with his system.
Accordingly, in my detailed memoir, I have endeavoured, as
much as possible, to establish my statements on anterior ob-
servations; and, when this resource failed me, I was most
careful in requesting other persons to repeat my experiments.
For instance, with respect to the recurrence of the primitive
impression, a recurrence that the anonymous author was not
able to observe, I have quoted, in my memoir, the following
experiment related by Rozier, the editor of the Journal of
Physics * :

«* Suppose,” says he, ‘ any apartment, either deprived of
the sun’s light, or at least in the moment when it can be said
that it is neither day or night (the experiment succeeds better
in the first case). Suppose in this apartment a candlestick
furnished with a lighted wax taper; the light of a candle or
lamp producing the same effect. Place this candlestick at
your feet, on the floor ; look at this light perpendicularly, so
that your eyes remain fixed on it without interruption for se-
veral moments. Immediately after, place an extinguisher on
this light, lift up your eyes to the wall of the apartment, fix

* See this Journal, tem. vi. page 486, year 1775.

Appearances from the Contemplation of Coloured Objects. 339

your sight towards the same point, without winking the eye;
you will see nothing but darkness at the beginning of this
operation, after that, towards the point you look at, there
will appear a much greater obscurity than that of the remain-
der of the apartment. Continue thus to keep your sight
steadily fixed; gradually in the middle of this obscurity, a
reddish colour will manifest itself; it will become insensibly
enlivened, its brightness will increase, and at last it will ac-
quire the colour of the flame.”

Thus, in this experiment, the obscure negative image, that
is to say, contrary to the brilliant impression of the flame,
was gradually changed into a new luminous image having the
colour of this flame; that is, into a positive image. I must
here remark, that Rozier recommends fo fix the sight towards
the same point without winking the eye, and further, to keep the
sight steadily fixed, so that these precautions remove every
supposition of pressure or distortion of the eyes, which could
alone, as the anonymous author maintains, cause the image
tovary. I shall add, that this experiment has not been made
with the view of giving weight to any theory; Rozier presents
it simply as a fact that he does not seek to explain. With re-
spect to more multiplied alternations of the two impressions,
alternations which the anonymous author has not been more
successiul in verifying, unluckily no one, as far as I know,
had noticed them before me. For which reason I have taken
care to associate other persons with myself, who have experi-
enced the same effects, and I have cited among them M.
Quetelet, a name which ought to inspire the fullest confidence
(see my article of Annales, page 392). 1 will here relate the
experiment such as I describe it in that article, pages 393
and 394.

‘* I applied to one of my eyes a black tube about 50 centi-
metres long by 3 in diameter, at the same time covering the
other eye completely with a handkerchief, and I looked stead-
fastly, during a minute at least, on a red paper exposed to a
clear day-light; after which, withdrawing the tube suddenly
without uncovering the other eye, I looked at the white ceil-
ing of the apartment. I then saw a green circular image,
which, after some time, gave place to a red one of a feeble
intensity indeed, and of a very short duration, but perfectly
visible ; afterwards, the green colour reappeared, which, soon
after, was again succeeded by a reddish image, and thus three
or four times successively, the two opposite impressions being
less and less intense.”

I shall only subjoin that the coloured paper ought to be
sufficiently large for its edges not to be perceived. In this

Z2

340 Prof. Johnston on the

experiment I have seen as many as nine oscillations of the
impression produced, that is to say, five transitions from the
positive to the negative, and four from the negative to the
positive. With regard to disturbing causes which might,
according to the anonymous author, have occasioned these
modifications in the impression, I must, if such had pre-
sented themselves, have been a very unskilful observer, not to
have noticed their influence, nor have secured myself against
them. I must moreover say that with respect to myself the
accidental colours are not so fugitive, and that they by no
means disappear from my eyes by distorting them, squinting,
or closing the eyelids.

The anonymous author is again mistaken, in attributing to
me this assertion, that the regular alternation of the primitive
and accidental colour 1s the effect most frequently observed.
have, on the contrary, said (page 392 in the article of the
Annales), that the effect most frequently observed was that
of the disappearances and reappearances of the negative or
accidental impression alone. And indeed, among the philo-
sophers who have made researches on accidental colours, many
have taken notice of this fact, as, for instance, may be seen in
the memoirs of Scherffer and Darwin.

The reader may see from what precedes, that the facts
I have advanced are not deficient in authority, as the anony-
mous author seems to allege; he has there limited his ob-
jections; let us, therefore, proceed to those which have been
raised by other persons.

[To be continued. ]

LILI. On the Constitution of the Resins. By James F. W.
Jounston, Esq. F.B.S., Professor of Chemistry and Mine-
ralogy in the University of Durham.

To Richard Phillips, Esq.
My pear Puiuuirs. Durham, March 20, 1839.
HE more I study the constitution of the resins the more
interesting does it become ; and J begin now to consider
them as presenting one of the most beautiful natural families
to be met with in the entire range of organic chemistry. In
my last letter I gave you an outline of some of the results at
which I had then arrived. You will be interested probably
in learning the further development I have already been able
to give them. ‘This will best appear by presenting to you an
outline of the classification of the resins, so far as they have
yet been analysed.

General Irrational Formula = Cy Hyo42 OY

Constitution of the Resins. 241

Group Tt =, Hi... 0
IH. = Cy Hy .Oy
In these groups x can never exceed 8, and there may be
other groups, none of the members of which are yet known,
of which H,_» Hyg-2, Hao-2, may form the middle term.
Each of these groups is divisible into many subgroups, in
each of which y is represented by a different number. Thus

Group I., = Cy Hy-.Oy

Subgroups. To which belong
f Anime resin = C,, Hz,0, Laurent.
A = Cy Boo 1 { Fossil copal = Co HH, O, Johnston.
Elemi resin = C,,H,,O, Rose.
B= Cy Hy2 O, 4 Mastic ete: Cy H,,0, Johnston.
Anime B
C= Cy A322 Os 4 Copal B \ = Cy H3;,0; do.
Colophony = C,H, 0, Liebig.
D = Cy Hy» Or Modif f = C., He Os Johnston.
Lod ie
| sataphouy Spy eA
EC, H,_, O, 4. Modified
fo mMastig A == Oy Fl Oe do.
{ JuniperA

Resin of
Pe VO; Guyaguil fe ts Os: do.
Asphaltene ? = C,,H;,O, Boussin-
G = C,, H;,-,O, noexamples yet known. gault.
Pasto var-

nish \ = Cy HO, do.
H = Cy Hy.» Os ie se = C,,H,,O, Johnston
= ao F431 Vs :

resin
Group tI. — C, H,,.,\07
Subgroups. To which belong
Rete art Resin of dragon’s blood = C,) H,, O;
ew S| Resin of gamboge = OF Es, On
B = Cy Hoy» Oj) Resin of guiacum = C,H. O01,
C=C, Hy. Oj, Acaroid resin Kg 2 OK 0 Be

This second group I have only just established, and other
subgroups will present themselves in the progress of the in-
vestigation. You will observe that the subgroups compre-
hend divisions in which the equivaients of hydrogen vary so
that the number of substances which may belong to this na-
tural family is almost endless. ‘The details of the analyses

342 Mr. Ivory on the Theory of the Astronomical Refractions.

from which the above, and other results are deduced, will be
laid before the Royal Society.

The salts of the resins have also occupied much of my at-
tention, but I have not yet been able to satisfy myself as to
their constitution. So far is clear, that in combining with
bases the resins do not give off the elements of water. There
is a difference I suspect in the number of equivalents of hy-
drogen present in the resin when combined and uncombined,
but the exact nature of that difference requires further eluci-
dation.

Though you do not favour symbolic expressions in che-
mistry very much, I hope you will allow that there is consi-
derable beauty in the hasty generalizations I have here given
you. Believe me, my dear Phillips,

Yours very truly,
James F. W. JoHnston.

LIV. The Bakerian Lecture-—On the Theory of the Astro-
nomical Refractions. By James Ivory, K.H., M.A,
F.RS. L. & E., Instit. Reg. Sc. Paris, Corresp. et Reg. Sc.
Gottin. Corresp.

[Continued from p. 287. ]

3. ig appears that Newton himself was the first to apply
this new method to the problem of the astronomical
refractions. A table, which he had computed, and which he
gave to Dr. Halley, is published in the Philosophical Trans-
actions for 1721. Nothing is said as to the manner in which
the table was constructed; and it has always been a curious
and interesting question among astronomers, whether it is the
result of theory, or is deduced from observations alone with-
out the aid of theory. Some original letters of Newton to
Flamsteed, published in 1835 at the expense of the Board of
Admiralty, have put an end to all doubts on this point. These
letters prove that Newton studied profoundly the problem of
the refractions; that for several months in succession he was
occupied almost entirely in repeated attempts to overcome the
difficulties that occurred in this research; during which time
he calculated several tables with great labour, namely, the
one he gave to Halley, and another, or rather three others,
which have been found in his letters to Flamsteed lately
printed.

Admitting that the refractive power of the air is propor-
tional to its density, which Newton had established in his
Optics on speculative principles, and which Hawksbee after-
wards was the first to demonstrate experimentally, the mathe-

Mr. Ivory on the Theory of the Astronomical Refractions. 343

matical solution of the problem requires a knowledge of the
law according to which the densities vary in the atmosphere.
In his first attempt Newton assumes that the densities de-
crease in ascending in the same proportion that the distances
from the earth’s centre increase. Now a and r denoting the
same thingsas before, put / for the total height of the atmo-
sphere; then ¢ () the refractive power of the air at the di-
stance r from the centre of the earth, will, according to this
hypothesis, be expressed by the formula
> (p) = o(¢’) x oat

If this value be substituted in the formula (1.), which is a
deduction from the sixth proposition of the first book of the
Principia, the result will be

ds

o ,
dng = Sle) aS .rdn

In this expression we have
dtr 1 1

dat 7 a 1486 (6)
and as 2¢(p), or the increment of the square of the velocity
of the light is very minute, amounting to less than ‘0006 in
passing through the whole atmosphere to the earth’s surface,

we may reckon

dr? ;
dé as unit; thus we get

/
d.36= ae

TACT

and by integrating
b= TO) EO
ica : st
a

This result, which M. Biot has also obtained, is equivalent
to the geometrical construction communicated by Newton to
Flamsteed in a letter from Cambridge, December 20, 1694.
The problem was now reduced to the quadrature of a curve,
for which a general method is given in the fifth lemma of the
third book of the Principia, a method which is still used when
the direct process of integration fails, or becomes too intricate
for practice. What has been said not only proves the exact-
ness of Newton’s solution of the problem; it also points out,
with little uncertainty, the manner in which he obtained it.
Of the arithmetical operations of the quadrature there is no
account; and they would be of no interest had they been

844 Mr. Ivory on the Theory of the Astronomical Refractions.

preserved. He complains much of the great labour of the
numerical calculations; but all difficulties were overcome, as
was to be expected: a table was computed and communicated
to Flamsteed in a triple form, for summer, winter, and the
intermediate seasons of spring and autumn. On mature re-
flection there occurred to him a serious objection to the sup-
posed scale of densities, on which account he writes to Flam-
steed that he does not intend to publish the tables. The fault
lies in this, that the centripetal force which continually in-
flects the light to the earth’s centre, is the same at all the points
of the trajectory, or, in the words of Newton, the refractive
power of the atmosphere is as great at the top as at the bot-
tom,—than which nothing certainly can be more different
from what actually takes place in nature.

Dismissing his first hypothesis, Newton next turned his at-
tention to the 22nd proposition of the third book of his Prin-
cipia. If the atmosphere consists of an elastic fluid gravi-
tating to the earth’s centre in the inverse provortion of the
square of the distance, and if it be admitted t nat the densities
are proportional to the pressures, Newton, in the proposition
cited, proves in effect that the densities will form a decreasing
geometrical series, when the altitudes are taken in arithme-
tical progression*. He writes to Flamsteed that an atmosphere
so constituted is certainly the truth. Newton evidently in-
tended by this assertion to mark a distinction between press-
ure, which is a cause of the variation of density that actually
exists in nature, and his first assumed law of the densities,
which is entirely arbitrary. Setting aside hypothesis, he now
advanced so far in the true path of investigation’; and if the
manner in which heat is diffused in the atmosphere and the
consequent decrease of density were not known when he
wrote, he advanced as far as the existing state of knowledge
enabled him to do. It is certain from his letters, that, after
much time and labour, he at last succeeded in calculating a
table of refractions on the principle that the density is pro-
portional to the pressure. Such a table he communicated to
Flamsteed, although it is not found in the letters lately pub-
lished; and there is every reason to think it the same which
he gave to Halley, and which that astronomer inserted in the

* Newton demonstrates strictly that the densities will be in geometrical
proportion when the distances from the earth’s centre are in musical or
harmonical proportion, that is, when they are the reciprocals of an arith-
metical progression; but in a series of this kind, if the first term bear an
almost infinitely great proportion to the differences of the following terms,
as is the case of the radius of the earth when compared to elevations within
the limits of the atmosphere, the differences of the terms or the elevations
may, without sensible crror, be reckoned in arithmetical progression,

Mr. Ivory on the Theory of the Astronomical Refractions. 345

Philosophical Transactions for 1721. Two elements only are
sufficient for computing all the numbers in a table of refrac-
tions constructed by assuming that the density is proportional
to the pressure, namely, the refraction at 45° of altitude, and
the height of the homogeneous atmosphere, which is deducible
from the horizontal refraction. ‘The table of Halley, there-
fore, contains in itself all that is required for ascertaining
whether it was calculated or not by the principle alluded to
in the letters of Newton to Flamsteed. Kramp seems to be
the first who sought in the table for the manner of its construc-
tion; and his discoveries in this branch of science enabled
him to assign the height of the homogeneous atmosphere,
which is one essential element. The refraction at 45° of
altitude, which is the other element, is found in the table equal
to §4’, or, in parts of the radius, to ‘0002618: and Kramp
found 4377* teises for J, the height of the homogeneous at-
mosphere; so that, if @ be the radius of the earth in toises,
we have

= -0002618,

z=

a
l
—= *0013356;
a

and the two elements, « and 2, are sufficient for computing the
whole table, if it be such as is mentioned in the correspond-
ence between Newton and Flamsteed. The formula for the
refraction in the supposed constitution of the atmosphere has
been given both by Kramp and Laplace ; and it may be taken
from the paper in the Philosophical Transactions for 1823,
p. 441,

1 = = ‘19601, A= Vv cos’ + 2is,

sin 9 1—A x= %) ae
as x {( + 7 ay ih

—2s
Ca A or

Dd dda sti. SSG, 3

8 a3 4dsc—* yA
goe A
the integrations extending from s = 0 tos =. The co-
efficients of this formula are as follows:

»
=
i

* Anal. des Réfractions Astronomiques, p. 19.

346 Mr. Ivory on the Theory of the Astronomical Refractions.

rz r3
2 vee Dae —— = °§2
1 + 7) 6 82193
B =A — 2474+ 22% =°'13423
3 9
— — a? — — 73 =°'02
Cc 5 a 02377
Gale |
1D) = 3 a = ‘02007
For the horizontal refraction, when cos § = 0, A= WV 27s,

we obtain by the usual integrations,

36 = ON og {A+B 2+ Gi Bia Dv«}s
WV 27 }
or in seconds, 86 = 2024-2 instead of 2025” as in Halley’s
table. This proves the exactness of Kramp’s elements.
With respect to the other numbers in the table a distinc-
tion must be made. In every table of refractions, whatever
be the constitution of the atmosphere on which it is founded,
the numbers answering to altitudes greater than 16°, depend
only upon one element, namely, the refractive power of the
air. Reckoning from the zenith as far as 74°, any table may
be deduced from any other, provided both are accurately cal-
culated, merely by a proportion. In the table published an-
nually in the Con. des Temps, the refraction at 45° is 58!"-2:
and, if Halley’s table has been accurately computed, the
numbers in it, between the limits mentioned, will be equal

to the like numbers in the French table multiplied by a

A The calculation being made, the results will be

found to agree almost exactly with the short table inserted
by M. Biot in the additions to the Con. des Temps for 1839,
p. 105, the greatest difference between the computed quan-
tities and the numbers in Halley’s table, being about 2".
But this gives no intimation with respect to the particular
constitution of the atmosphere assumed in the calculation
of the table. What is peculiar to a table in this respect has
no sensible influence on the refractions it contains except at
altitudes less than 16°. No definitive opinion can therefore
be formed on the question, whether Halley’s table is the same
which Newton computed and communicated to Flamsteed on
the principle that the densities are proportional to the press-
ures, without comparing it with a sufficient number of re-

Mr. Ivory onthe Theory of the Astronomical Refractions. 347

fractions at low altitudes calculated from the elements of
Kramp. As the settling of this point may be thought not
unimportant, the following formula, which affords the means
of computing the refractions at all altitudes with exactness,
has been investigated by reducing the integrals in the expres-
sion of 84 to serieses.

2Wv 5t $

e = tan —_-
cost 2

Log tan $¢ = log secant 9 + 19°2133569 — 20.

Tan >=

i log.
84 = sin 8 X e X 660°795 «..... 2°8200669

4+ e x 55LGBA oeveee 2°7337059

+ 6? X 371°268 eeoees 2:5§96873

+ e7 x 219°762 oeseee 2°3419630

+ & x 116°763 «+00 2:0673034

+e! x 58°170 coves 1°7646976

+ 3X 2B°ZT5S covers 1°4.514092

+ ex 13°797 eoeeee 1°1397974

+ ell 6806 wse--. 0°8329041

+ el9 x BBL woes 0°5199046 }
The series converges very slowly, which has made it necessary
to continue it to ten terms, the amount of which is still 3-6
deficient from the exact quantity 9024''-2. As the last terms
decrease in the proportion of 2 to 1, it is obvious that the
true sum would be obtained by continuing the series: but
the terms set down are more than sufficient for the present
purpose.

The exact refractions calculated by the formula are next

to be compared with the numbers in Halley’s table.

Apparent zenith- Refractions
dist.

___ | Difference.
Computed. Halley’s Table.

° Teal onl i

20 19:6 20 —0-4
40 45-2 45 +02
60 1 33-1 1 32 +1:1
70 2 27:0 2 26 +1-0
80 4 55:2 4 52 43-2
82 6 39 6 00 +39
84 7 45:0 7 45 0-0
86 10 53-1 10 48 +51
87 13 22-5 13 20 +25
88 17 46 17 8 —3-4
89 23 3-5 QS 7 —3'5

The examination that has now been made fully establishes

348 Mr. Ivory on the Theory of the Astronomical Refractions.

that Halley’s table is no other than the one which Newton
computed on the supposition that the densities in the atmo-
sphere are proportional to the pressures. The discrepancies,
amounting in every instance to a small part of the whole
quantity, are such as might be expected to occur unavoidably
in the intricate and laborious methods of calculation followed
by Newton. Some part of the differences may also arise from
the elements of the formula, which, being deduced from only
two numbers of the table, may not exactly coincide with the
fundamental quantities which Newton assumed. M. Biot, by
a method different from Kramp’s, has found other elements,
which make the horizontal refraction 8'*3 less than in the
table; but these small variations, which proceed from cal-
culating in different ways, only confirm more strongly that
Halley’s table is the same which Newton constructed by his
second hypothesis, and communicated to Flamsteed.

It appears from what has been said, that, as far as the ma-
thematics is concerned, the problem of the astronomical re-
fractions was fully mastered by Newton. It would be strange
indeed to suppose that the author of the theories in the Prin-
cipia would find difficulty to apply them in a case to which
he bent the whole force of his mind. But he was embar-
rassed by the suppositions he found it necessary to make
respecting the physical constitution of the atmosphere. His
first hypothesis is evidently contrary to nature, in admitting
that air at all altitudes exerts the same power to inflect the
light to the earth’s centre; his second method made the re-
fractions too great near the horizon, thereby proving the ne-
cessity of searching out some new cause for the purpose of
reconciling the theory with observation. Averse from hypo-
theses, he seems, on these accounts, to have declined inserting
in his works a problem which had cost him so much labour,
and upon his solution of which he evidently set some value.

If the different attempts to solve this problem are to be
tried with the same rigour that Newton judged his own, it
must be decided that they are all liable to objections. ‘They
all involve some supposition that has no foundation in nature ;
or they leave out some necessary condition of the problem.
It is allowed that the variation of heat at different altitudes is
unknown; that we are equally unacquainted with the manner
in which is diffused the aqueous vapour that is always found,
more or less, in the atmosphere; that the law of the densities
has not been ascertained. But besides these capital points,
the accurate M. Poisson will suggest other properties that
must be attended to in an atmosphere in equilibrium: the
conducting power of heat varying with the conditicn of the

Mr. Ivory on the Theory of the Astronomical Refractions. 349

air; its power of absorbing heat; and the interchange by ra-
diation which takes place with the earth, with the etherial
spaces above, and with the stars visible above the horizon.
So many conditions, placed beyond the reach of our inquiry,
may well puzzle the most expert algebraist to take them into
account, But it may be doubted whether this be the proper
view of the problem. ‘The astronomical refractions at any
observatory are mean effects of the atmosphere; and it may
be alleged that the proper way of accounting for them is to
compare them with other mean effects of the atmosphere at
the same place.

4. In 1715, twenty years after the researches of Newton,
Brook Taylor published in his Methodus Incrementorum, the
first investigation of the astronomical refractions on the sup-
position that the density of the air is variable. The differ-
ential equation is accurately deduced trom the principles laid
down by Newton; which removed all the difficulties of the
problem in this respect.

Kramp, in his Analyse des Réfractions Astronomiques et
Terrestres, has elucidated the elementary parts of the pro-
blem, and has greatly improved the mathematical solution. His
method is particularly commodious and useful in the case of
the horizontal refraction. For altitudes above the horizon
the integrals are not susceptible of being simply expressed,
and seem to require the aid of subsidiary tables in applying
them.

The problem of the refractions being an important one in
astronomy, many solutions of it have been published by dif-
ferent geometers. Some of these are preferable to others,
because the method of calculation is easier in practice. For
altitudes greater than 16°, they may all be reckoned equiva-
lent, differing from one another only in the quantity assumed
for the refractive power of air. ‘They also mostly agree in
the horizontal refraction, which is taken from observation.
But for altitudes less than 16°, they are different ; because, at
these low altitudes, the refractions are affected by the arbi-
trary suppositions used in constructing the tables.

Thomas Simpson published a judicious dissertation on this
problem. He distinctly points out that, to a considerabte di-
stance from the zenith, the refractions are independent of the
mauner in which the atmosphere is supposed to be consti-
tuted. In comparing the two atmospheres that have densities
decreasing in arithmetical and geometrical progression, he
remarks that the horizontal refraction comes much nearer the
observed quantity in the first atmosphere than it does in the
second; for which reason he gives the preference to the first

350 Mr. Ivory on the Theory of the Astronomical Refractions.

as likely to represent the phzenomena with greater accuracy.
Now in this his reasoning is not much different from the ar-
gument afterwards used by Laplace, to prove that the same
two atmospheres are limits between which the true atmosphere
is contained.

Newton likewise found that the refractions computed ac-
cording to his second method, that is, in an atmosphere with
densities decreasing in geometrical progression, are too great
near the horizon, on which point he thus writes to Flamsteed :
‘* Supposing the atmosphere to be constituted in the manner
described in the 22nd proposition of my second book (which
certainly is the truth), I have found, that if the horizontal
refraction be 34’, the refraction at the altitude of 3° will be
13’ 3!; and if the refraction in the apparent altitude of 3° be
14’, the horizontal refraction will be something more than 37!.
So that instead of increasing the horizontal refraction by va-
pours, we must find some other cause to decrease it. And
I cannot think of any other cause besides the rarefaction of
the lower region by heat.” Here the true reason is assigned
why the refractions near the horizon, in an atmosphere con-
stituted as supposed, so much exceed the observed quantities.
When the density is made to depend solely on the incum-
bent weight, the air is not rarefied enough; and the greater
density causes a greater refraction. Having correctly esti-
mated the effect produced by the pressure of the supported
air, Newton is unavoidably led to ascribe to heat the greater
rarefaction that takes place in the atmosphere of nature. His
words prove that he had no clear conception in what manner
the density in the lower region is altered by the agency of
heat; and, to say the truth, nearly the same ignorance in this
respect prevails now as in his time. The decrease of density
in ascending is a complicated effect of many causes for the
most part unknown; and it seems in vain to expect a satis-
factory investigation of it by arbitrary suppositions. But
setting aside hypothetical constitutions of the atmosphere, we
may consider the rarefaction of the air in ascending as a
phenomenon, the knowledge of which is to be acquired by
experiment; and this appears the only sure way of placing
the theory of the mean refractions on its proper foundation.

5. One of the tables of refraction most esteemed by astro-
nomers is that published annually in the Con. des Temps. It
has been already shown that, as far as 74° from the zenith,
this table is calculated by the simple method of Cassini.
There is nothing incidental in this; for all tables of refraction
may be computed by Cassini’s method to the extent men-
tioned. The French astronomers have been very successful

Mr. Ivory on the Theory of the Astronomical Refractions. 351

in determining the constants of the formula. The refractive
power of the air was obtained by Delambre from a great
number of astronomical observations ; the same quantity was
dedaced by MM. Biot and Arago from experiments on the
gases with the prism; and the results of two methods, so en-
tirely different, agree so nearly, that there seems no ground
for preferring one to the other. The remaining part of the
French table, for altitudes less than 16°, is computed by a
method of Laplace, which the author has explained, with-
out disguising its defects, in the fourth volume of the Méc.
Céleste. "The two atmospheres with densities decreasing in
arithmetical and geometrical progression, which it now ap-
pears were imagined by Newton, and which have been dis-
cussed by Thomas Simpson and other geometers, are found,
when the same elements are employed, to bring out hori-
zontal refractions on opposite sides of the observed quantity.
Laplace conjectured that an intermediate atmosphere which
should partake of the nature of both, and should agree with
observation in the horizontal refraction, would approach
nearly to the true atmosphere. It must be allowed, that these
conditions, which may be verified by innumerable instances
between the two limits, are vaguely defined ; and in order to
ascertain the real meaning of the author, recourse must be
had to the algebraic expressions. When this is done, it will be
found that the atmosphere intended is one of which the den-
sity is the product of two terms, one taken from an arithme-
tical, and the other from a geometrical progression; the ef-
fect of which combination is to introduce a supernumerary
constant, by means of which the horizontal refraction is made
to agree with the true quantity. No one will deny the merit
and the ingenuity of Laplace’s procedure; but though very
skilful, and guided in some degree by fact, it is liable to all
the uncertainty of other arbitrary suppositions, as indeed the
author allows. Dr. Brinkley has given the character of the
French table fairly when he says, that it is only a little less
empirical than the other tables. On divesting Laplace’s hy-
pothesis of vagueness in the language, and expressing it in
the unequivocal symbols of algebra, it does not appear to
possess any superiority over other supposed constitutions of
the atmosphere in leading to a better and less exceptionable
theory; at least the Méc. Céleste has been many years before
the public, during which time not a few geometers have la-
boured on the subject of the refractions ; but no improvement
originating in the speculations peculiar to Laplace has oc-
curred to any of them.

352 Mr. Ivory on the Theory of the Astronomical Refractions.

Having said so much on the theory of the French table, it
may be proper to add a word on its accuracy. If it be com-
pared from 80° to 88° of zenith distance with Bessels ob-
served refractions, there will be found a small error in excess,
continually increasing, and amounting at last to 4”. This
shows that, in combining the two atmospheres, too much
weight has been given to that with a density varying in geo-
metrical progression, in consequence of which the air is not
rarefied enough in the interpolated atmosphere. With re-
spect to the two degrees of altitude next the horizon, no ac-
curate judgement can be formed, for want of observed refrac-
tions that can be depended on.

The astronomical refractions have also occupied the atten-
tion of the astronomer of Kcenigsberg, who has contributed
so largely to the improvement of every part of astronomical
science. For the purpose of representing the observations
of Bradley with all the accuracy possible, Bessel investigated
a table of refractions which appeared in the Fundamenta
Astronomia in 1818. He assumes a theoretical formula; but
as every arbitrary quantity is determined by a careful com-
parison with real observations, what is supposititious may be
considered merely as an instrument of investigation, which is
finally laid aside, leaving the result to rest on the foundation
of fact. He returned to the subject in his Tabula Regiomon-
tane, published in 1830. In this last work he retains only
that part of the table of 1818 which extends to 85° from the
zenith, many corrections being applied from recent observa-
tions made with improved instruments. In order to supply
what is wanting in the new table, Bessel has added a sup-
plemental one containing the refractions at every half degree
for altitudes less than 15°: which supplemental table is inde-
pendent of theory, being deduced from observations alone.
These two tables form together a real table of mean refrac-
tions, independent of all suppositions respecting the constitu -
tion of the atmosphere; and no other similar table of nearly
equal authority is to be found in the astronomy of the present
day. What Bessel has accomplished on the subject of the
refractions is not the least important part of his labours for
the advancement of astronomical science: it is precious to
the practical astronomer ; and it is necessary to the theore-
tical inquirer, for enabling him to confront his speculations
with the phenomena to be accounted for.

[To be continued. |

Cai
od

[ 353]

LV. Remarks on a Note in Prof. Sedgwick and Mr, Mur-
chison’s Communication in the last Number. By Joun Putt-
Lips, Lsq., F.R.S., F.G.S., Professor of Geology in King’s
College.

To R. Taylor, Esq.
My pear Sir, York, April 11, 1839.

N the communication regarding the classification of De-

vonshire strata by Professor Sedgwick and Mr, Murchison

(contained in the last Number of the Philosophical Magazine),

I find my name (p. 257, note) connected with a ‘ promise,’

which it appears to me necessary both to explain and to fulfil

as soon as possible after the pledge which has been unex-
pectedly and publicly given for me. ‘This is the more neces-
sary because the statement alluded to does not express com-
pletely either the error assigned, or the correction prepared.

There is no‘ inaccuracy’ in the acknowledgement engraved
on my geological map, that Devonshire is coloured from
Mr. De la Beche. On the contrary, it is to Mr. De la Beche,
alone, that I am indebted for the means of colouring geolo-
gically Cornwall, Devon, and West Somerset. I have, for
these districts, merely copied the complete map with which he
most kindly furnished me early in the year 1838; nor have I
since applied to any person for information on those parts of
the country.

The acknowledgement on my map is, however, in one re-
spect incomplete; it might have been stated that in colouring
as a part of the Carboniferous System the disputed culm de-
posits of Devonshire, I was following the classification first
proposed by Professor Sedgwick and Mr. Murchison at the
Bristol Meeting of the British Association. This is the cor-
rection, or rather addition, which I have promised to make in
the next edition of my map.

It is perhaps unnecessary to do this, since the brief notices
on my map had no other object than to authenticate the de-
lineation, and the classification in question was perfectly
known to geologists, and secured to the right owners by se-
veral publications of two years earlier date*. It is, however,
possible, as the authors of this very important change in the
systematic distribution of English strata appear to think, that
by my silence concerning their labours an erroneous impres-

* See in particular the Sixth Report (1836) of the British Association,
p- 95, and Atheneum for 1836, p. 611. The latter contains the whole
discussion of the subject at the Bristol Meeting of the Association, with a
section according to the new views there advocated. A working map was

then exhibited by Mr. Murchison, coloured to correspond with the sec-
tion.

Phil. Mag. S. 3. Vol. 14, No. 90, May 1839. 2A

354 Prof. Sedgwick and Mr. Murchison’s Supplementary

sion may have been communicated to persons not well ac-

uainted with the progress of geological investigation, and I
shall gladly embrace the opportunity afforded by a new edi-
tion of my map to supply the omission, and to add my un-
equivocal testimony to the originality and value of the dis-
coveries regarding the sequence of Devonian strata which
heralded the new and remarkable views contained in your

last Number. Iam, my dear Sir, yours, &c.
Joun PHILLIPS.

LVI. Supplementary Remarks on the * Devonian” System of
Rocks. By the Rev. Professor Srpewick, F.R.S., F.G.S.,
and Ropverick Impry Murcuison, Esq. £.R.S. £.G.S.*

WE beg to offer a few additional observations on the classi-
fication of the older rocks of Devon and Cornwall, as
a supplement to our paper in the last Number of this Journal.
In briefly alluding to the geologists who had at different
times suggested, that certain portions of these rocks (in South
Devon) might be the equivalents of the carboniferous lime-
stone or old red sandstone, we inadvertently omitted to state,
that in regard to North Devon, our distinguished leader Mr.
William Smith had long ago represented} the band of red
rocks, which extend along the coast from Combe Martin to
the North Foreland, and thence into the Quantock Hills,
as old red sandstone. At that early period, however, this
author had not the materials for an extension of his first cor-
rect glance: neither the order of superposition, nor the fossils
of the succeeding strata, were then known; and hence, rely-
ing chiefly upon mineral characters, and not upon that great
principle, of identifying strata by their organic remains, by
which he had so successfully eliminated the true order of the
secondary formations, Smith did not succeed in referring any
other part of Devonshire or Cornwall to what we consider
its proper place in the geological series. Thus, we find
him equally classing as old red sandstone,a course of red
rocks which may be traced across a considerable part of
Devonshire, a little south of Bideford, and which we have
shown to be a mass included in the culm or coal measures of
the county. Again, he placed the limestones of Holcombe
Rogus, &c., which we also include in the same carboniferous
tract, as subordinate to the new red sandstone; and in com-
mon with all who preceded or followed him up to the period
when we published our views in 1836, he considered the black

* Communicated by the Authors.
+ Smith’s Geological Map of England and Wales.

ee ae!

Remarks on the * Devonian” System of Rocks. 355

culm measures, and the slates of South Devon and Cornwall,
to be among the oldest transition rocks. Still the first indi-
cations of a more accurate view, as given in his representa-
tion of the North Coast of Devon, is to us a strong proof both
of his boldness and sagacity. Doubtless deceived by mineral
characters, slaty cleavage, and the antique impress of many
parts of this region, he never thought of applying his own
sound principles to Devonshire, still less to the killas and so
called “ primary” rocks of Cornwall. Yet is it entirely
through the application of Smith’s * Strata identified by their
organic remains,” that we have been enabled at Jength to
work out what we believe to be a correct classification of
these rocks, and to place them so much higher in the series
than had ever been contemplated by those who have gone
before us. The imbedded plants and shells, and the strong
analogy of the culm strata of Devonshire to those which we
had studied in Pembrokeshire, coupled with their overlying
position, first led us to venture to assert that so large a por-
tion of this region was truly an equivalent of our ordinary
coal fields: and assuming that our view has been sustained,
we have since shown, upon the same principles of imbedded
fossils and a conformable succession of strata, that all the
rocks which rise from beneath the great culm basin (with
perhaps some slight exceptions), whether slates, killas, lime-
stone or sandstone, form one great natural group (hitherto
called old red sandstone), which occupies the great interval
between the Carboniferous System above, and the Silurian
System below it; each of these three great systems being de-
fined, as we have before explained, by a characteristic series
of organic remains.

We have much pleasure in stating that, since the appear-
ance of our memoir in the last Number of this Journal, the
reading of a paper by the Rev. D. Williams to the Geologi-
cal Society upon the structure of Devonshire, gave rise to a
discussion, during which certain explanations took place which
have happily removed from our minds any tendency to sup-
pose, that our fellow-labourers Mr. De la Beche and Mr.
Williams were unwilling to accord to us the merit (whatever
it may be) of having been the first to propose a great change
in the grouping and classification of the rocks of Devonshire
and Cornwall. We beg, therefore, to say, that Mr. De la
Beche having in a kind and friendly manner read from his
Report the passage quoted below*, and having assured the geo-

* © In 1836, Prof. Sedgwick and Mr. Murchison read a memoir before
the meeting of the British Association held that year at Bristol, in which
2A2

356 Prof. Sedgwick and Mr. Murchison’s Supplementary

logists present, that he meant that passage fully to convey the
meaning, that we were the first persons who proposed, on the
evidence of superposition as well as fossils, that the large tract
of Devon and Cornwall (now represented in his map as
** Carbonaceous Rocks”) should be considered as a distinct
physical group belonging to the Carboniferous System; we
are on our part anxious, not only to state publicly, that we
are satisfied of the entire sincerity of this assurance, but also
to express (as one of us did at the Geological Society) our
deep regret that one or two words were employed in our me-
moir which gave pain to our associate. In short, there does
not now exist the slightest misunderstanding between Mr. De
la Beche and ourselves,

And next in regard to the Rev. D. Williams, to whom
we adverted as putting forth a claim to have been the first
to indicate the existence of a trough in Central Devon, we
find (having been favoured by him with a sight of the ori-
ginal notice which he read at Dublin 1835) that the sole
expression which, according to himself, bears upon the point
is this: ‘ The argillaceous schist reposes immediately on
the granite of Lundy Island, mantling round its south-
eastern angle on the one hand and dipping away towards it
from the granite of Dartmoor on the other.” Mr. Williams
indeed allows, that he did not then even mention the word
** trough,” nor was there, indeed, a single expression in the
short notice which could have led any one to suppose that he
had then discovered, that two-thirds of the large county of
Devon consisted of a great culmiferous basin overlying older
strata, still less that this basin was the equivalent of our coal
fields. For his observations in that and all his subsequent
memoirs (even that just read) go to maintain, that these culm
strata are of an age quite distinct from the Carboniferous
era, and form an integral part of the transition series of a
much older epoch.

But in asserting the priority and independence of our own
views, and in pointing out how much. they differ from those
which Mr. De la Beche, Mr. Williams, or indeed any geolo-
gists had previously entertained, we are bound to state, that

they separated the upper mass of rocks of North Devon which had hitherto
been termed grauwacke from the lower, stated that these rocks rested in
a trough-like cavity extending east and west, and concluded that they had
been improperly classed with the lower series, inasmuch as they consi-
dered these rocks to be equivalent to the beds usually termed coal-measures.
The inferior rocks they divided into five subordinate groups.”’ In the
same page Mr. De la Beche also states the substance of our subsequent
paper (1837) read before the Geological Society (See Report, p. 43.).

Remarks on the ** Devonian” System of Rocks. 357

we believe the observations of Mr. Williams to be also equally
original; for he has recently shown to us a MS. which he
sent to the Local Secretaries of the meeting of the British
Association for the Advancement of Science, held at Bristol
(which arrived after the memoir by ourselves was read, and
on that account was not brought forward), in which he ex-
presses his opinion that the contorted carbonaceous rocks
upon the coast between North Devon and Cornwall, occupy
a trough supported at either extremity on the west coast, by
rocks of older age; the whole, however, belonging to an
ancient transition period, and the culm strata being of “ far
higher antiquity than the carboniferous series proper.” And we
may further remark, that at that time he had neither separated
(as a distinct formation) the black culmiferous limestone from
the inferior courses of limestone of North Devon, nor ascer-
tained the fact of its re-appearance on the south side of the
culm trough and on the northern flank of Dartmoor. From
an inspection of the map of Devonshire which Mr. Williams
is preparing, and the sections which were exhibited with it at
the Geological Society, we are convinced he is an industrious
observer; while the richness of his fossil collections also
manifests his diligence and zeal: his collections are, indeed,
among the most valuable (in respect to North Devon and
Cornwall) which have come under our notice; and their ex-
amination, to which he has cordially invited us, has been a
source of much gratification, as it offers a strong confirma-
tion of our opinion of the age of the Devonian and Cornish
strata.

There is now, therefore, no longer any strife concerning
the structure of this region: a generous rivalry alone exists
to bring to the cominon stock of knowledge all the proofs by
which the true age of these hitherto anomalous strata can be
determined. In fact, the order of superposition of the region
is completely settled, for the principal sections of Mr. De
Ja Beche and Mr. Williams are xow in accordance with
our own, in presenting the same succession of mineral masses ;
and it only remains that we should enter into a hearty union
to determine the precise coordinates of these masses by a
thorough examination of their imbedded organic remains.

We have already stated in the previous notice, and we have
sincere pleasure in repeating it, that we owe deep obligations
to our friend Mr. Lonsdale for having first suggested to us
that the Devon fossils would be found to be those of the old
red system; a point which he was admirably qualified to de-
termine from having compared so closely the fossils (particu-
larly the corals) of the Carboniferous and Silurian Systems,

358 The Rev. D. Williams on the Geology of Devonshire.

If therefore, as we now believe, (together with Mr.Lonsdale
and Mr. James Sowerby) that these peculiar fossils constitute
the links which connect the Carboniferous and Silurian Sy-
stems, we have only to produce clear evidences; and this
done, we venture to assert, that however indisposed a priori,
to admit the necessity of so great and sweeping a re-
form, there is no lover of truth (and all true geologists are
such) who will not participate in the conviction, that as a few
important pages in the early history of the earth have been
unfolded for the first time in Devonshire, we are entitled to
suggest that the “ Devonian System” be henceforth a term
admitted into our geological nomenclature.

P.S. In addition to what we have written in this Journal,
we have prepared for reading before the Geological Society,
a short exposé of our present views concerning the structure
of Devon and Cornwall, accompanied by. a geological map of
the West of England and Wales, which illustrates the amount
of change proposed in this new classification. It is also our
intention to visit in the course of this summer those districts
of France (Britany, &c.) in which the existence of transition
coal fields has been maintained, as we deem it highly proba-
ble, that the application of the same principles which have
enabled us to classify the rocks of Devon and Cornwall, may
be successfully employed in that region of France which seems
to be physically connected with the country in question.

April 19, 1839.

LVII. On the Classification of certain Geological Formations
in Devonshire. By the Rev. Daviy Wiiu1AMs, F£.G.S.

To the Editors of the Philosophical Magazine and Journal.
GENTLEMEN,
EELING assured that Prof. Sedgwick and Mr. Murchison

will do me justice with respect to as much of the article
in your last Number which implicates me more seriously
than any one else, I trouble you only with a few remarks on
the hypothesis of Mr. Lonsdale, which they have reanimated
and quickened by a new sanction and impulse. Much I ap-
prehend will depend on future observations before it can with
justice be received or rejected. I always believed the plant and
culm-bearing rocks to belong to the upper grauwacke ; and
if the carboniferous champions will only modify their views
a little, and include the whole in their old red sandstone
group, I know of no difficulty at present to my adopting the
theory; but I must unlearn a great deal before I admit the

Royal Society. 359

carbonaceous limestones and fossiliferous rocks and culm of
Devon and Cornwall to be true coordinates of the upper great
coal-field and its carboniferous limestone. Ata late meeting of
the Geological Society, I endeavoured to show that these
black limestones, containing Goniatites, Posidoniz, &c. were
in their eastward extension, viz. at Holcomb Rogus, Chud-
leigh and Ashburton, overlaid by the gray coralline limestones
of those places, and I entertain no doubt that the greater part
of their zoophytous reliquize will be shown not to appertain
to the mountain limestone. All the prominent phenomena
of the county tend to show that we are here first ascending
within the carboniferous influence, or perhaps attaining the
rudimentary efforts of nature at a coal deposit. The downward
tendency of the coal in the North of England below the car-
boniferous limestone, as shown by Professor Sedgwick, and
among the old red sandstone in Scotland, as shown by Mr.
Murchison, encourages me somewhat in being the bearer of
this flag of truce. If the sum of evidence adduced hereafter
should prove these culmiferous limestones not to be an
equivalent for the mountain limestone, why they must be be-
low it; and the mountain limestone, millstone grit, and the
upper great coal-field are not represented here at all, inas-
much as the Devonshire culm measures are inseparably asso-
ciated with their limestones and subordinate slate rocks, by
an indisputable transition and a perfect conformity of strike
and dip. The base line of the carboniferous system would
thus be placed at a lower level as suggested by Prof. Sedg-
wick at Liverpool, and the correctness of Mr. De la Beche’s
original views of the grauwacke age of the plants and culm
admitted. I remain, Gentlemen, yours, &c.

Bleadon W. Cross, April 24, 1839. D. Witt1aMs.

LVIII. Proceedings of Learned Societies.

ROYAL SOCIETY.
Feb. 14, A Paper was read, entitled, “‘ Researches on the Chemical
1839. Equivalents of certain Bodies.” By Richard Phillips,
Esq., F.R.S.

The author examines, by a new series of experiments, the truth
of the theory of Dr. Prout and Dr. Thomson, namely, that ‘‘ all
atomic weights are simple multiples of that of hydrogen,” a theory
which the late Dr. Turner had maintained is at variance with the
most exact analytic researches, and consequently untenable. Although
the experiments of Dr. Turner, and the inferences which he drew
from them, agree very nearly with those of Berzelius, it still ap-
peared to the author desirable to investigate this subject; and it

360 Royal Society.

occurred to him that the inquiry might be conducted in a mode not
liable to some of the objections which might be urged against the
processes usually employed.

Dr. Turner having adopted a whole number, namely 108, as the
equivalent of silver, this substance was selected by the author as the
basis of his inquiry into the equivalent numbers of chlorine, and
some other elementary gases. It appeared to him that the chance
of error arising from the fusing of the chloride of silver might be
entirely removed, and other advantages gained, by experimenting on
silver on a large scale, with such proportions of the substances em-
ployed as were deemed to be equivalents ; and instead of calculating
from the whole product of the fused chloride, to do it merely from
the weight of such small portion only, as might arise from the dif-
ference between theoretical views and experimental results.

The author concludes, from the train of reasoning he applies to
the series of experiments so undertaken, that no material, and even
scarcely any appreciable error can arise from considering the equiva-
lent numbers of hydrogen, oxygen, azote, and chlorine, as being 1,
8, 14, and 36 respectively.

A paper was also read, entitled, ‘‘ Some Account of the Hurricane
of the 7th of January, 1839, as it was experienced in the neighbour-
hood of Dumfries,” in a letter addressed to P. M. Roget, M.D. Se-
cretary to the Royal Society. By P. Garden, Esq. Communicated
by Dr. Roget.

After describing the position of his house, and the nature of the
instruments employed for observation, the writer gives his observa-
tions of the barometer and thermometer on the 6th and 7th of Ja-
nuary last, and proceeds to state, that on the 6th, at about ten
minutes past ten o’clock p.m. violent squalls commenced, at first
with intermissions of perfect calms, but gradually becoming more
frequent, and being accompanied by the sound of strong and in-
creasing whirlwinds. By eleven o’clock the wind was observed to
proceed from the East, and its velocity was estimated at forty miles
an hour. Its violence then increased, and threatened to blow down
the chimneys. At midnight it abated, at the same time shifting to
the south or west. At two o’clock in the morning nearly two tons
of lead were torn away by the wind from the west end platform on
the house-top, and thrown down behind the house in a westerly di-
rection. Some of the lower windows having been left alittle open,
the wind thus admitted into the house forced up and blew off the
very heavy hatch-door of the roof, which was covered with lead.
The whole house rocked terribly, and even the stone floor of the
half-sunk kitchen story heaved as if shaken by an earthquake: the
slates from the roof were blown in every direction, some being car-
ried to a prodigious distance. During the greater part of the night
the rain fell in tremendous torrents. In the interval from two to
half-past three in the morning, the barometer sunk very nearly an
inch and a half, and reached its greatest depression. But the tem-
pest continued till about four o’clock, when it began gradually to
subside. Extensive devastation occurred among the trees ; some that

Royal Society. 361

were blown down raising two or three tons of clay soil with the roots.
Several trees thus thrown down fell with their tops to the W.N.W.

The writer concludes from these and other observations, that the
first and squally part of the storm began from the E.S.E., and blew
from S. by W. at about midnight; and that most injury was done
to the slating and roof when the wind was not far from the south. It
then gradually veered to the west, till noon, and reached the N.W.
point by eight o’clock in the evening of the same day.

Feb. 21.—A paper was read, entitled, ‘‘ An Account of the Pro-
cesses employed in Photogenic Drawing,” in a letter to S. Hunter
Christie, Esq., Sec. R.S. By H. Fox Talbot, Esq., F.R.S.*

A paper was also read, entitled, ‘“‘ A Description of a Hydro-
pneumatic Baroscope.” By J.T. Cooper, Esq., Lecturer on Che-
mistry.

The liability of the ordinary mercurial barometer to derangement
and to fracture, led the author to the construction of an instrument
for measuring atmospheric pressure that should be exempt from
these objections. It consists of a float, formed by a brass tube,
having the shape of the frustum of an inverted cone, nine inches
long, two inches in diameter above, and one inch below, and its
content being about fourteen cubic inches. From the centre of the
upper and wider end, which is closed, a brass wire proceeds, sur-
mounted by a cup, for the purpose of holding such weights as are
necessary for bringing the float, when immersed in water, to the
same constant level. The lower and smaller end of the tube is
closed by a brass plug, sufficiently heavy to sink the instrument to the
proper depth, and maintain its position, and having a small perfora-
tion in its centre. This float is inclosed in a case, containing the
water in which it is to be immersed, and which is to be raised to a
constant given temperature by a spirit lamp burning beneath it.
The float being first filled with water, a given portion of this water
is poured out into a measure of known capacity, and is consequently
replaced by an equal volume of air, the dilatations or contractions of
which will, when the temperature is constant, be dependent only on
the external pressure of the atmosphere ; and the latter will, there-
fore, be indicated by the weights requisite to be placed in the cup of
the float, in order to maintain it at the same level in the fluid, on the
principle of the hydrometer. The author gives a minute description
of all the parts of the apparatus, of the method of using it, and of
the adjustments and calculations required for determining by its
means the difference of level of two stations.

Mr. Darwin’s paper, entitled, ‘‘On the Parallel Roads of Glen
Roy, and other parts of Lochaber, &c.,” was resumed, but not con-
cluded.

Feb. 28.—The reading of a paper, entitled, “‘ Observations on the
Parallel Roads of Glen Roy, and of other parts of Lochaber, with an
attempt to prove that they are of Marine Origin.” By Charles Dar-

* This paper was given entire in our Number for March ; pres. vol. p.
209.—Epir.

362 Royal Society.

win, Esq., M.A., F.R.S., Sec. Geological Society, was resumed and
concluded.

The author premises a brief description of the parallel roads,
shelves, or lines, as they have been indefinitely called, which are
most conspicuous in Glen Roy and the neighbouring valleys, re-
ferring for more detailed accounts to those given by Sir Thomas
Lauder Dick, in the Transactions of the Royal Society of Edin-
burgh, and by Dr. Macculloch in those of the Geological Society of
London. Both these geologists endeavour to explain the formation
of these shelves on the hypothesis of their resulting from depositions
at the margin of lakes, which had formerly existed at those levels,
The author, however, shows that this hypothesis is inadmissible,
from the insuperable difficulties opposed to any conceivable mode of
the construction and removal, at successive periods, of several bar-
riers of immense size, whether placed at the mouths of the separate
glens, or at more distant points. He does not, however, propose
the alternative, that the beaches, if not deposited by lakes, must of
necessity have been formed by channels of the sea, because he deems
it more satisfactory to prove, from independent phenomena, that a
sheet of water, gradually subsiding from the height of the upper
shelves to the present level of the sea, occupied for long periods not
only the glens of Lochaber, but the greater number, if not all the
valleys of that part of Scotland; and that this water must have been
that of the sea. Itis argued by the author, that the fluctuating ele-
ment must have been the land, from the ascertained fact of the land
rising in one part, and at the same time sinking in another; and
therefore, that this change of level in Scotland, attested as it is by
marine remains being found at considerable heights both on the
eastern and western coasts, implies the elevation of the land, and
not the subsidence of the surrounding waters. The author next
shows, that in all prolonged upward movements of this kind, it might
be predicted, both from the analogy of volcanic action, and from
the occurrence of lines of escarpment rising one above the other
in certain regions, that in the action of the subterranean im-
pulses there would be intervals of rest. On the hypothesis that the
land was subjected to these conditions, it appears that its surface
would have been modeled in a manner exactly similar, even in its
minute details, to the existing structure of the valleys in Lochaber.
Considering that he has thus established his theory, the author pro-
ceeds to remove the objections which might be urged against its
truth, derived from the non-extension of the shelves, and the ab-
sence of organic remains at great altitudes, He then shows how
various details respecting the structure of the glens of Lochaber,
such as the extent of corrosion of the solid rock, the quantity of
shingle, the numerous levels at which water must have remained,
the forms of the heads of the valley, where the streams divide, and
especially their relation with the shelves, and the succession of ter-
races near the mouth of Glen Spean, are all explicable on the suppo-
sition that the valleys had become occupied by arms of a sea which
had been subject to tides, and which had gradually subsided during

aed Te

Royal Society. 363

the rising of the land; two conditions which could not be fulfilled in
any lake. From the attentive consideration bestowed by the au-
thor on these several and independent steps of the argument, he re-
gards the truth of the theory of the marine origin of the parallel roads
of Lochaber (a theory, of which the foundation stone may be said to
have been laid by the important geological researches of Mr. Lyell,
establishing the fact of continents having slowly emerged from be-
neath the sea) as being sufficiently demonstrated.

The author states, in the concluding part of his paper, the follow-
ing as being the chief points which receive illustration from the
examination of the district of Lochaber by Sir Thomas Lauder Dick,
Dr. Macculloch, and himself. It appears that nearly the whole of
the water-worn materials in the valleys of this part of Scotland were
left, as they now exist, by the slowly retiring waters of the sea;
and the principal action of the rivers since that period has been to
remove such deposits ; and when this had been effected, to excavate
a wall-sided gorge in the solid rock. Throughout this entire district,
every main, and most of the lesser inequalities of surface are due,
primarily to the elevating forces, and, secondarily, to the modeling
power of successive beach-lines. The ordinary alluvial action has
been. exceedingly insignificant ; and even moderately sized streams
have worn much less deeply into the solid rock than might have
been anticipated, during the vast period which must have elapsed
since the sea was on a level with the upper shelves: even the steep
slopes of turf over large spaces, and the bare surface of certain rocks,
having been perfectly preserved during the same lapse of time. The
elevation of this part of Scotland to the amount of at least 1278 feet
was extremely gradual, and was interrupted by long intervals of
rest. It took place either during the so called ‘ erratic block pe-
riod,” or afterwards; and it is probable that the erratic blocks were
transported during the quiet formation of the shelves. One of these
was found at an altitude of 2200 feet above the present level of the
sea. ‘The most extraordinary fact is, that a large tract of country
was elevated to a great height, so equably, that the ancient beach-
lines retain the same curvature, or nearly so, which they had when
forming the margin of the convex surface of the ancient waters.
The inferences drawn by the author from these facts, and which he
corroborates by other evidence, are that a large area must have been
uplifted, and that its rise was effected by a slight change in the
convex form of the fluid matter on which the crust of the earth rests ;
and therefore that the fluidity of the former is sufficiently perfect to
allow of the atoms moving in obedience to the law of gravitation,
and consequently, of the operation of that law modified by the cen-
trifugal force: and lastly, that even the disturbing forces do not
tend to give to the earth a figure widely different from that of a
spheroid in equilibrium.

March 7.—A paper was read, entitled, ‘‘Onthe Male Organs of
some of the Cartilaginous Fishes.” By John Davy, M.D., F.R.S.,
Assistant Inspector of Army Hospitals.

In this paper, which is wholly occupied with anatomical details,

364 Royal Society.

the author refers to his paper on the Torpedo, which was published
in the Philosophical Transactions for 1834; and also to Miiller’s
work ‘“‘De Glandularum secernentium structura penitiori,”” whose
descriptions and views are not in accordance with those given in
that paper. In the present memoir he adduces evidence of the ac-
curacy of his former statement, chiefly founded on microscopical ob-
servations, and offers some conjectures respecting the functions of
several organs found in cartilaginous fishes; but does not pretend
to attach undue importance to his speculations.

A paper was also read, entitled, ‘‘ Researches in Physical Geo-
logy.—Third Series. On the Phenomena of Precession and Nuta-
tion, assuming the interior of the earth to be a heterogeneous fluid.”
By W. Hopkins, Esq., M.A., F.R.S., &c.

Having, in his last memoir, completed the investigation of the
amount of precession and nutation, on the hypothesis of the earth’s
consisting of a homogeneous fluid mass, contained in a homogeneous
solid shell, the author here extends the inquiry to the case in which
both the interior fluid and external shell are considered as hetero-
geneous. After giving the details of his analytical investigation, he
remarks, that he commenced the inquiry in the expectation that the
solution of this problem would lead to results different from those
previously obtained on the hypothesis of the earth’s entire solidity.
This expectation was founded on the great difference existing be-
tween the direct action of a force on asolid, and that on a fluid mass,
in its tendency to produce a rotatory motion; for, in fact, the dis-
turbing forces of the sun and moon do not tend to produce directly
any motion in the interior fluid, in which the rotatory motion causing
precession and nutation is produced indirectly by the effect of the
same forces on the position of the solid shell. A modification is thus
produced in the effects of the centrifugal force, which exactly com-
pensates for the want of any direct effect from the action of the dis-
turbing forces; acompensation which the author considers as scarcely
less curious than many others already recognized in the solar system,
and by which, amidst many conflicting causes, its harmony and per-
manence are so beautifully and wonderfully preserved.

The solution of the problem obtained by the author destroys the
force of an argument, which might have been urged against the hy-
pothesis of central fluidity, founded on the presumed improbability
of our being able to account for the phenomena of precession and
nutation on this hypothesis, as satisfactorily as on that of internal
solidity. ‘The object, however, of physical researches of this kind
is not merely to determine the actual state of the globe, but also to
trace its past history through that succession of ages, in which the
matter composing it has probably passed gradually through all the
stages between a simple elementary state and that in which it has
become adapted to the habitation of man. In this point of view the
author conceives the problem he proposes is not without value, as
demonstrating an important fact in the history of the earth, pre-
suming its solidification to have begun at the surface; namely, the
permanence of the inclination of its axis of rotation, from the epoch

————

Sir J. F. W. Herschel on the Art of Photography. 365

of the first formation of an exterior crust. This permanence has
frequently been insisted on, and is highly important as connected
with the speculations of the author on the causes of that change of
temperature which has probably taken place in the higher latitudes :
all previous proofs of this fact having rested on the assumption of
the earth’s entire solidity; an assumption which, whatever may be
the actual state of our planet, can never be admitted as applicable
to it at all past epochs of time, at which it may have been the habi-
tation of animate beings.

The author concludes, by expressing a hope that he may be enabled
to prosecute the inquiry still further, and to bring before the Royal
Society, at a future time, the matured results of his speculations.

March 14.—A paper was read, entitled, ‘‘ An Experimental In-
quiry into the Formation of Alkaline and Earthy Bodies, with re-
ference to their presence in Plants, the Influence of Carbonic Acid
in their generation, and the equilibrium of this gas in the atmo-
sphere.” By Robert Rigg, Esq. Communicated by the Rey. J.
B. Reade, M,A., F.R.S.

The object of the author, in the present memoir, is to show that
the solid materials which compose the residual matter in the analy-
sis of vegetable substances, and which consist of alkaline and earthy
bodies, are actually formed during the process of fermentation, whe-
ther that process be excited artificially, by the addition of a small
quantity of yeast to fermentable mixtures, or take place naturally
in the course of vegetation, or of spontaneous decomposition. His
experiments also tend to show that this formation of alkaline and
earthy bodies is always preceded by the absorption of carbonic acid,
whether that acid be naturally formed or artificially supplied. He
finds, also, that different kinds of garden mould, some being calca-
reous, others siliceous, and others aluminous, exposed in retorts to
atmospheres consisting of a mixture of carbonic acid gas and com-
mon air, absorb large quantities of the former, combining with it
in such a manner as not to afford any traces of this carbonic acid
being disengaged by the action of other acids. He considers the
result of this combination to be the formation of an alkaline body,
and also of a colouring matter. This combination takes place to a
greater extent during the night than during the day ; and in gene-
ral, the absorption of carbonic acid by the soil is greatest in pro-
portion as it is more abundantly produced by the processes of vege-
tation ; and conversely, it is least at the time when plants decom-
pose this gas, appropriating its basis to the purposes of their own
system. Hence he conceives that there is established in nature a
remarkable compensating provision, which regulates the quantity of
carbonic acid in the atmosphere, and renders its proportion constant.

A paper was also read, entitled, ‘‘ Note on the Art of Photogra-
phy, or the application of the Chemical Rays of Light to the pur-
poses of Pictorial Representation.” By Sir John F. W. Herschel,
Bart., K.H., V.P.R.S., &c.

The author states that his attention was first called to the subject
of M, Daguerre’s concealed photographic processes, by a note from

366 Royal Society.

Captain Beaufort, dated the 22nd of January last, at which time he
was ignorant that it had been considered by Mr. Talbot, or by any
one in this country. As an enigma to be solved, a variety of pro-
cesses at once presented themselves, of which the most promising
are the following; Ist, the so-called de-oxidizing power of the che-
mical rays in their action on recently precipitated chloride of silver;
2ndly, the instant and copious precipitation of a mixture of a solu-
tion of muriate of platina and lime-water by solar light, forming an
insoluble compound, which might afterwards be blackened bya va-
riety of agents; 3rdly, the reduction of gold in contact with de-
oxidizing agents; and, 4thly, the decomposition of an argentine
compound soluble in water, exposed to light in an atmosphere of
peroxide of chlorine, either pure or dilated.

Confining his attention, in the present notice, to the employment
of chloride of silver, the author inquires into the methods by which
the blackened traces can be preserved, which may be effected, he
observes, by the application of any liquid capable of dissolving and
washing off the unchanged chloride, but of leaving the reduced, or
oxide of silver, untouched. These conditions are best fulfilled by
the liquid hyposulphites. Pure water will fix the photograph, by
washing out the nitrate of silver, but the tint of the picture result-
ing is brick-red; but the black colour may be restored by washing
it over with a weak solution of hyposulphite of ammonia.

The author found that paper impregnated with the chloride of
silver was only slightly susceptible to the influence of light: but an
accidental observation led him to the discovery of other salts of silver,
in which the acid being more volatile, adheres to the base by a weak
affinity, and which impart much greater sensibility to the paper
on which they are applied; such as the carbonate, the nitrate, and
the acetate. The nitrate requires to be perfectly neutral; for the
least excess of acid lowers in a remarkable degree its susceptibility.

In the application of photographic processes to the copying of
engravings or drawings, many precautions, and minute attention to
a number of apparently trivial, but really important circumstances,
are required to ensure success. In the first tranfers, both light and
shadow, as well as right and left, are the reverse of the original :
and to operate a second transfer, or by a double inversion to repro-
duce the original effect, is a matter of infinitely greater difficulty ;
and in which the author has only recently ascertained the cause of
former failures, and the remedy to be applied.

It was during the prosecution of these experiments that the au-
thor was led to notice some remarkable facts relating to the action
of the chemical rays. He ascertained that, contrary to the prevail-
ing opinion, the chemical action of light is by no means proportional
to the quantity of violet rays transmitted, or even to the general
tendency of the tint to the violet end of the spectrum: and his ex-
periments lead to the conclusion that, in the same manner as media
have been ascertained to have relations sui generis to the calorific
rays, not regulated by their relations to the rays of illumination and
of colour, they have also specific relations to the chemical spectrum,

Royal Society. 567

different from those they bear to the other kinds of spectra. For
the successful prosecution of this curious investigation, the first step
must consist in the minute examination of the chemical actions of
all the parts of a pure spectrum, not formed by material prisms,
and he points out, for that purpose, one formed in Fraunhofer’s me-
thod, by the interference of the rays of light themselves in passing
through gratings, and fixed by the heliostat.

He notices a curious phenomenon respecting the action of light
on nitrated paper ; namely, its great increase of intensity, under a
certain kind of glass strongly pressed in contact with it ; an effect
which cannot be explained either by the reflection of light, or the
presence of moisture ; but which may possibly be dependent on the
evolution of heat.

Twenty-three specimens of photographs, made by Sir John Her-
schel, accompany this paper: one, a sketch of his telescope at
Slough, fixed from its image in a lens ; and the rest copies of engra-
vings and drawings, some reverse, or first transfers ; and others se-
cond transfers or re-reversed pictures.

March 21.—The following papers were read :—

I. “Description of a Compensating Barometer, adapted to Me-
teorological purposes, and requiring no corrections either for Zero,
or for Temperature.” By Samuel B. Howlett, Esq., Chief Military
Draftsman, Ordnance. Communicated by Sir John F. W. Herschel,
Bart., K.H., V.P.R.S., &c.

In the instrument here described, there is provided, in addition to
the ordinary barometric tube (inverted, in the usual way, in a cistern
of mercury,) a second tube of the same dimensions, placed by the
side of the former, and likewise filled with mercury, but only to the
height of twenty-eight inches above the level of the mercury of the
cistern. This tube is closed at its lower end, and fixed to a float
supported by the mercury in the cistern: and it bears, at its upper
end, an ivory scale, three inches in length. The elevation of the
mercury in the barometric tube is estimated by the difference be-
tween its level and that of the mercury in the closed tube ; and is
measured on the ivory scale by the aid of a horizontal index, em-
bracing both the tubes, and sliding vertically along them. As the
float which bears the closed tube, to which the scale is attached,
rests freely on the mercury in the cistern, and consequently always
adjusts itself to the level of that fluid, no correction for the zero
point is needed; and as every change of temperature must similarly
affect the columns of mercury in both the tubes, after the scale has
been adjusted so as to read correctly at any given temperature, such
as 32°, which may be effected by comparison with a standard baro-
meter, every other reading will correspond to the same temperature,
and will require no correction. The author considers the error
arising from the difference of expansion corresponding to the dif-
ferent lengths of the two columns of mercury, and which will rarely
amount to one four-hundredth of an inch, as too small to deserve
attention in practice, being, in fact, far within the limits of error in
ordinary observations. J

368 Royal Society.

Subjoined to the above paper is a letter from the author to Sir
John Herschel, containing a statement of comparative observations_
made with a mountain barometer, and with the compensation baro-
meter, from which it appears that the use of the latter is attended
with the saving of a great quantity of troublesome calculation. The
comparative observations are given in a table, exhibiting a range of
differences from +°012 to —:016 of an inch.

II. «An Account of the fall of a Meteoric Stone in the Cold
Bokkeveld, Cape of Good Hope.” By Thomas Maclear, Esq,
F.R.S., &c., inaletter to Sir John F. W. Herschel, Bart., V.P.R.S.,
and communicated by him.

The appearance attending the fall of this aerolite, which happen-
ed at half-past nine o’clock in the morning of the 13th of October,
1838, was that of a meteor of a silvery hue, traversing the atmo-
sphere, for a distance of about sixty miles, and then exploding with
a loud noise, like that from artillery, which was heard over an area
of more than seventy miles in diameter; the air at the time being
calm and sultry. The fragments were widely dispersed; and were
at first so soft as to admit of being cut with a knife; but they after-
wards spontaneously hardened. The entire mass of the aerolite is
estimated at about five cubic feet.*

III. “‘ Chemical Account of the Cold Bokkeveld Meteoric Stone.”
By Michael Faraday, Esq., D.C.L., F.R.S., &c., ina letter to Sir John
F. W. Herschel, Bart., V.P.R.S., &c., and communicated by him.

The stone is stated as being soft, porous, and hygrometric ; having
when dry, the specific gravity of 2°94; and possessing a very small
degree of magnetic power irregularly dispersed through it. One
hundred parts of the stone, inits natural state, was found to consist
of the following constituents ; namely,

Waters. We (betta 6°5 Aluminatiny. tnaeeeoee,
PSE) oT Saas eae APS i MMIC. Yoo chats abel 1-64
Ue Mert soley aes: oust 28°9 Oxide of Nickel. . *82
Protoxide of Iron.... 33°22 OxideofChromium +7
Magnesia... ..2...: 19-2 Cobalt and Soda.. a trace.

IV. ‘ Note respecting a new kind of Sensitive Paper.” By Henry
Fox Talbot, Esq., F.R.S.

The method of preparing the paper here referred to consists in
washing it over with nitrate of silver, then with bromide of potas-
sium, and afterwards again with nitrate of silver; drying it at the
fire after each operation. This paper is very sensitive to the light
of the clouds, and even to the feeblest daylight.

The author supplies an omission in his former memoir on photo-
genic drawing, by mentioning a method he had invented and prac-
tised nearly five years ago, of imitating etchings on copper plate, by
smearing over a sheet of glass with a solution of resin in turpentine,
and blackening it by the smoke of a candle. On this blackened sur-
face a design is made with the point of a needle, the lines of which

* Some further information respecting this fall of meteorites will be

found in the Intelligence and Miscellaneous Articles in the present Num-
ber, p. 391.—E. W. B.

ee“ a= =>

Linnean Society. 369

will of course be transparent, and will be represented by dark lines
on the prepared paper to which it is applied, when exposed to sun-
shine. he same principle may be applied to make numerous copies
of any writing.

The Society then adjourned over the Easter Recess, to meet again
on the 11th of April. ——

LINNZAN SOCIETY.

March 6, 1838.—Mr. Newman, F.L.S., exhibited specimens of
the Noctua cubicularis in the larva state, obtained from Ham Green,
near Bristol, the seat of Richard Bright, Esq., where this caterpillar
had proved very destructive to wheat in the rick.

Dr. Bromfield, F.L.S., exhibited a specimen of a singular variety
of Crepis virens, with the leaves nearly entire, gathered by him in a
wood near Yarmouth in the Isle of Wight.

A plant in flower of the rare Ophrys lutea of Cavaniilas was ex-
hibited by Mr. Anderson, from the Apothecaries’ Garden at Chelsea.

Read a description of the Mosses collected in the journey of the
late deputation into Upper Assam, in the years 1835 and 1836. By
William Griffith, Esq., Assistant Surgeon on the Madras Establish-
ment. Communicated by R. H. Solly, Esq., F.R.S. & LS.

March 20, 1838.—Read a description of the Mora tree. By Mr.
Robert H. Schomburgk. Communicated by George Bentham, Esq.,
F.L:S.

April 3, 1838.—Read a communication on the existence of Sto-
mata in Mosses. In a letter to R. H. Solly, Esq., F.R.S. & L.S.
By William Valentine, Esq., F.L.S.

Mr. Anderson, F.L.S., exhibited, from the Chelsea Botanic Gar-
den, flowering plants of Pterostylis concinna and Perdicium lyratum.

April 17, 1838.—Read a paper by Prof. Don, Libr. L.S., de-
scribing two new genera of the natural family of plants called Coni-

ere.

May 1, 1838.—Mr. Curtis read a paper, being descriptions of the
Coleoptera collected by Capt. P. P. King, R.N., during his survey
of the Straits of Magellan.

Read a paper on the affinities of Arachis and Voandzeia. By
George Bentham, Esq., F.L.S.

May 24, 1838.—This day, the anniversary of the birth-day of
Linnzus, and that appointed in the charter for the election of Coun-
cil and Officers, the Right Kev. the Bishop of Norwich, President of
the Society, opened the business of the meeting, and in stating the
number of Fellows whom the Society had lost during the past year,
gave biographical notices of some of them.

At the election which subsequently took place, the Lord Bishop
of Norwich was re-elected President; Edward Forster, Esq., Trea-
surer; Francis Boott, M.D., Secretary; and Richard Taylor, Esq.,
Under Secretary. ‘The following five gentlemen were clected into
the Council in the room of others going out: viz. Arthur Aikin,
Esq.; John Jos. Bennett, Esq. ; George Bentham, Esq. ; the Earl of
Derby; and John Guillemard, Esq.

Phil. Mag. 8. 3. Vol. 14. No. 90. May, 1829. 2B

370 Geological Society.

June 5, 1838.—Read observations on the Spongilla fluviatilis.
By John Hogg, Esq., M.A., F.L.S.

Read also a paper, entitled, on the Number and Structure of the
Mammule employed by Spiders in the process of Spinning. By
John Blackwall, Esq., F.L.S.

Mr. Saunders, F.L.S., presented specimens of Potamogeton planta-
gineus and Mendicago denticulata, var. apiculata, gathered in Sussex.

Mr. Hogg, F.L.S., exhibited specimens of Plumatella repens and
Spongilla fluviatilis from a rivulet near Norton in the county of Dur-
ham. One of the Spongille was attached to the larva-case of Phry-
ganea, and another to a tuft of Hypnum riparium, which it had en-
tirely enveloped.

June 19, 1838.—Specimens of the tree which yields the Caout-
chouc or India Rubber of Commerce, and which proves to be a spe-
cies of Hevea, nearly related to the guianensis of Aublet, were pre-
sented by Sir Everard Home, Bart., Capt. R.N.

Read a Description of a new species of Cattleya. By Mr. Robert
H. Schomburgk. Communicated by the Secretary.

Read likewise observations on some genera of Plants connected
with the Flora of Guiana. By George Bentham, Esq., F.L.S.

Noy. 6, 1838.—Read a letter from Mr. Jonathan Couch, F.L.S.,
giving an account of a single specimen of Wilson’s Petrel (Procel-
laria Wilsoni) having been found dead in a field near Polperro in
Cornwall, about the middle of August last, at a time when the
Stormy Petrel (P. pelagica) abounded on the coast, most probably
driven thither by the state of the weather at that period.

Read also Observations on the Cause of Ergot. By Mr. John
Smith, A.L.S.

The Chairman announced to the Meeting that the late Nathaniel
John Winch, Esq., of Newcastle-upon-Tyne, had bequeathed to the
Society his entire Herbarium, consisting of upwards of 12,000 spe-
cies of plants, together with his library of Natural History.

November 20, 1838.—Read the Description of a new Genus of
Plants belonging to the Natural Family Bignoniacee. By Professor
Don, Libr. L.S.

There was also read an account of a new species of Lepidosperma.
By Dr. John Lhotsky.

GEOLOGICAL SOCIETY.

Feb. 6.—A paper “ On a probable Cause of certain Earth-
quakes,” by M. Louis Albert Necker, For. Mem. G. S., was read.

The object of this memoir is to show, that some earthquakes may
be due to the falling in of the roof of cavities, produced by the sol-
vent or erosive powers of subterranean bodies of water on beds
and masses of gypsum, rock salt, limestone, marl, clay or sand.

M. Necker was induced to enter upon the inquiry in conse-
quence of the earthquake which desolated, in 1829, a considerable
part of the country on the banks of the Segura, in Murcia, having
occurred in a district, which is stated to contain no volcanic or trap-
pean rocks; and because the event was unaccompanied by any of

eo

Geological Society. $71

those phenomena which, he conceives, precede, attend, or follow
true volcanic earthquakes.

Of the places where earthquakes have been felt without there
being any traces of volcanic or trap rocks, but where gypsum is
known to occur, and in which, from that mineral being, in his opi-
nion, of comparatively easy renewal, he supposes, caverns exist, M.
Necker more particularly mentions Bale, Nice, Navarroux, Oleron,
Maulen, Bagnorre de Bigorre, and the Gave Maulen, in the Py-
renees ; he also alludes to the shocks which were felt at Clanssaye,
near St. Paul-trois-Chateaux, in the department of the Drome,
from the lst of June, 1772, to the end of December, 1773, and he
states, that though Clanssaye stands upon a tertiary deposit, yet
it is probable that the gypseous formation of the hills to the east-
wards having a westerly dip may pass beneath it: likewise to the
earthquakes which affected Kronstadt in T ransylvania, Odessa,
Bucharest, Lembourg in Gallicia, and Kieff, with other towns in that
part of Russia, early in 1838, and in the vicinity of which gypsum
is believed to exist. Among the limestone tracts, in which caverns
abound, and earthquakes are not unfrequently felt, M. Necker enu-
merates Fiume, Buchari, Trieste, Lissa in the Adriatic, and Fo-
ligno.

In the above instances M. Necker supposes, that cavities having
been formed by the action of bodies of water, the roof gave way,
and, falling upon a solid floor, produced in the strata a motion
which extended laterally and vertically, and gave rise to the pheno-
menon of an earthquake. He is further of opinion, that air con-
fined in the caverns being also set in motion by the subsidence of the
roof, would cause undulations in the overlying strata. To illustrate
his views, M. Necker described the vibrations produced in the walls
of a house which he occasionally inhabits at Geneva, by the blows
of a blacksmith’s hammer upon an anvil placed in a vault, and
these vibrations always appeared to him completely analogous to
the motion which he experienced in the same room during the earth-
quake on the 19th of February, 1812. He likewise stated, that M.
Virlet perceived, in a coal-mine, a shock resembling that of an
earthquake, by the falling in of some works at the distance of
a quarter of a league.

With respect to the shocks felt at Nice, the author says, that he
had carefully compared the list published by M. Risso, with the ac-

_ counts of eruptions of Vesuvius and Etna; and that though some

of the earthquakes had preceded, by very short intervals, certain
powerful eruptions of those volcanoes; yet, in very many
instances, the shocks appear to have been quite independent ; and
that a considerable number of eruptions, both of Vesuvius and
Etna, had not been felt at Nice. Hence, he infers, that, in this case,
there may have been earthquakes due to volcanic, as well as non-
volcanic, agents; and that Nice, standing upon a gypsum forma-
tion, may have felt the effects of volcanic eruptions in consequence
of a predisposition in the undermined ground, without which they
would not have been perceptible at the surface.
2B2

372 Geological Society.

M. Necker objects to the earthquake in Calabria, in 1783, being
considered of true volcanic origin, because it was unaccompanied by
any disengagement of heat, lava, smoke, acid, or sulphureous pro-
ducts; because the surface of the ground was depressed, not ele-
vated ; because only sand and water were ejected through the fis-
sures and circular or star-like cavities formed in the ground, and be-
cause there was no eruption of Vesuvius or Etna. The earthquakes
in the valley of the Mississippi, during 1812, he conceives were
non-volcanic, in consequence of no lava having been poured forth,
nor any acid or other vapours emitted. He alluded to a letter by
Mr. Stanley Griswold, dated Kaskahia, Illinois, the 22nd of Dec.
1812, which describes some of the phenomena of the earthquakes,—
particularly the subterranean noises resembling thunder, the cracks
formed in the ground, the issuing of ‘‘ a something”’ like smoke, or
warm aqueous vapour, accompanied by a great quantity of sand,
the ejection of carbonised wood, coal, and pumice, a quantity of
which is said to have been collected on the Mississippi, the drying
up of lakes, and the raising of the bed of the river. To some of
these statements M. Necker objects. He conceives that the smoke,
or warm aqueous vapour, which is mentioned only from the reports
of others, and not decidedly, may have been mistaken for vapour
produced by water striking against an immoveable obstacle. The
occurrence of pumice, he conceives, is very doubtful; and, as it is
mentioned by no other author, he withholds his assent till the sub-
stance has been examined by a competent mineralogist.

M. Necker dissents from the Cutch earthquake in June, 1819,
being considered volcanic. The elevation of the Ullah Bund, he
conceives, was effected by the subsidence of the ground towards
Sindree, or to a movement on a fixed axis. The materials thrown
out by the shocks were only black mud, sand, wrought iron, and
nails, and could not therefore, he says, have been produced from
any great depth.

The earthquakes on the coast of Cumana, and the Caraccas, M.
Necker considers to be non-yolcanic ; and that when the number and
violence of the shocks felt in that part of America are considered, he
is of opinion, that the agreement of the earthquakes, in April, 1812,
with the simultaneous eruption of the volcano of St. Vincent, was
purely fortuitous.

In 1772, the little group, situated some leagues to the north of
the chain of the Caucasus, and composed of the trachytic moun-
tains called Pechstein, and the calcareous hill Metschuka, was
shaken by an earthquake. The warm springs, known by the name
of the baths of the Caucasus, issue from the foot of the limestone
hill, and deposit, as well as all the cold brooks, considerable quanti-
ties of calcareous tuff. It might be supposed, observes M. Necker,
that the thermal springs indicate the existence of some portion of
the original heat of the trachyte ; and that the earthquake of 1772,
by which a portion of the hill, Metschuka, was engulphed, was only
the effect of volcanic activity. This, he says, is possible; but it ap-
pears to him much more probable, that the cold and warm springs

ce eB

Geological Society. 373

had formed large cavities in the limestone hill, the falling in of the
roof of which produced the shock and attending phenomena.

The earthquakes in Jamaica in 1692, M. Necker is of opinion
were non-volcanic, because there were only subsidences of the
ground, and because only water, sand, and gravel were ejected.

The earthquake in the plain of Bogota, 16th November, 1827, he
is tempted to consider non-volcanic, the country being gypsiferous
and saliferous; but he admits that it may have been of a mixed
nature, in consequence of the great adjacent volcano of Popa-
yan being, at the same time, in activity. The earthquakes on the
coast of Chili, he is of opinion, may have a similar origin.

M. Necker gives a list of earthquakes extracted from Mr. Lyell’s
« Principles of Geology,” and arranges them under the heads—vol-
canic, non-voleanic, and of doubtful origin.

In the first list he includes the earthquakes felt at Ischia,
February 2nd, 1828; Java, 1699, 1772, and 1786; Sumbana, April,
1815; Quito, Feb. 4, 1797; Sicily, March, 1693, 1790; Guati-
mala, 1773; Kamtschatka, 1737; Peru, Oct. 28, 1746; Iceland,
1725; Teneriffe, May 5, 1706; Sorea, (Moluccas) 1693; Lisbon,
Nov. 1, 1755.

Non-Volcanic.—Murcia, 1829; Lahore, Sept. 1827 ; Lissa, in the
Adriatic, 1833; Foligno, Jan. 15, 1832; Cutch, June 16, 1819;
Cumana, Dec. 14, 1797; the Caraccas, March 26, 1790; Calabria,
1783 to 1786; Bechstan, 1772 ; and Jamaica, 1692.

Doubtful Origin. —Bogota, Nov. 16, 1827; Chili; Quebec, Dec.
1791; Nipon, Japan, August 1, 1783; and Martinique, 1772.

Thus, though M. Necker reduces considerably the power of vol-
canic agents, yet he is far from denying that a weak volcanic move-
ment may be propagated over considerable surfaces; and he men-
tions, in conclusion, the following instances, as not generally known,
of probable connexions between earthquakes and volcanic eruptions.
The great eruption of Vesuvius, which commenced the 21st of Fe-
bruary, 1822, was preceded by an earthquake at Geneva, and in the
province of Bugey, in France, on the 19th of February ; and, before
the eruption of October of the same year, the environs of Aleppo, in
Syria, had been convulsed during the whole of August; the most
violent shocks having taken place the 13th of the same month ; and
on the 14th of August an earthquake was experienced at Laybach
in Carniola. On the 19th of February, 1825, the town of St.
Maure, in the Ionian Islands, was almost destroyed by an earth-
quake, felt also at Corfu and Prevesa. During the night of the
20th and 21st of February, 1825, there were several shocks at San
Veit in Carinthia; and on the 21st of February, and for five days
after, dreadful earthquakes were felt at Alger and its environs. The
25th of February, 1828, Vesuvius, which had been very quiet from
1822, commenced a new eruption. ‘There were earthquakes at
Trieste during the night of the 13th and 14th January, 1828, at the
Island of Ischia on the 2nd of February, and all over Belgium the
23rd of the same month. Lastly, M. Necker deems it not impro-
bable, that the earthquakes felt in Hungary, Transylvania, Gallicia,

374 - Geological Society :— Anniversary of 1839.

Wallachia, and the south of Russia, at the commencement of 1838,
were the precursors of the eruptions of Vesuvius and Etna during
the summer of the same year.

ANNUAL GENERAL MEETING, Feb. 15, 1839.

The President announced that the Wollaston Medal and £20
had been awarded by the Council to Professor Ehrenberg of Berlin,
for his discoveries respecting Fossil Infusoria; and in delivering the
Medal with the accompanying sum of money into the hands of the
Chevalier Bunsen, who was present, Mr. Whewell addressed him as
follows :

Mr. Bunsen,

I have great pleasure in delivering into your hands the Wollas-
ton Medal, which the Council of this Society have awarded to your
countryman Professor Ehrenberg, for his discoveries respecting Fos-
sil Infusoria. These discoveries, eminently striking and curious to
all intelligent persons, are full of the most lively interest for Geolo-
gists. Such discoveries area just reward of M. Ehrenberg’s merits,
since he had prepared himself for this success by a profound study
of natural history, by persevering and scrutinizing researches, and by
extensive and enterprising travels. We gladly give this medal asa
proof that we sympathize in the admiration which these discoveries
have excited throughout scientific Europe.

To many others, and to myself in particular, there is an additional
source of pleasure at having such a communication to make to M.
Ehrenberg, in the circumstance of our having recently become ac-
quainted with him, and having seen personally in our own country
the evidences of his talents and genius, his simple and strenuous
love of knowledge. We beg you to communicate to him with this
medal the expression of our admiration in his labours, our deep inter-
est in their results, and our warm wishes that he may long have
granted him the health and energy and opportunity which their suc-
cessful prosecution demands.

Allow me to say also, that we trust that this token of our respect
will be kindly received by M. Ehrenberg’s countrymen as well as by
himself, and that they will accept it as a testimony how gladly we
do honour to the profound knowledge and patient research which
distinguish that great branch of the European family. I rejoice to
be able to deliver this medal into the hands of a distinguished coun-
tryman of Professor Ehrenberg; and I cannot but add, as an addi-
tional ground of satisfaction, into the hands of one, who, by his wide
acquaintance with men of science and learning, and with their works,
is so well prepared to sympathise with their honours and successes,
as he is by his nature prompted to rejoice in excellence of every
kind.

The Chevalier Bunsen acknowledged the distinction conferred
upon Professor Ehrenberg in the following terms :—

Sir,—I feel highly gratified by the honour conferred upon me, of
receiving at your hands the valued acknowledgement of the merits
of my distinguished countryman, Professor Ehrenberg, and I beg to

~ eeeeee

——

Award of the Wollaston Medal to Prof. Ehrenberg. 375

return thanks, not only in my name, but also in that of Baron Bu-
low, as the representative of Prussia in this country, who is prevented
by official business from being present on this occasion.

Nobody can be more able or inclined to appreciate duly the value
of this distinction than Professor Ehrenberg. I know from himself
that it was by England in particular that he wished his researches
to be examined and approved ; and it was especially by this illustrious
Society, so worthily presided over by one whose name is also in Ger-
many equally dear to the friends of religion and moral philosophy,
and to the followers of the exact sciences: it was to this Society, I
say, to whose tribunal he was desirous to submit the judgement of
the merits and importance of his discovery. Indeed, the honour
you have decreed him to-day is only the public confirmation and so-
lemn badge of that kind and encouraging interest which he met with
from the members of this Society, and for which he felt the most
sincere gratitude.

But this feeling, Sir, will not be confined to himself: the honour
of the prize awarded to him this day amongst so many illustrious
competitors of all nations, will be deeply felt by the whole literary
public of Germany : it will, I trust, form a new link in that intel-
lectual union between the two great and enlightened nations, which
have so many ties of common interest, and so many objects of warm
and deep sympathy ; an union which must become every day more
and more intimate, and prove productive of the most beneficial con-
sequences, not only for the progress of science in the whole range
of human intellect, but for the welfare of humanity at large.

The flattering manner in which you have been pleased to allude
to myself obliges me to say a few words on my own behalf. I feel
only too much how entirely I must attribute those expressions to
the kindness that inspired them, knowing how inadequate my own
merits are to deserve them. But I rejoice sincerely at having this
opportunity offered to me, publicly to express my feelings of grati-
tude for the kind and generous reception I have constantly met with
in this country, which for so many years and for so many and good
reasons, has been the object of my love and of my admiration—feel-
ings which will ever remain engraven on my heart, and with a par-
ticularly gratifying reference to this day.

The following gentlemen were elected the Officers and Council
for the ensuing year :

President.—Rev. W. Buckland, D.D., Professor of Geology and
Mineralogy in the University of Oxford. Vice-Presidents.—G. B.
Greenough, Esq. F.R.S. & L.S.; Leonard Horner, Esq. F.R.S.
L. & E.; Charles Lyell, jun. Esq. F.R.S. & L.S.; Rev. Adam Sedg-
wick, F.R.S. & L.S., Woodwardian Professor in the University of
Cambridge. Secretaries. —Charles Darwin, Esq. F.R.S.; William
John Hamilton, Esq. Foreign Secretary.—H. T. De la Beche, Esq.
F.R.S. & L.S. Treasurer.—John Taylor, Esq. F.R.S. Council.—
Professor Daubeny, M.D. F.R.S. & L.S.; Sir P. Grey Egerton, Bart.
M.P. F.R.S.; W. H. Fitton, M.D. F.R.S. & L.S.; Prof. Grant,
M.D. F.R.S.; Rev. Prof. Henslow, F.L.S.; W. Hopkins, Esq.

376 Geological Society.

M.A. F.R.S.; Robert Hutton, Esq. M.P. M.R.I.A.; Sir Charles
Lemon, Bart. M.P. F.R.S.; Prof. Miller, M.A.; R. I. Murchison,
Esq. F.R.S. & L.S.; Richard Owen, Esq. F.R.S.; Sir Woodbine
Parish, K.C.H. F. R. S.; George Rennie, Esq. F. RS. ; Rev. Prof.
Whewell, F.R.S.

Address delivered by the Rev. Witt1am WueEwe tt, B.D. F.R.S.
President.
GENTLEMEN,

The Reports which have been read show that the Society is still
in a state of progression as to numbers, although in consequence of
some oversights in preceding periods, the comparison of this year’s
statement with that of last year 28 not at first sight give an accu-
rate view of our progress.

I venture also to speak of our pecuniary condition as prosperous,
although, in the Estimates for the present year the expenses exceed
the income. This excess admits of explanation: the estimated ex-
penses include the cost of publishing a Part of our Transactions,
and as this occurs only about once in two years, the whole expense
ought not to be considered as belonging to one year. Stoves and
other articles of furniture, expenses not likely to recur, have also
inflamed the debtor side of our account.

There is one considerable article in our estimated expenses, of
which payment may not be required, but from which I confess I
should be sorry to see the Society liberated. I speak of the salary
of our Curator. In my address last year I stated that the Council
had it in contemplation to make some arrangement by which Mr.
Lonsdale’s labours, then far too heavy, should be lightened. This
was done, I believe to the satisfaction of every one, by separating
the office of Curator from that of Assistant Secretary, and tothe former
office Mr. Wood was appointed, with asalary of 125/. The Council
found in Mr. Wood’s zeal and knowledge every reason to congratulate
themselves on the possession of such an officer; and have heard with
regret that the state of his health compels him to resign his office. I
trust, however, that the Council will be able to provide some means
of rendering the Society’s Collection useful, without allowing Mr.
Lonsdale to be again burthened with a complication of duties inju-
rious to him and inconvenient to the Society.

Although, as I have said, I look without any inquietude upon the
state of our funds, it is impossible not to allow that such an aspect
of them makes it necessary to attend to economy wherever it is
possible. There is one part of our establishment to which I am com-
pelled, most reluctantly, to apply this remark; I mean, our Library
and Museum. I fear that we must consider ourselves as under
the necessity of confining within very narrow limits any assistance
which can be rendered to those departments from our general funds.
And yet we cannot look at these paris of our establishment, and
especially at the Library, without seeing that they do in fact re-
quire very material additions. Our Library, which ought to possess
all the best books and maps which bear upon our science, is desti-

Biihreiins ee

elit SA Saat poh

—— aa =_—-_-

Anniversary of 1839. Address of the President. 377

tute of many of them, especially of the more modern works, to an
extent which we should hardly any of us find tolerable in our
private libraries. This deficiency interferes materially with the
utility of the Society, and is indeed inconsistent with its character.
We shall, I trust, all agree that it is a state of things we ought to
remedy. At no period of the history of this body has there been
found wanting, when the occasion demanded it, a liberal and gene-
rous spirit among its members; and I am fully persuaded that at
the present day the love of the Society has not waxed cold among
the Fellows, nor have their purse-strings become rigid. It has ap-
peared to me, that when a definite list of our deficiencies is laid
before you, it will not be found difficult for each person to find in
such a list some article, book or map, which it will gratify him that
the Society should possess as his gift. In this or in some other
way I do not doubt that we shall be able to bring up the condition
of our Library to that which the time and our position require.
The Council have adjudged the Wollaston medal for the present
year to Professor Ehrenberg, for his discoveries respecting fossil In-
fusoria and other microscopic objects contained in the materials of
the earth’s strata. We all recollect the astonishment with which,
nearly three years ago, we received the assertion, that large masses
of rock, and even whole strata, are composed of the remains of mi-
croscopic animals. This assertion, made at that time by Professor
Ehrenberg, has now not only been fully confirmed and very greatly
extended by him, but it has assumed the character of one of the
most important and striking geological truths which have been
brought to light in our time: for the connection of the present
state of the earth with its condition at former periods of its history,
a problem now always present to the mind of the philosophical
geologist, receives new and unexpected illustration from these re-
searches. Of about eighty species of fossil Infusoria which have
been discovered in various strata, almost the half are species which
still exist in the waters: and thus these forms of life, so long over-
looked as invisible specks of brute matter, have a constancy and
durability through the revolutions of the earth’s surface which is
denied to animals of a more conspicuous size and organization.
Again, we are so accustomed to receive new confirmations of our
well-established geological doctrines, that the occurrence of such an
event produces in us little surprise; but if this were not so, we could
not avoid being struck with one feature of Prof. Ehrenberg’s dis-
coveries ;—that while the microscopic contents of the more recent
strata are all freshwater Infusoria, those of the chalk are bodies
( Peridinium, Xaunthidium, Fucoides,) which must, or at least can,
live in the waters of the ocean. Nor has Prof. Ehrenberg been con-
tent with examining the rocks in which these objects occur. During
the last two years he has been pursuing a highly interesting series
of researches with the view of ascertaining in what manner these
vast masses of minute animals can have been accumulated. And
the result of his inquiries is*, that these creatures exist at present in

* Abhandl. Kon, Ak. Wissensch. Berlin. 1838.

378 Geological Society.

such abundance, under favourable circumstances, that the difficulty
disappears. In the Public Garden at Berlin he found that workmen
were employed for several days in removing in wheelbarrows masses
which consisted entirely of fossil Infusoria. He produced from the
living animals, in masses so large as to be expressed in pounds, tri-
poli and polishing slate similar to the rocks from which he had ori-
ginally obtained the remains of such animals; and he declares that
a small rise in the price of tripoli would make it worth while to
manufacture it from the living animals as an article of commerce.
These results are only curious; but his speculations, founded upon
these and similar facts, with respect to the formation of such rocks,
for example, polishing slate, the siliceous paste called hezselguhr, and
the layers of flint in chalk, are replete with geological instruction.
As the discoveries of Prof. Ehrenberg are thus full of interest for
the geological speculator, so have they been the result, not of any
fortunate chance, but of great attainments, knowledge, and labour.
The author of them had made that most obscure and difficult portion
of natural history, the infusorial animals, his study for many years ;
had travelled to the shores of the Mediterranean and the Red Sea
in order to observe them; and had published (in conjunction with
Prof. Miiller) a work far eclipsing anything which had previously
appeared upon the subject. It was in consequence of his being
thus prepared, that when his attention was called to the subject of
fossil Infusoria, (which was done in June, 1836, by M. Fischer) he
was able to produce, not loose analogies and insecure conjectures,
but a clear determination of many species, many of them already
familiar to him, although hardly ever seen perhaps by any other eye.
The animals (for he has proved them to be animals, and not, as others
had deemed them, plants) consist, in the greater number of examples,
of a staff-like siliceous case, with a number of transverse markings ;
and these cases appear in many instances to make up vast masses by
mere accumulation without any change. Whole rocks are composed
of these minute cuirasses of crystal heaped together. Prof. Ehren-
berg himself has examined the microscopic products of fifteen locali-
ties, and is still employed in extending his researches; and we already
see researches of the same kind undertaken by others, to such an
extent, as to show us that this new path of investigation will exercise
a powerful influence upon the pursuits of geologists. We are sure
therefore that we have acted in a manner suitable to the wishes
of the honoured Donor of the medal, and to the interests of the
science which we all in common seek to promote, in assigning the
Wollaston medal to Prof. Ehrenberg for these discoveries.
Although it is not necessary as a ground for this adjudication, it
is only justice to Prof. Ehrenberg to remark, that his services to
geology are not confined to the researches which I have mentioned.
His observations, made in the Red Sea, upon the growth of corals,
are of great value and interest; and he was one of the distinguished
band of scientific explorers who accompanied Baron von Humboldt
in his expedition to the Ural Mountains. And I may further add,
that even since the Council adjudged this medal, Prof. Ehrenberg

Anniversary of 1839. Address of the President. 379

has announced to the Royal Academy of Sciences of Berlin new
discoveries ; particularly his observations on the organic structure
of chalk; on the freshwater Infusoria found near Newcastle and
Edinburgh, and on the marine animalcules observed near Dublin
and Gravesend; and, what cannot but give rise to curious reflections,
an account of meteoric paper which fell from the sky in Courland in
1686, and was found to be composed of Conferve and Infusoria.

I now proceed to notice some of the most conspicuous names,
both among our own countrymen and foreigners, which have been
removed by death from our lists since last year.

In Sir Abraham Hume the Society has lost a member who was at
all times one of its most strenuous friends and most liberal supporters,
and especially in its earliest periods, when such aid was of most
value. Indeed he may in a peculiar manner be considered as one
of the Founders of the Society. English geology, as is well known,
evolved itself out of the cultivation of mineralogy,—a study which
was in no small degree promoted, at one time, by the fame of the
mineralogical collections of Sir Abraham Hume and others. The
Count de Bournon, exiled by the French revolution in 1790, brought
to England new and striking views of crystallography, resembling
those which Haiiy was unfolding in France ; and was employed to
arrange and describe the mineralogical collections of Sir John St.
Aubyn and Mr. Greville, and especially the collection of diamonds
of Sir Abraham Hume, of which a description, illustrated with
plates, was published in 1816. Some years before this period a few
lovers of mineralogy met at stated times at the house of Dr. Babing-
ton, whose influence in preparing the way for the formation of this
Society was mentioned with just acknowledgement in the Pre-
sident’s Address, in 1834, by Mr. Greenough ; and certainly he,
more fitly perhaps than any other person, could speak of the merits
and services of his fellow-labourers. Of the number of these Sir
Abraham Hume was one; although not, I believe, one of those who
showed their zeal for the pursuits which associated them by holding
their meetings at the hour of seven in the morning, the only time of
the day which Dr. Babington’s professional engagements allowed
him to devote to social enjoyments of this nature.

Out of the meetings to which I refer this Society more imme-
diately sprung. The connection of mineralogy with geology is
somewhat of the nature of that of the nurse with the healthy child
born to rank and fortune. The foster-mother, without being even
connected by any close natural relationship with her charge, sup-
plies it nutriment in its earliest years, and supports it in its first
infantine steps ; but is destined, it may be, to be afterwards left in
comparative obscurity by the growth and progress of her vigorous
nursling. Yet though geology now seeks more various and savoury
food from other quarters, she can never cease to look back with
regard and gratitude to the lap in which she first sat, and the hands
that supplied her early wants. And our warm acknowledgments
must on all due occasions be paid to those who zealously cultivated
mineralogy, when geology, as we now understand the term, hardly
existed; and who, when the nobler and more expansive science

380 Geological Society.

came before them, freely and gladly transferred to that their zeal
and their munificence.

The spirit which prevailed in the infancy of this Society, and to
which the Society owed its permanent existence, was one which did
not shrink from difficulties and sacrifices; and among the persons
who were animated by this spirit Sir Abraham Hume was eminent ;
his purse and his exertions being always at the service of the body.
He gave his labours also to the Society by taking the office of Vice-
President, which he discharged with diligence from 1809 to 1813.
He died in March last at the great age of ninety, being then the
oldest person both in this and in the Royal Society.

Mr. Benjamin Bevan was a civil engineer, and throughout his life
showed a great love of science, and considerable power of promo-
ting its purposes. He instituted various researches, theoretical and
practical, on the strength of materials*; and it was he who first
proved by experiment the curious proposition, that the Modulus of
Elasticity of water and of ice is the same. In 1821 he wrote a
letter to the secretary of this Society, recommending that the form
of the surface of this country should be determined by barometri-
cal measurements of the heights of a great number of points in it,—
the barometer which was to be used as a standard being kept in
London. Mr. Bevan and Mr. Webster were commissioned to pro-
cure a barometer, and Dr. Wollaston recommended one of Carey’s
barometers, but it does not appear that any further steps were
taken. I may remark that recent researches have further con-
firmed the wisdom of Mr. Bevan’s suggestion, that heights should
be measured, as all other measurements are made, from some fixed
conventional standard, instead of incurring the vagueness and in-
consistency which result from assuming the existence of a natural
standard, such as the level of the sea.

Nathaniel John Winch was born at Hampton Court in the year
1769, and after a voyage into the Mediterranean, and travels in
various countries in Europe, settled at Newcastle-upon-Tyne as a
merchant. He had early paid great attention to botany, which he
continued to cultivate during a long life, and kept up a correspond-
ence with all the leading botanists in Europe. He was one of the
earliest, and always one of the most active members of the Literary
and Philosophical Society of Newcastle; and, in conjunction with
a few of his friends, gave to that town a scientific and cultured cha-
racter, which still distinguishes it. He was one of the honorary
members of this Society; and contributed to its meetings, in 1814,
“ Observations on the Geology of Northumberland and Durham,”
and in 1816, “ Observations on the Eastern Part of Yorkshire,” +

* To Mr. Bevan our Journal is indebted for many valuable communi-
cations.—Eb.

+ Besides these papers, Mr. Winch published : ‘‘ The Botanist’s Guide
through the Counties of Northumberland and Durham. By N. J. Winch,
J. Thornhill, and R. Waugh.”’ 2 vols. 1805.—‘ Flora of Northumberland
and Durham.” In the Transactions of the Newcastle Natural History
Society, vol. 2.—*‘ An Essay on the Geographical Distribution of Plants
through the Counties of Northumberland, Durham, and Cumberland.”

Anniversary of 1839. Address of the President. 381

which were printed in the fourth and fifth volumes of our Trans-
actions. In these he stated his object to be to combine with his own
observations much interesting information on the subjects of the
quarries, and coal and lead mines, of those districts, which had long
been accumulating, and was widely diffused among the professional
conductors of the mines. And these memoirs, though not contain-
ing inuch of originality in their views and researches, were, at the
time, of considerable utility. He died May 5th, 1838, and, by his
will, left to this Society a very considerable and valuable mineralo-
gical collection, now in our Museum.

Mr. William Salmond, of York, was one of the persons who was
most zealously and actively engaged in the examination of the cele-
brated Kirkdale Cavern. He measured and explored new branches
of the cave in addition to those first opened, and made large collec-
tions of the teeth and bones, from which he sent specimens to the
Royal Institution of London, and to Cuvier at Paris. The bulk of
his collection was deposited in the Philosophical Society at York,
then newly established.

1 now proceed to notice our deceased Foreign Members.

Francois-Dominique de Reynaud, Comte de Montlosier, was born
at Clermont in Auvergne, April the 16th, 1755, the year of the ce-
lebrated earthquake of Lisbon. He was the youngest of twelve
children of a family of the smaller nobility of that province, and was
remarkable at an early age for the zeal with which he pursued va-
rious branches of science and literature.

Count Montlosier must ever be considered as one of the most
striking writers in that great controversy respecting the origin of ba-
_ saltic rocks, which occupied the attention of mineralogists during the

latter half of the last century ; and to which, in so large a degree, the
progress and present state of geology are to be ascribed. The theory
of the extinct voleanos of Auvergne, the subject of his researches,
was the speculation which gave the main impulse to scientific curi-
osity on this point. It is true that he was not the originator of the
opinions which he so ably expounded. Guettard, in 1751, had seen,
vaguely and imperfectly, that which it now appears so impossible
not to see, the evidences of igneous origin in the rocks of that di-
strict: and the elder Desmarest, whose examination of them began
in 1763, had made that classification of them, which is the basis, and
indeed the main substance, of the views still entertained with regard
to the structure of that most instructive region. His map of the
district, published in 1774 (in the Transactions of the Academy of
Paris for 1771, according to a bad habit of that body still prevail-
ing), exhibits the distinction of modern currents of lava, ancient
currents, and rocks fused in the places where they now are, which
distinction supplies a key to the most extraordinary phenomena,
while it reveals to us a history more wonderful still. But striking
and persuasive as this view was, and fitted, apparently, to carry

First edition, 1820; second edition, 1825.—*‘ Contributions to the Flora
of Cumberland.” 1833.—“ Addenda to the Flora of Northumberland and
Durham.” 1836.

382 Geological Society.

with it universal conviction, the theory which it implied, collected,
as it seemed at the time, from one or two obscure spots in Europe,
was for a while resisted and almost borne down by the opposite
doctrine of the aqueous origin of basalt ; which came from the school
of Freyberg, recommended by the power of a connected and com-
prehensive system,—a power in science so mighty for good and for
evil. Montlosier’s Essay on the Volcanos of Auvergne, which ap-
peared first in 1788, was, however, not written with any direct
reference to this controversy, but was rather the exposition of the
clear and lively views of an acute and sagacious man, writing from
the fullness of a perfect acquaintance with the country which he
described, in which, indeed, his own estate and abode lay. In its
main scheme, although Desmarest’s is mentioned with just praise*,
the object of this Essay is to criticise and correct a work of M.
Le Grand d’Aussy, entitled Voyage en Auvergne. But as the main
additions to sound theory which this work contains, (a point which
here concerns us far more than its occasion and temporary effect)
we may, I think, note the mode in which he traces in detail the
effects which the more recent currents of lava (those which fol-
low the causes of the existing valleys) must have produced upon
the courses of rivers and the position of lakes ; and the idea, at that
time a very bold and, I believe, a novel one, that lofty insulated
ridges and pinnacles of basalt, which tower over the valleys, have
been cut into their present form by the long-continued action of
fluviatile waters, aided by a configuration of the surface very dif-
ferent from the present. The striking and vivid pictures which
Montlosier draws of such occurrences, are to the present day sin-
gularly instructing and convincing to those who look at that region
with the geologist’s eye. After publishing this essay, M. Montlosier, ~
a man of varied and commanding talents, became involved in the po-
litical struggles of his time, and was an active member of the National
Assembly, to which he was sent as Deputy of the Noblesse of Au-
vergne. In his place there he resisted in vain the proposals for the
spoliation of the clergy ; and one speech of his on this subject was
very celebrated. After witnessing some of the changes which his
unhappy country had then to suffer, he became an exile, and resided
in London, where for some years he was the editor of the Courier
Francais, a royalist journal. Under the empire, he returned to
France, and was employed in the Foreign Office of the Ministry, but
recovered little of his property except a portion of a mountain, which
was too ungrateful a soil to find another purchaser. The situation
however could not but be congenial to his geological feelings ; for
his habitation was in the extinct crater of the Puys de Vaches.
The traveller, in approaching the door of the philosopher of Ran-
dane, had to wade through scorie and ashes; and from the deep
basin in which his house stood, a torrent of lava, still rugged and
covered with cinders, has poured down the valley, and at the distance

* After mentioning Guettard, he says, ‘‘ Les mémoires de M. Desmarest,
publiés quelques années aprés, entrainérent tout-a-fait Vopinion pub-
lique.” (p. 20.)

Anniversary of 1839. Address of the President. 383

of a league, has formed a dike and barred up the waters which form
the lake of Aidat ;—a spot celebrated by Sidonius Apollinaris, Bishop
of Clermont in the fifth century, as the seat of his own beautiful
residence, under the name of Avitacus. It is curious to remark that
Sidonius does not overlook the resemblance between his own moun-
tain and Vesuvius:
«* ®mula Baiano tolluntur culmina cono,
Parque cothurnato vertice fulget apex.”

In this most appropriate abode M. de Montlosier was, in his old
age, visited at different times by several distinguished English geolo-
gists, some of whom are now present ; and invariably delighted them
with his unfading interest in the geology of his own region, his hospi-
table reception, and I may add, his lofty and vigorous presence, ac-
cording well with his frank and chivalrous demeanour. His ardour
of character had shown itseif in early age: “ From my first youth,”
thus his Essay opens, “I occupied myself with the natural history of
my province, in spite of repulse and ridicule.” The same spirit in-
volved him in other struggles to the end of his life; and, indeed, we
may almost say, beyond it. He took a prominent part in the political
controversies of his day; and few works on such subjects, which
appeared in France in modern times, produced a greater fermenta-
tion than his “ Mémoire a consulter” on the subject of the Jesuits.
In this work he maintained that the position of the Jesuits in France
was dangerous and illegal; and he must be considered as the ori-
ginator of that movement in consequence cf which their body was, a
few years later, suppressed by the government. The expression of
his opinions respecting the conduct and influence of the clergy of his
country was condemned by the ecclesiastical authorities, and was
deemed by them of a nature to exclude him from that recognition of
his being a son of the Catholic church, which is implied by the per-
formance of the funeral rite according to its ordinances. This, how-
ever, did not prevent the inhabitants of the neighbourhood and the
military stationed at Clermont from showing the regard which his
intercourse with them had inspired, by attending his sepulture in
great numbers. He was buried in a spot previously selected by
himself, in the crater of the extinct volcano in which his abode was,
in the middle of the scenes which he had from his earliest years
loved and studied, and taught others to feel a deep interest in. He
died at the age of 83, on his way to Paris in order to take his seat
in the Chamber of Peers, of which he was a member*.

* Besides his ‘‘Essay on the Extinct Volcanoes of Auvergne,” M.
de Montlosier was the author of the following works: ‘‘ Mémoire a con-
sulter sur un Systeme Religieux et Politique tendant a renverser la Re-
ligion, la Société et le Troéne”’ (1826). ‘* Dénonciation aux Cours Roy-
ales rélativement au Systéme Religieux et Politique signalé dans le Mé-
moire a consulter,’’ (1826). ‘‘ Mémoires de M. le Comte de Montlosier
sur la Révolution Frangaise, le Consulat, l’Empire, et les principaux
Evénements qui ont suivis 1755-1830.” Of this work two volumes have
appeared, which bring the narrative down to the author’s quitting the
National Assembly in 1790.

384 Geological Society.

Anselme-Gaétan Desmarest, honorary member of the Royal
Academy of Medicine, and Professor of Zoology at the Royal
Veterinary College of Alfort, was the son of Nicolas Desmarest,
who has just been mentioned as the predecessor of Montlosier in
his theory of the volcanic origin of Auvergne. The son also em-
ployed himself upon the same district ; and published an enlarged
and improved edition of his father’s map of Auvergne ;—a work
which is still spoken of with admiration, for its fidelity and skil-
ful construction, by all who explore that country. But the labours
of the younger Desmarest were principally bestowed upon the
other parts of natural history. We possess in our Library, extracted
from various journals, and presented us by the author, his “ Notes
on the impressions of marine bodies in the strata of Montmartre,”
published in 1809; his “ Memoir on the Gyrogonite,” published in
1810; to which he added, in 1812, the recognition of the analogy
of this fossil with the fruit of the Chara, pointed out by his brother-
in-law M. Léman; his review of a work by M. Daudebard de Fer-
russac, on the Fossils of Freshwater Formations, in 1813; his me-
moir on Two Genera of Fossil Chambered Shells, in 1817; and his
“Natural History of the Proper Fossil Crustaceans,” published in
1822 along with M. Brongniart’s “ Natural History of Fossil Tri-
lobites.” In the “ Dictionaire d’Histoire Naturelle,” the article Ma-
locostracés, which contains a complete account and classification of
Crustaceans, is by M. Desmarest, with others on the same subject.
In this work all the articles on Crustaceans had originally been as-
signed to Dr. Leach ; but when the lamented illness of that distin-
guished naturalist prevented his finishing this task, it was committed
to Desmarest, who carefully studied the labours of his predecessor ;
and, with most laudable industry and self-denial, made it his business
to follow his method as closely as possible. He also published a
separate work on Crustacears in 1825.

Count Kaspar Sternberg was one of those persons, so valuable in
every country, who employ the advantages of wealth and rank in
the cultivation and encouragement of science. He belonged to a
younger branch of one of the best and oldest families in Bohemia ;
and was closely connected with the persons of most elevated station
in that country. He was born the 6th of January, 1761, and re-
ceived a distinguished education at Prague; not only, as was then
common among the Bohemian nobility, through private tutors, but
by following the public course of the university. He was created
Canon of the Chapter of the metropolitan church at Ratisbon, which,
obliging him to receive the lower degree of holy orders, bound him
to celibacy. At Ratisbon, then a considerable place, and the seat
of the Diet of the German empire, he formed friendships with seve-
ral eminent persons, and especially with Count Bray (afterwards
Bavarian minister at various courts), a man of letters, and a distin-
guished botanist. Count Sternberg also cultivated botany, and be-
came an active member of the Botanical Society of Ratisbon. Du-
ring the time that Germany was a prey to the miseries of war, he
retired to his hereditary country seat Brzezina, in the circle of Pil-

Anniversary of 1839. Address of the President. 385

sen, in the north-western part of Bohemia. Here his attention was
early drawn to the coal formation, of which mineral he possessed an
extensive estate at Radnitz. He soon formed the intention of pub-
lishing representations of the fossil vegetables belonging to the coal
strata. These had already begun to excite the attention of geolo-
gists. Some of these works, containing notices on such subjects,
preceded the existence of sound geology, as the Herbarium Diluvi-
anum of Scheuchzer, the Sylva Subterranea of Beutinger, and the
Lapis Diluvii Testis of Knorr*. At the beginning of the present
century, Faujas de St. Fond had published in the Annales du Mu-
séum some impressions of leaves, not indeed belonging to the coal,
but to a later formation. These impressions were examined and
determined by Count Sternberg, in the Botanical Journal of Ratis-
bon, in 1803. In the following year appeared the first truly scien-
tific work on this subject, the “ Flora der Vorwelt” of Schlotheim,
in which the great problem which was supposed to demand a solu-
tion was, Whether the vegetables of which the traces are thus ex-
hibited belong to existing or to extinct kinds? Count Sternberg
was in Paris when he received the work of Schlotheim, and he stu-
died it carefully by the aid of the collections which exist in that
metropolis. He published in the Annales du Muséum a notice on
the analogies of these plants, but concluded with observing, that a
greater mass of facts was requisite; and that, these once collected,
the general views which belong to the subject would come out of
themselves.

Bearing in mind this remark of his own, when fortune, after the
storming of Ratisbon in 1809, set him down in the midst of the great
coal formations of Bohemia, he proceeded forthwith to manage the
working of his mines, so as to preserve as much as possible the
most remarkable impressions of fossils. Combining his own speci-
mens with those found in other places, he began to publish, in 1820,
his “Essay towards a Geognostic-botanical Representation of the
Flora of the Pre-existing World.” In this work he not only gave a
great number of very beautiful coloured engravings of vegetable
fossils, but also attempted a systematic classification of them. But
he stated, in the first portion of his work+, that the problems, im-
portant alike for botany and geology, which offered themselves,
could only be solved by combined labours on a common plan; and
after mentioning the various European Societies to which he looked
for assistance (among which he includes this Society), he adds, “ Bo-
hemia and the hereditary states of the Austrian empire, I am ready,
with some friends of science, to make the subject of continued in-
vestigation.” The specimens of which he published representations,
with many more, formed the Count’s collection at his castle of Brze-
zina; but he declared in the outset, that as soon as the National Bo-
hemian Museum at Prague was provided with the means of receiving

* To the earlier works on this subject we may add Martin’s Petrificuta
Derbiensia, published 1809; and Parkinson’s Organic Remains (1804),
which contains many plates of vegetables.

| Erster Heft, p. 16.

Phil. Mag. S. 3. Vol. 14. No. 90. May 1839. 2C

386 Geological Society.

and displaying this collection, the whole should be transferred from
Brzezina to the capital. This was afterwards done; and in this and
other ways he was one of the principal founders of the Museum at
Prague. He also gave notice, that while the collection continued in
his own residence, it was open to the inspection of every lover of
science, even in the absence of the Count himself.

The publication of Sternberg’s Flora der Vorwelt went on till
1825, after which it was discontinued till 1838, when two parts ap-
peared, terminating the work. In this last publication he states that
he is compelled to give up this undertaking, having been in a great
measure deprived of sight for two years, so that he was obliged to
devolve the greater part of such labours upon MM. Corda and Presl.
His hearing also failed him. He adds, however, that though thus
no longer able to pursue the path which he has trodden for twenty
years, he shall not fail to render to the science, of which he was one
of the founders, any service which may be in his power. This pub-
lication was the crowning labour of his life, for he did not long sur-
vive it; he retained, however, to the last the elasticity and activity
of his mind. He died very suddenly at his country seat already
mentioned, on the 20th of December, 1838, being carried off by
apoplexy in his 78th year.

In his own country his influence was highly salutary : he directed
his attention especially to the improvement of the national educa-
tion; and we cannot be surprised at finding such a person very soon
at the head of nearly all the institutions for literary and public pur-
poses. He founded the National Museum of Bohemia, of which he
was the President; gave to it his library and his various collections,
and further enriched it at various periods of his life. He was, in-
deed, zealous in all that concerned Bohemian nationality, and was
an accomplished master of the language and literature of his country :
since his death I am assured that there is hardly one Bohemian of
any class who does not mourn for him as for a most respected bene-
factor. Throughout Germany, he was looked to by all who felt an
interest in science with a respect and regard which he well merited.
The emperor Francis held him in the highest esteem; he gave him
the title of Privy Councillor, and the Grand Cross of St. Leopold,
held in that monarchy as a distinguished honour.

In the preceding sketch I have mentioned Schlotheim as one of
the predecessors of Count Sternberg in fossil botany. Although
this writer died in 1832, and was an honorary member of this So-
ciety, he has never been noticed in the annual address ; I may there-
fore here add a few words with reference to him. Baron E. F. von
Schlotheim was Privy Councillor and President of the Chamber at
the court of Gotha, and his collection of Petrifactions has long been
celebrated throughout Germany. Besides his Flora of a Former
World, or Descriptions of remarkable Seti gis of Plants, which
appeared in 1804, he published, in 1820, ‘ Petrifactenkunde, or the
Science of Petrifactions according to its present condition, illustrated
by the Description of a Collection of petrified and fossil remains of
the animal and vegetable kingdom of a former world. And in 1822

Cambridge Philosophical Society.— Royal Institution. 387

and 1823 he published Appendixes to this work. His collection was
also further made known by articles in Leonhard’s Mineralogical
Pocket Book and in the Isis. After his death a new description of
this collection was announced, but whether it appeared I am not
able to say. Schlotheim’s introduction to his account of his collec-
tion contains some extensive geological views.

It is only justice to M. de Schlotheim to add here what is said of
him by M. Adolphe Brongniart, whose own labours on fossil vege-
tables have been of such inestimable value to the geologist, and are
every year increasing in interest. ‘“‘ Almost half a century,” he says,
“ elapsed, during which no important work appeared on this subject.
It was not till 1804 that the ‘ Flora of the Ancient World,’ by M.
de Schlotheim, again turned the attention of naturalists to this branch
of science. More perfect figures, descriptions given in detail and
constructed with the precision of style which belongs to botany, and
moreover some attempts at comparison with living vegetables, showed
that this part of natural history was susceptible of being treated like
the other branches of science: and we may say, that if the author
had established a nomenclature for the vegetables which he described,
his work would have become the basis of all the succeeding labours
on the same subject.” ’

CAMBRIDGE PHILOSOPHICAL SOCIETY.

February 18th.—Dr. Graham the president, in the chair. The
conclusion of a paper by Mr. Rothman was read, ‘‘on the ancient
climate of Italy and other countries.” Also, a paper, by Mr. Potter,
*‘on the determination of the length of an undulation of light by
various methods;” and an appendix, by Mr. Green, to a former
paper on waves.

March 4th.—Dr. Graham in the chair. Various presents were
announced, and among the rest, as presents from the Natural Hi-
story Society of Liverpool, two casts, and several lithographic prints
of the footsteps of an unknown animal, found in the sandstone of
the promontory of Wirrall, which lies between the mouth of therivers
Mersey and Dee. ‘The most conspicuous of these footsteps agree
exactly with those found by Professor Kaup, in Saxony, ascribed by
him to an animal which he has termed the Chirotherium. After-
wards Mr. Hopkins gave an account, illustrated by diagrams, of the
geology of the parts of England and France in the neighbourhood of
the British Channel.

March 18th.—Dr. Graham in the chair. A communication was
made by Mr. Earnshaw, on the equilibrium of a system of particles.
After this the Astronomer Royal gave an account of the mode now
employed for observing the diurnal changes of the variation of the
magnetic needle. He also urged the importance of having observa-
tions corresponding with the simultaneous observations now made
in various parts of Europe, undertaken by some persons interested
in the subject residing in Cambridge.

FRIDAY-EVENING MEETINGS AT THE ROYAL INSTITUTION.
February 22nd.—Mr. Johnston on the leading distinctions in the
investigation of mental and physical phenomena,
2C2

388 dtoyal Academy of Sciences of Paris.

March 1st.—Mr. Brande on steel.

March 8th.—Mr. Brayley on the equilibrium of the atmosphere
as dependent on the united action of gravity and temperature.

March 15th—Mr. Cowper on pottery.

March 22nd.—Mr. Faraday on Airy’s correction of the ship’s com-
pass in an iron vessel.

ROYAL ACADEMY OF SCIENCES OF PARIS.
April 15th.—A paper ‘‘ On a new Voltaic Combination,” by W.
R. Grove, Esq., M.A., M.R.I., was communicated by M. Becquerel,
for a copy of which, as follows, we are indebted to the author.

Mr. Porrett was, I believe, the first who employed a bladder to
separate the liquids in the operating cell of the voltaic pile. M.
Becquerel, by introducing this into the exciting cells, has shown us
how to render constant the primitive intensity of the battery by
preventing cross precipitation* ; Mr. Daniell has remedied some
practical defects in M. Becquerel’s arrangement, and his form of bat-
teryis undoubtedly the best of any that have been hitherto proposedf.

In a letter published in the Phil. Mag. for February, (p. 127) I en-
deavoured to show, thatin addition tothe immense benefit derived from
constancy of action, which was the object aimed at by these gentle-
men, the combination of four elements was capable of producing a much
more powerful development of electricity than that of three, as by
this means we have nearly the sum of chemical affinities instead of
their difference; I also there suggested that if the principles I had
laid down were true, there was every probability of superior combi-
nations being discovered; I have lately been fortunate enough to
hit upon a combination which I have no hesitation in pronouncing
much more powerful than any previously known. The experiments
which led to it are curious, and possess an interest of their own, as
they prove a well-known chemical phenomenon to depend upon
electricity, and thus tighten the link which binds these two sciences.
The effect to which I allude is the dissolution of gold in nitro-muriatic
acid; this metal, as is well known, not being attacked by either of
the acids singly. The following experiments leave, I think, no doubt
as to the rationale of this phenomenon.

lst. Into the bottom of a wine glass I cemented the bowl of a
tobacco pipe ; into this was poured pure nitric acid, while muriatic
acid was poured into the wine glass to the same level : in this latter
acid two strips of gold leaf were allowed to remain for an hour, at
the end of which time they remained as bright as when first im-
mersed. A gold wire was now made to touch the nitric acid and the
extremity of one of the strips of gold leaf; this was instantly dis-
solved, while the other strip remained intact.

2nd. The experiment was inverted, but offered some difficulty, as
the gold would not remain an equally long time in the nitric acid,

* Ann. de Chimie, vol. xli. M. Becquerel, by employing another form of
diaphragm, that of moistened clay, has produced those results of electro-cry-
stallization which are so'generyally known. [See Sctent. Mem. vol. i. p. 414. |

+ Phil. Trans. 1836. [See L. and E. Phil. Mag. vol. xii p. 350.]

ew yee ee

Mr. Grove on a New Voltaic Combination. 389

from the effect of the nitrous gas; enough, however, was ascer-
tained to prove that to the gold in this acid contact made little or
no difference; while the gold in the muriatic was always dissolved.

3rd. A platina arc was used for connexion instead of gold: the
effect was the same.

4th. The outside of the pipe was coated with gold leaf, leaving
scarcely any part exposed : a strip was placed in the muriatic acid
as before, and when contact was made with the nitric acid this strip
was destroyed, while the coating of gold directly across the line of
junction was unhurt.

5th. The nitric acid was stained with a little tournesol: when
contact was made, I could not see that the muriatic acid acquired
any of the colour.

6th. Nitrate of copper was used instead of nitric acid ; the effect
was the same, but took place more slowly, and I could detect no
precipitation on the negative metal.

7th. I now made gold leaf in muriatic acid the electrodes of a
single pair of voltaic metals ; the acid was decomposed and the posi-
tive electrode was dissolved.

From all this I think we may pronounce the action to be as fol-
lows : as soon as the electric current is established, both the acids
are decomposed, the hydrogen of the muriatic unites with the oxygen
of the nitric, and the chlorine attacks the gold.

In all these cases the currents were examined with a galvanome-
ter, and in all, the gold which was dissolved represented the zinc of
an ordinary voltaic combination : the greatest deflection was obtained
with platina, gold, and the two acids. It now occurred to me, that
as gold, platina, and two acids gave so powerful an electric cur-
rent, a fortiori, the same arrangement, with the substitution of zinc
for gold, must form a combination more energetic than any yet
known. I delayed not to submit this to experiment, and was grati-
fied with the most complete success. A single pair, composed of a strip
of amalgamated zinc an inch long and a quarter of an inch wide, a
cylinder of platina three quarters of an inch high, with a tobacco-pipe
bowl and an egg cup, readily decomposed water acidulated with sul-
phuric acid. In this battery the action is constant, and there is no
precipitation on either metal : it offers the great advantage of being
able to utilize the action of concentrated nitric acid. I tried the
same arrangement, substituting for the muriatic acid caustic potass,
which was suggested to me by a well-known experiment of M. Bec-
querel : the action was equally powerful, and I should prefer this
arrangement, as there is no necessity for amalgamating the zinc, but
for a fatal objection—the nitrate of potass, crystallizing in the pores
of the earthenware, splits it to pieces; except, therefore, a new de-
scription of diaphragm be discovered which will bear the action of
powerful acids, this combination must be abandoned.

I diluted the muriatic acid with twice its volume of water and the
effect was not perceptibly inferior. I then tried sulphuric with four
or five times its volume of water; the intensity was a little diminished,
but so little that I should prefer this combination to any other, as

390 Intelligence and Miscellaneous Articles.

cheaper, exercising less local action on the zinc, and by no possibility
endangering the platina. The nitric acid may be the common acid of
commerce, but must be concentrated. If the hydrogen, instead of
being absorbed by the oxygen of the nitric acid, is evolved on the
surface of the platina, the energy of action is lowered and is no
longer constant.

Great advantage will be found in employing a cell divided by a
porous diaphragm for a decomposing cell; thus if oxygen gas be
wanted, the positive electrode should be put into dilute sulphuric
acid and the negative into concentrated nitric, If chlorine be
wanted, the positive into muriatic, the negative into nitric; if hy-
drogen, both into muriatic, the positive one being of amalgamated
zinc, &c. &c. By this means, and with a small battery of the de-
scription I am about to indicate, a traveller may carry in his pocket
an electro-chemical laboratory.

I have constructed a small battery, of a circular shape, consisting
of seven liqueur glasses and seven pipe bowls ; the diameter is four
inches, the height one inch and a quarter: this pocket battery gives
about one cubic inch of mixed gases in two minutes. The form of
this combination is in effect that of Mr. Daniell, the connexions,
however, never need adjustment but when the worn-out zinc is re-
newed ; and in a battery which M. Becquerel and myself are about
to construct, I hope to remedy another defect, viz. the necessity of
pouring solutions separately into each cell, which is troublesome and
injurious from the inequality of strength which results; I have en-
tirely remedied this in a copper and zine constant battery; but
though the process be simple, it would require more words to de-
scribe than a matter of such minor importance is worth.

LIX. Intelligence and Miscellaneous Articles.

LATANIUM—A NEW METAL.

BERZELIUS, in a letter to M. Pelouze, dated the 22nd of

¢ February, states that M. Mosander, in submitting the cerite

of Bastnaes, in which cerium was met with twenty-five years ago,
has discovered a new metal.

The oxide of cerium, separated from the mineral by the usual pro-
cess, contains nearly two-fifths of its weight of the oxide of the new
metal, merely altered by the presence of the cerium, and which, so
to speak, is hidden by it. This consideration induced M. Mosander
to give the new metal the name of Jatane or lantan.

It is prepared by calcining the nitrate of cerium, mixed with ni-
trate of latanium. The oxide of cerium loses its solubility in weak
acids; and the oxide of latanium, which is a very strong base, may
be separated by nitric acid, mixed with 100 parts of water.

Oxide of latanium is not reduced by potassium ; but by the action
of potassium on the chloride of latanium a grey metallic powder is
obtained, which oxidizes in water with the evolution of hydrogen gas,
and is converted into a white hydrate.

}
-

Fall of Meteorites at the Cape of Good Hope. 391

The sulphuret of latanium may be produced by heating the oxide
strongly in the vapour of oxide [sulphuret ?] of carbon. It is of a
pale yellow colour, decomposes water with the evolution of hydro-
sulphuric acid, and is converted into a hydrate.

The oxide of latanium is of brick-red colour, which does not ap-
pear to be owing to the presence of oxide of cerium. It is converted
by hot water into a white hydrate, which restores the blue colour of
litmus paper reddened by an acid; it is rapidly dissolved even by
very dilute acids; and when it is used in excess, it is converted into
a subsalt. The salts have an astringent taste, without any mixture
of sweetness; the crystals are usually of a rose-red colour. The
sulphate of potash does not precipitate them, unless they are mixed
with salts of cerium. When digested in a solution of hydrochlorate
of ammonia, the oxide of latanium dissolves, with the evolution of
ammonia. The atomic weight of latanium is smaller than that as-
signed to cerium; that is to say, to a mixture of the two metals.

M. Berzelius has repeated and verified the experiments of M. Mo-
sander.—L’ Institut, 14 Mars, 1889.

FALL OF METEORITES AT THE CAPE OF GOOD HOPE*.

«« On the morning of the 13th October, about nine o’clock, a fall of
stones (of which a specimen is herewith sent) occurred in the Bok-
keveld, about fifteen miles from Tulbagh, attended with the most
awful noise, louder and more appalling than the strongest artillery,
causing the air to vibrate for upwards of eighty miles in every direc-
tion. Indeed it was felt from the Cape Flats to the edge of the
Great Karroo, and again from Clan William to the river Zonder-
end, near Swellendam. The noise was awful ; and by those in the
immediate neighbourhood of the spot where the stones fell, is de-
scribed as something similar to the discharge of artillery, by those
at a greater distance as rocks rolling from a mountain; which was
the sensation at Worcester, some forty miles from the chief site of
the phenomenon. Many felt a curious sensation, especially about
the knees, asif they had been electrified. At the time of the occur-
rence I was on the very skirts of its influence, on the edge of the
Karroo, in company with the Hon. Mr. Justice Menzies. At the
moment of the explosion I witnessed a volume of the electric fluid
forcing its way from the west in the form of a Congreve rocket ; it
exploded almost immediately over my head, into apparent globules
of fire, or transparent glass. Throughout the region of the phzeno-
menon the air was highly charged with the electric fluid, especially
the night prior to the fall of the stones ; the mountains around
Worcester and the Bokkeveld being in one continued blaze of light-
ning, and some of the inhabitants described the fire as rising from
the earth. The stones (the quantity I have not been able to ascer-
tain, but supposed several cwts.) fell in the presence of a farmer,
who had with him a Hottentot, who stood so near the shower as to
become perfectly insensible for some time, either from the electricity
or from the effects of fright. ‘The stones fell in three spots, but all

* See p. 231, and also p. 368 of the present Number. ‘The specimen
mentioned by Mr. Thompson is now in the British Museum.—E, W. B.

392 Intelligence and Miscellaneous Articles.

within a square of forty or fifty yards. Some fell on hard ground,
when they were smashed into small particles ; others in soft ground,
where they were dug out. Prior to the real cause of the phenome-
non being known, it was taken for an earthquake.’ Letter from
G. Thompson, Esq. of Cape Town, dated Nov. 28, 1838, inserted in
Charlesworth’s Magazine of Natural History, vol. iii. p. 145.

“On the 13th of October last (1838) a most brilliant meteoric ap-
pearance was seen about seventy miles from Cape Town, attended
by a shower of stones which extended itself about 150 miles, that
is, some stones have been found at 10, 15, 20, 50, and so on miles,
all in the same line of direction. Some say that the stones were
so soft at first that they could be cut with a knife, and others say
that in falling the ground was torn up to some depth and a loud ex~-
plosion was heard.” Letter from E. J. Jerram, Esq. of Cape Town,
dated Jan. 29, 1839, addressed to Mr. Brayley.

SELENIURET OF MERCURY.

Del Rio and Kersten have already described some Mexican ores
of mercury which contain selenium, but hitherto they appear to have
been found only in very small quantity. Very lately M. Ehrenberg
has received some minerals from M. Carl. Ehrenberg, director of the
Real del Monte mines, among which there is a series of mercurial
ores met with at San Onufre, where they are so abundant, that it is
intended to work them on the large scale to extract the mercury.
In colour and lustre the mineral resembles fahlerz, and occurs with-
out the least indication of foliated structure, disseminated in a gan-
gue of calcareous and heavy spar, from which it is extremely difficult
to separate them in a quantitative analysis. It is entirely volatile ;
the sublimate, reduced to powder, is black, without any admixture
of red.

This mineral consists of sulphuret and seleniuret of mercury ; and
analysis shows that its composition closely approximates four atoms
of the first and one atom of the last. It is probable that these two
isomorphous bodies may combine in all proportions.—L’ Institut, 14
Mars, 1839. :

NONEXISTENCE OF CARBONATES OF QUINA AND CINCHONIA.

M. Langlois makes the following statements respecting the non-
existence of the above compounds :

Chemical works make no mention of the action of carbonic acid
upon organic bases. M. Berzelius (Chimie, tome 5,) says, however,
that carbonate of cinchonia is obtained by double decomposition
from a soluble salt of this alkali, and a solution of carbonate of pot-
ash. The decomposition certainly occurs; and a white precipitate
falls, which, after being washed, and dried between folds of paper,
effervesces slightly on the addition of weak acids, which unques-
tionably indicates the presence of a carbonate ; but this effervescence
does not occur unless the carbonate of potash has been employed in
excess. Imagining then that this effect might be occasioned by the
carbonate of potash retained in the cinchonia, notwithstanding re-
peated washings, the precipitate was treated with cold concentrated

Intelligence and Miscellaneous Articles. 393

alcohol, which did not dissolve it entirely. A white powder re-
mained, which was thrown upon a filter, and this was found to be
carbonate of potash. The alcoholic solution, exposed to the air,
evaporated slowly, and deposited crystallized cinchonia, combined
with carbonic acid.

The salts of quina, treated in the same way, yielded similar re-
sults; and hence it may be concluded, that carbonates of organic
bases do not exist.—L'Jnstitut, 28 Mars, 1839.

MICA CONTAINING POTASH AND LITHIA.

M. V. Regnault has analysed these micas; they fuse easily at a
red heat, and without suffering any sensible loss of weight, and are
afterwards easily reduced to a fine powder.

The analysis was performed by acting upon the mica, previously
fused and reduced to fine powder, with hydrochloric acid, and sepa-
rating the silica in the usual way. The alumina and peroxide of iron
were precipitated together by carbonate of ammonia; the liquors
being evaporated, after the addition of sulphuric acid, left a residue,
which, when calcined, yielded the alkaline sulphates, which were
dissolved in water, and decomposed by chloride of barium. The ex-
cess of barytes added was afterwards precipitated by dilute sulphuric
acid, added gradually; and the solution containing the alkaline
chlorides, after the addition of chloride of platina, were evaporated
nearly to dryness. By the addition of alcohol, the double chloride
of potassium and platina was separated; the lithia was determined
by difference, and by the composition of the sulphates.

In order to determine the fluorine, the mica was acted upon with
carbonate of soda, and then treated with boiling water. The alka-
line liquor was concentrated after filtration, and then subjected to a
current of carbonic acid gas, which produced an abundant precipitate
of glutinous silica. A solution of oxide of zinc in carbonate of am-
monia was afterwards added to the filtered liquor, and it was then
evaporated to dryness; the last traces of silica and alumina were
thus separated. The saline mass was treated with a small quantity
of boiling water, and the liquor was supersaturated with hydrochlo-
ric acid in a platina capsule. The solution was suffered to remain
for twenty-four hours, in order to allow the carbonic acid to sepa-
rate perfectly. It was then saturated by ammonia, and the fluorine
precipitated by chloride of calcium.

ROSE MICA LEPIDOLITE.

This mica has the form of very small rose-coloured plates. It is
found disseminated in a kaolin, which is employed in the porcelain
manufactures of Vienna. It is separated by washing from the kaolin.
The mean of four analyses gave

Silica’ hte. oh. Buse nd Reh "40)
Alltmana tet fae ee SS SEC, 26°80
Potash; ....’. ots See 9:14
Lathirald Nae eh ee eee iene NASB5
Biiorme Sie; Serie ae .. 4°40
Deutoxide of manganese 1°50—99:'09.

394 Intelligence and Miscellaneous Articles.

Yellow Mica.
Silica sere Site eS nes 49°78
WAUQMIntee. oo os CU eee OHSS
Peroxide of iron ............ 13°22
ROfAS es ec oe ee ee One
| ii) 00 lk Ds daar Ai tara ie do 4°15
Fluorine ... . SoS 4:94--100062

‘Annales de Chimie et de Physique, pp. 69-72.

METEORIC IRON FROM POTOSI.

H. M. Juben, a Lieutenant in the French Navy, among other mi-
nerals which had been presented to him, brought from Peru a piece
of meteoric iron found near Potosi in Bolivia; it was stated to him
to be meteoric iron of great purity; it is cavernous, filled with
vacuities, most of which are irregular, but some have the form of a
rhombic dodecahedron; some of them also are filled with a green-
ish vitreous substance similar to the olivine of Pallas. No traces
whatever of fusion appear, although the mineral evidently indicates
the action of a high temperature. The tenacity of this iron is ex-
tremely great, but it is readily hammered and filed. It does not
oxidize even when exposed to a moist atmosphere. Its sp. gr. is
7°736. ‘The mean of three analyses performed by M. Morren give
us its composition

J Wf OY rhe SIG ATE as BR de 90°241
Nitkel’’s;. create es 9°759
100°

This iron is remarkable on account of the large quantity of nickel ;
no trace either of copper, cobalt, or manganese was discoverable.
The specimen is deposited in the Museum of Angers.—Chronique
Scientifique, 24 Feb., 1839.

PHOSPHORESCENT POWER OF ELECTRICAL LIGHT.

M. Becquerel has read a memoir to the Institute on some new
properties which electrical light possesses of acting as a phosphores-
cent power. After a brief history of what had been previously done
with respect to phosphorescence, M. Becquerel proceeds as follows :

I shall begin with first showing that electrical light is capable of
producing phosphorescence, not as a consequence of a shock or by
electrical influence, as was formerly supposed, but on account of pro-
perties peculiar to its radiation. For this purpose some freshly cal-
cined oyster-shells are placed in aporcelain capsule, and ata distance of
about ;%, of an inch, a discharge from eighteen jars is passed through
them. ‘The shells soon became luminous, and the light disappears
more or less readily according to their degree of excitability.

On successively placing the shells at a distance of about 4, 20, 80,
130, &c. inches, the phosphorescence always appeared ; the effect di-
minishing in proportion to the distance. It is even apparent at a
much greater distance still, and where usual electrical influences are
not distinguishable. I will also add that green fluors exhibit the

Intelligence and Miscellaneous Articles. 395

same appearances when submitted to the action of electric light.
Nor is this all; if slightly excitable oyster-shells be placed at a di-
stance of several inches, the phosphorescence produced by the first
discharge is usually weak; on the second discharge it is stronger,
and on continuing the discharges, the luminous property is still fur-
ther increased, and acquires a considerable degree of intensity. It
is therefore evident, that the direct electric light, acting at a distance,
predisposes the particles of the shells more and more to become phos-
phorescent. I ought not to omit to mention, that in these cases I
perceived a smell of sulphuretted hydrogen, derived from the action
of the sulphuret of calcium on the water contained in the air, and
that it became more sensible as the number of the discharges in-
creased, which seems to indicate that the tendency to decomposition
increases with the luminosity.

These first observations being finished, and especially considering
the before-mentioned experiment, from which no inference had been
drawn, that is to say, that calcined shells inclosed in glass tubes and
exposed to electric discharges were only phosphorescent on account
of the increase of temperature, it occurred to me to try whether sub-
stances traversed by diaphragms would lose or preserve their property
of becoming phosphorescent at a distance. The substances which I
employed as screens were white glass, red glass coloured by pro-
toxide of copper, violet glass, and also of various other tints, glazed
paper and leaves of gelatin. I was perfectly aware, that except red
glass, the other coloured glasses would not admit of the passage of
simple rays, but I thought that these substances would nevertheless
suffice to afford differences sufficiently marked, as to the mode in
which electric light, the subject of my inquiry, would act.

The discharge from eighteen jars was passed through recently cal-
cined oyster-shells, contained in a capsule, at a distance of about 0°4
of an inch. The experiment was made in a dark chamber, in which
I had remained for a quarter of an hour, in order ro render the retina
sensible to feeble light, and my eyes remained closed after the dis-
charge, in order thatthe sight might not be impaired by the impression
of the electric light. The shells immediately appeared strongly illumi-
nated ; the experiment was repeated in ten minutes, a plate of glass
about 0°0117 of an inch thick being placed upon the capsule. The dis-
charge again produced phosphorescence, but in an infinitely less
degree than before the interposition of the screen. On increasing
the thickness of the glass to about 00315 inch, the phosphorescence
was still weaker, although the glass was perfectly diaphanous. This
experiment repeated at a distance of about four and even at eight
inches, still produced phosphorescence, but in a smaller degree. A
plate of glass about 0-04 of an inch thick, also gave very weak phos-
phorescence, and so also did a sheet of very transparent glazed paper
of 4 the thickness of the glass.

We have here, therefore, very diaphanous bodies, which allow of the
greater part of the luminous rays to pass, and which take away from
these same rays the property by which they render bodies phospho-
rescent. ’

396 Intelligence and Miscellaneous Articles.

A plate of red glass, of 0°08 of an inch thick, entirely deprived the
light of phosphorescent power, whereas a similar piece of violet glass
acted nearly like colourless glass, though in some cases the effect
appeared more strongly marked. Yellowish-green glass entirely de-
prived electric light which traversed it of its phosphorescent power.
It appears therefore that colourless glass deprives luminous rays of
the greater part of their phosphorescent power, and that the quan-
tity of this power which is taken away by the violet glass, is gradu-
ally increased as blue, yellow, and orange glasses are used, the last
mentioned entirely destroying the phosphorescent power.

The following experiment also confirms the effect which has been
described with screens of white glass placed in the passage of the
light: recently calcined oyster-shells were exposed to the light of a
bit of phosphorus burning in a bottle filled with oxygen gas. The
light emitted was most intense, and yet the phosphorescence which
it occasioned was slightly so.

To conclude, it is evident that electric light, besides chemical and
calorific luminous properties, also possesses phosphorescent power,
which is taken from it partly or almost totally by different sub-
stances, which allow the light to pass through them without any sen-
sible diminution.—L’Jnstitut, No. 270.

ON THE PREPARATION OF SELENIC ACID. BY HENRY ROSE.

M. Mitscherlich’s process for preparing this acid with selenium or
a metallic seleniuret consists, as is well known, in fusing them with
nitrate of potash or soda. According to Berzelius, it may be obtained
with selenious acid by converting it into selenite of potash, mixing
the solution of this salt with a little caustic potash, and passing chlo-
rine gas through the solution to complete saturation : by this process
there is obtained a mixture of chloride of potassium and seleniate of
potash. These two methods yield selenic acid combined with an
alkali, and it is difficult and tedious to separate and combine it with
certain other bases.

In his first experiments with chlorine gas upon the metallic sele-
niurets of the Hartz, the solution obtained by mixing the voltatile
chloride of selenium with water, through which excess of chlorine was
passed, yielded no precipitate of selenium on the addition of a solu-
tion of an alkaline sulphite; and this re-agent produced no precipi-
tate of selenium till hydrochloric acid was added and boiled with it
for a long time. The selenium evidently existed in the liquor in the
state of selenic acid, which was not reduced to that of selenium by
the alkaline sulphites, till the moment at which the hydrochloric
acid converted it into selenious acid.

If then it be desired to prepare free selenic acid, the best process
is that of passing chlorine gas through a solution of chloride of sele-
nium or selenious acid. It is then obtained, mixed only with hy-
drochloric acid, which when dilute and cold, does not reduce the se-
lenic acid.

The best method of producing selenic acid immediately from sele-
nium is the following : reduce the selenium to coarse powder, put it

Ee ee! ———

Intelligence and Miscellaneous Articles. 397

into a moderate sized glass vessel, and cover it to the depth of a few
lines with water. Into this mixture chlorine gas is to be slow pass-
ed, through a pierced cork in the bottle; the gas tube is to be di-
rected upon the selenium through the stratum of water. The sele-
nium is at first converted into brown liquid chloride of selenium, and
then into white solid chloride, before it dissolves in the water.

When the liquid chloride of selenium has been formed, it may re-
main for a considerable time under the water, if that be suffered to
remain undisturbed; but when by agitation they are mixed, the water
becomes red, on account of the finely divided selenium ; for as is well
known, the chloride on mixing with water deposits a portion of its
selenium; but the chloride is readily soluble in water by means of
chlorine gas.

When the selenium is perfectly dissolved in the smali quantity of
water, the solution is largely diluted with water, and chlorine gas is
again passed into it until it is in excess. The excess of chlorine is
afterwards allowed to evaporate in a capsule exposed to the air, or
by the application of a very gentle heat; by this there is obtained a
solution of selenic acid, which contains hydrochloric acid, but no se-
lenious acid.

1°643 gram of selenium converted by this process into selenic
acid, yielded by the addition of a solution of chloride of barium 5°787
gram of seleniate of barytes. By calculation, this quantity ought to
yield 5°819 of the barytic salt. ‘The small difference of 0:032 gram,
is partly owing to the vaporization of a small portion of the chloride
of selenium by the excess of chlorine, and also partly because the
seleniate of barytes is not as completely insoluble in an acid solution
as the sulphate of barytes.—Jbid.

ANALYSIS OF CRYSTALLIZED PERIKLINE. BY M.C, 1. THAULON
IN H. ROSE’S LABORATORY.

Sybian es Hae .... 69,00
Alumind# 6. /iaen se 19,43
Soda .. 11,47
Tame} estes kere ss 0,20

G. Rose found the specific gravity of crystals of perikline from the
Tyrol, reduced to a coarse powder, to be from 2,637 to 2,645, and
he concludes from the analysis and specific gravity that perikline and
albite, or cleavelandite are one and the same mineral *.

Poggendorff’s Annalen, vol. 42. p. 571.

CISSAMPELIN, A NEW VEGETABLE COMPOUND.

M. Wiggers states that he has discovered a new vegetable base
in the root of the Cissampelos Pareira; it is obtained by repeated
boiling the root in water containing sulphuric acid, and mixing the
decoctions with carbonate of soda; a brownish grey precipitate is

* The forms and measurements are also similar, except that the crystals
of cleayelandite are usually twins and those of perikline single ones.—
Evit,

398 Intelligence and Miscellaneous Articles.

thus obtained, which is washed, and then redissolved in water con-~
taining sulphuric acid. This solution is to be treated with animal
charcoal ; carbonate of soda added, precipitated a dirty yellow sub-
stance, which is to be dried, pulverized, and frequently digested in
wether. By this operation a nearly colourless solution is procured,
which by the distillation of the «ther leaves the cissampelin; in
order to purify this substance completely it is to be dissolved in di-
lute acetic acid, and the solution when diluted and moderately heat-
ed is to be again precipitated by carbonate of soda, and the precipi-
tate carefully washed and dried.

M. Feneulle had previously examined this root, and had noticed
the existence of a yellow bitter substance in it, which was probably
impure cissampelin.—Journal de Pharmacie, Jan. 1839.

ANALYSIS OF CRYSTALLIZED OLIGOCLAS * FROM ARENDAL OR
SODA-SPODUMENE. BY ROBERT HAGEN IN THE LABORA-
TORY OF H. ROSE.

SOUAT ee Grete eek cme 9,37
Potash iat Pe 2,19
{LTS ge Sa NL Sea 2,44
ALS Se a ee ee 0,77
Alanna ee ee ee FD egg
ouice me ee ier. taletes. tele 63,81

101,37
Poggendorf’s Annalen, vol. 44. p. 329.

ACTION OF ACIDS ON IODIDE OF SODIUM. BY JUSTUS LIEBIG.

M.Preuss has described in the 26th vol. of the Annales de Pharmacie,
a peculiar property of iodide of sodium obtained by dissolving iodine
in a solution of soda, evaporation and calcination. The fused mass,
after solution in water, yielded crystals, which were more difficultly
soluble than iodide of sodium, and the solution immediately gave a
precipitate of iodine on the addition of hydrochloric and sulphuric
acid; this property is possessed by iodide of sodium only when
treated with certain oxacids, as nitric acid, &c., and then in a much
smaller degree.

This property is explained by the circumstance, that if iodate of
soda be calcined, either with or without excess of alkali, this salt
allows iodine to separate in the latter case, and is decomposed into
oxygen, and a compound first noticed by M. Magnus. It may be
considered as a basic hypoiodite of soda IO + 2.NaQO; is not de-
composed a heat below whiteness, and is by water converted into
iodide of sodium and iodate of soda.

The crystals which M. Preuss obtained from the fused mass, are
formed of a double compound of iodate of soda and iodide of sodium.
By the addition of an acid to the solution, the scdium of the iodide

* We have seen several specimens in this country ticketed oligoclas, not
one of which bore any resemblance to soda-spodumene, but were apparently
green cleavelandite—Ep11.

Meteorological Society.— Meteorological Observations. 399

of sodium is oxidized at the expense of the oxygen of the iodic acid,
of the iodate of soda ; and the iodine of the latter, as well as of the
iodide of sodium, separate in the state of a thick precipitate: this
observation ought to be attended to in preparing the iodide of sodium.
The best plan is to redissolve the mass obtained by dissolving the
iodine in liquid soda, and heated to redness, and pass hydrosulphuric
acid gas into it, until no more sulphur is precipitated, to separate
this by the filter and to crystallize the iodide of sodium.—Ibid.

METEOROLOGICAL SOCIETY.

Avolume has made its appearance under the title of Transactions
of the Meteorological Society. As it includes matter which was
not deemed fit for publication by the Council of the Society, some
members of that body think that the subject requires explanation,
and desire not to be held responsible for its contents.

METEOROLOGICAL OBSERVATIONS FOR MARCH, 1839.

Chiswick.—March 1. Cloudy. 2% Very fine. 3. Foggy: fine. 4. Cold
haze. 5. Bleak and cold. 6. Frosty. 7. Sharp frost. 8. Cloudy and cold.
9. Frosty: fine. 10. Frosty: cloudy. 11. Dry haze, 12. Frosty: hazy.
13. Hazy. 14,15. Rain. 16. Fine. 17. Overcast. 18. Cold haze. 19.
Cloudy: frosty at night. 20. Rain. 21. Cloudy: fine: rain. 22. Cloudy.
23,24. Fine. 25. Overcast. 26. Dry haze. 27,28. Showery. 29. Fine.
$0. Cold dry haze. 31. Overcast: rain.

Boston.— March 1—3. Cloudy. 4. Fine. 5. Cloudy. 6. Cloudy: hail and
snow early a.m.: more snow r.M. 7. Cloudy: snow early a.m. 8. Stormy with
snow. 9—12, Fine. 18—15. Rain: rain early a.m. 16. Cloudy: rain early
Am. 17. Cloudy. 18. Cloudy: snow a.m. 19, 20. Cloudy. 21. Cloudy:
rain a.m. 22—24, Cloudy. 25,26. Fine. 27. Cloudy: rain early a.m. : rain
a.m. 28. Cloudy: rain, hail, and snow with thunder and lightning p.m. 29—
31. Fine.

Applegarth Manse, Dumfries-shire.—March 1. Occasional showers a.m. : heavy
rain and windr.m. 2. Fine spring day: little raw frost morning. 3. Clear
day: wind rather piercing. 4. Cold and ungenial. 5. Cold: dry a.m.: slight
snow p.m. 6. Calm cold day: frost keen. 7. Thesame: showers of snow P.M. :
frost. 8. Cold and bleak : hills white: frost continued. 9. Frost continuing :
mod. barometer falling. 10. Still frosty: fine day though cold. _11. Snow
two inches deep: frost giving way. 12. Snow gone: very chill and slight frost.
18. Temperate: wet afternoon. 14. Damp day: rain in the evening. 15.
Calm moist day: drizzling r.m. 16. Spring day, though somewhat raw: rain
pM. 17. Cold and stormy: hills white: frost r.m. 18. Quietday: frost gone :
drizzling pt. 19. Frosty morning: moderate: cloudyr.m. 20. Moist all
day: rain heavy y.m. 21. Mild spring day: occasional slight showers: wind.
22. Boisterous morning, with severe snow showers. 2S. Unsettled weather:
slight showers, with wind. 24. Still very changeable: occasional showers. 25.
Showery: unsettled: snow on the hills. 26. Hoar-frost morning : ice a quarter
of an inch thick: rainr.m. 27. Heavy rain a.m.: cleared up: rain again v.m.
28, Rainy morning: cleared up and was fine. 29. Cold drying day: threaten-
ing frost ym. $0, Very cold anddry: cloudyr.M. 31. Cold: threatening
rain came on P.M.

Sun, 25 days. Wind westerly, 2 days.

Rain, 15 days. Calm, 9 days.

Frost, 10 days. Moderate, 9 days.

Snow, 6 days. Brisk, 8 days.

Wind southerly, 13 days. Strong breeze, 3 days.
easterly, 9 days. Stormy, 2 days.

— northerly, 7 days,

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THE
LONDON ann EDINBURGH
PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

[THIRD SERIES.]

JUNE 1839.

LX. Experiments upon the Products of Respiration at dif-
ferent Periods of the Day. By Cuaries T. Coatruurr,

Esq.*

f rue apparatus employed in the following experiments for

ascertaining the amount of carbonic acid gas respired,
differs in its construction from any that has hitherto been
used for a similar purpose; but (although original in its con-
struction,) it may claim advantages, both as regards simplicity
and utility, which will most probably be admitted by those
who are conversant with gaseous manipulations.

It consists of a cylindrical glass tube 24} inches long, and
0°55 inch in diameter, terminated at each extremity by a brass
cap, into which a stop-cock may be screwed. ‘The glass tube
is accurately divided into 175 equal parts, by equal measures
of mercury, and the divisions are numbered on opposite sides
of the tube in such a manner, that let either end be upper-
most, the graduations may be instantly read. Every experi-
ment may thus be tested by a double reading, by simply in-
verting the tube, and waiting a few seconds until the liquid
employed for any examination has drained to its ultimate
level.

The total capacity of the tube is about 5°33 cubic inches,
and each division is separated by a space exceeding }th of an
inch.

The reagent used was a clear saturated solution of quick-
lime in distilled water, with which a preliminary experiment
was made for the purpose of ascertaining the extent of atmo-

* Communicated by the Author.

Phil, Mag. 8.3. Vol. 14. No. 91. June 1839. 2D

402 Mr. Coathupe’s Experiments on the Products

spheric tension, to supply the necessary corrections in an
easy and sufficiently practical manner.

The experiment and results were as follows :

The stop-cocks being firmly screwed into the brass caps,
each in its own place as marked previously to the graduation
of the tube, and both plugs turned for the free admission of
air, the one extremity was immersed in lime-water and the lips
were applied to the other; then gently sucking the air from
the tube until the lime-water had reached within 4 or 5 inches
of the upper extremity, the upper stop-cock was closed, and
subsequently the lower one.

The lower surface of the lime-water appeared between the
divisions 36 and 37. Now opening the upper cock to re-
lieve the tension, closing it again and opening the lower
cock, a small quantity of the Jime-water escaped, after which
the lower cock was closed, and the lower surface of the lime-
water appeared between the divisions 38 and 39.

By repeating these alternate restorations of the tension ex-
ercised upon the air included within the tube, the following
results were obtained, taking in all cases the nearest approxi-
mation to either 4ths or 3rds of a whole division.

TaBLe or TENSION.
Barometer 30-2 inches. Thermometer 48° Fahrenheit,
Ist, air under tension. Air under subsequent tension.

*37°5 parts became after relieving 39:5 parts difference
TENSION cocccccegsovececccves 2.

39°5 do. do. do. 41°5 do,

41°5 do. do. do. 43°75 do,

43°75 do. do, do. 46° do. 2-95
46° do. do. do, 48°25 do.

48°25 do. do. do. 50°5 do.

50°5 do. do. do, 53" do.)

53° do. do, do. 58°h ido. .: |

55°5 do, do. ‘do. 58° do, 2°5
58° ~~ do. do, do, 60°5 do,

60°5 do. do. do. Gee day:

From 63 to 125 the differences were three divisions or parts,
upon each remission, and subsequent restoration of tension ;

— from 125 to 1301, the differences were 2°75 parts each ;

— from 130'5 to 188, they were 2°5 parts, ... .. do.

— from 138 to 145, they were 2°33 parts... ... do.

— from 145 to 151, they were 2 parts... «+ do,

* From the graduation stated as 37:5 parts, to the terminating orifice
of the lower stop-cock, the column of lime-water measured 21°20 inches.
From plug of upper stop-cock to 37-5° = 6:25 inches.

of Respiration at different Periods of the Day. 403

The air respired was in most cases retained in a caoutchoue
( Mackintosh”) bag furnished with a brass stop-cock and
connecter, and capable of containing 1000 cubic inches. It
was invariably filled by successive respirations, and great care
was taken to obviate the possibility of inspiring any air that
had been once respired.

The mode of conducting the experiments was as follows :—

The caoutchoue bag having been filled with respired air,
the long graduated tube (with its stop-cocks annexed) having
been swilled out with distilled water, and drained, and a small
evaporating vessel filled with lime-water, the tube with its
stop-cocks was screwed to the connecter of the stop-cock of
the caoutchouc bag. The bag was laid upon a chair, while
with the knee considerable pressure was exerted upon it, and
having opened all the communications between the interior of
the bag and the atmospheric air, the pressure upon the bag
was continued until about 200 cubic inches of its contents
had passed through the tube. The cock at the further ex-
tremity of the tube was now closed, and the pressure upon
the bag being continued with increased force, the cock at the
nearer extremity of the tube was closed. Having secured the
stop-cock of the caoutchouc bag, the tube with its own stop-
cocks was disconnected. (It is evident that the air included
within the tube must be under pressure; and the object for
producing this effect is, that the small quantity of atmospheric
air that is retained below the plug of the cock shall be dis-
placed when the extremity of the cock is immersed in the
lime-water. The accomplishment of this object is fully known
by the gurgling noise that accompanies the opening of the
cock after its immersion.)

The stop-cock terminating one of the extremities of the
tube was now inserted into the vessel that contained the lime-
water: the plug was turned for the free egress of the atmo-
spheric air retained below it, and for the subsequent ingress
of the reagent; the lips were applied to the orifice of the
upper stop-cock, and the process of exhaustion having been
commenced, the upper plug was gently turned, and the ex-
haustion steadily continued until the reagent had risen so as
to occupy about 30 or 40, or more, of the lower divisions of
the tube. The upper stop-cock was then secured, and after
a moment’s pause the lower one was secured. The number
of divisions unoccupied by the lime-water were now noted,
the tube being held upright, and the lower surface of the
water observed.

The finger was applied to the lower orifice of the cock
which had been immersed, in order to retain that portion of

2D2

4.04 Mr. Coathupe’s Experiments on the Products

the lime-water which occupied the space below the plug. The
tube with its contents were well agitated, the finger was re-
moved from the orifice of the stop-cock, the same extremity
was again immersed in the lime-water, and the plug of the
cock gently turned.

As soon as the lime-water had risen within the tube to its
fixed level, the cock was closed again; the finger replaced
upon the lower orifice, and agitation renewed.

This process was repeated until the lime-water ceased to
absorb any of the air contained within the tube. ‘Two opera-
tions, however, were generally sufficient. ‘The tube was then
hanged up by a loop of wire against a corner of the wall, and
when the interior had drained to a permanent level, the upper
cock was opened; a smali quantity of air immediately rushed
into the tube to relieve the tension, and with it generally a
single drop of lime-water that had occupied the small space
within the bore of the upper cock beneath its plug.

The difference between the number of divisions, or parts,
first observed to be unoccupied by the lime-water, and the
number of parts lastly observed to be unoccupied, is the num-
ber of parts of carbonic acid gas that was contained in the
number of parts first observed.

As these experiments were commenced and concluded with
as little delay as possible, it was not thought necessary to re-
gister the height of the barometer, nor the temperature ; but
every precaution was taken to commence and conclude every
set of experiments from the same bag of air, under precisely
similar circumstances. ‘The tube, the bag of air, and the
lime-water were invariably of the same temperature, both
before and after each experiment.

The periods selected for the experiments were,

From 8 a.m. to 93 a.m. before breakfast.
9} a.m. to 12 noon ) during the digestion of break-
12 noon to 1 p.m. fast and before “ luncheon.”
1 p.m. to 5} p.m. before dinner.
5ipm.to 8$p.m, during the digestion of dinner.
$2 p.m. to 12 night.
Habits of the operator.
At 9} a.m. a slender breakfast.

1 p.m. to 2 p.m. do. ** luncheon.”
5i p.m, a good dinner, with a pint of wine.
83 p.m. one small cup of tea.

10 p.m. occasionally one glass of weak brandy and

water.
12 to 1. bed time.
Age, 38 years. Stature, 5 feet 8 inches. Weight about

140 pounds,

of Respiration at different Periods of the Day. 405

Average pulse, 60 to 62 per minute. Average inspira-
tion, 18 to 21 per minute.—Vide p. 409, Epitome.

First Interval, from 8 a.m. to 91 a.m. (before breakfast.)

Feb. 4th. at S$a.m. 137 parts of fe 130°

spired air, became ee eee

» at9am. 1245 do. 118°25 .«. do. 5°02 = do.

» »» PFam.111'25 do. 105°25 .. do. 5°39 ~— do.

5th. ,, 8 a.m. 108: do. O9°5: dor (50 0. dO:

» » Sgam.128°75 do. 120°... do. 6°79 ~— do.

» 9 OFa.m. 119° do. 1145. do. 3°80. do.

6th. ,, 8 a.m. 76°5 do. (2a) don 5:22 * do:

et eran. 131°25"' | do: 124°75 .. do. 4°95 ~— do.

» » 9am. 1095 do. TO5*% s.edos'4-11>% do:

iitsyer “earl 22°O5 +) «dos DESO) saidoi/3-47 do:

solttanee. taste” LOS" do. 100° «. do. 4°76 = do.

7th. ,, 8 a.m. 112°5 do. 108°5 «. do. 4°00 ~— do.

» > GFa.m. 105° do. 100°5 .. do. 4°28 ~— do.

Sth.,, 8am. 81° do. 78:25 «. do. 3°40 do.
s o 92°5 do. SOE GOs oro © doe

3 3 92°5 do. SOF | 5 Os S716, 80.

5 > 87° do. 84°. do. 3°45 = do.

} » 9 am. 113° do. 108°25 .. do. 4°20 do.
; shale 112-25 do. 108° .«. do. 3°78 = do.
, 9th. at 8 a.m. 124° do. EUL2O2e ee idono22) do:
5 FP 121° do. Wiis? b71doS30) Ado:
x 5 132°5 do. 1285 .. do. 3°02 do.
’ » 9 9eam.115°3 do. 112°6) 2% doi231, » “do.
12th.,, 8am.116°75 do. 112°50 .. do. 3°64 do.
; 35 * 120°5 do. 115°80 .. do. 3:90 do.
= ., 121°5 do. 116°80 .. do. 3°86 — do.

» » Seam. 133° do. 127°50 .«. do. 4°13 ~— do.

is if 108° do. 103°50 .. do. 4°17 = do.

E 5 104° do. 99°80 .. do. 4°04 do.

13th. ,,8a.m. 99° do. 94-00 .. do. 5°00 do.

33 Fs 104: do. 99°50 .. do. 4°32 ~— do.

~ a 122 do. 116°50 ». do. 4°90 = do.

Total of 32 exp. 3590°3 , - : 5 3437°25
3437°25

153°05 parts were absorbed by lime-water.
and 3590°3 : 153°05 : : 100 : 4°262 per cent.

The average therefore of 32 experiments made before
breakfast, and comprising 8 days, appears to indicate 4°262
per cent. of carbonic acid gas in the air respired.

If we correct the above for tension, as per table at page
402, it will become about 4°37 per cent.

N.B. The average correction for tensiou, computed from

406 Mr. Coathupe’s Experiments on the Products

an average of 124 experiments, gives 0°11 per cent. additive
to the apparent per centage of carbonic acid gas as derived
from any direct experiment.

Second Interval. 93 a.m. to 12 noon.

Feb. 5th. at 1l a.m. 134 parts of re-

spired air, et 131° .. loss 2°24 per cent.

4th. 5, llam. 110° do. 105°... do. 4°54 = do.
5; 43@a2.n00n L185 ~ do. 113:25 .«. do. 4°33 do.
6th. ,, 10 am. 110°25 do. 105°75 .. do. 4°08 ~— do.
» oe Aleem. 13165 do. 124°75 «. do. 5°13 = do.
7th.,, llfam. 1005 do. 97°5 .«. do.2'98 do.
8th.,, llfam. 1285 do. 124 +. do. 3°5 do.
* A 109° do. 1045 .«. do. 4°12 = do.
. 4 118 do. 1U8:007.do. 4:23 n 00:
a + 115° do. 110°25 .. do. 4°13 ~— do.
Oth. ,, 115.a.m. 106° do. 102-5 .. do. 3:30 = do.
” ” 93°3 do. 90°3. .«. do. 3°22 = do.
12th. ,, LlZa.m.116°75 do. 1123 °°. do. 3°81 .. do.
a s 110.5 = do. 106°3. .. do. 3°80 ~— do.
3 5; 96°0 do. 93:0 .. do. 3°12 do.
Total of 15 exp. 1697°8 : 3 : - 1633°4
1633°4

“. 64°4 parts were absorbed by the lime-water.
and 1697°8 : 64°4 : : 100 : 3°79 per cent.

The average therefore of 15 experiments upon the air re-
spired between 10 a.m, and noon, and comprising 7 days,
indicates 3°79 per cent. of carbonic acid gas, which corrected
for tension will be 3°90 per cent.

Third Interval. 12 noon to 1 p.m.

Feb. 5th. at 124 p.m. 100° parts of re- ta 4
+P spired air, became \ 96°5 .. loss 4°5 per cent.
6th. ,, 12% p.m. 128° do. 122) .«. do.468 do.
Vike. Le pabe cee” do. 117°5 .. do. 3°90 do.
Sth. ,, 125 pm. 121°5 = do. 116°75 .. do. 3°90 do.
12th.,, 1 p.m. 106° do. 101°66 .. do. 4°10 do.

ee 1155 do. 1115 .. do. 3:46 do.
5 i 110°5 do. 106°. do. 4°07— do.
Total of 7 exp. 802°5 : : ‘ . 77191
771°91

“. 30°59 parts were absorbed by the lime-water.

and 802°5 : 30°59 : : 100 : 3°81 per cent.
The average therefore of 7 experiments upon the air re-
spired between 12 noon and 1 p.m., and comprising 5 days,

of Respiration at different Periods of the Day. 407

indicates 3°81 per cent. of carbonic acid gas, which corrected
for tension will be 3-92 per cent.

Fourth Interval, from 1 p.m. to 52 p.m. (before dinner.)

Jan. 31. at 2 p.m. 144°5 parts of air 4 ; ;
P respired, became \ 135 -. loss 6°57 per cent.
x is 148° do. 138° ~. do..6°75 do.
i pero. 15D: do. 12895 =. do. 4°81 ~— do.
Feb. 4th. ,, 3¢ p.m. 99°5 do. 97° . do. 2:5 do.
» 9 dsp-m. 100°5 do. 94°5 =... do. 60 do.
othe .0 pm. 98: do. QSrh - eGo do.
Gth. >, Spm. 97°5 do. 92°57 do'5312 "do.
7th. 2 p.m.1145 do. 1095 .. do. 4°36 do.
» » 2pm. 99 do. 96°75
” » 99° do. ot foe ‘i
- : 100° ne. 9775 f° do. 2°25 do.
- 100: do. 98:
3 9 Da pm. 99°5 do. 95° «. do. 4°5 do.
>» 3S pm. 116 do. —-112°75

; ” ” 98: do. 93°5
’ ” 115° do. 111°25 4 i
é ” 96°5 do. 93° « do. 3°56 do.
» ” Tess dos 109°
” ” 86° do. 82°75 J

99 fa75p ees, |, LOE" do. 101°5 “. do. 3°33 do.
» » Of pm. 131° do. 128°5 .. do. 1:90 do.
8th. 4pm. 111: do. 10575 .. do. 4°73 do.
ba, nan Duden 1 O48 do. 91°5 «. do. 2°66 = do.
llth. 55pm. 106°75 = do. 102: “. do. 4°45 do.

” ” 99°5 do. 95°38 a0, Sc2 Nu (AG:
oo Piss 1194 do. 1135 .. do.4°94 do.
12th. 5pm. 117°66. .\do. TIZ:b, © vs 0. 4°38") | doe
Ailend 1043 do. 995 .. do.460 do.
f : 120°5 do. 115° .. do. 4°56 = do.

Total of Q9exp. 316836 . . . « 308955
3039:55

“. _128°81 parts were absorbed by the lime-water.
and 3168°36 : 12881 :: 100: 4°06 per cent.

The average therefore of 29 experiments upon the air re-
spired between 2 p.m. and 53 p.m., and comprising 8 days,
indicates 4°06 per cent. of carbonic acid gas, which corrected
for tension will be 4°17 per cent.

Fifih Interval, from 5} p.m. to 83 p.m. (during digestion.)
Jan. 31st. at 84 p.m. 124° parts of ef 121°

: .. loss 2°42 per cent.
spired air, became pal

Carried forward “194 242

408 .Mr. Coathupe’s Experiments on the Products

Brought forward 124° 242
Feb. 3rd. at 73p.m. 1395 air respired 126°5 __.*. loss 4°54 percent.

4th. ,, 72 p.m. 110° do. 106° -. do. 3°64 do.
» » Si pm. 10425 do. 100°5—s «ws. dow 3°59 do.
5th. 5 7pm. 114°5 do. 110° -. do. 3°93 do.
>. 9 8pm. 103: do. 99: “. do. 3°88 — do.
6th.,, 7E pm. 83°5 do. 82: -. do. 1°80 do.
» tsaseipia. L195 do. 11G-25- ..,.do.2°72. alos
7th. ,, 85 p.m. 101° do. 96° “. do. 4°95 do.
99 m3 97:25 -.do. 94° “. do. 3°34 do.
11th. ,, 85 pm. 125°2 do. 120°5 —«. do. 3°75 ~— do.

£ % 116° do. 112. -. do. 3°45 do.
Ks = 121° do. 1163. _—«.. do. 3°88 ~— do.
12th. ,, 8i p.m. 120° do. LUG? os js 0.63 SoumO:
oe AS 107°5 do. 104° “. do. 2°80 do.
2) by 110°5 do. 107: -. do. 3°16 = do.

» » S¢ pm. 1185 do. 114° -. do. 3°81 = do.

Total of 17 exp. 19082. : . . 1841°05
1841°05

we GTS parts were absorbed by the lime-water.

and 19082 : 67°15 :: 100: 3°52 per cent.

The average therefore of 17 experiments upon the air re-
spired between 7 p.m. and 8} p.m., and comprising 8 days, in-
dicates 3°52 per cent. of carbonic acid gas, which, corrected
for tension, will be 3°63 per cent.

Sixth Interval, from 8? p.m. to 12 night.

Feb. 3rd. at 12 night 135° parts of aot 1965». loss 6-3 percent.
spired air, became
4th. ,, 113 p.m. 117°5 do. | 11E5,. 20 dora: 19s Mo:
» 9 12 night 124° do. 1185 .*. do. 443 do.
a2 a 97° do. 92:5 _—«w. do. 4°64 =o.
5th. ,, 114 p.m.127°5 do. 121°5...do0.4°7 do.
» 12 night 113° do. 109° “. do. 3°54 = do.

”

6th. ;, 92 p.m. 126° do.) 120°5 " wedo. 3°57 “ade.
» 39 11} p.m. 122: do... WIS hat, 2: do. 27870 ade.

jth. 9 pm. 96°75 .. do. 94°95 .«. do. 260 do.
55 > 11¢ pm. 133° 0... Ler -. do. 4°51 ~— do.
9 55 115 pm. 111- do. 1065 .. do. 4°05 do.
8th. ,, 103 p.m. 105° do. 102° . do. 2°85 do.
. sé 1C0: do. 96> .«. do. 4°00 do.
s 110°5 do. 107°5y ss, do. 2:7,
93 + 97°5 do. 94 ~=«. do. 3°59_~—s do
» »112night 111°5 do. 106°75 .. do. 4°26 = do.
“5 > 95°5 do. 91:25 .. do. 4°43 — do.
” » 96° do. OF tec. GOs 4017 endo.

Carried forward 2018°77 ‘ 1936°75

Se a ee ee

ae

of Respiration at different Periods of the Day. 409

Brought forward 2018°77 . 1936°57
Feb.11th. at 114 p.m.124°3 airrespired 119°5 .*. do. 3°86 do.

5 53 11266 do. 107°3. .*. do. 4°75. do.
$s 59 107°66 = do. 102s xt (O05 592 oO, AO:
12th. ,, 11 p.m. 133° do. 129 nO. 3 OO). .do;
x s 116°5 do. 13 + do: 3:00), .do:
- 3 J15°5 do. WEL5 do. 3:47. do:
Total of 24 exp. 2728°37 - 2619°05
2619°05

109°32 parts were absorbed by the lime-water.
2'728°37 : 109°32: : 100 : 4°01 per cent.

The average therefore of 24 experiments upon the air re-
spired between 9 p.m. and midnight, and comprising eight
days, indicates 4°01 per cent. of carbonic acid gas, which
corrected for tension will be 4°12 per cent.

The average of all the experiments together, 124 in num-
ber, and comprising almost every hour of the day between
8 a.m. and midnight, and including a period of 8 days,
gives

13895°53 : 553°32 :: 100: 3°9819 per cent., which when
corrected for tension, indicates 4°09 per cent. as the total
daily average of the carbonic acid gas in the air respired
from the lungs.

Epitome of the Results.

Ist period 8 a.m. to 93 a.m. 32 exp. indicated 4°37) — 4
2nd do. 10am. to12noon 15 do. do. 3:90| 9 &
3rd do. 12noonto lpm. 7 do. do. 3:92\ 8°3
4th do. 2pm. to 5hpm. 29 do do 4#17f 8%
5th do: 7p.m. to 8ipm. 17 do. do. 363| 32
6th do. 9p.m. tomidnight 24 do. do. 412) *§

124 exp. comprising 8 days.
Hence we find the carbonic acid gas produced by respiration
to be a variable quantity, that it is less during the period of
active digestion, that it increases with increased abstinencefrom
food; and that it varies in the same individual at similar
periods of different days. It also appeared during these ex-
periments, that excitement of any kind (whether from the ex-
hilarating stimulus of wine, or from the irritating annoyances
which are wont to occur to most folks who are actively en-
gaged,) caused a diminution of carbonic acid in the air re-
spired, as compared with the ordinary average of that re-
spired at a similar period of the day, and during a state of
ordinary tranquillity. Zhe total daily average indicated 4°09

i

410 Mr. Coathupe’s Experiments on the Products

per cent. of carbonic acid gas. The maximum observed at
any single examination was 7°98 per cent. It was at 8 a.m.
February 5th. The minimum observed at any single exami-
nation was 1°91 per cent. It was at 74 p.m. February 7th.

C.T.C., February 14th, 1839.

Having referred to some very interesting experiments made
by Messrs. Allen and Pepys at the laboratory of the Royal
Institution, and recorded in the ‘ Philosophical Transactions
of the Royal Society,” published in the year 1809, I was much
astonished to find results differing widely from my own; and
therefore, with a view to ascertain the cause of these differ-
ences, I tested my own results by a few collateral experi-
ments, which were as follows:

Feb. 18. Air respired into a bag at 8 a.m.

No. 1. 121°25 parts became 117. .. loss = mt org

No.2. 89°25 do. do. 86... do. 364f 54
2715
.". average loss = 3°57 p. cent.

which, corrected for tension, will be 3°68 per cent.

$2 parts of the residual air from No. 1. experiment, after the
abstraction of the carbonic acid gas by lime-water, were
mixed with 13 parts of dry hydrogen gas received over mer-
cury. The eudiometer contained 45 parts, the interior and
exterior surfaces of the mercury being adjusted to the same
level.

The thermometer stood at 47° Fahrenheit. ‘The barome-
ter at 29°5 in. a Dobereiner’s ball of spongy platina was in-
troduced into the mixture, and it absorbed 16°75 parts.

Therefore the 32 parts of residual air contained 5°58 parts
of oxygen; and 100 parts of the respired air, minus the 3°68
parts of carbonic acid gas abstracted by the lime-water
= 96°32 parts, must contain

Oxygen.
32: 5°58: : 96°32 : 1679 parts oxygen.
and 16°79 parts of oxygen + 3°68 parts of carbonic acid gas
= 20°47 parts represent the total quantity of oxygen that
appeared to have existed in the atmospheric air previous to
its having been respired.

Now as it is very well known that ordinary atmospheric air
contains 21 per cent. of oxygen and 79 percent. of nitrogen, and
that the formation of any quantity of carbonic acid gas must
necessarily require precisely its own volume of oxygen ; also,
that air when emanating from the moist surface of the cells
of the lungs must contain 1°21 per cent. of aqueous vapour at

of Respiration at different Periods of the Day. 411

47° Fahrenheit when the barometer stands at 30 inches; we
demonstrate the constituents of 100 parts of air which had
passed through the lungs for this test experiment to be
16°79 parts oxygen.
3°68 do. carbonic acid gas.
1:23 do. aqueous vapour at 47° Fahr.; barom. 29°5 in.
78°35 do. nitrogen, (being the ordinary quantity in 100
parts of air that contain 1°23 parts
100°05 of aq. vap.)

Consequently there was no error in the abstraction of the
carbonic acid.

Feb. 19. Air respired into a bag, at 9} a.m.
110°5 parts, became 105'5 .*. 4°52 per cent. loss.
124°33 do. do, 119°33 .. 4°02 do.

2) 8°54
. average loss = 4°27 per cent.
which, corrected for tension, will be 4°38 per cent.

100 parts taken from the same bag over mercury. Baro-
meter at 29°5 inches, and temperature 47° Fahrenheit.

At 11 a.m. a piece of caustic potassa was introduced, and
after a lapse of 61 hours it was abstracted.

5 parts had been absorbed, the thermometer being
47° Fahrenheit, and the barometer standing at 29°65 inches.
The residue

95 parts; barometer at 29°65 inches, are equal to

95°48 do. do. at 29°5 inches,
consequently, only 4°52 parts of the original quantity had
been absorbed, which will include both the carbonic acid gas
and the aqueous vapour. Now as the aqueous vapour at this
temperature and pressure would be 1°23 per cent. there will
remain only 3:29 for the carbonic acid gas; a result which
shows some error in the experiment, but still tends to prove
that the abstraction of the carbonic acid gas by the means
adopted throughout these experiments, viz. by a long and
comparatively wide tube with lime-water as the reagent, are
not less efficient than a small and closely graduated tube with
caustic potassa for the reagent, even although the latter be
employed over URE

Having no ostensible reason for mistrusting my previous
experiments, I began to reflect upon the probable sources of
error in those of Messrs. Allen and Pepys; and here I will
detail the most important circumstances attending their re-
searches upon the subject in question.

Ist. Their experiments appear to have been made with

412 Mr. Coathupe’s Experiments on the Products

great care, with every reasonable precaution, and with
the honest intention of reporting the truth undisguised.

2nd. Their apparatus was good of its kind. It belonged to
the laboratory of the Royal Institution.

3rd. Their reagent was lime-water.

4th. Their eudiometer consisted of a tube containing one cubic
inch, graduated into 100 equal parts.

5th. The time required for obtaining their average supply of
respired air was generally from 10 to 11 minutes.

6th. The operator’s ordinary respirations were 19 per minute,
but during the period necessary for obtaining the quan-
tity of respired air upon which Messrs. Allen and Pepys
bestowed their attention, they amounted to only 5 per
minute.

7th. All their experiments were made either before breakfast,
or immediately before dinner.

Sth. Their average of “ carbonic acid gas produced by the
process of respiration,” amounted to 8 per cent. upon
the air respired *.

To prove whether there could be any difference in the
quantity of carbonic acid gas produced by protracting the
usual time of natural respiration, two bags were filled, the
one immediately after the other, with air respired as follows:

No. 1. Bag, by respiring 18 times per minute adele
No. 2. Bag, by respiring 4 times per minute
No. 1. Bag. 124°5 parts, became 120°33 .*. loss = 3°34 p.cent.
116°33 do. do. 1192°33...do. = 3°43 do.
1198 do. do. 115°66.*.do. = 3°45 do.

3)10°22

.. average loss...... 3°41 p.cent.
which, corrected for tension, will be 3°52 per cent.
No. 2, Bag. 110°5 parts, became 105°5 .* loss = 4°52
124°33 do. do. 119°33...do. 4°02 do.

2)8°54

.. average loss = 4°27 p.cent.
which, corrected for tension, will be 4°38 per cent.
Feb. 19th.
Air respired at 9 p.m. Feb. 19th.
No. 1. Bag, filled, respiring 18 times per ae,
No.2. do. do. do. 3 times per minute.

* Messrs. Allen and Pepys’s Researches in Respiration will be found in
Phil. Mag. First Series, vol. xxxii. p.242.—Epir.

>

of Respiration at different Periods of the Day. 413

No. 1. 99°5 parts, became 95°5 .*. loss = 4°02 per cent.
96:5 do. — do. 93°... do. 3°62 ‘do.

.. average loss = 3°82 per cent.
which, corrected for tension, will be 3°93 per cent.

No.2. Bag. 101 parts, became 95°75 .*. loss = 5°20 p.cent.
113°5 do. do. 108° ..do. 4°84 do.
126 do. do. 120 .. do. 5:00 do.

3)15°04

.. average loss = 5:01 p.cent.
which, corrected for tension, will be 5°12 per cent.

These experiments, made during the same day, and at an
interval of exactly 12 hours, the one confirming the other,
show that an increase of carbonic acid gas is eliminated by
protracting the respiratory process, which increase (from the
average of the present experiments) amounted to one fourth
more than the quantity of carbonic acid gas found in natural
respirations.

These results show at once the expediency of reducing the
quantity of carbonic acid gas obtained by the experiments of
Messrs. Allen and Pepys by one fifth part. ‘The 8 per cent.
will then become 6°4 per cent.

Considering then that Messrs. Allen and Pepys’s opera-
tions were carried on at periods of the day in which I have
shown the respiration to contain its maximum quantity of car-
bonic acid gas, viz. before breakfast, and immediately before
dinner, and that, although the absolute volume of respired
air upon which they operated was very considerable, yet it
was the volume obtained at one period of the day; and that
although their experiments upon this large volume of air
were very numerous, yet the volumes themselves were not
renewed above thrice; it appears that we may rely upon
their demonstration that the air which they examined would,
if respired in the natural manner, have contained 6°4 per cent.
of carbonic acid gas, which quantity is almost the maximum
that occasionally occurs at the most favourable periods for its
production.

Having very many times examined the air respired by other
individuals, I have never yet met with a single instance which
did not accord with the averages already detailed.

414 Dr. Thomson and Mr. Richardson on the

From my own observations, and from the experiments of
others, the following details connected with this subject may
be faithfully relied on, viz.

Ist. The average number of respirations made by most adult
healthy individuais (varying from 17 to 23 per minute)
may be stated as 20 per minute.

2nd. The average bulk of air respired at each respiration
made by such individuals (varying from 14 to 18 cubic
inches) may be stated as 16 cubic inches.

3rd. The average daily amount of carbonic acid gas found
in the air respired by such individuals (varying at its
extremes from 1°9 to 7°98 per cent.) may be stated as
4 per cent.

Hence 460800 cubic inches, or 266°66 cubic feet of air
pass through the lungs of a healthy adult of ordinary stature
in 24 hours, of which 10°666 cubic feet will be converted into
carbonic acid gas, = 2886:27 grs. or 5°45 ounces avoirdupois,
of carbon. ‘This gives 99°6 grs. of carbon per hour, pro-~
duced by the respiration of one human adult, or 124°328
pounds annually; and if we multiply this by 26} millions
(being the calculated population of Great Britain and Ireland
for the year 1839) we have 147,070 tons of carbon as the
annual product of the respiration of human beings at present
existing within the circumscribed boundaries of Great Britain
and Ireland.

Hence also the maximum quantity of fresh atmospheric air
that can possibly be required by a healthy adult during 24
hours, even supposing that no portion of the air respired
could be again inspired, will not exceed 266°666 cubic feet.

Wraxall, near Bristol, CuHarRLES THORNTON CoATHUPE.
Feb. 1839.

LXI. On the Decomposition of Amygdalin by Emulsin. By
Rosert D. Tuomson, M.D., and Mr. Tuomas Ricuarp-
soNn.*

G OME years ago Robiquet ard Boutron-Charlard showed

that volatile oil of bitter almonds and prussic acid, which
are obtained by the distillation of bitter almonds, do not exist
naturally in the almonds but result from the process. They
further ascertained, that when milk of bitter almonds, formed
by triturating almonds with water in a mortar is treated with
strong boiling alcohol, on cooling white crystals are depo-

* From the Annalen der Pharmacie, Band xxix, Heft 2nd, Feb, 1839;
and communicated by Mr, Richardson.

7)

Decomposition of Amygdalin by Emulsin. 415

sited, which separate in larger quantity on further cooling.
To this substance they gave the name of amygdalin. \ Liebig
and Wohler have determined this body to be an amide of
amygdalic acid represented in the following formula:

Nz Ox Hy Oz + H, 03.

Subsequently the investigation was continued by WGhler and
Liebig, who observed that when a solution of amygdalin is
brought into contact with milk of sweet almonds, a most
remarkable and peculiar action takes place: prussic acid and
oil of bitter almonds are formed, as in the instance already
mentioned, when milk of bitter almonds is distilled without
the artificial addition of amygdalin. Besides prussic acid and
oil of bitter almonds there is also formed sugar, which may
be decomposed by fermentation. ‘The solution after the ter-
mination of the fermenting process affords a strong acid re-
action, which is not produced by acetic or any other volatile
acid. When alcohol is added and the solution is concen-
trated, thick white flocks are precipitated, which obviously
contain no emulsin, because when dissolved in water they
have no action upon amyedalin. From these and other pro-
perties the flocks would appear to be gum. The phzno-
mena exhibited in the reaction described, which have been
termed catalytic by Berzelius, resemble in great measure
those which take place in fermentation, and their investigation
promises to throw great light upon some of the most import-
ant processes of the vegetable and animal ceconomy.

With the view of assisting in the elucidation of the subject
we have commenced with the examination of the essential in-
gredients of the milk of sweet almonds which has been termed
emulsin. ‘The process by which we obtained the substance was
as follows. Sweet almonds were triturated in a mortar, and
small portions of water were gradually added until a milky
fluid was obtained. This fluid was mixed with four times its
volume of ather, and frequently agitated so as to effect an
intimate mixture. A clear fluid gradually separated at the bot-
tom of the stoppered bottle in which the experiment was made,
and which at the end of three weeks was drawn off by means
of a siphon. The fluid was passed through a filter, and to
one half of the clear solution a large quantity of alcohol was
added, which produced a copious deposition of white flocks
which were emulsin. From the other half the emulsin was
separated by bringing the solution to the boiling point, when
it precipitated in flocky coagula. The emulsin precipitated
by alcohol was carefully washed with the same fluid, and then
dried over sulphuric acid in the yacuum of an air-pump to

416 Mr. Trull on the Egects of Light and Air in restoring

avoid the effects of heat. In this state it possessed the fol-
lowing characters; it is a white powder, destitute of taste
and smell, soluble in water, insoluble in alcohol and zether.
When subjected to analysis in the usual way, the following
results were obtained :

I. 3485 grms. gave ‘618 grms. CO, and *2445 grms. HO.
II. :3625 grms. ,,- °6365 ,, sa, tnd *2505+> 4, Se
The relation of the carbon and azote was as 3C to1 A.
From these results we have

I II.

Carbon ...se0e06 49°025 48°555
Azote eeeeeeeee 18°910 18°742
Hydrogen...... 7°788 T'677
OXyZeN seeveveee 24°272 25:026

100:000 100:000

The fact of the existence of the substance operated on in the
almonds appears to be established by its acting on amygdalin in
the same manner as the milk of almonds alluded to in the com-
mencement of the paper. After numerous trials with various
reagents, its most distinguishing character was elicited by the

hzenomena exhibited when boiled with barytes. During
the whole of the boiling, which was continued above six hours,
ammonia was slowly and continuously disengaged. ‘Through
the solution a current of carbonic acid gas was passed, and the
whole filtered; the clear solution was evaporated to dryness,
and the residual salt, which contained a large quantity of
barytes, possessed a strongly bitter taste; thus leading to the
conclusion that emadsin is an amide; and that the salt formed
by the action of barytes is a compound of barytes with an
acid which we propose to term emulsic acid. The relations
of emulsin to albumen, fibrin, and casein, &c. will form matter
for subsequent investigation.

LXII. On the Effects of Light and Air in restoring the faded
Colours of the Raphael Tapestries. By Mr. Tru; com-
municated by Michael Faraday, Esq., D.C.L., F.R.S.

To the Editors of the Philosophical Magazine and Journal.

GENTLEMEN, April 21, 1839.
you probably remember an-exhibition in July last of cer-

tain Raphael Tapestries in the Haymarket, and the
extraordinary effect the exposure to light and air had had in
restoring and altering colours which had faded during cen-

the faded Colours of the Raphael Tapestries. 417

turies of exclusion from these mighty agents. I have received
letters from the proprietor Mr. Trull, and if you think parts
of them worth publication at this time, when the action of
light in the service of the fine arts is so much dwelt upon,
they are entirely at your service.

I am, Gentlemen, yours, Xc.,

April 21, 1839. Micwaert Farapay.
To Professor Faraday.
Sir, Warwick-row, Coventry, March 12," 1839,

The interest you took in observing the changes of co-
lour in the Raphael Tapestries, after being exposed to
light in London last July, made me anxious to communicate
to you the extraordinary effects since produced, by the sim-
ple means suggested by yourself and other scientific gentle-
men, of a more perfect exposure to light and air, which have
for the last seven months been obtained, in a finely situated
factory here.

I feared to trespass on your valuable time, but could not
resist, after hearing of the great public interest now excited
by the new process, called, I believe, “ sun painting.”

Light and air have done wonders for my tapestries, in
dispelling the damp, clearing up the colours, and reproducing
others, obscured by the effects of many years’ close packing
up in boxes. I regret not to be able to make scientific re-
marks on the progress of the recovery, which others ac-
quainted with chemistry might have done.

The results cannot fully be appreciated but by those who
recollect the work when up in London, where the first effects
of change unexpectedly commenced.

The greens had all become blue; you, Sir, anticipated a
return to the original tints, which has, almost throughout,
taken place.

The robes and full colours generally had become dull and
heavy; this has gradually gone off, and left a brilliancy of
colour and beauty of effect hardly to be excelled. The gold
also, as you hinted, has become more clear and bright.

The flesh parts of the figures, which had become pallid,
almost to white, have recovered the high tint and deep sha-
dow, and the strong anatomical effect of Raphael.

A renewed freshness now reigns over the whole, and the
clearing up of the light in many of the landscape parts is
most extraordinary, giving a depth and breadth the cartoons
themselves do not now convey, particularly in the Keys to
St. Peter, St. Paul at Athens, and The Death of Ananias;

Phil. Mag. 8.3. Vol. 14. No. 91, June 1839. 2E

418 Restoration of faded Colours in the Raphael Tapestries.

where extensive landscape, ranges of buildings, and foliage
have sprung up, like magic, on parts quite obscured when
up in London eight months back, much of which is either
worn, or torn out of Raphael’s patterns at Hampton, and
painted over, and known only through the means of these
Leo Tapestries.

I should have much pleasure in giving you any further in-
formation on the subject I am capable of, or in showing the
works to any persons taking an interest in them.

I am, &c. Wm. TRULL.

Coventry, April 17, 1839.

My former letter in regard to the extraordinary changes
the Raphael Tapestries had undergone the last seven months,
use as you think proper. I regret not being able to give youa
scientific description from the first, and the progress; and the
absence of a gentleman acquainted with the chemical effects
of light and air, to have noted the changes, is much to be
regreted both for science and art. The works themselves be-
ing unique, and of above three centuries, so placed for so
many years in continued damp to effect such mischief to the
colours, are circumstances never to occur again.

Some colours entirely changed, others in confusion and
apparently gone, yet by the mere effects of light and air,
slowly and quietly resume the chief of their original
tints! Flesh reappears, hair on the head starts up; the grand
muscular effect and unique power of expression, only found
in Raphael and Michael Angelo, are finely developed where
a few months back appeared a plain surface! Here are the
works, and the facts may be now ascertained.

I have applied to the directors of the British Institu-
tion, Pall Mall, to permit one or two of these Tapestries to
be exhibited with the old masters in June; thus those who
saw them last year, may be able to see what they now are,
and both science and art may be served; for a comparison has
never yet been made, since the Cartoons were repaired and
painted upon, with the tapestry.

I think, Sir, you will recollect my subject of the stoning
St. Stephen, the large masses of blue cloud-like appearance
hanging about and over Jerusalem: these have nearly disap-
peared, and mountain scenery taken the place! ‘The olive
grove, which only showed a few trees in front all blue, and a
heavy blue-like curtain was over all of the grove ; the curtain
has disappeared, and a fine deep grove is now seen; the natural
green and mossy bank have nearly taken their original state ;
fresh lights keep breaking out and showing even deeper in the

Professor Forbes on the Colours of the Atmosphere. 419

grove! and throughout the works, the original lights are
working their way, from the heavier colour.
I remain, Sir, yours, &c.,

Wm. Truitt.

LXIII. The Colours of the Atmosphere considered with re-
ference to a previous Paper “On the Colour of Steam
under certain circumstances.” By James D. Forzes, Esq.,
F. R. SS. L. & Ed., Professor of Natural Philosophy in the
University of Edinburgh.*

ty the following Paper, it is proposed to illustrate more fully

the hint explanatory of certain atmospheric colours, given
in a notice of the remarkable red hue of condensing steam,
communicated on the 21st January. Since that time, I have
examined with care the principal authors who have adverted
to the subject of the colour of the sky generally, and of the
redness of sunset in particular; and since, in the course of
that research, I have found much to confirm, and little to
modify, the view which I have already taken of the subject, I
hope that the present Paper may be considered as a fit ap-
pendix to my former experimental notice. It will be recollected
that in it I stated the singular fact, that steam does not pass
at once from the state of invisible pellucid vapour to that of a
misty white cloud, such as issues from the spout of a tea-kettle;
but that an intermediate stage occurs, in which it is coloured,
even very highly, giving to transmitted light a hue varying
from tawny yellow up to intense smoke-red. I then observed,
that, since this phenomenon does not require steam of high
tension for its production, it is very probable that the tints of
sunset and of artificial lights seen through certain fogs, may
be owing to the absorptive action of watery vapour in this
critical condition.

Eberhard, a writer of more than sixty years ago, states that
the multitude of opinions of authors on the colour of the sky
alarmed him when he came to analyse them; and as, since
his time, these have perhaps been doubled, some idea may be
formed of the labour required to collect and classify the scat-
tered notices which are to be found in special treatises, acade-

* From the Transactions of the Royal Society of Edinburgh, vol. xiy.,
part 2, p. 375; having been read before the Society on the 4th of February
1839. The previous Paper, read before the same body on the 2lst of
January, will be found in L. and E. Phil. Mag. for February, pres. vol.

. 121. A letter on the same subject addressed to Professor Forbes, by
Mir, Webster, Sec. Inst, C, E., se in our number for March, p, 184,

2h2

420 Professor Forbes on the Colours of the Atmosphere.

mical collections, and periodical works, respecting it. The
most copious references I have found amongst German
authors, but these I have, in almost every case, been able
to verify by a reference to the original authorities. The re-
sult has been a reduction to a few of those authors who have
added anything of consequence to a subject which has rather
been one of opinion than of science, until lately; and to still
fewer of those who, by any one original observation or expe-
riment, have added a single mite to the data for reasoning.
The mass of copyists I may pass over in silence, or with little
notice, and thus I hope to be able to reduce into moderate
compass the results of a considerably tedious investigation.

It is impossible to advance any consistent theory about the
colours of dawn, sunset, and clouds generally, without inclu-
ding the fact of the blue colour of the sky. The first notice I
find quoted on the subject by way of explanation, is Leonardo
da Vinci’s*, who attributed it to the mixture of the white solar
light reflected from the matter of the atmosphere, with the in-
tense darkness of the celestial spaces beyond. This doctrine
was also maintained by Fromond, and later by De la Hire,
Funk, Wolff, and Musschenbroek, after the Newtonian theory
of colours should have banished such reasonings from science.
Tt was still later revived, to the disgrace of modern physics,
amongst the chromatic fancies of Gothe+. Otto Guericke
had nearly similar views.

The first trace of a more reasonable doctrine I find quoted
from the writings of Honoratus Fabrit, probably from his
Optical Essays, published at Lyons in 1667, and which must,
therefore, have been independent of Newton’s observations §.
In opposition to the doctrines of Fromond, Fabri attributes
the colour of the sky to the reflection of light, by corpuscular
particles floating in the atmosphere; and Mariotte, about the
same time, seems boldly to have maintained that the colour of
air is blue

Newton’s thoughts on this subject are given, with his cus-
tomary modesty, rather in the form of suggestions than asser-

* Traité de la Peinture, quoted in Gehler’s Worterbuch, art. Aémosphire,

+ Farbenlehre, 1. 59, quoted by Humboldt.

t Eberhard in Rozier, i. 620.

§ Fabri’s Dialogues (1669), of which I have found a copy in the Adyo-
cates’ Library, contain many allusions to the imperfect transparency of the
air, and the foreign particles mixed with it; but I do not find his theory of
the blue colour clearly stated.

|| “On peut croire qu’ii y a des couleurs primitives dans quelques corps,
comme du bleu dans l’air. . . . . . Il semble qu'il y ait du yerd dans
Veau.”—Mariotte, uvres,i. 299, Leide 1717,

Professor Forbes on the Colours of the Atmosphere. 421

tions; and as many writers of the last century have only
reproduced his ideas with slight alterations, it is important to
observe his own exact statement of them. Newton’s opinion
respecting the colours of natural bodies, whatever judgment
we may form as to its universal application, was singularly
ingenious, and well worked out. He had discovered, in the
course of his memorable investigation on the colours of thin
plates, that every transparent body begins to reflect colours
at a certain thickness; that these vary according to definite
laws, as the thickness diminishes, passing through an immense
variety of compound tints, until at length it becomes so thin
(as in the case of the soap-bubble) as to be incapable of re-
flecting any colour at all: the last colour it reflects being
orange, yellowish-white, and finally blue, before they vanish ;
these are called colours of the first order. Now, on this sub-
ject, Newton says, ‘‘ The blue of the first order, though very
faint and little, may possibly be the colour of some substances ;
and particularly the azure colour of the sky seems to be of this
order. Tor all vapours, when they begin to condense and
coagulate into small parcels, become first of that bigness
whereby such an azure must be reflected before they can con-
stitute clouds of other colours. And so this being the first
colour which vapours begin to reflect, it ought to be the
colour of the finest and most transparent skies in which
vapours are not arrived to that grossness requisite to reflect
other colours, as we find it by experience*.” In another pro-
position, he says: “ If we consider the various phenomena of
the atmosphere, we may observe, that when vapours are first
raised, they hinder not the transparency of the air, being di-
vided into parts too small to cause any reflection in their su-
perficies. But when, in order to compose drops of rain, they
begin to coalesce and constitute globules of all intermediate
sizes, those globules, when they become of a convenient size
to reflect some colours, and transmit others, may constitute
clouds of various colours, according to their sizes; and I see
not what can be rationally conceived in so transparent a sub-
stance as water for the production of these colours, besides
the various sizes of its fluid and globular parcels +.”

The theory of Newton, therefore, embraces the colour of
clouds, whether by reflected or transmitted light, as well as
that of the blue sky. He applied a modification of the same
theory to explain the corone round the sun and moont. The

* Optics, Book ii. Part iii. Prop, vii. + Ibid. Prop. y. end,
t Book ii. Part iv. Obs, 13.

422 Professor Forbes on the Colours of the Atmosphere.

air he seems to have believed to be devoid of colour, and the
reflective particles to consist of vapour foreign to it.

The idea of Mariotte of the inherent quality of the sky to
reflect blue light, was next prominently stated by Bouguer,
who further put it in so palpable a form as to have been ge-
nerally quoted since as a complete explanation of aérial co-
lours*. He observes, that as red light penetrates further than
blue (the reason is not mentioned), the latter iswholly reflected,
whilst the former reaches the eye; and this theory was further
improved by later writers, by ascribing superior momentum to
the red rays, and inferior to the more refrangible ones, Smith,
the author of the System of Optics, states the same view, but
with greater clearness. ‘ The blue colour of a clear sky,”
he says, ‘shows manifestly that the blue-making rays are
more copiously reflected from pure air than those of any
other colour; consequently they are less copiously transmitted
through it among the rest that come from the sun, and so
much the less as the tract of air through which they pass is
the longer. Hence the common colour of the sun and moon
is whitest in the meridian, and grows gradually more inclined
to diluted yellow, orange, and red, as they descend lower;
that is, as the rays are transmitted through a longer tract of
airt+;” and so he explains the colour of the moon in eclipses
by the altered light refracted by the earth’s atmosphere.

Next, Euler (1762) maintained the same opinion as to the
blueness of the sky. ‘It is more probable,” he says, “ that
all the particles of the air should have a faintly bluish cast, but
so very faint as to be imperceptible, until presented in a pro-
digious mass, such as the whole extent of the atmosphere,
than that this colour is to be ascribed to vapours floating in
the air, which do not pertain to it. In fact, the purer the air
is, and the more purged from exhalation, the brighter is the
lustre of heaven’s azure, which is a sufficient proof that we
must look for the reason of it 7m the nature of the proper par-
ticles of the air t.”

The Abbé Nollet (1764) attributes the blue colour of the
sky to its reflecting those rays; but, strangely enough, he sup-
poses, that, in order to convey that tint to the eye, they must
previously have come to the earth, been reflected by it, and
stopped in their second transit through the atmosphere. The

* Traité d'Optique, p. 365-368. He likewise explains the coloured
shadows noticed by Buffon.

+ Smith’s Optics, vol. ii. Remarks, 378.

{ Euler's Letters (translation), ii. 507.

Professor Forbes on the Colours of the Atmosphere. 423

colour of the sun in a fog he attributes to the fog stopping the
blue rays, at which time, he says, the atmosphere must appear
blue externally to an observer in the moon*.

A very clever but little known writer, Mr. Thomas Mel-
vill, who died in 1753, aged twenty-seven, has left some in-
teresting observations exactly to our purpose, in a paper
published in the second volume of the Edinburgh Physical
and Literary Essayst. Amongst other acute remarks on op-
tical subjects, after approving of Newton’s theory of the blue
colour of the sky, he objects to his explanation of the tints of
sunset, justly inquiring, ‘“‘ Why the particles of the clouds be-
come just at that particular time, and never at any other, of
such magnitude as to separate these colours; and why they
are rarely, if ever, seen tinctured with blue and green, as well
as red, orange, and yellow?” ‘Much rather,” he adds,
“since the atmosphere reflects a greater quantity of the blue
and violet rays than of the rest, the sun’s light transmitted
through it ought to draw towards orange-yellow or red,
especially when it passes through the greatest tract of air;
accordingly, every one must have remarked that the sun’s
horizontal light is sometimes so deeply tinctured, that objects
directly illuminated by it appear of a high orange or even red ;
at that instant, is it any wonder that the colourless clouds re-
flect the same rays in a more bright and lively manner?” This
he more fully illustrates, and then adds,—“ Does it not greatly
confirm this explication, that these coloured clouds immedi-
ately resume that dark leaden hue which they receive from the
sky as soon as the sun’s direct rays cease to strike upon them ?
For if their gaudy colours arose like those of the soap-budble,
from the particular size of their parts, they would preserve
nearly the same colours, though much fainter when illumi-
nated only by the atmosphere. About the time of sunset, or
a little after, the lower part of the sky to some distance on
each side from the place of his setting, seems to incline to a
faint sea-green, by the mixture of his transmitted beams, which
are then yellowish, with ethereal blue; at greater distances,
this faint green gradually changes into a reddish-brown, be-
cause the sun’s rays, by passing through more air, begin to
incline to orange ; and on the opposite side of the hemisphere,
the colour of the horizontal sky inclines sensibly to purple,
because his transmitted light, which mixes with the azure, by
passing through a still greater length of air, becomes reddish.”
I have quoted this passage, because, so far as it goes, it ex-

* Nollet, Lecons de Physique, vi. 17. 1765.
+ Page 81-89, &c, Edin. 1770.

4.24 Professor Forbes on the Colours of the Atmosphere.

plains with remarkable elegance the actually observed phe-
nomena, and because it exposes the insufficiency of the theory
of iridescent colours to explain the hues of sunset. The theory
of vesicular vapour, or floating bubbles of water as constitu-
ting clouds, was prevalent even at a far earlier period than this.
Leibnitz had supported it in the seventeenth century *, and
had calculated the rarity of the ethereal fluid with which they
were supposed to be filled. Kratzenstein (1740) had, by ac-
tual experiment on the colours which they reflected, attempted
to estimate their thickness by direct measurement, to find their
diameter}. Saussure demonstrated the existence of bodies
apparently so constituted, in clouds themselves: but I nowhere
find that he has applied it to explain their coloration on the
principle which Melvill justly condemns in this passage.
Saussure’s opinion of the blue colour of the sky was, so far
as I can judge, that of Mariotte and Bouguer{, although he
alludes very particularly to bluish vapours as foreign matters
floating in the upper regions of the sky, which he says were de-
cidedly not aqueous, since they did not affect the hygrometerS.
He thinks this may illustrate the obscure phenomena of dry

fogs |

“The memoir of Eberhard of Berlin on this subject] con-
tains nothing to detain us. ‘The author seems to coincide in
the theory ot Mariotte, and spends much labour in refuting
that of Da Vinci.

Delaval’s elaborate Theory of the Colour of Bodies, we
may also rapidly dispose of. He adopts the idea of Fabri, that
the foreign matters suspended in the air become the means of
reflecting blue light, and transmitting red, on the same prin-
ciple as arsenic dispersed through glass. ‘This comparison
to the acknowledged phzenomena of opalescence, is not unim-
portant**.

The greater part of the optical writers of the present cen-
tury have closely followed one or other of those already

.

* Opera Omnia, ii. p. ii. 82. Edit. 1768. ‘Cur vapores eleventur non
spernenda quzstio est, atque inter alia non malé concipiuntur in illis bullze
insensibiles ex pellicula aque et aére incluso constantes, quales sensus in
liquoribus spumescentibus ostendit.”

+ Théorie de l’Elevation des Vapeurs et des Exhalaisons, &c. Bordeaux,
1740. Quoted in Saussure’s Hygrometrie, § 202, and in Kamtz, Lehrbuch
der Meteorologie, iii. 48. The diameter he made ;;‘sy, and the thickness
po id

t Voyages dans les Alpes, iv. § 2083,

6 Hygrometrie, § 355.

|| Ibid. § 372.

§ Rozier, Introduction, i. 618.

** Manchester Memoirs, 1st Series, ii. 214, &c.

Professor Forbes on the Colours of the Atmosphere. 425

quoted. The writer of the article Optics in the 4th edition of
the Encyclopedia Britannica, which was revised by Professor
Robison, gives, as an opinion which he considers new, that of
Bouguer and Melvill, with very little modification or addition.
He assumes the greater momentum of the red ray (deduced,
I presume, from the Newtonian theory of refraction), as the
explanation of its greater transmissibility, and the reflection
of the blue, attributing the colours of sunset to the former,
those of a pure atmosphere to the latter. It would have been
more correct, however, simply to assume the blueness of the
atmosphere for reflected, and its redness for transmitted light,
since we see in differently coloured media, that the assumed
prerogative of the red ray does not hold, being absorbed by a
green or blue glass, whilst the other rays persevere.

Humboldt gives no positive opinion upon the colours of the
atmosphere, or of water*.

It is singular that I have been unable to discover in Dr.
Young’s various writings very positive notices of his opinion
on this subject, though it is probable that he coincided in ge-
neral with the view last stated}. He seems to have leaned
strongly to Newton’s theory of the colour of bodies, though
he was not insensible to its difficulties.

Sir John Leslie very explicitly adopts the theory of air re-
flecting blue light, and transmitting orange, as a full and ade-
quate solution of the colour of a pure sky, and also of the tints
of yellow, orange, red, and crimson, which characterize the
sun’s light when near the horizon}. The important obser-
vation of Sir D. Brewster ||, that the blue light of the sky is
polarized, and therefore has undergone reflection, is conclusive
on that point, although the cause of the peculiarities of the
plane of polarization in different regions of the sky is not easily
explained §.

Sir John Herschel coincides with Newton in considering
the colour of the sky as the blue of the first order, and as one
of the most satisfactory applications of the Newtonian theory .

But the author who, of all others I have met with, supports
Bouguer’s theory of the colour of the sky with greatest full-

* See his Rélation Historique, 8vo, ii. 116, &c.

+ See his Nat. Phil. ii. 321. Compare pages 637, 638, 646, on Newton’s
Theory of the Colour of Bodies.

t Encyclopedia Britannica, art. Metcorology. The same theory is main-
tained in the article Physical Geography by Dr. Traill, just published.

|| On New Philosophical Instruments, p. 349.

Peclet, T'railé de Physique, ii. 307. Brussels edit. ; Herschel on Light,

art. 858, and Quetelet’s Supplement to the French translation,

4] Essay on Light, art. 1143.

426 Dr. Beke on the Alluvia of Babylonia and Chaldaa.

ness and ingenuity, is Brandes, in the article Abendrithe
(evening redness), in Gehler’s Physikalisches Worterbuch *.
He maintains the colour of the sun, and surrounding clouds,
at sunset and sunrise, to be due solely to the colour of pure
air,—a doctrine which he supports by many striking argu-
ments. The presence of vapours, he observes, is always in-
dicated by a dull white, mixed with the azure of the sky, and
the complementary colour of that white which should belong
to the transmitted ray can never be red. On the contrary,
he says, the colour of the sun seen directly through clouds,
when on the meridian, is always white, and the effect even of
so strong a mist as to render his disc easily viewed by the
naked eye, is to give it the appearance of a silver platet,
The beauty of the sunset, he further observes, is in exact
proportion to the purity of the atmospheric blue during the
day; and the only reason, he asserts, why the sun appears to
set red through vapours, is because his light is by them so
much diluted that the colour can be more distinctly perceived.
The colour of elevated clouds, at some distance from the ho-
rizon, he imputes (as Melvili had done) to the great space of
air which the light must traverse before it reaches them, and,
after doing so, before it falls on the eye. The green colours
of the sky he attributes, as Leslie and most other writers have
done, to the reflected blue light mixing with the transmitted
orange. ‘This theory was never so ably handled.

[To be continued. }

LXIV. On the Alluvia of Babylonia and Chaldaa. By
Cuartes T. Bexe, Ph. D., F.S.A.

To the Editors of the Philosophical Magazine and Journal.

GENTLEMEN,

ig is now two years since I last addressed you on the ad-

vance of the land at the head of the Persian Gulf {; I am
now induced to revert to the subject by the recent publication
of Mr. Ainsworth’s ‘* Researches in Assyria, Babylonia, and
Chaldza,” (London, 1838), in which work are given the geo-
logical results of the Euphrates Expedition under the able
conduct of Colonel Chesney.

Without going into the details of Mr. Ainsworth’s investi-
gations, it is sufficient to say that he determines “ so far, the

* Vol. i. p. 4. &e, 1825.
+ Gehler’s Physikalisches Worterbuch, vol. i. p. 6, Note.
{ See Lond. and Edinb. Phil. Mag. for July, 1837 ; voi. xi. p. 66.

Dr. Beke on the Alluvia of Babylonia and Chald@a. 427

outline of the sea of Oman, or Gulf of Persia, at the earliest
times of authentic history, [7. e. as appears from the context,
at the time of Nearchus’s voyage,| as to trace it from the
territory of Ghorein, by Jebel Sinam or Teredon, Zobeir,
Spasinus Charax, and the Vallum Pasini in an undefined
line across Dorakstan or Ka’ban, to the Arosis or Indiyan* ;”
and he also “ finds evidence of the former existence of a lake,
formed by the junction of the Tigris and the Choaspes or
Euleus, and extending from the neighbourhood of Diridotis
to that of Aginis (Haw4z), and bounded to the north by the
territory of Ampé, Aphlé, and Apamea, and to the south by
that of Mesene and Charax+.” His conclusion as to the
advance of the land in this locality generally, is, that it may
be calculated at about 30 yards per annum ; which gives about
35 miles of increase since the time of Nearchus, and about
double that quantity, or 70 miles, for the entire advance since
the earliest post-diluvian periods {.

Hence it follows, as Mr. Ainsworth himself states§, that
** Nearchus’s fleet must have taken a diagonal or north-west
course across the country which now forms part of Dorakstan
and Mahersi;” a conclusion in direct opposition to the opi-
nion entertained by Dr. Vincent, that * the pilot on board
Nearchus’s ship steered exactly the same course as M¢Cluer’s
Karack pilot 2000 years afterwards||;” and a sufficient con-
firmation of the correctness of the former of the two proposi-
tions advanced by me in my dispute with Mr. Carter, namely,
** that, within the period of history, an advance of the land
upon the sea has taken place of sufficient importance to affect
materially the geography of the localities in question ],”—
‘and such, therefore, as to render the descriptions of ancient
writers inapplicable to the present state of the country **.”

The other of my propositions was, ‘that, within the same
period of history, the advance of the land upon the sea has
been so great as (independently of all other arguments,) to
warrant my conclusion with respect to the non-identity of the
Babylon of Nebuchadnezzar and the Babel of Genesis}+.” On
this point Mr. Ainsworth differs entirely from me; inasmuch
as he makes the total advance of the land since the Flood
only about 70 miles, whereas according to my hypothesis it
must have been at least four times as much.

* See Lond. & Edinb. Phil. Mag., vol. xi, pp. 193,194. + Lid.
t See p. 194. § p. 187,
| Commerce and Navigation of the Ancients in the Indian Ocean,
vol. i. p. 466 ; and see Lond, and Edinb. Phil. Mag,, vol. v. p. 248.
4 L. & E. Phil. Mag., vol. viii. p. 506, ** Ibid. vol. ix. p. 42,
tt Lbid., vol. viii. p. 506.

428 Dr. Beke on the Alluvia of Babylonia and Chaldca.

With all due deference to the opinions expressed by Mr.
Ainsworth, and with a full consciousness of the great advan-
tages which he has derived from an actual acquaintance with
the localities in question, I will here merely raise one princi-
pal objection to the conclusion come to by him as to the ad-
vance of the land since the Noachian deluge being no more
than 70 miles, from the circumstance that one of the main

. grounds for his thus restricting it, is the assumption, in the very
outset of his arguments*, that the site of Babylon is actually
identical with that of the tower of Babel; an assumption
which leads him into difficulties not easily to be surmounted.
I will briefly explain how this is.

Mr. Ainsworth states as the result of his observations, that
* the last of the deposits by transport that is met with in that
portion of the basin of the Euphrates which presents a rocky
soil, is at a very short distance to the south of Hil+”, and
that *‘ the limits of the al/uvia are met with to the north in
low hills and undulating land of tertiary rock formations,
which advance to the banks of Euphrates at Mesjid Sanda-
biyah, across the river about eight miles above Felijah or
Anbar, and at the Pyle of Xenophon rise in low hills above
the plain of Babylonia, and towards Tigris are lost in the
plains traversed by the Median wall{.’ This is, in fact,
giving the tract of country actually formed by the alluvial
deposits of the river almost the very same extent northward
(z.e. above 70 miles to the northward of the ruins of Ba-
bylon, )as is conjecturally laid down in the map prefixed to my
** Origines Biblice.” Further, the western and eastern limits
attributed by Mr. Ainsworth to these alluvia§ apparently
approach also very nearly to the limits given to them in
my map ||.”

* p. 104. t pp. 103, 104. t pp. 1125113: § p. 113.

|| The two severest and most detailed critiques of my Origines Biblice
are from the pens of the well-known rationalist Dr. Paulus, in the Heidel-
berger Jahrbucher for January 1835 (new series, vol. ii. pp. 43—61),
and the Rev. H. H. Milman in the Quarterly Review for November 1834
(vol. lii. pp. 496—519). Both these writers defend the traditional identi-
fication of Babylon with Babel! The latter says (p. 504), with reference
to the above subject, “ Mr. Beke’s is the first attempt to reconstruct
history on the principles of the young science of geology; but if historical
speculation allies itself with science, it must submit to all the severe rules
of scientific disquisition. Jt must take nothing for granted; it must not
be contented with sketching on a map the probable line of coast which
it may choose to assign to the Persian Gulf. or any other body of water.
It must not only enlarge, if necessary, the borders of the received chrono-
logy, but be in possession of accurate geological information as to the
nature of the dry land which it thus converts into sea. When Mr. Lyell,
or some other equally observant and highly gifted geologist, shall have sur-

~~ ae 3

Dr. Beke on the Alluvia of Babylonia and Chaldea. 429

Having then shown that “ there occurs, at a rough calcu-
lation, a distance equal .to, at the least, 70 miles, between the
limits of the latest deposits by transport and the plain of
Babylon*,” Mr. Ainsworth proceeds toargue, that ‘‘as the site
of Babylon is separated by a wide extent of deposits of a dif-
ferent nature from the latest deposits by transport which belong
to the basin of the Euphrates, it is evident that it is impossible
to reconcile the supposition of these latest deposits by trans-
port being identical with the Noachian deluge, and of the
deposits which intervene between them and the soil of the
Tower of Babel, having been deposited in the short interval
of time between the Deluge and the dispersion of man-
kind +.”

He therefore concludes, that “the alluvium of the Eu-
phrates divides itself distinctly into that which was ante-Ba-
bylonian (being also ante-Noachian) and that which is post-
Babylonian; and the comparatively large extent of ante-Ba-
bylonian alluvium contains whatever matters the great cata-
clysm deposited upon the surface of the earth t.”

But in coming to this result, Mr, Ainsworth does not ap-
pear to have considered a further conclusion which must
necessarily follow from his premises. It is, that if the al-
luvial deposits of the basin of the Euphrates, consisting, as
he informs us, of “clays remarkable for containing an ex-
cess of chloride of sodium or marine salt §,” and extending
from the neighbourhood of Felfijah as far as the sea “ to the
exclusion of all other formations ||,” be partly of ante- and
partly of post-Noachian origin, then the Noachian deluge it-
self has, in point of fact, left no intervening traces whatever
of its separate existence; and as such an event, let it have
originated as it may **, could not possibly have happened with-
out leaving traces, and those strongly marked ones, of its oc-

veyed the whole of this tract, and, on his geological responsibility, shall
have, established we will not say, but, found reasonable grounds for con-
jecture, that at the date assumed by Mr. Beke the sea did advance so far
inland, we shall bow to his authority.”

It is therefore most gratifying to me to be able thus to appeal to Mr.
Ainsworth as an authority for the fact that the alluvial deposits do actually
extend so far inland as I had asserted. ‘Their date is now the only point in
question.

* p. 105.

t pp. 104, 105.—Mr. A. accordingly considers these latest deposits by
transport to be the remains of a cataclysm anterior to the Noachian de-
luge. See p. 101. t p. 107. § p. 105. || p. 106.

** Mr. Ainsworth cites without disapprobation my construction of the
Hebrew words “ fountains of the great deep,” as meaning the “ clouds ;”
whence J attribute the Flood to rain alone, See Orig. Bibl,, p. 319 et seq.

430 Dr. Beke on the Alluvia of Babylonia and Chaldea.

currence, to say that it has left no marks of its separate ex-
istence is tantamount to saying that it had no existence at all.

That this is not Mr. Ainsworth’s intention is evident; and
yet it is only a corollary inevitably resulting from his argu-
ments. Hence I feel persuaded, that upon consideration he
will admit that the whole of the alluvial deposits of Babylonia
and Chaldza, being of the same formation, without the inter-
vention of the remains of any cataclysm, and proceeding from
causes which are at the present day still in active operation at
the mouth of the Euphrates, must necessarily have originated
altogether since the Noachian deluge. If this be conceded,
then Mr. Ainsworth’s own arguments * go to prove that the
distance of 70 miles between the commencement of the al-
luvia and the site of Babylon, could not have been formed in
the period between the Deluge and the erection of the Tower
of Babel, and consequently that the site of the former cannot
possibly be identified with that of the latter; and when once
this identification is done away with, and the simple historico-
geological question is left free from the clog placed on it by
the locality traditionally attributed to the Tower of Babel, I
have every reason to expect that Mr. Ainsworth will see suffi-
cient grounds for altering his opinion with respect to the
rate of the advance in former days of the alluvial deposits
upon the sea.

That all the historical evidences are in favour of separating
the Babylon of Nebuchadnezzar from the Babel of Genesis, has
been, I apprehend, already sufficiently shown by me in the
pages of your Journal.

I should have wished to come here to a conclusion; but
before doing so, I am, however unwillingly, compelled to
advert to another subject.

Before proceeding on his Expedition to the Euphrates, Co-
lonel Chesney was so kind as to assure me that the opinions
expressed in my Origines Biblice with reference to the coun-
tries he was going to visit should receive every attention, and
from the frequent reference to my writings made by Mr. Ains-
worth, I conclude that if that gentleman was not already ac-
quainted with my work it was placed in his hands by Colonel
Chesney.

I will not think of complaining that in every instance in
which Mr. Ainsworth has found it expedient to refer to me,
with a single exception, that with respect to the cause of the
Deluge, in p. 107, it has been only to differ from me in opi-
nion t+. Neither will I attempt the invidious task of seeking

* p. 105. } See pp. 58, 105, 126, 149, 160, 190.

Dr. Beke on the Alluvia of Babylonia and Chaldea. 431

how far the opinions enunciated by me might, not unreason-
ably, be presumed to have given rise to the expression of
similar views, or to the consideration of the same subjects on
the part of that gentleman: I am even willing to suppose that
such coincidences as may exist are accidental. But I cannot
do otherwise than express my regret that in one particular
instance, in which he has done me the honour to adopt not
merely my opinions but actually my words, reference should
not have been made to the source from which they were de-
rived. The passage in question, as given by us both, is as

follows:

“In making the foregoing
calculation [as to the compara-
tive advance of the land in the
Adriatic Sea and in the Per-
sian Gulf,| it has been as-
sumed that the circumstances
are similar in both cases: this,
however, is not precisely the
case. The Adriatic is a gulf
in a tideless (or almost tide-
less) sea: the rise and fall of
the tide at the head of the
Persian Gulf is (I believe,) as
much as 8 or 9 feet at spring
tides. From the effect, there-
fore, of the tide, and also from
that of a current which sets
across the head of the Persian
Gulf from east to west, the
accumulation at the mouths
of the rivers would doubtless
be checked, and a portion of
the alluvium would be carried
east [west|-ward and south-
ward, and be dispersed in
those directions over the bot-
tom of the gulf. That such
is actually the case is shown
by the chart of this gulf lately
constructed by the officers
employed in its survey by the
East India Company; from
which it appears, that whilst
along the north-eastern or
Persian side of the gulf the

“¢ In order to form even an
approximatiye opinion upon
the amount of time which the
alluvial formations of Baby-
lonia, Chaldaea, and Susiana
have occupied in their depo-
sition, all the various circum-
stances of their origin must
be taken into account.

‘The first and most im-
portant of which is, &c. &c.

* Fifthly, the nature of the
waters which receive these al-
luvial deposits. The rise and
fall of the tide at the head of
the Persian Gulf is as much
as nine or ten feet in spring-
tides. There is, besides, a
constant current which sets
across the head of the gulf
from east to west; the accu-
mulations at the mouth of the
rivers hence meet witha check,
and a portion of the alluvium
is carried to the westward
and southward, and dispersed
over the bottom of the Gulf;
that such is actually the case,
is shown by the chart of the
gulf lately constructed by the
officers employed in the sur-
vey by the Honourable the
East India Company, from
which it appears that whilst
along the north-eastern or

432

depth, in great part, exceeds
forty fathoms, along the whole
of the Arabian or western and
southern side it varies from
twenty fathoms to shallows
which are unnavigable, and
which, to all appearance, will
soon rise altogether above the
level of the sea.”—Phil. Mag.
for July 1835, vol. vil. p. 43.

Mr. H. Prater on the Anti-inflammable and

Persian side of the gulf, the
depth, in great part, exceeds
40 fathoms, along the whole
of the Arabian or north-west-
ern side, it varies from 16 fa-
thoms to shallows which are
unnavigable, and which to all
appearances, will soon rise al-
together above the level of the
sea.”— Ainsworth, p. 141.

I am ready to believe that the omission of the reference to
me has been unintentional ; still, in justice to myself, I am
bound to allude to the fact.

Iam, Gentlemen, yours, &c.,
Leipzig, March 23, 1839. Cuar.es T. BEKE.

LXV. Observations on the Anti-Inflammable and Anti-Dry-
Rot Powers of the Subcarbonate of Soda and other Salts.
By Horatio Prater, Esg.*

M GAY-LUSSAC some years ago stated that if paper

+" © be dipped in a solution of phosphate of ammonia and

dried, the znflammabilityt of such paper is destroyed.

I was induced by this observation in the winter of 1836 to
prosecute this subject; and at that period, calico, wood and
paper were kept immersed in various saline solutions for days
together, in order to ascertain the comparative energy of
such solutions in destroying the property of inflammability.
As the object of these experiments was altogether practical,
those saline solutions only were tried which could be obtain-
ed at a sufficiently low rate for general use. Accordingly, for
the phosphate of ammonia proposed by M. Gay-Lussac, the
muriate was substituted; and this was found to have the
greatest effect in destroying the inflammable property of
wood, calico, or paper. Wood should remain a week or ten
days immersed in a saturated solution of it; for calico and linen
twenty minutes, and for paper two or three hours at furthest
is sufficient}. If either of these be dried after such immer-

* Communicated by the Author.

+ By this we mean that the paper cannot now be made to consume with
flame. Held in a burning candle, it is still immediately carbonized and
gradually dissipated.

t Some very thick paper was rendered uninflammable by immersion for
six hours. Of course the time required in all these cases must vary with
the thickness of the materials: but when we are sure that the solution has
thoroughly permeated the texture, we should take it out, as this may be
slightly injured by remaining exposed to the action too long. These ob-
servations in regard to the time of immersion apply equally to subcar-
bonate of soda,

a

———

a

.

Anti-dry-rot Powers of Subcarbonate of Soda, §c. 433

sion, and then put into the flame of a candle, they turn black
but do not take fire, and on being removed frem the candle
they do not continue to keep alight ike tinder, ignited as it
were, but without flame. Solution of muriate of tin possesses
an anti-inflammable property to the same degree. These there-
fore will stand first on the list *,

It is worthy of remark, that neither calico, linen, paper, nor
wood seem to lose their anti-inflammable property by pro-
cess of time; at least I have some specimens in my possession,
prepared in December 1836, which are still as inflammable
as at first. ‘This seems’ in accordance with Prof. Faraday’s
experiments, who did not find the muriate of ammonia to
be volatilizable at the common temperatures of the atmo-
spheref.

But as neither the muriate of tin nor the muriate of am-
monia is sufficiently cheap for extenszve use, we are now to
examine the fixed alkalies in reference to the property under
consideration.

The subcarbonates of potass or soda seem sufficiently effi-
cacious, though not to an equal degree with the salts first men-
tioned. There is little or no difference in the efficacy of either
of these alkalies. They both prevent zzflammability: but
neither of them prevents zgnition if we may so speak, that is to
say, when paper or linen is prepared by them and held in
the flame of a candle and then removed, no flame is communi-
cated, but the ignited part or spark continues to spread
slowly until the whole of the material is consumed. And this
it does, whether the substance be held in one direction, or
another; though of course the ignited margin extends most
quickly when it is held in such a position that it can rise
upward. It is to be observed, that whether calico, linen or
paper be soaked twenty-four hours or a week, in solutions
of the alkaline subcarbonates, makes little or no difference in
reference to this power of ignition. It is hence obvious, that
the muriates of tin and ammonia are more decidedly anti-
inflammables than the subcarbonates of potass or soda; but

{* Mr. Prater does not mention borax, which is one of the most ef-
fectual preservatives of muslin and similar fabrics from inflammation and
rapid combustion.—Ebrr. }

+ Phil. Trans., 1830. Some of the paper prepared by muriate of am-
monia was kept by the author at a heat as great as the hand could bear
(probably from 120° to 140°) for an hour, without being rendered in the
least more inflammable.

+ But the texture is injured by such long immersion, though not ren-
dered more anti-inflammable, as many experiments have decided.

Phil. Mag. S. 3. Vol. 14, No. 91. June 1889. 2F

434 Mr. H. Prater on the Anti-inflammable and

it seems not improbable that these latter may retain their
powers longer *.

As there is little or no difference in the power of these al-
kalies, and as the latter is now very considerably cheaper
than the former, we give it the decided preference.

For practical purposes, the subcarbonate of soda will, ex-
cept in very particular cases, be found sufficiently anti-inflam-
mable; for no great or sudden destruction of property which
had been prepared by its solution could take place. Fire
falling on one of the leaves of a book in a library so prepared,
could scarcely be able to extend itself even through the book
on which it fell; and certainly could not communicate to
other volumes. And whether a child’s dress, or the scenes
of a theatre so prepared were set on fire, there would be little
difficulty in extinguishing it. Although therefore the muriate
of ammonia is a more complete anti-inflammable, its great
expense compared to subcarbonate of soda is a formidable
objection to its general use. Papers saturated with it might
sometimes be used instead of parchment}, where it was the
wish to give the greatest degree of security to the documents
or productions.

In reference to wood, muriate of ammonia seems to have
no advantage over the subcarbonate of soda. When wood,
although cut in the thinnest form, is prepared by the solution
of this alkali, the ignited part will not extend, as we have
observed is the case with paper or linen under the same cir-
cumstances. The subcarbonate of soda, then, is what we
recommend for the preparation of all articles composed of
wood.

But it is fair to consider the grand objection to preparing
wood by immersion in the saline solutions (for muriate of
ammonia is equally liable to this objection with subcarbonate of
soda). The objection alluded to is, that all these saline im-
pregnations are completely removed by immersion in water f,

€ T have stated in the preceding page, that I have specimens of wood,
paper, &c., prepared by the muriate of ammonia in December 1836, which
are still quité uninflammable: the same is the case with those prepared
by potass and soda at the same time. But it is still possible that these
latter may remain uninflammable the longest. I was anxious to know
whether the anti-inflammable power seemed to diminish by time; and as
it has not hitherto, I hope these experiments will be more worthy public
confidence.

+ The reason why parchment is not so inflammable as paper probably
is, on account of its containing more azote.

t It need scarcely be stated, that after the saline matter was removed,
the wood in all cases was found to burn with flame, as usual.

at

Anti-dry-rot Powers of Subcarbonate of Soda, &c. 435

or perhaps still more quickly by immersion in solution of
soap and water. This was the case equally with muriate of
tin, and some other solutions that were tried.

The objection, then, just mentioned will apply to wood

’ that may necessarily be exposed to the rain, or which may

require cleaning by soap and water*. ‘This is the case with
the deck of a ship and the floors of dwelling houses as at
present constructed.

It is however to be remembered that even in these cases
only one surface of the wood is exposed to such action: so
that it seems very doubtful whether the combustibility could
be more than very partially restored by such action of rain or
soap and water. And on the deck of a ship theAnti-fire Pre-
ventive Company’s composition +, or some coarse description
of paint or varnish, might be used to prevent the contact of
rain. ‘The same remark applies to the floors of houses, ex-
cept where the French mode of dry-cleaning and polishing
could be adopted, or where carpets might be used.

But such seem the principal, or the oniy exceptions to the
general advantage to be derived from the adoption of anti-
inflammable wood. A great part of the wood used in build-
ing is placed between the floors, or on the sides of houses, which
are usually painted. Of course in either of these cases wood
prepared by subcarbonate of soda will retain its anti-inflam-
mable properties unimpaired. And indeed with regard to the
floors themselves, if after the manner of the French we paid
more attention to the beauty of these than of our carpets, not
having them except in the ordinary rooms so generally made
of deal, wood prepared after the present suggestions could
be still more extensively employed. Those who object to the

* This remark applies equally to kyanized wood. We havein many ex
periments found the corrosive sublimate to be removed by merely in
mersing such wood in water, or particularly sadé-water, for a few days.
Yet this fact seems quite overlooked by architects, and those concerned
in rendering wood proof against the dry rot by Mr. Kyan’s process.

+ Lately patented. Jn this case it would not be necessary to use the
composition for the roof or sides of the cabin. Great credit is due to
the patentees of this invention for the liberal way in which they made
their experiments before the public, but I should not be satisfied without
further trial that the composition will adhere even to the walls, much less
to the top of a room, when combustion to a certain extent is going on in
theroom. It appears to crack, and consequently to fall off, under the in-
fluence of a tolerably strong heat. If it be not influenced by wet, it
would do probably for the decks of ships and for the floors of dwelling«
houses and public buildings. However, it remains to be seen what effect
much friction would have on it.

Since the above was written a second experiment has been made at
Manchester, said to have been still oa successful,

2K 2

436 Mr. H. Prater on the Anti-inflammable and

use of oak, beech, or any wood susceptible of the dry polish
for their halls, staircases*, dining- and drawing-rooms,
might still, by using painted deal under their carpets, employ
uninflammable wood even for floors, with the certainty that
(as water did not come in contact with them) they could not
lose their powers of resisting flame by time. It is needless to
say, that little expense would be incurred by such process,
as the commonest sort of paint could, if desired, be employed
for carpeted rooms; where oil skin was used, there would
be no necessity for painting at all.

Of course, the preceding remarks, though applicable to all
structures of wood, or partially of wood, are more particularly
so to all offices and premises in which, from the trade pursued,
or the number of documents kept in paper, the risk of fire
is increased. And not only are they applicable to public
and private buildings, but also to ships, and particularly to
steam-boats.

Since this essay is intended for practical purposes, any
minute inquiry into the modus operandi of the salts that have
an anti-inflammable property, would be out of place. But
as the carbonate (bicarbonate) of soda answers equally well
as the subcarbonate (carbonate), it seems probable that these
salts act in diminishing combustion, by the carbonic acid they
contain. Muriate of ammonia probably acts by the ammonia.
It is not perhaps so easy to form a plausible conjecture (for
the above are nothing more) how miuriate of tin acts, for
neither bichloride of mercury (corrosive sublimate), sulphate
of zinc, sulphate of copper, nor sulphate of iron, were found
to have such property.

I shall close this paper by only a few more remarks, and
first in reference to Mr. Benjamin Cook’s patent for render-
ing wood, paper, &c. incombustible (to use his own term)
taken out in 1822.

Mr. Cook used subcarbonate of potass, and likewise em-
ployed an instrument for extracting the sap. It appears pro-

* It seems principally by the staircases that fire communicates from
one story to another. It is of immense consequence, therefore, for per-
sonal safety in case of fire, that these at least in a// houses should be of
uninflammable materials. Hence stone staircases are often very properly
employed: but as these could not be used conveniently in smad/ houses,
any more than the more expensive sorts of wood, deal prepared by soda,
and painted, ought certainly to be substituted, carpet or oil-cloth being
laid down in the middle of the stairs. In this case, of course, as the paint
is never trodden upon, it will remain as long without requiring to be
renewed, as when employed for the sides of rooms; and consequently be
of little or no expense compared to the improvement in the appearance
of a staircase that it affects,

Anti-dry-rot Powers of Subcarbonate of Soda, &c. 437

bable that the expense of Mr. Cook’s process was the prin-
cipal reason of its being little, if at all, patronized by the
public. He was possibly also not aware that water extracted the
alkali: if so, he cannot have given all the essential directions
for the use of the invention. Besides, the extraction of the
sap is an unnecessary and expensive operation, as dried wood
does equally well for soaking in the solution. Nevertheless,
Mr. Cook certainly has the credit, as far as my information
goes, of starting this subject first. And the truth is (although
it may appear unnecessary for me to state it), that I had made
my experiments on the anti-inflammable properties of the
alkaline carbonates and muriate of ammonia at Florence,
many months before I was aware that a patent had ever been
taken out on the subject, being principally urged to them, as
already stated, by M. Gay-Lussac’s observation.

But not only in the present inquiries do I find myself an-
ticipated in some degree by Mr. Cook, but also by M. Durioz
of Paris. This gentleman has taken out a patent in France,
for rendering paper, and various articles of muslin, cotton,
&c.*, uninflammable. He very judiciously recommends that
ladies should have their dresses prepared by the process: we
may add, that such a recommendation seems also very appli-
cable to children, among whom instances of burning to death
from the clothes catching fire are still more frequent than
among adults.

M. Durioz has also especially recommended his invention
to the notice of his government, for the purpose of rendering
the scenes of theatres uninflammable; and the French Go-
vernment, when I left Paris some months ago, was stated by
the journals to have expressed themselves favourable to en-
forcing by law the use of M. Durioz’s prepared scenes. It
would be out of place on the present occasion to comment on
such a law. If, as does not seem improbable, the slight ad-
ditional expense of employing an effectual anti-inflammable
preparation should operate with some stage proprietors or
managers against its use, the justice and even benevolence of
such a law would, it is presumed, be apparent.

As M. Durioz had not sent in his specification at the time
I left Paris, I do not know the preparation he employs. As,
however, I was informed that it was necessary to repeat the
immersion each time the articles impregnated were washed,
it is obvious that M. Durioz has not succeeded any better
than myself in fzing the anti-inflammable preparation in the
tissue, or substance operated on. This seems certainly a

* Wood, however, is not mentioned: I have reason to think, from this
circumstance and others, that the process is not applicable to wood,

438 On the Anti-inflammable Powers of Salts.

grand desideratum ; but probably difficult, perhaps impossible.
At all events, I shall confess that all my numerous experi-
ments on the subject have been unsuccessful *.

It now only remains, in order to conclude this paper, to
state, that it seems probable that subcarbonate of soda pos-
sesses, in addition to its anti-inflammable properties, a power
of preventing the dry-rot. Mr, Cook, in reply to a letter I
addressed to him on his patent, when I became acquainted
with it, states that he has since discovered this to be the case.
I am not aware that he has published any experiments on
this subject; nor do I know whether his opinion be founded
on experiments made by himself or others.

In the mean time I shall state the few experiments I made
in support of such opinion, before I was aware that Mr. Cook
considered the point as decided. They are not at present
sufficient evidence of soda possessing an anti-dry-rot power ;
but I discontinued them after Mr. Cook’s communication,
conceiving he would not have made the assertion without
sufficient evidence.

1, While a slight quantity of mould was visible on a piece
of cream-cheese left for comparison, zone whatever was to be
seen on pieces of the same cheese that had been soaked six-
teen hours either in solutions of bichloride of mercury, mu-
riate of soda, muriate of tin, sulphate of copper, acetate of
lead, muriate of ammonia, or subcarbonate of soda. Yet the
observations were continued rather more than three weeks,
viz. from December the 24th, 1838, toJanuary 15th of the pre-
sent year.

2. When about one-third of saturated solutions of bichlo-
ride of mercury and subcarbonate of soda was added to two-
thirds milk in different glasses, in the former case the milk
remained fluid + for three weeks, free from the slightest smell ;
in the latter a very slight, but not unpleasant smell was per-
ceptible: in neither was there any mould. Yet some of the

* For the information of those females who do not wear dresses
rendered uninflammable, it may be observed, that enveloping them-
selves in the hearth rug or counterpane is the best plan to put out
flame if extensive.

+ I have elsewhere observed (cn the blood) that bichloride of mercury
prevents the coagulation of this fluid,and have pointed out some analogies
between the nature of this action in the blood, and the coagulation of
milk when rennet is added to it. It seems in additional support of these
analogies, that bichloride of mercury does not coagulate milk; and further,
that it actually prevents its coagulation when disposed thereto by the
acescent fermentation. I should have little doubt, that if bichloride of
mercury were mixed with milk to which rennet had been added, no coa-
gulation would take place.

i

M. Plateau’s Answer to Objections, Sc. 4.39

same milk left for comparison in the same room was mouldy,
having a strong cheesy smell, and being of course curdled.

3. Some pieces of meat, unboiled potato, and unboiled cab-
bage stalk, were put into water, and into a saturated solution
of subcarbonate of soda at the same time, viz. in the beginning
of January 1838. It is needless to say, that after a few weeks
the animal and vegetable matter put into water began to grow
putrescent; the piece of cabbage stalk and potato gradually
breaking down and (so to speak) actually dissolving in the li-
quid ; whereas those preserved in soda are even at the pre-
sent time, April 1839, perfect in shape, and almost as hard as
when first put in. It is astonishing that the piece of cabbage
stalk should have remained so hard as it is.

It seems clear from these experiments that subcarbonate of
soda prevents ¢wo kinds of decay or decomposition to which
animal and vegetable matter is subject; first, that kind of
decay which is attended with the growth of mould; and se-
condly, that kind of decay which proceeds further, and is
synonymous with a complete dissolution of particles. Whether
these be but degrees of each other, or be essentially different,
we do not now inquire: it is sufficient for our purpose that
the decay attended with the growth of mould is very ana-
logous to that attended with the growth of fungus, or the rot
(dry-rot, as it appears to be called, but perhaps improperly)
of wood. It seems hence extremely probable that subcarbo-
nate of soda which stops the one, would stop the other; but
to establish this point with certainty, would of course require
that experiments should proceed for years in a fungus pit,—
as that of Woolwich. Nevertheless, the extreme probability
that soda has an anti-dry-rot power must add to its value,
though employed solely as an anti-inflammable.

LXVI. Answer to the Oljections published against a general
Theory of the Visual Appearances which arise from the Con-
templation of Coloured Olyects. By J. Puateau, Professor
at the University of Ghent.

[Continued from p, 340, and concluded. ]

GIR David Brewster also has honoured my theory of acci-
dental colours, by attacking it (see L. & E. Phil. Mag.,
May 1834, page 353). I shall here quote the passage.

* The influence of strong light in rendering the retina par-
tially insensible to red rays, even when these rays fall upon
a part of the membrane which has not been directly acted
upon by the strong light, has been finely shown by the ex-

440 M. Plateau’s Defence of his Theory of the Visual

periment of Dr. Smith of Fochabers *, and I have mentioned
in a former paper + that a stick of red sealing-wax may be
thus made to appear of a dark liver-brown colour.

‘* If we apply the strong light to the“eye when the sensibility
of the retina has been locally diminished by looking at a red
object, a totally insensibility to red light will be produced.
In order to observe this curious result. in perfection, let the
eye be steadily fixed for some time upon a seal of red wax
which reflects white light from all its elevated parts. When
the eye has been so fatigued that it would see a bright acci-
dental green, bring a candle close to the excited eye{, and
so near its axis that the red seal will be seen by rays which
pass near the flame of the candle. When this is done, the red
wax seal will be converted apparently into a seal of black
wax, the lights reflected from its elevations being still di-
stinctly seen. This experiment, when successfully made, af-
fords one of the most remarkable optical deceptions with
which I am acquainted.

** The method now described of eliminating the impression
of the primitive or exciting colour leads us to a very import-
ant determination in the theory of accidental colours. I en-
deavoured long ago to show from analogy, as well as from
the evidence of experiment, that the vision of the primitive
and the accidental colour is contemporaneous, in the same
manner as the fundamental and the harmonic sound are heard
contemporaneously by the ear. That this is the case may be
shown in the following manner. When the eye is fatigued
with the excitation of the red seal, a faint green phosphores-
cent-looking light covers for a while the surface of the red
seal, occasionally overpassing its margin, showing, in the
clearest manner, that the accidental green is seen at the same
time with the exciting red. The effect of this vision of the
green is to make the red appear much paler by its admixture
with it. ‘The red and green tend to produce whiteness; but
as the direct red greatly predominates over the accidental
green, the result is always'a pale red. But when a brilliant
light is brought near the excited eye so as to extinguish com-
pletely the red rays, the phosphorescent green appears alone ;
and thus we have ocular demonstration that the accidental
green is not the light of a white ground deprived of the red
rays to which the eye has been rendered insensible, but is a
colorific impression generated in the retina itself, and super-
added to the whiteness of the ground in the case when the

* Phil. Mag., vol. i. p. 250. 't Ibid. p. 172.
{ In this experiment, the other eye must be coloured.

Appearances from the Contemplation of Coloured Objects. 441

eye is turned from the exciting colour to a white object. These
results are obviously incompatible with the theory of accidental
colours recently published by M. Plateau.”

This is a very abrupt conclusion, and the author will, I
trust, permit me to consider how far it is grounded *,

Before we come to the experiment of the red seal, let us
first examine this other fact related, as we have seen, by Sir
David Brewster, namely, that during the contemplation of a
red object, the colour of this object appears to grow paler, or
to mia itself up with a little white. Certainly, if this fact was
to be admitted in the full extent which the author attributes
to it, iis explanation in my theory would be difficult. But let
us look into the matter more closely. In order to observe an
accidental colour, the process frequently employed is to place
the coloured object which must produce the phznomenon,
upon a white ground. In this circumstance indeed, it seems
that, by a prolonged contemplation, a little white mixes itself
with the colour of that object; and it is, no doubt, in this
manner that Sir David Brewster has operated. But, if we
wish to notice the effect that a prolonged contemplation may
have on the aspect of an object, is it not evident that the latter
must be insulated from every extraneous influence, that it must
be seen alone, or, in other terms, be placed upon a black
ground? Now, in this case, the result is very different: the
colour of the object, instead of growing paler, or blending
itself with white, becomes, on the contrary, darker, or blends
itself with black. The following facts leave nothing to doubt
in that respect.

«If we look,” says Buffon}, “ for a length of time at a
white spot upon a black ground, we shall see the white spot
lose its colour.” Now whiteness which loses its colour, what
is it but whiteness which becomes dark ?

Instead of the white object observed by Buffon, substitute
one of any colour, for instance, a piece of red paper, placing
it as before on a black ground; and, the better to judge the
effect, employ an object of comparison. After having looked
for a length of time at the red paper, the eye being invariably
fixed on the same point, place close to this paper, and with-
out altering the position of the eye, another piece of the same
coloured paper. It is obvious that the image of this latter one

* I have answered that article of Sir David Brewster, above two years
ago, in my detailed memoir, pages 29 and 56 ; but I deem it expedient now
to renew this subject, with the intention of bringing together my answers
to all the objections with which I have become acquainted. I shall besides
consider the matter in a new point of view.

+ Mem, of the Acad, of Sciences of Paris, 1745, p, 153.

442 M. Plateau’s Defence of his Theory of the Visual

falling on another part of the retina, the same may serve to
establish a comparison, and allow you to appreciate the ap-
parent alteration that the colour of the first object has under-
gone. Now this alteration is by this means rendered ex-
tremely sensible: the colour of the paper which has produced
a prolonged impression, appears much darker than that of
the other. It is therefore to be seen that we must attribute
the effect observed by Sir David Brewster to the influence of
the ground upon which the object is placed. I will quote, on
that subject, a fact related by Scherffer : in describing a series
of experiments, the view of which was to verify the effect
pointed out by Buffon, and in which he looked at the object
for a long time, he thus expresses himself (§ 16 of his me-
moir): ‘* When I looked at white spots upon coloured paper,
they seemed slightly tinted in the interior of their periphery
with the colour of the ground. I would not, however, war-
rant that this effect always takes place.” It appears then that
from a prolonged contemplation there may arise, on the part
of the retina occupied by the image of the object, an impres-
sion of the colour which surrounds that object. This can be
ascertained by the following process, which renders the effect
very intense. Place on a sheet of red paper exposed to a
clear day-light, a small square of gray paper of such a tint
as will appear neither paler nor darker than that of the sheet.
Mark a black point in the middle of that small square, and
keep your eyes fixed on this point for a sufficient length of
time. You will shortly see on the square a feeble red hue
manifest itself, which acquires more and more intenseriess,
according as the colour of the sheet appears to darken. Now,
when a red object is placed on a white surface, the feeble tint
of whiteness which seems to blend itself with the colour of
that object, becomes a necessary consequence of the facts
above mentioned. It remains to be shown in what manner
these facts relate to my theory.

If accidental colours are owing to a reaction of the retina,
it must be necessarily admitted that, during the contemplation
of the object, a tendency to the reaction develops itself, that
is to say, that the retina opposes to the action of coloured
rays a certain progressive resistance ; for we cannot conceive
a reaction where there was no resistance. Now, this pro-

‘gressive resistance, or tendency more and more intense to
constitute itself in the opposite state from which results the
sensation of the accidental colour, must necessarily manifest
itself by a gradual falling off in the apparent brightness of
the object looked at. Thus, in the first place, is derived from
my theory, as a necessary consequence, the fact that an object

a. ee ee

ee

a it Ti

Appearances from the Contemplation of Coloured Olyects. 443

insulated from every lateral influence, and contemplated for a
long time, seems to become gradually darker.

During the prolonged contemplation of an insulated ob-
ject, there are consequently two contrary forces in presence
of each other, namely, the action of direct light, and the op-
posite effort of the retina. As long as the first force predo-
minates, theeye feels the sensation of the direct colour, al-
though more or less faded. But if by any cause whatever,
the second force becomes overpowering, then the opposite
sensation manifests itself, and the complementary colour is
perceived. It is thus, for instance, that the experiment of
the red seal is naturally explained: the strong light placed
close to the eye paralyses the action of the red rays emanating
from the seal, and the effort of reaction of the retina being
then overpowering, the green accidental colour shows itself.
In a certain point of view, as may be seen, Sir David Brew.
ster’s theory and mine approach each other; and indeed, in
the first place, they have that in common, that they consider
the accidental colour as owing to an impression of a peculiar
nature, which is spontaneously generated in the organ, and not
as the result of a relative insensibility to certain rays. On the
other hand, according to Sir David Brewster, the accidental
colour unfolds itself on the retina during the contemplation of
the direct colour, and combines itself with this latter; and,
according to me, the opposite effort of the retina, whence re-
sults the negative sensation as soon as that effort ceases to be
counteracted, likewise unfolds itself during the contemplation
of the direct colour, and combines itself in some respect with
this latter, neutralizing it partially. But only, Sir David
Brewster maintains that the combination of the two sensa-
tions produces whiteness, whereas I have shown that, upon
an object insulated from every lateral influence, the result is
on the contrary blackness.

At present it must be ascertained how my theory accounts
for these lateral influences which tend to give the object a
shade of the colour of the ground whereon it rests.

Let us primarily remark that, at the first sight, this fact
seems in opposition with those composing the second section
of which I have spoken at the beginning of this article, and
constituting, on the retina, the passage to the normal state
with regard to space. If, in fact, we bring together the ex-
periments made on the phenomena of simultaneousness by
Rumford*, Meusnier}, Prieur}, &c., and the results ob-

* Philosophical Transactions, 1794,
Me 2 Meusnier’s Experiments are related by Monge (Ann. de Chimie, tome
ii. 1789.) t Annales de Chimie, tome liv.

444 M. Plateau’s Defence of his Theory of the Visual

tained by M. Chevreul*, we shall come to this conclusion;
that, whenever an object of small dimensions is placed upon
a large coloured surface, the small object must take a tint
more or less intense complementary to the colour of this sur-
face +, and not one identical to that colour.

But there is an essential difference between the circum-
stances in which these two phenomena, apparently irrecon-
cilable, are produced; for the one is the result of an zustan-
taneous contemplation, and the other of a prolonged contem-
plation. In fact, by repeating the experiments which relate
to the appearance on the small object of a tint complementary
to that of the surrounding surface, it is easy to verify that this
phenomenon shows itself in an instant with all its intensity ;
and this particularity had already been experienced by M.
Chevreul (see the memoir quoted, page 41.). Now, what must
happen, if the contemplation be prolonged? Since the com-
plementary tint which covers the object results from the Ja-
teral action exercised on the retina by the impression of the
surrounding colour, it is obvious that, if this latter impression
becomes fainter, the complementary tint must undergothe same
change. But the first effect being the necessary result of the
length of the contemplation, the second is nota less inevitable
consequence of it. Thus a prolonged contemplation will
begin by weakening the impression of the complementary
tint. And indeed I have verified this fact, (see my detailed
memoir, page 33,) which can also be easily ascertained by
others. But there is another cause which contributes to pro-
duce this degradation. To make it understood, let us take
an example. Suppose the coloured surface to be red, and
the small object black or gray. Then the prolonged con-
templation will develop, on the part of the retina exposed to
red rays, a contrary action; that is to say, an action tending
to produce the corresponding negative sensation, or the acci-
dental green; but the part of the organ which receives the
image of the small object, and which is consequently alien
to that negative action of the retina, must, according to the
principles of my theory, exercise an effort in an opposite
sense ; that is to say, tending to give the corresponding posz-
tive sensation, namely a sensation of positive red. Now this

* Mémoires de [ Institut, tom. xi. 1832.

f It is only to be remarked, (as I have pointed out in the article of
Annales de Chim. et de Physique which has been before alluded to, agreeably
to the objections of the anonymous author) that im some particular circum-
stances the complementary colour does not extend itself on the whole
surface of the small object, and the middle of this becomes then slightly
tinted with the colour of the ground whereon the object is placed.

—]—_ == - =—_— >

ee

Appearances from the Contemplation of Coloured Objects. 445

latter sensation being also contrary to the green negative tint
which covered the small object at the first instant, there re-
sults from thence a new cause, which must concur with the
former to weaken this negative tint. Much more, if the cir-
cumstances are such that the green negative tint be only faint,
as it commonly happens when we look in a clear daylight, at
a gray object placed on a red ground; then the above-named
cause increasing continually, it must soon completely neu-
tralize the green negative tint, and produce afterwards the
apparition of a positive tint more and more intense. Thus is
explained in the simplest manner the appearing, on the sur-
face of the object, of a tint similar to that of the ground, and
increasing in intenseness with the continuance of the contem-
plation. When the ground is white, the negative action of
the corresponding part of the retina exercises itself at once
upon all the rays which compose whiteness ; and consequently
in the interior of the space occupied by the image of the
small object, the positive action of the organ must produce
the sensation of all those rays combined together, that is to say,
a sensation of whiteness. A small object placed on a white
ground must therefore, by a sufficiently prolonged contem-
plation, appear to take a slight tint of whiteness. In the ex-
ample before mentioned, I have supposed the object to be
black or gray, to show the reasonings in a more simple light;
but we conceive that they are also applicable to an object of
any colour whatever.

I shall now quote new experiments which are very simple,
and confirm the above explanation, in a manner that seems
to me conclusive. ‘They have been repeated with the same
success by other persons.

1. Place on a black surface a sheet of coloured paper, for
instance red, and in the middle of that sheet lay a small
square of black or gray paper marked with a white point.
Fix your sight on this point, till a red tint perfectly visible
shows itself on the surface of the small square. Then, re-
taining this latter in the same place, withdraw suddenly the
coloured sheet, so that the small square thus remains sta-
tioned on the black surface. At that very instant, you will
see the red tint which covers it acquire a remarkable increase
of intensity. In this case, in fact, the surrounding negative
reaction of the retina operating freely, the positive reaction
corresponding to the small square must also operate with
freedom, and thus become much more intense.

2. Instead of withdrawing as above, the sheet of red paper,
cast your eyes rapidly on the ceiling of the apartment, or
cover them completely; then you will see a surface of an in-

446 On the polarized Condition of Platina

tense green, having in the middle a red image equally intense
corresponding to the small square. This fact evidently de-
pends upon the same cause as the preceding one.

I shall terminate by a few words on the analogy admitted
by Sir David Brewster between accidental colours and har~
monic sounds. This philosopher considers as well as myself
the accidental colours as an impression spontaneously gene-
rated in the organ. Now, it is admitted in physics that the
harmonic sound has its origin in the sonorous body itself,
which, besides the principal vibration, executes accessory
ones. Moreover, the accidental impression continues after
the disappearing of the direct impression, and nothing of the
sort manifests itself with regard to harmonic sounds, ‘The
analogy in question appears to me therefore very remote.

The last objections that came to my knowledge have been
raised by Mr. Osann, in the journal of Mr. Poggendorff*. But
that article contains, with respect to my work, such inaccu-
racies, that they disfigure it and render it absurd: here is an
example, of which the reader may judge upon good grounds.
Mr. Osann describes in the following manner my experiment
on the combination of two complementary accidental co-
lours +:

«« Place on a black ground a rectangle of paper, the halves
of which are painted with two complementary colours, for
instance red and green, and each one marked in the middle
with a black point. Jf you look for some time at this coloured
rectangle, and afterwards shut your eyes completely, there will
appear in its place a black image with a red point on one side
and a green point on the other.”

I think it needless to extend further the examination of
this article, and to answer the objections therein contained.

LXVII. On the polarized Condition of Platina Electrodes, and
the Theory of secondary Piles. By A CorrespoNnDENT.

To the Editors of the Philosophical Magazine and Journal.

GENTLEMEN,

AP so much interest has been lately excited by the peculiar
polarized condition into which platina electrodes may be
thrown, the following results, obtained a few months since,

* Annalen der Physik und Chimie, vol. xxxvii. 1836, p. 291, and fol-
lowing.

+ See at the beginning of my present article, on the subject of the
anonymous author’s objections.

ental

Electrodes, and the Theory of Secondary Piles. 447

may perhaps be not uninteresting to some of your numerous
readers. During a long series of experiments upon the
theory of secondary piles, I had occasion to obtain and to
verify the result announced by Mr. Golding Bird in the Phi-
losophical Magazine for November 1838, namely, that the
negative platina electrode of a voltaic arrangement which has
been used in the decomposition of water, will give out less gas
than the positive electrode under the influence of an equal
negative current. I afterwards found,

1. That the negative platina electrode will in certain cases,
and often most unexpectedly, give out more hydrogen than
the positive electrode; that frequently when the two plates
have been together active for some time (both giving out hy-
drogen) in a simple zinc and platina circuit, such as that
described by Mr. Golding Bird, the (originally) negative elec-
trode will evolve Jeast gas in the first half of the experiment
and most in the last.

2. That in this latter condition a delicate galvanometer will
show the negative electrode to be then negative as it was be-
fore invariably pusitive to the other plate.

3. That this condition depends upon the relative cleanliness
of the two electrodes. After scraping bright the surface of
the negative electrode, or the one giving out least hydrogen
in most cases, it gave off still less gas. Ifa similar operation
were performed upon the positive electrode instead, the re-
lative quantities of hydrogen evolved at the two plates ap~
proached nearer to an equality; finally, by using a negative
electrode of which the surface was much discoloured, and a
very bright positive electrode, I obtained the effect of ost
hydrogen evolved from the negative electrode, the latter being
at the same time actually negative to the other plate. Thus,
we may understand how it happens that the secondary cur-
rent from two platina plates which have been repeatedly used
to decompose water as negative and positive electrodes re-
spectively, becomes gradually feebler and feebler, and at last
altogether disappears.

4. That the secondary currents between the two electrodes
is considerable in proportion as the water electrolysed by the
plates has been pure, that is, as the matter evolved upon them
has been purely gaseous. Thus a constant battery was con-
nected during ten minutes with a decomposing apparatus in
which stood the platina plates, and which was filled with a
quantity of acidulated distilled water. When the connexion
with the battery was broken the secondary current was 54°,
estimated by the deflection of the galvanometer needle. A
solution of sulphate of copper was then electrolysed for ten

448 On the polarized Condition of Platina Electrodes.

minutes in the same way. At the end of that time a deposi-
tion of copper was formed upon the negative electrode. A
secondary current of only 15° was obtained. This current
varied in many experiments from 15° to 21°, as that obtained
from the plates in the pure aqueous fluid from 50° to 54°. In
general the secondary current in the sulphate of copper was
only one third of that developed in the distilled water, after
partial electrolysation. When a solution of nitrate of silver
was exposed for ten minutes to the action of the battery, a se-
condary current varying from 9° to 12° was obtained. With
a solution of sulphate of zinc (after the electrolysation of
which a mixture of very impure oxide of zinc, and zine ap-
pear upon the negative electrode) the secondary current was
20°. Even these currents, feeble as they were, I cannot help
attributing solely to the gaseous combinations going on at
those portions of the {platina which remained exposed. The
following experiment shows how very small a portion of the
platina surface which has been active in the electrolysation of
water is sufficient to the production of a far greater secondary
current than any of those above mentioned.

The platina plate to be used as the negative electrode was
divided into two portions, one of which was one eighth of the
whole plate, which itself was not quite half an inch long and
but the fifteenth of an inch in breadth. The two divided
portions were so placed together during a few minutes’ con-
nexion with the battery as to form one electrode; connexion
was broken; a secondary current of 54° was obtained ; seven-
eighths of the plate were then carefully and quickly removed ;
the current instantly fell to 30°; the removed portion was
replaced ; the needle was deflected 50°.

The current resulting from the combination of the gases
oxygen and hydrogen upon the clear platina surface was often
sufficient to decompose water for some minutes. Immediately
that the connexion between the two plates was made this
singular effect was produced, oxygen streaming up from the
negative electrode and hydrogen from the positive.

5. The water electrolysed does not, as some have sup-
posed, assist in the production of a secondary current by the
oxygen which it holds in solution after electrolysation znde-
pendently of that portion upon the surface of the positive
electrode, as may be proved by changing the solution in
which the plates have been active as electrodes of the battery,
or by substituting for the positive electrode after electrolysa-
tion a fresh platina plate. In the latter case there is no se-
condary current. In the former the current will be the same,
whether obtained through the partially electrolysed water,

Geological Society. 449

or through a new alkaline or acid, or saturated saline solu-
tion.

I cannot help thinking that the theory of secondary piles,
of which the functions seem to depend on chemical changes
so very minute, will, when rightly understood, afford the best
refutation of the doctrines of the electromotists. The beauti-
ful experiments of Schcenbein and Matteucci have surely
prepared the way for the establishment of such a theory !

I remain, Gentlemen, yours, &c.,
Je Bs

LXVIII. Proceedings of Learned Societies.

GEOLOGICAL SOCIETY.
President's Anniversary Address: continued from p. 387.

| ies attempting a sketch of the subjects which have occupied the

attention of the Society during the year, I should wish to retain
that distribution of the science of geology according to which I ar-
ranged my remarks in the Address which I had last year the honour
of reading to the Society ; I mean the primary division into Deserip-
tive Geology and Geological Dynamics; the former implying a de-
scription of the rocks of the earth’s surface according to an esta-
blished classification of strata and formations; and the latter dealing
with the study of those general laws and causes of change by which
we hope to understand and account for the facts which Descrip-
tive Geology brings before us ;—in short, the present condition and
the past history of the earth’s crust. But as the laws of permanence
and change, with regard to organized beings, differ very widely from
the dynamics of brute matter, we may conveniently make a separate
study of the relations of organic life to which geology conducts us,
and may mark it by the name Palaontology, by which it is com-
monly known. I will add, that it still appears to me convenient, for
the present, to divide Descriptive Geology into two portions,—the
Home circuit, in which the order of superposition has already been
established with great continuity and detail ; and the Foreign region,
in which we are only just beginning to trace such an order. I shall
also, as before, take the ascending order of strata. According to
this arrangement of the science, I shall venture to bring to your re-
collection a few of the points to which our attention has mainly been
called during the past year.

DESCRIPTIVE GEOLOGY.

1. Home (North European) Geology.—When I stated that De-
scriptive Geology has for its task the reference of the rocks of some
portion of the earth’s surface to an established classification into
strata and formations, it was implied, that the more common employ-
ment of the descriptive geologist must be to refer the rocks which
he examines to some classes already fixed and recognized ; Wut it
could hardly fail to occur to you, that from time to time the leaders

Phil. Mag. 5.3. Vol. 14. No. 91. June 1839. 2G

4.50 Geological Society :—Anniversary of 1839.

in this study will be called upon to execute a more weighty and ele-
vated office, in framing the classifications which other observers are
to apply ; in drawing the great lines of division and subdivision which
fix the form of the subject; in setting up the type with which ex-
amples are to be compared ; in constructing the language in which
others are to narrate their facts. Steps of this kind have formed,
and must form, the great epochs in the progress of all sciences of
classification, and especially in ours ; and I need not remind you how
great the importance and the influence of such steps amongst you
have been. To pronounce at once upon the success of such steps
must always be in some degree hazardous; since their success is in
fact this, that they influence permanently and powerfully the re-
searches, descriptions, and speculations of future writers ; and there
are few of us who can pretend to the foresight which might enable
us to say, in any special case, how far this will be so. Yet the great
works of Messrs. Murchison and Sedgwick, tending to the establish-
ment of a classification of the strata below the old red sandstone
(works which, on all accounts, we must consider as a joint under-
taking), appear already to offer an augury which can hardly be
doubtful, of this influence and permanence. Mr. Murchison’s ap-
pellation of the “Silurian System” has already been adopted by
MM. Elie de Beaumont and Dufresnoy, who have given it currency
on the continent: M. Boué and M. de Verneuil announce the dif-
fusion of “ Silurian” rocks in Servia and the adjacent parts of Turkey
in Europe; our own members, Mr. Hamilton and Mr. Strickland,
have extended their range to the Thracian Bosphorus; M. Forch-
hammer, of Copenhagen, visited the “ Silurian region” to endeavour
to recognize the rocks of Scandinavia; and MM. Omalius D’Halloy
and Dumont have just explored it, to establish a parallel between
its deposits and those of Belgium. It will be observed that some of
the districts thus mentioned are out of the limits of our geological
Home circuit ; and if the identification be really and permanently
established in these cases, will extend the limits within which the pa-
rallelism of geological series can be asserted: and this is, in effect,
what we have a right to look for, sooner or later, in the progress of
geological science. As we must be careful not to apply our domes-
tie types without modification to other regions, so must we take care
not to despair of modifying our scheme, so that it shall be far more
extensively applicable than it at first appeared to be. Of this pro-
gress of things examples are too obvious and too recent to require
to be pointed out.

The labours of Professor Sedgwick refer to the “Cambrian System,”
which lies beneath the Silurian System, occupying much of North
Wales, Cumberland, and a great part of Scotland; while the Silurian
System spreads over a great part of South Wales and the adjoining
English counties. The classification of the rocks of this portion
of our island to which Professor Sedgwick has been led, though laid
before you only at a recent meeting, is the fruit of the vigorous and
obstinate struggles of many years, to mould into system a portion of
geology which appeared almost too refractory for the philosopher's

Geological Society. 451

hands; and which Professor Sedgwick grappled with the more reso»
lutely, in proportion as others shrank away from the task perplexed
and wearied. I need not attempt any detailed view of his system;
his First Class of Primary Stratified Rocks occupies the Highlands
of Scotland and the Hebrides, and appears in Anglesea and Caernar-
vonshire ; the crystalline slates of Skiddaw Forest, and the Upper
Skiddaw slate series come next. Above these is his Second Class,
or Cambrian and Silurian System. The Cambrian is divided into
Lower and Upper Cambrian, of which the former includes all the
Welsh series under the Bala limestone; the two great groups of
green roofing slate and porphyry on the north and south sides of the
mineral axis of the Cumbrian mountains (of which groups the position
had previously been misunderstood ), and parts of Cornwall and South
Devon. The Upper Cambrian System contains a large part of the
Lammermuir chain ; a part of the Cumbrian hills, commencing with
the calcareous slates of Coniston and Windermere ; the system of the
Berwyns and South Wales; all the North Devon, and a part of the
South Devon and Cornish series. Ascending thus through a series
of formations distinguished and reduced to order by the indefatigable
exertions and wide views of Professor Sedgwick, we arrive at the
Silurian system; and here we must seek our subdivisions from the
rich results of the labours of Mr. Murchison. These subdivisions
were published in the summer of 1833. Like the Cambrian, the Si-
lurian is divided into a Lower and an Upper System, the former in-
cluding the Llandeilo flags and the Caradoc sandstones ; the Upper
Silurian Rocks being the Wenlock shale and limestone, the Lower
Ludlow, the Aymestry limestone, and the Upper Ludlow, which
finally conducts us to the Tilestones or bottom beds of the Old Red
Sandstone.

That these various series of Cambrian and Silurian rocks are
really superposed on one another; that they are justly separated into
these groups ; and that the smaller groups are truly of a subordinate
nature, divided by lines less broad than those which bound the great
series of formations ;—these are points, of which the evidence must
be sought in the works to which I refer. The evidence adduced by
Prof. Sedgwick is mainly to be found in the great fact of super-
position, supported by the circumstances of dip, strike, cleavage,
mineral character, and all the great incidents of mountain masses.
To proofs of this kind Mr. Murchison is able to add the testimony
of organic fossils, of which a vast and most instructive collection is
figured in his work. These fossils of the Silurian system, amount-
ing in all to about 350 species, are essentially distinct from those
of the Carboniferous System and Old Red Sandstone. This being
80, the establishment of these great divisions is supported by that
geological evidence which properly belongs to the subject.

In detecting order and system among the monuments of the most
obscure and remote periods of the earth’s history, it may easily be
supposed that it has been necessary to employ and to improve all
the best methods of geological investigation. Prof. Sedgwick’s
classification of the oldest rocks which form the surface of this

2G2

452 Geological Society :—Anniversary of 1839.

island has of course been obtained by a careful attention to the po-
sition and superposition of the mineral masses, and by tracing the
geographical continuity of the strata, almost mile by mile, from Cape
Wrath to the Land’s End. In this manner he has connected the
rocks of Scotland with those of Cumberland ; these again with those
of Wales; and the Welsh series, though more obscurely, with that
of Devonshire and Cornwall. In this survey he has constantly kept
before his eyes a distinction, known indeed before, but never before
so carefully and systematically employed, between the slaty cleavage
of rocks and their stratification; for the directions of these two
planes, though each wonderfully persistent over large tracts, never,
except by accident, coincide. He has taken for his main guide the
direction of the strata, or, as it is called, the strike of the beds; and
in such a course, the theory of Elie de Beaumont respecting the
parallelism of contemporaneous elevations, whether true or false,
could not fail to give an additional interest to geological researches,
conducted on so large a scale as those of Prof. Sedgwick. Mr.
Murchison’s mode of investigation may be described thus: that he
has applied, for the first time, to the rocks below the Old Red Sand-
stone, the method of classification previously employed with so much
success for the Oolites. It is truly remarkable, that Nature has
placed in this our corner of the world, series, probably the most
complete which exist, of both these groups of strata; and as the
Oolites of England have long been the type of that portion of Euro-
pean geology, the Silurians of Wales may perhaps soon be recog-
nized as the standard members of a still more extensive range of
deposits. As if Nature wished to imitate our geological maps, she
has placed in the corner of Europe our island, containing an Jndea
Series of European formations in full detail.

The Carboniferous, Old Red, Silurian and Cambrian systems have,
by many writers, up to the present time, been all comprehended in
the term “transition rocks”, so far as that term has been used with
any definite application at all. The analysis of this vague group
into these distinct portions removes the confusion and perplexity
which have hitherto prevailed in this province of geology. Prof.
Sedgwick has further proposed to apply the term Palgozoic, and
Mr. Murchison that of Protozoic, to the rocks which constitute the
Cambrian and Silurian systems.

How far these appellations are useful, we shall see when we have
had speculations presented to us in which they are familiarly used ;
for necessity is the best apology, and convenience the best rule, of
innovations in scientific language. In the names applied to the
members of the Silurian system, Mr. Murchison, following those
examples of geological nomenclature which have been most clearly
understood and most generally adopted, has borrowed his terms from
localities in which standard types of each stratum occur. If the
Silurian system be as exclusively diffused as some indications seem
to imply, we may find the Ludlow Rocks in Scandinavia, and
the Caradoc Sandstone even in Patagonia. Whether a like identi-
fication of the more ancient rocks of the Cambrian series with the

Geological Society. 453

lowest formations of other countries be possible, may perhaps be
(for the present) more doubtful.

I have spoken of Mr. Murchison’s work as if it had formed part
of our Proceedings, as indeed almost every part of it has done, al-
though it now appears in a separate form. And I will add, that it
is impossible not to look with pleasure upon the form in which the
work appears, enriched as it is in the most liberal manner, with
every illustration, map and section, picturesque view and well-marked
fossil, which can aid in bringing vividly before the reader all the
instructive and interesting features of the formations there described.
The book must be looked upon as an admirable example of the
sober and useful splendour which may grace a geological mono-
graph.

Having been tempted to dwell so long on this subject from my
conviction of its importance, I must the more rapidly proceed with
the remainder of my survey. Mr. Bowman sent us, “ Notes on a
small patch of Silurian Rocks to the west of Abergele.” In this
investigation, which is interesting to us as the first application of
Mr. Murchison’s Silurian System, the author found strata of which
some could be, by means of fossils, identified with the Ludlow rocks.
Mr. Malcolmson has, by the remains of fossil fishes, shown that the
calciferous conglomerate of Elgin represents the old red sandstone
of Clashbinnie, as the Rev. G. Gordon had already supposed. _ Fi-
nally, proceeding to higher strata, we have to notice a trait of the
fossil history of the coal strata near Bolton-le-Moors, contributed
by Dr. Black. A stem of a tree thirty feet long, and inclined at
an angle of 18° in a direction opposite to the strata, was discovered,
having upon it a Sternbergia, about an inch in diameter, extending
the whole length of the stem, which had been, while living, a para-
site plant, like the mighty existing creepers of the tropical regions.

The most curious addition to our fossil characters of strata, are
the footsteps discovered on the surface of beds of the new red
sandstone. It is well known that several years ago such marks
were discovered at Corncockle Muir, in Dumfries-shire. Since that
time similar discoveries have been made at various places, and espe-
cially in 1834, in the quarries of Hesseberg near Hilbergshausen ;
and to the animal which had produced the impressions then disco-
vered, the name of Chirotherium was provisionally applied by Pro-
fessor Kaup. In the quarries of Storeton Hill, in the peninsula of
Worrall, between the Mersey and the Dee, marks were discovered
strongly resembling the footsteps of the Chirotherium of Kaup:
these were described by a committee of the Natural History Society
of Liverpool, and drawn by J. Cunningham, Esq. Mr. James
Yates has also described footsteps of four other animals from the
same quarries; and Sir Philip Egerton has given us a description
of truly gigantic footsteps of the same kind, which he terms the
Chirotherium Herculis.

Mr. Strickland gave us a notice of some remarkable dikes of cal-
careous grit which occur in the lias schist at Ethie in Ross-shire,
and which had already been remarked by Mr. Murchison, in his

4.54 Geological Society :— Anniversary of 1839.

examination of the coast of Scotland, in 1826. They appear not to
have been injected from below, but filled in from above.

Mr. Williamson’s “ View of the Distribution of Organic Remains
in part of the Oolitic Series on the Coast of Yorkshire,” was the
welcome continuation of a labour of the same kind already exe-
cuted for the lower portions of the series, and promised to be con-
tinued for the upper. Among the contributions to the fossil history
of the oolites, we must also place Dr. Buckland’s “ Discovery of the
fossil wing of an unknown Neuropterous Insect in the Stonesfield
slate.” This stratum, the Stonesfield slate, has, during the past
years, occupied the Society in the consideration of its fossils in no
small degree ; but the speculations thus suggested belong to Palz-
ontology rather than Descriptive Geology. Mr. Murchison’s notice
of a specimen of the Oar’s rock, which stands in the sea off the
coast of Sussex, nine miles south of Little Hampton, shows it to
agree with some of the rocks in the greensand or Portland beds ;
and its thus belonging to the strata below the chalk falls in with the
remark of its occurring between the parallels of disturbance which
traverse the Wealden of Sussex on the north, and the Isle of Wight
on the south; for these disturbances and other facts agree well
with the notion of protruded strata between. The Wealden strata
themselves have been observed by Mr. Malcolmson, at Linksfield,
near Elgin. It is remarkable, that these strata had already, very
unexpectedly, been found by Messrs. Murchison and Sedgwick in
the Isle of Skye.

I have also to notice Dr. Buckland’s account of the discovery of
fossil fishes in the Bagshot Sands at Goldworth Hill, near Guildford.
As these fossils resemble those of the London clay, Mr. Lyell’s
opinion that the Bagshot Sands were deposited during the eocene
period is strongly confirmed.

The freshwater beds of the Isle of Wight, which had already
supplied specimens of some of the Pachydermata of the Paris basin,
have furnished an additional supply of rich fossils, which have been
examined by Mr. Owen. He has found them to contain bones of
four species of Paleeotherium, and two species of Anoplotherium ;
also a jaw of the Cheropotamus, a fossil genus established by Cu-
vier; and another jaw closely resembling that of a Musk Deer, which
Mr. Owen refers to the genus Dicobune, a genus also established by
Cuvier upon the fossils of the Paris basin. Such discoveries, falling
in with the conclusions obtained by the researches of previous phi-
losophers respecting the tertiary period of the earth’s history, and
supplying what they left imperfect, cannot fail to give us great con-
fidence in the results of those investigations, and to enhance our ad-
miration of the sagacity which opened to us this path of discovery.

Dr. Mitchell gave an account of his attempts to trace the drift
from the chalk and strata below the chalk, as it exists in the coun-
ties of Norfolk, Suffolk, Essex, Cambridge, Huntingdon, Bedford,
Hertford, and Middlesex. This drift I had occasion to notice in my
Address last year, in reference to Mr. Clarke’s elaborate geological
survey of Suffolk; and I then stated that this diluvial deposit is

;
.
A

Geological Society. 455

known in the neighbourhood of Cambridge by the name of brown
clay. Dr. Mitchell has shown that this deposit is of greater extent
than we were before aware. But still to determine with precision
its principal masses, total extent, and local modifications, would be a
valuable service to the geology of the eastern part of our island.

As my order requires me to take the igneous after the sedimentary
rocks, I must here notice Dr. Fleming’s “Remarks on the Trap
Rocks of Fife,” which he distinguishes into three epochs ;—those of
the eastern extremity of the oolites, which are variously associated
with the old red sandstone ;—those which run from St. Andrew’s to
Stirling, which were produced after the coal-measures ;—and those
which occur along the shores of the Forth, which occur in the higher
coal-measures.

2. Foreign (South European and Trans-European) Geology.—
g yp mp dy:

In the survey of the progress of our labours which I offered to your
notice last year, I stated, that in proceeding beyond the Alps, and I
might have added the Pyrenees, we no longer find that multiplied se-
ries of strata, so remarkably continuous and similar, when their iden-
tity is properly traced, with which we have been familiar in our home
circuit. Yet the investigations of Mr. Hamilton and Mr. Strickland
appear to show, that we may recognise, even in Asia Minor, the
great formations, occupying the lowest and highest positions of the
series, which are well marked by fossils, namely the Silurian and
Tertiary formations ; and also an intermediate formation correspond-
ing in general with the Secondary rocks of the north, but not as yet
reduced to any parallelism with them in the order'of its members.
Besides these sedimentary rocks, in this as in most other countries,
there are found vast collections of igneous rocks of various kinds,
which interrupt and modify, and may mask and overwhelm, the
fossiliferous strata. A paper has been communicated to us by Mr.
Hamilton, “ On a part of Asia Minor,” namely, the country extend-
ing from the foot of Hassan Dagh to the great salt lake of Toozla,
and thence eastwards to Cesarea and Mount Argzus, and thus
occupying a part of the ancient Cappadocia.

It appears that in this district the igneous rocks occupy a large
portion of the surface, and the sedimentary strata which are asso-
ciated with these are not easily identified with those which occur
in countries already examined. The district examined by Mr. Ha-
milton contains a limestone belonging to the vast calcareous lacus-
trine formation of the central part of Asia Minor, and beneath this,
a system of highly inclined beds of red sandstone, conglomerates and
marls, which are perhaps connected with the saliferous deposits of
Pontus and Galatia; but which could not be satisfactorily com-
pared with the beds of the south of Europe, for want of the occur-
rence of organic remains. In only one instance did Mr. Hamilton
observe the trace of organic bodies in the sandstone: these were
impressions resembling fucoids, and similar to those found in the
Alpine limestone near Trieste. Mr. Hamilton ascended to the
summit of Mount Argeus, which had not previously been reached

456 Geological Society :—Anniversary of 1839.

by any traveller, which rises abruptly from the alluvial plain of
Cesarea to the height of 13,000 feet.

We have another contribution to the geology of the countries
exterior to the Alps and Pyrenees in Mr. Sharpe’s memoir on the
geology of Portugal. He has examined with great care the neigh-
bourhood of Lisbon, and has traced the superposition of the strata,
naming the most conspicuous of them from the places in which
they are well exhibited. His series (exclusive of igneous rocks)
consists of San Pedro limestone (which rests upon the granite),
slate clay and shale, Espichel limestone, red sandstone, hippurite
limestone, a lower tertiary conglomerate, the Almada beds, and the
upper tertiary sand. In the Memoirs of the Royal Academy of
Sciences of Lisbon, for 1841, Baron Eschwege had examined a
geological section taken across the mouth of the Tagus, and passing
from the granite of the Serra of Cintra, to that of the Serra of Arra--
bida. But his identifications of the Portuguese beds do not agree
with those of Mr. Sharpe, and have indeed the air of proceeding on
the arbitrary assumption of a correspondence between this and
other parts of Europe. Thus Baron Eschwege has referred both
the San Pedro and the Espichel limestones to the magnesian
limestone; the red sandstone formation he considers as Bunter
Sandstein, while Mr. Sharpe refers it to the age of our Oolites : the
hippurite limestone (now acknowledged to be the equivalent of our
chalk and greensand) M. Eschwege makes tu be Jura limestone ; and
the Almada beds he would have to be Plastic Clay and Calcaire
Grossier. Mr. Sharpe is very properly attempting, by a further
study of the organic fossils which he has procured, to confirm or
correct the identifications to which he has been led. It is only by
thus starting from different points, and tracing strata by their conti-
nuity, that we can hope to cover the map of Europe, and finally
the world, with geological symbols of a meaning fully understood.

PALZONTOLOGY.

The portion of our subject which we term Paleontology, might
at first sight seem to form a part of zoology rather than of geology ;
since it is concerned about the forms and anatomy of animals, and
differs from the usual studies of the zoologist only in seeking its
materials in the strata of the earth’s crust instead of upon its sur-
face. Yet a moment's thought shows us how essential a part of
our science the zoology of extinct animals is; for in order to learn
the history of the revolutions which the earth has undergone, we
must seek for general laws of succession in the remains of organic
life which it presents, as well as in the position and structure
of its brute masses. And since such general laws must necessarily
be expressed in terms of zoology, it becomes our business to define
those terms, so that they shall be capable of expressing truths which
include in their circuit the past as well as the present animal and
vegetable population of the world.

An example of this process has occupied a large portion of our
attention during the past year. It appeared to be a proposition

Geological Society. 457

universally true, that the oldest strata of the earth’s surface con-
tained cold-blooded animals only ; and that creatures of the class
mammalia only began to exist on the surface after the chalk strata
had been deposited and elevated. And when, to a rule of this
tempting generality, a seeming exception was brought under our
notice, it became proper to examine, whether the anatomical line,
which enables us to separate hot-blooded from cold-blooded ani-
mals, had really been rightly drawn ; and whether, by rectifying
the supposed characteristic distinction, the exception might not
be eliminated. The exception on which this very instructive point
was tried, consisted in a few jaw-bones of a fossil animal, which,
though occurring in the Stonesfield slate near Oxford, a bed belong-
ing to the oolite formation, had been referred by Cuvier to the
genus Didelphys, and thus placed among marsupial mammals.
In August last M. de Blainville stated to the Academy of Sciences
of Paris his reasons for doubting the justice of the place thus as-
signed to the fossil animal. Founding his views principally upon
the number and nature of the teeth of the fossil, he asserted that
the animal, if a mammal, must come nearest the phoce ; but he ra-
ther inclined to believe it a saurian reptile ; following, as he con-
ceived, the analogies offered by a supposed fossil saurian described
by Dr. Harlan of Philadelphia, and termed by him Basilosaurus.
M. Valenciennes, on the other hand, asserted the propriety of the
place assigned by Cuvier to the fossil animal, although he made it a
new genus; and gave to the species the name Zhylacotherium Pre-
vostii. The controversy at Paris had its interest augmented when
Dr. Buckland in September carried thither the specimens in ques-
tion. From Paris the controversy was transferred hither in No-
vember, and principally occupied our attention at our meetings till
the middle of January.

One advantage resulting from the ample discussion to which the
question has thus been subjected, has been, that even those of us
who were previously ignorant of the marks by which zoologists
recognise such distinctions as were in this case in question, have
been put fully in possession of the rules and the leading examples
which apply to such cases. And hence it will not I trust be deemed
presumptuous, if, without pretending to any power of deciding a
question of zoology, I venture to state the result of these discus-
sions. It appears, then, that some of the marks by which the under
jaws of Mammals are distinguished from those of Saurians are the
following : (1) a convex condyle ; (2) a broad and generally elevated
coronoid process, (3) rising near the condyle; (4) the jaw in one
piece ; (5) the teeth multicuspid, and (6) of varied forms, (7) with
double fangs, (8) inserted in distinct sockets, but (9) loose and not
anchylosed with the jaw. In all these respects the Saurians differ ; ha-
ving, for instance, instead of a simple jaw, one composed of six bones
with peculiar forms and relations, and marked by Cuvier with di-
stinct names ; having the teeth with an expanded and simple fang, or
anchylosed in a groove, and so on. Of course, it will be supposed,
by any one acquainted with the usual character of natural groups,

458 Geological Society :—Anniversary of 1839.

that this line of distinction will not be quite sharp and unbroken,
but that there will be apparent transgressions of the rule, while yet
the unity of the group is indubitable. Thus the Indian Monitor
and the Iguana, though Saurians, violate the second character,
having an elevated coronoid process ; but then it is narrow, and this
seeming defect in our second character is further remedied by
the third ; for in those Saurians there is a depressed space between
the condyle and the coronoid process quite different from that which
a mammal jaw exhibits. Again, the teeth of Crocodiles, Plesio-
saurs, and the like, are inserted in distinct sockets; but then they
have not double fangs. The Basilosaurus was supposed to be a sau-
rian with double-fanged teeth, but that exception was disposed of
afterwards. And as there are thus saurians which trench upon the
characters of mammals, there are mammals in which some of the
above characters are wanting: thus the condyle is slightly or not
at all convex in the Ruminantia; there is no elevated coronoid pro-
cess in the Edentata; the Dolphin and Porpoise have not multi-
cuspid teeth; the Armadillo has not varied forms of teeth, nor has
it double fangs to its teeth, which also the fossil Megatherium has
not. Still, wpon the whole, the above appears to be the general
line of distinction. Even if one or two of the above nine marks
were wanting to prove the animal a mammal, still if the great ma-
jority of them were present, our judgment could not but be decided
by the preponderance of characters. But if all the above characters
of mammals are present, and all those of saurians absent, it seems
to be a wanton scepticism to doubt that the animal was really warm-
blooded.

Now it was asserted by Mr Owen, who brought this subject be-
fore us, that this is the case; that all the characters which I have
enumerated above exist in the Stonesfield jaws. If we satisfy our-
selves that this is the case, I do not see how we can avoid assenting
to his opinion,—that the animal belonged to the class Mammalia.

Every such question of classification must resolve itself into two;
that of the value, and that of the existence of the characters. If we
assent to Mr. Owen in his view of the former, we are then led to
consider the latter.

M. de Blainville, at least in his first examination, had laboured
under the disadvantage of forming his judgments from casts and
drawings only of the Stonesfield bones. Under these circumstances,
he had denied several of the above characters; he had held that the
teeth in the Thylacotherium are uniform; and that they are con-
fluent with the jaw; and that the jaw is compound. ‘These state-
ments Mr. Owen, resting upon a careful examination of the speci-
mens, contradicts. The assertion of the compound nature of the
jaw is occasioned by a groove near the lower margin of the jaw,
which however is not so situated as to represent the saurian sutures,
but is completely explained by supposing it to be a vascular canal,
such as exists in the Wombat, Didelphys, Opossum, and similar ani-
mals.

Another specimen, at that time the property of Mr. Broderip,

Geological Society. 459

but now very properly placed in the British Museum, exhibits a
jaw similar indeed to the Thylacothere, but belonging to a different
genus ; and to this species Mr. Owen has given the name Phasco-
lotherium Bucklandi. Both these generic names imply that the
animals are pouched animals ; and in addition to the reasons which
led Cuvier to this opinion, Mr. Owen has noticed in the fossils an in-
flection of the lower edge of the jaw, which, so far as has been
hitherto observed, occurs in Marsupials, and in them alone.

As if this question had been destined to be settled at this time,
the only remaining doubt with regard to the possible existence of
double fangs in the teeth of a saurian was removed by the arrival
in London of Dr. Harlan with his “ Basilosaurus.” That gentleman,
with great liberality and candour, allowed sections of the fossil to
be made in such a manner as to expose the structure of the teeth.
And these being examined by Mr. Owen, and compared with the
general laws of dental structure which he has lately discovered, it
appeared that Dr. Harlan’s fossil was by no means a saurian, but
an animal nearly allied to the Dugong, to which Mr. Owen pro-
poses to apply the generic name of Zeuglodon, expressing the con-
joined form of its teeth.

I have not hesitated to lay before you the view of this subject to
which I have been led by the discussions in which we have been
engaged, notwithstanding the very great authorities which incline
to the other side of the balance. Among these I hardly know
whether I am to reckon Mr. Ogilby, who laid before us a very in-
structive communication, in which, without deciding the point, he
pointed out the difficulties which appear to him to embarrass both
views, and especially to contradict the opinion of the marsupial
nature of the animal.

I have dwelt the longer on this controversy, since it involves con-
siderations of the most comprehensive interest to geologists, and,
we may add, of the most vital importance. For—de summd reipub-
lice agitur,—the battle was concerning the foundations of our phi-
losophical constitution; concerning the validity of the great Cuvierian
maxim,—that from the fragment of a bone we can reconstruct the
skeleton of the animal. This doctrine of final causes in animal
structures, as it is the guiding principle of the zoologist’s reasonings,
is the basis of the geologist’s views of the organic history of the
world ; and, that destroyed, one half of his edifice crumbles into
dust. If we cannot reason from the analogies of the existing, to the
events of the past world, we have no foundation for our science ; and
you, Gentlemen, have all along been applying your vigorous talents,
your persevering toil, your ardent aspirations, idly and in vain.

Besides the important investigations thus referred to, we owe to
Mr. Owen other paleontological contributions. The genus Chero-
potamus, established by Cuvier from an imperfect fragment of the
bone of a skull, was asserted by him to be a Pachyderm most nearly
allied to the Peccari. A fragment of a lower jaw of the same genus,
found by Mr. Darwin Fox in the Isle of Wight, confirms this view,
but indicates in some points an approach to the carnivorous type.

460 Geological Socicty :—Anniversary of 1839.

And it was remarked as interesting, that the living genus of the hog
tribe which most resembles the Cheropotamus, the Peccari, exists
in South America, where the Tapir, the nearest living analogue of
the Anoplothere and Palzothere, the associates of the Cheeropo-
tamus, also occur. Another jaw, fornd by Mr. Pratt in the Binstead
quarries in 1830, and resembling that of the Musk Deer, Mr. Owen
refers to a new species of Cuvier’s genus Dicobune, under the name
Dichobune cervinum. Mr. Owen has also given us a description of
Lord Cole’s specimen of Plestosaurus macrecephalus, which he com-
pares with Mr. Conybeare’s Plesiosaurus Dolichodeirus, by establish-
ing an intermediate species, founded upon a specimen existing in
the British Museum, and termed by him Plesiosaurus Hawkinsit.
Besides tracing the analogies which connect these with each other,
and comparing them with the two great modifications of the saurian
tribe, the crocodiles and the lizards, Mr. Owen presented his remarks
on the form of the Plesiosaurian vertebra, founding them upon a
general view of the elements of which all vertebra are constituted.

To the communications thus made to us, we may add Mr. Owen’s
determination of another animal, of which the remains brought from
the neighbourhood of Buenos Ayres, are among the many treasures
of this kind which we owe to Sir Woodbine Parish. This animal,
of gigantic dimensions, appears to have been allied to the Megathe-
rium, but with closer affinities to the Armadillos; and it probably
possessed the characteristic armour, of which, in the Megatherium,
the existence is perhaps problematical. Mr. Owen has termed it
Glyptodon, trom the furrowed shape of its teeth. ;

In another communication Mr. Owen endeavoured to account for
the dislocation of the tail of the Ichthyosaurus at a certain point,
which is observable in many of the fossil skeletons of that animal.
This circumstance, so remarkable from its general occurrence, and
which Mr. Owen was the first to observe, he is disposed to account
for by supposing a broad tegumentary fin to have been attached to
the tail for a portion of its length, the position of which fin must,
he conceives, have been vertical.

I cannot close my enumeration of the valuable contributions for
which we are indebted to Mr. Owen, without remarking how well
our anticipations have been verified, when, in awarding him the
Wollaston medal last year, we considered the labours which we thus
distinguished as only the beginning of an enlarged series of scientific
successes; and how well also Mr. Owen’s own declaration, that he
should lose no available time or opportunity which could be applied
to paleontological research, has been borne out by the services he
has rendered that branch of our science.

In the remainder of my review of what has been done among us
in Paleontology I must necessarily be very brief. I have already
mentioned the discovery of fossil fishes in the Bagshot sand. These
fishes have supplied three new genera, which Dr. Buckland has
distinguished and has named Edaphodon, Passalodon, and Ameibo-
don; of which the two first offer combinations of the characters of
bony and cartilaginous fishes. Mr. Stokes has given us his views of

’
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.
:

Linnean Society. 461

the structure of the animal to which belonged those fossils with
which we are so familiar under the name of Orthoceratites. He is of
opinion, that these fossils, in their living condition, existed as a shell,
enveloped within the body of the animal to which they belonged.
He has distinguished three genera of these shells, to which he as-
signs the names Actinoceras, Ormoceras, and Huronia. The Mar-
quis of Northampton also has examined those minute spiral shells
which occur in the chalk and chalk flints, and have been termed
Spirolinites. And, finally, under this head I must mention Mr.
Alfred Smee’s paper on the state in which animal matter is usually
found in fossils.

Mr. Austen’s hypothesis of the origin of the limestone of Devon,
though belonging in some measure to Geological Dynamics, may
perhaps be mentioned here, since he explains the position of those
beds by reference to the habits of the coral animal. Mr. Austen
has already shown himself to us as an excellent observer ; and in con-
structing geological maps, a task requiring no ordinary talents and
temper, he has earned our admiration. We shall therefore not be
thought, I trust, to depreciate his labours if we receive with less
confidence speculations in their nature more doubtful. As we can
hardly suppose the calcareous beds of Devon to have had an origin
different from those of other countries, we cannot help receiving
with some suspicion a doctrine which would subvert almost the
whole of our existing knowledge of the relations of fossiliferous beds
of limestone. ——_—

LINNZAN SOCIETY.

Dec. 4, 1838.— Read, ‘‘ Observations on the Anatomical and
Physiological Nature of Ergot in certain Grasses.” By E. J.Queckett,
Esq., F.L.S.

From the observations detailed in this paper, which have been fol-
lowed up in many ergotized grasses, Mr. Queckett is inclined to be-
lieve that the ergot is a grain diseased by a particular parasitic fungus
developing in or about it, whose sporidia find the young state of the
grain a matrix suitable for their growth, and quickly run their race,
not entirely depriving it of its vitality, but communicating to it such
impressions, which pervert its regular growth, and likewise the
healthy formation of its constituents, being at last composed of its
diseased materials, which are mixed up with fungic matter, which
has developed within it.

Dec. 18.—Read, “A notice of Cereus tetragonus,” by Edward
Rudge, Esq., F.R. & LS.

Read, ‘“ Descriptions of the Indian species of Iris,” by D. Don,
Esq., Libr. L.S., Prof. Bot. King’s College.

Read, “« Additional observations on the Spongilla fluviatilis.” By
John Hogg, Esq., M.A., F.L.S.

Jan. 15, 1889.—Read, ‘‘ A notice of the Encephalartos horridus,
which flowered at Kinmel Park.” By Mr. Thomas Forrest. Com-
municated by the Secretary ; also “‘ An account of the Indian species
of Juncus and Luzula.” By D. Don, Esq., Libr. L.S., Prof. Bot.
King’s College.

462 Linnean Society.

Feb. 5.—Read, a paper entitled “A Note upon the Anatomy of
the Roots of Ophrydee.” By John Lindley, Ph. D., F.R. and L.S.,
Prof. Bot. University College.

The object of the author in this paper was to show that salep, the
prepared roots of certain Ophrydee@, is not a substance consisting
principally of starch, as is the common opinion among writers of the
present day, but is composed of a bassorine-like matter, organized
in a peculiar manner.

After stating the opinions of recent authorities, the author gives
the results of his own microscopical examination of the tissue of re-
cent and prepared roots, by which it appears that the tubercles of
Ophrydee universally contain large cartilaginous nodules of a muci-
laginous substance, not coloured by iodine, and a small quantity of
the grains of starch, lying in the usual manner in the parenchyma
which surround the nodules, and readily susceptible to the usual ac-
tion of iodine. The tubercles of many South-African Ophrydee pre-
sent when dried the appearance of bags filled with small pebbles, as
if the epidermis had contracted over hard bodies in the inside. Ifa
fresh root of Satyrium pallidum be divided transversely the cause of
this appearance is explained, for with its soft parenchyma are mixed
tough nodules, clear as water, and often twenty times as large as the
cells which surround them. These nodules are easily separable, are
tough like horn, and on being sliced appear to be perfectly homo-
geneous. They are scarcely soluble in cold water ; when boiled they
become tumid and partially dissolve intoa transparent jelly. If ex-
posed to the air they rapidly dry and become brown. The aqueous
solution of iodine has no sensible effect upon them in their natural
state.

On charring slices of some salep procured at Covent Garden, a
coarse preparation of wild Opirydee, the author found that the no-
dules apparently homogeneous were composed of extremely minute
transparent cells, filled, as he supposed, with a secretion of the same
refractive power as themselves, and adhering naturally to each other
firmly ; the double walls of the cells and intercellular spaces being
only made apparent by the charring process, The author explains
the error of those who have considered salep to consist chiefly of
starch, by allusion to the mode of its preparation. The tubercles
are first parboiled and then dried, the effect of which is to dissolve
what starch exists in the cells surrounding the nodules. The dis-
solved starch flows over the surface of the nodules, from which when
dried it is undistinguishable, and consequently when iodine is ap-
plied to salep the mass appears to become iodide of starch. If the
nodules, however, after this action of iodine, be removed, they are
seen to retain their original vitreous lustre.

The author remarks that these nodules of Opirydee are, as far as
his observations extend, absent in the tubercles of the other tribes
of Orchidacee.

Read, a paper entitled ‘Some Data towards a Botanical Geogra-
phy of New Holland.” By Dr. John Lhotsky, late of the Civil Ser-
vice, Van Diemen’s Land, Communicated by Prof. Don, Libr, L.S,

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Edinburgh Society of Arts. 463

Feb. 19.—Read, ‘‘ Extracts from Letters addressed to Dr. Royle,
V.P.R. & F.L.S., Prof. Mat. Med., King’s College. By Dr. Fal-
coner, Superintendent of the Hon. E. I. C.’s Garden, Saharunpore.”

EDINBURGH SOCIETY OF ARTS.

April 17.—Among the communications laid before the Society
at this meeting was the following :

Notice of recent improvements effected by him in Photographic
Drawing, &c. whereby the lights and shadows are not reversed. By
Andrew Fyfe, M.D., F.R.S.E., Vice-Pres. Soc. Arts.*

Before proceeding to describe his method of taking impressions
without having a reverse, Dr. Fyfe stated that he had received com-
munications from several gentlemen, mentioning that they had re-
peated his experiments with the phosphate of silver paper, and also
with the ammonia, as a preservative. With regard to the latter, it
was found by them all to prevent the further action of the light on
the specimens, provided it was properly applied. Asa test of its pro-
per application, he stated, that the best method is to put the paper
into a diluted solution of the ammonia, and to leave it for a short
time, till all the yellow parts of the impression become white, show-
ing that the whole of the yellow phosphate is washed out. An im-
pression on paper, taken by Mr. William Forrester, lithographer,
was shown. In this the lights and shadows were preserved as in
the original, by covering the light parts of the drawing from which it
was taken with a dark ground, and leaving the darker parts lighter
and lighter, so as to allow the greater transmission of light through
what in the original was the darkest. A lithographic stone was
likewise shown, on which an impression was taken by Mr. Nichol,
lithographer, by covering the stone with phosphate of silver, and
then, after putting an engraving on it, expesing it to light in the
usual way. Dr. Fyfe then proceeded to describe the process by
which he had succeeded in. getting impressions, in which the lights
and shadows are not reversed, For this purpose the phosphate pa-
per is first darkened by the action of light ; it is then immersed in a
solution of the iodide of potassium, and while still moist, exposed to
light, with the object, the impression of which is to be taken, placed
on it, and left till the whole of the paper exposed becomes yellow,
and when removed it exhibits a distinct representation of the object.
In this process there is a tendency of the iodide to convert the dark
phosphate into yellow iodide of silver, which it does instantly when
the solution is strong, but very slowly when it is weak, unless it is
exposed to light, and then the action goes on rapidly. It was obser-
ving this that induced Dr. Fyfe to try the influence of light on phos-
phate paper besmeared with iodide of potassium, by which he was led
to the discovery. Of course, when an object, which allows the light
to pass through it differently, is put on the paper, those parts on

* For other papers on this subject see our numbers for March and May,
p. 196, 365, and 368 : also Miscellaneous Articles in the present number,—
Epir.

464 Notices respecting New Books.

which the denser portions of the object are placed still retain their
dark colour, the other parts are tinged, just according to the trans-
mission of the light. When impressions thus prepared are kept, they
gradually begin to fade, owing to the continued action of the iodide
of potassium, and hence the necessity of submitting them to a preser-
vative process. After numerous trials, that which seemed to answer
best, was merely immersing them in water for a few minutes, and
in some cases even allowing a stream of water to flow gently on
them, so as to wash out the whole of the iodide of potassium not acted
on—in this way the agent which tends to decolorate the blackened
phosphate, seems to be removed. Several specimens of impressions
from dried leaves were shown, in which the different parts seemed
to be as nicely delineated, asin the other process, where the reverse
is given. Dr. Fyfe, however, stated, that though they seemed to
be preserved, yet he could not positively assert that they were so,
as they had been prepared only a few days. He also mentioned, that
owing to the unfavourable state of the weather, he had tried the
Camera Obscura only once, and though there was no sunshine, he
had succeeded in getting a very faint delineation, from which he was
in hopes that, in this way, a true representation may be obtained.
He also stated, that impressions may be got by using darkened
chloride paper in the same way. In this case the solution of iodide
must be much weaker than that for the phosphate, the chloride
being more easily acted on. In both cases the solution is made of
such strength, that when the paper is touched with it, it acts on the
phosphate or chloride feebly, and then, before being spread on, it
must be diluted with a little water, so as just to have it of such
strength that it does not act. A specimen of impression from chloride
was also shown.

LXIX. Notices respecting New Books.

An Elementary Treatise on the Tides. By J. W. Luszock, Esgq.,
Treas. R.S., F.R.A.S., and F.L.S., Vice-Chancellor of the Uni-
versity of London. Lond. 1839, pp. 54; with two plates of tables
and a map.-

E find in the Preface to this work a notice of the origination,
in the hands of Mr. Lubbock, of the attention which the neg-
lected subject of the tides has of late years received from British men
of science, and of which our reports of the proceedings, both of the

Royal Society and of the British Association, nearly throughout the

present series of the Philosophical Magazine, have presented the main

results, chiefly as given in the researches of Mr. Lubbock and Prof.

Whewell. Mr. Lubbock’s first examination of the London Dock ob-

servations was undertaken in 1829, at the instance of the Committee

of the Society for the Diffusion of Useful Knowledge, with the view
of obtaining correct tables for predicting the time and height of high-
water for the British Almanac. When, however, the quantity which
is called the semi-menstrual inequality had been determined with suf-
ficient accuracy for practical purposes, the further researches in the
difficult problem, the solution of which had thus been essayed, could

Mr. Lubbock’s Elementary Treatise on the Tides. 465

not have been so soon undertaken, but for the interest felt in the
subject by some individuals distinguished in science, particularly by
Mr. Whewell, and but for the pecuniary grants which were in con-
sequence devoted to it by the British Association.

Mr. Lubbock having been thus enabled to procure the valuable
assistance of Mr. E. Russell and Mr. Jones, the results have been
published by him in the Philosophical Transactions, as above inti-
mated; ‘‘ but as he is not aware,” he remarks, “ that any detached
elementary Treatise on the Tides exists in the English or in any other
language,” he trusts that a more connected view of the subject may
not be uninteresting. In the interest of the connected view of the
subject which Mr. Lubbock has taken, accordingly, in the work now
before us, every one must concur who is enabled to appreciate its
importance.

The treatise commences with an historical notice of the inquiry
into the theory and laws of tidal phenomena, tracing it from Pliny
to Kepler and Wallis; stating in succession the true theory as dis-
covered by Newton, and the researches of Bernoulli and Laplace, and
concluding with the remark, ‘The attention of Laplace does not
appear to have been directed to the construction of Tide Tables for
predicting the time and height of high-water at any port ; until very
recently, this practical solution of the problem was attempted only
in Great Britain.”

We next have the ‘‘ Mathematical Theory of the Oscillations of
the Surface of the Ocean ;”” which is succeeded by the ‘“‘Comparison
of Theory with Observation,” the ‘‘ Method of predicting the Time
and Height of High-water,” and copious and explicit directions for
making and recording “‘ Observations of the Tides.”

We extract the following remarks on the relations of the subject
of the tides to various other branches of science which occur inci-
dentally, but which we conceive are of great interest.

“The branch of the subject which appears at present to stand in
need of the most laborious exertions, is the accurate determination
of the semi-menstrual inequality and the local constants (from which
the quantities (4), D, (4) may be immediately obtained) for other
places than Liverpool and London. Until this is done, our know-
ledge of the progress of the tide-wave and of the circumstances
which attend it must be very defective. This question is not unin-
teresting to geologists, for, until it has been taken up carefully and
extensively, it will be impossible to detect slight changes in the re-
lative level of sea and land, except in narrow seas, such as the Bal-
tic, which are exempt from tides. Even to trace the gradual extinc-
tion of the semi-menstrual inequality between London and Tedding-
ton, or inany similar locality, would not be unprofitable.’’—Pref. p. v.

“The great real obstacle to perfection in calculations or predic-
tions of the tides consists in the fluctuations of the establishment.
Suppose the establishment (or the constant to be added to ) changes
a minute per annum, and that having determined it from ail the ob-
servations of twenty-one years, we proceed to employ it in calcula-
tions of the time of high water. It is obvious that if we calculate

Phil, Mag, S$. 3, Vol, 14, No, 91. June, 1829, 2H

466 Notices respecting New Books.

for the eleventh year, and compare the calculated times of high water
with the observed times, they will not be affected with any constant
error, but if we calculate for the twenty-first year the calculated times
will have a constant error of 10 minutes. Similar remarks apply to
the heights, that is, to the constant D. If the channel becomes
deeper, the tide-wave travels with greater velocity, and the high
water happens sooner. Thus again an indication arises which may
hereafter be useful to the geologist.”—Ib. p. vi.

** The practice which at present obtains of referring the heights
of buildings and mountains to the level of the sea or to high or low
water mark, seems objectionable. The heights of spring or neap
tides, although not subject to so much uncertainty, are also quanti-
ties too vague to be used with propriety as standards of reference.”
—p. 24.

“The establishment of London (2. e. the interval between moon’s
transit F at 0°0™ and the time of high water) appears now to be very
different from what it was in the time of Flamsteed. It seems to
have fluctuated more than ten minutes even since the commence.
ment of this century. At the London Docks, in 1807, it was 250:9™;
in 1818, 1°57:0™; in 1835, 2" 4-4™.—See Phil. Trans. 1837, p.136,
and the accompanying plate. These numbers were obtained by Mr.
E. Russell, and the corrections requisite in order that they might
refer to the same parallax and declinations were carefully applied.

«This perplexing fluctuation presents an insuperable obstacle to
extreme accuracy in tide predictions, until it can be explained. It
is probably owing to changes in the bed of the river, the drainage of
the banks, &c., which it is impossible to embrace in any mathema-
tical formula. Perhaps the manner of taking the observations may
have varied slightly.

«J am indebted to Mr. Yates for notice of a very ancient tide
table which exists in a MS. in the British Museum. It is in the
Codex Cottonianus, Julius DVII., which appears to have been writ-
ten in the 13th century, and to have belonged to St. Alban’s Abbey,
It contains calendar and other astronomical or geographical matters,
some of which are the productions of John Wallingford, who died
Abbot of St. Albans, a.p. 1218. At p. 45 b. is a table on one leaf,
showing the time of high water at London Bridge, ‘ flod at london
brigge’, thus :

/Btas
Lune.
h m
1 3 48
2 + 3
3 5 24 N.B. The numbers increase by
4 6 12 a constant difference of forty-eight
eee minutes. ‘The first column gives
wp td pf meres | ieeas the moon’s age in days.
28 1 24
29 2 12

ee ee

Prof. Wallace’s Geometrical Theorems. 467

Hence it would appear that high water at London on full and change
was at that epoch 3" 48™, or more than an hour later than at pre-
sent. The time of high water at London on full and change is given
in Mr. Riddle’s Navigation and in other works 2" 45™; Flamsteed
made it 35.”—pp. 32, 33.

‘Tt has been remarked, that in consequence of the sheltered si-
tuation of the port of London, the great undulations produced by
the winds will be less sensible there than on the coasts of France,
as at Brest for example. But it should be recollected, that if the
tide at London is to be considered as a derived tide, transmitted from
the Atlantic, the irregularities which are felt at Brest will equally
tend to affect it at all those places which it reaches subsequently.

*«« During strong north-westerly gales, the tide marks high water
earlier in the river Thames than otherwise, and does not give so
much water, whilst the ebb-tide runs out later, and marks lower;
but, upon the gales abating and the weather moderating, the tides
put in and rise much higher, whilst they also run longer before high
water is marked, and with more velocity of current, nor do they run
out so long or so low.’ For this information with respect to the in-
fluence of the wind on the tides in the river Thames, I am indebted
to Sir J. Hall.

«Tt has been found, that since the construction of the new Lon-«
don Bridge and the removal of the old foundations, there is less
water at the St. Katherine Docks at low water by about 18 inches
than formerly, but as respects the depth of high water it is the same ;
in other words, the flood-tide at the entrance of the St. Katherine
Docks lifts about 18 inches more within the time of flood than for-
merly. I am indebted to Sir J. Hall for this information. I do not
however attribute the fluctuations of the establishment to the removal
of the old bridge. They began long before the foundations were
touched.’”’—pp. 48, 49.

We hope that the students of exact science may receive many
more elementary treatises from the pen of the same distinguished
author.

Geometrical Theorems and Analytical Formule, with their application
to the solution of certain geodetical problems, with an Appendix con-
taining a description of two copying instruments. By Wi.utiam
Watiace, LL.D., Emeritus Professor of Mathematics in the
University of Edinburgh ; Fellow of the Royal Society of Edin-
burgh; Fellow of the Royal Astronomical Society ; Member of
the Cambridge Philosophical Society ; Honorary Member of the
Society of Civil Engineers, &c. 155 pp. 8vo.

Tue above work is the production of a man who has been well
known to the scientific world for nearly fifty years, and who, in
the course of that period, has distinguished himself by excellent
treatises on various branches of mathematics in the Encyclopedias,
and by original mathematical papers of great merit in the transac-
tions of learned societies, It has been written in interesting circum-
stances. Several years ago he Pliage from the active duties of
2H2

468 Notices respecting New Books :—Prof. Faraday’s

his chair, in consequence of infirm health, and the present work is
the fruit of his leisure, indicating however that, while the powers of
his body have been enfeebled, the powers of his mind remain unim-
paired. It contains many new, curious, and elegant properties of
triangles, quadrilaterals, and conic sections. It abounds also with
practical applications, particularly to surveying on an extensive
scale. One of the most useful problems in surveying is, given three
points in a country, and the angles which the distances between them
subtend at a fourth, to find the distances of these three from the fourth.
It is a problem as old as the days of Hipparchus, was applied by
Suellius in measuring a degree of the meridian, and has engaged the
attention of distinguished analysts in more recent times. This
problem Mr. Wallace has solved in a manner extremely convenient
for the application of logarithms. Another problem to which Mr.
Wallace has paid great attention in this work, may be enunciated as
follows: four points in a country being supposed to be joined by straight
lines, given the angles of two of the triangles having one of the six
straight lines for a common base, and given also one of the six lines,
to find all the other lines and angles in the figure.

He has shown the success of his formule by application to ex-
amples taken from the great trigonometrical surveys of Britain and
France.

The value of Mr. Wallace’s work to surveyors is greatly increased
by a particular description of an instrument which he invented some
years ago, and which he calls an Hidograph. The object of it is to
reduce or enlarge plans in a given ratio. This it accomplishes in a
manner far superior to the pantograph, the only instrument pre-
viously known for that purpose. Mr. Wallace described the eido-
graph in the 13th vol. of the Transactions of the Royal Society of
Edinburgh. But it may be hoped that the present work will make
this valuable contribution to the arts more extensively known. He
has also given a description of some other instruments which he has
invented for the solution, by geometrical construction, of the first of
the two problems mentioned above.

Mr. Wallace’s work assumes particular importance at the present
moment, when the trigonometrical survey of Britain, which had
been suspended for several years, is about to be resumed. We hope
that the author’s health will continue such for many years as to
enable him to enlighten the public by his ingenious labours.

The Eidograph is made by Mr. Adie, optician, Edinburgh. Price
nine guineas.

Experimental Researches in Electricity. By Micuart Farapay,
D.C.L., F.R.S., Fullerian Professor of Chemistry in the Royal
Institution, &c. Reprinted from the Philosophical Transactions

of 1831-1838. Lond. 1839. 8vo. Pp. 574, with Eight Quarto
Plates.

Ir is unnecessary, in addressing the readers of the Philosophical
Magazine, either in that particular character, or as members of the

Experimental Researches in Electricity. 469°

republic of science in general, to expatiate on the subject of Pro-
fessor Faraday’s discoveries and researches in electrical science. In
the former character, our readers have become acquainted with his
contributions to the knowledge of one of the most active and per-
vading, and at the same time most recondite of the principles which
govern the material world, by the abstracts which have from time
to time appeared in our pages, of his Experimental Researches in
Electricity, as they have been communicated in successive series, to
the Royal Society, and from our having reprinted several of those
series entire; while as forming part of the scientific world at large,
they must necessarily participate in the wide diffusion of his most
laboriously earned reputation. We do not intend, on the present
occasion, to offer any opinion of our own, on the value and character
of Mr. Faraday’s labours in electricity and the cognate sciences, but
we will at once refer the matter to an arbiter, from whose award, in
such a case, few will be disposed to appeal,—and stamp a character
on the present article, by giving additional currency to the judg-
ment pronounced by the Rey. Professor Whewell, who, in his
“‘ History of the Inductive Sciences,” has affirmed, with respect to
the great principle of the identity of electrical and chemical action,
that ‘The confirmation of Davy’s discoveries by Faraday is of the
nature of Newton’s confirmation of thé views of Borelli and Hooke
respecting gravity, or,” [and this, we may remark, is scarcely infe-
rior praise] “ like Young’s confirmation of the undulatory theory of
Huyghens.”

We have selected an opinion pronounced on the chemical bearings
of Mr. Faraday’s labours, because we think, that in consequence of
the ease with which brilliant and even marvellous experimental re-
sults in the magnetic relations of electricity may now be obtained,
his contributions to the science of Electro-chemistry, are perhaps, by
many of the lovers of electricity as well as chemistry, at the present
time not sufficiently attended to. It would have been easy, how-
ever, to have cited opinions not less emphatic, on Mr. Faraday’s
discoveries in magneto-electricity, the other great branch of the
general science to which his results, in the first eight series at least,
chiefly refer. Were we to offer an opinion of our own on the con-
tents of the subsequent series, we should allude to the importance
of the subject of Induced Electricity, as it has been treated by our
author; in reference, especially, to the philosophy, in all cases,
(whether electrical or not) of what has been called distant action.
On this particular subject, one of almost universal extent, science,
we are convinced, is yet pregnant with discovery.

The volume now before us consists of Mr. Faraday’s Fourteen
Series of Experimental Researches in Electricity, which have ap-
peared in the Philosophical Transactions during the Jast seven years ;
his chief reason for their publication in this form, being stated, in
the Preface, to have been “‘ the desire to supply at a moderate price
the whole of these papers, with an index, to those who may desire
to have them.” ‘There are some other passages in the preface which

470 Notices respecting New Books.

we think it desirable to cite, both in justice to the author, and on
account of their intrinsic interest ;—

“The readers of the volume will, I hope, do me the justice to remember
that it was not written as a whole, but in parts; the earlier portions rarely
having any known relation at the time to those which might follow. If I
had rewritten the work, I perhaps might have considerably varied the form,
but should not have altered much of the real matter: it would not, however,
then have been considered a faithful reprint or statement of the course and
results of the whole investigation, which only I desired to supply.

‘“‘T may be allowed to express my great satisfaction at finding that the
different parts, written at intervals during seven years, harmonize so well
as they do. There would have been nothing particular in this, if the parts
had related only. to matters well ascertained before any of them were writ-
ten :—but as each professes to contain something of original discovery, or
of correction of received views, it does surprise even my partiality, that they
should have the degree of consistency and apparent general accuracy which
they seem to me to present.

“ T have made some alterations in the text, but they have been altogether
of a typographical or grammatical character; and even where greatest,
have been intended to explain the sense, not to alter it. I have often added
Notes at the bottom of a page, for the correction of errors, and also the
purpose of illustration : but these are all distinguished from the Original
Notes of the Researches by the date of Dec. 1838.

“ The date of a scientific paper containing any pretensions to discovery
is frequently a matter of seriotis importance, and it is a great misfortune
that there are many most valuable communications, essential to the history
and progress of science, with respect to which this point cannot now be as-
certained. This arises from the circumstance of the papers having no dates
attached to them individually, and of the journals in which they appear
having such as are inaccurate, i. e. dates of a period earlier than that of
publication. I may refer to the note at the end of the First Series, as an
illustration of the kind of confusion thus produced. These circumstances
have induced me to affix a date at the top of every other page, and I have
thought myself justified in using that placed by the Secretary of the Royal
Society on each paper as it was received. An author has no right, perhaps,
to claim an earlier one, unless it has received confirmation by some public
act or officer,”

In connexion with the general subject of the volume, Mr. Faraday
then alludes to his papers on Electro-magnetic Rotations in the
Quarterly Journal of Science for 1822, and on Magneto-electric
Induction in the Annales de Chimie, vol. li., which, he remarks,
“might, as to the matter, very properly have appeared in this volume,
but they would have interfered with it as a simple reprint of the
‘ Experimental Researches’ of the Philosophical Transactions.” He
next refers in relation to the Fourth Series of his own Researches,
on a new law of electric conduction, to Franklin’s experiments on
the non-conduction of ice as brought forward by Professor Bache, .
observing, ‘‘ These, ........ though they in no way anticipate the
expression of the law I state as to the general effect of liquefaction
on electrolytes, still should never be forgotten when speaking of
that law as applicable to the case of water.”

“ There are two papers which I am anxious to refer to, as corrections or
criticisms of parts of the Experimental Researches. The first of these is

{

Experimental Researches in Electricity. 471

one by Jacobi, (Philosophical Magazine, 1838. xiii. 401.) relative to the
possible production of a spark on completing the junction of the two metals
of a single pair of plates (915.). It is an excellent paper, and though I
have not repeated the experiments, the description of them convinces me
that I must have been in error. The second is by that excellent philosopher,
Marianini, (Memoria della Societa Italiana di Modena, xxi. 205) and is a
critical and experimental examination of Series viii. and of the question
whether metallic contact is or is not productive of a part of the electricity
of the voltaic pile. I see no reason as yet to alter the opinion I have given ;
but the paper is so very valuable, comes to the question so directly, and the
point itself is of such great importance, that I intend at the first opportunity
renewing the inquiry, and, if I can, rendering the proofs either on the one
side or the other undeniable to all.

Other parts of these researches have received the honour of critical at-
tention from various philosophers, to all of whom I am obliged, and some
of whose corrections I have acknowledged in the foot notes. There are, no
doubt, occasions on which I have not felt the force of the remarks, but time
and the progress of science will best settle such cases; and, although I
cannot honestly say that I wish to be found in error, yet I do fervently hope
that the progress of science in the hands of its many zealous present culti-
vators will be such, as by giving us new and other developments, and laws
more and more general in their applications, will even make me think that
what is written and illustrated in these experimental researches, belongs to
the by-gone parts of science.”

An analytical table of contents succeeds the preface, which, on ac-
count of its general utility and as furnishing a clew to the distribu-
tion, through the Fourteen Series, of the several objects of specific
research, we shall transfer to our pages.

“ Series I. §. 1. Induction of electric currents. §. 2. Evolution of elec-
tricity from magnetism. §. 3. New electrical state or condition of matter.
§. 4. Explication of Arago’s magnetic phenomena.

“Series II. §. 5. Terrestrial magneto-electric induction. §. 6. Force
and direction of magneto-electric induction generally.

“Series III. §. 7. Identity of electricities from different sources. i. Vol-
taic electricity. ii, Ordinary electricity. iii. Magneto-electricity. iv. Ther-
mo-electricity. v. Animal electricity. §. 8. Relation by measure of com-
mon and voltaic electricity. Note respecting Ampére’s inductive results
after.

‘Series IV. §. 9. New law of electric conduction. §. 10. On conducting
power generally.

“Series V. §. 11. Electro-chemical decomposition. { J. New condi-
tions of electro-chemical decomposition. | 2. Influence of water in such
decomposition. §j. 3. Theory of electro-chemical decomposition.

* Series VI. §. 12. Power of platina, &c. to induce combination.

“Series VII. §. 11. Electro-chemical decomposition continued (nomen-
clature). 4% 4. Some general conditions of electro-chemical decomposition.
@ 5. Volta electrometer. J 6. Primary and secondary results. | 7. De-
finite nature and extent of electro-chemical forces. Electro-chemical equi-
valents. §. 13. Absolute quantity of electricity in the molecules of matter.

“Series VIII. §. 14. Electricity of the voltaic pile. {J 1. Simple vol-
taic circles. 2. Electrolytic intensity. {J 3. Associated voltaic circles;
or battery. {J 4. Resistance of an electrolyte to decomposition. J 5. Ge-
neral remarks on the active battery,

“ Series IX. §. 15. Induction of a current on itself. Inductive action

of currents generally.

4ATZ Scientific Memoirs. Part V.

“Series X. §. 16. Improved voltaic battery. §. 17. Practical results
with the voltaic battery.

“Series XI. §. 18. On static induction. J 1. Induction an action of
contiguous particles. § 2. Absolute charge of matter. {J 3. Electrometer
and inductive apparatus. § 4. Induction in curved lines. Conduction by
glass, lac, sulphur, &c. {J 5. Specific inductive capacity. [ 6. General
results as to the nature of induction. Differential inductometer.

“Series XII. | 7. Conduction or conductive discharge. { 8. Electro-
lytic discharge. J 9. Disruptive discharge; insulation ; as spark ; as brush;
positive and negative.

“Series XIII. Disruptive discharge as glow; dark. | 10. Convection ;
or carrying discharge. {J 11. Relation of a vacuum to electrical phenome-
na. §. 19, Nature of the electric current; its transverse forces.

“Series XIV. §. 20. Nature of the electric force or forces. §. 21 Re-
lation of the electric and magnetic forces. §. 22. Note on electrical exci-
tation.”

Next follow in order the ‘“ Experimental Researches in Electri-
city,” from the First to the Fourteenth Series, illustrated by the
original engravings, from the Philosophical Transactions.

The volume concludes with a copious and minutely particular
index, occupying eighteen pages, and presenting, in fact, a complete
analysis of the objects and results of the author’s “ Researches”
contained in this work. This we are enabled to say from our own
acquaintance with those ‘‘ Researches,” and examination of the in-
dex ; which has also the recommendation of having been, as we
happen to know, constructed by the author himself, a recommenda-
tion which every one having any practical experience in the biblio-
graphy and history of science and scientific discovery will know how
to estimate.

As the Fifteenth Series of Mr. Faraday’s Researches has already
been read before the Royal Society, and will appear in the forth-
coming part of the Philosophical Transactions, it is evident that his
devotion to the subject is still unremitting, and we earnestly wish
him health and happiness yet further to develope the laws of elec-
trical action, hoping tc have the pleasure of announcing to our
readers, in due time, the publication of another and similar collection
of his ‘‘ Experimental Researches in Electricity,” in sequence to the
present volume.

LXX. Intelligence and Miscellaneous Articles.
SCIENTIFIC MEMOIRS, PART V.

ART V. of the Scientific Memoirs, being the first of the second

volume, is just ready for publication. It commences with a paper
by Jacobi on some Electro-Magnetic Experiments, forming a sequel to
the Memoir on the Application of Electro-Magnetism to the Move-
ment of Machines, of which a translation appeared in the first vo-
lume. The second article is one the importance of which will be
readily appreciated at the present time; it is a translation, revised by
Professor Lloyd and Major Sabine, of the ‘‘ Results of the Observa-
tions made by the Magnetic Association in the year 1836,” edited

a

.

Intelligence and Miscellaneous Articles. AT3

by Professors Gauss and Weber, being the First Annual Report of
the Magnetic Association. An introduction, from the pen of Gauss,
on the Irregular Variations of the Terrestrial Magnetic Force, is
succeeded by ‘‘ Remarks on the Arrangement of Magnetical Obser-
vatories, and Description of the Instruments to be placed in them,”
by Weber; which is followed by a minute account of the “‘ Method
to be pursued during the terms of Observation,’ by Gauss. This is

succeeded by an “ Extract,” also by Gauss, “from the daily Obser-

vations of Magnetic Declination during three years at Gottingen,”
and a “ Description of a small portable apparatus for measuring the
absolute intensity of Terrestrial Magnetism, and Explanations of
the six graphical Representations and of the Table of Results.”
Our readers will remember the Report to the Council of the Royal
Society of a Joint Committee of Physics and Meteorology ‘‘ on the
establishment of fixed Magnetic Observatories and the equipment of
an Antarctic Expedition for Magnetic Observations,” which appeared
in the Philosophical Magazine for February last, and to which we
may refer those who may not have already become acquainted with
the value and bearings of the work of Gauss and Weber, which now
first appears in the English language.

The Part, which is illustrated by Ten Engravings, also contains
a highly valuable memoir by Professor Heinrich Rose on the Com-
binations of Ammonia with Carbonic Acid; and another by Melloni
on the Polarization of Heat.

PREPARATION OF DICHLORIDE OF CARBON. BY M. REGNAULT.

M. Regnault prepared the proto-chloride of carbon, which, how-
ever, according to French equivalents, is described as CCl2, accord-
ing to Faraday’s process ; he states that he found its boiling point to
be 248° instead of 170°, as mentioned by Faraday; the density of
the vapour he ascertained to be 5°8, and therefore he considers it as
composed of C# Cl8, and it belongs, he says, to the series of chloride
of aldehyde,—that is, to a series of which it contains only two out of
three elements,—but then this is explained by the doctrine of substitu-
tions—‘C’ est I’hydrogéne bicarboné C+ H8, dans lequel Phydrogéne
est remplacé par son équivalent de chlore.” It appears to me that it
would be quite as consistent with sound philosophy, and attended
with the additional advantage of somewhat extending the doctrine of
substitutions, if we were to say, that water belongs to the series of
sulphurets of mercury in which the sulphur is replaced by its equivalent
of oxygen, and the mercury by its equivalent of hydrogen.

M. Regnault appears, however, to have succeeded in preparing the
dichloride of carbon, a specimen of which, as an accidental product,
was examined by Mr. Faraday and myself. He procured it by re-
peatedly passing the proto-chloride through a tube heated to red-
ness; the dichloride condenses in the coldest parts of the tube in
very fine silky needles, which are to be separated by ether; when
resublimed it is quite pure. This substance is nearly inodorous ; it
is difficult to hit upon the exact degree of heat for its preparation ;
if it be too great, the decomposition is complete and charcoal is de-
posited,—R. P. An. de Ch, et de Ph, \xx., 105.

474 Intelligence and Miscellaneous Articles.

DELVAUXENE—A NEW PHOSPHATE OF IRON.

This mineral was first found in 1793, at Berneau, near Visé; it
occurs in brittle reniform masses, its texture is compact, and its frac-
ture perfect conchoidal. It is opake or only slightly translucent
on the edges of thin fragments; its lustre is sometimes resinous ;
sometimes it is dull; colour blackish or reddish brown, but some-
times yellowish brown ; the powder is of a yellowish brown, and the
finer the brighter. Its hardness is intermediate as to that of calca-
reous spar and sulphate of lime: specific gravity 1°85. When heated
in a flask it yields much water, and loses 42 per cent. of water when
heated to redness. Before the blow-pipe it decrepitates and fuses
into a grey very magnetic globule of iron.

With borax on a platina wire, in the reducing flame, a bottle-
green globule is obtained, and in the oxidating flame a globule,
which is brownish while hot, and becomes green on cooling. In
water it falls to pieces, effervesces and gelatinizes in hydrochloric
acid, forming a brownish orange solution; the nitric solution gives
a white precipitate with nitrate of lead, and a blue one with ferro-
cyanide of potassium. ‘This mineral was first found in a lead mine,
but it has since occurred in a stone-quarry near the same place. M.
Dumont analyzed both varieties—Ist, reddish brown, 2nd, brownish
black—the results were

No. 1. No. 2.
Phasploric atid ~. >>>. >98°60!.- 2. « 14°30
Peroxide of iron........ QSOO 11st: Ss 31°60
Waten cl 2 Logi ap ilte ot 42:90 baseas x 40°40
Carbonate of lime...... 11°00 ...... 9°20
Billed fhe Nee oA eae: 3°60 rane 4°40

99°40 99:90

Neglecting the carbonate of lime and silica, this mineral is a di-
phosphate of peroxide of iron + 6 eqs. of water; the phosphate of
iron of the Isle of France, analysed by Laugier, differs from the
above in containing only half the quantity of water.

The name of Delvauxene was given to this mineral by M. Dumont
from that of its discoverer M. Delvaux.—L’ Institut, No. 276.

ON THE USE OF AMMONIA IN FIXING PHOTOGRAPHS. BY J. C.
CONSTABLE, ESQ.
To the Editors of the Philosophical Magazine.
GENTLEMEN,

Mr. Fox Talbot, in his paper on photogenic drawing, states, that
he did not succeed in preserving the drawings by means of ammonia ;
some experiments which I have made lead to a different result. I
find that the drawings, after being soaked for some minutes in a
moderately strong solution of ammonia and then washed in clean
water, withstand the action of the light perfectly, and indeed are
improved by it: for the first action of the ammonia is to make the
dark parts of a reddish hue, which, on exposure to the light, become
again of a dark colour, the light parts being unaffected. ‘This mode

:

a

Intelligence and Miscellaneous Articles. 475

of preservation has, I conceive, advantages over those already used.
Common salt never preserves completely so as to enable the draw-
ings to withstand the action of the sun. Iodide of potassium seems
to require great delicacy in management, as when at all too strong
it eats out the fainter tints, and is moreover subject to this incon-
venience—that sometimes the drawings so preserved, even when
kept in the dark, become entirely bleached and lose all traces of the
dark lines. This at least has happened to some drawings so pre-
pared by a friend of mine. There is no doubt that the hyposulphite
of soda is an excellent preservative, but it is a salt not easily pre-
pared and not likely to be in the hands of those who may wish to
make experiments on the subject. If you think these remarks
worth publishing, I shall be obliged by their insertion in your next
number.
I am, Gentlemen, your obedient servant,
J. C. Constasur,

Jesus College, May 21, 1839.

APPLICATION TO PHOTOGRAPHY OF THE LIGHT OF INCANDES-
CENT COKE. BY MR. R. MALLET.

The following is an extract from the Proceedings of the Royal
Irish Academy (No. 16), for April 22nd, 1839:

“Mr. Robert Mallet communicated a notice of the discovery of
the property of the light emitted by incandescent coke to blacken
photogenic paper; and propose it as a substitute for solar light, or
that from the oxy-hydrogen blowpipe with lime.

“One of the most important applications of the photogenic pro-
cess, as yet suggested, is its adaptation to the self-registering of
long continued instrumental observations. Unless, however, an ar-
tificial light of a simple and inexpensive character can be found to
supply the place of solar light at night, the utility of this applica-
tion will be much limited.

“ Few artificial lights emit enough of the chemical rays to act
with certainty on the prepared paper; while those which are known
to act well, as the oxyhydrogen lime light, are expensive and difficult
to manage. A considerable time since the author discovered that
the light emitted by incandescent coke at the ‘'T'wyer’ (or aperture
by which the blast is admitted) of a cupola or furnace for melting
cast iron, contained the chemical rays in abundance ; and on lately
trying the effect of this light on the prepared paper, he found it was
intensely blackened in about forty-five seconds. In the single ex-
periment made, the heat, which was considerable, was not separated
from the light; but the author purposed to make further experiments,
in which this precaution will be attended to.

“There is no difficulty to be apprehended in contriving an appa-
ratus to burn a small quantity of coke at a high temperature. A
diagram of an apparatus for this purpose was shown. It consists of
a vertical tube, nine inches in diameter, lined with refractory clay,
and closed at top and bottom. There is a grating about one foot
from the bottom, a little above which are two opposite holes, into

476 Intelligence and Miscellaneous Articles.

one of which an air blast from a revolving fanner is projected through
the coke, with which the whole tube is filled. The flame passes out
at the opposite hole, through a tube so contrived, as to heat the blast
of air to a temperature of 500°, just before it enters the coke fire.

«The light from the former lateral aperture is that proposed to be
used, and issues through a plate of mica or glass opposite to it. This
aperture forms part of the conductory tube for the blast, which (by
passing into the coke in a direction opposite to that in which the light
is emitted) keeps the illuminating surface of coke clear from ashes ;
these are received below the grating, and by a diversion of part of
the blast, are blown into the chimney which receives the other pro-
ducts of the combustion.

« As the vertical tube is close above, the combustion cannot pro-
ceed upwards, while the coke with which it is filled constantly drops
down to supply the place of that consumed, on the principle of the
ancient furnaces, called ‘athanors’ by the earlier chemists.

«The only difficulty to be apprehended in the use of coke, is the
collection of slag from the fusion of its earthy and ferruginous con-
stituents; however the author does not consider that this accumu-
lation during the period from sunset to sunrise, in mid-winter, would
materially interfere with its action.”

ON THE COMPOSITION OF IDOCRASE. BY H. HESS.

Mineralogists have not yet hitherto agreed as to the composition
of idocrase; only so far is certain, that many consider the chemical
formulz to be the same as that of garnet. Under this idea garnet
and idocrase are considered to be the same substance under two dif-
ferent forms. However this is not the case. Possessing a very fine
crystal of idocrase from Slatoust, I gave it to one of my best pupils,
M. Ivanor, to analyse. The following is the result of his analysis :

Oxygen.
Silica se ere ler 37:07 Svcontaining sx. 2 Sek ele eee 19°262
Alumina....... 14°159 br dcumietiokite 6°612
Baragiceecth. tert 30°884 $3 8644 19°621
Protoxide of iron 16°017 sf 3°646 ~ 13:009
Magnesia ...... 1858 5 0°719
99°997

We therefore possess three mineral species which only vary in the
number of their compounded elements, viz.

Garnet. sa eeiier BR Si + Al Si
Tdocrase’. =<... sje ten 2 R3 Si ce Al Si
POPIAOUE. ens we R? Si + 2Al Si.

There can be no doubt as to the correctness of M. Ivanor’s ana-
lysis, as it was performed under my superintendence and upon a

Intelligence and Miscellaneous Articles. 477

quantity unknown to the analyst. As the different weights agreed
with the original weight of the mineral I had given out for analysis,
no error could have crept into the result.—Poggendorff’s Annalen,
No. 10, 1838.

ON THE COMPOSITION OF IDOCRASE FROM SLATOUST,
BY F. VARRENTRAPP.

Klaproth, von Robell, and particularly Magnus, have shown, after
very careful analysis, that idocrase and garnet have the same che-
mical composition. Notwithstanding that every attention has been
directed to find an essential chemical difference to account for the va-
riation in the crystalline form, it has been hitherto im vain. Ivanor’s
analysis, as reported in the Transactions of the St. Petersburg Aca-
demy, of an idocrase from Slatoust in Siberia, has attracted attention,
as the result is not in accordance with that of other chemists, and
the difference is such as to require a different formula. The locality
was the same as the idocrase examined by Magnus. G. Rose having
brought a quantity of this mineral from Siberia, Mr. F. Varrentrapp
repeated the analysis, with the following results :

Varrentrapp. Magnus. Ivanor.
papa Slur ices. ae S7Sb 9 eee SUPUABM ANAS. 37°079
Admmina 43.6 3/35<:. Wi <S Blithe hanes VS O72 .-5 2) L459
Ihime ses, AF is, , RODEO Gs: es): Jor IO tae 30°884
Protoxide of iron.. 6°34 ...... AGT Ds 16017
Magnesia ....... ZOD sare = tei 2268 ie Weds 1°858

99°95 98°024 D907

The mineral consisted of well-formed transparent green crystals
imbedded in felspar, from which they were easily separated, exactly
the same as those described by Magnus in his analysis. The cry-
stals were carefully selected, reduced to fine powder, heated with car-
bonate of soda, and examined in the usual manner. The great dif-
ference in the results between M. Varrentrapp and M. Magnus on
the one side, and M. Ivanor on the other, is difficult to account for.
It may have arisen in M. Ivanor’s analysis in the use of too small a
quantity of potash in the separation of the alumina from the oxide
of iron, which would give a larger proportion of oxide of iron and a
smaller one of alumina ; the deficiency in the quantity of lime may
have arisen from not having quickly enough filtered the solution
after precipitating by ammonia.

Fuchs observed as long ago as in 1818, that idocrase, as well as se-
veral other minerals containing an alkali or an alkaline earth, when
- subjected to a strong heat and fused, were capable of being decom-

posed by hydrochloric acid, forming a gelatinous mass. Von Robell
and Magnus confirmed this observation, and the latter further ob-
served that the specific gravity of idocrase after fusion was con-
siderably diminished, although no alteration in the composition could
be discovered.

- M. Varrentrapp in making a second analysis of this mineral first
fused it ; he obtained a good flowing clear glass of a brown colour, of

478 Intelligence and Miscellaneous Articles.

which a portion was reduced to powder and acted upon by hydro-
chlorie acid, which soon brought it into a gelatinous state. The re-
sult of this analysis was

STULL CHS, Mie a 2 << Beate 37°84
PAUOAING |, <.. aace-wneetirece oe 17°99
Dime) ho hoc Men edhe
Protoxide of iron........ 6°45
Magnesia. onc epistie das 2°81

100°27

The mean specific gravity from four weighings of the crystallized
idocrase was 3°346, that of the fused, agreeing with Magnus, was
2°929—2°941.—Poggendorf’s Annalen der Physik und Chimie, No,

10, 1838.

TERRESTRIAL MAGNETISM.

In a memoir presented by M. Quetelet to the Royal Academy of
Brussels, in which he examines the results of the observations which
he has made during twelve years upon the state of terrestrial magne-
tism at Brussels, the result of the whole of these observations is
stated to be, that the magnetic needle has been constantly approach-
ing the meridian line, that is to say, that the declination and the dip
have diminished from year to year, contrary to what had been ob-
served before, at least as to magnetic declination. The results ob-

served were as follows:

Date. Declination. Dip.
| SOU es Octoherices.sice ia 22°28'8 | 68°56,5
) 1830 end of March... . 22 25,3 | 68 52,6
| 1832 i> Ae ie 22 19,0 | 68 49,1
| 18338 i De eth |e 22, eee) Oenistaee
| 1834 beginning of April | 22 15,2 | 68 38,4
| 1835 end of March.... | 22 6,7 | 68 35,0
| 1836 st ery std eon (OBBMES
1837 i dpa ee 438-68: 2858
1838 - sate Oo Seika HOS Os
1839 js teats 21 58,6 | 68 22,4

This year’s observations for the declination were made on the 29th
of March. ‘The value indicated is the mean of two series of obser-
vations, which gave successively 21°53/,1 and 21°54',2. Similar ob-
servations had been made the evening before, in less favourable cir-
cumstances, on account of the agitation of the air. The latter had
given for the declination 21°51',3 and 21°51',1: it was thought that
preference should be given to the former. In these different series
of observations the meridian was determined by placing the mag-
netic apparatus previously in such a manner that the telescope might
be directed at pleasure on the middle wire of the transit of the ob-

servatory.

Meteorological Observations. 479

The value of the dip is the mean of the three following amounts,
68°22',95, 68°22! 67, and 68°22’,25, obtained in succession on the
31st of March. These observations were made under very favourable
circumstances. As in preceding years, it was thought proper tc
make the different observations for the declination and the dip at
the same time of year and about the same hours of the day.

NOTE ON THE UNDULATORY THEORY OF LIGHT.
BY JOHN TOVEY, ESQ.
To the Editors of the Philosophical Magazine.
GENTLEMEN,

I perceive that the formule (18) of my paper in your present vol.,
p- 171, appear to lead to contradictory results; I shall be glad,
therefore, if you will allow me to say, that this matter will be cleared
up in my next paper, which will contain an improved method of find-
ing the general integrals.

I am, Gentlemen, yours, &c.,
Joun Tovey.
Littlemoor, Clitheroe, May 13th, 1839.

METEOROLOGICAL OBSERVATIONS FOR APRIL, 1839.

Chiswick.— April 1, Rain. 2. Overcast. 3, 4. Bleak and cold. 5. Snow-
ing. 6. Cloudy andcold. 7. Fine. 8. Snowing. 9. Bleak andcold. 10,
11. Fine but cold. 12—14. Cloudy andcold. 15. Overcast. 16. Very fine.
17. Showery. 18. Boisterous with rain. 19. Very fine. 20. Showery. 21.
Fine. 22. Very fine. 23. Rain. 24—926, Fine, 27. Dry haze. 28—80,
Very fine.

Boston.—Aprill. Fine. 2. Stormy. 3—7. Cloudy. 8. Cloudy: sleet early
am. 9. Cloudy. 10. Fine. 11—I15. Cloudy. 16. Fine. 17, 18. Rain.
19. Fine: rain early am. 20,21. Fine: rain a.m.andr.m., 22, Fine: rain
earlya.m. 23. Rain. 24—26. Cloudy. 27. Cloudy: raina.m. 28—30. Fine.

Applegarth Manse, Dumfries-shire—April1. A most inclement day: snow on
hills. 2. The same: snow on hills melting. 3. The same: bitterly cold. 4.
Another piercing day: cloudy y.m. 5. Still extremely cold: snow showers. 6.
Wind fallen : more temperate. 7. Moderate day: stillno vegetation. 8. Pier-
cingly cold and withering, 9. Dry and cold: frosty mornings. 10. Sun warm,
but wind cold and withering. 11. Milder, but still no spring. 12. Great in-
crease of temperature. 13. Sun warm: wind moderate but parching. 14. Mo-
derate day: vegetation commencing. 15. The same: temperature lower :
cloudy. 16. Threatening rain: showery: very wet p.m. 17. Showers: rain:
hail: cleared p.m. 18, Frequent showers: rainand sleet: snow. 19. Violent
wind : showers of hail. 20. Dry and cold: vegetation ata stand. 21. Dry:
temperature rising. 22. Foggy morning: drizzlingday. 28. Clear: tempera-
ture increasing. 24. The same: coolevening. 25. Temperature increasing :
clearsun. 26. Cloudy: threatening. cleared up r.m. 27. Clear and fine :
hoar frost morning. 28. The same: cloudyr.m- 29. Fine springday. 30.
Remarkably fine spring day.

Sun 25 days. Rain 4 days. Snow 2 days. Hail2days. Frost 3 mornings.
Wind easterly 13 days. Southerly 12 days. Northerly 2days. _ Westerly 3
days. ,

Calm 11 days. Moderate 7 days, Strong breeze 4 days. Stormy 5 days,
Brisk 3 days.

Mean daily range of barometer 0:092._ Mean nightly range 0°080, Mean
range of 24 hours 0°172,

Mean daily range of thermometer 10°4,

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THE
LONDON anv EDINBURGH

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE,

SUPPLEMENT ro VOL. XIV. THIRD SERIES.

LXXI. Onthe Expansive Action of Steam in some of the Pump-
ing Engines on the Cornish Mines. By Wititam Jory
Henwoon, F.G.S., Secretary of the Royal Geological Society
of Cornwall, H. M. Assay-Master of Tin in the Duchy of
Cornwall*,

‘PHE experiments which it is my purpose to describe, were
instituted with a view to the determination of the quan-
tity of steam employed, and the mode of its distribution on
the working stroke; the duty performed with a given quan-
tity of fuel; and the work accomplished for a certain expense.

I. The quantity of steam employed, and the mode of its dis-
tribution on the working stroke, were approximated to by the
use of an indicator, lent me for the purpose by Robert Were
Fox, Esq. It consists of a brass cylinder about 11 inches
long, and 1°6 inch in diameter, open at both ends, and accu-
rately fitted with a piston, which, when at rest, is retained
near the middle of the cylinder by a spiral spring, of which
one end is attached to the piston, and the other to the top of
the cylinder: the upper extremity of the piston-rod is pro-
vided with a receptacle for a pencil. A tapered stop-cock is
fixed on the lower end of the cylinder, and is introduced into
the grease-hole or other aperture in the cylinder-cover of any
engine on which the indicator is placed. A light frame of
wood, about 18 inches long and 4 inches wide, is fastened to
the top of the indicator-cylinder, and in it a small board slides
horizontally in grooves.

During the working stroke of the engine a direct motion
is given to the slider by means of a string which passes over
a pulley, and is connected with the radius-rod of the parallel
motion. Its return is effected by the action of a counterpoise
suspended over a similar small wheel. On this moveable
board a piece of paper is firmly secured, and a pencil is placed
on the top of the piston-rod of the indicator.

* The Telford Medal of the Institution of Civil Engineers was awarded
to this communication, which appears in the second volume of their
Transactions,

Phil, Mag. 8, 3, Vol, 14, No. 92, Suppl. July, 1839. 21

482 Mr. Henwood on the Cornish Pumping-Engines.

Let us now examine the operation of a single-acting engine,
and the movements of an indicator fixed on it.

Every thing being at rest, the piston of the engine at the
top of the cylinder, and the point of the pencil standing at A,
(in the figure below) steam is admitted from the boiler above the
piston of the engine; the piston of the indicator is forced up-
wards, and the line A B is described by the pencil. The en-
gine now begins to move, but so slowly that the steam enters
from the boiler more rapidly than the piston recedes before
it; its pressure in the cylinder, therefore, still increases, and
the piston of the indicator continues to rise: but as the work-
ing stroke of the engine commences, the slider moves in the
direction GF, and the compound of the two motions generates
the line BC. At C the space left by the descent of the pis-
ton is exactly filled by the steam, which enters from the boiler
in the same time; the indicator-piston, therefore, does not
stir; but as the engine moves, the slider still advances in the
same direction, (GF) and the horizontal line Ce is produced.
The piston now acquires speed, whilst the steam (in the boiler
having expanded) enters the cylinder with diminished velo-
city, and is insufficient to fill the enlarging space and still re-

ec

tain the same density: it therefore expands, and the piston
of the indicator descends, whilst the slider still moves in the
same direction, and the curve cD is delineated. At D the
steam valve, through which the steam from the boiler enters
the cylinder, is closed, but the piston of the engine still de-
scends by virtue of the elasticity of the steam already
introduced, and of the momentum acquired by the moving
parts of the machine. Whilst the steam expands, the indi-
cator-piston descends, and as the same horizontal motion of
the slider still continues, the parabolic curve DE is made by
the pencil.

The equilibrium valve, which connects the upper part of
the cylinder with the lower, is now opened ; and as the steam
thus presses equally on both sides of the piston, the working
stroke terminates, and the return stroke is made: the motion
of the slider is at the same time reversed,

——

— ee yee

Mr. Henwood on the Cornish Pumping-Engines. 483

But when this valve is opened, the pipe which connects the
top of the cylinder with the bottom, and consequently a larger
space, is open to the steam, and as the slider remains for the
instant stationary, the indicator-piston descends through the
small vertical line EF.

The return stroke is effected by the weight of the pump-
rods alone; the pressure of the steam contained in the cylin-
der, therefore, remains unaltered, the indicator-piston is un-
moved, and the line FG, described by the pencil, is perfectly
horizontal.

But shortly before the termination of the return stroke, the
equilibrium valve is closed, and the steam in the cylinder net
being of sufficient elasticity to sustain the load of the engine,
that portion of it which is contained between the upper sur-
face of the piston and the cylinder-cover is compressed be-
tween them by the ascent of the former, until it is of force
enough to support that weight; the return stroke is thus ter-
minated, and the engine stops an instant or two before it
commences another working stroke. This compression of
the steam contained in the upper part of the cylinder forces
the indicator-piston upward, and the resultant of this gradual
elevation, and of the continued retrograde motion of the
slider, is the small curved line GA, the pencil at the end of
the stroke returning to and standing at A.

It is evident that the form of the portion ABCcD, which
is produced during the admission of steam from the boiler on
the piston, must depend on the load of the engine, its size, the
dimensions of the steam valve, the pressure of steam in the
boiler, and the capacity of the boiler itself, and that it will,
therefore, vary as these particulars may differ.

The part DzE will deviate from a true parabola only when
the steam in the cylinder is heated by being surrounded by a
steam-case, or jacket, or by flues containing warm air, or
cooled by the influence of the circumambient medium; con-
sequently it will be generally pretty much alike in all cases.
The same reasons and influences are equally applicable to the
small and nearly vertical line EF, and to the longer horizon-
tal one FG.

But, theoretically speaking, the curve GA is of more im-
portance than any other portion of the figure; because it
clearly shows what proportion of the working stroke is per-
formed by the beneficial influence of working expansively.

For were the steam from the boiler admitted on the piston
during the whole of the working stroke, or the pressure of
the steam (if worked expansively) sufficient to support the
load at the termination thereof, then the line I'G, described

212

484 Mr. Henwood on the Cornish Pumping-Engines.

by the return stroke, would be prolonged horizontally until
it intersected an extension of the vertical line AB at x; at
which point the pencil would rest at the end of the return
stroke, and the instant the equilibrium valve closed the engine
would stop. But it has been seen that the engine continues
to move, and that the indicator-piston rises and generates the
curve GA, after that valve is closed: which circumstances
clearly demonstrate that the steam included between the cy-
linder-cover and the upper surface of the piston, is meanwhile
undergoing compression ; and that its elasticity both at the
conclusion of the working stroke, and at the closing of the
equilibrium valve, was insufficient to sustain the load. And
it follows, that the portion of the working stroke which has
been performed after the steam has expanded so much as to
be unequal to supporting the burden, must have been accom-
plished by the momentum acquired in the early part of the
stroke. When the pencil rests at A, the force of the steam
balances the load of the engine; for the piston is never per-
mitted to rise so far as to touch the cylinder-cover. If, there-
fore, from A a line be drawn parallel to FG, until it cuts the
parabolic curve DE, the point of intersection, ~z, will be at that
part of the stroke where the (simple) elasticity of the steam
and the load of the engine are exactly in equilibrio; and the
portion zE, (described after the steam has so far expanded as
to be insufficient to support the burden,) will denote the
amount of benefit obtained by working expansively.

The only case in which I have been able to submit the re-
sults thus obtained with the indicator to a direct comparison
with the quantity of water evaporated in the boilers was at
Huel Towan, where 847°5 cubic feet of water were converted
into steam. ‘This would give 342,858 feet of steam of a
pressure of 64°1 lbs. on the square inch, (or 49-1 lbs. on the
inch above the atmosphere,) the mean pressure in the boiler
during the experiment, or 2,153,647 cubic feet of the press-
ure of 10°2 lbs. on the inch*. The capacity of the cylinder-
nozles and other parts of the engine which required to be
filled with steam from the boiler at every stroke, was 355°57
cubic feet}, and the number of strokes made during the ob-
servations 7881. ‘Therefore, if it were indispensable for the
steam on the piston, at the termination of the working stroke,
to be of elasticity sufficient to sustain the load of the engine,

_* 10°2 lbs, was the load of the engine per square inch of the area of the
piston.
+ Brewster’s Edinburgh Journal of Science, O. S. IX. p. 160; from this,
abe tlt ee dimensions of the piston-rod, probably about 2 cubic feet,
should be deducted,

Powe

Mr. Henwood on the Cornish Pumping-Engines. 485

2,802,247 cubic feet (of a pressure of 10:2 lbs. on the inch)
would have been requisite; whereas but 2,153,647 cubic feet
only could be obtained from the quantity of water evaporated.
Consequently but the 0-768th of the contents of the cylinder,
&c., could, on an average, have been filled with steam of that
force; and the remaining 0°232 of the stroke must therefore
have been performed by virtue of the momentum acquired by
the machine in the early part of the working stroke.

This 0°232 part of the whole is therefore the benefit ob-
tained by working the steam expansively ; although the result
obtained by the indicator exhibits a still greater (about 0°388)
advantage. ‘The cause of this difference it is not very easy to
assign satisfactorily. It is just possible that it may be from
the fluctuating pressure of the steam (from 77°25 to 47:22 lbs.
on the inch) during the experiment, giving a result differing
on a mean more than 61°8 lbs. on the inch, (the force when
the curve represented in the figure p. 482 was obtained,) does
from the average elasticity during the observation (64°1 Ibs.).
But perhaps it may more probably be from the steam, even
when expanded to a less forcethan 10-2 lbs. on the inch, still ex-
ercising a beneficial influence in assistance of the momentum by
which the latter part of the working stroke is performed.

In a first attempt at such a comparison, which I believe is
here made, it may perhaps excite no great surprise that there
is not a more exact coincidence between the results obtained
by these very different modes of inquiry.

Il. The duty performed with a given quantity of fuel.—The
experiments with an object to determining the duty performed
with a known quantity of fuel, were made on Wilson’s engine
at Huel ‘Towan; on Swan’s engine at Binner Downs Mine;
and on Hudson’s engine at East Crinnis Mine*. These
were among the best engines in Cornwall, and they were se-
lected on account of the very varied circumstances under which
they worked.

At Huel Towan the cylinder with its cover and bottom
were surrounded with a case or jacket, filled with dense steam
from the boiler; and these, with the steam-pipes, nozles, &c.,
were covered with saw-dust from 16 to 20 inches deep. The
boilers had a layer of ashes, of about the same thickness,
placed on them.

There was no steam-case at Binner Downs, but there were
small fires on each side of the cylinder, and the flues from
them were carried spirally round it; another little fire was
placed beneath the steam-nozle, from the boiler, and its flue

* The engineers were respectively, Mr. Grose, Messrs. Gregor and
Thomas, and Mr. Sims.

486 Mr. Henwood on the Cornish Pumping-Engines.

was passed over the cylinder-cover; under the steam-pipe
from the boiler was a similar fire, and its smoke was conveyed
round the pipe for some distance. Such parts of the engine
as were not enveloped by the flues were surrounded with
saw-dust*, and the boilers were covered with ashes as at
Huel Towan.

The engine at East Crinnis had neither steam nor heated
air passed round it; but every part which contained dense
steam was surrounded with a very thick covering of saw-dust,
and the boilers were protected in a similar manner to those
of the other engines.

On all these the indicator was placed; and also on Burn’s
engine at Binner Downs, which is inclosed in a similar man-
ner to Swan’s engine on the same mine, already mentioned ;
and on Trelawny’s and Borlase’s engines at Huel Vor, both
which have steam-cases and other coverings like that described
at Huel Towan. On the duty of these no experiments were
made.

Tasie I.—(Constants.)

Dimensions of the Engines, and amount of their loads.

: : Diameter of :
% ‘ Stroke in Air-pump. waltth 8 5 g
, : gs so | Total load ached
Mines and Engines. os ; as S of the Bos
8 >: |Cylin- Dia- | strok A 4 B | 2 Engine aie}
Ao | der. Pump.| meter. geese 2 | 5 AS Benes 3 Ps
Rie rae Ca Pe dF Lad Seg Haw ee a HS
In. | Feet. | Feet. Inches. Feet. | In. | In. | In, Ibs. lbs
Huel Towan, Wilson’s| 80 |10 8 36 4 121161) 68666-4 10-2
Binner Downs, Swan’s| 70 |10 | 75 33 | 4 | 9 | 12] 16 eee al } ae
eS urtt §) 004) | Stool, ao 25 466) 7 | 12) 13) 41345 10°7
BastCrinnis, Hudson's} 76 {10-25 /7-16 | two, each Las |10 | 1416] 740861 | 11-4
Huel Vor, Trelawny’s| 80 10 | 7°5 { ity a bss 9 | 14116} 98770 7t
Borlase’s| 80 [10 | 8 | oe }a 10 | 14] 16] 76010 121t

* In the progress of my experiment, the saw-dust on the cylinder-cover
ignited several times. The influence exercised on the steam within the
cylinders by the media with which they were surrounded, may be discovered
by an inspection of the diagrams. (Trans. Inst. C.E. Vol. ii. Figs. 4., &c.,
Pl. IV.

t The stroke in this pump is but 5°65 feet.

+ From Captain Lean’s “ Monthly Reports.”

ante

————

Mr. Henwood on the Cornish Pumping-Engines.

‘Tasie II].—(VanrraB.es.)

487

Quantities of watcr and steam, pressures of steam, and tempera-
tures.

Pressure of Steam

Water in Boil- | Ste in Boilers*.|| ; T t f
ers*, “Cubic fect. “Cubic feet, cele ete anon Baewellt,
Mines and Engines. 5 a :
3 a) ov na oO 22
S°| Are ia {Sal eis See lie ies
Huel Towan, Wilson’s|1096| 9384/1080) 796 | 684 | 700 |/77-25 |47-25 |64°1 |100°5| 90 [93-8
Binner Downs, Swan’s| 686) 586] 636) 400 | 300 | 350 ||74°78 |58-07 |67'87 || 98 | 84 |89-24
—_————, Burn’s 884 230 55
EastCrinnis, Hudson’s|2000|1820/1920)| 730 | 550 | 650 ||36°82 |26°32 31°68) 90 865 |88°2
Huel Vor, Trelawny’s 1164 792 AT oe 82
, Borlase’s 2290 734 40
T t f
Minesand Engines. | “Condensing || "Super'thea”” || “ngfectroom., | "™Reraur aig!
Huel Towan, Wilson’s|66°3 | 62 |64°72 ||78°5 \74°75 |76 (177-5 | 70 | 75°28 |56°5 [52°5 | 53-84
Binner Downs, Swan’s|56 =| 50 |52°32 ||108 |73°75'|76 = ||73 64 | 66°48 [56-5 |49 52°56
$$, Burn’s
?
East Crinnis, Hudson’s|67'5 | 66 |67 68 |64°5 |66:2 ||/64 55 }61:8 |50 (40°75 | 45
Huel Vor, Trelawny’s
, Borlase’s

Note to Table Il.

The following are the dimensions of the heating surfaces of the boilers
of the three engines which were the principal subjects of my experiments.
I add those of Loam’s engine, on the United Mines, (with which I have
been favoured by William Francis, Esq., the scientific director of that ex-
tensive mining establishment,) as the only machine the evaporation in which

has been published.

Society's Transactions, IV. (1836) p. 34.

Mines and Engines.

Area of the
Fire-grates,

Surface exposed
to action of
the flame,

See Mr. Lean’s Report in the Cornwall Polytechnic

Total heating
Surface exposed.

Feet, Feet. Feet.
Huel Towan, Wilson’s Engine. 72 114 2600
Binner Downs, Swan’s ........+ 48 76 1440
East Crinnis, Hudson’s ......... 375 57 2500
United Mines, Loam’s ......... 49°5 98 2310

Loam’s engine, at the United Mines, has the steam cylinder of 85 inches
in diameter, the stroke in it is 10 feet, and in the pump 7°5 feet; the load
is about 12 lbs. per square inch of the area of the piston, and the velocity
about 4°8 strokes per minute: the elasticity of the steam employed I am

* The boilers were, of course, always full of water and steam; and as the
quantity of one increased, that of the other diminished, and vice versa.

+ As the pressure of the steam in the boilers increased, the temperature
of the hot-well declined; so that by observing the alteration in one, that
of the other could be predicted with great certainty.

488 Mr. Henwood on the Cornish Pumping-Engines.

unable to state. From the 2nd of March to the 5th of August, 1836, the
duty was about 65 millions of pounds lifted one foot, by 100 lbs. of coal,
and the evaporation by the same quantity of fuel for the same period was
15°4 cubic feet. This is a sufficient approximation to the result which I had
five years previously obtained at Huel Towan.

The stroke in the cylinder of Loam’s engine is estimated at 10 feet ; an
apparatus is fixed on it for registering the actual space passed over, and the
mean for five months was 9°913 feet.

Taste III.—(Consrants.)
Dimensions of the Pumps.

Huel Towan, Wilson’s Binner Downs, Swan’s | East Crinnis, Hudson’s|

: Engine. Engine. Engine.
| a | oh
é | So)log
Length| Diame-|Temper-|| Length | Diame- |Temper-|| Length | 53 | 32
of ter of jature of|| of ter of | ature of of $6| 8%
Pump. | Pump. |water in|| Pump. | Pump. |water in|| Pump. | 2 g,| 3-2
Feet. | Inches. |Pump *.|| Feet. | Inches.|Pump*.|| Feet. | & g'| °S
ASZ\Sa
BETS Soren Coma, G\AE
First lift, or set of pumps, 5 °
from the surface ...... 265°75 |13 71°125 || 21°254}10° 89:24t|| 39°16 | 13 63
Second seo ea tec ro 263°75 115°875 71°75 |/242°66 |18°875 | 725 || 159-25 | 18 | 63
(bid er cr caceonecarecest ee 197°75 }16°125 |71°875 | 269°66 | 18 | 63
MOUtihcreaecrswecweouneewe 113°66 |16°125 |72°25 198°583| 17 | 62°5
The deepest, which
reaches to the bot- |
tom of the shaft....... 58°16 |12°5 |74 \248 177125 | 74 73°25 | 14 | 63
The whole Joads of the three engines of which it was in-
tended to ascertain the duty were raised perpendicularly, ex-
cept the deepest lift of Wilson’s engine at Huel Towan; and
this was inclined to the horizon about 70°, and was connected
to the engine-rod by a chain passing over two small wheels i
respectively of 9 and 16 inches in diameter.
The lowest lifts at Huel Towan and East Crinnis were lift-
ing pumps, and their loads were raised by the working strokes
of their respective engines. All the other pumps were forcing ;
pumps (plungers), and their columns were lifted during the .

return strokes of the engines, by the weight of the rods§.
At Huel Towan, from the surface to a depth of about 534
feet, the connecting rods were 14 inches square; and from

* No correction has been applied for temperature, nor for impurities
contained in the water. At Huel Towan I found, by evaporation, that
about 360 grains were contained in a cubic foot. The temperature is
higher as we descend ; which adds to the already abundant evidence of the
great heat prevailing in the interior of the earth.
+ The stroke in this pump is but 5°5 feet.
t This dift took its supply from the hot-well. ‘
§ The rods are usually very much heavier than the column of water, t
and a counterpoise is applied to balance some part of their weight: such ‘
was the case in all the engines here mentioned.

Mr. Henwood on the Cornish Pumping-Engines. 489

that place downward they extended about 300 feet, and were
12 inches square. They were kept in their places by thirteen
sets of guides, which exposeda surface of about 53°5 square feet*.

From the surface to 396 feet deep in Binner Downs, the
rods were 14 inches square; and from thence downward,
there were about 258 feet of 12 inch rods; these were also
retained by thirteen sets of stays, having an area of about
35°6 feet.

The rods, from the surface to 470 feet deep in East Crinnis,
were 15 inches square, and thence about 200 feet deeper they
were 12 inches: eleven sets of stays retained them in their
places, and exposed a surface of about 38°8 feet.

Where the rods touch the stays they are protected by thin
planks of some hard wood, which are always well covered
with grease; they seldom fit very accurately.

Taste [V.

Duration of the experiments, number of strokes made, materials
consumed, Sc.

Coal 2 ‘
= |s_ |Quantity of} © Ss :
(as 2i| 2G |grease used.| 3 3 /e% 5/2./8 fore
io ee ees BS] 2 /S¢|S218./ Bs
. nor (82/2 [S28 loe ge/ & |ss/ss|'8| 38
arly ieperhnents ye) 2 a5 3h q : qa B, gt Sc ope Se
Engines. periments. | Bal @ |S2le8| 8] 4] 22] s |se/S8| 22] 25
Bele |8slas|a)]a|cs| 4 |55/58/8 | 38
a = ae gc = R aa = AE|A*= = oad
z a & a AS; & FA n _ HE
1831. h.m. Ibs pint.| Ibs. | lbs s s s
22Nov. 232P.m.
5003 ee ly 3 | 7881) 5°35} 16 | 4:8 | 4:8 1847-5
to23Nov. 3 5p.M.
8 Dec. 1059 a.m.
60:5561| =, | 1 | 12:3} 3 {11258) 7-49) 1-34) 4-23) 2-4
to 9Dec. 0 2P.m.
30Nov. 9284.M.
34'5005| 2; | 1 |12 Rear led ee baie

to 1Dec. 755a.M.

The engines were taken without any previous preparation,
and they were worked without intermission, at a speed just
sufficient to keep the mines clear from water; but without
permitting the pumps to draw air (goin fork). The workmen
exercised their own discretion in the mode cf working; for I
purposely abstained from any other interference with them
than was sufficient to satisfy myself that every thing was ex-
posed to my notice, and fairly and honestly performed.

* The lengths of the lifls and of the rods do not coincide, because the
former overlap each other in every case, in order that the higher pumps
may craw out of the same cisterns into which the lower empty ; and be-
cause the rods which take the different /i/ts are also doubled at the sets-off.

Water evaporated
by 100 lbs. of coal.

Cubic
Feet.

16:95

490 Mr. Henwood on the Cornish Pumping-Engines.

The results will appear in

TaBie V.
Weight of the bush-|Duty (in Ibs. lifted one foot high) performed
el of Coal. by eavh bushel of Coal*,
Mines and Engines. As taken
When Bushel 84 Ibs, as taken
pe dry. measured. |from the heap,| °#!bs- dry.
p-
Ibs, Ibs.

Huel Towan, Wilson’s | 100 93°38 | 86,585,079 | 72,687,853 | 77,533,710
Binner Downs, Swan’s | 92°6 83:4 | 73,877,810 | 66,956,572 | 74,395,923
East Crinnis, Hudson’s | 88°53 84:1 | 73,954,606 | 70,003,555 | 73,502,699

Ill.—The work accomplished for a certain expense—The
foregoing details supply all that is requisite for this inquiry,
except the prices of the materials consumed ; these were coal,
at the rate of forty-one shillings for 72 measured bushels + ;
grease, forty-five shillings and sixpence per 112 Ibs.; and oil,
four shillings and twopence per gallon; at which rates the
results were by Huel Towan, Wilson’s engine, 1085 tons;
Binner Downs, Swan’s engine, 1006 tons; East Crinnis,
Hudson’s engine, 870 tons; lifted one foot high for the ex-
pense of one farthing.

As supplementary to the general object of the first part of
this inquiry, it. may be useful to compare the maxima of press~
ures which obtain in the cylinders, with known elasticities in
the boilers; the loads of the engines remaining unchanged.

Taste VI.—Load of engines, and relative pressures of steam
in the boilers and cylinders.

Load on the {Pressure of steam in Ibs. per

Piston, in Ibs. square inch.
Mines and Engines. perisquare. |os7 2 eee
inch of In the Cylin-
its area. |In the Boiler. der}.
Huel Towan, Wilson’st| 10°2 61°8 27
Binner Downs, Swan’s 10°23 Lig mt
Burn’s 10°77 55 30°5
ous ' : 36°8 25
East Crinnis, Hudson’s 114 1563 91
Huel Vor, Trelawny’s 14°7 47 30°5
———_——, Borlase’s 12°1 40 30°5

* These numbers are on the assumption that each pump delivers the
full computed quantity: but in an experiment at Huel Towan, made by
Sir John Rennie and myself, the actual compared with the calculated deli-
very was as 0°924 to unity. I have repeated the comparison at the same
place, with a similar result.

+ The bushel measure with a heaped head is the same which was used
in Mr. Watt’s time, varying only as prescribed by law.

{ The figure in p. 482 refers to this engine.

§ All the pressures mentioned throughout this paper are absolute, and
as if acting against a vacuum.

tee ee

Mr. Henwood on the Cornish Pumping-Engines. 491

Many subjects which are yet undetermined have pressed on
my attention during these experiments, among which the
steam~-case and air-pump are not the least important.

If any condensation take place in the case, when protected
from the influence of the external air, it must be by radiation
to the rarer steam within the cylinder. Now such influence,
if exerted during at least two-thirds of every stroke *, would not
only not increase the force of the engine by adding to the elas-
ticity of the steam, but would render requisite the injection of a
larger quantity of cold water into the condenser to effect con-
densation, and thereby add to the burden of the air-pumpf.

There must be a point at which the resistance of vapour,
not abstracted, to the descent of the piston, and the pressure
of the atmosphere on the air-pump whilst discharging its load,
are ata minimum. Beyond this, if it be attempted to reduce
the force of the vapour, by injecting more cold water, the
burden of the air-pump is increased by the exposure of its
piston to the atmosphere for a longer time during its discharge ;
whilst on the other hand, if it be sought to lessen the duration
of atmospheric pressure on the air-pump, by diminishing the
quantity of cold water introduced into the condenser, the in-
creased elasticity of the unabstracted vapour offers a greater
resistance to the descent of the piston f.

This subject presents many inviting topics of inquiry; but
the pursuit of them, and the earlier preparation of the details §
which I have now the honour to submit to the Institution,
have been prevented by more pressing occupations.

4, Clarence Street, Penzance, W. J. HENWOOD.
August 30th, 1837.

* See Table IV.

+ Brewster’s Edinburgh Journal of Science, O. S. IX., p. 162.

t Ibid., X. p. 40.

y A short notice of these experiments appeared in Brewster’s Edinburgh
Journal of Science, N. S., VI. p. 246.

[ 492 ]
LXXII. Proceedings of Learned Societies.

ROYAL SOCIETY,
[Continued from p. 369. ]

April 11.—A_ paper was read, entitled, ‘‘ On a new equi-atomic
compound of Bicyanide with Binoxide of Mercury.” By James F.
W. Johnston, Esq., F.R.S.

In this paper an account is given of the properties of a salt, ob-
tained by agitating with red oxide of mercury a small proportion of
hydrocyanic acid, and which the author finds to be distinguished
from the bicyanide of mercury by its sparing solubility in cold water,
by the strong alkaline reaction exhibited by its solution, (a property
which indicates an excess of mercury,) and by its susceptibility of
detonation by heat, depending on this excess being in the state of
an oxide, and on the action of the oxygen on a portion of the car-
bon of the cyanogen it contains, and the presence of which is shown
by the disengagement of hydrocyanic acid gas when acted on by
hydrosulphuric and hydrochloric acids.

The analysis of this salt, given by the author, shows it to con-
sist of

CarbUli oat. ss), O720R
Nitrogen ........ 6°025
Oxygen ........ 3°098
NA Sre eons eee Si oe 85°674

100.
The formula of which composition is as follows :
Hg. Cy... + Hg. Ono.

April 18.—The following papers were read, viz.—

«On the Constitution of the Resins.” Part I. By James F. W.
Johnston, Esq., F.R.S.*

The object of the general investigation, of which the commence-
ment is given in this paper, is to determine the relative composition
of the various resins which occur in nature, and to trace the analogies
they exhibit in their constitution ; and also to ascertain how far they
may be regarded as being derived from one common principle, and
whether they admit of being all represented by one or more general
formule.

The chemical investigation of the resin of mastic shows that this
substance consists of two resins; the one soluble, and acid; the
other insoluble, and having no acid properties. ‘The formule ex-
pressing the analysis of each of these are given by the author. He
also shows that a series of analyses may be obtained which do not
indicate the true constitution of a resin. ‘The soluble resin, when
exposed to the prolonged action of a heat exceeding 300° Fahr. is
partly converted into a resin containing three, and partly into one
containing five equivalent parts of oxygen, the proportion of carbon
remaining constant. The same resin combines with bases, so as to

* See our present volume, p. 340.

Royal Society. 493

form four series of salts; which, in the case of oxide of lead, consist
of equivalents of resin and of oxide in the proportions, respectively,
of two to one; three to two; one to one; and one totwo. This
soluble resin in combining with bases does not part with any of its
oxygen; but if any change takes place in its constitution, it consists
in the hydrogen being replaced by an equivalent proportion of a
metal; and formule are given representing the salts of lead on this
theoretical view. By boiling the resin in contact with ammonia and
nitrate of silver, or perhaps with nitrate of ammonia, it is converted
into a resin which forms a bisalt with oxide of silver, in which there
is also an apparent replacement of hydrogen by silver.

The resin next examined is that of dragon’s blood: and the con-
clusions deduced from its analysis are the following. First, that the
lump dragon’s blood is the natural and pure resin, while the strained
and red varieties, being manufactured articles, are more or less de-
composed : secondly, that this resin retains alcohol and ether, as
most other resins do, with considerable tenacity ; but that these sol-
vents may be entirely expelled by a long-continued exposure to a
temperature not higher than 200° Fahr.: and lastly, the formule
representing its chemical composition is given.

“Researches in Embryology.” — Second Series. By Martin
Barry, M.D., F.R.S.E., Fellow of the Royal College of Physicians
in Edinburgh. Communicated by P. M. Roget, M.D. Sec. R.S.*

The author having, in the first series of these researches, investi-
gated the formation of the mammiferous ovum, describes in this
second series its incipient developement. The knowledge at present
supposed to be possessed of the early stages in the developement of
that ovum, consists chiefly of inferences from observations made on
the ovum of the bird.

But there exists a period in the history of the ovum of the mam-
mal, regarding which we have hitherto scarcely any direct or posi-
tive knowledge. It appeared, therefore, highly desirable to obtain
a series of observations in continuous succession on the earliest stages
of developement. In conducting this investigation, the author pur-
posely confined his attention to a single species, namely, the rabbit,
of which he examined more than a hundred individual animals.
Besides ova met with in the ovary, apparently impregnated, and
destined to be discharged from that organ, he has seen upwards of
three hundred ova in the Fallopian tube and uterus ; very few of the
latter exceeding half a line in their diameter. The results of these
investigations have compelled the author to express his dissent from
some of the leading doctrines of embryology, which at present prevail, |
as respects not only the class Mammalia, but the animal kingdom at
large. The following are the principal facts which the author has
observed in the developement of the mammiferous ovum.

The difference between the mature and immature ovum consists
in the condition of the yelk; the yelk of the mature ovum contain-
ing no oil-like globules. Both maceration and incipient absorption

* An abstract of Dr. Barry’s First Series of Researches in Embryology
will be found in L, & E, Phil, Mag., vol, xiii, p, 458,

494 Royal Society.

produce changes in the unimpregnated ovum, which in some respects
resemble those referable to impregnation, During the rut, the num-
ber of Graafian vesicles appearing to become prepared for dischar-
ging their ova, exceeds the number of those which actually discharge
them. Ova of the rabbit which are destined to be developed, are in
most instances discharged from the ovary in the course of nine or ten
hours post coitum; and they are all discharged about the same time.

There is no condition of the ovum uniform in all respects which
can be pointed out as the particular state in which it is discharged
from the ovary; but its condition is in several respects very different
from that of the mature ovum ante coitum, Among the changes
occurring in the ovum before it leaves the ovary, are the follow-
ing: viz. the germinal spot, previously on the inner surface, passes
to the centre of the germinal vesicle; the germinal vesicle, previously
at the surface, returns to the centre of the yelk ; and the membrane
investing the yelk, previously extremely thin, suddenly thickens,
Such changes render it highly probable that the ovary is the usual
seat of impregnation. The author considers this view as being not
incompatible with the doctrine that contact between the seminal
fluid and the ovum is essential to impregnation, since he has found,
in the course of his researches, that spermatozoa penetrate as far as
to the surface of the ovary. ‘The retinacula and tunica granulosa are
the parts acted upon by the vis a tergo, which expels the ovum from
the ovary. These parts are discharged with the ovum, render its
escape gradual, probably facilitate its passage into the Fallopian tube,
and appear to be the bearers of fluid for the immediate imbibition of
the ovum, After the discharge of the ovum from the ovary, the
ovisac is obtainable free from the vascular covering, which, together
with the ovisac, had constituted the Graafian vesicle. It is the
vascular covering of the ovisac which becomes the corpus luteum.
Many ova, both mature and immature, disappear at this time by ab-
sorption, In some animals minute ovisacs are found in the infundi-
bulum, the discharge of which from the ovary appears referable to
the rupture of large Graafian vesicles, in the parietes or neighbour-
hood of which those ovisacs had been situated.

The diameter of the rabbit’s ovum, when it leaves the ovary, does
not generally exceed the 135th part of an inch, and in some in-
stances it is still smaller. ‘The ovum enters the uterus in a state
very different from that in which it leaves the ovary; hence the
opinion, that ‘‘in their passage through the tube the ova of Mam-
malia undergo scarcely any metamorphosis at all,” is erroneous.
Among the changes taking place in the ovum during its passage
through the Fallopian tube are the following; viz, 1. An outer
membrane, the chorion, becomes visible. 2. The membrane origin-
ally investing the yelk, which had suddenly thickened, disappears
by liquefaction ; so that the yelk is now immediately surrounded by
the thick transparent membrane of the ovarian ovum. 3. In the
centre of the yelk, that is, in the situation to which the germinal
vesicle returned before the ovum left the ovary, there arise several
very large and exceedingly transparent vesicles; these disappear,

Royal Society. 495

and are succeeded by a smaller and more numerous set ; several sets
thus successively come into view, the vesicles of each succeeding set
being smaller than the last, until a mulberry-like structure has been
produced, which occupies the centre of the ovum. Each of the ve-
sicles of which the surface of the mulberry-like structure is com-
posed contains a pellucid nucleus; and each nucleus presents a nu-
cleolus.

In the uterus a layer of vesicles of the same kind as those of the
last and smallest set here mentioned makes its appearance on the whole
of the inner surface of the membrane which now invests the yelk. The
mulberry-like structure then passes from the centre of the yelk to a
certain part of that layer, (the vesicles of the latter coalescing with
those of the former where the two sets are in contact to form a
membrane, ) and the interior of the mulberry-like structure is now
seen to be occupied by a large vesicle containing a fluid and gra-
nules. In the centre of this vesicle is a spherical body having a
granulous appearance, and containing a cavity apparently filled with
a colourless and pellucid fluid. This hollow spherical body seems
to be the true germ. The vesicle containing it disappears, and in
its place is seen an elliptical depression filled with a pellucid fluid.
In the centre of this depression is the germ, still presenting the ap-
pearance of a hollow sphere. ‘The germ separates into a central and
a peripheral portion, the central portion occupies the situation of the
future brain, and soon presents a pointed process which is the rudi-
ment of the spinal cord. ‘These parts at first appearing granulous
are subsequently found to consist of vesicles.

Thus the central portion of the nervous system is not originally
a fluid contained within a tube, but developes itself in a solid
form before any other part. The central portion of the nervous
system sometimes attains a considerable degree of developement,
although it be exceedingly minute; thus an instance has been met
with in which the developement of this part had reached a stage
scarcely inferior to that in another instance, in which the corre-
sponding part measured more than ten times the length.

There does not occur in the mammiferous ovum any such pheno-
menon as the “splitting ’”’ of a membrane into the so-called ‘ se-
rous, vascular, and mucous laminew.’”’ Rathke had already found
that parts previously supposed by Baer and others to be formed by
the so-called “ germinal membrane,” really originate independently
of it; these parts are the ribs, pelvic bones, and the muscles of the
thorax and abdomen, which according to Rathke arise in a part pro-
ceeding out of the “‘ primitive trace” itself. Reichert had previously
discovered that the part originating the lower jaw and hyoid bone
“ grows out of the primitive trace.” The author beginning with an
earlier period goes farther than these observers, and shows that
the so-called “ primitive trace”’ itself does not arise in the substance
of a membrane, but presents a comparatively advanced stage of the
object above described as the true germ. Hence the author suggests,
there is no structure entitled to be denominated the “ germinal
membrane,”

496 Royal Society.

The most important of the foregoing facts respecting the deve-
lopement of the mammiferous ovum, however opposed they may be
to received opinions, are in accordance with, and may even explain,
many observations which have been made on the developement of
other animals as recorded in the delineations of preceding observers.
If in the ovum of the bird the germinal vesicle in like manner re-
turns to the centre of the yelk, the canal and cavity known to exist
in the yelk of that ovum might be thus explained. The ovum may
pass through at least one-and-twenty stages of developement, and
contain, besides the embryo, four membranes, one of which has two
lamine, before it has itself attained the diameter of half a line, a fifth
membrane having disappeared by liquefaction within the ovum.

The size of the minute ovum in the Fallopian tube and uterus
affords no criterion of the degree of its developement; nor do any
two parts of the minute ovum, in their developement, necessarily
keep pace with one another.

The proportion of ova met with in these researches, which seemed
to be abortive, has amounted to nearly one in eight. Sometimes
two yelk-balls exist in the same ovam. With slight pressure, the
ovum, originally globular, becomes elliptical. Its tendency to as-
sume the latter form exists especially in the chorion, and seems to
be in proportion to its size.

The author has discovered that when the germinal vesicle is first
seen it is closely invested by an extremely delicate membrane. This
membrane subsequently expanding is that in which the yelk is
formed. He has traced the chorion from stage to stage up to the
period when it becomes villous, and shows that it is not, as he for-
merly supposed, the thick transparent membrane itself of the ovarian
ovum, but a thin envelope closely investing that membrane, and not
appreciable as a distinct structure until the ovum has been crushed.
When the chorion first admits of demonstration as a distinct struc-
ture the ovum consists of three membranes, a state which the author
has seen in an ovum no farther advanced than about an inch into the
Fallopian tube. ‘The chorion subsequently thickens and imbibes a
quantity of fluid presenting a gelatinous appearance.

April 25.—A paper was in part read, entitled, “ Account of Experi-
ments on Iron-built Ships, instituted for the purpose of discovering
a Correction for the Deviation of the Compass produced by the Iron
of Ships.” By George Biddell Airy, Esq., M.A., F.R.S., A.R.

May 2.—A paper was in part read, entitled, “On the Motion of
the Blood.” By James Carson, M.D., F.R.S.

May 9.—The reading of a paper, entitled, ‘‘ On the Motion of the
Blood.’”’By James Carson, M.D., F.R.S., was resumed and concluded.

After referring to his paper contained in the Philosophical Trans-
actions for 1820, relative to the influence of the elasticity of the
lungs as a power contributing to the effectual expansion of the heart,
end promoting the motion of the blood in the veins, the author states
that his object in this paper is to explain more fully the mode in
which these effects are produced, and to corroborate by additional
facts and observations the arguments adduced in its support, He

¥

Royal Society. 497

endeavours, from a review of the circumstances under which the veins
are placed, to show the inconclusiveness of the objections which
have been urged by various physiologists against his and the late
Sir David Barry’s theory of suction ; namely, that the sides of a
pliant vessel, when a force of suction is applied, will collapse and
arrest the further transmission of fluid through that channel. The
considerations which he deems adequate to give efficacy to the
power of suction in the veins of a living animal are, first, the posi-
tion of the veins by which, though pliant vessels, they acquire in
some degree the properties of rigid tubes; secondly, the immersion
of the venous blood in a medium of a specific gravity at least equal
to its own; thirdly, the constant introduction of recrementitious
matter into the venous system at its capillary extremities by which
the volume of the venous blood is increased, and its motion urged
onwards to the heart in distended vessels; and lastly, the gravity
of the fluid itself, creating an outward pressure at all parts of the
veins below the highest level of the venous system. ‘The author il-
lustrates his positions by the different quantities of blood which
are found to flow from the divided vessels of an ox, according to the
different modes in which the animal is slaughtered.

The reading of a paper, entitled, ‘‘ Account of Experiments on
Iron-built Ships, instituted for the purpose of discovering a Correc-
tion for the Deviation of the Compass produced by the Iron of the
Ships.” By George Biddell Airy, Esq., A.M., F.R.S., Astronomer
Royal, was also resumed and concluded.

In this paper the problem of the deviation of a ship’s compass,
arising from the influence of the iron in the ship, more particularly
in iron-built ships, is fully investigated ; and the principles on which
the correction for this deviation depends having been determined,
practical methods for neutralizing the deviating forces are deduced
and illustrated by experimental application. The author states that,
for the purpose of ascertaining the laws of the deviation of the com-
pass in the iron-built steam-ship the Rainbow, four stations were
selected in that vessel, about four feet above the deck, and at these
the deviations of the horizontal compasses were determined in the
various positions of the ship’s head. All these stations were in the
vertical plane, passing through the ship’s keel, three being in the
after part of the ship and one near the bow. Observations were also
made for determining the horizontal intensity at each of the stations.
The deviations of dipping needles at three of these stations were
also determined, when the plane of vibration coincided with that of
the ship’s keel, and also when at right angles to it.

After describing the particular method of observing rendered ne-
cessary by the nature of the vessel and the circumstances of her
position, the author gives the disturbance of the horizontal compass
at the four stations deduced from the observations. ‘he most
striking features in these results are, the very great apparent change
in the direction of the ship’s head, as indicated by the compass nearest
the stern, corresponding to a small real change in one particular
position, the former change being 97°, whereas the latter was only

Phil, Mag. 8. 3. Vol. 14, No, 92. Suppl. July, 1889, 2 Kk

498 Royal Society.

23°, and the small amount of disturbance indicated by the compass
near the bow.

After giying the observations for the determination of the influ-
ence of the ship on the horizontal intensity of a needle suspended
at each of the stations, in four different positions of the ship’s head,
and the disturbances of the dipping needle at three of these stations,
the author enters upon the theoretical investigation.

The fundamental supposition of the theory of induced magnetism,
on which Mr. Airy states his calculations to rest, is, that, by the ac-
tion of terrestrial magnetism, every particle of iron is converted into
a magnet, whose direction is parallel to that of the dipping needle,
and whose intensity is proportional to that of terrestrial magnetism,
the upper end haying the property of attracting the north end of
the needle, and the lower end that of repelling it.

The attractive and repulsive forces of a particle on the north end
of the needle, in the directions of rectangular axes towards north,
towards east, and vertically downwards, and of which the compass
is taken as the origin, are first determined on this supposition in
terms of the co-ordinates; and thence the true disturbing forces of
the particle in these directions. The disturbing forces produced by
the whole of the iron of the ship are the sums of the expressions for
every particle, Expressing this summation by the letter S, and
transforming the rectangular into polar co-ordinates, Mr. Airy gives
to the expressions for the disturbing forces the simplifications which
they admit of, on the supposition that the compass is in the vertical
plane passing through the ship’s keel, and that the iron is symme-
trically disposed on both sides of that plane. He thus deduces for
the disturbing forces acting on the north or marked end of the
needle,

—Icos 6. M +I cos 6. P cos2 A + Isind. N cos A, towards the
magnetic north ;

Icos 6. Psin2 A + Isind. N sin A, towards magnetic east ;

— Isind. Q + Icosé.N cos A, vertically downwards :

Where I represents the intensity of terrestrial magnetism; 0 the
dip; A the azimuth of the ship’s head; and M,N, P, Q, constants
depending solely on the construction of the ship, and not changing
with any variations of terrestrial localities or magnetic dip or inten-
sity.

From the consideration of these expressions for the disturbing
forces is deduced the following simple rule for the correction of a
compass disturbed by the induced magnetism only of the iron in a
ship.

1. Determine the position of Barlow’s plate with regard to the
compass, which will produce the same effect as the iron in the
ship.

D. Fix Barlow’s plate at the distance and depression determined
by the last experiment, but in the opposite azimuth.

3. Mount another mass of iron at the same level as the compass,
but on the starboard or larboard side, and determine its position so
that the compass points correctly when the ship’s head is N.E,, 8.E.,

Royal Society, 499

S.W. or N.W.; then the compass will be correct in all positions of
the ship’s head, and in all magnetic latitudes.

When the disturbing iron of the ship is at the same level as the
compass, the correction is stated to be much more simple, it being
then only necessary to introduce a single mass of iron at the star-
board or larboard side, and at the same level as the compass.

It is farther remarked that if one mass of iron is placed exactly
opposite another equal mass, both in azimuth and in elevation, it
doubles its disturbing effect: if one mass be placed opposite the
other in azimuth, but with elevation instead of depression, or vice
versd, it destroys that term of the disturbance which depends on sin
A, and doubles that which depends on sia 2A: and if one mass
be placed at the same level as the compass, its effects may be de-
stroyed by placing another mass at the same level, in an azimuth
differing 90° on either side. Ifa disturbance, from whatever cause
arising, follow the law of + sin 2 A, (changing sign in the success-
ive quadrants, and positive when the ship’s head is between N. and
E.), it may be destroyed by placing a mass of iron on the starboard
or larboard side at the same level as the compass; if it follow the
law of — sin 2 A, the mass of iron must be on the fore or aft
side.

From the consideration of the expression for the disturbing forces
produced by the ship, it is farther inferred, that both in the con-
struction of the ship and in the fixing of correctors, no large mass of
iron should be placed below the compass.

The expressions for the disturbing forces towards north and east,
being transformed into forces towards the ship's head and towards
the starboard side, give

Icos 8, (— M + P) cos A + Isind.N, for the former, and

Icos 6.(M + P), for the latter.

The author next proceeds to investigate the effects which result
from the combination of induced magnetism with permanent mag-
netism, Calling H, S and V the new forces arising from the latter,
and directed towards the ship’s head, its starboard side, and verti-
eally downwards, the whole disturbing force towards the ship’s
head becomes

H + Icosd.(—M + P)cosA + Isind.N;
and the whole disturbing force towards the starboard side,
S + I1cosd.(M+ P)sinA.

The manner in which the numerical values of these quantities may
be found from experiment is then pointed out, and being determined
from the observations on board the Rainbow, at Station I., a compa-
rison is made between the observed disturbances of the needles, and
those which would result from the action of the ship as a permanent
magnet. From this comparison it appears that almost the whole
disturbance is accounted for by the permanent magnetism, and that
the residual part follows with sufficient approximation the law of
changing signs at the successive quadrants. For the complete veri-
fication of the theory it remained only to effect an actual correction
of the compass. ‘This was done by placing below the compass, in a

2K2

500 Royal Society.

position determined by the previously-ascertained numerical values,
a large bar magnet to neutralize the effects of the permanent mag-
netism of the ship, and a roll of soft iron on one side of the compass
to counteract the disturbance arising from induced magnetism. ‘That
this correction was effective appears from the very small amount of
uncorrected disturbance then observed in the compass.

The observations of the compasses at stations II., III., IV., are
similarly discussed: the disturbing force arising from the permanent
magnetism of the ship being in like manner determined, a comparison
is instituted between the observed and computed disturbance of the
compass ; and the results of this comparison, with the exception of
the observations at Station IV., are found to be in perfect accordance
with the theory. Attempts are made to correct the compasses at
these stations in the same manner as at Station I., but owing to the
imperfection of the compasses they did not succeed so perfectly.

The observations made with the dipping needle are next discussed,
and the values of the constants are deduced from them. ‘The gene-
ral agreement of those determined from the observations when the
needle vibrated in the direction of the ship’s keel, with those de-
duced from the observations when the needle vibrated transversely,
is pointed out, and is considered an additional proof of the general
correctness of the theory.

Observations on the disturbance of the compass in the iron-built
sailing-ship Ironsides are next described. ‘These are similar to
those in the Rainbow, but not so extensive ; and they are discussed
on the same principles. From this discussion it is considered that
the theory is in perfect accordance with the facts observed both with
regard to the deviations and the intensities. The correction of one
compass was effected by a tentative process, which the author consi-
ders likely to be of the highest value in the correction of the compasses
of iron-ships in general. The ship’s head being placed exactly north,
as ascertained by a shore compass, a magnet was placed upon the
beam from which the compass was suspended, with the direction of
its length exactly transverse to the ship’s keel: it was moved upon
the beam to various distances till the compass pointed correctly, and
then it was fixed. Then the ship’s head was placed exactly east,
and another magnet, with its length parallel to the ship’s keel, was
placed upon the same beam, and moved to different distances till
the compass pointed correctly, and then it was fixed. The correc-
tion for induced magnetism was neglected, but there would have
been no difficulty in adjusting it by the same process, placing the
vessel’s head in azimuth 45° or 135° or 225° or 315°.

In conclusion Mr. Airy makes the following remarks :—

The deviations of the compass at four stations in the Rainbow,
and at two stations in the Jronsides, are caused by two modifications
of magnetic power; the one being the independent magnetism of
the ship, which retains, in all positions of the ship, the same mag-
nitude and the same direction relatively to the ship; the other being
the induced magnetism, of which the force varies in magnitude and
direction when the ship’s position is changed, In the instances

Royal Society. 501

mentioned, the effect of the former force was found greatly to exceed
that of the latter.

It appears that experiments and observations similar to those
applied in the above cases are sufficient to obtain with accuracy the
constants on which at any one place the ship’s action on the hori-
zontal needle depends, namely,
ical 3p + tand.N, ooo —— M, andP;
and that by enn a magnet so that its action shall take place in a
direction opposite to that which the investigations show to be the
direction of the ship’s independent magnetic action, and at such a
distance that its effect is equal to that of the ship’s independent
magnetism, and by counteracting the effect of the induced mag-
netism by means of the induced magnetism of another mass, accord-
ing to rules which are given, the compass may be made to point
exactly as if it were free from disturbance.

It appears also, that by an easy tentative method, the compass
may now be corrected without the labour of any numerical investi-
gations or any experiments except those of merely making the
trials. Although the uniformity of the induced magnetism under
similar circumstances is to be presumed, yet the invariability of the
independent magnetism during the course of many years is by no
means certain.

These statements suggest the following as rules which it is desi-
rable to observe in the present infancy of iron-ship building. It
appears desirable that

1. Every iron sea-going ship should be examined by a competent
person for the accurate determination of the four constants above-
mentioned for each of the compasses of the ship, and a careful ‘re-
cord of these determinations should be preserved as a magnetic
register of the ship.

2. The same person should be employed to examine the vessel at
different times, with the view of ascertaining whether either of the
constants changes in the course of time.

3. In the case of vessels going to different magnetic latitudes,
the same person should make arrangements for the examination of
the compasses in other places with a view to the determination of
the constant N.

4. The same person should examine and register the general
construction of the ship, the position and circumstances of her build-
ing, &c., with a view to ascertain how far the values of the magnetic
constants depend on these circumstances, and in particular to ascer-
tain their connexion with the value of the prejudicial constant M.

5. The same person should see to the proper application of the
correctors and the proper measures for preserving the permanency
of their magnetism.

The most remarkable result in a scientific view from the experi-
ments detailed in the present paper is, the great intensity of the per-
manent magnetism of the malleable iron of which the ship is com-
posed.

502 Geological Society :~Anniversary of 1839.

May 16.—A_ paper was read, entitled ‘‘ On the visibility of cer-
tain rays beyond the ordinary red rays of the Solar Spectrum.” By
J.S. Cooper, Esq., in a letter to Michael Faraday, Esq., D.C.L.,
F.R.S., &c., &e. Communicated by Dr. Faraday.

The author states his having observed an extension of the red por-
tion of the solar spectrum, obtained in the ordinary way, beyond
the space it occupies when seen by the naked eye, by viewing it
through a piece of deep blue cobalt glass. He finds that the part of
the spectrum thus rendered perceptible to the right is crossed by
two or more very broad lines or bands; and observes that the space
occupied by the most powerful calorific rays, coincides with the si-
tuation of the red rays thus rendered visible by transmission through
a blue medium. ‘The author expresses a regret that he has not had
sufficient leisure to pursue the investigation of these phenomena.

A paper was also in part read, entitled, ‘‘ Fifth letter on Voltaic
Combinations, with some account of the effects of a large constant
Battery :”’ addressed to Michael Faraday, Esq., D.C.L., F.R.S., &c.
By John F. Daniell, Esq., F.R.S.

The Society then adjourned over the Whitsun Recess, to meet
again on the 30th of May.

GEOLOGICAL SOCIETY.
President’s Anniversary Address, Feb. 15: continued from p. 461.

GEOLOGICAL DYNAMICS.

In that part of geology which I have termed Geological Dynamics,
and which investigates and applies those causes of change by which
we may hope to explain geological phenomena, we may still observe
that fundamental antithesis of opinion which has long existed on the
subject ;—the division of our geological speculators into Catastro-
phists and Uniformitarians ;—into those who read in the rocks of the
globe the evidence of vast revolutions, of an order different from
any which those of man has survived ;—and those who see in the con-
dition of the earth the result of a series of changes which are still
going on without decay, the same powers which produced the ex-
isting valleys and mountains being yet at work about us. Both these
opinions have received their contributions during the preceding
year: Mr. Darwin having laid before us his views of the formation
of mountain chains and volcanos, which he conceives to be the effect
of a gradual, small, and occasional elevation of continental masses
of the earth’s crust*; while Mr. Murchison gathers from the re-
searches in which he has been engaged, the belief of a former state
of paroxysmal turbulence, of much deeper rooted intensity and wider
range than any that are to be found in our own period; and M. de
Beaumont, in France, has endeavoured to prove that Etna and many
other mountains must have been produced by some gigantic and ex-
traordinary convulsion of the earth. Both Mr. Darwin and M. de

* An abstract of Mr. Darwin’s paper was given in L. & E. Phil. Mag.,
vol. xii. p. 584.

=

Geological Society. 508

Beaumont refer to the same examples; and while M. de Beaumont
conceives that the cones of the Andes must have been formed by an
abrupt elevation, caused by subterranean force, Mr. Darwin has
maintained the opinion, that these lofty summits have been gra-
dually thrust into the place which they occupy by a series of suc-
cessive injections of molten matter from below, each intruded por-
tion of fluid having time to harden into rock before it was burst
and again injected by the next molten mass. For how otherwise,
he asks, can we conceive the strata to be thrust into a vertical po-
sition by a liquid from below, without the very bowels of the earth
gushing out? Without attempting to answer this question, we may
observe, that when we suppose, as Mr. Darwin supposes, a vast por-
tion of the earth’s crust, the whole territory of Chili for example,
to rest on a lake of molten stone, there is considerable force in M.
de Beaumont’s argument :—that when such a fluid is raised to the
top of a mountain ten or twenty thousand feet high, the pressure
upon the crust which is in contact with the fluid must be more than
a thousand atmospheres ; and who, he too asks, flatters himself that
he knows enough of the interior machinery of volcanos, to be cer-
tain that this vast pressure, acting upon a large surface, may not, by
some derangement of its safety-valve, the volcanic vent, produce
effects to which we cannot assign any limit ?

In speaking of Mr. Darwin’s researches I cannot refrain from ex-
pressing for myself, and I am sure I may add for you, our disap-
pointment and regret that the publication of Mr. Darwin’s journal
has not yet taken place. Knowing, as we do, that this journal con-
tains many valuable contributions to science, we cannot help lament+
ing, that the customs of the Service by which the survey was con-
ducted have not yet allowed this portion of the account of its results
to be given to the world.

Although not communicated to us, but to our Alma Mater the
Royal Society, I may notice Mr. Hopkins’s endeavours to throw
light upon such subjects as this by the aid of mathematical reason-
ing. The researches of Mr. Hopkins respecting the effects which a
force from below would produce upon a portion of the earth’s crust,
have already interested you, and would be of still greater value if
the directions of faults and fissures which result from his theory did
not depend very much upon that which in most cases we cannot ex-
pect to know, the form of the area subjected to such strain. Mr.
Hopkins has since been employing himself in tracing the conse-
quences of another idea, truly ingenious and philosophical, and which
a person in full possession of the resources of mathematics could
alone deal with. Some of the effects which the sun and moon pro-
duce upon the earth (as the precession and nutation,) include the
attraction of those bodies upon the interior portion of the earth, and
have hitherto been deduced from the theory by mathematicians,
upon the supposition that the earth is solid. But what if the central
portion of the earth were fluid? What ifit appeared, by calculation,
that the fluid internal condition would make the amount of the pre-
cession of the equinoxes, or of the nutation of the axis, different

504 Geological Society :— Anniversary of 1839.

from that which the solid spheroid would give? What if it ap-
peared that the precession and nutation thus calculated for a fluid
interior agreed better with observation than the result hitherto ob-
tained by supposing the earth solid? Ifthis were so, we should
have evidence of the earth’s interior fluidity, evidence, too, of a per-
fectly novel and most striking nature. But to answer these ques-
tions is far from an easy task ; the precession of the solid earth is a
problem in which Newton erred, and in which the greatest mathe-
maticians of modern times have not found their greatest strength
superfluous. Yet how incomparably more difficult in all cases is the
mechanics of fluid than of solid bodies! It may, therefore, require
more than one trial before any satisfactory solution of the problem
can be obtained. Mr. Hopkins has attacked it by the aid of cer-
tain hypotheses, and the result is, so far, not favourable to the de-
cisiveness of this test of the interior condition of the earth; but not-
withstanding this state of things, I venture to say on your behalf,
Gentlemen, that an idea so full of promise of that which we so
much desire, and which seems to be so utterly out of our reach,
the knowledge of the condition of the centre of the earth,—that
such an idea is not to be lightly abandoned*.

M. Necker, of Geneva, offered an addition to the causes of con-
vulsions of the earth, which are contemplated by our Geological
Dynamics, in a paper in which he ascribed the earthquakes which
took place in the southern provinces of Spain, in 1829, to the falling in
of strata, the subjacent gypseous and saliferous masses being washed
out by subterraneous currentst. Without denying allinfluence to
such a cause, we may observe that it does not appear likely that

* The following are the results at which Mr. Hopkins has arrived, sup-
posing the earth to consist of a homogeneous spheroidal shell filled with
a fluid mass of the same density as the shel] :—

1. The precession will be the same, whatever be the thickness of the
shell, as if the whole earth were solid.

2. The lunar nutation will be the same as for the solid spheroid, to such
a degree of approximation, that the difference would be inappreciable to ob-
servation.

3. The solar nutation will be sensibly the same as for the solid spheroid;
unless the thickness of the shell be very nearly of a certain value, some-
thing less than one fourth the earth’s radius, in which case this nutation
might become much greater than for the solid spheroid.

4. In addition to the above motions of precession and nutation, the pole
of the earth would have a small circular motion, depending entirely on the
internal fluidity. The radius of the circle thus described would be the
greatest when the thickness of the shell should be least ; but the inequality
thus produced would not, for the smallest thickness of the shell, ex-
ceed a quantity of the same order as the solar nutation; and for any but
the most inconsiderable thickness of the shell, would be entirely inappre-
ciable to observation.

Mr. Hopkins intends hereafter to consider the case of variable density.

(See our present volume, p. 864.—Ebir. |

[+ An abstract of M. Necker’s paper has appeared in the present volume,
p. 370.—Epir. }

Geological Society. 505

there would be thus produced, simultaneously, any greater effects
than those which are known to have occurred from the falling in
of unsupported mines; and these have never approached in their
scale to any except the smallest earthquakes.

While geologists are thus looking in all directions for causes which
may produce the phenomena which they study, it is natural that the
powerful, but as yet mysterious influences of electricity should draw
their attention. Mr. Robert Were Fox has endeavoured to show,
that by voltaic agency, a laminated structure, and deposits of metal
in cracks, resembling metallic veins, may be produced in masses of
clay. The experiments are of an interesting kind, and it can hardly
be doubted that voltaic agency had some influence in such cases
as those described by Mr. Fox; although Mr. Henwood and Mr. Stur-
geon have failed in attempting to reproduce his results, and although
results much resembling these occur in cases where no electrical ac-
tion is suspected. But we may remark that the conditions under
which such voltaic effects are produced have not yet been attempted
to be defined with any accuracy ; and that till this is done, the reality
of such agency can neither be verified nor applied to geological
speculations.

A reflection which naturally offers itself upon this review of our
recent career, is this :—that different portions of the science of geo-
logy advance with very different rapidity. Descriptive Geology is con-
stantly and actively progressive: facts are accumulated by observers
in every land; and though facts are, in truth, of no value, at least
for any purpose of science, except so far as they are reduced to some
classification, yet on the other hand, sound classifications are perpe-
tually, almost necessarily, suggested, when observation is vigilant
and persevering. Even if we at first express our facts in terms of a
false classification, we find afterwards the means of translating them
into the language of a true one. And the spirit of geological ob-
servation is so widely diffused, and so thoroughly roused, that I
trust we need not anticipate any pause or retardation in the career
of Descriptive Geology. I confess, indeed, for my own part, I do
not look to see the exertions of the present race of geologists sur-
passed by any who may succeed them. ‘The great geological theo-
rizers of the past belong to the Fabulous Period of the science ; but
I consider the eminent men by whom I am surrounded as the Heroic
Age of geology. ‘They have slain its monsters, and cleared its wil-
dernesses, and founded here and there a great metropolis, the queen
of future empires. They have exerted combinations of talents which
we cannot hope to see often again exhibited, especially when the
condition of the science which produced them is changed. I consider
that it is now the destiny of geology to pass from the heroic to the
Historical Period. She can no longer look for supernatural suc-
cesses, but she is entering upon a career, J trust a long and prosper-
ous one, in which she must carry her vigilance into every province
of her territory, and extend her dominion over the earth, till it
becomes, far more truly than any before, an universal empire.

506 Geological Society :—-Anniversary of 1839.

Such are the prospects of Descriptive Geology ;—of the geolog
of facts and classifications. To our knowledge of causes we can iaak
with no such certainty of its progress being steady and rapid; or
rather, we are certain that the advance must be slow, and may be
often and long interrupted. For it is not an advance, to suggest one
or another hypothetical cause of change, without assigning the laws
and amount of the change: it is hardly an advance even to calculate
the results of our hypotheses on assumed conditions. To obtain by
induction, from adequate facts, the laws of change of the organic
and inorganic creation,—this alone can lead us to those discoveries
which must form the epochs of Geological Dynamics. And we have
yet to learn, whether man’s past duration upon the earth, whether
even that which is still destined to him, is such as to allow him to
philosophize with success in such matters ;—whether, not individuals
only, not a generation alone, but whether the whole species be not
too ephemeral, to penetrate, by the unassisted powers of its reason,
into the mystery of its origin :—whether man, placed for a few cen-
turies on the earth as in a school-room, have time to strip the wall
of its coating, and count its stones, before his Parent removes him
to some other destination.

And now, Gentlemen, I approach the close of my task, and of the
office which has imposed it upon me; an office which has been to
me a source of unmingled gratification. The good opinion implied
by your selection of me, the good opinion of such a body of men,
was an occasion of sincere and earnest self-congratulation,—a self-
congratulation hardly damped by my consciousness of an imperfect
acquaintance with your science ;—since I trusted that you, though
not unaware of my defects, had judged that good will, and a dispo-
sition to look at the subject in its largest aspect, might in some
measure compensate for them. And if I needed other grounds of
satisfaction in the employment which I am thus bringing to its close,
I might find them in the reflections I have just been led to make in
the progress and prospects of the science with which you are con-
cerned. For it has ever been one of my most cherished occupations,
and will, I trust, long be so, to trace the principles and laws by which
the progress of human knowledge is regulated from age to age in
each of its provinces. To have had brought familiarly under my
notice, in a living form, the daily advance of a science so large and
varied as yours, has been, as it could not but be, a permanent
and most instructive lesson ;—perpetually correcting lurking mis-
takes, and suggesting new thoughts. And if, while I have looked
at your science in this spirit, you have thought me worthy to be
called to preside over your body for two years; and if, during that
time, you have not repented of your choice, as I have not found
my views inapplicable to the subjects which have come before you;
I may, I would believe, find in this some ground for confiding in
the trains of thought which have thus led me to such a position ;
and may hope that, however arduous be the task of framing a philo-
sophy of science suitable to its present condition, and of using such
a philosophy as a means of furthering knowledge in general, still,

Geological Society. 507

that in this task, to which our age is so manifestly called, [ too
may be a helper.

I trust that you will excuse these few words uttered with reference
to my own peculiar pursuits, since these include yours also, and are
my only claim to your indulgence. And now, Gentlemen, that I
may trespass upon that indulgence no longer, I once more thank
you in all earnestness and sincerity for your good opinion which
placed me in this chair, and for the kindness and support which I
have on all occasions received from you; and with my best wishes
for your prosperity, and that of your science, I resign my office into
abler hands.

Feb. 27.—A paper was first read, entitled “‘ An Account of Im-
pressions and Casts of Drops of Rain, discovered in the Quarries at
Storeton Hill, Cheshire,” by John Cunningham, Esq., F.G.S.

The author commences by stating, that no person acquainted with
Geology, can doubt of rain having fallen during remote ages of the
world, because to its destructive and transporting powers many of
the sedimentary strata must have owed their origin. He also ob-
serves, that the vast forests which flourished anterior to the era of
the new red sandstone, and are now treasured up in beds of coal,
could not have existed without abundant supplies of atmospheric
waters. Mr. Cunningham refers likewise to Mr. Scrope’s account
of the permanent preservation of the effects of a shower, which fell
on extremely fine ashes, thrown out by Vesuvius during the eruption
of 1822. The drops of rain formed globules which resembled in shape
and motion those produced by sprinkling water on a dusty floor; and
the globules afterwards hardened into pellets, which accumulated,
at the bottom of a slope in some places, into beds a foot or more
thick ; and they afterwards became so firmly agglutinated, that it re-
quired a smart blow from a hammer to break the mass.

The effects of rain described by Mr. Cunningham, are, however,
of a kind entirely different from those produced on the ashes of
Vesuvius. They were discovered by him in the sandstone quarries
in which the footsteps of the Chirotherium were found*; and he
was the first to assign their origin to the effects of rain. ‘The
under surface of two strata, at the depth of 32 and 35 feet from
the top of the quarry, present a remarkably blistered or warty
appearance, being densely covered by minute hemispheres of the
same substance as the sandstone. ‘hese projections are casts in
relief of indentations in the upper surface of a thin subjacent bed
of clay, and due, in the author’s opinion, to drops of rain. On
one of the layers of clay, they are small and circular, as if pro-
duced by a gentle shower; on the other, they are larger, deeper
and less regular in form, indicating a more violent operation,
possibly accompanied by hail. On the surface of these layers of
clay there are also impressions of the feet of small animals, which
appear to have passed over the clay either during the showers or not

* See the Memoir by the Committee of the Natural History Society of
Liverpool, p. 12,

508 Geological Society.

long before, as the footsteps are indented by the drops of rain, but
to a less degree than the untrodden parts, in consequence, the author
conceives, of the pressure which the clay had undergone beneath the
feet of the animals. Ripple marks are exhibited also on the surface of
many sandstone strata in the same quarries; and the rain marks as
well as the sharpness of many of the footsteps prove, that the clay was
not covered by water during the shower, or while traversed by the
animals; and Mr. Cunningham, therefore, is of opinion that the con-
ditions necessary to the preservation of such impressions, particu-
larly of the rain drops, would be a return of water over surfaces
which had been left uncovered during an interval too short for the
desiccation of the Jamine of clay before the shower fell; and which
were sufficiently soft to receive the impressions, as well as tenacious
enough to retain them, until the return of the water which filled the
prints with sand. Another condition is, that the velocity of the
water charged with the sand was not sufficient to overcome the
tenacity of the clay, or disturb the impressions of the rain drops. The
author adds, that Dr. Buckland has suggested to him, that the interval
between the rise and fall of tides over extensive sandbanks, the sur-
face of which was between the level of high and low water, might
have afforded daily occasions for the fulfilment of all the conditions ;
and that it is not easy to explain the alternate exposure to air and
submersion under water without appealing to the flux and reflux of
tides.

An extract was then read from a letter addressed to Dr. Buckland,
by John Taylor, jun., Esq., F.G.S., on a slab of sandstone, exhibit-
ing footmarks, and supposed to be from the Kelsall quarry, at the
foot of Delamere Forest, but now in a pavement in the house of Mr.
Potts, of Chester.

A letter was next read, addressed to Dr. Buckland by Sir Philip
Grey Egerton, Bart., M.P., F.G.S., respecting the same slab ; and
accompanied by a tracing of the foot-marks, by Miss Potts.

When the slab was first laid down, there were no indications of the
footsteps, and Sir Philip Egerton explains, in the following manner,
their origin in a homugeneous stone and subsequent development.
The weight of the animal on the soft sand compressed the yielding
materials in the vicinity of the foot, and the print having been
filled with sand, the stone, on becoming indurated, would present a
nearly uniform texture. The action of the weather, on the flag
being exposed, would remove the softer portions of the surface, and
the denser parts surrounding the impressions of the feet, would resist
the same operation, and present in relief the outline of the foot.

The flag contains the prints of three hind and two fore feet, the
latter bearing nearly the same proportions to the former as in the
other species, but Sir Philip Egerton could not make accurate
measurements, because the markings are not all on one plane; the
length of the stride he was also unable to determine, in consequence
of the impressions in the same line being all of the right foot. There
are distinct marks of claws on several of the toes.

A paper was next read, ‘‘ On the occurrence of numerous Swallow

Geological Society. 509

Holes, near Farnham ; with some observations on the drainage of the
country at the western extremity of the Hog’s Back,’ by Henry
Lawes Long, Esq., and communicated by C. Lyell, Esq., V.P.G.S.

Farnham stands at the foot of the chalk hills, upon a deep bed of
loam, which appears to overlie the gault. Upon the chalk, imme-
diately to the north of the town, is the castle, beyond which the
tertiary strata commence and rise to a considerable height, forming
the great mass of hill known by the name of Farnham Beacon, Tun-
bury, or the Lawday House. On the north side, this hill presents,
for the greater part, an abrupt precipice, under which several streams
are thrown out; but on the south there are landsprings only, which
occupy the gullies for the greater portion of the year, and occasion-
ally become formidable torrents. ‘These rivulets pour down the
tertiary clays until they arrive at the chalk, where they plunge into
the ground and disappear, except during very heavy rains, when
the surplus waters are carried off by gravely channels in the chalk.

The principal object of the paper is to describe the seven swallow
holes between Clear Park and Farnham Park, anda minute account
is given of each. They occur in Clear Park—Lower Old Park Gully—
Clay-pit Gully—near the Potter’s Clay-pit—in the Hop-grounds,
above the turnpike a little west of the Odiham-road—near the en-
trance of the pleasure ground in Farnham Park—and near the end of
the avenue at the east of Farnham Park. ‘The water absorbed by the
holes in Farnham Park is supposed to reappear at the Bourne-Mill-
stream; and though soft where it sinks into the chalk, itis hard and
unfit for use, where it again breaks forth. ‘The existence of under-
ground currents was further proved by a well sunk at Hale Farm,
which gave the following section :

pana wig ravel LHS. Ve eee Pee acs 6 feet.
May GOULGES WT. ass oe Us he as Os Ke nee 15 or 16.
PUMUrEMa PTAVEL TL te te an ae tees cee ees 20.

EVR US a aan OP Pe 14 or 15.
Clay, blue (London?) lowest 2 feeta green sand 24.
PENS Eh. ee ene pee ate es ane ‘es ae 20 or 30.

At that depth a spring was reached, which was supposed to be the
Bourne-Mill-stream, and the instrument went down rapidly many
fathoms, through a chalk mud. ‘The well-sinkers afterwards came
upon chalk with many flints, and finally breaking their instrument,
left 80 feet of it in the earth, having bored altogether to a depth of
176 feet.

The green-sand tract, described in the second part of the memoir,
and drained by a stream which flows northward through a gap in
the chalk at Runfold into the London basin, is bounded on the north
by the straight line of the Hog’s Back, and on the south by a semi-
circular range of the low hills extending from Seale on the east by
Crooksbury Hill to Moor Park on the west. The surface of the tract
being sandy and naturally bibulous, the proprietor of the farm has ren-
dered it more retentive by a system of marling, and the rain water
being consequently less absorbed than formerly, it is collected in an
excavation called White-ways End Pond, at the western end of the

510 Geological Society.

Hog’s Back. From this pond a small stream flows towards Run-
fold, and passing thence across the depressed chalk, continues its
course to the county stream, or Blackwater river, receiving appa-
rently a small augmentation from a spring at Andrew’s hop-kiln.
This gap in the chalk at Runfold, not having been hitherto noticed
by geologists, Mr. Long conceives, that it deserves to be recorded
among the apertures of the North Downs.

An extract was last read from a letter addressed to Mr. Lyell by
Capt. Charters, F.G.S., and dated Cape Town, Nov. 12, 1838.

During an extensive tour through the colony, Capt. Charters’s
attention was drawn to a vast deposit of greenstone, overlying the
horizontally stratified sandstone which occupies so large a portion of
Southern Africa. The following localities are mentioned in the letter.
A hill close to Fort Beaufort, on the Kaffir frontier. The banks of the
Great Fish River, near the small town of Cradock, in the neighbour-
hood of which quantities of spherical masses of trap are heaped to-
gether, the surrounding sandstone mountains being of considerable
elevation, and having their flanks and sometimes their tops very fre-
quently covered with loose fragments of trap. On the right bank of
the river and about a mile from the town, is exhibited a section,
consisting in the lowest part of inclined strata of clay slate, in the
middle of horizontal beds of sandstone, and in the uppermost of
masses of trap. ‘The same geological structure prevails in passing
through the Tanka district, behind the Winterberg range to Shiloh,
and thence to Colesberg, near the Orange river, From Colesberg,
Captain Charters proceeded to Graf Keynet by the Schneeberg, and
he found that the only variation in the nature of the country consisted
in a considerable diminution of the quantity of greenstone. The left
of a narrow gorge through which the Sunday river passes, presents
an abrupt precipice 300 feet high and as many yards long, composed
of columnar greenstone resting at its foot on horizontal strata of
sandstone.

March 13.—A paper on the geology of the North Western part of
Asia Minor, from the peninsula of Cyzicus, on the coast of the sea
of Marmara, to Koola, with a description of the Katakekaumene, by
William John Hamilton, Esq., Sec. G.S., was read.

The memoir is divided into two parts, the first containing an ac-
count of the country between Cyzicus and Koola, the second a
description of the Katakekaumene.

The line of route taken by Mr. Hamilton from Cyzicus, ascends
the valley of the Macestus to the sources of that river near Simaul,
then crosses the Demirji chain, and afterwards passes through Kars-
kieui and Selendi to Koola, in the Katakekaumene, the whole distance
being about 170 miles. ‘The principal leading feature of the district
is the Demirji chain reaching from Pergamum on the west, to the lofty
mountain of the Ak Dagh or Shapkhana Dagh on the east, and it is
prolonged in that direction by a lofty range which extends E.S.E.
to Morad Dagh, south of Kutahiyah, and thence by Aiom Karahissar to
Sultan Dagh, an extension of one of the chains of Mount Taurus,
so that the Demirji range forms a portion of the central axis of Asia

Geological Society. 511

Minor. The country traversed by Mr. Hamilton is also intersected
by numerous hills, some of which exceed 1200 feet in height. The
lake of Maniyas is another marked feature in the district. The for-
mations of which the country is composed, are,—1, schistose rocks
with saccharine marble; 2, compact limestone resembling the scaglia
of Italy and Greece; 3, tertiary sandstones; 4, tertiary limestones ;
5, granite; 6, peperite; 7, trachyte; 8, basalt. Between Kespit
and the Demirji chain is a deposit of white marl, which Mr. Ha-
milton is of opinion, was accumulated in an ancient lake drained
by some of the igneous operations which dislocated the horizontal
tertiary limestone, and formed the traverses in the high hills between
Kespit and Susugerli.

1. The schists are composed of gneiss, mica slate, and clay slate,and
they are associated with crystalline limestone. Argillaceous schists
and marble occur between Cyzicus and Erdek; and thickly wooded
hills, 1000 feet in height, which rise abruptly from the shore of the
sea of Marmara, are capped by a fine marble. A little further
eastward are extensive quarries of the same stone, to which Cy-
zicus was partly indebted for having been ranked among the
most splendid cities of antiquity. The limestone is interstratified
with indurated marls and shales of various colours; the whole dip-
ping from 70° to 80° S.E. by S.: and near Erdek S.W., or in each
instance from the granitic nucleus of Cyzicus. Similar schists occur
in the Demirji range, and in the Katakekaumene, associated with
limestone.

Between the 33rd and 34th miles from Simaul towards Koola, is
a low ridge of hills of saccharine limestone, rising above the plateau
of horizontal limestone, and belonging to the same formation as the
hills about Koola. In the Katakekaumene, the older system of yol-
canic cones is situated on these schists, and the newer in the ad-
jacent alluvial plains, an important distinction accounted for in the
description of that district.

2. Compact Limestone resembling the scaglia of Italy and Greece
occurs only south of the lake of Maniyas, and at the foot of the range
of hills near the town of the samename. It is associated with beds of
shale. A micaceous sandstone, which forms a range of broken and
water-worn hills between Miilverkieui and the valley of the Susugerli
or Macestus, is considered by Mr. Hamilton, to be perhaps of the age
of this limestone, as well as the high and broken range of hills be-
tween Ildij and Kespit.

3. Tertiary Sandstones,—Vhis formation is very extensively deve-
loped, and consists of micaceous sandstones, sands, marls, and shales.
No organic remains were noticed in it by the author. It ranges
southward from the village of Susugerlifor about two miles. At the
eastern extremity of the Demirji chain, where it was traversed by
Mr. Hamilton, thinly laminated micaceous sandstone rests against
the granitic nucleus, and extends thence to the South for nine
miles. This formation is also exhibited about 16 miles from Simaul,
underlying irregularly and conformably the peperite, and at the 18th
mile the junction between the peperite and the sandstone is well ex-

512 Geological Society.

hibited. The lower volcanic beds are contorted, and consist of large
masses and boulders of primary, igneous, and scoriaceous rocks; the
beds, however, gradually become finer in the ascending order, and
nearly horizontal in their position. In the sandstone the author
noticed no fragments of volcanic matter. At the 19th mile, how-
ever, there appears to be a gradual passage or interstratification be-
tween the upper beds of the sandstone and the lower beds of the
peverite. The sandstone and peperite extend along the valley of
the Selendichai, and the former constitutes the hills between the
valleys of the Selendi and the Hermus, and is capped by the white
limestone. ‘The beds throughout the country are nearly horizontal,
except where they have been disturbed by igneous rocks.

4. Tertiary Limestone. This deposit Mr. Hamilton considers as
belonging to the great lacustrine formation which occupies so large
a portion of Asia Minor, but within the range of country described
in this paper, it appears to be destitute of organic remains. It pre-
sents table lands composed of beds of white, compact, or thinly la-
minated limestone resembling chalk, and sometimes containing no-
dules of opaque white flints, and sometimes extensive beds of tabular
flint. Near Kespit it is chalky, as well as 8 miles further south. It
forms the hill on which stands the castle of Bogaditza, at the south-
eastern extremity of the plain of the same name. South of the De-
mirji chain, and about eleven miles from Simaul, a white limestone
overlies peperite, and a few miles further, rests upon trachyte. About
the 19th mile, trachytic conglomerate overlies horizontal beds of white
marl irregularly associated with beds of quartz pebbles. Between the
valleys of the Selendi and the Hermus white limestone rests upon
the micaceous sandstone, the volcanic products having thinned out.
About the 35th mile, in the bottom of a ravine, Mr. Hamilton
noticed the following section :

Lowest part, gravel and loose beds of sand.... 30 feet.
Alternations of marls and sands, the former pre- ( 90 d
dominating in the upper part .......... a

stone. The hill above the ravine is capped by basalt in some places 100
feet thick, but a stratum of sand is occasionally interspersed between
the limestone and the basalt. South of the Hermus an insulated
patch of limestone is also overlaid by basalt, and around its base are
lava streams which have flowed from the volcanic cones near Koola,
The lower part of this patch of limestone is converted into a yellow
jasper-looking substance, with a bright conchoidal fracture.

5. Granite occurs near Cyzicus, where it is a finely grained, gray
rock, which decomposes rapidly; but it contains large masses of
hornblende, and is sometimes traversed by veins of felspar. It throws
off the adjacent schistose rocks, which dip from it in opposite di-
rections. Granite apparently forms also the axis of the Demirji
range.

6. Peperite.—This deposit is extensively developed in many parts
of Asia Minor, It is distinctly stratified, but it has sometimes a

Ve eee ee

Geolagical Society. 518

crystalline or vitreous aspect, and contains crystals of hornblende
as well as much glassy felspar. Within the range of Mr. Hamilton’s
route it occurs about 24 miles south of the village of Susugerli;
also 9 miles south of Simaul: and a little further the author ob-
tained the following descending section :

1. Hard volcanic tuff, slightly crystalline, but containing many
boulders and pebbles of trap, with numerous concretions of green
marl, 12 feet.

2. Soft whitish volcanic earthy tuff, containing small frag-
ments of pumice, 10 feet.

3. Hard crystalline but stratified rock.

About the 11th and 12th miles from Simaul, peperite is overlaid
by a white limestone ; between the 15th and 16th it rests upon pro-
truded masses of decomposing trap or syenite; and half a mile
further a mass of trachytic or trap conglomerate, forming the point
of separation of two valleys, has been raised up subsequent to its de-
position by a protrusion of trap, as the conglomerate, which is much
contorted, adheres to the side of the trap; and near the 16th mile,
it is underlaid by the micaceous sandstone.

The beds are occasionally horizontal, but where the peperite has
been affected by the trachyte, they are variously inclined.

7. Trachyte and Trachytic Conglomerate.—Several varieties of this
rock occur within Mr. Hamilton’s district. The points more par-
ticularly mentioned are, one mile south of Kespit, where it forms a
ridge of hills; the village of Kalburja, 7 miles 5.W. of Kespit;
also near the town of Bogaditza, whence a high trachytic range ex-
tends for a considerable distance east and west, succeeded by a less
elevated district of the same rock, which continues beyond Sin-
gerli to the foot of the Dimirji mountains. In this district the tra-
chyte varies greatly in colour, is generally soft, decomposes easily,
and the author was often unable to decide whether it was an aqueous
deposit of voleanic sand, or a subaqueous igneous rock. ‘I’o the east
of Singerli is a large mass of red porphyritic trachyte, considered by
Mr. Hamilton to be a coulée which has flowed from the high rugged
hills to the south-east. The trachytic rocks continue up the valley of
Macestus for several miles. It is also extensively developed south of
the Demirji chain between Simaul and Koola, particularly about the
13th or 14th mile from the former, and is overlaid by white lime-
stone. About the 19th mile, in some places, cliffs of trachytic conglo-
merate rest upon the peperite, and in others the trachytic conglo-
merate overlies horizontal beds of white marl belonging to the white
limestone, and interstratified as before stated, with irregular beds of
quartz pebbles.

8. Basalt is exposed south of the Demirji chain at several places,
but more particularly near and in the Katakekaumene.

A spur of porphyritic trap occurs about two miles south of Su-
sugerli.

Hot Springs burst forth in great force about 74 miles east of
Singerli. ‘Their temperature is supposed by Mr. Hamilton to be
equal to that of boiling water. Extensive depositions, in one part

Phil, Mag, 5.3. Vol. 14. No. 92. Suppl. July, 1889. 2.L

514 Geological Society.

8 or 10 feet thick, occur around the mouths of the springs ; and a’
strong sulphureous smell accompanies the emission of the water; but
where the temperature had become sufficiently low to permit the
water to be tasted, no peculiar flavour was perceived. After flowing a
mile and a half and turning several mills, the water is used for a
warm bath. The rock from which the springs rise, is a greenish
brown porphyritic trap. Some copious hot springs issue near the
lower beds of the tertiary white limestone, a little north of Koola,
the temperature varying from 123°to 137° Fahr. ‘Two of them are
situated in the centre of the ruins of an unknown ancient city. Mr.
Hamilton perceived a slight development of sulphuretted hydrogen
gas.

The Katakekaumene.—The extent of this interesting tract is much
less than is assigned to it in published maps, being not more than 7
miles from north to south, and 18 or 19 from east to west. After
alluding to his first visit to it in company with Mr. H. E. Strickland,
and referring to that gentleman’s account of a portion of the district*,
Mr. Hamilton describes minutely the two systems of volcanos, di-
stinguished by the state of preservation of the craters and of the
coulées; he defines also the course of each lava-current, and points
out its attendant phenomena—but these details admit of only partial
abridgement.

The volcanic products are basalt, lava, and ashes, the first being
confined to the more ancient craters, and the last to the more modern.
The numerous older cones are further distinguished by being situated
on parallel ridges of gneiss and mica slate, and the newer, only three
in number, by being confined to the intervening alluvial valleys.
This important distinction Mr. Hamilton explains on the supposition,
that the elevation of the schistose ridges produced cracks, through
which, as points of least resistance, the first eruptions of lava found
vent ; and that these openings becoming subsequently plugged up,
by the cooling of injected molten matter, the schists were rendered
so solid, that when the volcanic forces again became active, the lines
of least resistance were transferred to the valleys.

The coulées from the ancient craters appear to have been partly
under water, as their surface is, in some places, covered with sedi-
ment and turf; but the lava streams from the modern are bare, rugged,
and barren, and the craters are surrounded by mounds. of loose
scorie and ashes. In addition to the comparative view given by
Mr. Strickland of the phenomena of the Katakekaumene and Central
France, Mr. Hamilton enters into a more extended investigation of
points of resemblance, including other portions of Asia Minor. The
great volcanic groups of Mont Dore, the Cantal, and Mont Mezen,
Mr. Hamilton conceives are represented by Ak Dagh, Morad Dagh,
the trachytic hills east of Takmak, Hassan Dagh, and Mount
Argeus. The modern volcanic period of Central France he com-
pares with the Katakekaumene, as respects the composition of the
lavas, their arrangement at different levels, and the cones being

* See L. & E, Phil. Mag, vol. x., p. 70,

Geological Society. 515

seattered, not collected in great mountain masses. The Katake-
kaumene, in Mr. Hamilton’s opinion, exhibits also additional evidence,
that the disposition of comparatively recent volcanos is coincident
with the strike of the granitic axis, from the interior of which the
volcanos have burst forth. The author also alluded to other com-
parative phenomena noticed in Mr. Strickland’s paper. Lastly, he
pointed out two distinctions :—in Central France streams of igneous
products may be traced from the most ancient volcanic masses
of Mont Dore, but in Asia Minor none have been detected which
could have flowed from Ak Dagh, or Morad Dagh. In France,
also, trachytic eruptions occurred during the deposition of the lacus-
trine limestone; but in the Katakekaumene, they appear to have
preceded that of the white limestone, or are associated with only its
lowest beds.

In conclusion, the paper gives a general summary of the geological
phenomena of the country south of the Demirji range.

The relative antiquity of the vast lake or sea in which the strata
were deposited, cannot be determined, as the micaceous sandstone
forming the lowest series of beds is apparently destitute of organic
remains, and Mr. Hamilton, therefore, does not attempt to compare
that deposit with any European formation. The sandstone, he con-
ceives, was accumulated upon an irregular surface of schistose
rocks and crystalline limestone, and before the elevation of the
Demirji chain. Upon the sandstone were deposited in the north of
the district the beds of peperite, derived probably from subaqueous
voleanos; and upon the peperite and the micaceous sandstone, the
white limestone, which is the highest sedimentary rock. ‘The drain-
age of the lake, he is of opinion, took place during the earliest
voleanic eruptions of the Katakekaumene.

Three well-defined periods of igneous operations may be traced.
The first is marked by the masses of basalt which cap some of the
plateaux of white limestone, and were ejected previously to the
country assuming its present configuration, and to the formationof the
valleys. Mr. Hamilton considers that the basalt flowed under water,
and probably but a short time before the drainage of the lake.

The second period is characterized by the currents of basalt and
lava from the ancient system of volcanos in the Katakekaumene,
and was subsequent to the formation of the present valleys, as
many of the lava streams may be traced into them. The coulées
which flowed towards the Hermus from the crater or Karadevit near
Koola, present an inclined plane, the surface of which is not more
than 150 or 200 feet above the present bed of the river; but they
must, at one period, have been under water, as the lava is covered
with a sediment which fills its crevices and smooths its asperities.

The third period belongs to the more modern system of cones,
the lava of which is as rugged and barren as the recent coulées of
Etna and Vesuvius. Of the date of these eruptions, Mr. Hamilton
offers no opinion, merely remarking that the craters are mentioned
by Strabo, and that there is no tradition of their activity.

March 27,.—A paper was read by Prof, Owen, F.G.S., entitled a

2L2

516 Geological Society.

*« Description of a Tooth and part of the Skeleton of the Glyptodon,
a large quadruped of the Edentate order, to which belongs the tes-
sellated bony armour figured by Mr. Clift in his memoir on the re-
mains of the Megatherium, brought to England by Sir Woodbine
Parish, F.G.S.”

The first notice of the remains of a fossil large edentate Mammal
associated with a tessellated bony armour, is an extract from a letter
addressed by Don Damario Larranaga, Curé of Monte Video, to
M. Auguste St. Hilaire, and appended to Cuvier’s account of the
Megatherium in the Ossemens Fossiles, t. v.p.179.(1823). The bones
were discovered near the surface in alluvium, in the Rio del Sauce,
a branch of the Saulis grande, and consisted of a femur 6 to 8
inches in width, but short, and in every respect like the femur of an
Armadillo; also a portion of a tessellated bony armour. The tail is
described as very short and very stout, and to have had a bony
armour, which was not verticellate or disposed in rings. Similar
fossils are said to occur in analogous strata near the lake Mirine, on
the frontier of the Portuguese colonies. ‘The notion that the remains
found in the Rio del Sauce belonged to the Megatherium, rests solely
on the circumstance of Don Damario Larranaga having inserted the
word Megatherium as the synonym of his gigantic fossil ‘‘ Dasypus.”
Je ne vous écris point sur mon Dasypus, (Megatherium, Cuvier.)

The next observations bearing upon the present subject are con-
tained in Weiss’s Geological Memoir on the provinces of San Pedro
do Sul, and the Banda Oriental, (Berlin Trans., 1827). These re-
mains consisted of part of a femur of a Megatherium, without any
associated armour, found at a deserted Indian camp near the Queguay,
a tributary of the Uruguay ; of portions of osseous tessellated armour,
apparently unaccompanied by bones, discovered on the Arapey chico,
in the province of Monte Video; and of bones of the extremities
and fragments of armour found near the Rio Janeiro. The whole of
these remains were collected by Sellow, the Prussian traveller, and
after his death the last-named collection of bones and armour were
submitted to Prof. D’Alton, by whom they have been described,
(Berlin Trans., 1833,) and who states, that they are not the remains
of the Megatherium, but of a large edentate animal more nearly allied
to Dasypus.

In 1832, Mr. Clift laid before the Geological Society a memoir
on the remains of the Megatherium brought to England from Buenos
Ayres by Sir Woodbine Parish*. In the collection of which they
formed a part, were fragments of bony tessellated armour, one
of which was figured but not described by Mr. Clift, because the
fragments were not associated with the remains of the Megatherium ;
there were also a portion of a jaw and several other bones, which
were found in connexion with portions of a bony armour in the bed of
arivulet at Villanueva, about 95 miles south of Buenos Ayres. On the
examination of the last-mentioned remains when they first arrived in
England, it was evident both to Mr. Cliftand Mr. Owen, particularly
from the conformation of the alveoli in the jaw, that the bones did

* See L. & E. Phil. Mag. vol. i, p. 233.

——o

Geological Society. 517

not belong to the Megatherium ; and that the dentition of the extinct
species differed more widely from that of the existing subgenera of Ar-
madillos than the respective dental characters of the latter differ from
each other. As the portions of the skeleton were not sufficient to en-
able Mr. Clift to determine satisfactorily the characters of the animal,
no account of them was given in his memoir on the Megatherium, but
they form the subject of Mr. Owen’s paper, of which this is a notice.
Soon after the arrival of Sir Woodbine Parish’s collection, the Col-
lege of Surgeons had casts made of the bones, and presented them to
different museums, including the Jardin du Roi, where they were
examined by M. Laurillard and Mr. Pentland. These naturalists
also concluded, especially from the bones of the foot, that the re-
mains were not portions of the Megatherium, but of a gigantic
Armadillo.

More recently, Sir Woodbine Parish received an account of the
discovery, in the bank of a rivulet near the Rio Matanza, 20 miles
south of the city of Buenos Ayres, of a perfect skeleton and bony
covering, and with the description, he also received a fragment of
a tooth and a drawing of the animal. On examining the tooth, Mr.
Owen found, that it belonged to an animal referable to the Edentata
of Cuvier, but indicative of a new sub-genus of the Armadillo family ;
and for which he proposed the name of Glyptodon, in reference to
the sculptured character of the tooth. Subsequently, he compared
the tooth with the alveoli in the fragment of the jaw in Sir Wood-
bine Parish’s collection; and he found that the peculiar longitudinal
ridges in the sockets precisely corresponded with the flutings in the
tooth itself, whereby he was enabled to prove, that the bones dis-
covered with the tessellated coat of mail at Villanueva appertained
to the same species as the more perfect skeleton and cuirass found
near the Rio Matanza.

Judging from the drawing transmitted to Sir W. Parish, the Glyp-
todon differs from the Megatherium not only in the form and struc-
ture of the teeth, but in the number, which appears to be eight on
each side of each jaw; and from all known Armadillos in the form
of the lower jaw, as well as in the presence of a long process de-
scending from the zygoma, in both which respects it resembles the
Megatherium. According to the same figure, the tail was protected
by a narrow bony covering on the upper surface only, and was not
encompassed by it as in the Armadillos.

Mr. Owen then proceeds to describe the remains of the Glyptodon
which have arrivedin England. ‘The molar tooth is only a fragment,
but the grinding surface and upwards of an inch of the crown are
perfect, the whole length being about two inches. There is no in-
dication of a diminution in any of its diameters from the grinding
surface to the opposite end, and the alveoli in the fragment of the
jaw terminate abruptly without any contraction. ‘The teeth are
more compressed than those of the Megatherium, and differ from
them in intimate structure, resembling in this respect the teeth of
the Armadillos. From all known Armadillos, the Glyptodon, how-
ever, is distinguished by the tooth having on both the outer and inner

518 Geological Society.

surfaces two deep grooves, each extending from the opposite sides
about one third of the transverse diameter of the tooth and through
its whole length, dividing the grinding surface into three portions,
joined together by the contracted isthmus interposed between the
opposite grooves. The teeth thus exhibit a more complicated form
than those of any known Edentate, and seem to indicate a transition
from that family to the Pachydermal Toxodon.

The fragment of the jaw discovered at Villanueva consists of a
portion near the extremity of the left ramus, and includes three
alveoli, which slightly increase in size as they are placed further
back.

The humerus, of which the distal half has been received, agrees
most nearly with that portion of the humerus of the Dasypus, but
the internal condyle is not perforated ; the depressions also above the
trochlea, both in front and behind, are relatively deeper, and in the
side opposite the deltoid trochanter there is a rugged raised surface
for a muscular insertion, of which Mr. Owen has not perceived any-
thing analogous in the Armadillos. From the humerus of the Me-
gatherium it differs in not presenting the extraordinary expansion of
the distal extremity exhibited in that animal; but the internal con-
dyle in the Megatherium is also imperforate.

The radius of the Glyptodon corresponds very nearly with that
of the Armadillo, but it differs from the radius of the Megathere in
being three times less in every dimension, and by well-marked dif-
ferences in all the details of structure.

The ungueal phalanges of the Glyptodon approach most nearly
those of the species of Dasypus; but in their shortness, as compared
with their breadth and depth, they resemble still more the ungueal
phalanges of the Pachyderms. Mr. Owen is of opinion that they
were encased in strong, short, hoof-like claws; and that they exhibit
rather the base of an anterior column of support to an animal clad
in a ponderous cuirass than instruments especially designed for
scratching or digging. There cannot be a greater contrast than is
presented between the short, broad, and flat phalange of the Glyp-
todon, and the long and compressed claw-bone of the Megatherium,

Of the posterior extremity of the Glyptodon, the tibia, which is
anchylosed to the fibula, presents the structure characteristic of the
tibia of the Armadillos; while in the Megathere the corresponding
bones deviate widely in their proportions, and in the conformation of
the distal articular surface from those of the Glyptodon. The con-
formation of the astragalus, caleaneum, the cuboid, scaphoid, and
internal cuneiform bones, also of the metatarsals of the three middle
and largest toes, the three phalanges of the second and middle, and
the distal phalanges of the third and fourth toes, were described in
great minuteness, but it is not possible to abridge the details.

Mr. Owen, however, stated that when the bones of the hinder ex-
tremity are arranged in their natural juxta-position, they present a
foot of such singular proportions as to be without a parallel in the
animal kingdom. The nearest approach to its broad, thick, short, and
massive proportions is made by the skeleton of the fossorial extremity

Geological Society. 519

of the Mole ; but it is the fore foot only of this animal that can be com-
pared in the compressed figure of the metacarpals and proximal and
middle phalanges with the singular hind-foot of the Glyptodon. The
hind foot of the Mole resembles in the lengthened metatarsal and pha-
langeal bones that of the existing Armadillos, and the generality of
quadrupeds. ‘The true structure of the hind foot of the Megatherium
is not known, but in the terminal phalanges it differs most widely
from those of the Glyptodon. In the former, the compressed length-
ened shape is as extreme in the claw-bones as, in the latter, is the
depressed, shortened figure. In the Glyptodon, the hind foot, like
the fore, appears to be expressly modified to form a base to a column
destined to support an enormous superincumbent weight; while in
the Megatherium the toes were free to be developed into long and
compressed claws, such as form the compensating weapons of de-
fence of the hair-clad Sloths and Ant-eaters. The ungueal phalanges
of the Armadillos, in their shorter, broader, and flatter form, make a
much nearer approach to those of the Glyptodon ; and it may be
readily admitted that the hind foot of the Glyptodon is an extreme
modification of the same general plan of structure as that on which
the foot of the Armadillo is constructed; but if the differences in
the tarsal bones (described in the paper) exceed those which are
traceable between one species of Armadillo and another, « fortiori, the
antero-posterior compression of the metatarsals and phalanges, and
the total suppression in those of the ginglymoid trochlear articula-
tions are indicative of a difference of general habits, as great as is
usually observed in animals of distinct but nearly-allied genera. Thus
both the dental modifications and the locomotive organs prove that
the Glyptodon cannot be called an Armadillo without making use of
an exaggerated expression ; still less can it be considered a species
of Megatherium ; but it offers the type of a distinct genus, which is
much more nearly allied to the Dasypodoid than to the Megatherioid
families of Edentata. For this genus Mr. Owen had proposed a name
indicative of its dental peculiarities, and, as the present species agreed
with the Armadillos in its dermal armour, he preferred the name of
Glyptodon clavipes, in relation to the peculiar modification of the
foot.

Mr. Owen then showed that the portions of tessellated armour
described and figured by Weiss are identical in structure with those
brought to England by Sir Woodbine Parish, and that the bones
which were found with the armour in both cases belonged to animals
specifically identical. He next entered upon the inquiry, Had the
Megatherium a bony armour? and he concluded from a comparison of
its skeleton with that of the Armadillos, that it had not, In the pelvis
of the Armadillo there are twelve sacral vertebrae anchylosed to-
gether, and the spines of the vertebrze are greatly developed antero-
posteriorly, forming a continuous vertical ridge of bone, bearing im-
mediately the superincumbent weight. In the Megathere the sacral
vertebra are only four in number, and are not anchylosed, and the
spinous processes are comparatively small, not locked together, as in
the Armadillos, but separated by intervals as in the Sloths. In the

520 Geological Society.

Armadillos, the weight of the cuirass is transferred from the sacrum
to the thigh-bones by two points on each side. One of them, the
ischium, is anchylosed to the posterior part of the sacrum, the other
point is formed by the conversion of the iliac bone into a stout three-
sided beam passing straight from the thigh-joint to abut against
the anterior part of the sacrum, where the weight of the shell is
greatest,—a structure which is wanting in the Megathere. In no
species of Armadillo is the ilium expanded, while in the Megathere
it is greatly developed, resembling that of the Elephant in size, form,
and position ; and among the Edentata the nearest approach in this
portion of the skeleton is to be found among the Sloths and Ant-eaters.
The most striking point however, in the structure of the Armadillos,
with reference to the support of a bony covering, is the remarkable
production of a part of the vertebra from above the anterior articular
process on each side, in a straight direction upwards, outwards, and
forwards, to nearly the height of the true spinous processes. Now,
these oblique processes, which are developed only in the loricated
Edentata, beautifully correspond in form and use with the tie-bearers
in the architecture of a roof, and are entirely wanting in the Me-
gathere, the structure of this part of the vertebral column of that
animal corresponding with the character of the vertebre of the hair-
clad Sloths and Ant-eaters. Mr. Owen noticed other supposed adap-
tations in the skeleton of the Megathere to sustain a bony covering,
as the breadth of the ribs, but the ribs of the Sloths and Ant-eaters
are broader than those of the Armadillos.

The paper contained a tabular account of the discovery of twelve
skeletons of the Megathere, and in no instance did any portion of
bony armour occur with or near the bones. A notice was also given
of the remains of a Glyptodon, found in the left bank of the Pedernal
before its junction with the Sala, an affluent of the Rio Sante, near
Monte Video, and preserved in the museum of that town. From
the accounts which have been given of these remains they appear to
have belonged to the same species as that described in the paper.
An allusion was also made to some portions of bony armour ob-
tained in the Rio Seco, in the Banda Oriental, and similar in struc-
ture to the specimen of the Pedernal. One of the portions was
the covering for the tail. It was hollow to its extremity, and pre-
sented in its concavity, vestiges of caudal vertebre very distant from
each other.

In conclusion, Mr. Owen observes, that having brought together
evidence of the remains of five specimens (found in the Rio Seco,
Rio Janeiro, Villanueva, Pedernal, and the Banda Oriental) of a
large Edentate species undoubtedly covered with armour, and more
or less corresponding with the characters of the Glyptodon, and
having established the characters of that genus on both dentary and
locomotive organs; he trusts that he has at the same time vindicated
the opinion of Cuvier with reference to the Megathere, by proving
it to be, by its tezumentary covering as well as its osseous system,
more nearly allied to the Ant-eaters and Sloths than to the Ar-
madillos.

a rd Pr -_
Se ee ee ee

“Aidan Tissseh eae

Astronomical Society. 521

ASTRONOMICAL SOCIETY.

March 8.—The following communications were read :—

Observed Transits of the Moon, and Moon-culminating Stars,
over the Meridian of Edinburgh Observatory, from June 1 to De-
cember 31, 1838. By Professor Henderson.

Lunar Oécultations of Planets and Fixed Stars, and Eclipses of
Jupiter’s Satellites, observed at Edinburgh Observatory in 1838.
By Professor Henderson.

Moon-culminating Stars observed at the Cambridge Observatory
in the Months of November and December, 1838. By Professor
Challis.

Occultations observed at Dulwich and Ashurst, from July 31 to
December 27, 1838. By Robert Snow, Esq.

On the Method of determining the Longitude by Moon-culmina-
ting Stars. By Mr. Epps, late Assistant-Secretary to the So-
ciety.

The author remarks, that the advantages of moon-culminating ob-
servations, for the purpose of determining the difference of longi-
tudes, particularly in the case of distant meridians, are now univer-
sally admitted, every other method being found subject not only to
greater trouble and difficulty, but to errors far exceeding the limits
of those to which the results of moon-culminating observations are
liable. But although this method, the merit of introducing which
belongs chiefly to Mr. Baily, is justly regarded as the best known,
yet the result of a single observation, or of a few observations, is
liable to a considerable amount of error, even when the observations
are made by the best instruments and the ablest observers; and the
object of the present communication is to show the extent to which
the error may be expected to reach.

The moon’s proper motion, on which the method entirely depends,
is such, that an error in the observation is necessarily greatly aug-
mented in the resulting longitude; in fact, the error in longitude
will always be from 21 times to 35 times the amount of the error of
observation. If, then, it be assumed that 0*:2 of time is the pro-
bable error of an observed transit, and that the observed interval be-
tween the transits of the moon and star is liable to an error of 054,
the resulting difference of longitude will be in error from 8 to 14
seconds of time. This is the probable effect, from observations made
at one station only; and as it is quite possible that the effect may
be doubled by an equal amount of error, in a contrary direction, at
the other station, the author thinks he will be within limits in as-
suming 10 or 12 seconds of time as the probable error of longitude,
resulting from the comparison of a corresponding interval observed
at two stations, admitting that the best means of making the obser-
vation exist at each.

In order to show that the probable error is not overrated, by as-
suming it to amount to 10 or 12 seconds, the author refers to two
lists of results given by Professor Henderson, in the introduction to
the first volume of the Edinburgh Astronomical Observations. One

522 Astronomical Society.

of these lists contains the computed differences of longitude between
Edinburgh and Greenwich, and the other between Edinburgh and
Cambridge; each contains 36 combined results, some of which
differ by a much greater quantity than the probable error above
assumed. The mean of all the results, as deduced by Professor
Henderson, likewise shows the degree of approximation which the
method may be considered as capable of giving, in the most favour-
able cases. Each of the lists referred to’consists of a mean of the
differences of the observed intervals at the two places on the several
days stated, so that each series of results contains about 100 corre-
sponding intervals ; and, consequently, the final difference of lon-
gitude, deduced from each list, is the mean result of 36 mean quan-
tities, deduced from about 100 corresponding intervals, observed at
both stations. In fact, there are 136 corresponding transits made
at Edinburgh and Greenwich, and 133 at Edinburgh and Cambridge ;
and from all these the difference of longitude between Greenwich
and Cambridge comes out = 13™ 585 — 12™ 448-4, or 211. But
the difference of the longitude of the two places, ascertained by
other means, and, doubtless, with scrupulous exactitude, is 238-54;
so that the final result of the moon-culminating observations is wide
of the truth by more than 2 seconds of time.

The author concludes by observing, that the results here referred
to, instead of tending to depreciate the method, may be considered,
on the contrary, as affording proof of its excellence ; for, in respect
of distant meridians, an error of 2 seconds is undeserving of notice.
It is however evident, that, considering the inferiority of instruments,
and other sources of error incident to a temporary station, a tolera-
ble degree of accuracy can only be expected from an extensive series
of corresponding observations.

On the Position of Lacaille’s Stations at the Cape of Good Hope.
By Thomas Maclear, Esq. M.A. F.R.S., Astronomer Royal at the
Cape. Communicated by Captain Beaufort, R.N. F.R.S. This
paper was in part read.

April 12.—The reading of Mr. Maclear’s paper, on the Position
of Lacaille’s Stations at the Cape, was resumed, and concluded.

The astronomical celebrity of the Abbé de Lacaille’s visit to the
Cape of Good Hope in the last century, together with the remark-
able results deduced from his arc of the meridian, naturally prompted
Mr. Maclear to become acquainted with his stations, and to connect
the southern, which was his observatory, with the present Royal
Observatory. In undertaking this task, he soon found that the lapse
of eighty-five years had obliterated all local evidence of the French
astronomer’s operations; and the fact that he was there at all was
only kept alive by the inquiries of Captain Everest in 1821. Having
carefully perused the various Memoirs of Lacaille relative to his
Cape operations, as well as his printed Journal, Mr. Maclear applied
to his Excellency Sir Benjamin D’Urban, the governor of the colony,
for leave to inspect the official documents. This was readily granted ;
but although several letters and notices interesting to the astronomer
were brought to light, nothing was discovered tending to promote

ee eee

a

. Astronomical Society. 523

the object he had immediately in view, which was to identify the
spot on which Lacaille’s Observatory had stood.

Lacaille states, that he resided in the house of a person of the
name of Bestbier, on whose premises the Observatory was built.
Accordingly, Mr. Maclear undertook to trace the residences and
property of all persons of the name of Bestbier ; and he ascertained,
on searching the records of the Transfer Office, that only one per-
son of that name held property in Cape Town in the year 1751, and
he answered to the description given by Lacaille. By tracing down
the successive transfers of this property to the present time, Mr.
Maclear was led to the house in Strand Street, now occupied by
Mrs. De Witt; the house referred to by Captain Everest. This
lady permitted him to inspect her title-deeds and diagram, and they
were found to agree exactly with the records in the Transfer Office.
The position and form of the premises also corresponded with several
remarks made by Lacaille in describing his operations.

Having thus obtained undeniable proof of the identity of Best-
bier’s house with that now occupied by Mrs. De Witt, the search
for the position of the Observatory was brought within narrow
limits, for Lacaille states that it was in the court-of the house where
he lived. The author accordingly proceeded to take measures for
connecting the house with the Royal Observatory by triangulation,
resolving to spare no pains in the execution of this part of his ope-
rations, inasmuch as he entertained a hope that he should thereby
be able to ascertain whether Lacaille’s plumb-line had been affected
by the attraction of Table Mountain.

In the meantime, Mr. Maclear had communicated his views and
proceedings to Captain Beaufort, and Mr. Airy, the Astronomer
Royal, the latter of whom immediately wrote to the Secretary of the
Admiralty, requesting their Lordships’ permission to send out Brad-
ley’s zenith-sector, in order that Mr. Maclear might be enabled to
verify at once the amplitude of Lacaille’s arc. This was precisely
what he himself had wished to accomplish, provided he could iden-
tify the northern station.

The northern station, at Klyp-Fonteyn, cannot be so readily
traced as that in Cape-Town. On visiting the place, accompanied
by Lieut. Williams of the Royal Engineers, Mr. Maclear found
that a close investigation into the history of the proprietors, in con-
nexion with the buildings and ruins, would be necessary ; for, on
looking at the old foundation described by Captain Everest, as the
platform of the granary in which Lacaille had observed, and com-
paring its dimensions with Lacaille’s statement, and its position and
distance from the old house, so unlike the usual arrangements of
the Dutch farmers, he perceived strong reasons for doubting its
identity with the granary of Lacaille.

The platform alluded to by Captain Everest consists of a founda-
tion-wall 63 feet long, by 24 in breadth; a considerable portion
of it, on the west side, is’ two feet above the ground, and it is
situated at the distance of 630 feet from the old house. But La-
caille states that the place in which himself, Mr. Bestbier, and his

524 Astronomical Society.

assistant slept, was a part of the granary, 6 feet long, and 7 feet
wide, separated from that in which the sector was by a curtain,
which formed a sort of partition; and beyond was a little place for
the slaves. Now if this platform was the site of the granary inha-
bited by Lacaille, it is very difficult to account for these confined
dimensions. It can hardly be supposed that the place was filled
with grain, for Lacaille’s visit took place about a month before the
time of harvest. Besides, it was distinctly asserted by Ferrit Cot-
see, an aged inhabitant of the place, that the foundation in question
was the ruins of his father’s dwelling-house. It therefore became
necessary, in order to arrive at the facts, to inquire into the evi-
dence on which Captain Everest had fixed on the spot; to investi-
gate the truth of Ferrit Cotsee’s statement ; and, lastly, to examine
the place, by turning up the soil. As none of these plans could be
carried into execution immediately, Mr. Maclear, in the meantime,
returned to the Observatory.

Captain Everest’s statement, which is given in the first volume
of the Memoirs, p. 261, is as follows: “In reference to this matter,
it may not be amiss to mention, that the daughter of the quondam
proprietor of Klyp-Fonteyn, now an aged lady, named Letchie
Schalkevyk, is still in existence, and not only gives a narrative
perfectly agreeing, but has pointed out the very platform on which
the granary once stood.” On applying to Mr. Hertzog, the assist-
ant surveyor-general at the Cape, who had accompanied Captain
Everest to Klyp-Fonteyn, for information respecting the particulars
of their journey, Mr. Maclear ascertained that the aforesaid lady,
who appears to have resided at some distance, was not brought to
the place herself, but sent her son, who pointed out the site, ac-
cording to directions from his mother. The son himself could have
no local knowledge, for no one of the name of Schalkevyk had re-
sided at Klyp-Fonteyn within the memory of the oldest inhabitant
living in 1838; it may therefore be conceived that he would be
likely to point to the only ruin visible, as the site which his mother
had described to him from memory. ‘This evidence is obviously not to
be put in comparison with that of Ferrit-Cotsee, who had constantly
resided at the place during sixty-eight years, and remembered
having lived in the house over the foundation in question.

When preparing for his second journey to Klyp-Fonteyn, with
Bradley’s sector, Mr. Maclear applied to his Excellency General
Napier, and obtained a corporal of sappers and private from the ar-
tillery corps, under his former companion, Lieut. Williams. Arrived
at Klyp-Fonteyn, he found the widow of the brother of Ferrit Cot-
see, who had been married at the age of seventeen, forty-eight years
ago, and had known Klyp-Fonteyn ever since. At her marriage,
she lived with her mother-in-law, who died at the age of eighty,
and has been dead thirteen years. She had often heard her mother-
in-law speak of the French astronomer’s visit. When made ac-
quainted with Mr. Maclear’s object, she took him to a spot where
was a ruin in her early years, stated by her mother-in-law to be the
ruins of the house of Oker Schalkevyk, the father of the lady referred

ee ee

,
:

Astronomical Society. 525

to by Captain Everest. Nothing in the shape of a ruin was to be
seen; but the sappers were set to work, and, in a couple of days,
exposed the foundations of a building, 54 feet long by 12, with three
partition walls, and an oven at one end: evidently the site of a
dwelling-house, as had been described.

While this operation was going forward, Ferrit Cotsee pointed out
another spot, on which, he said, there had formerly been an old ruin.
The sappers were again set to work; and, at the depth of about 3
feet, encountered a wall, which they traced and cleared, with great
labour, in three or four days. This foundation, like the other, is of
stone and clay. It is 22 feet by 12, and generally from 2 to 3 feet
below the surface. Mr. Maclear attributes the depth to the sliding
down of the soil from above, the ground over it being much inclined.
Portions of chaff or short straw were found deep in the clay; but
little confidence could be placed in this, as affording indications of
a granary; for they might have been carried down by ants or mice.
Ferrit Cotsee could give no account of the purpose of this building

‘there had been no roofed building there within his recollection.

There were now three ruins exposed to view, and the question
arose, whether any one of these was the granary of Lacaille? The
first was asserted by Ferrit Cotsee to be the ruins of his father’s
dwelling-house ; the second was discovered exactly under the spot
which his sister-in-law, from his mother’s information, had described
as the site of Oker Schalkevyk’s house; with regard to the third,
there was no direct evidence, but it stood relatively to the others in
the position in whieh granaries usually stand in the country, and it
was difficult to conceive any other purpose to which it could have
been applied. Its dimensions were too contracted for a dwelling-
house, and its masonry too good for carrying the flimsy hut of a
hottentot or slave; which, besides, are not oblong, but circular, and
never of more substantial materials than mud, except at the mis-
sionary institutions. After a minute and careful comparison of all
the circumstances, Mr. Maclear came to the conclusion that the plat-
form of Captain Everest was the dwelling-house of Cotsee’s father,
as the son asserts it to have been, and that the granary was on the
foundation he had last exposed. This conclusion was subsequently
confirmed by an entry discovered among the colonial records, from
which it appeared that the proprietor of the place, in 1752, was
Cornelius Cotsee, the grandfather of Ferrit; and that Oker Schal-
kevyk, supposed by Captain Everest to be the proprietor, was not a
proprietor, but a householder, at the will of Cotsee. ‘The meridio-
nal distance of the granary from the platform of Captain Everest is
210 feet, or rather more than 2".

The signals at the other two angles of the triangle, namely, Rie-
beck’s Castle and Capoc Berg, were easily recognised. The charcoal
remnant of the signal-fire still remains on Riebeck’s Castle, and
was carefully covered up, by Mr. Maclear, with stones. ‘The top of
this rugged mountain, he observes, presents nothing inviting, and
the ascent is laborious and difficult: hence the reason of the ‘signal

526 Astronomical Society.

remaining undisturbed; whereby the party were enabled to enjoy
the sight of one undeniable mark of the work of Lacaille.

The author next proceeds to describe the operations for connect-
ing Lacaille’s southern station with the Royal Observatory. With
these he included another position, ‘‘ one which,’ he remarks,
“must ever excite the feelings and enthusiasm of the admirers of
genius, moral worth, and almost unlimited talent—namely, the scene
of Sir John Herschel’s recent labours.” This position being invi-
sible from the Observatory, and also from Cape Town, it became ne-
cessary to choose a fourth station ; and, accordingly, King’s Block.
house Battery was fixed upon, which commanded a view of the other
stations, and also of the base line.

The site of the base is on the sandy plane to the north of the
Observatory. The east end is defined by the centre of the meridian
pillar of the transit room; and the west, by a gun, let into a large
flag-stone, which was sunk in the ground to the depth of seven feet,
and firmly fixed by ramming down the soil. The line is so little
elevated above the sea, that a large portion of it is covered by water
at spring-tides.

Almost the whole of the apparatus for the measurement of the
base was constructed at the Observatory; and although the screws,
brass-work, &c. were homely in appearance, they sufficiently an-
swered the purpose. The twenty-feet measuring-rods, of which
three were used, were of well-seasoned white deal, on the model of
those employed by General Roy, on Hounslow Heath, excepting in
a few minor details. ‘The square brass ferule covering each extre-
mity, was perforated with a hole three-eighths of an inch in diame-
ter; and a brass screw, one-fourth of an inch in diameter, and
nearly two inches long, was passed into the wood through the hole,
without touching the ferule, and ground down perfectly flat. The
head of this screw carried the division which defined the length of
the rod; and it is evident from the arrangement, that it could only
be affected by the expansion of the wood. Eight trestles were con-
structed on the model of General Roy’s, having wood screws and
moveable teak-wood tables ; and the usual equipment of boring-rods
and piquets prepared.

A contrivance suggested by Sir John Herschel for measuring the
space between the divisions on the contiguous ends of the measuring-
rods, when laid in line, was adopted, and found to answer well in
practice; and which obviated the possibility of any mistake in re-
gistering. ‘This consisted in rendering the space a constant quan-
tity, which was effected in the following manner. A couple of
crosses being drawn with a fine point on a slip of mica, about 2°3
inches from each other, and the divided surface turned downwards
to prevent parallax, the crosses were seen through the transparent
mica, like spider lines; and as they were placed, when used, over a
fine line on brass, a neat bisection of the cross was easily obtained,
with the assistance of a common magnifier.

The twenty-feet measuring-rods were compared with the four-feet

Astronomical Society. 527

brass scale belonging to the Observatory. This scale is by Dollond.
It is a thin brass bar, inclosed in a mahogany case, lined with baize,
and was brought to England by Sir John Herschel, on his return
from the Cape, for the purpose of comparison with the Royal Astro-
nomical Society’s standard*. On making the proper reductions for
temperature, the standard measuring-rod was found to exceed 20
feet of the scale by about 1-50th of an inch.

The measurement of the base line was commenced on the 17th of
June, Sir J. Herschel, Lieut. Williams, and Mr. C. Piazzi Smyth,
taking part in the work; but it had only proceeded a short distance,
when it was interrupted by an accident. While Mr. Maclear was
adjusting the 66th rod, a sudden gust of wind blew it and the next
off the trestles, whereby one of them was entirely destroyed, and the
other injured. This accident compelled him to postpone the mea-
surement until November, for before a new rod could be got ready
the winter had set in, and the floods spoiled the le. The author
remarks, that although the contrivances adopted for preventing simi-
lar accidents proved effectual, rods of this description are unfitted
for a windy country like the Cape, being liable to short vibrations,
which no clamping can control.

The measurement was recommenced from the meridian pillar on
the 8th of November, and proceeded without further interruption.
In the preceding June a pig of lead, weighing 56 lbs., was sunk in
the ground, at the end of the 27th rod, and a cross on its surface
adjusted to the plummet. On reaching the 27th rod, in the second
operation, the lead was uncovered, and the plummet fell short of the
cross upon it by nearly half aninch. As the place was frequently
covered with water during the winter, it is probable the lead had
shifted its position.

The measurement was completed in four days. On each day the
rods were compared with the standard, and the proper reductions
made to obtain the length in terms of the standard rod, which also
was corrected to the temperature of 70°, this being the temperature
engraved on the brass scale. The final results gave the distance
between the centre of the meridian pillar and the centre of the gun
= 2919°364 feet.

The angles were measured in the latter part of 1836, while the ap-
paratus for measuring the base was in progress. ‘The instrument
employed for the purpose was the repeating instrument by Dollond,
described in the first volume of the Memoirs. The signals on the
Block-house Battery, the Observatory, and Base-line stations, were
tripods, surmounted by hoops, and covered with white cloth. At
Mrs. De Witt’s house the signal was a circular disc, painted on the
east chimney. ,

On computing the triangles, and making the proper reductions,
the distance between Mrs. De Witt’s chimney and the transit instru-
ment was found to be 17,096 feet, and its distance from the per-

* The comparison has since been made by Sir John Herschel and Mr.
Baily. The mean of sixty-three comparisons gave its length = 47°997083
‘standard inches of the Suciety’s standard yard,

528 Astronomical Society.

pendicular to the meridian 4579°5 feet. Assuming the compression
= -4,, 1 in latitude 33° 56! = 101°739 feet, therefore the differ-
ence in latitude = 45/01; and the latitude of the Observatory being
33° 56! 3/25, that of the chimney is 33° 55'18'"24. The chimney
is south-west of Lacaille’s Observatory, about 120 feet, or 115 on the
meridian, therefore the latitude of his Observatory was 33° 55/17'""11,
Lacaille assumed it to be 33° 55! 15".

The remainder of the paper is devoted to a description of the
heights, distances, and bearings of the mountains about Klyp-Fon-
teyn, which were ascertained with considerable exactness, and a map
constructed, to convey an idea of their form, and probable influence
on the zenith sector. The sector, and the repeating circle, for
taking the angles, were placed on the corn-floor, on Jacobus Cot-
see’s foundation, before the foundation of the granary was discovered;
and, as the place was comparatively convenient, and the influence of
the surrounding masses nearly the same on both, it was considered
unnecessary to remove the instruments. The height of the sector
above the level of the sea was found, by barometrical comparisons,
to be nearly 400 feet.

May 10. ‘Lhe following communications were read :—

Occultations of the Pleiades by the Moon, observed at Ashurst,
March 19, 1839. By Robert Snow, Esq.

Occultations of the Pleiades, observed at the Royal Naval Asylum,
Greenwich, March 19, 1839. By the Rev. George Fisher, A.M.

On the suspected Variability of the Star a Cassiopeia. (Extract
from a Letter from the President, Sir J. F. W. Herschel, to Mr.
Baily, dated Slough, April 28, 1839.)

«« My attention was attracted to the star a Cassiopei@ on the 18th
of October last, by noticing that it was on that night very decidedly
less than the star y of the same constellation, and that in fact y was
then the chief star. On referring to my father’s catalogues*of com-
parative brightness, however, a is found placed above y. It was,
therefore, evident that a change had taken place. On two or three
subsequent nights the fact was verified, and other eyes than my own
were called in to establish its reality. A considerable succession of
cloudy nights intervened before other comparisons were procured ;
and when a favourable opportunity again occurred, viz. on the beau-
tifully clear night of Nov. 12, the order of magnitude was found re-
stored to that assigned by my father, viz. a, y, 3. On the 27th and
28th of Dec. and the 22nd of Jan. 1839, the observations are posi-
tive to this effect.

«Tn this state it remained till I began to suspect some illusion in
the October observations; but, on the 24th inst., being a remarkably
clear and beautiful night, y was again the principal star, and a was
inferior not only to that, but to 6. And so I observed it to be only
about an hour ago. It is true the constellation is now low, but the
stars are so near together that the difference of altitude can by no
means account for the very marked difference in brightness, though
its tendency is certainly in that direction. I should not think of
making this observation the subject of a distinct announcement,

=—,

Astronomical Society. 529

were it not that my own attention is necessarily so much distracted
from these objects as to make me desirous that some other observer
may take up the subject, and verify or disprove the variability of the
star in question; and, if verified, assign the period of change.

«“T may take this opportunity to point out é Orionis as a star of
whose variability I am almost certain.”

Extract of a letter from M. Gautier, Director of the Observatory
at Geneva, to the President, accompanied with the Observations of
Encke’s Comet, made at Geneva in the months of October and No-
vember 1838.

The observations were made with an equatorial of Gambey, having
a telescope by Cauchoix, of 4 inches aperture, and 42 feet in focal
length; and the circles, which are 30 inches in diameter, giving by
means of verniers the arcs to every three seconds. The instrument
required no adjustment during the whole time of the observations,
and the comparison of observations of the best known stars showed
that it possessed great stability and accuracy of division. The me-
thod of observing which was practised does not, however, admit of a
degree of precision comparabie to that which may be attained when
it is possible to employ a wire micrometer illuminated upon a dark
field. On account of the extreme feebleness of the comet’s light,
at least during a part of the observations, a micrometer of this kind
could not be used, and in lieu of it a simple cross was employed,
formed of small thin plates of silver, about 1' of a degree in breadth,
visible without illumination, with a magnifying power of about 25
times. All the observations of the comet and stars were made by
referring each body to this cross, noticing the instant of observation
by a sidereal clock, and reading the position of the telescope by the
verniers of the two circles. The thickness of the plates of the cross
necessarily impairs the precision of the determination, especially for
the declinations; but with a little practice and care, values were
obtained with sufficient exactness, and of about the same precision
as those of comets generally are. ‘The right ascensions were found
by taking the differences of the times of observation and the horary
angle of the equatorial circle, and the declinations by taking the
complement of the polar distances indicated by the declination cir-
cle. The advantages of this method of proceeding are, that the ob-
servations can be multiplied in a short space of time, and that the
best known stars can be taken for a comparison.

Of the three tables which accompany this communication, the
first contains all the observations of the comet, in number 189, cor-
rected only for the error of the clock, which, however, is scarcely of
any consequence, as it effects equally the observations of the comet
and of the stars used for comparison ; the second contains the obser-
vations of the stars, and their comparisons with the mean positions
deduced from the catalogue ; and the third contains the reduction of
the observations of the comet and their comparison with the ephe-
meris of Mr. Bremicker.

In comparing the results of the observations of the comet at Berlin
and Geneva, there is a sufficient agreement on the whole, although

Phil. Mag. 8.3. Vol. 14, No. 92. Suppl. July, 1839. 2 M

530 Astronomical Society.

the positions observed at Geneva are in general a very little advanced
in the sense of the comet’s motion in respect of those observed at
Berlin. M. Gautier thinks the results plainly indicate that a dimi-
nution is required to be made in the value of the mass of Mercury
adopted by M. Bremicker in calculating the effects of the perturba-
tions; and this is also the opinion of Encke: but M. Valz, who
observed the comet at Marseilles, from the 23d of November to the
16th of December, is of a contrary opinion. The observations of
the latter, it may be remarked, confirm entirely a circumstance re-
marked on a former occasion by himself, and also by Struve ; namely,
the contraction of the nebulosity in proportion as the comet ap-
proaches to the sun.

On Ptolemy’s Catalogue of Stars. By Francis Baily, Esq., Vice-
President of the Society.

The catalogue of stars, which goes under Ptolemy’s name, will
always be interesting to the astronomer, as containing the first
record of the state of the heavens. ‘The precise epoch for which it
was formed is not clearly ascertained. Ptolemy himself says, that
it is reduced to the first year of the reign of Antoninus, which cor-
responds to the year a.p. 138; but there is some mistake or con-
fusion, on this point, which has led many persons to believe that
Ptolemy himself did not actually make the observations from which
the catalogue was deduced, but merely reduced, or brought up, a
more ancient catalogue of Hipparchus, by means of an erroneous
precession, to his own time: It is very evident that the longitudes
of all the stars in Ptolemy’s catalogue are avove 1° too great ; but,
from what cause this has arisen, it is not my object here to inquire.
The point to which, in the present view of the case, I am more de-
sirous of directing attention is, how far the existing editions of that
work may be considered as faithful transcripts of the catalogue as
it issued from Ptolemy’s hands.

This important question can only be decided by a careful exami-
nation of various manuscripts, and by comparing the discordant
readings with the actual positions of the stars as determined from
modern observations. Unfortunately the public have not been in
possession of much varied information on this head, the manuscripts
hitherto employed having, until lately, been confined to three only ;
to which two others have been recently added, as I shall presently
explain. But all these are, in many cases, so grossly discordant, that
it would appear, at first sight, almost a hopeless task to reconcile the
different readings that present themselves, or to account for the in-
troduction of so many discrepancies in so small a portion of Ptolemy’s
great astronomical treatise. The five sources of information here
alluded to are,

1st. The Latin translation published by Liechtenstein at Venice,
in 1515; the name of the translator is not known, nor is it stated
whence the manuscript was obtained. The translation, however,
bears internal evidence of having been made from an Arabic manu-
script, and throws great light (as I shall presently show) on the sub-
sequent translations and editions from the Greek manuscripts.

Astronomical Society. 531

2d. The Latin translation made by Trapezuntius (George of Tre-
bizond), and published by Gauricus, also at Venice, in 1528. This
trnslation, from which most of the subsequent editions seem to be
copied, is said to have been made from a copy of a Greek manuscript
which the Abbé Laurentius Bartolinus caused to be made from one
in the Vatican library.

3d. The Greek edition published at Basil, in 1538, by Grynzus.
It is said that he made use of a manuscript that belonged to Regio-
montanus, who had it from the Cardinal Bessarion, and deposited it
in the library of Nuremberg. This, however, has been since doubted ;
and it is not quite certain where the manuscript above mentioned is
now tobe found. ‘This is the more to be regretted, as it is the only
Greek edition extant, except the recent one which I am now about
to mention. It is evidently not the manuscript from which either of
the preceding translations was made. The work is dedicated to our
Henry VIII.

4th. The two cther sources are comprised in the Greek edition
(accompanied by a French translation), published at Paris, in 1818,
by M. Halma. In editing that part of the volume which contains
the catalogue of stars, M. Halma availed himself of two additional
manuscripts which were in the public library of Paris: one of these
he calls the Paris manuscript, which is made the ground-work of his
publication, and the other the Florence manuscript. But some other
sources must have been appealed to, as he occasionally inserts read-
ings which are not to be found in either of these manuscripts, or in
the Basil edition above mentioned.

These several sources of information are all that the public press
affords us in our inquiries relative to this interesting subject ; but
they are lamentably deficient for the purpose. And, as it is pro-*
bable that the public are not fully aware either of the amount or the
frequency of discordance that exists in this matter, I trust I shall not
encroach too much on the patience of the meeting by stating, as
briefly as possible, the result of my own investigations and researches.

Having carefully compared the position of every star, as given in each
of the several copies above alluded to, I have found that out of 1028
stars, of which the catalogue consists, there are about 780 (or more
than three-fourths) of them that are discordant, either in longitude
or latitude; and this, not merely in 10, 20, or 30 minutes, which is
no uncommon difference, but sometimes to an amount involving
whole degrees. ‘That these errors have arisen mostly from the care-
lessness of the copyists, and that they may be partly corrected, in
some cases, by a reference to the true position of the star, lam ready
to admit; but still there are numerous cases where this tentative
method will not avail us, and where we are, after all, left in doubt
as to the identity of the star, or the true reading of the original
numbers.

One source of error I have discovered to be very common, and in
the correction of which I have found the translation from the Arabic
to be of essential service. It is this. The Greek notation for mi-
nutes being denoted by some fractional part of the degree, and such

2M 2

-

id
q

532 Astronomical Society.

fraction being expressed by a dash annexed to the letter which in
common notation denotes the integer, frequent mistakes occur from
the copyist having affixed the dash when it ought not to be inserted,
and from omitting it when it ought to have been annexed. Thus 23°
is correctly denoted by ck y; and 20° 20! (or 20°3) 3 is correctly denoted
by ky’: again 34° is correctly denoted by A 6; “and 30° 15! (or 30°)
is correctly denoted by Xd. Now it is very readily seen that mis-
takes of great moment may be made by the omission or misplacing
of the dash to the second letter: and here it is that the translation
from the Arabic frequently comes in to our aid; for, as their notation
was not liable to the same sort of confusion, we are oftentimes
led to the true reading by areference to their copies. I could point
out numerous instances of this kind; one, however, will be quite
sufficient to illustrate my meaning. The star in Capricornus, the
fourteenth of that constellation in Ptolemy’s catalogue, whose longi-
tude in all the above-mentioned editions, except the first, is said to
be 26°, isin the translation from the Arabic stated to be in longitude
202°, or 20° 10'; which is in fact its more correct value. Andit is
clear that the erroneous translation from the Greek has arisen from
not affixing the dash to the second letter in the expression « s, which
ought to bexs’. Still there remain numerous other cases where this
mode of explication will not avail, and where it would be desirable
that other sources of information should, if possible, be thrown open
to us: and it is on this point, as I have before alluded, that I am
more especially induced to make the present appeal.

Now, it appears that there are several works in this country that
might assist us very materially in the elucidation of this subject.
In the Bodleian library at Oxford there is a Greek manuscript of

»Ptolemy, which was presented by Selden; and there is also, in the
same library, Bernard’s copy of the Basil edition of 1538, wherein
he has copied out all the longitudes and latitudes of the stars in the
catalogue from this same manuscript. In the library of All Souls’
College, it is stated, by Fabricius, that there is the manuscript of a
Latin translation from the Arabic; and I understand that there are
also manuscript Latin translations from the Arabic at New College
and at Magdalen College. There is also a manuscript commentary
in Persian, belonging to St. John’s College. In the library of the
Archbishop of Canterbury at Lambeth there is also a Greek manu-
script of Ptolemy. In the library of the British Museum there is an
Arabic manuscript, of the date 1218; but I have not been able to
find there any Greek copy.

It is evident, therefore, that we have in this country several sources
of original information, of which we might avail ourselves, to render
the catalogue of Ptolemy more perfect than it is; and, lest it might
be supposed that this would be an useless labour at the present day,
when the state of the heavens is so much better known, I would re-
mark that it is on this very account that more accurate information
is required; since we now know that many minute and gradual
changes are going on, which were not suspected or thought of in
former times, and which are only perceptible after a lapse of many

Astronomical Society. 533

centuries. Thus Sirius is described in all the original documents
that I have seen, as izdxppos, subruffa, reddish ; whereas, at the pre-~
sent day, it isremarkable for its freedom from all colour. Now, this
is a point on which Ptolemy could not well be mistaken. Again, a
star of the feurth magnitude (the seventeenth in the constellation of
Eridanus) is clearly laid down by Ptolemy, but cannot now be found ;
and there are some others, of smaller magnitude, that cannot be
identified, according to the positions given in the present editions of
the catalogue. But whether these bodies have vanished wholly from
our sight, or have been erroneously copied from the original observa-
tions, can only be satisfactorily explained (if, indeed, they ever can
be) by reference to other authorities. It is needless, however, to
dwell further on so obvious a principle.

I had taken the liberty of suggesting to the late Professor Rigaud
(a name ever dear to the lovers of astronomy, and more especially
to those engaged in historical researches in that science) the pro-
priety of requesting the University of Oxford to print the catalogue
of Ptolemy, from the Greek mauuscript in their possession: a re-
quest which, I understand, was favourably received. We are all
sensible of the obligations under which we lie to the University of
Oxford, for its noble and spirited conduct, on former occasions, in
publishing the works of some of the best ancient authors on scien-
tific subjects, which otherwise might never have seen the light; and
certainly not in so splendid a dress. Witness the works of Euclid,
Apollonius, Archimedes, &c. ; and in more recent times, a continu-
auce of the same liberal and enlightened course on various occa-
sions, in the publication of works that reflect honour and credit on
the University, and from which they can never expect to reap any
pecuniary benefit.

Since that application, however, was made, the information re-
lative to the additional manuscripts above-mentioned has been ob-
tained; and it may now become a question whether it may not be
presumed that a more accurate copy of Ptolemy’s catalogue is more
likely to be deduced from a careful collation of all the manuscripts
within our reach, compared with the several original editions and
translations above alluded to, than from the printing and publica-
tion of a single Greek manuscript. Should a plan of this kind be
attempted, I would propose that a few copies of the Basil edition of
15388 be reprinted (for I fear that the original work is too scarce to
be met with in sufficient quantity for this purpose), and distributed
amongst those persons who would each undertake to collate such
copy with some one or other of the manuscripts in the several
archives above-mentioned. This would be no great task or labour
to those who feel an interest in the cause, and who are zealous in
the promotion of science. Copies even might be sent abroad, to
some of our foreign members, residing in places where original
manuscripts are known to exist; and who might thus add to the
common stock of information. But, whichever course may be
adopted, I trust there is no difference of opinion as to the propriety
of taking some steps relative to this matter: and I hope that what

534 Cambridge Philosophical Society.

I have here stated may induce others to join in carrying so desirable
an object into execution.

Mr. Baily stated to the meeting that further accounts had been
received from America, relative to the annular eclipse of the sun on
the 18th of September last. Professors Henry and Alexander ob-
served it at Princetown College, New Jersey. About eighteen seconds
before the formation of the ring, the moon’s limb became brightly
illuminated. An appearance similar to a row of beads was regarded
as the formation of the ring: the drops continued for a second or
two. Professor Alexander remarks, that the luminous arch round
the moon’s dark limb, and the brush of light, were only partially
visible in his 4-feet Fraunhofer, with a yellow screen-glass, having a
slight tinge of green: but he saw them distinctly in his 3}-feet
Dollond with a red screen-glass, for about four minutes after the
rupture of the ring: whence it is inferred that the appearance of the
beads of light and the dark lines frequently noticed, may be com-
pletely modified by the colour, and consequently the absorbing power
of the screen-glass through which they are observed.

It was noticed by most of the observers, that before the formation
and after the rupture of the ring, the edge of the moon of the sun
was distinctly visible, and illuminated for some distance within the
moon’s surface.

CAMBRIDGE PHILOSOPHICAL SOCIETY.

April 29, 1839.—A meeting of this Society was held on Monday
evening, Professor Cumming, one of the Vice-Presidents, being in
the chair. Mr. Gregory exhibited various photogenic drawings, and
described the process by which they were prepared. Professor
Sedgwick gave an account, illustrated by various drawings, of the
geological structure of Cornwall, according to the new views re-
specting the place of its rocks in the order of the British strata to
which he and Mr. Murchison have recently been led.

May 6.—A meeting of this Society was held on Monday evening,
Dr. Graham, the President, bemg in the chair. Professor Miller
made a communication on the Theory of Halos, with particular .re-
ference to Fraunhofer’s views on that subject. Mr. Green read a
note, additional to a former memoir, on the Reflection and Refrac-
tion of Light. Mr. Gregory read a paper on Chemical Classifica-
tion.

May 20.—A meeting of this Society was held on Monday even-
ing, Dr. Clark inthe chair. Mr. Ansted made a communication on
the Tertiary Formations of Switzerland. Mr. Green read a memoir
on the motion of light through crystallized media. Mr. Whewell
read a note respecting the working of his Anemometer since his
memoir on that subject read May 1, 1837. The Anemometer had
since that time been in action at the Society’s house, and at the
Cambridge Observatory ; but in consequence of the instruments be-
ng frequently repaired and improved, the observations were fre-

American Philosophical Society. 535

quently interrupted. The observations for the months of July and
August 1838 were, however, represented by comparative diagrams,
which were exhibited to the Society. From this comparison it ap-
peared, that the form of the line representing the course of the wind
as registered by the instrument at the two places is nearly identical,
thus proving the consistency of different instruments of this con-
struction with one another. ‘The scale of the two instruments ap-
peared to be different, nearly in the ratio of 2 to 1, but no direct
comparison of the scales had been attempted. It was stated also,
that, during 1837 and 1838, observations had been made with Mr.
Whewell’'s Anemometer at Edinburgh by Mr. Rankine, and ex-
pressed in a diagram (according to the method recommended by
Mr. Whewell) in the 14th volume of the Edinburgh Transactions.
Observations with this instrument have also been made at Plymouth,
and reduced by Mr. Southwood (of St. Peter’s College), by whom
also the diagrams for Cambridge were constructed. Mr. Whewell
stated, in conclusion, that there is every reason to believe, from the
results hitherto obtained, that if any person with sufficient leisure
were to take up this subject, it will reward him by leading to the
knowledge of important meteorological facts and laws.

AMERICAN PHILOSOPHICAL SOCIETY.

July 20, 1838.—The Committee appointed on the communication
of Dr. John Locke of Cincinnati, read at the last meeting, [consisting
of Messrs. Peter S. Duponceau, R. M. Patterson, and J. Saxton,]
made the following report, which was adopted.

“ The Committee to whom was referred the communication of
Professor John Locke, of Cincinnati, report, that it gives the details
of a series of experiments, made for the purpose of determining the
magnetic intensity and dip for certain positions in Ohio. For these
experiments he had furnished himself in London with the best ap-
paratus, and had vibrated there two needles of the form recom-
mended by Hansteen, and one in the form of a small flat bar. Five
months afterwards, namely, on the 17th of January, 1838, he again
vibrated these needles at Cincinnati, and found the ratio of hori-
zontal intensity at the former place to that at the latter, as follows :
by needle, No. 1, as 1 to 171624; by needle, No. 2, as 11639; by
No. 3, as 1 to 12037. Of these results the author prefers the last ;
inasmuch as the magnetism of needles is liable to decrease, but not
to increase.

“On the 20th of August, 1837, he made experiments with his
dipping needle, to determine the dip at Westbourn Green, near
London, the mean of which gives 69° 23!"3.

“ On the 26th of November, 1837, the mean of a series of ex-
periments made at Cincinnati, in lat. 39° 6'N., and long. 84° 27!
W., gave the dip = 70° 45°75.

« At Dayton, Ohio, in lat. 39° 44! N., and long. 84° 11' W., the
dip was found to be 71° 22'-75 on the 26th of March 1838.

«« At Springfield, Ohio, in lat. 59° 53! N., and long. 83° 46' W.,
the dip was found on the 29th of March 1838, to be 71° 27375.

536 American Philosophical Society.

« At Urbana, lat. 40° 03! N., long. 83° 44! W., March 30, 1838,
ip was found = 71° 29'-94.

ane Columbus, the seat of government of Ohio, lat. 39° 57! N.,
long. 83° W., April 3, 1838, the dip was found = 71° 04''875.

«©The interest of this paper is much increased by the circum-
stance that no accurate experiments on the intensity and dip of the
needle have heretofore been made in the United States, west of the

ny mountaims.

a Gomaatine conclude their report, by recommending that
Professor Locke’s communication be printed in the Society’s ‘I'rans-
ae 21, 1838.—The Committee on the solar eclipse of the 18th
of September, made a report in part, comprising the observations
made at Philadelphia, the principal results of which are as follows :

The observations made at Philadelphia are fifteen in number.
A list of observers, telescopes, &c. is given in the following table.
The correction in the third column is to be added algebraically to
the latitude of the place of observation, to obtain that of the State-
House, +39° 56' 58”. The correction in the fourth column is
likewise to be added to the local longitude in time, to obtain that of
the State-House, —550™ 39°25.

S58 | 228) % g ls
S38 | 228 | By a | Peed ei g
No. Observers. S23 325 rs as Description. 5 ES
Bes | SES | o7 2 | aha

“fl

Teh) eealls;.ca ct, 3-12 —70°0|-+1-70} 2°5 | Unknown. Spy-glass |smoked| 15
2.| Wm. Penn Cresson... |— 1°8)-+5'20| 2:5 Jones. |Achromatic) red 30
3.| Prof. W. R. Johnson |— 1°8)+45:20) 3:5) Dollond.. do. do. {100
4.| George M. Justice... |—10.0|+-2°86| 2°5 | Jones. Gregorian| do. | 80
5.| E. O. Kendall .. .. | —10°0|+2°86| 2°5 Plossl. Dialytic | green | 50
6.| Joseph Knox ...... —21°0}+1'39| 3°5 | Dollond. |Achromatic| red | 80
7.| Isaiah Lukens......... — 9'0|+0°86/1:8| Plossl. Dialytic |yellow| 20
8.| Thomas M‘Euen...... + 0'4|)+2°33| 2:5} Dollond. |Achromatic| red | 60
9. | Prof. Roswell Park — 6°5/+1°30| 2°5 do. Gregorian | do. | 50
10.| Dr. R. M. Patterson |— 1'1/+1°20} 5:0 do. Equatorial] do. |100
1l.| W.H. C. Riggs...... + 0°4|+2°33 | 3°5 do. Achromatic] do. | 50
12.| Samuel Sellers ...... — 7°5|-+0:05|2°5| Jones. do. do. | 40
13.} Tobias Wagner ...... — 10:0 |}+-2°86 | 3:5 | Dollond. do. do. | 80
14.| Seares C. Walker ... |—10°0|+2°86| 5:°0| Tulley. do. do, |100
15.| William Young ..... +21:0)—1:39| 7:0 | Hilcomb. |Herschelian} do, |200

A. Beginning. Professor Johnson noticed dark indentations for
eight seconds after the first disturbance of the limb.

B. Arch of faint light, with speck or brush in centre, round the
moon’s limb beyond the cusps ; brush or blaze in centre, between
cusps, extending outwards about two digits. One cusp broken at
end presenting a bright bead.

C. Arch of light much increased in brightness, the brush or
blaze, at first in the centre, now extends from cusp to cusp; radia-

—

American Philosophical Society. 537

tion outwards, nearly three digits; cusps distant 30° on sun’s limb,
a broken point or bead at each end. This phase noted as that of
the formation of the ring by Nos. 1, 2, 3,4, and 11.

D. Formation of ring or instant of osculation of limbs. This
phase noticed as the approach of two sharp well-defined points to
a contact, by Nos. 5, and 15. It was observed at the instant when
the cusps, apparently 20° of the sun’s limb apart, suddenly united
by the extension of four or five luminous beads, or rounded portions
of the sun’s disc, by Nos. 3, 4, 8, 9, 10, 11, 13, and 14.

E. Omitted in the table. This letter refers to the time when
the dark lines, described by Van Swinden and Baily, should have
appeared. ‘They were not seen by any observer, though carefully
searched for.

F. Perfect ring, the beads of light having united, or run into each
other suddenly.

G. Counterpart of E, not observed though looked for.

H. Rupture of ring, counterpart of D. Took place at a point
and so noted by all the observers.

I. Appearance of beads, five or six in number, extending from
cusp to cusp.

K. Counterpart of C, in every respect.

L. Counterpart of appearance just preceding C. Brush or blaze
of light, narrowed down to a small space, 3° or 4° on the moon’s
border, extending outwards 25 digits ; cusps still broken as seen by
most of the observers. Nos. 5 and 15, however, saw no irregularity
of cusps, no beads of light.

M. Final disappearance of arch of faint light, with brush of light
extending beyond the middle, having previously become very faint.
This phenomenon observed with great care and certainty by No. 10.

Phases observed, in mean times of the Places of Observation.

ate Delp. re) et | |. (ow. | eo, | P.
No.jh. m./h. m./h.m./h.m.jh. m./h.m.h,m,h.m.'. m.'h.m.{/h.m./h. m./h. m.
3 13\4 30/4 31/4 $1|4 31/4 35/4 55/4 35/4 35.4 41/5 4515 4555 45
S. Ss.
15 3°9 284
ais, —70 7S esa |*-Se 5. | S
a 11097 » |10°5| s. 115°5 12395 127°5|29°0) 2.0 | woe | 421122
4.| 7°4 GiGi Bilis 127 =Sh lias sill Fonsi brace, ilacctll eee (LIPS
Pee eee ea ally ames) d, 22 Hl DAM ce on || tacera| ewesttili-aae: Meee eee O
6. {128
alencpiteca | eet |2er | ccc | cos | 20s, LG0'e
MAOH eset eee (MOM ieee: (2981) saemiiccer |p moslt|iteee |e
9. s. LOT ie me | SOM 2s el nean |e sea |e Se Ss.
A SOs ke des [LOT wee [GOR ace htsse>') Kon 23°1| ... {16°1 {19:1
Mee 73 1GO!2 | ZAjVGS| ccs |2O%4| 0. |BO'D| oo» |. one | con |, 27'S
Meee OO) tera | ade (LOO!) aco GACO!) coeliac | apa | vee | con [LOO
a, | Or rs
14.| 5°6\36°7| ... |15°6 23°0 |28:0 29°5 }37°0 |42'0)| ... |10°0 |13°0|16°0
Te Pett cfAl UNO tise, |) ric Aorexn, 8 Olioua Vapedtiratss Ee

* Doubtful.

538 American Philosophical Society.

N. Appearance of dark lines extending into the sun’s disc, no-
ticed by Nos. 3,4, 10, and 14. The time noted by Nos. 3 and 14,
as the end of the eclipse.

O. End of Eclipse, inferred by each observer from his notes. _

P. Final disappearance of the dark lines, the sun’s disc having
resumed its natural shape, Nos. 3, 4, 10, and 14, inferred the time
of O as at some instant intermediate between N. and P. The time
of external contact difficult to determine on account of this irregu-
larity.

For the convenience of computors the local times above given
have been reduced to their corresponding value for the State-House
by E.O. Kendall, by means of his formule, in vol. xx. of the Journal
of the Franklin Institute, p. 125, which gives the following values
for the variation of the local times of the several phases, for a small
variation of terrestrial latitude or longitude as follows :

ats Beginning. Ring. End.

Variation for + or north | __0-0397 —0-0382 —0-0343

fear. lat.» owls). "vis br

Variation for + or east1S|] _ , 4. F :

of terr. long. in time. . } eee ae ee

The means of his results for the State-House giving to each ob-

servation its proper weight in mean time of the State-House, are,

Beginning........... ay 8. 0h BP FE 10"OE
Formation of ring .......... 4 31 18°76
Raptureof ring). oF) Jat en 4 SR IST 85
Gee oe Te eae aan 5 45 15°46
Duration of eclipse .......... 2 32 5:40
Duration of ring ............ O 4 12°59

Dr. Patterson read a paper by Professor Charles Bonnycastle, of
the University of Virginia, containing ‘‘ Notes of Experiments made
August 22 to 25, 1838, with the view of determining the depth of
the Sea by the Echo.”

This paper, which was not offered for publication in the Society’s
Transactions, states that the generally received notions in regard to
the intensity of sound in water, and the distance to which it is con-
veyed, had suggested to Mr. Bonnycastle some years ago, the idea
that an audible echo might be returned from the bottom of the sea,
and the depth be thus ascertained from the known velocity of sound
in water. The probability of this view was deemed at least sufhi-
cient to justify an experiment; and accordingly the Navy Com-
missioners authorized the construction of the necessary apparatus,
and Captain Gedney, of the U.S. brig Washington, attached to the
coast survey, volunteered his services, and the use of his vessel, and
authority to this effect was liberally granted by the Secretary of
the Treasury, Mr. Woodbury.

The apparatus, which is fully described in Mr. Bonnycastle’s
paper, consisted first of a petard or chamber of cast iron 25 inches
in diameter, and 51 inches long, with suitable arrangements for
firing gunpowder in it under water; secondly, of a tin tube, 8 feet
long and 14 inch in diameter, terminated at one end by a conical

American Philosophical Society. 539

trumpet-mouth, of which the diameter of the base was 20 inches,
and the height of the axis 10 inches; thirdly, of a very sensible
instrument for measuring small intervals of time, made by J. Mon-
tandon, of Washington, and which was capable of indicating the
sixtieth part of a second. Besides these, an apparatus for hearing
was roughly made on board the vessel, in imitation of that used
by Colladon in the Lake of Geneva, and consisted of a stove-
pipe, 44 inches in diameter, closed at one end and capable of being
plunged four feet in the water. The ship’s bell was also unhung,
and an arrangement made for ringing it under water.

On the 22nd of August, the brig left New York, and in the evening
the experiments were commenced. In these, Mr. Bonnycastle was
assisted by the commander and officers of the vessel, and by Dr.
Robert M. Patterson, who had been invited to make one of the
party.

In the first experiments, the beil was plunged about a fathom
under water and kept ringing, while the operation of the two hear-
ing instruments was tested at the distance of about a quarter of a
mile. Both instruments performed less perfectly than was ex-
pected, the noise of the waves greatly interfering, in both with
the powers of hearing. In the trumpet-shaped apparatus, the ring-
ing of the metal, from the blow of the waves, was partly guarded
against by a wooden casing; but, as it was open at both ends, the
oscillation of the water in the tube was found to be a still greater
inconvenience, so that the sound of the bell was better heard with
the cylindrical tube. At the distance of a quarter of amile, this
sound was a sharp tap, about the loudness of that occasioned by
the striking the back of a penknife against an iron wire; at the
distance of a mile the sound was no longer audible.

In the second experiments, the mouth of the cone in the trumpet
apparatus was closed with a plate of thick tin, and both instruments
were protected by a parcelling of old canvas and rope-yarn, at the
part in contact with the surface of the water. In these experiments
the cone was placed at right angles to the stem, and the mouth di-
rected towards the sound. The distances were measured by the in-
terval elapsed between the observed flash and report of a pistol. At
the distance of 1400 feet, the conical instrument was found consi-
derably superior to the cylindrical, and at greater distances the su-
periority became so decided, that the latter was abandoned in all
subsequent experiments. At the distance of 5270 feet, the bell was
heard with such distinctness as left no doubt that it could have been
heard half a mile further.

The sounds are stated in the paper to have been less intense than
those in air, and seemed to be conveyed to less distances, The
character of the sound was also wholly changed, and, from other
experiments, it appeared that the blow of a watchmaker’s hammer
against a small bar of iron gave the same sharp tick as a heavy
blow against the large ship’s bell. It is well known that Franklin
heard the sound of two stones struck together under water at half a
mile distance ; yet two of the boat’s crew, who plunged their heads

540 American Philosophical Society.

below the water, when at a somewhat less distance from the bell,
were unable to hear its sound.

On the 24th of August, the vessel having proceeded to the Gulf-
stream, experiments were made with the view for which the voyage
was undertaken; that is, to ascertain whether an echo would be
returned through water from the bottom of the sea. Some diffi-
culties were at first presented in exploding the gun under water,
but these were at length overcome. The hearing-tube was bal-
lasted so as to sink vertically in the water. ‘The observers then
went with this instrument to a distance of about 150 yards from the
vessel, and the petard was lowered over the stern, about three
fathoms under water, and fired. The sound of the explosion, as
heard by Mr. Bonnycastle, was two sharp distinct taps, at an in-
terval of about one-third of a second. Two sounds with the same
interval were also clearly heard on board the brig; but the charac-
ter of the sounds was different, and each was accompanied by a
slight shock. Supposing the second sound to be the echo of the
first from the bottom of the sea, the depth should have been about
160 fathoms.

To ascertain the real depth, the sounding was made by the or-
dinary method, but with a lead of 75 pounds weight; and bottom
was distinctly felt at 550 fathoms, or five furlongs. The second
sound could not, therefore, have been the echo of the first; and
this was proved on the following day, by repeating the experiment
in four fathoms water, when the double sound was heard as before,
and with the same interval.

The conclusion from these experiments is, either that an echo
cannot be heard from the bottom of the sea, or that some more ef-
fectual means of producing it must be employed.

Oct. 5, 1838.—The Committee on the solar eclipse of the 18th of
September, made a further Report in part.

This portion of the report embraced the observations made in the
vicinity of Philadelphia, of which the following are the principal
results, arranged in the order in which they were received, and with
one exception, in mean time of the place of observation ; the longi-
tudes being reckoned from Greenwich.

No. 16. by Robert Treat Paine, Esq., at the west front of the
Capitol, Washington. Latitude 38° 53! 23", as determined by Mr.
Paine with his ‘lroughton’s sextant. Longitude 5h. 8m. 8s. west.
With 34 feet equatorial, green screen glass. Time by three chrono-
meters, regulated by eastern and western altitudes of sun and stars
with his Troughton’s sextant.

BepwnwiA ge 6!) ie ike ae ee 3.6™. 958
Formation of ring.........- 4 24 28°15
Rupture ofring’ .05:./5js0'. 3 4 30 18°55
Bad seiiad ose eb toads 5 39 54°89
Duration of eclipse .......+. 2 33 45°31
Do. GEIR ate siees os Go's 0 5 50°40

«The ring formed instantaneously, and broke nearly so. No
beads were seen, nor the dark lines mentioned by Mr. Baily, nor

American Philosophical Society. 541

the light round the moon, although all were looked for. No dis-
tortion of the moon’s limb could be seen, and the cusps of the sun,
before the ring formed, were as sharp as needles.”

No. 17, by Lieut. Gilliss, U.S.N., at the Marine Observatory,
Washington City, N. 8’, W. 008° in time from the Capitol, with
a 34 feet achromatic, green screen glass, power 50. Astronomical
clock regulated by a five feet transit instrument.

ELT (aly is Al 35 6™10%4
Formation of ring .......... 4 24 28-4
Huptire or ring. EON), ye 8 189
12/2 apeinche acento sarhae deme aa anaes 5 39 56°4
Duration of eclipse .......... 2 33 46°0

PP Ot eiMes eer ofa! Ya ce re he O) ESOS

« At beginning of eclipse, limbs sharp and well defined. The
same at formation and rupture of the ring, only in the former the
light seemed to flash round the moon’s limb.” ‘Two detached arched
portions of the ring were seen separated from the cusps, ‘ while
the space between presented points of light (beads) only.”

No. 18, by Prof. Elias Lumis, at the Observatory of the Western
Reserve College, Ohio. Latitude 41° 14’ 42!" N. Longitude
55 25™ 35° W. With a five-feet equatorial, mounted on a stone
pier under a revolving dome, with yellow screen glass, power 150
nearly. Astronomical clock regulated by a 30-inch transit circle by
Simms.

Beginning 14> 27™ 26°75 sidereal time.
Other phases lost by clouds.

Nos. 19 and 20, by J. Gummere and his son S. J. Gummere, at
the Haverford School Observatory, Chester County, Pa. Latitude
41° 1'12" N. Longitude 5" 1" 165 W. With two 34 feet tele-
scopes by Tulley, with red screen glasses, power 75 nearly. As-
tronomical clock regulated by a Dollond’s portable transit instru-
ment.

Beemnnie ors 2. Ses 0) 22\- Sham ee
Formation of ring .......... 4 30 29°2
upente OP S10, saa se ee es es 4 34 44°8
PI Poe eats Nee chee ee 5 44 28°7
Duration of eclipse.......... 2 32.11°5
IGE GE SUEY Ws 012 3)2 2% ate cuit O 4 15°6

Arch of faint light with brush in centre, seen before the forma.
tion of the ring. Arch seen after rupture, brush of light not recol-
lected. Formation and rupture of the ring, by broken portions of the
sun’s border, several in number, not round like beads, but arched
portions of the ring. These continued several seconds, and then
suddenly united in the first instance, and separated in the last,
without, however, exhibiting the dark lines figured by Baily.

Nos. 21 and 22, by Charles Wister and his son Caspar E. Wister,
at the Observatory of the former, Germantown. Latitude 40° 1/59",
Longitude 2*7 in time west of the State House, with 24 and 2
feet Gregorian reflectors. Astronomical clock regulated by a 3 feet
transit instrument.

542 Intelligence and Miscellaneous Articles.

C. Wister. c. E. Wister.
Beginning .......... 35 12™55%4 3 12™54%4
Formation of ring.... 4 31 9°4 431 8°4
Rupture of ring...... 4 35 18°4 4 35 18-4
End... “avers iy (D464 5 45 7°4
Duration of eclipse. . 2 32 13°0 2 32 13°0
Def TINE: t 2.4 5ohae ote 0. 4,-19"0 0 4 10°0

“The lucid points and dark intervening spaces corresponded
closely to Baily’s description,”

No. 23, by John Griscom. Latitude 9-7 N. Longitude 0°3* in
time west of the Observatory of Haverford School. With a 3} feet
Dollond achromatic, power 80.

ReRIRBIEE 6.) fi ye vidi ty oes 35 12™1856
Formation of ring ...........- 4 30 31°6
Rupture of ring (not reported)

ht re ee eee 5 44 26°6
Duration of eclipse ...........- 2.32 .8°6

Do. of ring (not reported).

No. 24, by Prof. James Hamilton of Burlington, New Jersey.
Latitude 40° 5’ 10" N. 69°15 in time east of State House, Phila-
delphia. With a five feet achromatic, power 80, clock regulated
by equal altitudes with a sextant.

Beginning....... i Serna lorghee oti 35 14" 238-7
Formationyor rig! yrs... 2s. 2 = 4 32 32°6
Raphunevof ring /2) tl ac. bah sv 4 36 19°6
Ea Wide. Paweeks 18 Jaye men 5 46 8°5
Duration of eclipse... ssscis5J5 o's 2 31 44°8
Daxqhringy hoes sles wae 0 3 47°0

“‘ The phases of the ring are the perfect formation and perfect
rupture, without reference to beads. No dark lines seen.”

LXXIII. Intelligence and Miscellaneous Articles.

PROCEEDINGS OF THE COMMITTEE OF COMMERCE AND AGRI-
CULTURE OF THE ROYAL ASIATIC SOCIETY OF GREAT BRITAIN
AND IRELAND.

HE first Number of the Proceedings of this Committee has ap-

peared, and the valuable information whichthis pamphlet contains,
fully bears out the expectations which its formation justified us in
entertaining. ‘The reports of this Committee cannot fail to possess
high interest for the merchant and manufacturer, as pointing out the
much neglected resources of our extensive Indian possessions, as
indicating new sources of long-known articles of commerce, and de-
scribing new substances well adapted as substitutes for many of those
well known, and at present imported from foreign countries.

The Proceedings contain abstracts of a series of papers on various
important subjects ; amongst which are cotton, rice, silk, caoutchouc,
tanning substances, dye-stuffs, medicines, oils, and oil-seeds ; these
are principally by Dr. Royle, the Secretary of the Committee; Mr.

Intelligence and Miscellaneous Articles. 543

E. Solly, Jun., their Chemical Analyser ; Mr. Southey ; Mr. Gibson,
of the Bombay Medical Establishment ; Mr. Heath, of the Indian
Iron and Steel Company ; Mr. Hughes, of Tinnivelly ; Mr. Sievier,
Superintending Manager of the London Caoutchouc Company ; Drs.
Cantor, Lush, and Geddes, &c.

We look forward with great interest to the publication entire of
the papers which have been communicated to this Committee; and
we hope that it will meet with that encouragement which the im-
portance of its objects entitles it to expect.

SEPARATION OF ETHYLE (ETHULE, ETHEREUM, = 4¢ +5 H.)
BY C. LOWIG.

Small pieces of potassium are placed in a glass tube 3 to 5 lines
wide containing chloride of ethyle; a powerful action ensues, and
the metal becomes covered with a white crust, which should be
broken up so as to cause a fresh metallic surface to be exposed to
the action of the fluid. The mixture soon begins to boil: a tube
bent at right angles should be fixed in the mouth of the large one,
to connect it with a receiver kept cool by a freezing mixture ;
chloride of ethyle unmixed with any other product distils over.
Ultimately, if sufficient chloride were present, all the potassium be-
comes converted into the white crust; if this be exposed to heat, it
_ gives off an inflammable gas, becomes black, and by exposure to air
undergoes rapid combustion.

When the white crust is placed in water it dissolves, hydrogen
gas being evolved; on agitating the watery solution with ether,
and decanting the ethereal solution, a volatile, oily fluid is obtained
by evaporating it in vacuo at a low temperature. This fluid burns
with a vivid flame, has a peculiar soap-like odour, ‘and very acrid
taste.

On submitting the white powder obtained by the action of potas-
sium on chloride of ethyle to analysis by combustion with oxide of
copper, it yields,

0°870 carbonic acid = 0°2405 carbon,

0°450 water = 0°0500 hydrogen ;
and 100 parts will consequently consist of
(i i 82°79
: Br yaren: =. ssid. 1) LY Bh 100°
or, 4 atoms carbon 305°74 4 atoms carbon 24
10 atoms hydrogen 62°40 > S atoms hydrogen 5
atoms of ethyle 368:14 atoms of ethyle 29
equivalent to 83°05 carbon,
_ 16°95 hygrogen,
100°

which approaches very closely to the result of experiment.

From these experiments Léwig concludes, that by the action of
potassium on chloride of ethyle, chloride and ethylide of potassium
(Aethylkalium) are formed, the latter combination being decomposed

5 Ad Intelligence and Miscellaneous Articles.

by the action of water, setting free the ethyle, either pure or as an
hydrate. Lowig further remarks, that a combination of ethyle with
sulphur, analogous to that with potassium, exists, and may be pre-
pared by adding an alcoholic solution of sulphuret of potassium to
chloride of ethyle; in a short time chloride of potassium is de-
posited, and the sulphureous combination left in solution.
Poggendorff, Annalen, 45, p. 347. Oct. 1838.

SEPARATION OF PHOSPHORUS FROM ITS OXIDE. BY M.
BOTTGER.

All chemists who have prepared oxide of phosphorus by the usual
method of burning phosphorus under water by a current of oxygen
gas, are aware that a considerable quantity of free phosphorus ad-
heres mechanically to the oxide thus obtained; and that it is re-
~ moved with extreme difficulty, however cautiously the distillation
may be conducted. ‘This difficulty is derived from the circum-
stances, that if a current of gas free from oxygen be not continually
passed into the distillatory apparatus, and the heat be not carefully
regulated, the oxide of phosphorus decomposes very readily, while
too low a temperature does not completely expel the phosphorus.
Some good methods of obtaining oxide of phosphorus have lately
been published, among others, that of M. Leverrier, by chloride of
phosphorus, which leaves nothing to be wished for; but M. Bottger
thinks that his process is probably more easy of execution. He has
found that sulphuret of carbon is of all known bodies the best sol-
vent of phosphorus; in fact, contrary to the generally admitted
opinion, that this substance can dissolve only 8 parts of phospho-
rus, he has proved that it can dissolve 20 at a mean temperature,
whereas the oxide of phosphorus is not at all acted upon by it; the
method which he proposes is the following: put the impure oxide
of phosphorus, obtained by combustion, intoa large bottle, pour sul-
phuret of carbon upon it, with an equal measure of absolute alco-
hol: cork the bottle, and shake it well for about a minute, then
allow the oxide to subside, and pour off the phosphorized liquor ; re-
peat this operation with a fresh portion of the sulphuret and alcohol,
and then put the oxide of phosphorus on a filter, and wash it first
with alcohol and then with water; after this dry it by exposure to
the air, or what is still better under a receiver over sulphuric acid.

The product thus obtained appears to possess all the properties of
pure oxide of phosphorus; when heated in the air, it resists com-
bustion at a high temperature. When mixed with chlorate of
potash it produces a strongly detonating powder, violent explosion
taking place even during mixture, without employing any consider-
able pressure. It is desirable to determine by analysis whether the
oxide obtained by this process is similar to the yellow oxide procu-
red by that of M. Leverrier. According to Pelouze the oxide obtained
by combustion and purified by distillation consists of 3 ats. phos-
phorus + 1 at. oxygen, while that procured by the decomposition
of the chloride consists, according to Leverrier, of 4 ats. phosphorus
+ 1 at. oxygen.—Journ. de Phar. Feb, 1839.

INDEX

or

INDEX To

or

Woh XTe

ee

Axssene (M. A.) on the influence
of native magnesia on the germination
and fructification of vegetables, 238.

Acetone, on the action of, on the bi-
chloride of platinum, 84,

Acids :—aconitic, 76; alloxanic, 232;
carbonic, equilibrium of, in the atmo-
sphere, and its influence on vegetation,
365; chloro-chromic, 230; cyanoxalic,
232; erythric, 231; hydrocyanic, 186;
mesoxalic, 253; mykomelinic, 234 ;
nitric, products obtained by the reac-
tion of, on alcohol, 324; oxalhydric,
329; oxaluric, 235; parabanic, 234;
selenic, preparation of, 396 ; uric, 231.

ZEther, hyponitrous preparation of, 326.

, valerianic, on the composition and
properties of, 74.

ZEthers, on the theory of the, 163.

Air and light, effects of, in restoring
faded colours, 416.

Airy (G. B.), a catalogue of 726 stars,
reduced to 1830, 228; experiments on
iron-built ships for the purpose of dis-
covering a correction for the deviation
of the compass produced by the iron,
A577,

Alcohol, action of chloride of zinc on,
156 ; observations on some of the pro-
ducts obtained by the reaction of ni-
tric acid on, 324.

Aldehyd, production of, 329.

Alloxan, properties of, 231.

Amilen, composition of, 156.

Ammonia, action of the sulphate of, on
glass, 75; use of, in fixing photo-
graphs, 474; oxalurate of, 235.

Amygdalin, decomposition of, by emulsin,
414,

Analyses:—of fire damp from coal mines,
1; of native iron, 32; of valerianic
ether, 74; of fossil copal, 87; of or-
ganic mineral substances, 88 ; of be-
rengelite, 89; of middletonite, 93; of
guaquilite, 93; of naphthalin, 152;
of wax, 155; of the oil of potatoes,
156; of a mineral water, 301 ; of re-
sins, 340; of rose mica lepidolite, 393;
of perikline, 397; of oligoclas, 398;
of delvauxene, 474; of idocrase, 476.

Analytic crystals, observations on, 19.

Third Series. Vol. 14.No.92. July 1839.

Arsenic, on the separation of, from cop-
per, 78.

Arteries, on a remarkable property of,
174.

Asia Minor, geology of a part of, 455.

Astronomical observations made at Wilna
in 1835, 67.

refractions, on the theory of, 276,

342.

Society, proceedings of, 67, 226,
314, 521.

Astronomy :—on the shooting stars of
Nov. 12, 1838, 39; astronomical ob-
servations made at Wilnain 1835, 67;
determination of the parallax of Cygni
(61), 68; on the passage of the moon
across the Pleiades in 1839, 177 ; a ca-
talogue of 726 stars reduced to 1830,
228; on the theory of astronomical re-
fractions, 276, 342; ona curious ac-
count of the comet of 1472, 260; on
the annular eclipse of the sun, May 15,
1836, 229; on the parallax of a Cen-
tauri, 316 ; method of determining the
longitude by moon-culminating stars,
521; on the suspected variability of
Cassiopeia, 528 ; observationsof Encke’s
comet, 529; on Ptolemy’s catalogue
of stars, 530; observations on the solar
eclipse of Sept. 18,1838, 536, 540; on
errors of heliocentric longitude and
ecliptic polar distance of Venus, 228 ;
on the position of Lacaille’s stations
at the Cape of Good Hope, 522.

Atmosphere, on the colours of the, 419.

Azote, on the absorption of, by plants,
237.

Babbage (C.), Prof. Moll’s reply to his
pamphlet on the decline of science in
England, 296.

Babylonia and Chaldza, on the alluvia
of, 426.

Baily (F.) on Ptolemy’s catalogue of
stars, 530,

Barometer, description ofa compensating,
adapted to meteorological purposes,
367.

Baroscope, description of a hydropneu-
matic, 961,

Barry (Dr. M.), researches in embry-
ology, 493.

2N

546

Baryta, alloxanate of, 233.

Barytes, method of distinguishing from
strontian and lime, 78.

Basalt, methed of distinguishing from
trap, 237.

Basilosaurus, on the discovery of the,
302.

Eecquerel (M.) on the phosphorescent
power of electrical light, 394.

Beke (C. T.) on the alluvia of Baby-
lonia and Chaldza, 426.

Berengelite, on the composition of, 89.

Berzelius (M.) on a new metal, 390.

Bessel (Prof.), letter from, to Sir J.
Herschel, 68, 226.

Bevan (B.), notice of the late, 380.

Bichloride of platinum, action of acetone
on, 84.

Bird (Dr. G.) on some of the products
obtained by the reaction of nitric acid
on alcohol, 324.

Birt (W. R.), observations on the shoot-
ing stars of Nov. 12, 1838, 39.

Blood, on the motion of the, 496.

Bonnycastle ( Prof.C.), experimentsmade
to determine the depth of the sea by
the echo, 538.

Botany :—on the respiration of plants,
73; on the distribution of plants in
Colombia, 102 ; on the composition of
wax from Ceroxylon andicola, 155; on
the absorption of azote by plants during
vegetation, 237; on the influence of na-
tive magnesia on the germination and
fructification of vegetables, 238; on
the formation of alkaline and earthy
bodies in plants, 305; on the anatomi-
cal and physiological nature of ergot
in certain grasses, 461; on the anatomy
of the roots of Ophrydez, 462.

Bottger (M.) on the separation of phos-
phorus from its oxide, 544.

Boussingault (M.) on the absorption of
azote by plants during vegetation, 237.

Bowditch (Dr. N.), notice of the late,
63.

Braconnot (M.) on a method of distin-
guishing trap from basalt, 257.

Brewster (Sir D.) on the colours of
mixed plates, 191.

Buchner (M.) on the properties of aco-
nitic acid, 76; on the separation of
copper from arsenic, 78.

Cahours (M. A.) on the composition of
the oil of potatoes, 156.

Carbon, preparation of the dichloride of,
473.

Carson (J.) on the motion of the blood,
496.

Cassiopeia (a), on the suspected variability
of, 528.

Centauri (a), on the parallax of, 316.

INDEX.

Ceroxylon andicola, on the compositiots
of the wax from, 155.

Chabasie, on the formule representing,
46.

Chaldza and Babylonia, on the alluvia
of, 426.

Chalk and strata below the chalk, on the
drift from the, in the counties of Nor-
folk, Suffolk, Essex, &c., 50.

Charters (Capt.) on the geology of South
Africa, 510,

Chirotherium, account of the footsteps
of, 148, 150.

Cinchonia, on the non-existence of the
carbonates of, 392.

Cissampelin, discovery 01, 397.

Coal mines, chemical examination of the
fire damp from, 1.

Coathupe (C. T.), experiments on the
products of respiration at different pe-
riods of the day, 401.

Colin (M.) on the respiration of plants,
78.

Colombia, geographical features of, 10,
95, 179; on the productions of, 99.

Colours, on the effects of the juxtaposi-
tion of, 331; on the theory of acci-
dental, 337, 439.

of mixed plates, observations on
the, 191.

Comet of 1472, curious account of the,
260; Encke’s observations of, 529.
Constable (J. C.) on the use of ammonia

in fixing photographs, 474.

Cooper (J. T.) on hydrocyanic acid, 186;
on a hydropneumatic baroscope, 361 ;
on the visibility of certain rays beyond
the red rays of the solar spectrum, 502.

Copal, fossil, on the composition of, 87.

Copper, on the separation of from arse-
nic, 78.

Crossley (S.) on a pneumatic telegraph,
236, 317.

Crystallization, on a new theory of, 216.

Crystals, on analytic, 19.

Cunningham (J.) on the footsteps of the
Cheirotherium, 148; on impressions
and casts of rain in the quarries of
Storeton Hill, Cheshire, 507.

Curves, on rolling, 152.

Cuvier (Fr.), notice of the late, 66.

Cygni (61), determination of the parallax
of, 68.

Darwin (C.) on the parallel roads of
Glen Roy, 361; on the formation of
mountain chains and volcanoes, 502.

Daubeny (Prof.) on the composition of
asaltfroma mineral spring, New South
Wales, 301.

Davy (Dr. J.) on the male organs of some
of the cartilaginous fishes, 363.

Delvauxene, analysis of, 474.

—

INDEX.

Desmarest (M.), notice of the late, $84.

Drawing, photogenic, on the art of, 196.

Drury (Rey. T.), notice of electrical ex-
citation of a leather strap, 126.

Dulong (P. L.), notice of the late, 65.

Dumas(M.) on the composition of naph-
thalin, 152.

Dumfries, account of the hurricane ex-
perienced in the neighhourhood of, #
Jan. 7th, 1839, 360.

Dumont (M.) on the composition of a
new phosphate of iron, 474.

Earth, oa the state of the interior of the,
52,215.

Earth worms, curious habit of, 159.

Earthquakes, on a probable cause of cer-
tain, 370.

Eclipse, solar, of Sept. 18, 1838, obser-
vations on, 536, 540.

Ecliptic, on the obliquity of the, 314.

Edinburgh Society of Arts, proceedings
of, 463.

Egerton (Sir P. G.) on two impressions
of the hind foot of a gigantic Cheiro-
therium in the new red sandstone of
Cheshire, 150.

Ehrenberg (Carl) on the seleniuret, of
mercury, 392.

Ebrenberg (Prof. G.), award of Wollas-
ton medal to, 374; discoveries respect-
ing fossil infusoria, $77.

Electric force of the Gymnotus, on the
character and direction of the, 211.
Electrical excitation, notice of, in a lea-

ther strap, 126.
light, phosphorescent power of,

394.
Electricity, experimental researches in,

Electrodes, on the polarized condition of,
446.

Embryology, researches in, 493.

Emulsin, decomposition of amygdalin
by, 414.

Encke’s comet, observations of, 529,

Epps (Mr.) on the method of determi-
ning the longitude by moon-culmina-
ting stars, 521.

Ergot, anatomical and physiological na-
ture of, 461.

Ethyle, on the separation of, 542.

Euclid, on a certain demonstration of,
126.

Faraday (Prof.),experimental researches
in electricity, eleventh series, 34;
award of Copley medal to, 132; on
the general magnetic relations and
characters of the metals, 161; on the
character and direction of the electric
force of the Gymnotus, 211; chemical
account of the Cold Bokkeveld mete-
orice stone, 368.

347

Fire damp from coal mines, chemical ex-
amination of, 1.

Fishes, on the male organs of some of the
cartilaginous, 363.

Fluids, on the equilibrium of, 37.

Forbes (Prof.), award of Rumford medal
to, 136; on the colour of steam under
certain circumstances. 121 ; Mr. Web-
ster’s reply to, 184; on the colours of
the atmosphere, 419.

Fossil remains of Palzotherium, Ano-
plotherium, Chzropotamus, 48; of
Glyptodon, 516.

Fox (R. W.) on the formation of metal-
lic veins by voltaic agency, 145.

Fritzsche (M.) on two crystallized sili-
cates of soda, 72.

Fyfe (A.) on recent improvements in
photographic drawing, 463.

Garden (P.) on thehurricane of Jan. 7th,
1839, 360.

Gases, on the combination of, by plati-
num, 127.

Gauss (Prof.), award of the Copley me-
dal to, 57, 131.

Gautier (M.), observations of Encke’s
comet, 529.

Geological Society, proceedings of, 48,
141, 220, 302, 370; address, 419,
502.

Geology :—geological features of Co-
lombia, 10, 95, 179 ; on the formation
of metallic veins by voltaic agency,
145; on the state of the interior of the
earth, 52, 2153; on a method of distin-
guishing trap from basalt, 237; on
the drift from the chalk of Norfolk,
Suffolk, &c., 50; on impressions and
casts of rain in the quarries of Storeton
Hill, Cheshire, 507 ; on an earthquake
in the Island of St. Mary, 220; on the
classification of the older stratified
rocks of Devonshire and Cornwall,
241, 317, 354; on a mineral spring,
Menero Downs, 300; on the geology
of the neighbourhood of Lisbon, 307 ;
on the parallel roads of Glen Roy,
361; on the formation of mountain
chains and volcanoes; on a probable
cause of certain earthquakes, 370; on
the alluvia of Babylonia and Chaldza,
426; on the geology of a part of Asia
Minor, 455, 510; on the geology of
South Africa, 510; physical researches
in, 464.

[For fossil remains see Paleontology. |

Glen Roy, on the parallel roads of, 361.

Glyptodon, on a tooth of the, 516,

Graham ( Prof. J.), award of royal medal
for Chemistry to, 153.

Graptolites, on the occurrence of, in the
slate of Galloway, 307,

2N2

548 INDEX.

Gray (J. E.) on a curious habit of earth
worms, 159.

Grooby (Rev. J.) on the passage of the
moon across the Pleiades in 1839, 177.

Grote and Otto (M. M.) on valerianic
ether, 74.

Grove (W. R.) on voltaic series and com-
bination of gases by platinum, 127;
on a new voltaic combination, 388.

Guaquilite, composition of, 93.

Gymnotus, on the character and direc-
tion of the electric force of the, 211.

Hagen (R.), analysis of crystallized oli-
goclas, 398.

Haggard (W. D.) on the capability of
Peha silver for holding water, 218.

Halliwell (J. O.) on a curious account
of the comet of 1472, 260.

Hamilton (W. J.) on the geology of a
part of Asia Minor, 455, 510.

Harlan (Dr.) on the discovery of the
Basilosaurusand Batrachiosaurus, 302.

Heat, remarkable development of, ob-
served in masses of brine, 27 ; on the
evolution of, by thermo-electricity, 82.

, animal, on a remarkable property
of arteries considered as a cause of,
174.

Heights, on the method of measuring by
boiling water, 179.

Henderson ( Prof.) on the annular eclipse
of the sun, May 15, 1836, 229; on the
parallax of @ Centauri, 316. '

Henwood (W. J.) on the expansive ac-
tion of steam in some of the pumping
engines on the Cornish mines, 481.

Herschel (Sir J. F. W.), chemical ex-
amination of a specimen of native iron
from the Great Fish river in South
Africa, 32; letter to, from Prof. Bessel,
68, 226; on the art of photography,
$65; on the suspected variability of «
Cassiopeia, 528.

Hess (H.) on the composition of wax,
154; on the composition of idocrase,
476.

Holditch (Mr. ) on rolling curves, 152.

Hopkins (T.) on the nature of malaria,
104,

Hopkins ( W.) on the state of the interior
of the earth, 52, 215; on the phzno-
mena of precession and nutation, 364.

Howlett (S. B.) on acompensating baro-
meter for meteorological purposes, 367.

Hume (Sir A.), notice of the late, 379.

Hydrocyanic acid, 186.

Idocrase, on the composition of, 476.

Inductometer, differential, description of,
36.

Integration, note on definite double, 298.

lodide of sodium, action of acids on,
398,

Iron, composition of a new phosphate of,
474,
, meteoric, from Potosi, 394.
» Native, chemical examination of a
specimen of, 32.

Tron ships, correction for the deviation of
the compass on, 497.

Ivanor (M.) on the composition of ido-

* crase,'476.

Tvory (J.) on the equilibrium of fluids,
inreply to Prof. Sylvester, 37; on the
theory of astronomical refraction, 276,
342,

J. B. on the polarized condition of pla-
tina electrodes, and on the theory of se-
condary piles, 446.

J. S. W. on certain conditions under
which light is received from the hea-
venly bodies, 21.

Jellicoe (C.) on the laws of mortality,
215.

Johnston (Prof, J. F. W.) on the formu-
le representing chabasie, 46; on the
composition of some mineral substances
of organic origin, 87; on the constitu-
tion of the resins, 340, 492; on a new
equi-atomic compound of bicyanide
with binoxide of mercury, 492.

Juben (H. M.) on meteoric iron from
Potosi, 394.

Kampen (M. Van), notice of the late,
293.

Kane (Prof. R.) on the theory of the
ethers, 163.

Knight (J. A.), notice of the late, 59.

Kuhlmann (M.) on the action of spongy
platina, 157.

Lacaille’s stations at the Cape of Good
Hope, on the position of, 522,

Langlois (M.) on the non-existence of
the carbonates of quina and cinchonia,
392.

Lassell (Mr.) on a small sextant, 230.

Latanium, account of, 290.

Lepidolite, rose mica, composition of,
395.

Lhotsky (Dr. F.) on a mineral spring,
Menero Downs, 300.

Liebig (M. T.) on the action of acids on
the iodide of sodium, 398.

Light, on certain conditions under which
it is received from the heavenly bodies,
21; researches in the undulatory theory
of, 169, $21; observations onthe theory
of the dispersion of, 261; application of
the chemical rays of, to pictorial repre-
sentation, 865 ; of incandescent coke,
application of the, to photography, 475.

and air, effects of, in restoring faded
colours, 416.

—, electrical, phosphorescent power
of, 394.

INDEX.

Lima, measurements of altitudes in the
vicinity of, 268.

Lime, method of distinguishing from
barytes and strontian, 78.

Lindley (Prof. J.) on the anatomy of the
roots of Ophrydez, 462.

Lipnzan Society, proceedings of, 369,
461.

Lisbon, geology of the neighbourhood of,
307.

Lithia and potash contained in mica, 395.

Lochaber, on the parallel roads of, 361.

Locke (Dr. J.) on the magnetic intensity
and dip for certain positions in Ohio,
535.

Léwig (C.) on the separation of ethyle,
542.

Longitude, method of determining, by
moon-culminating stars, 521.

Lyell (C.) on the occurrence of grapto-
lites in the slate of Galloway, Scotland,
307; on the occurrence of numerous
swallow-holes near Farnham, 509.

Maclean (J.), meteorological observa-
tions made by, during voyages in the
Atlantic and South Pacific Oceans,
268.

Maelear (T.) on a fall of meteorites in
South Africa, 231 ; on the position of
Lacaille’s stations at the Cape of Good
Hope, 522.

Magnetic intensity and dip, determina-
tion of, for certain positions in Ohio,
55oe

—— lines of no dip and of least inten-
sity, comparison of, 81.

relations and characters of the me-
tals, 161.

Magnetism, terrestrial, report on, 136 ;
observations on, 478.

Magnesia, native, influence of, on vegeta-
tion, 238.

Main (Rey. R.) on errors of heliocentric
longitude and ecliptic polar distance of
the planet Venus, 228.

Malaria, observations on the nature of,
104.

Mallett (R.) on the application of the
light of incandescent coke to photo-
graphy, 475.

Marchand (M.) on the action of the sul-
phate of ammonia on glass, 75.

Marum (Prof. D. van), notice of the late,
66.

Masson (M.) on the action of chloride of
zine on alcohol, 156.

Mercury, on a new equi-atomic com-
pound of bicyanide with binoxide of,
492; scleniuret of, 392.

Metal, account of a new, 390.

Metallic veins, formation of, by voltaic
agency, 145,

549

Metals, on the general magnetic relations
and characters of, 161.

Meteoric iron from Potosi, 394,

stone, account of the fall of, at the
Cape of Good Hope, 368, 391.

Meteorites, fall of, in South Africa, 231.

Meteorological observations made during
a residence in Colombia between 1820
and 1830, 10, 95; made during voya-
ges in the Atlantic and South Pacific
oceans, 268.

—a

» monthly, 79,
159, 239, 319, 399, 479.

Meteorological Society, notice respecting,
399;

Middletonite, composition of, 93.

Minerals, on the composition of some or-
ganic, 87.

Mitchell (T.) on the drift from the chalk
of Norfolk, Suffolk, &c., 50.

Moll (Prof. G.), M. Quetelet’s memoir
of, 288.

Montlosier (Count), notice of the late,
381.

Moon, on the passage of the, across the
Pleiades, 177.

Mosander (M.), description of a new
metal, 390.

Murchison (R. I.) on the classification
of the older stratified rocks of Devon-
shire and Cornwall, 241, 217, 354-

Naphthalin, on the composition of, 152.

Necker (L. A.) sur une nouvelle maniére
d énvisager la théorie cristallogra-
phique, 216; on a probable cause of
certain earthquakes, 370.

Nitric acid, on some of the products ob-
tained by the reaction of, on alcohol,
324.

Northampton (Marquis of ) on the Spiro-
linites from the chalk, 461.

Ogilby (W.) on the presumed marsupial
remains from the Stonesfield oolite,
224,

Oligoclas, analysis of crystallized, 398.

Ophrydez, on the anatomy of the roots
of, 462.

Oppermann (M.) on the composition of
wax, 155.

Otto and Grote (MM.) on valerianic
ether, 74.

Owen (Prof. R.) on some fossil remains of
Paleotherium, Anoplotherium, and
Chzropotamus from the fresh-water
beds of the Isle of Wight, 48; some re-
marks on a fossil nearly allied to the
genus Moschus, 49; on the jaws of
Thylacotherium Prevostii from Stones-
field, 141; on the Phascolotherium,
220; onthe teeth of the Zeuglodon,
302; ona tooth and part of a skeleton
of Glytodon, 516.

550 INDEX.

Oxides, metallic, and alloxanic acid, 233;
and oxaluric acid, 235.

Oxus, on the discovery of the source of
the, 52.

P. on the chlorochromic acid of Dr.
Thompson, 230.

Palzontology:—on Cheirotherium, 150;
on the occurrence of Graptolites, 307;
on Thylacotherium Prevostii, 141, 456;
on Basilosaurus, 302, 457; on Phas-
colotherium, 457 ; on the Chzropota-
mus, 459; on the marsupial nature of
the Stonesfield bones, 460; on fossil
Infusoria, 460; on fossil fish in the
Bagshot Sand, 460 ; on Orthoceratites,
461; on Spirolonites, 461; on the state
in which animal matter is found in fos-
sils, 461; on the corals of the lime-
stone of Devon, 461.

Pearson (Rey. Dr.) on the obliquity of
the ecliptic, 314.

Penny (F.) on the application of the
conversion of chlorates and nitrates
into chlorides, and of chlorides into ni-
trates, to the determination of several
equivalent numbers, 218.

Perikline, analysis of crystallized, 397.

Phascolotherium, on the remains of, 220.

Phillips (Prof. J.) on the classification
of the Devonshire strata, 353.

Phillips (R.), letter to, on the constitu-
tion of resins, 340; on the chemical
equivalents of certain bodies, 359; on
the preparation of the chloride of car-
bon, 473.

Phosphorus, separation of, from its oxide,
544.

Photogenic drawing, an account of the
art of, 196; improvements in, 365,
463; application of the light of incan-
descent coke to, 475.

Piles, on the theory of secondary, 446.

Plants, on the respiration of, 73 ; absorp-
tion of azote by, 237 ; influence of na-
tive magnesia on the vegetation of,~
238 ; formation of alkaline and earthy
bodies in, 365; distribution of, in Co-
lombia, 102.

Plateau (Prof. J.) on a general theory
of the visual appearances arising from
the contemplation of coloured objects,
330, 439.

Platina, action of spongy, 157.

electrodes, on the polarized condi-
tion of, 446.

Platinum, on voltaic series and combi-
nation of gases by, 127.

——., bichloride of, action of acetone on,
84.

Pleiades, on the passage of the moon
across the, 177.

Pneumatic telegragh, on a new, 236,517.

Polarization, voltaic, of certain solid and
fluid substances, 43.

elliptical, produced by quartz, 169,
$21.

Potatoes, composition of the oil of, 156.

Powell (Rev. B.) observations on some
points in the theory of the dispersion
of light, 261.

Prater (H.) on the anti-inflammable and
anti-dry-rot powers of the subcarbon-
ate of soda and other salts, 432.

Prinsep (G. A.) on a remarkable heat
observed in masses of brine kept for
some time in large reservoirs, 27.

Quartz, on the elliptical polarization pro-
duced by, 169, 321.

Queckett (E. J.) on the anatomical and
physiological nature of ergot in cer-
tain grasses, 461].

Quetelet (M.), an account of Prof. G.
Moll, 288; on terrestrial magnetism,
478.

Quina, on the non-existence of the car-
bonates of, 392.

Rain, impressions and casts of, in the
quarries of Cheshire, 507.

Regnault (M. V.) on micas containing
lithia and potash, 393 ; on the prepa-
ration of the dichloride of carbon, 473.

Resin, Highgate, on the composition of,

Resins, on the constitution of the, 340,
492.

» mineral, on the origin of, 91.

Respiration, experiments on the products
of, 401.

Retina, on the duration of impressions
on the, 330.

Reviews :—Lubbock’s Treatise on the
Tides, 464; Wallace’s Geometrical
Theorems and Analytical Formule,
467; Faraday’s Experimental Re-
searches in Electricity, 468 ; Scientific
Memoirs, Part V., 472.

Richardson (T.) on the decomposition of
amygdalin by emulsin, 414.

Rigaud (Prof.), notice of the late, 293,

Rigg (R.) on the formation of alkaline
and earthy bodies in plants, 365.

Rocks, classification of the older strati-
fied, of Devonshire and Cornwall,
241, 317, 353, 354—359 ; remarks on
Murchison’s Silurian, and Sedgwick’s
Cambrian, systems of, 450.

Rose (Prof. H.) on the separation of
copper from arsenic, 78; on a method

_of distinguishing strontian from lime,
78; on the preparation of selenic acid,
396.

Sabine (Major), comparison of the mag-
netic lines of no dip and of least in-
tensity, 81.

—

INDEX.

Salep, on the preparation of, 462.
Salmond (W.), notice of the late, 381.
Salts, on the anti-inflammable and anti-

dry-rot powers of some, 432.

Schlotheim (Baron) notice of, 385.

Scheenbein ( Prof.) on the voltaic polari-

gation of certain solid and fluid sub-

stances, 43.

Sea, on the determination of the depth
of by the echo, 538.

Sedgwick (Rev. Prof.) on the classifica-
tion of the older stratified rocks of
Devonshire and Cornwall, 241, 317,
354,

Selenic acid, on the preparation of, 396.

Seleniuret of mercury, occurrence of,
392.

Sharpe (Mr.) on the geology of the
neighbourhood of Lisbon, 307.

Shooting stars on the night of Nov. 12,
1838, observations on, 39.

Silicates of soda, on the composition of
two crystallized compounds of, 72.
Silver, alloxanate of, 233; oxalurate of,

256.

, Pefia, on its capability of holding
water, 218.

Slavinski (M.), astronomical observations
made by, at Wilna, in 1835, 67.

Societies :—

American Philosophical Society, pro-
ceedings of, 535.

Architectural Society, proceedings of,
158.

Astronomical Society, proceedings of,
67, 226, 314, 521.

Cambridge Philosophical Society, pro-
ceedings of, 152, 387, 534.

Edinburgh Society of Arts, proceed-
ings of, 463.

Geological Society, proceedings of,
48, 141, 220, 302, 370, 449, 502;
President’s anniversary address, 449.

Linnzan Society, proceedings of, 369,
461.

Meteorological Society, notice re-
specting, 399.

Royal Society, proceedings of, 52,
133, 211, 359, 412; anniversary ad-
dress of the President, 54; award
of the royal medal for chemistry,
133; of royal medal for mathema-
tics, 131 ; of Copley medal, 131.

Royal Academy of Sciences of Paris,
proceedings of, 388.

Royal Asiatic Society, proceedings of,
543.

Royal Institution, proceedings of, 230,
387.

Royal Irish Academy, proceedings of,
475.

Soda, on two crystallized silicates of, 72.

551

Soda, subcarbonate of, on the anti-inflam-
mable and anti-dry-rot powers of the,
432.

Sodium, action of acids on the iodide of,
398.

Solar eclipse of Sept. 18, 1838, observa-
tions on, 536, 540.

Spring, notice of a mineral, in New
South Wales, 300.

Stars, determination of the parallax of
fixed, 68; on Ptolemy’s catalogue of,
530; shooting, observations on, 29.

Steam, on the colour of, 121, 184, 419;
on the expansive action of, 481.

Sternberg (Count), notice of the late,
384.

Strontian, method of distinguishing from
barytes and lime, 78.

Sulphate of ammonia, on the action of
on glass, 75.

Sussex (H. R. H. the Duke of), address
of, at the anniversary meeting of the
Royal Society, 1838, 53.

Sylvester (Prof.) on the equilibrium of
fluids, 37 ; note on bis paper entitled,
‘fa pendent to Horner’s theorem,” 47 :
on the motion and rest of rigid bodies,
188; on definite double integration,
298.

Talbot (H. F.) on analytic crystals, 19 ;
award of the royal medal for mathe-
matics to, 133; on the art of photo-
genic drawing, 196.

Taylor (J. jun.) on foot-marks in sand-
stone, 508.

Telegraph, on a pneumatic, 236, 317.

Thaulow (C. T.), analysis of crystallized
perikline, 397,

Thermo-electricity, evolution of heat by,
82.

Thompson (R. D.) on the decomposition
of amygdalin by emulsin, 414.

Thylacotherium Prevostii, on the jaws
of, 141; characters of the, 220,

Tides, elementary treatise on the, review
of, 464,

Tovey (J.) on the elliptical polarization
of light produced by quartz, 169, 321.

Trap, method of distinguishing from
basalt, 237.

Trull (Mr.) on the effects of light and air
in restoring faded colours, 416,

Turner (Dr. E.), chemical examination
of the fire damp from the coal mines
near Newcastle, 1.

Varrentrapp (F.) on the composition of
idocrase, 477.

Venus, on the heliocentric longitude and
elliptic polar distance of, 228,

Volcanos, on the formation of, 502,

Voltaic polarization of certain solid and
fluid substances, 43,

552

Watkins (F.) on theevolution of heat by
thermo-electricity, 82.

Wax, composition of, 154.

Webster (T.) on the colour of steam,
184.

Whewell (Prof.), anniversary address of,
374.

Wiggers (M.) on a new vegetable com-
pound, 397.

Williams (Rev. D.) on the classification
of the Devonshire strata, 358.

Winch (N. J.), notice of the late, 380.

Winn (J. M.) on a remarkable property

of arteries considered as a cause of

animal heat, 174.

Wood (Lieut.) on the discovery of the
source of the Oxus, 52.

Wordley (Rev. G.) on an earthquake in
the Island of St. Mary, 220,

Wright (Col. R.), meteorological obser-
vations made in Colombia, between
1820 and 1830, 10, 95, 179.

INDEX.

Yates (J.) on the footsteps of the Cheiro-
therium, 150.

Young (J. R.) on the curvature of sur-
faces, 212.

Zeise (W. C.) on the action of acetone
on the bichloride of platinum, 84.

Zeuglodon, observations on the teeth of
the, 302.

Zinc, chloride of, action of, on alcohol,
156.

Zoology :—on a curious habit of earth
worms, 159 ; on a remarkable property
of arteries, 174; on the character and
direction of the electric force of the
Gymnotus, 211; on the male organs
of some of the cartilaginous fishes,
363; experiments on the products of
respiration at different periods of the
day, 401; researches in embryology,
413.

END OF THE FOURTEENTH VOLUME.

PRINTED BY RICHARD AND JOHN E. TAYLOR,

RED LION COURT, FLEET STREET,

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